US20040178065A1 - Electrode semiconductor workpiece holder and processing methods - Google Patents

Abstract

A semiconductor workpiece holder for use in processing a semiconductor workpiece includes a workpiece support operatively mounted to support a workpiece in position for processing. A finger assembly is operatively mounted upon the workpiece support and includes a finger tip. The finger assembly is movable between an engaged position in which the finger tip is engaged against the workpiece, and a disengaged position in which the finger tip is moved away from the workpiece. Preferably, at least one electrode forms part of the finger assembly and includes an electrode contact for contacting a surface of said workpiece. At least one protective sheath covers at least some of the electrode contact. According to one aspect of the invention, a sheathed electrode having a sheathed electrode tip is positioned against a semiconductor workpiece surface in a manner engaging the workpiece surface with said sheathed electrode tip. A seal is formed about the periphery of the electrode tip, and with the electrode tip engaging the workpiece, a desired electrical contact is made to the workpiece. Thereafter, the workpiece is exposed to desired semiconductor processing conditions.

Description

TECHNICAL FIELD
• This invention relates to semiconductor workpiece holders and methods for use in processing semiconductor workpieces.[0001]
BACKGROUND OF THE INVENTION
• Semiconductor workpieces, such as semiconductor wafers and the like, are the subject of extensive processing which most often involves some type of automated or computer controlled processing. In processing semiconductor workpieces it is often desirable to minimize the amount of human contact to which a particular workpiece is exposed. Such reduces the chances of an inadvertent contamination which could render the workpiece useless.[0002]
• Often times during processing, it is necessary to treat a particular workpiece or workplace surface with chemicals, either gaseous or liquid. Such treatment allows for films or layers of material to be deposited or grown on a workpiece surface. One method of accomplishing this is to expose the particular workpiece to desired processing environments in which desired chemicals are present to form or grow such films or layers. Some processing regimes involve moving the workpiece within the processing environment to effectuate film or layer coverage. Other processing regimes involve forming layers on or over a workpiece utilizing various electroplating techniques.[0003]
• The above-described processing scenarios pose, among other challenges, a two-fold challenge. First, a challenge exists to reduce the amount of human contact with a semiconductor workpiece which is undergoing processing. Second, during such processing, challenges exist relating to the treatment of semiconductor workpieces during the various processing stages. For example, in the above described processing context in which a workpiece is exposed to and moved within a processing environment, challenges exist which relate to transferring the workpiece into the environment, effectively holding or maintaining the workpiece within the environment during processing, and moving the workpiece out of the environment at the conclusion of a particular processing stage. With respect to the semiconductor processing steps which utilize electroplating techniques, challenges exist which relate to effectively holding or maintaining the workpiece in a processing environment while a desired electrical bias is imparted to the workpiece.[0004]
• The prior electroplating semiconductor processing equipment has also suffered some difficulty in that providing electrical contact between the electrodes and wafers has frequently led to the buildup of plating material deposits at the point of contact. This deposits can be problematic in subsequent processing steps and lead to defects in the resulting integrated circuits or other devices being made. Thus improved electrode constructions are needed to address this deficiency.[0005]
• This invention grew out of the need to provide improved semiconductor processing devices and methods which effectively and efficiently hold or maintain workpieces within particular processing environments, including processing environments in which electroplating of workpieces takes place.[0006]
BRIEF DESCRIPTION OF THE DRAWINGS
• Preferred embodiments of the invention are described below with reference to the accompanying drawings, which are briefly described below.[0007]
• FIG. 1 is an environmental view of the semiconductor processing head of the present invention showing two processing heads in a processing station, one in a deployed, “closed” or “processing” position, and one in an “open” or “receive wafer” position.[0008]
• FIG. 2 is an isometric view of the semiconductor processing head of the present invention.[0009]
• FIG. 3 is a side elevation view of the processing head of the present invention showing the head in a “receive wafer” position.[0010]
• FIG. 4 is a side elevation view of the processing head of FIG. 3 showing the head in a rotated position ready to lower the wafer into the processing station.[0011]
• FIG. 5 is a side elevation view of the processing head of FIG. 3 showing the head operator pivoted to deploy the processing head and wafer into the bowl of the processing station.[0012]
• FIG. 6 is a schematic front elevation view of the processing head indicating the portions detailed in FIGS. 7 and 8.[0013]
• FIG. 7 is a front elevation sectional view of the left half of the processing head of the apparatus of the present invention also showing a first embodiment of the wafer holding fingers.[0014]
• FIG. 8 is a front elevation sectional view of the left half of the processing head of the apparatus of the present invention also showing a first embodiment of the wafer holding fingers.[0015]
• FIG. 9 is an isometric view of the operator base and operator arm of the apparatus of the present invention with the protective cover removed.[0016]
• FIG. 10 is a right side elevation view of the operator arm of the present invention showing the processing head pivot drive mechanism.[0017]
• FIG. 11 is a left side elevation view of the operator arm of the present invention showing the operator arm drive mechanism.[0018]
• FIG. 12 is schematic plan view of the operator arm indicating the portions detailed in FIGS. 13 and 14.[0019]
• FIG. 13 is a partial sectional plan view of the right side of the operator arm showing the processing head drive mechanism.[0020]
• FIG. 14 is a partial sectional plan view of the left side of the operator arm showing the operator arm drive mechanism.[0021]
• FIG. 15 is a side elevational view of a semiconductor workpiece holder constructed according to a preferred, aspect of the invention.[0022]
• FIG. 16 is a front sectional view of the FIG. 1 semiconductor workpiece holder.[0023]
• FIG. 17 is a top plan view of a rotor which is constructed in accordance with a preferred aspect of this invention, and which is taken along line[0024]3-3 in FIG. 16.
• FIG. 18 is an isolated side sectional view of a finger assembly constructed in accordance with a preferred aspect of the invention and which is configured for mounting upon the FIG. 17 rotor.[0025]
• FIG. 19 is a side elevational view of the finger assembly of FIG. 18.[0026]
• FIG. 20 is a fragmentary cross-sectional enlarged view of a finger assembly and associated rotor structure.[0027]
• FIG. 21 is a view taken along line[0028]7-7 in FIG. 4 and shows a portion of the preferred finger assembly moving between an engaged and disengaged position.
• FIG. 22 is a view of a finger tip of the preferred finger assembly and shows an electrode tip in a retracted or disengaged position (solid lines) and an engaged position (phantom lines) against a semiconductor workpiece.[0029]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” ([0030]Article 1, Section 8).

  TABLE 1
  Listing of Subsections of Detailed Description and
  Pertinent Items with Reference Numerals and Page Numbers

  	Workpiece Support	8
  	semiconductor processing machine 400	8
  	workpiece supports 401	8
  	Workpiece support 402	8
  	Workpiece support 403	8
  	semiconductor manufacturing chamber	8
  	404
  	beam emitter 81	8
  	operator base 405	8
  	processing head 406	8
  	operator arm 407	8
  	wafer holder 408	8
  	fingers 409	8
  	Workpiece holder 408	8
  	workpiece spin axis 410	8
  	process pivot axis 411	8
  	operator pivot axis 412	9
  	workpiece W	9
  	fingertips 414	9
  		9
  	processing bowl 417	9
  	left andright forks 418 and 419	10
  	Operator Base	11
  	operatorbase back portion 420	11
  	operator baseleft yoke arm 421	11
  	operator baseright yoke arm 422	11
  	yoke arm fasteners 423	11
  	operator arm bearings 424	11
  	operator arm 425	11
  	Operator Arm	11
  	process armrear cavity 426	12
  	lift motor 452	12
  	rotate motor 428	12
  	processing headleft pivot shaft 429	12
  	processing headright pivot shaft 430	12
  	Operator Arm-Processing Head Rotate
  	Mechanism	12
  	Processinghead rotate mechanism 431	13
  	rotate shaft 432	13
  	securingcollar 433	13
  	rotate motor support 434	13
  	rotate encoder 435	13
  	rotate pulley inboard bearing 436	14
  	rotate belt 437	14
  	processing head pulley 438	14
  	rotate belt tensioner 439	15
  	tensioner hub 468	15
  	processing head shaft bearing 440	15
  	processing head rotate bearing 469	15
  	processing head shaft bearing 441	15
  	cable brackets 442 and 443	16
  	rotate overtravel protect 444	16
  	rotate flag 447	17
  	Rotateoptical switches 445 and 446	17
  	Operator Arm-Lift Mechanism	17
  	operatorarm lift mechanism 448	17
  	lift motor shaft 454	18
  	lift gear drive 453	18
  	lift drive shaft 456	18
  	lift bushing 449	18
  	anchor plate 458	18
  	anchor fasteners 457	18
  		18
  	Lift bearing 450	18
  	lift bearing support 460	19
  	operator arm frame 461	19
  	lift anchor 451	19
  	liftovertravel protect 462	19
  	lift optical switch low 463	20
  	lift optical switch high 464	20
  	lift flag 465	20
  	lift motor encoder 455	20
  	lift motor 452	20
  	slotted liftflag mounting slots 467	20
  	lift flag fasteners 466	20
  	Processing Head	21
  	processing head housing 470	21
  	circumferential grooves 471	21
  	rotate shaft openings 474 and 475	21
  	left and rightprocessing head mounts	21
  	472
  	processing head door 476	21
  	processing head void 477	22
  	Processing Head Spin Motor	22
  	workpiece holder 478	22
  	spin axis 479	22
  	spin motor 480	23
  	top motor housing 481	23
  	spin motor shaft 483	23
  	workpiece holder rotor 484	23
  		23
  	rotor hub 485	23
  	rotor hub recess 486	23
  	workpiece shaft snap-ring 488	23
  	rotor recess groove 489	23
  	spin encoder 498	24
  	optical tachometer 499	24
  	Processing Head Finger Actuators	26
  	Pneumatic piston 502	27
  	actuator spring 505	27
  	cavity end cap 507	27
  	retaining ring 508	27
  	pneumatic inlet 503	27
  	pneumatic supply line 504	27
  	actuator plate 509	27
  	actuator plate connectscrew 510	27
  	Wave springs 529	27
  	bushing 512	27
  	pneumatic piston recess 511	27
  	finger actuator contacts 513	28
  	Processing Head Workpiece Holder	28
  	finger actuator lever 514	28
  	finger stem 515	29
  	finger diaphragm 519	29
  	workpiece holder rotor 484	29
  	finger opening 521	29
  	rotor diaphragm lip 523	29
  	finger spring 520	29
  	finger actuator tab 522	29
  	finger collar ornut 517	29
  	518	29
  	finger actuator mechanism 500	30
  	cavity 501	30
  	Semiconductor Workpiece Holder -
  	Electroplating Embodiment	30
  	semiconductor workpiece holder 810	30
  	bottom half orbowl 811	31
  	Processing Head and Processing Head
  	Operator	31
  	workpiece support 812	31
  	spin head assembly 814	31
  	lift/rotate assembly 816	31
  	motor 818	32
  	rotor 820	32
  	rotor spin axis 822	32
  	finger assembly 824	33
  	actuator 825	33
  	rotor center piece 826	33
  	spokes 828	33
  	rotor perimeter piece 830	33
  	Finger Assembly	34
  	finger assembly frame 832	35
  	angled slot 832a	35
  	finger assembly frameouter flange 834	35
  	innerdrive plate portion 836	35
  	Finger Assembly Drive System	35
  	bearing 838	36
  	collet 840	36
  	bearingreceptacle 839	36
  	spring 842	36
  	spring seat 844	36
  	Finger Assembly Electrical System	37
  	pin connector 846	37
  	finger 848	37
  	nut 850	37
  	anti-rotation pin 852	37
  	finger tip 854	38
  	electrode contact 858	38
  	Finger Assembly Drive System Interface	38
  	finger actuator 862	38
  	863	39
  	firstmovement path axis 864	39
  	secondary linkage 865	39
  	link arm 867	39
  	actuator torque ring 869	39
  	pneumatic operator 871	39
  	Engaged and Disengaged Positions	40
  	arrow A	41
  	workpiece standoff 865	41
  	bend 866	42
  	Finger Assembly Seal	42
  	868	42
  	rim portion 870	42
  	Methods and Operation	44

• Workpiece Support[0031]
• Turning now to FIG. 1, a[0032]semiconductor processing machine400 having two workpiece supports401 is shown.Workpiece support402 is shown in a “open” or “receive wafer” position in order to receive a workpiece or semiconductor wafer for further processing.Workpiece support403 is shown in a “closed” or “deployed” position wherein the semiconductor wafer has been received by the workpiece support and is being exposed to the semiconductor manufacturing process in thesemiconductor manufacturing chamber404. FIG. 1 also shows anoptional beam emitter81 for emitting a laser beam detected by robotic wafer conveyors to indicate position of the unit.
• Turning now to FIG. 2, an enlarged view of the[0033]workpiece support401 is shown.Workpiece support401 advantageously includesoperator base405, aprocessing head406, and anoperator arm407.Processing head406 preferably includes workpiece holder orwafer holder408 and which further includesfingers409 for securely holding the workpiece during further process and manufacturing steps.Workpiece holder408 more preferably spins aboutworkpiece spin axis410.
• The processing head is advantageously rotatable about processing head pivot axis or, more briefly termed, process[0034]pivot axis411. In this manner, a workpiece (not shown) may be disposed between and grasped by thefingers409, at which point the processing head is preferably rotated about processhead pivot axis411 to place the workpiece in a position to be exposed to the manufacturing process.
• In the preferred embodiment,[0035]operator arm407 may be pivoted aboutoperator pivot axis412. In this manner, the workpiece is advantageously lowered into the process bowl (not shown) to accomplish a step in the manufacture of the semiconductor wafer.
• Turning now to FIGS. 3-5, the sequence of placing a workpiece on the workpiece support and exposing the workpiece to the semiconductor manufacturing process is shown. In FIG. 3, a workpiece W is shown as being held in place by[0036]fingertips414 offingers409. Workpiece W is grasped byfingertips414 after being placed in position by robot or other means.
• Once the workpiece W has been securely engaged by[0037]fingertips414,processing head406 can be rotated about processhead pivot axis411 as shown in FIG. 4.Process head406 is preferably rotated aboutaxis411 until workpiece W is at a desired angle, such as approximately horizontal. Theoperator arm407 is pivoted about operatorarm pivot axis412 in a manner so as to coordinate the angular position ofprocessing head406. In the closed position, the processing head is placed against the rim ofbowl416 and the workpiece W is essentially in a horizontal plane. Once the workpiece W has been secured in this position, any of a series of various semiconductor manufacturing process steps may be applied to the workpiece as it is exposed in theprocessing bowl417.
• Since the[0038]processing head406 is engaged by theoperator arm407 on the left and right side by the preferablyhorizontal axis411 connecting the pivot points ofprocessing head406, a high degree of stability about the horizontal plane is obtained. Further, since theoperator arm407 is likewise connected to theoperator base405 at left and right sides along the essentiallyhorizontal line412 connecting the pivot points of the operator arm, the workpiece support forms a structure having high rigidity in the horizontal plane parallel to and defined byaxes411 and412. Finally, sinceoperator base405 is securely attached to thesemiconductor process machine400, rigidity about thespin axis410 is also achieved.
• Similarly, since processing[0039]head406 is nested within the fork or yoke shapedoperator arm407 having left andright forks418 and419, respectively, as shown in FIG. 2, motion due to cantilevering of the processing head is reduced as a result of the reduced moment arm defined by the line connectingpivot axes411 and412.
• In a typical semiconductor manufacturing process, the[0040]workpiece holder408 will rotate the workpiece, having theprocess head406 secured at two points, that is, at the left andright forks418 and419, respectively, the vibration induced by the rotation of theworkpiece holder408 will be significantly reduced along theaxis411.
• A more complete description of the components of the present invention and their operation and interrelation follows.[0041]
Operator Base
• Turning now to FIG. 9,[0042]operator base405 is shown. The present invention advantageously includes anoperator base405 which forms an essentially yoke-shaped base having an operator base backportion420, an operator base leftyoke arm421, and an operator base right,yoke arm422.Yoke arms421 and422 are securely connected to the base of theyoke420. In the preferred embodiment, the yoke arms are secured to the yoke base by theyoke arm fasteners423. The yoke arm base in turn is advantageously connected to thesemiconductor process machine400 as shown in FIG. 1.
• The upper portions of the yoke arm advantageously include receptacles for housing the[0043]operator arm bearings424 which are used to support the pivot shafts of theoperator arm425, described more fully below.
Operator Arm
• Still viewing. FIG. 9, the present invention advantageously includes an[0044]operator arm407. As described previously,operator arm407 preferably pivots about the operatorarm pivot axis412 which connects the center line defined by the centers of operatorarm pivot bearings424.
• Operator arm or[0045]pivot arm407 is advantageously constructed in such a manner to reduce mass cantilevered about operatorarm pivot axis412. This allows for quicker and more accurate positioning of the pivot arm as it is moved aboutpivot arm axis412.
• The left fork of the[0046]pivot arm418, shown moreclearly in FIG. 11, houses the mechanism for causing the pivot arm to lift or rotate about pivotarm pivot axis412. Pivot armright fork419, shown more clearly in FIG. 10, houses the mechanism for causing the processing head406 (not shown) to rotate about the processhead pivot axis411.
• The process arm[0047]rear cavity426, shown in FIG. 9, houses thelift motor452 for causing theoperator arm407 to rotate aboutpivot arm axis412. Process armrear cavity426 also houses rotatemotor428 which is used to cause theprocessing head406 to rotate about the processinghead pivot axis411. The rotatemotor428 may more generally be described as a processing head pivot or rotate drive.Processing head406 is mounted tooperator arm407 at processing head leftpivot shaft429 and processing headright pivot shaft430.
• [0048]Operator arm407 is securely attached to leftyoke arm421 andright yoke arm422 by operatorarm pivot shafts425 and operatorarm pivot bearings424, the right of which such bearing shaft and bearings are shown in FIG. 9.
Operator Arm-Processing Head Rotate Mechanism
• Turning now to FIG. 13, a sectional plan view of the right rear corner of[0049]operator arm407 is shown. The right rear section ofoperator arm407 advantageously contains the rotate mechanism which is used to rotateprocessing head406 about processinghead pivot shafts430 and429. Processing head rotatemechanism431 preferably consists of rotatemotor428 which drives rotateshaft432, more generally described as a processing head drive shaft. Rotateshaft432 is inserted within rotatepulley425 which also functions as the operator arm pivot shaft. As described previously, the operator arm pivot shaft/lift pulley is supported in operatorarm pivot bearings424, which are themselves supported in operatorbase yoke arm422. Rotateshaft432 is secured within leftpulley424 by securingcollar433. Securingcollar433 secures rotatepulley425 to rotateshaft432 in a secure manner so as to assure a positive connection between rotatemotor428 and rotatepulley425. Aninner cover584 is also provided.
• Rotate[0050]motor428 is disposed within process armrear cavity426 and is supported by rotatemotor support434. Rotatemotor428 preferably is a servo allowing for accurate control of speed and acceleration of the motor.Servo motor428 is advantageously connected to rotateencoder435 which is positioned on one end of rotatemotor428. Rotateencoder435, more generally described as a processing head encoder, allows for accurate measurement of the number of rotations of rotatemotor428, as well as the position, speed, and acceleration of the rotateshaft432. The information from the rotate encoder may be used in a rotate circuit which may then be used to control the rotate motor when the rotate motor is a servo. This information is useful in obtaining the position and rate of travel of the processing head, as well as controlling the final end point positions of the processing head as it is rotated about process head rotateaxis411.
• The relationship between the rotate motor rotations, as measured by rotate[0051]encoder435, may easily be determined once the diameters of the rotatepulley425 and theprocessing head pulley438 are known. These diameters can be used to determine the ratio of rotate motor relations to processing head rotations. This may be accomplished by a microprocessor, as well as other means.
• Rotate[0052]pulley425 is further supported withinoperator arm407 by rotate pulley inboard bearing436 which is disposed about an extended flange on the rotatepulley425. Rotate pulley inboard bearing436 is secured by the body of theoperator arm407, as shown in FIG. 13.
• Rotate[0053]pulley425 advantageously drives rotatebelt437, more generally described as a flexible power transmission coupling. Referring now to FIG. 10, rotatebelt437 is shown in the side view of theright arm419 of theoperator arm407. Rotatebelt437 is preferably a toothed timing belt to ensure positive engagement with the processing head drive wheel, more particularly described herein as theprocessing head pulley438, (not shown in this view). In order to accommodate thetoothed timing belt437, both the rotatepulley425 and theprocessing head pulley438 are advantageously provided with gear teeth to match the tooth pattern of the timing belt to assure positive engagement of the pulleys with the rotate belt.
• Rotate[0054]mechanism431 is preferably provided with rotatebelt tensioner439, useful for adjusting the belt to take up slack as the belt may stretch during use, and to allow for adjustment of the belt to assure positive engagement with both the rotate pulley and the processing head pulley. Rotatebelt tensioner439 adjusts the tension of rotatebelt437 by increasing the length of the belt path between rotatepulley425 andprocessing head pulley438, thereby accommodating any excess length in the belt. Inversely, the length of the belt path may also be shortened by adjusting rotatebelt tensioner439 so as to create a more linear path in the upper portion of rotatebelt437. Thetensioner439 is adjusted by rotating it abouttensioner hub468 and securing it in a new position.
• Turning now to FIG. 13,[0055]processing head pulley438 is mounted to processing head rotateshaft430 in a secured manner so that rotation ofprocessing head pulley438 will cause processing head rotateshaft430 to rotate.Processing head shaft430 is mounted to operator armright fork419 by processing head shaft bearing440, which in turn is secured in the frame of theright fork419 by processing head rotate bearing469. In a like manner,processing head shaft429 is mounted in operator armleft fork418 by processing head shaft bearing441, as shown in FIG. 9.
• Processing[0056]head pivot shafts430 and429 are advantageously hollow shafts. This feature is useful in allowing electrical optical, pneumatic, and other signal and supply services to be provided to the processing head. Service lines such as those just described which are routed through the hollow portions of processinghead pivot shafts429 and430 are held in place in the operator arms bycable brackets442 and443.Cable brackets442 and443 serve a dual purpose. First, routing the service lines away from operating components within the operator arm left and right forks. Second,cable brackets442 and443 serve a useful function in isolating forces imparted to the service cables by the rotating action ofprocessing head406 as it rotates about processinghead pivot shafts429 and430. This rotating of theprocessing head406 has the consequence that the service cables are twisted within the pivot shafts as a result of the rotation, thereby imparting forces to the cables. These forces are preferably isolated to a particular area so as to minimize the effects of the forces on the cables. Thecable brackets442 and443 achieve this isolating effect.
• The process head rotate[0057]mechanism431, shown in FIG. 13, is also advantageously provided with a rotate overtravel protect444,which functions as a rotate switch. Rotate overtravel protect444 preferably acts as a secondary system to the rotateencoder435 should the control system fail for some reason to stopservo428 in accordance with a predetermined position, as would be established by rotateencoder435. Turning to FIG. 13, the rotate overtravel protect444 is shown in plan view. The rotate overtravel protect preferably consists of rotateoptical switches445 and446, which are configured to correspond to the extreme (beginning and end point) portions of the processing head, as well as the primary switch component which preferably is a rotateflag447. Rotateflag447 is securely attached to processinghead pulley438 such that when processing head shaft430 (and consequently processing head406) are rotated by virtue of drive forces imparted to the processing head pulled425 by the rotatebelt437, the rotateflag447 will rotate thereby tracking the rotate motion ofprocessing head406. Rotateoptical switches445 and446 are positioned such that rotateflag447 may pass within the optical path generated by each optical switch, thereby generating a switch signal. The switch signal is used to control an event such as stopping rotatemotor428. Rotateoptical switch445 will guard against overtravel ofprocessing head406 in one direction, while rotateoptical switch446 will provide against overtravel of theprocessing head406 in the opposite direction.
Operator Arm-Lift Mechanism
• [0058]Operator arm407 is also advantageously provided with an operatorarm lift mechanism448 which is useful for causing the operator arm to lift, that is, to pivot or rotate about operatorarm pivot axis412. Turning to FIG. 14, the operatorarm lift mechanism448 is shown in the sectional plan view of the right rear corner ofoperator arm407.
• Operator[0059]arm lift mechanism448 is advantageously driven bylift motor452.Lift motor452 may be more generally described as an operator arm drive or operator arm pivot drive.Lift motor452 is preferably a servo motor and is more preferably provided with an operator encoder, more specifically described aslift motor encoder456. Whenlift motor452 is a servo motor coupled withlift encoder456, information regarding the speed and absolute rotational position of thelift motor shaft454 may be known from the lift encoder signal. Additionally, by virtue of being a servo mechanism, the angular speed and acceleration oflift motor452 may be easily controlled by use of the lift signal by an electrical circuit. Such a lift circuit may be configured to generate desired lift characteristics (speed, angle, acceleration, etc.). FIG. 14 shows that the lift operator may also include abrake455 which is used to safely stop the arm if power fails.
• [0060]Lift motor452 drives liftmotor shaft454 which in turn drives liftgear drive453. Lift gear drive453 is a gear reduction drive to produce a reduced number of revolutions atlift drive shaft456 as the function of input revolutions fromlift motor shaft454.
• Lift[0061]drive gear shaft456 is secured to liftanchor451 which is more clearly shown in FIG. 11.Lift anchor451 is preferably shaped to have at least one flat side for positively engaginglift bushing449.Lift anchor451 is secured to liftdrive shaft456 byanchor plate458 andanchor fasteners457. In this manner, whenlift drive shaft456 is rotated, it will positively engagelift bushing449. Returning to FIG. 14, it is seen thatlift bushing449 is mounted in operator leftyoke arm421, and is thus fixed with respect tooperator base405. Lift bearing450 is disposed about the lift bushing shank and is supported inoperator arm407 bylift bearing support460 which is a bushing configured to receive lift bearing450 on a first end and to support lift gear drive453 on a second end. Lift bearingsupport460 is further supported withinoperator arm407 byoperator arm frame461. The lift arm is thus free to pivot aboutlift bushing449 by virtue oflift bearing450.
• In operation, as[0062]lift motor452 causes lift gear drive453 to produce rotations atgear drive shaft456,lift anchor451 is forced againstlift bushing449 which is securely positioned within rightoperator yoke arm421. The reactive force against thelift anchor451 will causelift bearing support460 to rotate relative to liftbushing449. Sincelift bushing449 is fixed inoperator base405, and sinceoperator base405 is fixed to processingmachine400, rotation oflift bearing support460 will causelift arm407 to pivot about operatorarm pivot axis412, thereby moving theprocessing head406. It is advantageous to consider the gear drive shaft (or “operator arm shaft”) as being fixed with respect tooperator base405 when envisioning the operation of the lift mechanism.
• [0063]Operator lift mechanism448 is also advantageously provided with a lift overtravel protect462 or lift switch. The, lift rotate protect operates in a manner similar to that described for the rotate overtravel protect444 described above. Turning now to FIG. 11, a left side view of theoperator arm407 is shown which shows the lift overtravel protect in detail.
• The lift overtravel protect preferably includes a lift optical switch low[0064]463 and a lift optical switch high464. Other types of limit switches can also be used. The switch high464 and switch low463 correspond to beginning and endpoint travel oflift arm407. The primary lift switch component islift flag465, which is firmly attached to left operatorbase yoke arm421. The lift optical switches are preferably mounted to themovable operator arm407. Asoperator arm407 travels in an upward direction in pivoting about operatorarm pivot axis412, lift optical switch high464 will approach thelift flag465. Should thelift motor encoder455 fail to stop thelift motor454, as desired, thelift flag465 will break the optical path of the lift optical switch high464 thus producing a signal which can be used to stop the lift motor. In like manner, when theoperator arm407 is being lowered by rotating it in a clockwise direction about the operatorarm pivot axis412, as shown in FIG. 11, overtravel ofoperator arm407 will cause lift optical switch low463 to have its optical path interrupted bylift flag465, thus producing a signal which may be used to stoplift motor452. As is shown in FIG. 11,lift flag465 is mounted to left operatorbase yoke arm421 with slotted liftflag mounting slots467 and removablelift flag fasteners466. Such an arrangement allows for the lift flag to be adjusted so that the lift overtravel protect system only becomes active after thelift arm407 has traveled beyond a preferred point.
Processing Head
• Turning now to FIG. 6, a front elevation schematic view of the[0065]processing head406 is shown.Processing head406 is described in more detail in FIGS. 7 and 8. Turning now to FIG. 7, a sectional view of the left front side ofprocessing head406 is shown.Processing head406 advantageously includes a processing head housing470 andframe582.Processing head406 is preferably round in shape in plan view allowing it to easily pivot about processhead pivot axis411 with no interference fromoperator arm407, as demonstrated in FIGS. 3-5. Returning to FIG. 7, processing head housing470 more preferably hascircumferential grooves471 which are formed into the side of process head housing470.Circumferential grooves471 have a functional benefit of increasing heat dissipation from processinghead406.
• The sides of processing head housing[0066]470 are advantageously provided with rotateshaft openings474 and475 for receiving respectively left and right processinghead pivot shafts429 and430. Processinghead pivot shafts429 and430 are secured to theprocessing head406 by respective left and right processing head mounts472 and473. Processing head mounts472 and473 are affirmative connected toprocessing head frame582 which also supports processinghead door476 which is itself securely fastened to processing head housing470. Consequently, processinghead pivot shafts429 and430 are fixed with respect toprocessing head407 and may therefore rotate or pivot with respect tooperator arm407. The details of how processinghead pivot shafts429 and430 are received withinoperator arm407 were discussed supra.
• Processing head housing[0067]470 forms aprocessing head void477 which is used to house additional processing head components such as s the spin motor, the pneumatic finger actuators, and service lines, all discussed more fully below.
• The processing head also advantageously includes a workpiece holder and fingers for holding a workpiece, as is also more fully described below.[0068]
Processing Head Spin Motor
• In a large number of semiconductor manufacturing processes, is desirable to spin the semiconductor wafer or workpiece during the process, for example to assure even distribution of applied process fluids across the face of the semiconductor wafer, or to aid drying of the wafer after a wet chemistry process. It is therefore desirable to be able to rotate the semiconductor workpiece while it is held by the processing head.[0069]
• The semiconductor workpiece is held during the process by[0070]workpiece holder478 described more fully below. In order to spinworkpiece holder478 relative toprocessing head406 aboutspin axis479, an electric, pneumatic, or other type of spin motor or workpiece spin drive is advantageously provided.
• Turning to FIG. 8,[0071]spin motor480 hasarmatures526 which drivespin motor shaft483 in rotational movement to spinworkpiece holder478.Spin motor480 is supported by bottom motor bearing492 inbottom motor housing482.Bottom motor housing482 is secured toprocessing head406 bydoor476.Spin motor480 is thus free to rotate relative to processing head housing470 anddoor476.Spin motor480 is preferably additionally held in place bytop motor housing481 which rests on processinghead door476.Spin motor480 is rotationally isolated fromtop motor housing481 by top motor bearing493, which is disposed between thespin motor shaft483 andtop motor housing481.
• The spin motor is preferably an electric motor which is provided with an electrical supply source through[0072]pivot shaft429 and/or430.Spin motor480 will drivespin motor shaft483 aboutspin axis479.
• To secure[0073]workpiece holder rotor484 to spinmotor shaft483, workpiece holder,rotor484 is preferably provided with arotor hub485.Rotor hub485 defines arotor hub recess486 which receives a flared end ofworkpiece holder shaft491. The flaredend487 ofworkpiece holder shaft491 is secured within therotor hub recess486 by workpiece shaft snap-rings488 which fits withinrotor recess groove489 above the flaredportion487 ofworkpiece holder shaft491.
• The[0074]workpiece holder shaft491 is fitted inside ofspin motor shaft483 and protrudes from the top of the spin motor shaft. The top ofworkpiece holder shaft491 is threaded to receive thin nut527 (see FIG. 7).Thin nut527 is tightened against optical tachometer499 (describe more fully below).Optical tachometer499 is securely attached to spinmotor shaft483 such that as thespin motor480 rotationally drives thespin motor shaft483, theworkpiece holder shaft491 is also driven.
• Workpiece holders may be easily changed out to accommodate various configurations which may be required for the various processes encountered in manufacturing of the semiconductors. This is accomplished by removing spin encoder[0075]498 (described below), and thenthin nut527. Once the thin nut has been removed theworkpiece holder478 will drop away from theprocessing head406.
• The processing head is also advantageously provided with a[0076]spin encoder498, more generally described as a workpiece holder encoder, and anoptical tachometer499. As shown in FIG. 7,spin encoder498 is mounted totop motor housing481 byencoder support528 so, as to remain stationary with respect to theprocessing head406.Optical tachometer499 is mounted onspin motor shaft483 so as to rotate with themotor480. When operated in conjunction, the siringencoder498 andoptical tachometer499 allow the speed, acceleration, and precise rotational position of the spin motor shaft (and therefore the workpiece holder478) to be known. In this manner, and whenspin motor480 is provided as a servo motor, a high degree of control over the spin rate, acceleration, and rotational angular position of the workpiece with respect to theprocess head407 may be obtained.
• In one application of the present invention the workpiece support is used to support a semiconductor workpiece in an electroplating process. To accomplish the electroplating an electric current is provided to the workpiece through an alternate embodiment of the fingers (described more fully below). To provide electric current to the finger, conductive wires are run from the tops of the fingers inside of the[0077]workpiece holder478 through the electrode wire holes525 in the flared a lower part ofworkpiece holder shaft491. The electrode wires are provided electric current from electrical lines run through processingpivot shaft429 and/or430.
• The electrical line run through[0078]pivot shaft430/429 will by nature be stationary with respect to processing head housing470. However, since the workpiece holder rotor is intended to be capable of rotation during the electroplating process, the wires passing intoworkpiece support shaft491 through electrode wire holes525 may rotate with respect to processing head housing470. Since the rotating electrode wires withinworkpiece shaft491 and the stationary electrical supply lines run throughpivot shaft430/429 must be in electrical communication, the rotational/stationary problem must be overcome. In the preferred embodiment, this is accomplished by use ofelectrical slip ring494.
• [0079]Electrical slip ring494, shown in FIG. 7, has alower wire junction529 for receiving the conductive ends of the electrical wires passing intoworkpiece holder shaft491 by electrode wire holes525.Lower wire junction529 is held in place withinworkpiece holder shaft491 by insulatingcylindrical collar497 and thus rotates withspin motor shaft483. The electrode wires terminate in a singleelectrical contact531 at the top of thelower wire junction529.Electrical slip ring494 further has acontact pad530 which is suspended within the top ofworkpiece holder shaft491.Contact pad530 is mechanically fastened to spinencoder498, which, as described previously, remains stationary with respect to processing head housing470. The stationary-to-rotational transition is made at the tip ofcontact pad530, which is in contact with the rotatingelectrical contact531.Contact pad530 is electrically conductive and is in electrical communication withelectrical contact531. In the preferred embodiment,contact pad530 is made of copper-beryllium. Awire585 carries current to finger assemblies when current supply is needed, such as on the alternative embodiment described below.
Processing Head Finger Actuators
• [0080]Workpiece holder478, described more fully below, advantageously includes fingers for holding the workpiece W in the workpiece holder, as shown in FIGS. 7 and 8. Since theworkpiece holder478 may be removed as described above, it is possible to replace one style of workpiece holder with another. Since a variety of workpiece holders with a variety of fingers for holding the workpiece is possible, it is desirable to have a finger actuator mechanism disposed withinprocessing head407 which is compatible with any given finger arrangement. The invention is therefore advantageously provided with a finger actuator mechanism.
• Turning to FIG. 7, a[0081]finger actuator mechanism500 is shown.Finger actuator mechanism500 is preferably a pneumatically operated mechanism. A pneumatic cylinder is formed by acavity501 withintop motor housing481.Pneumatic piston502 is disposed withincavity501.Pneumatic piston502 is biased in an upward position withincavity501 byactuator spring505.Actuator spring505 is confined withincavity501 bycavity end cap507, which is itself constrained by retainingring508. Pneumatic fluid is provided to the top ofpneumatic piston502 viapneumatic inlet503. Pneumatic fluid is provided topneumatic inlet503 bypneumatic supply line504 which is routed through processinghead pivot shaft429 and hence through theleft fork418 of theoperator arm407. Turning to FIG. 8, it can be seen that a second pneumatic cylinder which is identical to the pneumatic cylinder just described is also provided.
• [0082]Pneumatic piston502 is attached toactuator plate509 by actuator plate connectscrew510. Wave springs529 provide flexibility to the connecting atscrews510.Actuator plate509 is preferably an annular plate concentric with the spin motor580 and disposed about thebottom motor housing482, and is symmetrical aboutspin axis479.Actuator plate509 is secured againstpneumatic piston502 by bushing512 which is disposed inpneumatic piston recess511 aboutpneumatic piston502. Bushing512 acts as a support for wave springs529 to allow a slight tilting of theactuator plate509. Such an arrangement is beneficial for providing equal action against thefinger actuator contracts513 about the entire actuator plate orring509.
• When pneumatic fluid is provided to the space above the[0083]pneumatic piston502, thepneumatic piston502 travels in a downward direction compressingactuator spring505. Aspneumatic piston502 travels downward,actuator plate509 is likewise pushed downward byflexible bushing512.Actuator plate509 will contactfinger actuator contacts513 causing the fingers to operate as more fully described below.
• Actuator seals[0084]506 are provided to prevent pneumatic gas from bypassing the top of thepneumatic piston502 and entering the area occupied byactuator spring505.
Processing Head Workpiece Holder
• [0085]Workpiece holder478 is used to hold the workpiece W, which is typically a semiconductor wafer, in position during the semiconductor manufacturing process.
• Turning now to FIG. 8, a[0086]finger409 is shown in cross section.Finger409 advantageously includes afinger actuator contact513 which is contacted byactuator plate509, as described above.Finger actuator contact513 is connected to finger actuator lever514 (more generally, “finger extensions”) which is cantilevered from and connected to thefinger stem515.Finger stem515 is inserted intofinger actuator lever514. Disposed about the portion of the finger actuator lever which encompasses and securesfinger stem515 isfinger diaphragm519.Finger diaphragm519 is preferably made of a flexible material such as Tetrafluoroethylene, also known as Teflon® (registered trademark of E. I. DuPont de Nemours Company).Finger409 is mounted toworkpiece holder rotor484 usingfinger diaphragm519.Finger diaphragm519 is inserted into thefinger opening521 inrotor484. Thefinger diaphragm519 is inserted into the rotor from the side opposite that to which the workpiece will be presented.Finger diaphragm519 is secured torotor484 againstrotor diaphragm lip523. Forces are intentionally imparted as a result of contact between theactuator plate509 and thefinger actuator contact513 when thefinger actuator mechanism500 is actuated.
• [0087]Finger actuator lever514 is advantageously biased in a horizontal position byfinger spring520 which acts onfinger actuator tab522 which in turn is connected to fingeractuator lever514.Finger spring520 is preferably a torsion spring secured to theworkpiece holder rotor484.
• [0088]Finger stem515 is also preferably provided with finger collar ornut517 which holds thefinger stem515 againstshoulder518.Finger collar517 threads or otherwise securely fits over the lower end offinger actuator lever514. Below thefinger collar517, finger stem515 extends for a short distance and terminates infingertip414.Fingertip414 contains a slight groove or notch which is beneficially shaped to receive the edge of the workpiece W.
• In actuation,[0089]finger actuator plate509 is pushed downward byfinger actuator mechanism500.Finger actuator plate509 continues its downward travel contactingfinger actuator contacts513. Asactuator plate509 continues its downward travel, finger actuator contacts are pushed in a downward direction. As a result of the downward direction, the finger actuator levers514 are caused to pivot.
• In the preferred embodiment, a plurality of fingers are used to hold the workpiece. In one example, six fingers were used. Once the[0090]actuator plate509 has traveled its full extent, the finger stems515 will be tilted away from thespin axis479. The circumference described by the fingertips in this spread-apart position should be greater than the circumference of the workpiece W. Once a workpiece W has been is positioned proximate to the fingertips, the pneumatic pressure is relieved on the finger actuator and theactuator spring505 causes thepneumatic piston502 to return to the top of thecavity501. In so doing, theactuator plate509 is retracted and the finger actuator levers are returned to their initial position by virtue of finger springs520.
Semiconductor Workpiece Holder—Electroplating Embodiment
• FIG. 15 is a side elevational view of a[0091]semiconductor workpiece holder810 constructed according to a preferred aspect of the invention.
• [0092]Workpiece holder810 is used for processing a semiconductor workpiece such as a semiconductor wafer shown in phantom at W. One preferred type of processing undertaken withworkpiece holder810 is a workpiece electroplating process in which a semiconductor workpiece is held byworkpiece holder810 and an electrical potential is applied to the workpiece to enable plating material to be plated thereon. Such can be, and preferably is accomplished utilizing a processing enclosure or chamber which includes a bottom half orbowl811 shown in phantom lines in FIG. 1.Bottom half811 together withworkpiece holder810 forms a sealed, protected chamber for semiconductor workpiece processing. Accordingly, preferred reactants can be introduced into the chamber for further processing. Another preferred aspect ofworkpiece holder810 is that such moves, rotates or otherwise spins the held workpiece during processing as will be described in more detail below.
Processing Head and Processing Head Operator
• Turning now to FIG. 15,[0093]semiconductor workpiece holder810 includes aworkpiece support812.Workpiece support812 advantageously supports a workpiece during processing.Workpiece support812 includes a processing head or spinhead assembly814.Workpiece support812 also includes a head operator or lift/rotateassembly816.Spin head assembly814 is operatively coupled with lift/rotateassembly816.Spin head assembly814 advantageously enables a held workpiece to be spun or moved about a defined axis during processing. Such enhances conformal coverage of the preferred plating material over the held workpiece. Lift/rotateassembly816 advantageously lifts spinhead assembly814 out of engagement with thebottom half811 of the enclosure in which the preferred processing takes place. Such lifting is preferably about an axis x₁. Once so lifted, lift/rotateassembly816 also rotates the spin head and held workpiece about an axis x₂so that the workpiece can be presented face-up and easily removed fromworkpiece support812. In the illustrated and preferred embodiment, such rotation is about 180° from the disposition shown in FIG. 15. Advantageously, a new workpiece can be fixed or otherwise attached to the workpiece holder for further processing as described in detail below.
• The workpiece can be removed from or fixed to[0094]workpiece holder810 automatically by means of a robotically controlled arm. Alternatively, the workpiece can be manually removed from or fixed toworkpiece holder810. Additionally, more than one workpiece holder can be provided to support processing of multiple semiconductor workpieces. Other means of removing and fixing a semiconductor workpiece are possible.
• FIG. 16 is a front sectional view of the FIG. 15 semiconductor workpiece holder. As shown,[0095]workpiece support812 includes amotor818 which is operatively coupled with arotor820.Rotor820 is advantageously mounted for rotation about arotor spin axis822 and serves as a staging platform upon which at least onefinger assembly824 is mounted. Preferably, more than one finger assembly is mounted onrotor820, and even more preferably, four or more such finger assemblies are mounted thereon and described in detail below although only two are shown in FIG. 16. The preferred finger assemblies are instrumental in fixing or otherwise holding a semiconductor workpiece onsemiconductor workpiece holder810. Each finger assembly is advantageously operatively connected or associated with aactuator825. The actuator is preferably a pneumatic linkage which serves to assist in moving the finger assemblies between a disengaged position in which a workpiece may be removed from or added to the workpiece holding, and an engaged position in which the workpiece is fixed upon the workpiece holder for processing. Such is described in more detail below.
• FIG. 17 is a top or plan view of[0096]rotor820 which is effectively taken along line3-3 in FIG. 16. FIG. 16 shows the preferred .fourfinger assemblies824. As shown,rotor820 is generally circular and resembles from the top a spoked wheel with a nearly continuous bottom surface.Rotor820 includes arotor center piece826 at the center of which liesrotor axis822. A plurality of struts orspokes828 are joined or connected torotor center826 and extend outwardly to join with and support arotor perimeter piece830. Advantageously, four ofspokes828 support respectivepreferred finger assemblies824.Finger assemblies824 are advantageously positioned to engage a semiconductor workpiece, such as a wafer W which is shown in phantom lines in the position such would occupy during processing. When a workpiece is so engaged, it is fixedly held in place relative to the rotor so that processing can be effected. Such processing can include exposing the workpiece to processing conditions which are effective to form a layer of material on one or more surfaces or potions of a wafer or other workpiece. Such processing can also include moving the workpiece within a processing-environment to enhance or improve conformal coverage of a layering material. Such processing can, and preferably does include exposing the workpiece to processing conditions which are effective to form an electroplated layer on or over the workpiece.
Finger Assembly
• Referring now to FIGS. 18-20, various views of a preferred finger assembly are shown. The preferred individual finger assemblies are constructed in accordance with the description below. FIG. 18 is an isolated side sectional view of a finger assembly constructed in accordance with a preferred aspect of the invention. FIG. 19 is a side elevational view of the finger assembly turned 90° from the, view of FIG. 18. FIG. 20 is a fragmentary cross-sectional enlarged view of a finger assembly and associated rotor structure. The finger assembly as set forth in FIGS. 18 and 19 is shown in the relative position such as it would occupy when processing head or spin head assembly[0097]814 (FIGS. 15 and 16) is moved or rotated by head operator or lift/rotateassembly816 into a position for receiving a semiconductor workpiece. The finger assembly is shown in FIGS. 18 and 20 in an orientation of about 180° from the position shown in FIG. 20. This typically varies becausespin head assembly814 is rotated 180° from the position shown in FIGS. 15 and 16 in order to receive a semiconductor workpiece. Accordingly,finger assemblies824 would be so rotated. Lesser degrees of rotation are possible.
• [0098]Finger assembly824 includes afinger assembly frame832. Preferably,finger assembly frame832 is provided in the form of a sealed contact sleeve which includes an angled slot832a, only a portion of which is shown in FIG. 19. Angled slot832aadvantageously enables the finger assembly to be moved, preferably pneumatically, both longitudinally and rotationally as will be explained below. Such preferred movement enables a semiconductor workpiece to be engaged, electrically contacted, and processed in accordance with the invention.
• [0099]Finger assembly frame832 includes a finger assembly frameouter flange834 which, as shown in FIG. 20, engages an innerdrive plate portion836 ofrotor820. Such engagement advantageously fixes or seatsfinger assembly frame832 relative torotor820. Such, in turn, enables the finger assembly, or a portion thereof, to be moved relative to the rotor for engaging the semiconductor workpiece.
Finger Assembly Drive System
• Referring to FIGS. 16 and 18-[0100]20, the finger assembly includes a finger assembly drive system which is utilized to move the finger assembly between engaged and disengaged positions. The finger assembly drive system includes abearing838 and acollet840 operatively adjacent the bearing. Bearing838 includes a bearingreceptacle839 for receiving a pneumatically driven source, a fragmented portion of which is shown directly above the receptacle in FIG. 20. The pneumatically driven source serves to longitudinally reciprocate and rotatecollet840, and hence a preferred portion offinger assembly824. A preferred pneumatically driven source is described below in more detail in connection with the preferred longitudinal and rotational movement effectuated thereby. Such longitudinal reciprocation is affected by a biasing mechanism in the form of aspring842 which is operatively mounted betweenfinger assembly frame832 and aspring seat844. The construction develop a bias betweenfinger assembly frame832 andspring seat844 to bias the finger into engagement against a wafer. Advantageously, the cooperation between the above mentioned pneumatically driven source as affected by the biasing mechanism of the finger assembly drive system, enablecollet840 to be longitudinally reciprocated in both extending and retracting modes of movement. As such,finger assembly824 includes a biased portion which is biased toward a first position and which is movable to a second position away from the first position. Other manners of longitudinally reciprocating the finger assembly are possible.
Finger Assembly Electrical System
• Referring to FIGS. 16 and 19, the finger assembly preferably includes a finger assembly electrical system which is utilized to effectuate an electrical bias to a held workpiece and supply electrical current relative thereto. The finger assembly electrical system includes a[0101]pin connector846 and afinger848. Pin connector84 advantageously provides an electrical connection to a power source (not shown) viawire585 and associate slip ring mechanism, described above in connection with FIG. 7 and other FIGS. This is for delivering an
• electrical bias and current to an electrode which is described below.[0102]Pin connector846 also rides within angled slot832athereby mechanically defining the limits to which the finger assembly may be both longitudinally and rotationally moved.
• [0103]Finger848 is advantageously fixed or secured to or withincollet840 by anut850 which threadably engages a distal end portion ofcollet840 as shown best in FIG. 18. Ananti-rotation pin852 advantageously securesfinger848 withincollet840 and prevents relative rotation therebetween. Electrical current is conducted fromconnector846 throughcollet840 tofinger860, all of which are conductive, such as from stainless steel. The finger and collet can be coated with a suitabledielectric coating856, such as TEFLON or others. Thecollet840 andfinger member860 are in one form of the invention made hollow and tubular to conduct a purge gas therethrough.
• [0104]Finger assembly824 may also optionally include a distal tip orfinger tip854.Tip854 may also have a purge gas passage formed therethrough.Finger tip854 advantageously engages against a semiconductor workpiece (see FIG. 20) and assists in holding or fixing the position of the workpiece relative toworkpiece holder810.Finger tip854 also assists in providing an operative electrical connection between the finger assembly and a workpiece to which an electrical biased is to be applied and through which current can move. Finger tip85 can include anelectrode contact858 for electrically contacting a surface of a semiconductor workpiece once such workpiece is secured as describe below.
Finger Assembly Drive System Interface
• A finger assembly drive system interface is operatively coupled with the finger assembly drive system to effectuate movement of the finger assembly between the engaged and disengaged positions. A preferred finger assembly drive system interface is described with reference to FIGS. 16 and 20. One component of the finger assembly drive system interface is a[0105]finger actuator862.Finger actuator862 is advantageously provided for moving the finger assembly between the engaged and disengaged position.Finger actuator862 acts by engagingbearing receptacle839 and movingfinger assembly824 between an engaged position and a disengaged position. In the engaged position,finger tip854 is engaged against a semiconductor workpiece. In the disengagedposition finger tip854 is moved away from the workpiece.
• The finger assembly drive system interface includes pneumatic actuator[0106]825 (FIG. 16).Pneumatic actuators825 are operatively connected to anactuation ring863 and operates thereupon causing the drive plate to move reciprocally in the vertical direction as viewed in FIG. 16.Finger actuator862 is operatively connected toactuation ring863 in a manner which, upon pneumatic actuation, moves the finger actuator into engagement with bearingreceptacle839 along the dashed line in FIG. 20. Such allows or enables the finger assembly to be moved longitudinally along a firstmovement path axis864.
• [0107]Pneumatic actuator linkage825 also includes asecondary linkage865.Secondary linkage865 is pneumatic as well and includes alink arm867.Link arm867 is connected or joined to anactuator torque ring869. Preferably,torque ring869 is concentric with rotor820 (FIG. 17) and circuitously links each of the finger actuators together. Apneumatic operator811 is advantageously linked with thesecondary linkage865 for applying force and operating the linkage by angularly displacingtorque ring869. This in turn rotates the finger assemblies into and away from the engaged position.
• Preferably finger[0108]actuator engagement bits862, under the influence ofpneumatic linkage825, moves the finger assembly, and more specifically collet840 andfinger848 along a first axial movement path alongaxis864. The fingeractuator engagement bits862, then under the influence ofpneumatic operator871 are turned about the axes of each bit like a screwdriver. This movescollet840 andfinger848 in a second angular movement. Such second movement turns the fingers sufficiently to produce the angular displacement shown in FIG. 21. According to a preferred aspect of this invention, such movement of the finger assemblies between the engaged and disengaged positions takes place whenspin head assembly814 has been moved 180° from its FIG. 21 disposition into a face-up condition.
• The[0109]engagement bits862 can be provided with a purge gas passage therethrough. Gas is supplied viatube893 and is passed through the finger assemblies.
Engaged and Disengaged Positions
• FIG. 21 is a view of a portion of a finger assembly, taken along line[0110]7-7 in FIG. 18. Such shows in more detail the above-described engaged and disengaged positions and movement therebetween relative to a workpiece W. In the disengaged position,finger848 is positioned adjacent the semiconductor workpiece and the finger tip and electrode contact do not overlap with workpiece W. In the engaged position, the finger tip overlaps with the workpiece and the electrode is brought to bear against the workpiece. From the disengaged position,finger assembly824, upon the preferred actuation, is moved in a first direction away from, the disengaged position. Preferably, such first direction is longitudinal and along firstmovement path axis864. Such longitudinal movement is linear and in the direction of arrow A as shown in FIGS. 18 and 19. The movement moves the finger assembly to the position shown in dashed lines in FIG. 18. Such movement is effectuated bypneumatic operator825 which operates upon actuation ring863 (FIG. 16). This in turn, causesfinger actuator862 to engage withfinger assembly824. Such linear movement is limited by angled slot832a. Thereafter, the finger assembly is preferably moved in a second a direction which is different from the first direction and preferably rotational about the firstmovement path axis864. Such is illustrated in FIG. 21 where the second direction defines a generally actuate path between the engaged and disengaged positions. Such rotational movement is effectuated bysecondary linkage865 which pneumatically engages the finger actuator to effect rotation thereof. As so moved, the finger assembly swings into a ready position in which a semiconductor workpiece is ready to be engaged and held for processing. Once the finger assembly is moved or swung into place overlapping a workpiece, the preferred finger actuator is spring biased and released to bear against the workpiece. An engaged workpiece is shown in FIG. 20 after the workpiece has been engaged byfinger tip854 against aworkpiece standoff865, and spinhead assembly814 has been rotated back into the position shown in FIG. 15. Such preferred pneumatically assisted engagement takes place preferably alongmovement path axis864 and in a direction which is into, the plane of the page upon which FIG. 21 appears.
• As shown in FIG. 18,[0111]finger848 extends away fromcollet840 and preferably includes abend866 betweencollet840 andfinger tip854. The preferred bend is a reverse bend of around 180° which serves to pointfinger tip854 toward workpiece W when the finger assembly is moved toward or into the engaged position (FIG. 21). Advantageously, thecollet840 and hence finger848 are longitudinally reciprocally movable into and out of the engaged position.
Finger Assembly Seal
• The finger assembly preferably includes a[0112]finger assembly seal868 which is effectuated betweenfinger848 and a desired workpiece when the finger assembly is moved into the engaged position. Preferably,adjacent finger tip854.Seal868 is mountedadjacent electrode contact858 and effectively seals the electrode contact therewithin whenfinger assembly824 is moved to engage a workpiece. The seal can be made of a suitable flexible, preferably elastomeric material, such as VITON.
• More specifically, and referring to FIG. 22,[0113]seal868 can include arim portion870 which engages workpiece surface W and forms a sealing contact therebetween when the finger assembly is moved to the engaged position. Such seal advantageously isolatesfinger electrode860 from the processing environment and materials which may plate out or otherwise be encountered therein.Seal868 can be provided with an optional bellows wall structure894 (FIG. 22), that allows more axial flexibility of the seal.
• FIG. 22 shows, in solid lines,[0114]seal868 in a disengaged position in which rimportion870 is not engaged with workpiece W. FIG. 22 also shows, in phantom lines, an engaged position in which rimportion870 is engaged with and forms a seal relative to workpiece W. Preferably and advantageously,electrode contact858 is maintained in a generally retracted position withinseal868 when the finger assembly is in the disengaged position. However, when the finger assembly is moved into the engaged position, seal868 andrim portion870 thereof splay outwardly or otherwise yieldably deform to effectively enable the electrode and henceelectrode contact858 to move into the engaged position against the workpiece. One factor which assists in forming the preferred seal between the rim portion and the workpiece is the force which is developed byspring842 which advantageously urgescollet840 and hencefinger860 andfinger tip858 in the direction of and against the captured workpiece. Such developed force assists in maintaining the integrity of the seal which is developed in the engaged position. Another factor which assists in forming the preferred seal is the yieldability or deformability of the finger tip when it is brought into contact with the workpiece. Such factors effectively create a continuous seal about the periphery ofelectrode contact858 thereby protecting it from any materials, such as the preferred plating materials which are used during electroplate processing.
Methods and Operation
• In accordance with a preferred processing aspect of the present invention, and in connection with the above-described semiconductor workpiece holder, a sheathed electrode, such as[0115]electrode860, is positioned against a semiconductor workpiece surface in a manner which permits the electrode to impart a voltage bias and current flow to the workpiece to effectuate preferred electroplating processing of the workpiece. Such positioning not only allows a desired electrical bias to be imparted to a held workpiece, but also allows the workpiece itself to be mechanically held or fixed relative to the workpiece holder. That is,finger assembly824 provides an electrical/mechanical connection between a workpiece and the workpiece holder as is discussed in more detail below.
• [0116]Electrode856 includes an electrode tip orelectrode contact858 which engages the workpiece surface. A seal is thus formed about the periphery of the electrode tip or contact858 so that a desired electrical bias may be imparted to the workpiece to enable plating material to be plated the thereon. According to a preferred aspect of the processing method, the electrode is moved in a first direction, preferably longitudinally along a movement axis, away from a disengaged position in which the workpiece surface is not engaged by the electrode tip or contact858. Subsequently, the electrode is rotated about the same movement axis and toward an engaged position in which the electrode tip may engage, so as to fix, and thereafter bias the workpiece surface. Such preferred movement is effectuated bypneumatic linkage825 andpneumatic operator871 as described above.
• According to a preferred aspect of the invention, the seal which is effectuated between the electrode member and the workpiece is formed by utilizing a yieldable,[0117]deformable seal member868 which includes arim portion870. Therim portion870 serves by contacting the workpiece surface to form a continuous seal as shown in FIG8. The preferred electrode tip is brought into engagement with the workpiece surface by advancing the electrode tip from a retracted position within the seal or other sheath to an unretracted position in which the workpiece surface is engaged thereby. Such movement of the electrode tip between the retracted and unretracted positions is advantageously accommodated by the yieldable features of theseal868.
• In addition to providing the preferred electrical contact between the workpiece and the electrode tip, the finger assembly also forms a mechanical contact or connection between the assembly and the workpiece which effectively fixes the workpiece relative to the workpiece holder. Such is advantageous because one aspect of the preferred processing method includes rotating the workpiece about[0118]rotor axis822 while the workpiece is exposed to the preferred plating material. Such not only ensures that the electrical connection and hence the electrical bias relative to the workpiece is maintained during processing, but that the mechanical fixation of the workpiece on the workpiece holder is maintained as well.
• The above described pneumatically effectuated movement of the preferred finger assemblies between the engaged and disengaged positions is but one manner of effectuating such movement. Other manners of effectuating such movement are possible[0119]
• The invention also includes novel methods for presenting a workpiece to a semiconductor process. In such methods, a workpiece is first secured to a workpiece holder. The methods work equally well for workpiece holders known in the art and for the novel workpiece holders disclosed herein.[0120]
• In the next step in the sequence, the workpiece holder is rotated about a horizontal axis from an initial or first position where the workpiece holder was provided with the workpiece to a second position. The second position will be at an angle to the horizontal. The angle of the workpiece holder to the horizontal is defined by the angle between the plane of the workpiece and the horizontal. In the method, the workpiece holder is advantageously suspended about a second horizontal axis which is parallel to the first horizontal axis of the workpiece holder. At this point in the method, the angle between the first and second horizontal axes and a horizontal plane corresponds to the angle between the workpiece holder and the horizontal. The workpiece holder is then pivoted about the second horizontal axis to move the workpiece and the workpiece holder from its initial location to a final location in a horizontal plane. Advantageously, when the workpiece holder is pivoted about the second horizontal axis, the first horizontal axis also pivots about the second horizontal axis.[0121]
• Preferably, during the step of rotating the workpiece holder about the first horizontal axis, the angle of the workpiece holder with respect to some known point, which is fixed with respect to the workpiece holder during the rotation process, is continually monitored. Monitoring allows for precise positioning of the workpiece holder with respect to the horizontal surface.[0122]
• Likewise, during pivoting of the workpiece holder about the second horizontal axis, it is preferable that the angle defined by the line connecting the first and second horizontal axes and the horizontal plane be continually monitored. In this manner, the absolute position of the workpiece holder (and hence the workpiece itself) will be known with respect to the horizontal plane. This is important since the horizontal plane typically will contain the process to which the workpiece will be exposed.[0123]
• It should be noted that in the above and following description, while the workpiece is described as being presented to a horizontal plane, it is possible that the workpiece may also be presented to a vertical plane or a plane at any angle between the vertical and the horizontal. Typically, the processing plane will be a horizontal plane due to the desire to avoid gravitational effects on process fluids to which the workpiece is exposed. In one embodiment after the workpiece has been presented to the processing plane, the workpiece holder is rotated about a spin axis to cause the workpiece to spin in the horizontal plane. Although not required in all semiconductor manufacturing processes, this is a common step which may be added in the appropriate circumstance.[0124]
• The next advantageous step in the method consists of pivoting the workpiece holder about the second horizontal axis back along the path that the workpiece holder was initially pivoted along when presenting the workpiece to the horizontal process plane. There is no requirement that the workpiece holder be pivoted back to the same position whence it began, although doing so may have certain advantages as more fully described below.[0125]
• The method advantageously further consists of the step of rotating the workpiece holder about the first horizontal axis to return the workpiece to the position when it was initially presented to and engaged by the workpiece holder. It is advantageous to rotate the workpiece holder about the first axis in a direction opposite from the initial rotation of the workpiece holder.[0126]
• The advantage of having the workpiece holder terminate at an end position which corresponds to the initial position when the workpiece was loaded into the workpiece holder is efficiency. That is, additional machine movements are not required to position the workpiece holder to receive a new workpiece.[0127]
• The method more preferably includes the step of rotating the workpiece holder about the first horizontal axis at at least two support points along the first horizontal axis. This beneficially provides support and stability to the workpiece holder during the rotation process and subsequent movement of the apparatus.[0128]
• The method also more preferably includes the step of pivoting the workpiece holder along with the first horizontal axis about the second horizontal axis at at least two support points along the second horizontal axis. This beneficially provides additional support for the workpiece holder while allowing the workpiece holder to be moved in a vertical or “Z-axis” direction.[0129]
• Importantly, the only motion described in the above method is rotational motion about several axes. In the method described, there is no translational motion of the workpiece holder in a X-, Y-, or Z-axis without corresponding movement in another axis as a result of rotating through an arc.[0130]
• In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.[0131]

Claims (7)

1. A workpiece holder for use in processing a workpiece comprising:

a workpiece support;

at least one finger assembly mounted upon said workpiece support; said at least one finger assembly including at least one contact for contacting the workpiece;

at least one finger actuator operable with said at least one finger assembly for moving said finger assembly between an engaged position wherein said finger assembly is in contact with the workpiece and a disengaged position wherein said finger assembly is disengaged from the workpiece, said at least one finger actuator having means for moving the at least one finger assembly in an axial movement toward and from the workpiece along a longitudinal axis, and means to rotate the at least one finger assembly in a rotational movement about said longitudinal axis;

at least one electrode forming a part of said at least one finger assembly, said at least one electrode having an electrode contact for contacting a surface of said workpiece to provide electrical connection therewith, wherein said electrode contact is one of said at least one contact.

2. The workpiece holder ofclaim 1 wherein said at least one finger actuator moves said at least one finger assembly in a reciprocal manner.

3. The workpiece holder ofclaim 1 and further comprising at least one protective sheath covering at least a portion of the at least one finger assembly to protect the finger assembly from contact with a fluid.

4. The workpiece holder ofclaim 1 and further comprising at least one protective sheath covering at least a portion of the at least one finger assembly to protect the finger assembly from contact with a plating fluid, said at least one protective sheath being made from a dielectric material.

5. The workpiece holder ofclaim 4 wherein said at least one protective sheath includes a rim portion for engaging said workpiece and forming a seal therebetween.

6. The workpiece holder ofclaim 4 wherein said electrode contact is maintained in a generally retracted position within said at least one protective sheath when said at least one finger assembly is in said disengaged position; said electrode contact being moved out of said retracted position when said at least one finger assembly is moved into said engaged position.

7. The workpiece holder ofclaim 4 wherein said at least one protective sheath includes a yieldable terminal end adjacent said electrode contact for engaging said workpiece and effectively sealing said electrode contact therewithin when said at least one finger assembly is moved to said engaged position; wherein said electrode contact is maintained in a generally retracted position within said at least one protective sheath when said at least one finger assembly is in said disengaged position; said electrode contact being moved out of said retracted position when said finger assembly is moved into said engaged position.

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