US20110097977A1 - Multiple-sided cmp pad conditioning disk - Google Patents

Abstract

A conditioning tool for restoring a used CMP polishing pad to an operable condition. The tool includes a base that attaches to a driven machine and has a surface from which a shoulder protrudes that receives a peripheral edge of a disk. The disk has two opposing surfaces, each of which is substantially planar and has abrasive mounted thereon. The disk's peripheral edge is held in place between the base shoulder and a ring that has a shoulder that is complementary to the disk's peripheral edge. The ring is fastened to the base with the abrasive of the first disk surface protruding through an aperture in the ring, and the opposing disk surface spaced from the base's surface. After the disk's first surface is worn, the disk can be turned around to expose the opposite surface's abrasive to a CMP pad.

Description

BACKGROUND OF THE INVENTION
• 1. Field Of The Invention
• This invention relates generally to methods and apparatuses related to the polishing of workpieces, such as semiconductor wafers, and particularly to an improved disk or other shape substrate for conditioning and restoring polishing pads used in such methods.
• 2. Description Of The Related Art
• The production of integrated circuits involves the manufacture of high quality semiconductor wafers. As well known in this industry, a surface that is flat (planar) to a high degree of precision is required on at least one side of the wafer to ensure that appropriate performance objectives are achieved. As the size of the circuit components decreases and the complexity of the microstructures involved increases, the requirement for high precision surface qualities of the wafers increases.
• This high precision surface is formed on semiconductor wafers by the polishing or planarization of semiconductor wafers. During this process, a polishing pad is rotated against a surface of the wafer in the presence of an abrasive slurry. The chemical components of the abrasive slurry react with one or more particular materials on the wafer being polished and aid the abrasive in removing portions of this material from the wafer's surface. The typical polishing pad comprises a blown polyurethane-based material such as the IC and GS series of pads available from Rohm and Haas. The hardness and density characteristics of the polishing pads are determined on the basis of the material of the workpiece (semiconductor wafer) that is to be polished.
• The following patents provide a broad discussion of chemical, mechanical planarization, which is referred to herein, and in the industry, as CMP: Arai et al. U.S. Pat. No. 4,805,348 issued February, 1989; Arai et al. U.S. Pat. No. 5,099,614 issued March, 1992; Karlsrud et al. U.S. Pat. No. 5,329,732 issued July, 1994; Karlsrud et al. U.S. Pat. No. 5,498,196 issued March, 1996; Karlsrud et al. U.S. Pat. No. 5,498,199 issued March, 1996; Cesna et al. U.S. Pat. No. 5,486,131 issued January, 1996; and Holzapfel et al. U.S. Pat. No. 5,842,912 issued Dec. 1, 1998. All of the foregoing patents are incorporated herein by reference.
• During continued use of the polishing pad in the CMP process, the rate of material removal from the wafer gradually decreases due to what is referred to in this field as “pad glazing”. Additionally, with continued use, the surface of the polishing pad normally experiences uneven wear which results in undesirable surface irregularities. Therefore, it is necessary to recondition (true and dress) the polishing pad to restore it to a desirable operating condition by exposing the pad to a pad-conditioning surface, such as the planar surface of a rotating disk, having suitable cutting elements on it. This truing and dressing of the pad may be accomplished during the wafer polishing process (referred to as in-situ conditioning) such as described in U.S. Pat. No. 5,569,062 issued on Oct. 29, 1996 to Karlsrud. However, such conditioning may also be done between polishing steps (referred to as ex-situ conditioning) such as described in U.S. Pat. No. 5,486,131 issued on Jan. 23, 1996 to Cesna et al., both of these patents being incorporated by reference herein.
• Reconditioning of a polishing pad restores the appropriate frictional coefficient of the pad surface and thereby allows the pad to continue to be used to provide the desired flat surface on the wafers. Reconditioning also allows effective transport of the polishing slurry to the wafer surfaces in order to obtain the most effective and precise planarization of the semiconductor wafer surface being polished.
• The typical pad conditioner comprises a stainless steel disk coated with a monolayer of abrasive particles. The disk is mounted to a rotary motor and the abrasive particle-coated surface is placed against the CMP pad when the surface is being rotated. Diamond particles or cubic boron nitride particles are the preferred abrasives, and are often referred to as “superabrasives” due to their resistance to wear. These superabrasive particles may be secured to the conditioning disk by electroplating, sintering or by a brazing process. The brazing process is preferred due to the formation of a stronger bond between the particles and the substrate, thereby resulting in the particles being less likely, compared to electroplated conditioning disks, to loosen and fall free. If abrasive particles fall free and become embedded in the polishing pad or are otherwise exposed to the wafer being polished, significant deformations in, or abrasions of, the wafer surface may occur that could cause the wafer to be unusable. Such a situation represents a loss of many thousands of dollars of time and labor.
• Conditioning disks employing a monolayer of braze bonded diamonds, such as those manufactured by Abrasive Technology, Inc. of Lewis Center, Ohio, have been recognized as very effective and an improvement over prior art conditioning disks using other bonding mediums, particularly in resisting premature loss of diamond abrasive particles. Current art for restoring used CMP polishing pad uses a diamond conditioning disk with a diamond surface on one side of the conditioning disk and a mounting surface on the opposite side of the disk to attach the conditioning disk to the conditioning drive mechanism.
• Some devices used for lapping, such as double-sided lapping, could appear to be related to devices used to restoring used CMP pads. Such devices, which are believed to be manufactured by Lap Master and possibly others, are inserted between oppositely-rotated platens and float therein during opposing rotation. Such devices are not driven directly as CMP reconditioning disks must be in typical CMP reconditioning processes due to the fact that CMP polishing pads recondition only one side of a surface at a time. CMP pads are not used to polish two sides of a surface as in the lapping process.
• Therefore, the need arises for a conditioning disk that reduces the amount of material used and thereby reduces the cost of the conditioning disk without any reduction in performance.
BRIEF SUMMARY OF THE INVENTION
• The invention provides a conditioning tool for restoring a used CMP polishing pad to an operable condition. In a preferred embodiment, the invention includes a substrate, which is preferably a disk having a circular peripheral edge. In a preferred embodiment, the peripheral edge of the disk is beveled with at least two surfaces at an angle with one another.
• The disk has a first substantially planar surface to which a first abrasive, such as a monolayer of diamond particles, is attached, such as by brazing. A second abrasive is attached in a similar manner to a second, opposing substantially planar surface. This configuration thereby forms two opposing, substantially planar abrasive surfaces that are used, at different times, for reconditioning a used CMP polishing pad.
• A base, which is for drivingly linking the tool to a rotatably driven machine, has a circular shoulder extending from a base surface. The base shoulder diameter is preferably substantially equal to a diameter of the circular peripheral edge of the disk. The base shoulder receives at least a portion of the peripheral edge of the disk, and most preferably receives one of the angled surfaces of the peripheral edge.
• A fastener, such as a screw or magnets, mounts the disk to the base. The first abrasive faces away from the base, and the second abrasive is spaced from the base surface so that no wear is experienced by either the second abrasive or the base surface due to contact.
• In a preferred embodiment, a ring has an annular body with a circular shoulder defining an aperture. The aperture has a diameter that is smaller than the diameter of the peripheral edge of the disk to prevent passage of the entire disk through the aperture. The ring shoulder diameter is substantially equal to the diameter of the peripheral edge of the disk, and the ring shoulder receives at least a portion of the peripheral edge of the disk.
• A fastener, such as a screw or magnets, mounts the ring to the base with the disk held between the ring and the base by a clamping force. The clamping force is preferably applied only to the peripheral edge of the disk by the ring shoulder and the base shoulder. The first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface so that no wear is experienced by either the second abrasive or the base surface due to contact.
• Thus, in one embodiment of the invention, the base has a disk mounted to it, wherein the disk has abrasive on two opposing sides. The disk is flipped around when the abrasive on one side approaches or reaches the end of its useful life. The disk can be mounted to the base by fastening means, which can include any useful fastener. In the preferred embodiment, the fastening means includes a ring that is slightly larger than the disk, with an aperture through which the abrasive on the disk protrudes, that clamps the disk between the ring and the base. In one particular embodiment, the disk has peripheral edges that are advantageously contacted by the ring and the base, thereby avoiding mounting contact with the abrasive portions of the disk. The peripheral edges of the disk and the receiving surfaces of the base and ring align and retain the disk.
• The invention thus effectively provides two useful abrasive conditioning surfaces per disk instead of the current industry standard practice of one, among other advantages and improvements.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
• FIG. 1 is a top view illustrating a preferred embodiment of the present invention.
• FIG. 2 is a bottom view illustrating a preferred embodiment of the present invention.
• FIG. 3 is a side view in section illustrating the embodiment ofFIGS. 1 and 2 through the line3-3 ofFIG. 1.
• FIG. 4 is a view in perspective illustrating the embodiment ofFIG. 3.
• FIG. 5 is a view in perspective illustrating the preferred disk of the present invention.
• FIG. 6 is a close-up view illustrating the disk ofFIG. 5.
• FIG. 7 is a view in perspective illustrating the preferred ring of the present invention.
• FIG. 8 is a side magnified view in section of the encircled portion of the preferred embodiment of the present invention shown inFIG. 3.
• FIG. 9 is a perspective view in section with the base removed to illustrate the notches in the disk and the ring.
• FIG. 10 is a top view of the invention shown inFIG. 9 showing the position of the complete key in the notches, which are only shown in part due to the section view.
• FIG. 11 is a view in perspective illustrating an alternative embodiment of the present invention.
• FIG. 12 is a side view in section illustrating the embodiment ofFIG. 11 in section through the line12-12.
• FIG. 13 is a perspective view in section illustrating the embodiment ofFIG. 11 in section through the line12-12.
• FIG. 14 is a perspective view in section illustrating the embodiment ofFIG. 11 in section through the line14-14.
• FIG. 15 is a view in perspective illustrating the device ofFIG. 14 with several pieces removed for illustrative purposes.
• FIG. 16 is a view illustrating the device ofFIG. 15 with additional pieces removed.
• FIG. 17 is a view illustrating the device ofFIG. 11 with several pieces removed for illustrative purposes.
• FIG. 18 is a view illustrating the device ofFIG. 17 with additional pieces removed.
• FIG. 19 is a view in perspective illustrating an alternative embodiment of the present invention.
• FIG. 20 is a view in perspective illustrating the embodiment ofFIG. 19 from the underside.
• FIG. 21 is a side view in section illustrating the embodiment ofFIG. 20 through the lines21-21.
• FIG. 22 is a perspective view in section illustrating the embodiment ofFIG. 20 through the lines21-21.
• FIG. 23 is a perspective view in section illustrating the embodiment ofFIG. 22 with several pieces removed for illustrative purposes.
• FIG. 24 is a view in perspective illustrating an alternative embodiment of the present invention.
• FIG. 25 is a side view in section illustrating an alternative embodiment of the present invention.
• FIG. 26 is another side view in section illustrating the embodiment ofFIG. 25 with portions removed for clarity.
• FIG. 27 is a lower section view in perspective illustrating the embodiment ofFIG. 25.
• In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word connected or terms similar thereto are often used. They are not limited to direct connection, but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art.
DETAILED DESCRIPTION OF THE INVENTION
• The preferred embodiment of the present invention includes the following major components that are illustrated inFIGS. 1-10. Aholder10 is made up of abase20 and aring30 that attaches to thebase20. Thebase20 is designed to be attached to a drive mechanism (not shown), such as a rotatable drive motor. Thering30 rigidly and firmly attaches to the base20 using fasteners, such as screws or magnets. Adisk40 is mounted between thering30 and thebase20, and is held in place in a tight, non-rotatable connection preferably by structures located at the peripheral edge of thedisk40 and thering30 orbase20 that interlock to prevent relative movement of thedisk40 and theholder10. In this manner, thedisk40 is held firmly in place in theholder10, and is driven rotatably thereby without substantial relative rotational movement between thedisk40 and theholder10. This permits the disk surface to be placed in contact with a CMP polishing pad for conditioning the pad, which is the purpose of the apparatus.
• The pad conditioning substrate, such as thedisk40 in particular, is best shown inFIGS. 2,3 and5 having a generally planar shape with two opposing, substantially planar major faces42 and44. Themajor surfaces42 and44 of the disk are preferably parallel and substantially flat for reasons that will become apparent below. Upon the planarmajor surfaces42 and44 an abrasive, and preferably conventional superabrasive particles, such as diamond, cubic boron nitride, silicon carbide, alumina or any other conventional superabrasive, is attached in a conventional manner, such as by brazing, electroplating or adhesively mounting as described in the United States patents incorporated herein by reference and as known conventionally. The abrasive particles are preferably about 30 to about 350 microns, depending upon the type of CMP the disk will be used for. Thus, these particles are not visibly distinct in the illustrations. The abrasive can be in a pattern, and can be over most of the surface of the major faces42 and44, or only over a small portion thereof, such as in the case of a ring-shaped circle of abrasive. Thus, each of the major faces42 and44 has at least a portion of its surface covered by a single layer of abrasive to enable thefaces42 and44 to abrade any workpiece surface against which they are placed in contact during rotation.
• Because thedisk40 can be used as a CMP pad conditioning disk, the portion of thefaces42 and44 that is covered by abrasive does not extend to the peripheral edge of thedisk40. Instead, according to industry practice, a small gap is formed between the radially outermost edge of the abrasive and the extreme peripheral edge of thedisk40.
• Thedisk40 is preferably made of a strong, corrosion-resistant material, such as stainless steel, titanium, ceramic or plastic and has substantial thickness, on the order of 5.0 mm, to prevent substantial deformation when in use. The diameter of thedisk40 can be on the order of 10.5 cm. These sizes and materials are examples for the purpose of explanation; the size and material of the disk are not critical and can vary substantially from these examples. Preferably thebase20 and thering30 are also made of stainless steel or any other material that is compatible with the circumstances.
• As best viewed inFIG. 6, the disk'speripheral edge45 is preferably beveled to form threecircular surfaces46,48 and49 extending around the periphery of thedisk40 and formed at angles with one another. The relative angle α between the twosurfaces46 and48 is not critical, but is preferably in the range of about 90 degrees. The circular surfaces46 and48 are preferably angled relative to thesurfaces42,44 and49 of thedisk40 by about 45 degrees, and thesurface49 is angled relative to themajor surfaces42 and44 by about 90 degrees. These angles can vary significantly. For example, the angle α can vary from 90 degrees, and it is contemplated that the angle α can range from at least about 30 degrees to about 180 degrees.
• When the angle α is 180 degrees, theperipheral edge45 is flat; that is, theedge45 defines a single curved, circular surface angled at ninety degrees from themajor surfaces42 and44 of the disk. Although this embodiment is not illustrated, such a disk has a configuration resembling a conventional coin. In anotheralternative disk340 shown inFIG. 24, theperipheral edge345 is rounded. Other shapes are also contemplated. The peripheral edge of the disk can be any non-perpendicular shape that protrudes to permit gripping, and with some fastening means, a perpendicular shape is useful. Virtually any shape that permits the invention to function as described herein can be substituted for the peripheral edge shapes described herein.
• Thebase20 is shown inFIG. 1 having a substantially circular cylindrical configuration. This is preferred, but not required, and it will become apparent to the person of ordinary skill that the base20 can be any shape that can be driven in rotation, preferably at high speed, without imbalance and without negatively affecting surrounding structures. Thebase20 has afirst end22 in which are formed voids, such as the threaded bores23, that permit convenient attachment of a drive mechanism, as is conventional. Examples of typical CMP conditioning machines used in the industry are the AMAT Mirra and Reflection tools and CMP machines sold by Ebarra Technologies. Other drive mechanisms can be substituted with modifications to the base and/or the drive mechanism that will be understood by the person having ordinary skill. Thebase20 is preferably mounted to the drive mechanism using screws (not shown) threaded into thebores23, although other fasteners will become apparent to the person having ordinary skill, including without limitation, a conventional tool “chuck” that radially grips a shaft, a magnetic attachment or an o-ring that is compressed and then expands into an annular groove.
• A second base end24 (seeFIGS. 3 and 4), which is opposite thefirst base end22 to which the drive mechanism mounts, has afirst surface25 that is preferably substantially planar. Ashoulder26 is formed integrally with the base20 (seeFIG. 8), although it could be mounted on thefirst surface25 as a separate piece. Theshoulder26 has an inwardly facingsurface28 that is angled at about 45 degrees from thefirst surface25. The inwardly facingsurface28 is of a size, shape and orientation to abut theangled surface46 of the disk'speripheral edge45, as shown inFIG. 8.
• Thering30 has acircular body31 with anaperture35 formed through thebody31. Theaperture35 is defined by the radially inwardly extendingshoulder36 that is most easily seen inFIG. 8. Theshoulder36 has asurface38 that is oriented from thesurface39 at an angle of about 45 degrees. Theaperture35 extends between the radially inward-most edge of theshoulder36, and is preferably slightly smaller in diameter than the diameter of thedisk40 so that thedisk40 cannot pass completely through theaperture35.
• Thering30 mounts to thebase20 by at least one fastener, such as thescrews32,33 and34, shown inFIG. 1. The screws32-34 extend through the aligned apertures extending between thering30 and thebase20, an example of which is theaperture50 shown inFIG. 8. When thering30 is mounted to thebase20, as shown in detail inFIG. 8, thedisk40 is clamped between thering30 and the base20 as will now be described.
• It is preferred that when thedisk40 is clamped between the base20 and thering30, the only surfaces in contact between the three respective bodies are the surfaces at the periphery of thedisk40 as shown clearly inFIG. 8. Thus, thesurface28 of thebody20 firmly abuts thesurface46 of thedisk40. Thesurface38 of thering30 applies an opposing abutting force against thesurface48 of thedisk40. The clamping force of thering30 and the base20 against the peripheral edge surfaces of thedisk40 retains thedisk40 in place in such firm engagement that no substantial movement of thedisk40 relative to theholder10 is possible under contemplated conditions when theholder10 is driven in rotation. Furthermore, the engagement of the beveledperipheral edge45 of thedisk40 with the complementary surfaces of thebase20 andring30 ensure that, even if thedisk40 is not initially resting in such a position, the fastening of thering30 to the base20 causes the angled surfaces of thedisk40 to slide against the abutting surfaces until thedisk40 “seeks” the relative position between the two structures in which thedisk40 is as close to the base20 as possible.
• Thedisk40 is also restricted from moving rotationally relative to theholder10 by a key57 that extends into the alignednotches37 and47 (seeFIGS. 6,7 and10) formed in thering30 and theperipheral edge45 of thedisk40, respectively. As shown inFIG. 9, thenotches37 and47 align with one another to form a void that is substantially the same shape as the key57. The key57 is preferably slightly smaller than thenotch47, and slightly larger than thenotch37 so that the key57 is inserted into and held in thenotch37 with a friction fit. The key57 thus remains attached to thering30, and extends into thenotch47 of thedisk40 upon alignment of thenotch47 with the protruding portion of the key57. Thedisk40 can then be removed by manually lifting thedisk40 from thebase20 andring30.
• It should be understood that although the invention shows asingle key57, it is contemplated that more than one such key can be used, and that the shape of the key can be varied from that shown. For example, the key can be circular, rectangular, triangular, dovetail or any other shape that is suitable. In an alternative embodiment, the key57 is replaced by a magnet that has such strong attraction to the disk itself, or a structure mounted in the disk or another structure, that any expected rotational force applied to thedisk40 by the workpiece is insufficient to cause relative motion.
• A gap60 (FIG. 8) is formed between themajor disk surface42 and thesurface25 on thebase20. Thegap60 prevents the abrasive on themajor disk surface42 from contacting thesurface25 on thebase20, and thereby causing wear between the two parts. Furthermore, themajor disk surface44 protrudes through theaperture35 of thering30, and extends past theextreme surface39 of thering30, as best viewed inFIG. 8. The extension of themajor disk surface44 past thering surface39 prevents thering30 from contacting the surface that is to be conditioned by the abrasive on themajor disk surface44.
• The invention operates in a preferred embodiment in the following manner. Thebase20 is mounted to the driving machine and thedisk40 is placed in thering30. Thering30 and thedisk40 are placed under the base20 (with thenotch47 aligned with thenotch37 and the key57 inserted in thenotches37 and47 as described herein) and the screws32-34 are inserted and tightened in the apertures. Upon tightening, thedisk40 is clamped in place between thering30 andbase20, and the angledperipheral surfaces46 and48 are seated against theangled surfaces28 and38 of thebase20 andring30, respectively.
• Once thedisk40 is mounted to theholder10, theholder10 and thedisk40 are rotated. The rotatingmajor disk surface44 is seated against one or more CMP polishing pads and the CMP pads are reconditioned as is conventional. Once the abrasive on themajor disk surface44 reaches a predetermined degree of wear, the rotating machine is halted and thering30 is removed from the base20 by removing the screws32-34 and manually pulling thering30 and thedisk40 away from thebase20, typically as a combination. Once thering30 anddisk40 are removed from thebase20, thedisk40 can be removed manually from thering30 by simply pulling thedisk40 away from thering30.
• The removeddisk40 is then flipped so that the wornmajor disk surface44 faces toward thebase20 and the freshmajor disk surface42 faces away from thebase20. Of course, the entire apparatus, including the disk, can first be cleaned, if necessary. In one contemplated embodiment, a film, coating or other indicator of whether a major disk surface has been used is fixed to the surface to make instantly recognizable whether themajor disk surface42 has been used. The disk'snotch47 is aligned with thenotch37 and key57, and thering30 is then reattached to the base20 in the same way it was attached previously. This forms a gap between themajor disk surface44 and thebase surface25 that is essentially identical to thegap60. Theholder10 and thedisk40 are rotated and themajor disk surface42 is seated against one or more CMP polishing pads so the CMP pads can be reconditioned.
• The invention permits only one abrasive surface of thedisk40 to be used at any time. This is due to the fact that theholder10 substantially covers all other sides of thedisk40 when thedisk40 is being rotated in contact with a workpiece. Furthermore, because of thegap60, the use of one abrasive surface has little to no effect on the opposing abrasive surface, because little to no wear occurs to the abrasive surface that is not in use or to its adjacent structure.
• It will become apparent from the description herein that various substitutes can be made for the preferred structures and methods described herein. For example, the fasteners used to mount thering30 to the base20 are preferably screws, because screws facilitate the removal and replacement of thedisk40 from the base20 numerous times using common tools. However, other removable fasteners can be used instead of the screws32-34, including without limitation, magnetic fasteners, rivets, clamps and specialized structures made for the purpose of fastening the ring to the base or any combination of these or equivalents. Similarly, although thebase20 is shown attached to the driving machine by threadedapertures23 formed therein, the person having ordinary skill knows that such fastening means can likewise be replaced by a single threaded chuck, clamps, and other fastening means. Furthermore, sealing structures can be added to prevent the slurry from leaking into theholder10. For example, compressible O-rings or adhesive-backed plastic gaskets can be inserted between thering30 and thebase20, as well as between thedisk40 and thebase20 and between other structures.
• In addition, the shape of thedisk40,ring30 andbase20 can be modified from the preferred embodiment shown inFIGS. 1-9. For example, the base can be square or triangular in section rather than circular. Similarly, the ring and disk can have different shapes, preferably to accommodate the shape of the cooperating components, and to permit rotation of the holder and disk without excessive vibration.
• One distinct advantage of the invention is that it is manufactured to be very similar in material and size to existing one-sided disks, and therefore can be used in existing machines, but there is abrasive on both sides instead of only one side. This permits the subsequent use of a second side of the disk without substantial added material costs in the underlying substrate (disk). Similarly, the only portion of the abrasive device that must be either discarded or recycled after use is the component that seats directly against the surface to be abraded. Because theholder10 is re-used, costs over conventional one-sided disks are lower in the long term.
• Another advantage of the invention is the reduced time required to change a disk. Theholder10 does not have to be removed from the machine that drives the holder. Instead, the holder remains in the driver and a few small screws are removed and then replaced after rotation of the disk to expose the unused side. Still further, when it is desired to expose a new abrasive surface in any holder that is using a disk with an unused abrasive surface, this can be accomplished without having to locate another disk. Instead, a fresh disk is retained within theholder10.
• It is also contemplated that instead of a disk with only two sides, other substrate shapes can be used. For example, a stainless steel cube is contemplated having six planar sides and between two and six abrasive surfaces. Each side has a monolayer of superabrasive extending to near the edges thereof. A base has a shoulder with a square-shaped surface that seats against the cube. A square ring with a similar shoulder around an aperture that is slightly smaller than each of the cube's sides is mounted to the base, thereby clamping the cube to the base. The base, ring and cube are mounted to a device that rotates the combination and the protruding surface of the cube abrades the workpiece. Upon reaching a certain point of wear, the cube is removed and moved to expose a different, unused abrasive surface of the cube through the aperture in the ring by removing the ring and then replacing the ring after movement of the cube. Alternative shapes are also contemplated.
• The abrasive characteristics of each side of a substrate are preferably substantially the same. However, it is contemplated that the abrasive on one side can differ slightly or substantially from the abrasive on the opposing side. Additionally, with a multi-sided substrate each side can differ so that, for example, each abrasive can be used for a portion of a polishing procedure on a workpiece. In a contemplated example, a coarse abrasive is used first, and then a more fine abrasive, and then a still finer abrasive.
• Another alternative embodiment of the invention is shown inFIGS. 11-18. InFIG. 11, aholder110 is made up of abase120 and aring130 that attaches to thebase120. Thebase120 is designed to be attached to a drive mechanism (not shown), such as a rotatable drive motor. Thering130 rigidly and firmly attaches to the base120 using fasteners, such as screws or magnets. Adisk140 is mounted to thering130, and held in place in a tight, non-rotatable connection preferably by structures located at the peripheral edge of thedisk140 and thering130 orbase120 that interlock to prevent relative movement of thedisk140 and theholder110. In this manner, thedisk140 is held firmly in place in theholder110, and is driven rotatably thereby without substantial relative rotational movement between thedisk140 and thebase120.
• Thedisk140 is substantially the same as thedisk40 shown and described herein. Thebase120 is shown inFIG. 11 having a substantially circular cylindrical configuration, which is preferred. Thebase120 has a first end122 (seeFIG. 12) in which are formed voids, such as the threaded bores, that permit convenient attachment of a drive mechanism, as is conventional. Thebase120 is preferably mounted to the drive mechanism in a conventional manner.
• A second base end124 (seeFIG. 12), which is opposite thefirst base end122 to which the drive mechanism mounts, has afirst surface125 that is preferably substantially planar. Thering130 has a circular body with an aperture formed through the body. The aperture is defined by theshoulder136 that forms a disk-shaped void that seats against the peripheral edge of thedisk140. Theshoulder126 of thering130 opposes theshoulder136 and forms a groove therebetween into which the peripheral edge of thedisk130 is inserted during use. The aperture135 extends between the radially inward-most edge of theshoulder136, and is preferably slightly smaller in diameter than thedisk140 so that thedisk140 cannot pass completely through the aperture135. Thus, theshoulders126 and136 of thering130 form surfaces that seat against the peripheral edge of thedisk140 much like theshoulders26 and36 of the embodiment shown inFIGS. 1-10. However, because theshoulders126 and136 are not moveable relative to one another, there is not a similar adjustable clamping, and there must be separable portions of the ring to permit insertion and removal of thedisk140.
• Thering130 mounts to thebase120 by at least one fastener, such as thescrews132, and134, shown inFIG. 11. It is preferred that when thedisk140 is mounted in thering130, the only surfaces in contact between the three respective bodies are the surfaces at the periphery of thedisk140 as with the embodiment ofFIGS. 1-10. In order to mount thedisk140 in thering130, thefirst portion130a(seeFIGS. 15 and 16) is separated from the second portion130b, such as by removing fasteners from voids in the ends of theportions130aand130b. Thus, the second portion130bcan be mounted permanently to thebase120, thedisk140 slid into the groove defined by theshoulders136 and126, thefirst portion130ais slid over the end of thedisk140, and then thefasteners132 and134 are fixed between the base120 and thering130.
• Thedisk140 is restricted from moving rotationally relative to theholder110 by a key157 (seeFIGS. 13,17 and18) that extends into aligned notches formed in thering130 and the peripheral edge of thedisk140. A gap160 (FIG. 12) is formed between themajor disk surface142 and thesurface125 on thebase120. Thegap160 prevents the abrasive on themajor disk surface142 from contacting thesurface125 on thebase120, and thereby causing wear between the two parts. Thus, theholder110 has many of the same features of the embodiment ofFIGS. 1-10, thereby demonstrating the variability of the embodiments of the present invention.
• Another alternative embodiment of the invention is shown inFIGS. 19-23. Theholder210, which attaches to a drive mechanism as with the other embodiments disclosed herein, has adisk240 attached to abase220 by fastening means, such as thescrews232 and234, as shown inFIG. 21. Of course, other fasteners and fastening means could be substituted for thescrews232 and234, including without limitation magnets, press-fit pins, rivets and clamps or a combination. For example, a contemplated combination includes a magnetic attraction between a disk and base combined with one or more drive pins that extend from the base into corresponding voids in the disk to prevent relative rotation. Abase surface225, which is preferably planar, is formed on one end of thebase220. A first disk-receiving surface is formed on theshoulder236 extending from thesurface225. A second disk-receiving surface is formed on anopposing shoulder226. Complimentary surfaces are formed on thedisk240 at the peripheral edge thereof and at the transition between thecentral region250 and theabrasive surface252.
• When thedisk240 is mounted to thebase220, these complimentary surfaces permit theshoulders236 and226 of the base220 to contact thedisk240 where there are no abrasive particles. Thus, when thescrews232 and233 are tightened against thecentral region250 of thedisk240, the opposite side of thedisk240 seats against thebase220, but a gap is formed between the abrasive surface and the disk'ssurface225. Of course, the peripheral edge of thedisk240 need not be beveled. Instead, the peripheral edge can be angled at90 degrees from the major surfaces of the disk.
• Another alternative embodiment of the invention is shown inFIGS. 25-28. InFIG. 25, aholder410 is made up of abase420 and aring430 that attaches to thebase420. Thebase420 is designed to be attached to a drive mechanism (not shown). Thering430 rigidly and firmly attaches to the base420 using fasteners, such as screws or magnets (not shown). Adisk440 is mounted to thering430, and held in place in a tight, non-rotatable connection preferably by structures located at the peripheral edge of thedisk440 and thering430 orbase420 that interlock to prevent relative movement of thedisk440 and theholder410. In this manner, thedisk440 is held firmly in place in theholder410, and is driven rotatably thereby without substantial relative rotational movement between thedisk440 and thebase420. Thedisk440 is substantially the same as thedisk40 shown and described herein, except for the peripheral edges.
• As best viewed inFIGS. 25 and 26, thedisk440 has aperipheral edge445 that is beveled to form threecircular surfaces446,448 and449 extending around the periphery of thedisk440 and formed at angles with one another. The relative angle between the twosurfaces446 and448 is not critical, but is preferably in the range of about 90 degrees. Thesurfaces446 and448 are preferably angled relative to the opposing disk surfaces442 and444 and theperipheral edge surface449 of thedisk440 by about 45 degrees. Furthermore, thesurface449 is angled relative to thesurfaces442 and444 by about 90 degrees. These angles can vary significantly as with the embodiments described above.
• Thebase420 is shown inFIG. 25 having a substantially circular cylindrical configuration, which is preferred. Thebase420 has a first end in which are formed voids, such as the threaded bores, that permit convenient attachment of a drive mechanism, as is conventional. Thebase420 is preferably mounted to the drive mechanism in a conventional manner. A base end424 (seeFIG. 25), which is opposite the base end to which the drive mechanism mounts, has afirst surface425 that is preferably substantially planar.
• Thering430 has a circular body with an aperture formed through the body. The aperture is defined by theshoulder436 that forms a disk-shaped void that seats against theperipheral edge449 of thedisk440. Theshoulder436 defines a rib that is inserted in the groove, formed at the peripheral edge of thedisk430, during use (as shown inFIG. 25). The aperture in thering430 extends between the radially inward-most edge of theshoulder436, and is preferably slightly smaller in diameter than thedisk440 so that thedisk440 cannot pass completely through the aperture. Thus, theshoulder436 forms a surface that seats against theperipheral edge445 of thedisk440 much like theshoulders26 and36 of the embodiment shown inFIGS. 1-10. However, because there is not a similar adjustable clamping as in theFIGS. 1-10 embodiment, there must be separable portions of thering430 to permit insertion and removal of thedisk440.
• Thering430 mounts to thebase420 by at least one fastener, such as screws (not illustrated). It is preferred that when thedisk440 is mounted in thering430, the only surfaces in contact between the three respective bodies are the surfaces at the periphery of thedisk440 as with the embodiment ofFIGS. 1-10. In order to mount thedisk440 in thering430, thefirst portion430a(seeFIG. 28) is separated from thesecond portion430b, such as by removing fasteners from voids in the ends of theportions430aand430b. Thus, thesecond portion430bis mounted permanently (or removably) to thebase420, thedisk440 is slid into thering portion430b, thefirst portion430ais slid over the end of thedisk440, and then the fasteners are fixed between the base420 and thering430.
• Thedisk440 is restricted from moving rotationally relative to theholder410 by a key457 (seeFIG. 25) that extends into aligned notches formed in thering430 and the peripheral edge of thedisk440. A gap460 (FIG. 25) is formed between themajor disk surface442 and thesurface425 on thebase420. Thegap460 prevents the abrasive on themajor disk surface442 from contacting thesurface425 on thebase420, and thereby causing wear between the two parts.
• This detailed description in connection with the drawings is intended principally as a description of the presently preferred embodiments of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the designs, functions, means, and methods of implementing the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and features may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention and that various modifications may be adopted without departing from the invention or scope of the following claims.

Claims (25)

1. A conditioning tool for restoring a used CMP polishing pad to an operable condition, comprising:

(a) a substrate having a peripheral edge and a first substantially planar major surface with a first abrasive mounted thereon and at least a second, oppositely facing, substantially planar major surface with a second abrasive mounted thereon;

(b) a base for drivingly linking to a rotatably driven machine, the base having a base surface; and

(c) at least one fastener mounting the substrate to the base with the second abrasive spaced from the base surface to form a gap between the base surface and the second abrasive, and the first abrasive facing away from the base.

2. The conditioning tool in accordance withclaim 1, wherein said at least one fastener is mounted at a central region of the substrate and the base, wherein said central region of the substrate has no abrasive mounted thereon.

3. The conditioning tool in accordance withclaim 2, wherein said at least one fastener extends through the substrate into the base.

4. The conditioning tool in accordance withclaim 1, wherein the substrate is a disk with a circular peripheral edge.

5. The conditioning tool in accordance withclaim 4, wherein said at least one fastener mounts a ring to the base with the disk held between the ring and the base by a clamping force applied to the disk, the first abrasive protrudes through an aperture of the ring that is smaller than the disk, the base has a first substrate-shaped void in which the substrate is mounted and the ring has a second substrate-shaped void in which the disk is mounted.

6. The conditioning tool in accordance withclaim 5, wherein the first substrate-shaped void is defined by a circular shoulder extending from the base surface, a shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk.

7. The conditioning tool in accordance withclaim 6, wherein the second substrate-shaped void is defined by a ring body having a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk.

8. The conditioning tool in accordance withclaim 7, wherein said at least one fastener mounts the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder.

9. The conditioning tool in accordance withclaim 8, further comprising a key inserted into notches formed in the disk and at least one of the ring and the base for preventing relative movement of the disk and the base.

10. The conditioning tool in accordance withclaim 4, wherein said at least one fastener mounts a ring to the base, a groove in the ring defining first and second substrate-shaped voids retains the disk in the ring, and the first abrasive protrudes through an aperture of the ring that is smaller than the disk.

11. The conditioning tool in accordance withclaim 10, wherein the first substrate-shaped void is defined by a first circular shoulder formed in the ring, a first shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk, and wherein the second substrate-shaped void is defined by a second circular shoulder formed in the ring opposing the first circular shoulder and defining an aperture having a diameter that is smaller than the diameter of the circular peripheral edge of the disk, the second circular shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk.

12. The conditioning tool in accordance withclaim 11, wherein the ring further comprises a first ring portion removably mounted to a second ring portion and configured to receive the disk.

13. The conditioning tool in accordance withclaim 12, further comprising a key inserted into notches formed in the disk and the ring for preventing relative movement of the disk and the base.

14. An improved conditioning tool for restoring a used CMP polishing pad to an operable condition including a disk with a circular peripheral edge and a first substantially planar surface to which a first abrasive is attached and a drive mount for drivingly linking to a rotatably driven machine, the improvement comprising:

(a) the disk having a second, opposing substantially planar surface to which a second abrasive is attached, thereby forming two opposing, substantially planar abrasive surfaces;

(b) a base on which the drive mount is formed, the base having a circular shoulder extending from a base surface substantially opposite the drive mount, a base shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk;

(c) a ring having an annular body with a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk; and

(d) at least one fastener mounting the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder, wherein the first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface.

15. The conditioning tool in accordance withclaim 14, wherein said at least one fastener mounts the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder.

16. The conditioning tool in accordance withclaim 15, further comprising a key inserted into notches formed in the disk and at least one of the ring and the base for preventing relative movement of the disk and the base.

17. A conditioning tool for restoring a used CMP polishing pad to an operable condition, comprising:

(a) a disk having a circular peripheral edge, a first substantially planar surface to which a first abrasive is attached and a second, opposing substantially planar surface to which a second abrasive is attached, thereby forming two opposing, substantially planar abrasive surfaces, the circular peripheral edge including a first surface and a second surface;

(b) a base for drivingly linking to a rotatably driven machine, the base having a circular shoulder extending from a base surface, a shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk and receiving the first surface of the peripheral edge of the disk;

(c) a ring having an annular body with a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving the second surface of the peripheral edge of the disk; and

(d) at least one fastener mounting the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder, wherein the first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface.

18. The conditioning tool in accordance withclaim 17, wherein said at least one fastener mounts the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder.

19. The conditioning tool in accordance withclaim 18, further comprising a key inserted into notches formed in the disk and at least one of the ring and the base for preventing relative movement of the disk and the base.

20. A conditioning tool for restoring a used CMP polishing pad to an operable condition, comprising:

(a) a substrate having a peripheral edge and a first substantially planar major surface with a first abrasive mounted thereon and at least a second, oppositely facing, substantially planar major surface with a second abrasive mounted thereon;

(b) a base for drivingly linking to a rotatably driven machine, the base having a base surface; and

(c) means for mounting the substrate to the base with the second abrasive spaced from the base surface to form a gap between the base surface and the second abrasive, and the first abrasive faces away from the base.

21. The conditioning tool in accordance withclaim 20, wherein the substrate is a disk with a circular peripheral edge.

22. A method of restoring a used CMP polishing pad to an operable condition, the method comprising:

(b) drivingly linking a base to a rotatably driven machine, the base having a circular shoulder extending from a base surface, a shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk;

(a) disposing a circular peripheral edge of a disk against the base's shoulder, the disk having a first substantially planar surface to which a first abrasive is attached and a second, opposing substantially planar surface to which a second abrasive is attached, thereby forming two opposing, substantially planar abrasive surfaces; and

(c) mounting a ring to the base, the ring having an annular body with a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving at least a portion of the peripheral edge of the disk;

(d) clamping the disk between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder, wherein the first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface.

23. The method in accordance withclaim 22, further comprising inserting a key into notches formed in the disk and at least one of the ring and the base for preventing relative movement of the disk and the base.

24. A conditioning tool for restoring a used CMP polishing pad to an operable condition, comprising:

(a) a disk having a circular peripheral edge, a first substantially planar surface to which a first abrasive is attached and a second, opposing substantially planar surface to which a second abrasive is attached, thereby forming two opposing, substantially planar abrasive surfaces, the circular peripheral edge including a first surface that faces toward a second surface;

(b) a base for drivingly linking to a rotatably driven machine, the base having a circular shoulder extending from a base surface, a shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk and receiving the first surface of the peripheral edge of the disk;

(c) a ring having an annular body with a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk and receiving the second surface of the peripheral edge of the disk; and

(d) at least one fastener mounting the ring to the base with the disk held between the ring and the base, wherein the first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface.

25. A holder for a conditioning tool for restoring a used CMP polishing pad to an operable condition, the holder comprising:

(a) a base for drivingly linking to a rotatably driven machine, the base having a circular shoulder extending from a base surface configured to receive a disk having

(i) a circular peripheral edge including a first surface and a second surface;

(ii) a first substantially planar surface to which a first abrasive is attached; and

(iii) a second, opposing substantially planar surface to which a second abrasive is attached, thereby forming two opposing, substantially planar abrasive surfaces, a shoulder diameter being substantially equal to a diameter of the circular peripheral edge of the disk for receiving the first surface of the peripheral edge of the disk;

(b) a ring having an annular body with a circular shoulder defining an aperture having a diameter that is smaller than the diameter of the peripheral edge of the disk, the ring shoulder diameter being substantially equal to the diameter of the peripheral edge of the disk for receiving the second surface of the peripheral edge of the disk; and

(c) at least one fastener for mounting the ring to the base with the disk held between the ring and the base by a clamping force applied to the peripheral edge of the disk by the ring shoulder and the base shoulder, wherein the first abrasive protrudes through the aperture of the ring, and the second abrasive is spaced from the base surface.

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