US20040159340A1 - Methods for removing and reclaiming unconsolidated material from substrates following fabrication of objects thereon by programmed material consolidation techniques - Google Patents

Abstract

A programmed material consolidation apparatus includes at least one fabrication site and a material consolidation system associated with the at least one fabrication site. The at least one fabrication site may be configured to receive one or more fabrication substrates, such as semiconductor substrates. A machine vision system with a translatable or locationally fixed camera may be associated with the at least one fabrication site and the material consolidation system. A cleaning component may also be associated with the at least one fabrication site. The cleaning component may share one or more elements with the at least one fabrication site, or may be separate therefrom. The programmed material consolidation apparatus may also include a substrate handling system, which places fabrication substrates at appropriate locations of the programmed material consolidation apparatus.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• This application claims the benefit of U.S. Provisional Application No. 60/425,567, filed November 11, 2002, the disclosure of which is hereby incorporated in its entirety by this reference.[0001]
BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0002]
• The present invention relates generally to apparatus for effecting programmed material consolidation techniques, such as stereolithography, and, more particularly, to apparatus that are configured to fabricate features on semiconductor devices and related components. The present invention also relates to programmed material consolidation methods that include use of such apparatus.[0003]
• 2. Background of Related Art[0004]
• Over the past decade or so, a manufacturing technique which has become known as “stereolithography” and which is also known as “layered manufacturing” has evolved to a degree where it is employed in many industries.[0005]
• Basically, stereolithography, as conventionally practiced, involves utilizing a computer, typically under control of three-dimensional (3-D) computer-aided design (CAD) software, to generate a 3-D mathematical simulation or model of an object to be fabricated. The computer mathematically separates or “slices” the simulation or model into a large number of relatively thin, parallel, usually vertically superimposed layers. Each layer has defined boundaries and other features that correspond to a substantially planar section of the simulation or model and, thus, of the actual object to be fabricated. A complete assembly or stack of all of the layers defines the entire simulation or model. A simulation or model which has been manipulated in this manner is typically stored and, thus, embodied as a CAD computer file. The simulation or model is then employed to fabricate an actual, physical object by building the object, layer by superimposed layer. Surface resolution of the fabricated object is, in part, dependent upon the thickness of the layers.[0006]
• A wide variety of approaches to stereolithography by different companies has resulted in techniques for fabricating objects from various types of materials. Regardless of the material employed to fabricate an object, stereolithographic techniques usually involve disposition of a layer of unconsolidated or unfixed material corresponding to each layer of the simulation or model. Next, the material of a layer is selectively consolidated or fixed to at least a partially consolidated, partially fixed, or semisolid state in those areas of a given layer that correspond to solid areas of the corresponding section of the simulation or model. Also, while the material of a layer is being consolidated or fixed, that layer may be bonded to a lower layer of the object which is being fabricated.[0007]
• The unconsolidated material employed to build an object may be supplied in particulate or liquid form. The material may itself be consolidated or fixed. Alternatively, when the unconsolidated material comprises particles, a separate binder material mixed therein or coating the particles may facilitate bonding of the particles to one another, as well as to the particles of a previously formed layer.[0008]
• Surface resolution of the features of a fabricated object depends, at least in part, upon the material being used. For example, when particulate materials are employed, resolution of object surfaces is highly dependent upon particle size, whereas when a liquid is employed, surface resolution is highly dependent upon the minimum surface area of the liquid which can be consolidated or fixed and the minimum thickness of a material layer that can be generated. Of course, in either case, resolution and accuracy of the features of an object being produced from the simulation or model are also dependent upon the ability of the apparatus used to consolidate or fix the material to precisely track the mathematical instructions indicating solid areas and boundaries for each layer of material.[0009]
• Toward that end, and depending upon the type and form of material to be fixed, stereolithographic fabrication processes have employed various fixation approaches. For example, particles have been selectively consolidated by particle bombardment (e.g., with electron beams), disposition of a binder or other fixative in a manner similar to ink-jet printing techniques, and focused irradiation using heat or specific wavelength ranges. In some instances, thin, preformed sheets of material may be superimposed to build an object, each sheet being fixed to a next-lower sheet and unwanted portions of each sheet removed, a stack of such sheets defining the completed object.[0010]
• Early on in its development, stereolithography was used to rapidly fabricate prototypes of objects from CAD files. Prototypes of objects might be built to verify the accuracy of the CAD file defining the object (e.g., an object or negative of a mold to be machined) and to detect any design deficiencies and possible fabrication problems before a design was committed to large-scale production. Stereolithographic techniques have also been used in the fabrication of molds. Using stereolithographic techniques, either male or female forms on which mold material might be disposed could be rapidly generated.[0011]
• In more recent years, stereolithography has been employed to develop and refine object designs in relatively inexpensive materials. Stereolithography has also been used to fabricate small quantities of objects for which the cost of conventional fabrication techniques is prohibitive, such as in the case of plastic objects that have conventionally been formed by injection molding techniques. It is also known to employ stereolithography in the custom fabrication of products generally built in small quantities or where a product design is rendered only once. Finally, it has been appreciated in some industries that stereolithography provides a capability to fabricate products, such as those including closed interior chambers or convoluted passageways, which cannot be fabricated satisfactorily using conventional manufacturing techniques. It has also been recognized in some industries that a stereolithographic object or component may be formed or built around another, pre-existing object or component to create a larger product.[0012]
• Conventionally, stereolithographic apparatus have been used to fabricate freestanding structures. Such structures have been formed directly on a platen or other support system of the stereolithographic fabrication apparatus, which is located within the fabrication tank of the stereolithographic apparatus. As the freestanding structures are fabricated directly on the support system, there is typically no need to precisely and accurately position features of the stereolithographically fabricated structure. As such, conventional stereolithographic apparatus lack machine vision systems for ensuring that structures are fabricated at certain locations.[0013]
• Moreover, conventional stereolithographic apparatus lack support systems, handling systems, and cleaning equipment which are suitable for use with relatively delicate structures, such as semiconductor substrates and semiconductor devices that have been fabricated thereon.[0014]
• Accordingly, there is a need for stereolithography apparatus which are configured to form structures on fabrication substrates, such as semiconductor substrates and semiconductor device components and which include systems for accurately positioning the fabricated structures, supporting and handling the fabrication substrates, and cleaning excess and residual material from the fabrication substrates.[0015]
SUMMARY OF THE INVENTION
• The present invention includes stereolithography apparatus and other programmable material consolidation apparatus and systems that are configured to fabricate features on semiconductor devices or on components that are configured for use with semiconductor devices. In addition, the present invention includes stereolithographic and other programmed material consolidation methods (e.g., stereolithography, layered object manufacturing (LOM), selective laser sintering (SLS), photopolymer jetting, selective particle atomization and consolidation (laser engineered net shaping, or “LENS”), and other so-called “rapid prototyping” technologies) that include use of apparatus according to the present invention. As used herein, the term “stereolithography” and variations thereof, where applicable, are intended to denote all types of programmed material consolidation techniques and is used synonymously with the phrase “programmed material consolidation” and variations thereof.[0016]
• A programmed material consolidation apparatus, or “stereolithography apparatus” for simplicity, according to the present invention includes a fabrication tank, which is also referred to herein as a “fabrication chamber” or even more broadly as a “fabrication site.” The fabrication tank includes a platen or other support system suitable for carrying substrates upon which structures are to be stereolithographically fabricated, which may also be termed “fabrication substrates.” By way of example only, the fabrication tank and the support therein may be sized and configured to receive one or more semiconductor substrates, each of which carries a plurality of semiconductor devices. Alternatively, or in addition, the platen or other support system may be configured to support freestanding structures as they are fabricated. In addition, the fabrication tank may include a reservoir that is configured to hold a volume of unconsolidated material, such as a liquid polymer.[0017]
• A material consolidation system is associated with the fabrication tank in such a way as to direct consolidating energy (e.g., in the form of radiation, such as a laser beam or less-focused radiation) to a surface of the quantity of unconsolidated material within the reservoir of the fabrication tank. When selective consolidation is desired, a high level of precision may be achieved when the consolidating energy is focused and the surface of the quantity of unconsolidated material and the focal point for the consolidating energy substantially intersect one another.[0018]
• Optionally, a stereolithography apparatus that incorporates teachings of the present invention may include a machine vision system. The machine vision system includes an optical detection element, such as a camera, as well as a controller or processing element, such as a computer processor or a collection of computer processors, associated with the optical detection element. The optical detection element may be positioned in a fixed location relative to the fabrication tank or configured to move relative to the fabrication tank.[0019]
• When included as part of a stereolithographic apparatus that incorporates teachings of the present invention, the optical detection element of a machine vision system is useful for identifying the locations of recognizable features, including, without limitation, features on a fabrication substrate and features, such as fiducial marks, at a fabrication site. For example, the optical detection element may be configured and/or located to “see” relatively large structures, such as those that can be seen by the naked eye (i.e., macroscopic structures), such as the locations of semiconductor devices upon a fabrication substrate. Alternatively, or in addition, the optical detection element may be configured and/or located to “see” very small, even microscopic structures.[0020]
• Another optional feature of a stereolithographic apparatus of the present invention is a cleaning component. A cleaning component may be positioned and configured to remove excess liquid polymer from a fabrication substrate while the fabrication substrate remains positioned upon a support system that is associated with the fabrication tank. Such a cleaning component may comprise at least a part of the fabrication tank and, thus, operate prior to introduction of another fabrication substrate into the fabrication tank. Alternatively, excess liquid polymer may be removed from a fabrication substrate during or following removal thereof from the fabrication tank.[0021]
• Additionally, a stereolithographic apparatus that incorporates teachings of the present invention may include a material reclamation system. The material reclamation system may be associated with one or both of the fabrication tank and a cleaning component, if the stereolithographic apparatus includes a cleaning component. By way of example, the material reclamation system may collect material from the cleaning component and recycle the same into the fabrication tank.[0022]
• A programmed material consolidation system that incorporates teachings of the present invention may include a plurality of fabrication sites and share a common material consolidation system, machine vision system, handling system, cleaning component, or material reclamation system.[0023]
• The present invention also includes methods for calibrating stereolithographic apparatus that incorporate teachings of the present invention. For example, the locations at which unconsolidated material may be selectively consolidated may be calibrated with a machine vision system. As another example, the magnification of a machine vision system may be calibrated. Also, a material consolidation system of a stereolithographic apparatus according to the present invention may be calibrated to optimize the linearity with which selectively consolidating energy impinges on a surface of unconsolidated material.[0024]
• Programmed material consolidation fabrication processes, including methods of using each of the features described herein, are also within the scope of the present invention. In particular, stereolithographic fabrication processes that incorporate teachings of the present invention include the use of stereolithographic techniques to fabricate features on another structure, or fabrication substrate, such as a semiconductor substrate or semiconductor device component (e.g., a lead frame, a circuit board, etc.).[0025]
• Other features and advantages of the present invention will become apparent to those of skill in the art through consideration of the ensuing description, the accompanying drawings, and the appended claims.[0026]
BRIEF DESCRIPTION OF THE DRAWINGS
• In the drawings, which depict exemplary embodiments of various features of the present invention:[0027]
• FIG. 1 is a schematic representation of various possible elements of a stereolithographic apparatus for fabricating features on semiconductor devices or associated components in accordance with the present invention, the elements including a fabrication tank, a material consolidation system, a machine vision system, a cleaning component, and a material reclamation system;[0028]
• FIG. 2 schematically depicts an exemplary stereolithographic apparatus in which a single material consolidation system and/or a single machine vision system may be shared by a plurality of fabrication tanks;[0029]
• FIG. 3 schematically depicts an exemplary embodiment of fabrication tank that may be used in a stereolithographic apparatus of the present invention, the fabrication tank including a cavity and a reservoir which are continuous with one another;[0030]
• FIG. 3A illustrates an exemplary support element of the fabrication tank of FIG. 3, which support element has a substantially planar support surface;[0031]
• FIG. 3B shows another exemplary support element of the fabrication tank shown in FIG. 3, which support element includes recesses formed in the support surface thereof;[0032]
• FIG. 3C illustrates an exemplary volume control element of the fabrication tank depicted in FIG. 3, which volume control element is configured to add unconsolidated material to and/or remove unconsolidated material from the reservoir of the fabrication tank;[0033]
• FIG. 3D depicts another exemplary volume control element of the fabrication tank of FIG. 3, which volume control element is configured to displace unconsolidated material located within the reservoir of the fabrication tank;[0034]
• FIG. 3E schematically depicts a stereolithographic fabrication tank which includes another variation of volume control and surface level control element;[0035]
• FIG. 4 schematically depicts another embodiment of fabrication tank that includes a rotatable support element and which may be used in a stereolithographic apparatus according to the present invention, such as those shown in FIGS. 1 and 2, which fabrication tank also comprises a cleaning component and a material reclamation system;[0036]
• FIG. 4A is a top view of an example of a retention system for use with a support system of the fabrication tank of FIG. 4;[0037]
• FIG. 4B is a cross-section taken along[0038]line4B-4B of FIG. 4A;
• FIG. 4C is a top view of another example of a retention system for use with a support system of the fabrication tank of FIG. 4;[0039]
• FIG. 4D is a cross-section taken along[0040]line4D D of FIG. 4C;
• FIG. 4E is a cross-sectional representation of another embodiment of support system that may be used in a fabrication tank of a semiconductor fabrication apparatus according to the present invention;[0041]
• FIG. 4F is a top view of the support system shown in FIG. 4E;[0042]
• FIG. 5 is a schematic representation of still another exemplary embodiment of fabrication tank that incorporates teachings of the present invention;[0043]
• FIG. 6 is a schematic representation of an exemplary embodiment of a material consolidation system according to the present invention, which is configured to focus consolidating energy so as to selectively consolidate unconsolidated material which has been placed over a fabrication substrate;[0044]
• FIG. 7 schematically depicts another exemplary embodiment of material consolidation system, which is configured to generally consolidate unconsolidated material which has been placed over a fabrication substrate;[0045]
• FIG. 8 schematically illustrates an exemplary embodiment of machine vision system that may be used with a fabrication tank of a stereolithographic apparatus according to the present invention, with the machine vision system being configured to move relative to a surface of unconsolidated material which is to be consolidated by the stereolithographic apparatus;[0046]
• FIG. 9 is a schematic representation of another exemplary embodiment of machine vision system, which embodiment is configured to remain at a fixed location relative to a surface of unconsolidated material which is to be consolidated by a stereolithographic apparatus with which the machine vision system is used;[0047]
• FIG. 10 is a schematic representation of another embodiment of cleaning component, as well as an exemplary embodiment of a material reclamation system;[0048]
• FIG. 11 is a schematic representation of yet another embodiment of cleaning component that may be used as part of a stereolithographic apparatus according to the present invention;[0049]
• FIG. 12 is a schematic representation of the manner in which the locations at which a layer of unconsolidated material is selectively consolidated may be calibrated with a machine vision system of a stereolithographic apparatus of the present invention;[0050]
• FIG. 13 is a top view of a fabrication tank, depicting an exemplary manner in which a linearity calibration may be conducted; and[0051]
• FIG. 14 is a cross-sectional representation of a fabrication substrate and an object being stereolithographically fabricated thereon in accordance with teachings of the present invention.[0052]
DETAILED DESCRIPTION
• An exemplary[0053]stereolithographic apparatus10 for fabricating features on semiconductor substrates52,semiconductor devices54 or associated components (e.g., lead frames, circuit boards, etc.) (not shown) orother fabrication substrates50 is schematically depicted in FIG. 1. As shown,stereolithographic apparatus10 includes afabrication tank100 and amaterial consolidation system200, amachine vision system300, acleaning component400, and amaterial reclamation system500 that are associated withfabrication tank100. The depictedstereolithographic apparatus10 also includes asubstrate handling system600, such as a rotary feed system or linear feed system available from Genmark Automation Inc. of Sunnyvale, Calif., for movingfabrication substrates50 from one system of stereolithographic apparatus to another. Features of one or more of the foregoing systems may be associated with one ormore controllers700, or processing elements, such as computer processors or smaller groups of logic circuits, in such a way as to effect their operation in a desired manner.
• [0054]Controller700 may comprise a computer or a computer processor, such as a so-called “microprocessor,” which may be programmed to effect a number of different functions. Alternatively,controller700 may be programmed to effect a specific set of related functions or even a single function. Eachcontroller700 ofstereolithographic apparatus10 may be associated with a single system thereof or a plurality of systems so as to orchestrate the operation of such systems relative to one another.
• [0055]Fabrication tank100 includes achamber110 which is configured to contain asupport system130. In turn,support system130 is configured to carry one ormore fabrication substrates50. By way of example only, the types offabrication substrates50 thatsupport system130 may be configured to carry may include, without limitation, a bulk semiconductor substrate52 (e.g., a full or partial wafer of semiconductive material, such as silicon, gallium arsenide, indium phosphide, a silicon-on-insulator (SOI) type substrate, such as silicon-on-ceramic (SOC), silicon-on-glass (SOG), or silicon-on-sapphire (SOS), etc.) that includes a plurality ofsemiconductor devices54 thereon.
• [0056]Fabrication tank100 may also have areservoir120 associated therewith.Reservoir120 may be continuous withchamber110. Alternatively,reservoir120 may be separate from, but communicate with,chamber110 in such a way as to provideunconsolidated material126 thereto.Reservoir120 is configured to at least partially contain avolume124 ofunconsolidated material126, such as a photoimageable polymer, or “photopolymer,” particles of thermoplastic polymer, resin-coated particles, or the like.
• Photopolymers believed to be suitable for use with a[0057]stereolithography apparatus10 according to the present invention include, without limitation, ACCURA® SI 40 Hc and AR materials, ACCURA® SI 40 ND material, and CIBATOOL SL 5170, SL 5210, SL 5530, and SL 7510 resins. The ACCURA® materials are available from 3D Systems, Inc., of Valencia, Calif., while the CIBATOOL resins are available from Ciba Specialty Chemicals Company of Basel, Switzerland.
• [0058]Reservoir120 or another component associated with one or both offabrication tank100 andreservoir120 thereof may be configured to maintain asurface128 of a portion ofvolume124 located withinchamber110 at a substantially constant elevation relative tochamber110.
• A[0059]material consolidation system200 is associated withfabrication tank100 in such a way as to direct consolidatingenergy220 intochamber110 thereof, toward at least areas ofsurface128 ofvolume124 ofunconsolidated material126 withinreservoir120 that are located overfabrication substrate50. Consolidatingenergy200 may comprise, for example, electromagnetic radiation of a selected wavelength or a range of wavelengths, an electron beam, or other suitable energy for consolidatingunconsolidated material126.Material consolidation system200 includes asource210 of consolidatingenergy220. If consolidatingenergy220 is focused,source210 or alocation control element212 associated therewith (e.g., a set of galvanometers, including one for x-axis movement and another for y-axis movement) may be configured to direct, or position, consolidatingenergy220 toward a plurality of desired areas ofsurface128. Alternatively, if consolidatingenergy220 remains relatively unfocused, it may be directed generally towardsurface128 from a single, fixed location or from a plurality of different locations. In any event, operation ofsource210, as well as movement thereof, if any, may be effected under the direction ofcontroller700.
• When[0060]material consolidation system200 directs focused consolidatingenergy220 towardsurface128 ofvolume124 ofunconsolidated material126,stereolithographic apparatus10 may also include amachine vision system300.Machine vision system300 facilitates the direction of focused consolidatingenergy220 toward desired locations of features onfabrication substrate50. As withmaterial consolidation system200, operation ofmachine vision system300 may be proscribed bycontroller700. If any portion ofmachine vision system300, such as acamera310 thereof, moves relative tochamber110 offabrication tank100, that portion ofmachine vision system300 may be positioned so as provide a clear path to all of the locations ofsurface128 that are located over eachfabrication substrate50 withinchamber110.
• Optionally, as schematically depicted in FIG. 2, one or both of material consolidation system[0061]200 (which may include a plurality of mirrors214) andmachine vision system300 of astereolithographic apparatus10 may be oriented and configured to operate in association with a plurality offabrication tanks100. Of course, one ormore controllers700 would be useful for orchestrating the operation ofmaterial consolidation system200,machine vision system300, andsubstrate handling system600 relative to a plurality offabrication tanks100.
• With returned reference to FIG. 1,[0062]cleaning component400 ofstereolithographic apparatus10 may also operate under the direction ofcontroller700.Cleaning component400 ofstereolithographic apparatus10 may be continuous with achamber110 offabrication tank100 or positioned adjacent tofabrication tank100. If cleaningcomponent400 is continuous withchamber110, anyunconsolidated material126 that remains on afabrication substrate50 may be removed therefrom prior to introduction of anotherfabrication substrate50 intochamber110.
• If[0063]cleaning component400 is positioned adjacent tofabrication tank100, residualunconsolidated material126 may be removed from afabrication substrate50 asfabrication substrate50 is removed fromchamber110. Alternatively, anyunconsolidated material126 remaining onfabrication substrate50 may be removed therefrom afterfabrication substrate50 has been removed fromchamber110, in which case the cleaning process may occur as anotherfabrication substrate50 is positioned withinchamber110.
• [0064]Material reclamation system500 collects excessunconsolidated material126 that has been removed from afabrication substrate50 by cleaningcomponent400, then returns the excessunconsolidated material126 toreservoir120 associated withfabrication tank100.
Fabrication Sites
• Turning now to FIGS.[0065]3-5, various exemplary embodiments of fabrication sites, chambers, or tanks, that may be used in a stereolithographic apparatus10 (FIG. 1) or other programmable material consolidation apparatus or system that incorporates teachings of the present invention are illustrated.
• FIG. 3 shows a[0066]fabrication tank100′ which includes achamber110′ that is continuous with areservoir120′. Asupport system130′, which includes a platen, orsupport element132′, apositioning element140′, and anactuation element146′, is located withinreservoir120′, beneathchamber110′, and may be moved to a plurality of different vertical positions, or elevations, therein.
• A substrate-supporting surface of[0067]support element132′, which is also referred to herein as asupport surface134′ for the sake of simplicity, may be substantially planar, as shown in FIG. 3A. Alternatively, as depicted in FIG. 3B,support surface134′ may have one ormore recesses136′ formed therein, eachrecess136′ being configured to receive at least a portion of afabrication substrate50. Additionally, eachrecess136′ may be configured to position afabrication substrate50 in a desired orientation upon introduction of the same thereinto.Support surface134′ may be configured to carry asingle fabrication substrate50 or a plurality offabrication substrates50.
• Positioning[0068]element140′ may be coupled to abottom surface138′ ofsupport element132′ or otherwise operatively associated withsupport element132′.Positioning element140′ is depicted as being an elongate structure that includes acoupling end142′ that has been secured tobottom surface138′, as well as an opposite,actuation end144′. Nonetheless,positioning elements140′ of other configurations are also within the scope of the present invention. By way of example only,positioning element140′ may comprise a hydraulically or pneumatically actuated piston, a screw, a linear actuator or stepper element, a series of gears, or the like.
• [0069]Actuation element146′ is, of course, associated with and configured to effect movement ofpositioning element140′. Accordingly, examples ofactuation elements146′ that may be used as part ofsupport system130′ include, but are not limited to, hydraulic actuators, pneumatic actuators, screw-drive motors, stepper motors, and other known actuation means for controlling the movement ofpositioning element140′ in such a way as to causesupport element132′ to move from one elevation to another in a substantially vertical direction and with a higher degree of dimensional precision. Additionally,positioning element140′ andactuation element146′ may desirably elevatesupport element132′ and, thus, eachfabrication substrate50 thereon out ofchamber110′ to facilitate movement of eachfabrication substrate50 by substrate handling system600 (FIGS. 1 and 2). Alternatively, the level at which surface128 ofvolume124 ofunconsolidated material126 is located may be lowered belowsupport surface134′.
• Control over the operation of[0070]actuation element146′ and, thus, over the movement ofpositioning element140′ and elevation ofsupport element132′ may be provided bycontroller700 or anotherprocessing element105′ (e.g., a processor or smaller collection of logic circuits), which may be dedicated for use withsupport system130′ orfabrication tank100′, in communication therewith, either as a part offabrication tank100′ or, more generally, as a part of stereolithographic apparatus.
• [0071]Reservoir120′ may include a surfacelevel control element150′ which is configured to maintainsurface128 ofvolume124 ofunconsolidated material126 at a substantially constant elevation. Surfacelevel control element150′ may include asurface level sensor152′ and an element for adjustingvolume124 ofunconsolidated material126, which element is referred to herein as a “volume adjustment element”154′. Bothsurface level sensor152′ andvolume adjustment element154′ may communicate withcontroller700 orprocessing element105′, which monitors the level ofsurface128, as indicated by signals produced and transmitted bysurface level sensor152′, and facilitates adjustment or displacement ofvolume124 by way ofvolume adjustment element154′ to compensate for changes in the elevation ofsurface128 and thereby maintainsurface128 at a substantially constant elevation.
• By way of example only,[0072]surface level sensor152′ may comprise a laser sensor and reflected laser beam, which may be used in connection with one or more charge-coupled device (CCD) cameras or complementary metal-oxide-semiconductor (CMOS) cameras. Triangulation techniques may be used with such devices to determine the distance ofsurface128 from a fixed point and, thus, the elevation, or level, at which surface128 is located.
• If[0073]volume adjustment element154′ is configured to changevolume124 ofunconsolidated material126 withinreservoir120′,volume adjustment element154′ may comprise apump156′ or series ofpumps156′ that may removeunconsolidated material126 fromreservoir120′ and transport the same to anexternal reservoir158′, as well as addunconsolidated material126 from anexternal reservoir158′ toreservoir120′, as shown in FIG. 3C.
• If[0074]volume adjustment element154′ is instead configured to displace a portion ofvolume124 located withinreservoir120′,volume adjustment element154′ may, for example, comprise a piston or other displacement member160′ which may be incrementally introduced into and withdrawn fromreservoir120′, as shown in FIG. 3D. Of course, movement of such a displacement member160′ may be effected by anactuator162′ therefor, such as a hydraulic actuator, a pneumatic actuator, a screw-drive motor, a stepper motor, or the like. Alternatively, vibrations may be transmitted directly tounconsolidated material126 by, for example, a piston face, diaphragm, or the like.
• Alternatively, as shown in FIG. 3E, a[0075]volume adjustment element154″ may include one or more apertures orother openings102 in aside wall101 offabrication tank100′ that havelower edges103 that are positioned at an elevation withinfabrication tank100′ at which surface128 ofvolume124 ofunconsolidated material126 is to be maintained. In addition, surfacelevel control element154″ includes one ormore receptacles104 that communicate withopenings102 to receive overflowingunconsolidated material126 assupport element132′ an a substrate or other workpiece thereon, as well as any stereolithographically fabricated objects, are lowered intofabrication tank100′ and displaceunconsolidated material126 therein. A pumping system or othermaterial recycling element105 may communicate with eachreceptacle104 in such a way as to return overflowedunconsolidated material126 totank100′ assupport element132′ is raised to facilitate stereolithographic fabrication of one or more other objects.
• The introduction of[0076]support element132′ or one ormore fabrication substrates50 into avolume124 ofunconsolidated material126 contained withinreservoir120′ may result in the introduction of gas or air bubbles intounconsolidated material126. Accordingly, referring again to FIG. 3,fabrication tank100′ may optionally include abubble elimination system165′ which is associated with a boundary orwall114′ ofreservoir120′ or withsupport system130′ so as to facilitate the removal of air or gas bubbles (not shown) fromunconsolidated material126. By way of example,bubble elimination system165′ may comprise an ultrasonic transducer of a known type (e.g., a piezoelectric transducer), which causesfabrication tank100′ orsupport system130′ thereof to vibrate. Vibrations infabrication tank100′ orsupport system130′ are transmitted tounconsolidated material126 withinreservoir120′, causing any bubbles therein to dislodge from a structure to which they are adhered and float to surface128, where they will pop or may be removed, such as by use of negative pressure.
• Referring now to FIG. 4, another exemplary embodiment of[0077]fabrication tank100″ is illustrated.Fabrication tank100″ includes areservoir120″ at the base thereof and achamber110″ which is located overreservoir120″ and which is continuous therewith. In addition,chamber110″ offabrication tank100″ includes amaterial reclamation zone170″, as well as acleaning zone180″ located abovematerial reclamation zone170″.
• As shown,[0078]reservoir120″ may be configured to contain a substantiallyconstant volume124 of material, includingunconsolidated material126 and, if stereolithographic processes have been initiated,consolidated material126′ (FIG. 14). Accordingly,reservoir120″ may include a surfacelevel control element150′, such as that described above in reference to FIGS. 3, 3C, and3D.
• A[0079]support system130″ offabrication tank100″ includes asupport element132″ which is positionable at a plurality of distinct, precise elevations withinreservoir120″ and, optionally, withinchamber110″. Movement ofsupport element132″ is effected by apositioning element140″.Positioning element140″ is, in turn, associated with anactuation element146″, which may be actuated to causepositioning element140″ to move so as to positionsupport element132″ at a desired elevation withinreservoir120″ orchamber110″. Additionally,positioning element140″ may elevatesupport element132″ and, thus, anyfabrication substrates50 thereon out ofchamber110″ to facilitate handling offabrication substrates50 by substrate handling system600 (FIGS. 1 and 2).Actuation element146″ may communicate withcontroller700 orprocessing element105′ in such a way thatcontroller700 directs the operation ofactuation element146″.
• In addition,[0080]actuation element146″ may be configured to rotatesupport element132″ about an axis A thereof and within a plane P in which supportelement132″ is located. Alternatively,fabrication tank100″ may include arotation element148″ that is independent fromactuation element146″ and which is configured to causesupport element132″ to rotate. Such rotation may occur under instructions, in the form of signals or carrier waves, fromcontroller700 orprocessing element105′. By way of example and not by way of limitation, a stepper motor or a screw-drive motor that has been modified to move a screw, then maintain the screw in a substantially constant location when the screw has reached one or more certain positions (e.g.,material reclamation zone170″ or cleaningzone180″), may be used as eitheractuation element146″ orrotation element148″.
• When[0081]support element132″ is moved intomaterial reclamation zone170″ or cleaningzone180″ ofchamber110″,actuation element146″ orrotation element148″ may causesupport element132″ to accelerate and rotate at a sufficient speed that centrifugal force causes any excessunconsolidated material126 and/or cleaningagents127, such as water, solvents forunconsolidated material126, detergents, combinations thereof, or the like, to be removed from afabrication substrate50 carried thereby while remaining substantially within the same plane as that within whichsupport element132″ is located.
• [0082]Material reclamation zone170″ andcleaning zone180″ may each be provided with areceptacle172″,182″, respectively, that extends substantially around the periphery of an inner boundary orwall114″ ofreservoir120″.Receptacles172″ and182″ are each positioned at approximately the same elevations withinreservoir120″ that supportelement132″ will be located when positioned withinreclamation zone170″ andcleaning zone180″ thereof, respectively. Accordingly, as excessunconsolidated material126 and/or cleaningagents127 are removed, by spinning, from eachfabrication substrate50 that is carried bysupport element132″,receptacle172″,182″ will receive substantially all of the excessunconsolidated material126 or cleaningagents127 that are removed therefrom.
• Since[0083]support element132″ offabrication tank100″ is configured to be rotated, or spun, at relatively high speed,support element132″ may be configured to retain one ormore fabrication substrates50 during such rotation, or spinning. FIGS. 4A and 4B depict an example of aretention system190 that may be used on asupport element132″ to secure afabrication substrate50 in place thereon, particularly whensupport element132″ is being accelerated to spin at high rotational speeds.
• The depicted[0084]retention system190 includes a raisedperiphery191 that forms areceptacle192 within which afabrication substrate50 may be substantially laterally contained. Thus, whensupport element132″ is rotated, or spun, raisedperiphery191 prevents afabrication substrate50 that is being carried bysupport element132″ from being thrown laterally therefrom. One or more alignment features193, which ensure thatfabrication substrate50 has been properly positioned and oriented withinreceptacle192, may also be formed by the inner border of raisedperiphery191. In addition,retention system190 may include one ormore access elements194 which provide access to portions of anouter periphery55 of afabrication substrate50 located withinreceptacle192, thereby facilitating removal offabrication substrate50 fromreceptacle192, as well as placement of anotherfabrication substrate50 therein.
• Optionally, raised[0085]periphery191 may protrude above anupper surface56 of fabrication substrate50 a distance which comprises a maximum distance a stereolithographically fabricated object (not shown) may protrude fromupper surface56.Unconsolidated material126 that is introduced ontoupper surface56 offabrication substrate50 may be laterally contained by raisedperiphery191. Anupper surface22U′ of theuppermost layer22′ ofunconsolidated material126 within the confines of raisedperiphery191 may be planarized by translating aplanarizing element195, such as a meniscus blade (which includes a meniscus at the trailing edge thereof) or air knife, thereacross to removeunconsolidated material126 and/or smoothupper surface22U′. An uppermost surface of raisedperiphery191 defines the level at whichplanarizing element195 may be translated acrossunconsolidated material126.
• Raised[0086]periphery191 may be an integral part of asupport surface134″ ofsupport element132″, with the majority ofretention system190 being formed insupport surface134″. Alternatively,retention system190 may be formed separately from the manufacture ofsupport element132″ and secured to supportsurface134″ thereof. By way of example only, stereolithographic processes may be employed to fabricateretention system190 onsupport surface134″, such as by usingstereolithographic apparatus10.
• Additionally,[0087]retention system190 may include a sealingelement198, which may be positioned onsupport surface134″ so as to underlie at least a periphery of afabrication substrate50 positioned thereover. By way of example only, sealingelement198 may comprise a somewhat flattened ring which is configured to seal against anouter periphery55 offabrication substrate50, as well as regions ofbottom surface51 offabrication substrate50 which are located adjacent toouter periphery55. Such a sealingelement198 may preventunconsolidated material126 from contactingbottom surface51 offabrication substrate50 andsupport surface134″ ofsupport element132″. Exemplary materials from which sealingelement198 may be fabricated include, without limitation, compressible, resilient materials, such as silicone, polyurethane, ethylene vinyl alcohol (EVA), or the like.
• Also, in order to secure[0088]fabrication substrate50 in place relative to supportsurface134″,retention system190 may include one ormore pressure ports196, which are configured to communicate with a pressure source197 (e.g., a vacuum or an air compressor). Assupport element132″ is configured to be rotated, eachpressure port196 may be fitted with avalve199, which seals thatpressure port196 whenpressure source197 is not in communication therewith. Of course,such valves199 are not necessary whensupport element132″ does not rotate, as infabrication tank100′. As a negative pressure is applied through the one ormore pressure ports196 to abottom surface51 offabrication substrate50, the negative pressure pullsfabrication substrate50 against sealingelement198, sealingbottom surface51 against sealingelement198. In addition to securingfabrication substrate50 oversupport surface134″ and possibly providing a cushion forfabrication substrate50, as noted previously, sealingelement198 may prevent unconsolidated material from contactingbottom surface51 andsupport surface134″. Operation ofpressure source197 and, if necessary, communication thereof withpressure ports196 may be under control ofcontroller700,processing element105′, or another processing element that is dedicated for use withretention system190.
• FIGS. 4C and 4D illustrate a variation of[0089]retention system190′, which is useful withsupport element132″ offabrication tank100″.Retention system190′ includes one ormore ejection elements196′.Ejection elements196′ are useful for removingfabrication substrate50 fromreceptacle192, as well as for breaking a seal caused by the presence of a negative pressure beneathfabrication substrate50, which is applied against at least a portion ofbottom surface51 thereof. Operation ofejection elements196′ may be controlled by way of acontroller700 in communication therewith. By way of example only, eachejection element196′ may comprise a mechanical piston that may be recessed withinsupport surface134″ to facilitate placement of afabrication substrate50 thereon or raised by anactuation element197′ (e.g., a pneumatic, hydraulic, or mechanical actuation element) to protrude fromsupport surface134″ and eject afabrication substrate50 fromrecess192 and raisefabrication substrate50 to facilitating grasping thereof bysubstrate handling system600. In this example, it isactuation element197′ that communicates withcontroller700,processing element105′, or another processing element and that operates in accordance with instructive signals, or carrier waves, fromcontroller700,processing element105′, or the other processing element.
• Alternatively, referring again to FIGS. 4A and 4B, each[0090]ejection element196′ may comprise apressure port196, which, as described previously herein, communicates with one or more pressure sources197. A negative air pressure may be applied throughpressure port196 to abottom surface51 of afabrication substrate50 to secure the same to supportsurface134″. Conversely, a positive air pressure may be forced throughport196 againstbottom surface51 to eject afabrication substrate50 fromsupport surface134″. As shown, eachpressure source197 may communicate withcontroller700,processing element105′, or another processing element (FIG. 4), which directs operation ofpressure source197 by known means. The use ofejection element196′ to apply positive air pressure tobottom surface51 offabrication substrate50 may also be used to break a seal, if any, betweenbottom surface51 and a feature, such as a sealingelement198, ofsupport element132″.
• Optionally,[0091]pressure ports196 may be configured and the output ofpressure source197 modulated so as to create a circulating airflow beneathbottom surface51 as positive pressure is forced therethrough, causingfabrication substrate50 to be lifted off ofsupport surface134″ in such a way as to hover thereover in accordance with Bernoulli's Law. Such anejection element196′ is, therefore, useful for facilitating the grasping offabrication substrate50 by a substrate handling system600 (FIGS. 1 and 2) ofstereolithography apparatus10,10′, as well as to remove anyunconsolidated material126 fromsupport surface134″.
• Another embodiment of[0092]support system130′″ that may be used in afabrication tank100,100′,100″ of astereolithographic apparatus10,10′ according to the present invention is shown in FIGS. 4E and 4F.Support system130′″ includes asupport element132′″ and alocking ring191′″ that surrounds at least a portion ofouter periphery55 offabrication substrate50 to secure the same to supportelement132′″. Lockingring191′″ forms areceptacle192′″ within whichfabrication substrate50 is laterally contained. Anupper surface56 offabrication substrate50, however, remains substantially exposed.
• Locking[0093]ring191′″ includes an upper, laterally inwardly extendinglip193′″ which is configured to contact anupper surface56 offabrication substrate50. As lockingring191′″ also defines a fixed distance between asupport surface134′″ andlip193′″, which distance may not be the same as the thickness of afabrication substrate50 to be positioned therebetween, one ormore spacers194′″ may be fabricated (e.g., stereolithographically) or positioned onsupport surface134′″ so thatsupport system130′″ may be tailored to accommodatethinner fabrication substrates50.Spacers194′″ are also useful for preventingbottom surface51 offabrication substrate50 from adhering tosupport surface134′″ ofsupport element132′″.Support elements132′″ of this type, including stereolithographically fabricatedsupport elements132′″, may be reused.
• A thickness of[0094]lip193′″ may define a maximum distance a stereolithographically fabricated object (not shown) may protrude fromupper surface56 offabrication substrate50. The thickness oflip193′″ may be increased by positioning or forming (e.g., stereolithographically) anextension ring202′″ thereon.Unconsolidated material126 that is introduced ontoupper surface56 offabrication substrate50 may be laterally contained bylip193′″. By way of example only,unconsolidated material126 may be introduced within the confines oflip193′″ and any extension rings202′″ thereon by loweringsupport system130′″ beneath surface128 (FIG. 4) ofvolume124 ofunconsolidated material126 so as to permitunconsolidated material126 to flow therein, then raisingsupport system130′″ so that an upper edge oflip193′″ or anextension ring202′″ thereon is substantially coplanar withsurface128.
• An[0095]upper surface22U′ of theuppermost layer22′ ofunconsolidated material126 within the confines oflip193′″ and any extension rings202′″ thereon may be planarized by translating aplanarizing element195, such as a meniscus blade or air knife, thereacross (FIG. 4B). An uppermost surface oflip193′″ or anextension ring202′″ thereon defines the level at whichplanarizing element195 may be translated acrossunconsolidated material126.
• Optionally, with returned reference to FIG. 4,[0096]fabrication tank100″ may include abubble elimination system165′, such as that described in reference to FIG. 3. Alternatively,stereolithographic fabrication tanks100, such as those that havechambers110 with relatively small volumes (e.g., which are sufficient to contain only a single semiconductor substrate52), may include bubble elimination systems that create a negative pressure, or vacuum, within the chambers thereof. Such a bubble elimination system may, for example, include one or more sealing elements, which substantially seal stereolithographic apparatus10 (FIG. 1)chamber110, as well as a negative pressure source that communicates at least withchamber110 so as to facilitate the creation of a negative pressure therein.
• Turning now to FIG. 5, still another embodiment of[0097]fabrication tank100′″ that may be used in astereolithographic apparatus10,10′ (FIGS. 1 and 2) according to the present invention is shown.Fabrication tank100′″ includes substantially all of the same elements as the embodiment offabrication tank100″ described in reference to FIG. 4, except forreservoir120″. Instead of an integral reservoir, such asreservoir120″,fabrication tank100′″ includes adispenser120′″ for applyingunconsolidated material126, which is drawn from anexternal reservoir159′″, to afabrication substrate50. By way of example only,dispenser120′″ may comprise a laminar flow dispenser or a spray nozzle of a known type. A laminar flow dispenser is currently preferred for use asmaterial dispenser120′″, as laminar flow would result in the presence of fewer air bubbles inunconsolidated material126 than would be present ifunconsolidated material126 were sprayed ontofabrication substrate50 and, thus, eliminate the need for removing such bubbles. Additionally, when dispensed with a laminar flow dispenser,unconsolidated material126 may be applied toupper surface56 offabrication substrate50 without covering any structures that protrude therefrom (e.g., solder balls that protrude from a semiconductor device54), thereby eliminating the need to subsequently remove consolidated material orunconsolidated material126 from such structures.Dispenser120′″ may apply a predetermined quantity, or metered amount, ofunconsolidated material126 ontofabrication substrate50 to form asingle layer22 ormultiple layers22a,22b, etc. ofunconsolidated material126 thereon, which are to be sequentially dispensed and, possibly, sequentially consolidated.
• Of course, operation of[0098]dispenser120′″ may be controlled bycontroller700 or by aprocessing element105′″ (e.g., a processor smaller group of logic circuits) that is associated withfabrication tank100′″.
Material Consolidation System
• Various exemplary embodiments of material consolidation systems[0099]200 (FIGS. 1 and 2) that may be used in astereolithographic apparatus10 according to the present invention are shown in FIGS. 6 and 7.
• With reference to FIGS. 1 and 6, a[0100]stereolithographic apparatus10 that incorporates teachings of the present invention may include amaterial consolidation system200′ which is configured to direct a focused beam of consolidating energy, such as alaser beam220′, into achamber110 of afabrication tank100 and onto selected locations of asurface128 of avolume124 ofunconsolidated material126 which is exposed tochamber110.
• When a[0101]laser beam220′ is employed as the consolidating energy,material consolidation system200′ includes alaser210′ of a known type that generateslaser beam220′. By way of example only,laser210′ may include asource211′ which is configured to generate light in the ultraviolet (UV) range of wavelengths of electromagnetic radiation.Laser210′ may also include one ormore lenses216 to focus alaser beam220′ that has been emitted bysource211′ to a desired resolution. Alocation control element212′, such as a scan controller (e.g., a galvanometer) of a known type, may be associated withsource211′ oflaser210′ in such a way as to control the path of alaser beam220′ emitted fromsource211′ and, thus, to effect movement oflaser beam220′. The operation oflocation control element212′ and, thus, the movement of alaser beam220′, may be controlled bycontroller700 or a processing element205′ (e.g., a processor or smaller group of logic circuits) which is dedicated for use withlaser210′, in accordance with a CAD program and an accompanying CAD file for the object to be fabricated.
• It is well known that the resolution of a[0102]laser beam220′ that is to be moved may be substantially maintained by keeping the path oflaser beam220′ as constant (in this case, vertical) as possible. This may be done by increasing the path length of thatlaser beam220′ (e.g., to about twelve (12) feet). Nonetheless, it may not be practical for a stereolithographic apparatus10 (FIG. 1) that incorporates teachings of the present invention to include alaser210′ with asource211′ that is positioned a sufficient distance fromsurface128 ofvolume124 ofunconsolidated material126 that is to be selectively consolidated bylaser beam220′. Accordingly,laser210′ may also include asuitable mirror214′ or series ofmirrors214′ that results in a nonlinear path forlaser210′ to provide a desired path length L forlaser beam220′ in a fixed amount of available space. As depicted, the area ofmirror214′ may be large enough to substantially cover the entire cone of possible angles at whichlaser beam220′ may be directed bylocation control element212′ and, thus, to reflectlaser beam220′ from every possible direction onto a corresponding location ofsurface128.
• Optionally, or as an alternative to the use of a[0103]location control element212′, the position and/or orientation of one or more ofmirrors214′ may be moved, such as by anactuator215′ therefor (e.g., a motor). The operation ofactuator215′ and, thus, the movement of amirror214′ associated therewith, may be controlled bycontroller700.
• The size of the “spot ”[0104]222′ of alaser beam220′ that impinges onsurface128 ofunconsolidated material126 to consolidate (e.g., cure) the same may be on the order of about 0.001 inch to about 0.008 inch across. It is currently preferred that, whenlaser beam220′ is moved across surface128 (i.e., in the X-Y plane), the resolution oflaser beam220′ be ±0.0003 inch over at least a 0.5 inch×0.25 inch field from a predetermined center point C onsurface128, thereby providing a high resolution scan across an area of at least 1.0 inch×0.5 inch. Of course, it is desirable to have substantially this high a resolution across the entirety ofsurface128 to be scanned bylaser beam220′, such area being termed the “field of exposure.”
• FIG. 7 depicts another exemplary embodiment of[0105]material consolidation system200″, which is configured to direct unfocused, or blanket, consolidatingenergy220″ in the form of electromagnetic radiation (e.g., light or a light beam) into achamber110 of afabrication tank100 and onto asurface128 of avolume124 ofunconsolidated material126 which is exposed tochamber110.
• A[0106]source210″ of consolidatingenergy220″ may remain in a fixed position as consolidatingenergy220″ is introduced intochamber110 orsource210″ may be moved, such as by anactuation system217″ therefor. By way of example only, such anactuation system217″ may comprise an X-Y plotter of a known type, which may operate and, thus, movesource210″ under the direction of signals, or carrier waves, that have been transmitted bycontroller700 or by a processing element205″ (e.g., a processor or smaller group of logic circuits) that controls operation ofmachine consolidation system200″. Operation ofsource210″ may be under control of controller or processing element205″.
• Of course, when[0107]unconsolidated material126 is nonselectively consolidated by consolidatingenergy220″ fromsource210″, a machine vision system300 (FIGS. 1 and 2) is not employed at that time.
Machine Vision System
• With returned reference to FIG. 1, a[0108]stereolithographic apparatus10 according to the present invention that employs a material consolidation system200 (e.g.,material consolidation system200′ shown in FIG. 6) which selectively consolidatesmaterial126 may also include amachine vision system300. It is currently preferred that the field of vision ofmachine vision system300 be substantially coextensive with the field of exposure of alaser beam220′ (FIG. 6) or other consolidatingenergy220 employed by amaterial consolidation system200 to be used in conjunction withmachine vision system300.
• Examples of different types of[0109]machine vision systems300 that may be used in accordance with teachings of the present invention are illustrated in FIGS. 8 and 9.
• In FIG. 8, a scanning embodiment of[0110]machine vision system300′, or one which is configured to move relative to achamber110 of a fabrication tank100 (FIGS. 1 and 2) with which it is used, is depicted.Machine vision system300′ includes acamera310′ which may be carried and moved over afabrication substrate50 by ascan element312′.Scan element312′positions camera310′ in close proximity to (e.g., inches from) surface128 (FIG. 1) ofvolume124 of unconsolidated material126 (FIG. 1) so as to enablecamera310′ to view minute features on a fabrication substrate50 (e.g., bond pads, fuses, or other circuit elements of a semiconductor device) that is located at or nearsurface128. Upon viewingfabrication substrate50,camera310′ communicates information about the precise locations of such features (e.g., with an accuracy of up to about ±0.1 mil (i.e., 0.0001 inch)) to acomputer320′ ofmachine vision system300′.
• [0111]Camera310′ may comprise any one of a number of commercially available cameras, such as CCD cameras or CMOS cameras available from a number of vendors. Of course, the image resolution ofcamera310′ should be sufficiently high as to enablecamera310′ to view the desired features offabrication substrate50 and, thus, to enablecomputer320′ to precisely determine the positions of such features. In order to provide one or more reference points for the features that are viewed bycamera310′,camera310′ may also “view” one or morefiducial marks112 within a chamber110 (FIG. 1) of a fabrication tank100 (FIG. 1) with whichmachine vision system300′ is used.
• Suitable electronic componentry, as required for adapting or converting the signals, or carrier waves, that are output by[0112]camera310′, may be incorporated in aboard322′ installed in acomputer320′. Such electronic componentry may include one ormore processors324′, other groups of logic circuits, or other processing or control elements that have been dedicated for use in conjunction withcamera310′. At least oneprocessing element324′, which may include aprocessor324′, another, smaller group of logic circuits, or other control element that has been dedicated for use in conjunction withcamera310′, is programmed, as known in the art, to process signals that represent images that have been “viewed” bycamera310′ and respond to such signals.
• A self-contained machine vision system available from a commercial vendor of such equipment may be employed as[0113]machine vision system300′. Examples of such machine vision systems and their various features are described, without limitation, in U.S. Pat. Nos. 4,526,646; 4,543,659; 4,736,437; 4,899,921; 5,059,559; 5,113,565; 5,145,099; 5,238,174; 5,463,227; 5,288,698; 5,471,310; 5,506,684; 5,516,023; 5,516,026; and 5,644,245. The disclosure of each of the immediately foregoing patents is hereby incorporated herein in its entirety by this reference. Such systems are available, for example, from Cognex Corporation of Natick, Massachusetts. As an example, and not to limit the scope of the present invention, the apparatus of the Cognex BGA Inspection Package™ or the SMD Placement Guidance Package™ may be adapted for use in a stereolithographic apparatus10 (FIG. 1) that incorporates teachings of the present invention, although it is currently believed that the MVS-8000™ product family and the Checkpoint® product line, the latter employed in combination with Cognex PatMax™ software, may be especially suitable for use in the present invention.
• A response by[0114]computer320′ may be in the form of instructions regarding the operation of a material consolidation system200 (FIGS. 1 and 2), such as the selectively consolidatingmaterial consolidation system200′ shown in FIG. 6. These instructions may be embodied as signals, or carrier waves. By way of example only, such responsive instructions may be communicated tocontroller700 ofstereolithographic apparatus10,10′ (FIGS. 1 and 2, respectively) or directly to a processing element205′ (FIG. 6), such as a processor or group of processors, associated with a material consolidation system200 (FIGS. 1 and 2) (e.g.,material consolidation system200′ shown in FIG. 6) with whichmachine vision system300′ is used.Controller700 or control element205′ may, in turn, causematerial consolidation system200′ to operate in such a way as to effect the stereolithographic fabrication of one or more objects onfabrication substrate50 precisely at the intended locations thereof.
• Due to the close proximity of[0115]camera310′ to surface128 (FIG. 1), the field of vision ofcamera310′ is relatively small. In order to enablecamera310′ to view a larger area ofsurface128 than that which is “covered” by or located within the field ofvision camera310′, ascan element312′ of a known type is configured to traversecamera310′ over at least part of the area ofsurface128.Scan element312′ is also useful for movingcamera310′ out of the path of any selectively consolidating energy being directed towardsurface128. By way of example only,scan element312′ may comprise an X-Y plotter or scanner of a known type. Generally, an X-Y plotter or scanner includes an x-axis element313′ and a y-axis element315′ that intersect one another. As depicted,camera310′ is carried by both x-axis element313′ and y-axis element315′ and, thus, is positioned at or near the location where x-axis element313′ and y-axis element315′ intersect one another.
• X-axis element[0116]313′ and y-axis element315′ are both configured to move relative to and, thus, to positioncamera310′ at a plurality of locations over afabrication substrate50. Movement of x-axis element313′ is effected by anactuator314′ (e.g., a stepper motor and actuation system, such as a gear or wheel that moves x-axis element313′ along a track) that has been operatively coupled thereto, withactuator314′ being configured to cause x-axis element313′ to move laterally (i.e., perpendicular to the length thereof) along a y-axis. Y-axis element315′ is operatively coupled to anactuator316′ therefor, which is configured to cause y-axis element315′ to move laterally along an x-axis.Actuators314′ and316′ may be configured to move their respective x-axis element313′ and y-axis element315′ in a substantially continuous fashion or in an incremental fashion. Movement ofactuators314′ and316′ may be controlled by a processing element such ascomputer320′ or ascanning controller326′, such as a processor or smaller group of logic circuits, that is dedicated to operation ofscan element312′ and which may communicate withcomputer320′ in such a way as to providecomputer320′ with information as to the specific location ofcamera310′ relative to surface128 (FIG. 1).
• FIG. 9 shows an embodiment of[0117]machine vision system300″ that includes acamera310″ which is mounted or otherwise secured in a fixed position relative to surface128 and may be maintained in a fixed position relative to achamber110 of a fabrication tank100 (FIGS. 1 and 2) with whichmachine vision system300″ is to be used. By way of example only,camera310″ may be positioned in close proximity to amirror214′ ofmaterial consolidation system200′ (FIG. 6) or at any other location which will providecamera310″ with a substantially unobstructed field of vision that covers the areas within whichfabrication substrates50 may be located.
• Like[0118]camera310′, which is described in reference to FIG. 8,camera310″ may comprise a CCD camera, a CMOS camera, or any other suitable type of camera. Ascamera310″ is positioned farther away from afabrication substrate50 to be viewed thereby, however,camera310″ may have an effectively larger field of vision thancamera310′. Of course, suitable optical and/or digital magnification technology may be associated withcamera310″ to provide the desired level of resolution. Further, althoughcamera310″ may be locationally stationary, a suitable gimbals structure with rotational actuators may be employed to pointcamera310″ at a specific location in the field of exposure with little actual rotational movement. Thus,camera310″ may be used for both broad, or “macro,” vision and viewing and inspection of miniature features.
• While[0119]machine vision system300″ lacks a scan element, the remaining features thereof may be the same as and operate in the same or a similar manner to the corresponding features ofmachine vision system300′, which is described in reference to FIG. 8.
Cleaning Component
• Exemplary embodiments of cleaning[0120]components400 that may be used with astereolithographic apparatus10 that incorporates teachings of the present invention, shown in FIG. 1, are depicted in FIGS. 4, 10, and11.
• The embodiment of[0121]cleaning component400′ shown in FIG. 4 is configured to be used with afabrication tank100″ that is configured like the one shown in FIG. 4.Cleaning component400′ may include an initialmaterial removal component410′ which is configured to remove excessunconsolidated material126 from afabrication substrate50, anapplicator420′ which is configured to introduce one or more cleaning agents127 (e.g., water, solvents, detergents, etc.) onto at least an exposed surface offabrication substrate50, and a secondarymaterial removal component430′ that removes cleaningagents127 and any residualunconsolidated material126 fromfabrication substrate50.
• Initial[0122]material removal component410′ ofcleaning component400′ comprisessupport system130″ offabrication tank100″, as well asmaterial reclamation zone170″ ofchamber110″ andreceptacle172′, offabrication tank100″.Support system130″ and, in particular,actuation element146″ orrotation element148″ thereof, is configured to accelerate rotation of afabrication substrate50 carried thereby to a relatively high speed (e.g., about 50 to about 6,000 rpm) in such a way that anyunconsolidated material126 thereon will be forced therefrom under centrifugal force along substantially the same plane as that within whichfabrication substrate50 is located, intoreceptacle172″, and prevented from falling intoreservoir120″.
• Optionally, a[0123]protective cover175 may be positioned beneathsupport element132″ and oversurface128 ofvolume124 ofunconsolidated material126. Of course,protective cover175 is configured to be placed in the appropriate location in such a way as to avoid contact withpositioning element140″. Accordingly,protective cover175 may include two ormore sections175a,175b, one or more of which is configured to accommodatepositioning element140″ upon being moved into position. Eachsection175a,175bofprotective cover175 may, for example, be moved into position in a hinged fashion (i.e., about hinges177), as depicted, or by horizontally sliding eachsection175a,175binto position. In order to moveprotective cover175 into position, it may be operably coupled with an actuator176 (e.g., a motor). Operation ofactuator176 and, thus, movement ofprotective cover175 may be directed bycontroller700 or by aprocessing element178, such as a processor or smaller group of logic circuits, that is dedicated for use withcleaning component400′.
• As an alternative to forcing excess[0124]unconsolidated material126 which is removed fromfabrication substrate50 intoreceptacle172″ by rotating, or spinning,unconsolidated material126 may be caused to fall intoreservoir120″ and, thus, captured directly thereby.
• Once excess[0125]unconsolidated material126 has been substantially removed fromfabrication substrate50,positioning element140″ is moved to raisesupport element132″ frommaterial reclamation zone170″ to cleaningzone180″.
• By way of example only,[0126]applicator420′ may comprise a fixed or movable high-pressure spray nozzle or group of nozzles that form aspray head421′, which is in flow communication with asource422′ of cleaning agent127 (e.g., water, solvents forunconsolidated material126, detergents, etc.).Applicator420′ is configured to be oriented so as to direct one ormore cleaning agents127 intochamber110″ offabrication tank100″ and onto an exposed surface of afabrication substrate50 that is carried bysupport system130″ and located within cleaningzone180″ ofchamber110″.
• [0127]Applicator420′ may be located in a fixed position relative tofabrication tank100″ or carried by amovable element424′, such as a robotic arm, which is configured to positionapplicator420′ so as to orient the same towardfabrication substrate50, as depicted in FIG. 4.
• [0128]Controller700 or one or morededicated processing elements426′ (e.g., a processor, a smaller group of logic circuits, etc.) that communicate withcontroller700, may communicate withapplicator420′ and its associatedmovable element424′, if any. Accordingly, operation ofapplicator420′, including, without limitation, the orientation ofspray head421′ and the application of cleaningagent127 onto a surface offabrication substrate50, may be performed under the direction of eithercontroller700 or adedicated processing element426′.
• Like initial[0129]material removal component410′, secondarymaterial removal component430′ ofcleaning component400′ includessupport system130″ offabrication tank100″. In addition, secondarymaterial removal component430′ includes cleaningzone180″ andreceptacle182 thereof ofchamber110″.Support system130″ and, in particular,actuation element146″ orrotation element148″ thereof, is configured to accelerate rotation of afabrication substrate50 carried thereby to a sufficiently high speed (e.g., about 50 to about 6,000 rpm) so that anycleaning agents127 orunconsolidated material126 thereon will be forced therefrom along substantially the same plane as that within whichfabrication substrate50 is located, intoreceptacle172″, and prevented from falling intoreservoir120″.
• Optionally, positive air pressure, which may be supplied by use of a so-called “air knife,” such as that depicted and described in reference to FIG. 11, may be positioned over each[0130]fabrication substrate50 following the cleaning process to dry anyresidual cleaning agents127 therefrom.
• A variation of cleaning[0131]component400′ does not comprise part of afabrication tank100″ but, rather, is separate therefrom so as to completely avoid the potential for contamination ofunconsolidated material126 withinreservoir120″ with excessunconsolidated material126 being removed fromfabrication substrate50 with cleaningagents127.
• Turning now to FIG. 10, another exemplary embodiment of[0132]cleaning component400″ is depicted.Cleaning component400″ includes amaterial removal component410″ and awash element420″, as well as asupport element430″ upon which one ormore fabrication substrates50 are supported whilematerial removal component410″ and washelement420″ perform their intended tasks.
• [0133]Material removal component410″, which is positioned external tofabrication tank100″, may comprise one or more removal heads412″, through which either a negative pressure (e.g., a vacuum) or a positive pressure (e.g., about 30 psi (which is typically not sufficient to puncture the skin of an operator ofstereolithographic apparatus10,10′ ) or higher pressures may be used and delivered by a so-called “air knife”, such as that manufactured by Secomak Ltd. of Middlesex, United Kingdom, at a sufficient velocity to overcome the adhesion ofunconsolidated material126 fromfabrication substrate50 and, thus, removeunconsolidated material126 from fabrication substrate50) may be applied to afabrication substrate50. Eachremoval head412″ may be supported by apositioning element414″, such as a robotic arm.Positioning element414″ placesremoval head412″ in sufficient proximity to one or more surfaces of afabrication substrate50 so that a negative pressure (e.g., a vacuum) or positive pressure applied tofabrication substrate50 byremoval head412″ may respectively draw any excessunconsolidated material126 onfabrication substrate50 intoremoval head412″ or blow any excessunconsolidated material126 fromfabrication substrate50. Alternatively,support element430″ may be transported so as to movefabrication substrate50 in proximity to one or more removal heads412″.Material removal component410″ may be used in combination with a bulk removal process, such as tipping or inverting afabrication substrate50 to permitunconsolidated material126 to flow therefrom.
• As[0134]fabrication substrate50 is brought in proximity to washelement420″ or washelement420″ is brought into proximity tofabrication substrate50,support element430″ may remain secured tofabrication substrate50. As shown,wash element420″ may include one or more spray heads421″ that communicate with asource422″ of cleaningagent127 and which may be oriented to direct cleaningagent127 ontofabrication substrate50.
• Any[0135]cleaning agent127 that remains onfabrication substrate50 may be removed therefrom by way of one or more removal heads412″, which may include at least oneremoval head412″ that was used to remove excessunconsolidated material126 fromfabrication substrate50 or adifferent removal head412″.
• Another embodiment of[0136]cleaning component400′″ that may be used in astereolithography apparatus10,10′ (FIGS. 1 and 2, respectively) according to the present invention is shown in FIG. 11.Cleaning component400′″ includes atank440′″ which is at least partially filled with one ormore cleaning agents127 and within which one ormore fabrication substrates50 may be introduced, such as by the illustratedwafer boat450′″. Additionally,cleaning component400′″ may include anagitation system460′″, which facilitates the removal of residual unconsolidated material fromfabrication substrates50. By way of example only,agitation system460′″ may include a vertical agitation system, which repeatedly moves asupport452′″ upon whichwafer boat450′″ is carried up and down.
• As another alternative, a rotary wash system (not shown), such as that available from Semitool of Kalispel, Montana, may be used to remove any residual unconsolidated material from one or more fabrication substrates.[0137]
Material Reclamation System
• Again referring to FIGS. 4 and 10, an exemplary embodiment of[0138]material reclamation system500, shown in FIG. 1, is illustrated.
• As depicted in FIG. 4,[0139]material reclamation system500 includes acollection conduit510 which includes afirst end512 that communicates withreceptacle172″ ofcleaning component400′ so as to receive excessunconsolidated material126 which has been collected byreceptacle172″. When used with the embodiment ofcleaning component400″ that is shown in FIG. 10,first end512 ofcollection conduit510 communicates withmaterial removal component410″, such as a negative pressure head, so as to collect excessunconsolidated material126 that has been drawn intomaterial removal component410″.
• The opposite,[0140]second end514 ofcollection conduit510 communicates with eitherreservoir120′,120″, as shown, or anexternal reservoir158′ (FIG. 3C) in communication therewith. Accordingly,unconsolidated material126 may be returned toreservoir120′,120″, or158′ throughcollection conduit510.
• One or[0141]more filters530, which are configured to permit the passage ofunconsolidated material126 therethrough while trapping particulate contaminants that are larger than a selected size, may also be positioned along the length ofcollection conduit510 or at anend512,514 thereof.
• One or more pumps[0142]520 (e.g., peristaltic pumps) may communicate withcollection conduit510, each applying either a positive or negative pressure thereto, to facilitate the transport ofunconsolidated material126 therethrough, as well as the return ofunconsolidated material126 toreservoir120′,120″,158′ throughconduit510.
Calibration of the Programmed Material Consolidation Apparatus
• With returned reference to FIGS. 1, 2, and[0143]6, as well as with reference to FIG. 12, machine vision system300 (e.g., either a movablemachine vision system300′, such as that shown in FIG. 8, or a stationarymachine vision system300″, such as that shown in FIG. 9) may be used to calibratestereolithographic apparatus10,10′ and, more particularly, material consolidation system200 (e.g., the selectivematerial consolidation system200′ shown in FIG. 6) thereof. Various types of calibration may be effected, including, but not limited to, calibration of the position (X-Y) at which a selectively consolidating energy, such aslaser beam220′, impinges uponsurface128 ofvolume124 ofunconsolidated material126, calibration of the magnification ofmachine vision system300 and required movement of the selectively consolidating energy to effect fabrication of a structure of desired dimensions, and calibration of the “squareness” of a grid of locations at which the selectively consolidating energy impinges uponsurface128.
• The position at which selectively consolidating energy impinges upon[0144]surface128 may, by way example only, be calibrated by selectively consolidatingunconsolidated material126 at one or more calibration locations, each of which is referred to herein as a “reference pixel”750, onsurface128. Next, eachreference pixel750 is “viewed” bymachine vision system300 to locate the same relative to a reference grid (not shown), which may be stored in memory of eithercomputer320′ (FIG. 8) or controller700 (FIG. 1). The location at which eachreference pixel750 actually appears is then compared with theanticipated location750′ forreference pixel750.Material consolidation system200, the reference grid, or a combination of both may then be adjusted, as known in the art, to compensate for any difference betweenanticipated location750′ and the actual location ofreference pixel750.
• The magnification with which a movable[0145]machine vision system300′, such as that shown in FIG. 8, views objects that are located within or exposed tochamber110 may be determined by movingcamera310′ a fixed distance and determining the number ofreference pixels750 that are “viewed” (e.g., as changes in contrast sensed by camera310) ascamera310′ is moved. For example, ifcamera310′ is moved a linear distance of 10 mils (i.e., 0.010 inch) and twenty (20) pixel widths (e.g., ten (10) pixels, each positioned one pixel width apart from each other) are detected (e.g., as nineteen (19) changes, or transitions, in contrast),camera310′ is magnifying a viewed image by a value which equates to a 20:1 pixels-per-mil ratio. This process may then be repeated at least once to check the measured magnification ofcamera310′. Knowledge of the pixel-to-mil ratio is useful for controlling the movement of selectively consolidating energy, such as by controlling operation of alocation control element212′ (e.g., pulsing of a stepper motor that moves a galvanometer) that moves alaser beam220′ (FIG. 6).
• A calibration plate (not shown) of a known type, which, of course, is configured specifically for the type of apparatus to be calibrated, may be used to determine the magnification with which a fixed[0146]camera310″ ofmachine vision system300″, shown in FIG. 9, views objects that are located within or exposed tochamber110. The calibration plate, which is also referred to as a “prime standard,” includes features of known dimensions and locations. These known dimensions may be compared, as known in the art, with the image viewed bycamera310″ to determine the degree to which an image of these features is magnified or demagnified bycamera310″.
• The linearity with which selectively consolidating energy impinges upon[0147]surface128 across the field of exposure ofmaterial consolidation system200′ may be determined and calibrated by determining the actual locations760 (FIG. 13), particularly at the corners and edges of a rectangular field of exposure, at which selectively consolidating energy, such aslaser beam220′, impinges onsurface128. Theactual locations760 at which the selectively consolidating energy impinges6nsurface128 may then be compared tolocations760′ (FIG. 13) that are anticipated if the selectively consolidating energy were impinging onsurface128 in a linear path. Responsive to this comparison, movement of the selectively consolidating energy may be adjusted, or calibrated, in such a way as to increase the linearity of the path along which the selectively consolidating energy impinges onsurface128 and, thus, the accuracy with which the selectively consolidating energy impinges onsurface128, particularly at the corners and edges of the field of exposure. In the example of alaser beam220′, adjustments in the movement thereof may be effected by adjustments in the manner in whichlocation control element212′ (FIG. 6), such as a pair of galvanometers, are moved.
• With reference to FIG. 13, such linearity calibration may be effected by positioning light-[0148]sensitive elements770, such as phototransistors, CCD arrays, or CMOS arrays, at selected locations withinchamber110, such as at the fourcorners116 thereof and along theedges118 thereof, midway between twocorners116. Alternatively, a light-sensitive plate (not shown) of a known type (e.g., a large phototransistor, CCD array, or CMOS array) may be positioned withinchamber110 at an elevation which is substantially the same as that at which surface128 (FIG. 6) is to be maintained during stereolithographic fabrication. As another alternative,reference pixels750 may be formed by use ofmaterial consolidation system200′ (FIG. 6) and viewed bymachine vision system300,300′,300″ (FIGS. 1, 2,8, and9).
Use of the Programmed Material Consolidation Apparatus
• In reference again to FIGS. 1 and 2, as well as to FIG. 14, an example of the use of a programmed material consolidation apparatus, such as[0149]stereolithographic apparatus10,10′, that incorporates teachings of the present invention is described.
• In order to stereolithographically fabricate one or[0150]more objects20, corresponding data from the .stl files, which comprise a 3-D CAD simulation or model, resident in memory (e.g., random-access memory (RAM)) associated withcontroller700 are processed bycontroller700. The data, which mathematically represents the one or more objects to be fabricated, may be divided into subsets, each subset representing alayer22, or “slice,” of theobject20. The division of data may be effected by mathematically sectioning the 3-D CAD model into at least onelayer22, a single layer or a “stack” ofsuch layers22 representing theobject20. Each slice may be from about 0.0001 inch to about 0.0180 inch thick. A thinner slice promotes higher resolution by enabling better reproduction of fine vertical surface features of the object or objects to be fabricated.
• Before fabrication of a[0151]first layer22a of anobject20 is commenced, the operational parameters forapparatus10,10′ may be set to adjust the size (diameter if circular) of selectively consolidating energy (e.g.,laser beam220′ shown in FIG. 6), if such is used to at least partially consolidateunconsolidated material126.
• In addition,[0152]controller700 may automatically check and, if necessary, adjust by means known in the art the elevation, or level, ofsurface128 ofvolume124 ofunconsolidated material126 to maintain the same at an appropriate focal length forlaser beam220′. U.S. Pat. No. 5,174,931, the disclosure of which is hereby incorporated herein in its entirety by this reference, discloses an example of a suitable level control system. Alternatively, the height of amirror214′ (FIG. 6) that reflectslaser beam220′ onto an appropriate location ofsurface128 may be adjusted responsive to a detected elevation ofsurface128 to cause the focal point oflaser beam220′ to be located precisely atsurface128, although this approach is more complex.
• A[0153]support system130,130′,130″,130′″ upon which one or more fabrication substrates50 (e.g., semiconductor substrates52) are carried may then be submerged inunconsolidated material126 withinreservoir120,120′,120″ to a depth equal to the thickness of onelayer22 or slice of theobject20 to be formed so as to form alayer22′ ofunconsolidated material126 onfabrication substrate50. The elevation ofsurface128 may subsequently be readjusted, as required to accommodate any differences betweenunconsolidated material126 andconsolidated material126′. Alternatively, alayer22′ ofunconsolidated material126 may be disposed onto an exposedupper surface56 offabrication substrate50.
• A[0154]machine vision system300,300′,300″ (FIGS. 1 and 2,8, and9, respectively) may then be used to viewfabrication substrate50 and to identify each location thereof over which anobject20 is to be fabricated.
• [0155]Laser210′ (FIG. 6) may then be activated solaser beam220′ will scansurface128 ofvolume124 ofunconsolidated material126 so as to at least partially consolidate (e.g., polymerize to an at least semisolid state) the same, thereby defining boundaries of alayer22 ofobject20 and filling in solid portions thereof.Support system130,130′,130″ may then be lowered to lower fabrication substrate50 a distance that is substantially equal to the desired thickness of thenext layer22 ofobject20 to be fabricated thereover, and the selective consolidation process repeated, as often as necessary, layer by layer, until eachobject20 is completed. Of course, the number oflayers22 that are required to formobject20 may depend upon the height ofobject20 and the desired thickness for eachlayer22 thereof.Different layers22 of a stereolithographically fabricatedobject20 may have different thicknesses.
• If desired, an[0156]uppermost layer22U′ ofunconsolidated material126 may be planarized, for example, by use of aplanarizing element195, such as that described in reference to FIG. 4B.Planarizing elements195 are particularly useful when one ormore layers22′ ofunconsolidated material126 are dispensed overfabrication substrate50 rather than being formed thereover by submersion.
• With continued reference to FIG. 14, as well as to FIG. 7,[0157]unconsolidated material126 oflayer22′ may be consolidated with less selectivity by exposinglayer22′ tolaser beam220′ which has been emitted fromlaser210′ (not shown).
• Although the foregoing description contains many specifics, these should not be construed as limiting the scope of the present invention, but merely as providing illustrations of some of the presently preferred embodiments. Similarly, other embodiments of the invention may be devised which do not depart from the spirit or scope of the present invention. Moreover, features from different embodiments of the invention may be employed in combination. The scope of the invention is, therefore, indicated and limited only by the appended claims and their legal equivalents, rather than by the foregoing description. All additions, deletions, and modifications to the invention, as disclosed herein, which fall within the meaning and scope of the claims are to be embraced thereby.[0158]

Claims (65)

What is claimed:

1. A method for removing unconsolidated material from a substrate having at least one programmable material consolidation-fabricated feature thereon, comprising: directing pressure towards the unconsolidated material.

2. The method ofclaim 1, wherein directing comprises directing a positive pressure.

3. The method ofclaim 2, wherein directing the positive pressure comprises directing a positive pressure sufficient to reduce adhesion of the unconsolidated material to at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

4. The method ofclaim 2, wherein directing the positive pressure comprises directing a positive pressure sufficient to substantially remove the unconsolidated material from at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

5. The method ofclaim 1, wherein directing comprises directing a negative pressure.

6. The method ofclaim 5, wherein directing the negative pressure comprises directing a negative pressure sufficient to reduce adhesion of the unconsolidated material to at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

7. The method ofclaim 5, wherein directing the negative pressure comprises directing a negative pressure sufficient to substantially remove the unconsolidated material from at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

8. The method ofclaim 5, further comprising:

collecting unconsolidated material removed from at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

9. The method ofclaim 8, further comprising:

returning the unconsolidated material to a quantity of unconsolidated material to be used for subsequent programmable material consolidation fabrication.

10. The method ofclaim 9, further comprising:

filtering the unconsolidated material following the collecting and before or during returning the unconsolidated material.

11. The method ofclaim 1, further comprising:

cleaning residual unconsolidated material from at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

12. The method ofclaim 11, wherein cleaning comprises applying at least one cleaning agent onto at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

13. The method ofclaim 12, wherein applying comprises directing at least one cleaning agent onto at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

14. The method ofclaim 13, wherein directing comprises spraying the at least one cleaning agent onto at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

15. The method ofclaim 12, wherein applying comprises at least partially immersing the substrate in a quantity of the at least one cleaning agent.

16. The method ofclaim 15, wherein cleaning further comprises agitating at least one of the substrate and the at least one cleaning agent.

17. The method ofclaim 12, further comprising:

removing the at least one cleaning agent from at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

18. The method ofclaim 17, wherein removing comprises applying pressure to the unconsolidated material.

19. The method ofclaim 18, wherein applying pressure comprises applying positive air pressure.

20. The method ofclaim 18, wherein applying pressure comprises applying negative air pressure.

21. The method ofclaim 17, wherein removing comprises applying force to the unconsolidated material.

22. The method ofclaim 21, wherein applying force comprises applying a centrifugal force.

23. A method for removing unconsolidated material from a substrate having at least one programmable material consolidation-fabricated feature thereon, comprising:

applying force to the unconsolidated material.

24. The method ofclaim 23, wherein applying force comprises applying a centrifugal force to the unconsolidated material.

25. The method ofclaim 24, wherein applying centrifugal force comprises spinning the substrate.

26. The method ofclaim 23, wherein applying force comprises applying force sufficient to reduce adhesion of the unconsolidated material to at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

27. The method ofclaim 23, wherein applying force comprises applying force sufficient to substantially remove the unconsolidated material from at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

28. The method ofclaim 23, further comprising:

collecting unconsolidated material removed from at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

29. The method ofclaim 28, further comprising:

returning the unconsolidated material to a quantity of unconsolidated material to be used for subsequent programmable material consolidation fabrication.

30. The method ofclaim 29, further comprising:

filtering the unconsolidated material following collecting and before or during returning the unconsolidated material.

31. The method ofclaim 23, further comprising:

cleaning residual unconsolidated material from at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

32. The method ofclaim 31, wherein cleaning comprises applying at least one cleaning agent onto at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

33. The method ofclaim 32, wherein applying comprises directing at least one cleaning agent onto at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

34. The method ofclaim 33, wherein directing comprises spraying the at least one cleaning agent onto at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

35. The method ofclaim 32, wherein applying comprises at least partially immersing the substrate in a quantity of the at least one cleaning agent.

36. The method ofclaim 35, wherein cleaning further comprises agitating at least one of the substrate and the at least one cleaning agent.

37. The method ofclaim 32, further comprising:

removing the at least one cleaning agent from at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

38. The method ofclaim 37, wherein removing comprises applying pressure to the unconsolidated material.

39. The method ofclaim 38, wherein applying pressure comprises applying positive air pressure.

40. The method ofclaim 38, wherein applying pressure comprises applying negative air pressure.

41. The method ofclaim 37, wherein removing comprises applying force to the unconsolidated material.

42. The method ofclaim 41, wherein applying force comprises applying a centrifugal force.

43. The method ofclaim 42, wherein applying force to the unconsolidated material is effected a first location over the fabrication site.

44. The method ofclaim 43, wherein applying centrifugal force is effected at a second elevation over the fabrication site, the second elevation differing from the first elevation.

45. The method ofclaim 44, further comprising:

preventing introduction of the at least one cleaning agent into the fabrication site.

46. A method for cleaning unconsolidated material from a substrate having at least one programmable material consolidation-fabricated feature thereon, comprising:

applying at least one cleaning agent onto at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

47. The method ofclaim 46, wherein applying comprises directing at least one cleaning agent onto at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

48. The method ofclaim 47, wherein directing comprises spraying the at least one cleaning agent onto at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

49. The method ofclaim 46, wherein applying comprises at least partially immersing the substrate in a quantity of the at least one cleaning agent.

50. The method ofclaim 49, wherein cleaning further comprises agitating at least one of the substrate and the at least one cleaning agent.

51. The method ofclaim 46, further comprising:

removing the at least one cleaning agent from at least one of the substrate and the at least one programmable material consolidation-fabricated feature.

52. The method ofclaim 51, wherein removing comprises applying pressure to the unconsolidated material.

53. The method ofclaim 52, wherein applying pressure comprises applying positive air pressure.

54. The method ofclaim 52, wherein applying pressure comprises applying negative air pressure.

55. The method ofclaim 51, wherein removing comprises applying force to the unconsolidated material.

56. The method ofclaim 55, wherein applying force comprises applying a centrifugal force.

57. A method for recovering unconsolidated material from a substrate upon which at least one feature has been programmable material consolidation-fabricated, comprising:

collecting the unconsolidated material from the substrate; and

returning the unconsolidated material to at least one of a fabrication site and a reservoir in communication with the fabrication site.

58. The method ofclaim 57, wherein collecting includes applying a negative pressure to the substrate to remove the unconsolidated material therefrom.

59. The method ofclaim 57, wherein collecting includes introducing the unconsolidated material into a conduit.

60. The method ofclaim 59, wherein returning comprises transporting the unconsolidated material along the conduit.

61. The method ofclaim 60, wherein transporting is effected with at least one pump.

62. The method ofclaim 60, further comprising:

filtering the unconsolidated material before or during the returning.

63. The method ofclaim 57, wherein returning comprises applying pressure to the unconsolidated material.

64. The method ofclaim 63, wherein applying pressure comprise pumping the unconsolidated material.

65. The method ofclaim 57, further comprising:

filtering the unconsolidated material before or during the returning.

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