Flexible diaphragm post-type floating and rigid abrading workholder

• US 9,199,354 B2
• Filed: 07/13/2014
• Issued: 12/01/2015
• Est. Priority Date: 10/29/2012
• Status: Active Grant

• Current Assignee: Cameron M. Duescher, Wayne O. Duescher
• Original Assignee: Cameron M. Duescher, Wayne O. Duescher
• Inventors: Duescher, Wayne O., Duescher, Cameron M.
• Primary Examiner(s): NGUYEN, GEORGE BINH MINH
• Application Number:
  US14/329,967
• Publication Number:
  US 20150024662A1
• Time in Patent Office: 506 Days
• Field of Search: 451285-290, 451/41, 451397-398
• US Class Current: 1/1
• CPC Class Codes: B24B 37/042 operating processes therefor
• CPC Class Codes: B24B 37/10 for single side lapping
• CPC Class Codes: B24B 37/105 the workpieces or work carriers being actively moved by a drive, e.g. in a combined rotary and translatory movement
• CPC Class Codes: B24B 37/30 for single side lapping of plane surfaces
• CPC Class Codes: H01L 21/304 Mechanical treatment, e.g. grinding, polishing, cutting H01L21/30625 takes precedence

Abstract

Hard-material, flat-surfaced workpieces such as semiconductor wafers or sapphire disks are quickly attached with vacuum to a rotatable floating workpiece carrier. Fluid pressure in a sealed chamber applies uniform abrading pressure over the full abraded surface of the workpieces. A flexible diaphragm is used to form the sealed chamber and the carrier is rotationally driven by a lug-pin device. The floating carrier is horizontally restrained by a center-post device that provides rigid lateral support against abrading forces. Tilting of the floating carrier is provided by a spherical bearing. The abrading system can be operated at the very high abrading speeds used in high speed flat lapping with raised-island abrasive disks. Vacuum can also be applied to the sealed chamber to quickly move the workpiece away from the abrading surface. A mode of providing rigid parallel-surface abrading of a workpiece can be activated by simply applying vacuum to the sealed chamber.

Claims

1. A rotating platen abrasive lapping and polishing apparatus having a floating workpiece substrate carrier apparatus comprising:

a) a workpiece substrate carrier frame moveable in a vertical direction supporting an attached rotatable workpiece carrier spindle having a rotatable carrier drive shaft with a vertical rotatable carrier drive shaft axis of rotation;

b) a rotatable drive housing having a rotatable drive housing rotation axis wherein the rotatable drive housing is attached to the rotatable carrier drive shaft and the rotatable drive housing rotation axis is coincident with the rotatable carrier drive shaft axis of rotation;

c) a rotatable flexible annular diaphragm device with an annular diaphragm device annular surface, an annular diaphragm device outer periphery portion, an annular diaphragm device inner periphery portion and an axis of rotation that is nominally located at the radial center of the annular diaphragm device annular surface and that is nominally perpendicular to the annular diaphragm device annular surface, wherein the annular diaphragm device outer annular periphery portion is moveable relative to the annular diaphragm device inner annular periphery portion;

d) a floating circular rotatable workpiece carrier plate having a workpiece carrier plate top surface, an opposed nominally-horizontal workpiece carrier plate flat bottom surface, a workpiece carrier plate rotation axis nominally located at the radial center of the workpiece carrier plate bottom surface and is nominally-perpendicular to the workpiece carrier plate flat bottom surface wherein the floating circular rotatable workpiece carrier plate is movable relative to the rotatable drive housing in a nominally-vertical direction along the floating circular workpiece carrier plate rotation axis and can be tilted relative to the rotatable drive housing;

e) wherein the rotatable flexible annular diaphragm device inner annular periphery portion is attached to the rotatable drive housing and the rotatable flexible annular diaphragm device outer annular periphery portion is attached to the workpiece carrier plate and the rotatable flexible annular diaphragm device axis of rotation is nominally-coincident with the vertical rotatable carrier drive shaft axis of rotation and the rotatable flexible annular diaphragm device together with the rotatable drive housing and the workpiece carrier plate forms a sealed enclosed rotatable flexible annular diaphragm device abrading pressure chamber having an internal volume contained on one side of the internal volume by the rotatable flexible annular diaphragm, the rotatable drive housing and the workpiece carrier plate;

f) a rotary workpiece drive device connected with both the rotatable drive housing and the workpiece carrier plate wherein the rotary workpiece drive device allows movement of the workpiece carrier plate relative to the rotatable drive housing and the rotary workpiece drive device transmits torque, measured about the rotatable drive housing rotation axis, from the rotatable drive housing to the workpiece carrier plate and is configured to cause the workpiece carrier plate to be rotated by the rotatable drive housing;

g) a vertical support shaft supported by at least one shaft bearing is attached to the rotatable drive housing wherein the at least one shaft bearing allows the vertical support shaft to move vertically relative to the rotatable drive housing and the at least one shaft bearing restrains the vertical support shaft in a radial direction perpendicular to the rotatable drive housing rotation axis;

h) a spherical-action bearing having a spherical-action bearing inner race and a spherical-action bearing outer race, wherein the inner race of the spherical-action bearing is attached to the vertical support shaft and the outer race of the spherical-action bearing is attached to the workpiece carrier plate, wherein the spherical-action bearing allows the workpiece carrier plate to be tilted relative to the rotatable drive housing and wherein the spherical-action bearing restrains the workpiece carrier plate in a radial direction that is nominally-perpendicular to the workpiece carrier plate rotation axis and wherein the spherical-action bearing maintains the floating circular workpiece carrier plate rotation axis as nominally concentric with the carrier drive shaft axis of rotation;

i) a vacuum and fluid rotatable rotary union device that is attached to the rotatable workpiece carrier spindle wherein the vacuum and fluid rotatable rotary union device supplies vacuum or pressurized fluid through fluid passageways to vacuum port holes in the workpiece carrier plate that are open on the workpiece carrier plate flat bottom surface and wherein the vacuum and fluid rotatable rotary union supplies vacuum or pressurized fluid through fluid passageways to the sealed flexible-diaphragm pressure chamber;

j) wherein the floating circular rotatable workpiece carrier plate is movable relative to the workpiece substrate carrier frame in a nominally-vertical direction along the floating circular workpiece carrier plate rotation axis and can be tilted relative to the workpiece substrate carrier frame;

k) a flat-surfaced rotatable abrading platen having the flat surface of the rotatable abrading platen is nominally horizontal and has an abrasive coating;

l) wherein at least one workpiece having opposed workpiece nominally-flat top and bottom surfaces has the workpiece nominally-flat top surface vacuum-attached to the workpiece carrier plate flat bottom surface and wherein the nominally-flat bottom surface of the at least one attached workpiece can be held in flat-surfaced abrading contact with the abrasive coating on the rotatable abrading platen.

2. The apparatus of claim 1 wherein the rotary workpiece drive device comprises a rotatable drive housing bracket attached to the rotatable drive housing, and a workpiece carrier plate bracket attached to the workpiece carrier plate, wherein the rotatable drive housing bracket and the workpiece carrier plate bracket are in vertical and horizontal sliding contact with each other at a bracket sliding joint and wherein the rotary drive housing bracket can be rotated by the rotatable drive housing to transmit torque, measured about the rotatable drive housing rotation axis, through the bracket sliding joint to the workpiece carrier plate bracket to provide rotation of the workpiece carrier plate about the workpiece carrier plate rotation axis, and wherein the workpiece carrier plate is movable vertically in a direction along the workpiece carrier plate rotation axis and wherein the workpiece carrier plate is tiltable relative to the rotatable drive housing.

3. The apparatus of claim 1 wherein the rotary workpiece drive device comprises:

a) at least one nominally-horizontal rotatable nominally-circular flexible support element having at least one individual flexible arm wherein the at least one flexible arm has a first proximal end secured to a central support ring, and a second distal end connected to a respective first proximal end by a flexing joint;

b) wherein the second distal end is flexible in a vertical direction but is stiff in a direction that is tangential to the nominally-circular flexible support element and wherein the flexible support element has a nominally-vertical rotatable flexible support element rotation axis located at a center of the nominally-circular flexible support element;

c) the at least one rotatable nominally-circular flexible support element central support ring is attached to the rotatable drive housing and the at least one flexible support element second distal end is attached to the floating circular rotatable workpiece carrier plate and the at least one rotatable flexible support element rotation axis is coincident with the rotatable drive housing rotation axis; and

d) the at least one rotatable nominally-circular flexible support element is rotatable by the rotatable drive housing to provide rotation of the workpiece carrier plate, and the workpiece carrier plate is movable vertically in a direction along the workpiece carrier plate rotation axis by flexing the at least one individual flexible radial arm in a vertical direction.

4. The apparatus of claim 1 wherein the rotatable flexible annular diaphragm device comprises flexible materials selected from the group consisting of:

elastomers, silicone rubber, room temperature vulcanizing silicone rubber, natural rubber, synthetic rubber, thermoset polyurethane, thermoplastic polyurethane, flexible polymers, composite materials, polymer-impregnated woven cloths, sealed fiber materials, laminated sheets of combinations thereof, sheets of impervious flexible materials, and metals.

5. The apparatus of claim 1 wherein pressure-controlled air, fluid or vacuum is accessible into the sealed flexible-diaphragm pressure chamber through a passageway connecting an air, fluid or vacuum passageway in the rotatable carrier drive shaft to the sealed flexible-diaphragm pressure chamber and wherein the pressure or vacuum present in the sealed flexible-diaphragm pressure chamber is sufficient to move the workpiece carrier plate vertically and wherein controlled pressure present in the sealed flexible-diaphragm pressure chamber applies a controlled abrading pressure to workpieces that are attached to the workpiece carrier plate that is in abrading contact with the rotatable abrading platen abrasive coated abrading surface.

6. The apparatus of claim 1 wherein the workpiece carrier plate top surface is configured so that controlled vacuum applied to the sealed flexible-diaphragm pressure chamber generates a lifting force on the workpiece carrier plate capable of moving the workpiece carrier plate toward the rotatable drive housing thereby distorting the rotatable flexible annular diaphragm device in a direction along the flexible annular diaphragm device axis of rotation wherein the workpiece carrier plate and the at least one workpiece that is attached with vacuum to the workpiece carrier plate are moved vertically away from the rotatable abrading platen abrasive coated abrading surface.

7. The apparatus of claim 2 wherein the rotatable drive housing bracket and the workpiece carrier plate bracket act together in mutual sliding contact to rotate the workpiece carrier plate in either clockwise or counterclockwise directions and to rotationally accelerate or decelerate the workpiece carrier and wherein the rotatable drive housing bracket and the workpiece carrier plate bracket act together to prevent substantial rotation of the workpiece carrier plate relative to the rotatable drive housing.

8. The apparatus of claim 1 wherein the rotatable drive housing and the floating circular rotatable workpiece carrier plate have mutually-acting floating circular rotatable workpiece carrier plate vertical excursion-stop devices wherein the vertical movement distance of the floating circular rotatable workpiece carrier plate relative to the rotatable drive housing is controlled and limited by contact of the rotatable drive housing vertical excursion-stop device with the floating circular rotatable workpiece carrier plate vertical excursion-stop device and the angular tilting arc distance of the workpiece carrier plate relative to the rotatable drive housing is controlled and limited by a rotatable drive housing angular-arc excursion-stop device.

9. A process for using the apparatus of claim 1 to abrade or polish a workpiece wherein the workpiece carrier plate and at least one workpiece that is attached by vacuum to the workpieces carrier plate are moved vertically wherein the at least one workpiece flat bottom surface is held with controlled abrading-pressure in flat-surfaced abrading contact with the rotatable abrading platen flat abrasive coating and both the rotatable abrading platen having the flat abrasive coated abrading surface and the workpiece carrier plate having the attached workpiece are rotated.

10. A process for the apparatus of claim 5 to abrade or polish a workpiece surface wherein pressurized air or a fluid is supplied to the sealed flexible-diaphragm pressure chamber wherein the air or a fluid pressure acts on the workpiece carrier plate top surface and wherein the air or a fluid pressure is transmitted through the workpiece carrier plate thickness wherein the air or a fluid pressure is applied to at least one workpiece that is attached to the workpiece carrier plate which forces the at least one workpiece into controlled abrading-pressure flat-surfaced abrading contact with the rotatable abrading platen abrasive surface.

11. A process for using the apparatus of claim 5 to abrade or polish a workpiece surface wherein vacuum is applied to the sealed flexible-diaphragm pressure chamber to generate a vacuum lifting force on the workpiece carrier plate wherein the vacuum lifting force forces the workpiece carrier plate top surface into rigid contact against a rotatable drive housing vertical excursion-stop device attached to the rotatable drive housing and wherein the workpiece substrate carrier frame and the attached workpiece carrier spindle are moved vertically to position the at least one workpiece that is attached to the workpiece carrier plate flat bottom surface into abrading contact with the rotatable abrading platen abrasive surface, and the at least one workpiece surface is abraded or polished by rotating the rotatable abrading platen and rotating the workpiece carrier plate while the at least one workpiece is in abrading contact with the platen abrasive surface.

12. The apparatus of claim 5 wherein central portions of the floating circular rotatable workpiece carrier plate are flexible in a vertical direction and wherein the workpiece carrier plate outer periphery annular surface is substantially rigid in a horizontal direction, wherein the flexible central portions of the workpiece carrier plate flat bottom surface can be distorted out-of-plane by the pressure-controlled air, fluid or vacuum present in the sealed flexible-diaphragm pressure chamber.

13. The apparatus of claim 12 wherein multiple rotatable flexible annular diaphragm devices are positioned concentric with respect to each other to form multiple independent annular or circular rotatable flexible annular diaphragm devices with sealed flexible-diaphragm pressure chambers comprising:

a) independent annular or circular sealed flexible pressure chambers formed radially outward from the rotational center of the flexible rotatable workpiece carrier plate wherein respective independent sealed flexible-diaphragm pressure chambers are adjacent to each other;

b) independent sealed flexible-diaphragm pressure chambers have an independent controlled-pressure air or controlled-pressure fluid or vacuum source supplied by a multi-port vacuum and fluid rotatable rotary union attached to the rotatable workpiece carrier spindle to provide independent pressure-controlled air or fluid pressures to respective rotatable flexible annular diaphragm device'"'"'s sealed flexible-diaphragm pressure chambers;

c) the flexible central portions of the workpiece carrier plate nominally-flat bottom surface can assume non-flat shapes at the location of each independent rotatable flexible annular diaphragm device'"'"'s sealed flexible-diaphragm pressure chamber;

d) each of the independent rotatable flexible annular diaphragm device'"'"'s sealed flexible-diaphragm pressure chambers apply independently controlled abrading pressures to respective portions of an abraded surface of a workpiece vacuum-attached to the workpiece carrier plate at the locations of the respective rotatable flexible annular diaphragm device'"'"'s sealed flexible-diaphragm pressure chambers when the workpiece abraded surface is in abrading contact with the rotatable abrading platen abrading surface.

14. The apparatus of claim 1 wherein the vacuum and fluid rotatable rotary union attached to the workpiece carrier spindle is a friction-free air-bearing rotary union.

15. The apparatus of claim 6 wherein vacuum supplied to the sealed flexible-diaphragm pressure chamber which generates a lifting force on the workpiece carrier plate that is configured to move the workpiece carrier plate toward the rotatable drive housing is provided by a vacuum surge tank having a substantial tank volume, wherein the at least one workpiece attached to the workpiece carrier plate is moved away from abrading contact with the rotatable abrading platen abrading surface.

16. The apparatus of claim 1 wherein the rotatable flexible annular diaphragm device has non-planar annular surface curvatures which is configured to increase its flexibility in a radial direction perpendicular to the flexible annular diaphragm device axis of rotation and increases its flexibility in a horizontal direction.

17. The apparatus of claim 1 wherein at least one measurement device is attached to the workpiece substrate carrier frame to measure the distance between the workpiece substrate carrier frame and the workpiece carrier plate when the at least one workpiece that is attached to the workpiece carrier plate is in flat-surfaced contact with the rotatable abrading platen abrading surface and wherein the at least one measurement device enables monitoring i) an amount of material removed from the at least one workpiece and ii) a rate of material removal from the at least one workpiece that is attached to the workpiece carrier plate when the at least one workpiece is in abrading contact with the rotating or stationary rotatable abrading platen abrading surface.

18. The apparatus of claim 8 wherein at least one measurement device is attached to the workpiece substrate carrier frame and is configured to measure a distance between the workpiece substrate carrier frame and the workpiece carrier plate when the at least one workpiece that is attached to the workpiece carrier plate is in flat-surfaced contact with the rotatable abrading platen abrading surface wherein the distance measurements between the workpiece substrate carrier frame and the workpiece carrier plate are used to move the workpiece carrier plate workpiece substrate carrier frame vertically wherein the workpiece carrier plate is positioned vertically and a vertical movement distance of the floating circular rotatable workpiece carrier plate relative to the rotatable drive housing that is attached to the workpiece substrate carrier frame is approximately at the midpoint of a controlled and limited vertical movement distance of the floating circular rotatable workpiece carrier plate relative to the rotatable drive housing controlled by the vertical excursion-stop devices.

19. The apparatus of claim 1 wherein the spherical-action bearing has a spherical-center of rotation located approximately where the attached workpiece nominally-flat bottom surface is in abrading contact with the abrasive coating on the rotatable abrading platen.

20. The apparatus of claim 1 wherein the abrasive coating on the rotatable abrading platen is provided by flexible fixed-abrasive raised-island disks having annular bands of raised-island structures with recessed passageways between individual raised islands wherein the raised-island structures are top-coated with bonded abrasive particles and wherein the flexible fixed-abrasive raised-island disks are attached with vacuum to the flat surface of the rotatable abrading platen.

21. The apparatus of claim 1 wherein a first fluid tube or fluid passageway located in the carrier drive shaft that is supplied vacuum or pressurized fluid by the vacuum and fluid rotatable rotary union is connected to a pressure or vacuum sealed slidable fluid joint device wherein a second fluid tube or fluid passageway is connected with the pressure or vacuum sealed slidable fluid joint device and the second fluid tube or fluid passageway is also connected with the vacuum port holes in the workpiece carrier plate to provide vacuum or fluid pressure to the vacuum port holes in the workpiece carrier plate and wherein either the first fluid tube or fluid passageway or the second fluid tube or fluid passageway is moveable within confines of the pressure or vacuum sealed slidable fluid joint device and wherein the vacuum or pressurized fluid is maintained at the vacuum port holes in the workpiece carrier plate when the floating circular rotatable workpiece carrier plate is moved relative to the rotatable drive housing in a nominally-vertical direction.

22. The apparatus of claim 1 wherein a first fluid tube or fluid passageway located in the carrier drive shaft that is supplied vacuum or pressurized fluid by the vacuum and fluid rotatable rotary union is connected to a pressure or vacuum sealed slidable fluid joint device wherein a second fluid tube or fluid passageway is connected with the pressure or vacuum sealed slidable fluid joint device and the second fluid tube or fluid passageway is also connected with the sealed flexible-diaphragm pressure chamber and wherein either the first fluid tube or fluid passageway or the second fluid tube or fluid passageway is moveable within the confines of the pressure or vacuum sealed slidable fluid joint device and wherein the vacuum or fluid pressure is maintained at the sealed flexible-diaphragm pressure chamber when the floating circular rotatable workpiece carrier plate is moved relative to the rotatable drive housing in a nominally-vertical direction.

23. A process of providing abrading workpieces using an abrading machine floating workpiece substrate carrier apparatus comprising:

a) providing a workpiece substrate carrier frame moveable in a vertical direction that supports an attached rotatable workpiece carrier spindle having a rotatable carrier drive shaft with a vertical rotatable carrier drive shaft axis of rotation;

b) providing a rotatable drive housing having a rotatable drive housing rotation axis wherein the rotatable drive housing is attached to the rotatable carrier drive shaft and the rotatable drive housing rotation axis is coincident with the rotatable carrier drive shaft axis of rotation;

c) providing a rotatable flexible annular diaphragm device with an annular diaphragm device annular surface, an annular diaphragm device outer periphery portion, an annular diaphragm device inner periphery portion and an axis of rotation that is nominally located at a radial center of the annular diaphragm device annular surface and that is nominally perpendicular to the annular diaphragm device annular surface, wherein the annular diaphragm device outer annular periphery portion is moveable relative to the annular diaphragm device inner annular periphery portion;

d) providing a floating circular rotatable workpiece carrier plate having a workpiece carrier plate top surface, an opposed nominally-horizontal workpiece carrier plate flat bottom surface, a workpiece carrier plate rotation axis nominally located at the radial center of the workpiece carrier plate bottom surface and is nominally-perpendicular to the workpiece carrier plate flat bottom surface wherein the floating circular rotatable workpiece carrier plate is movable relative to the rotatable drive housing in a nominally-vertical direction along the floating circular workpiece carrier plate rotation axis and can be tilted relative to the rotatable drive housing;

e) attaching the rotatable flexible annular diaphragm device inner annular periphery portion to the rotatable drive housing and attaching the rotatable flexible annular diaphragm device outer annular periphery portion to the workpiece carrier plate and the rotatable flexible annular diaphragm device axis of rotation is nominally-coincident with the vertical rotatable carrier drive shaft axis of rotation and the rotatable flexible annular diaphragm device together with the rotatable drive housing and the workpiece carrier plate forms a sealed enclosed rotatable flexible annular diaphragm device abrading pressure chamber having an internal volume contained by the rotatable flexible annular diaphragm, the rotatable drive housing and the workpiece carrier plate;

f) providing a rotary workpiece drive device that is connected with both the rotatable drive housing and the workpiece carrier plate wherein the rotary workpiece drive device allows movement of the workpiece carrier plate relative to the rotatable drive housing and wherein the rotary workpiece drive device transmits torque, measured about the rotatable drive housing rotation axis, from the rotatable drive housing to the workpiece carrier plate and is configured to cause the workpiece carrier plate to be rotated by the rotatable drive housing;

g) providing a vertical support shaft supported by at least one shaft bearing that is attached to the rotatable drive housing wherein the at least one shaft bearing allows the vertical support shaft to move vertically relative to the rotatable drive housing and the at least one shaft bearing restrains the vertical support shaft in a radial direction that is perpendicular to the rotatable drive housing rotation axis;

h) providing a spherical-action bearing having a spherical-action bearing inner race and a spherical-action bearing outer race wherein the inner race of the spherical-action bearing is attached to the vertical support shaft and the outer race of the spherical-action bearing is attached to the workpiece carrier plate wherein the spherical-action bearing allows the workpiece carrier plate to be tilted relative to the rotatable drive housing and wherein the spherical-action bearing restrains the workpiece carrier plate in radial direction that is nominally-perpendicular to the workpiece carrier plate rotation axis and wherein the spherical-action bearing maintains the floating circular workpiece carrier plate rotation axis as nominally concentric with the carrier drive shaft axis of rotation;

i) providing a vacuum and fluid rotatable rotary union device that is attached to the rotatable workpiece carrier spindle wherein the vacuum and fluid rotatable rotary union device applies vacuum or pressurized fluid through fluid passageways to vacuum port holes in the workpiece carrier plate that are open on the workpiece carrier plate flat bottom surface and wherein the vacuum and fluid rotatable rotary union applies vacuum or pressurized fluid through fluid passageways to the sealed flexible-diaphragm pressure chamber;

j) the floating circular rotatable workpiece carrier plate is movable relative to the workpiece substrate carrier frame in a nominally-vertical direction along the floating circular workpiece carrier plate rotation axis and can be tilted relative to the workpiece substrate carrier frame;

k) providing a flat-surfaced rotatable abrading platen where the flat surface of the rotatable abrading platen is nominally horizontal and has an abrasive coating;

l) providing at least one workpiece having opposed workpiece nominally-flat top and bottom surfaces and using vacuum to attach the workpiece nominally-flat top surface to the workpiece carrier plate flat bottom surface;

m) moving the workpiece substrate carrier frame and the attached workpiece carrier spindle vertically to position the flat workpiece bottom surface of at least one workpiece attached to the workpiece carrier plate flat bottom surface close to flat-surfaced abrading contact with the rotatable abrading platen abrading surface after which the movable workpiece substrate carrier frame and the workpiece carrier spindle are held stationary at that position and wherein the workpiece carrier plate is moved in a vertical direction relative to the stationary workpiece substrate carrier frame by adjusting the pressure in the sealed flexible-diaphragm pressure chamber wherein the at least one workpiece bottom surface is positioned in flat-surfaced abrading contact with the rotatable abrading platen abrading surface; and

n) rotating both the workpiece carrier plate having the attached at least one workpiece and the abrasive-coated flat-surfaced rotatable abrading platen, wherein the sealed flexible-diaphragm pressure chamber provides controlled abrading pressure to the at least one workpiece to abrade the at least one workpiece.