Flexible diaphragm combination floating and rigid abrading workholder

• US 9,011,207 B2
• Filed: 02/20/2014
• Issued: 04/21/2015
• Est. Priority Date: 10/29/2012
• Status: Expired due to Fees

• Current Assignee: Wayne O. Duescher
• Original Assignee: Wayne O. Duescher
• Inventors: Duescher, Wayne O.
• Primary Examiner(s): NGUYEN, GEORGE BINH MINH
• Application Number:
  US14/185,882
• Publication Number:
  US 20140170938A1
• Time in Patent Office: 425 Days
• Field of Search: 451285-290, 451/41, 451397-398
• US Class Current: 451/41
• CPC Class Codes: B24B 37/042 operating processes therefor
• CPC Class Codes: B24B 37/10 for single side lapping
• CPC Class Codes: B24B 37/30 for single side lapping of plane surfaces
• CPC Class Codes: B24B 37/32 Retaining rings
• CPC Class Codes: H01L 21/304 Mechanical treatment, e.g. grinding, polishing, cutting H01L21/30625 takes precedence

Abstract

Flat-surfaced workpieces such as semiconductor wafers or sapphire disks are attached to a rotatable floating or rigid workpiece holder carrier that is supported by a pressurized-air flexible elastomer disk sealed air-chamber device and is rotationally driven by a flexible arm or a lug-pin device. The rotating wafer carrier rotor is horizontally restrained by a set of idlers that are attached to a stationary housing to provide rigid support against abrading forces. The abrading system can be operated at the very high abrading speeds used in high speed flat lapping with raised-island abrasive disks. A wide range of abrading pressures are applied uniformly across the surface of the workpiece. Vacuum can also be applied to the elastomer chamber to quickly move the wafer away from the abrading surface. Internal constraints limit the axial, lateral and circumferential motion of the workholder. Wafers can be quickly attached to the workpiece carrier with vacuum.

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 that supports an attached rotatable workpiece carrier spindle having a hollow 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 disk device with an annular disk device annular surface, an annular disk device outer periphery portion, an annular disk device inner periphery portion and an axis of rotation that is nominally located at the radial center of the annular disk device annular surface and that is nominally perpendicular to the annular disk device annular surface, wherein the annular disk device outer annular periphery portion is moveable relative to the annular disk 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-perpendicular to the workpiece carrier plate flat bottom surface and a workpiece carrier plate nominally-vertical outer periphery annular surface located between the workpiece carrier plate top and bottom surfaces, wherein the floating circular rotatable workpiece carrier plate is movable relative to the rotatable drive housing;

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

f) 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) at least two rotatable idlers having rotation axes wherein the rotatable idlers have outer periphery cylindrical or spherical surfaces that are rotatable about the rotatable idlers rotation axes;

h) wherein the at least two rotatable idlers are attached to the movable workpiece substrate carrier frame and the at least two rotatable idlers'"'"' rotation axes are nominally parallel to the vertical rotatable carrier drive shaft axis of rotation and the at least two respective rotatable idler'"'"'s outer periphery cylindrical or spherical surfaces contact the floating circular workpiece carrier plate outer periphery annular surface, wherein the at least two rotatable idlers maintain the floating circular workpiece carrier plate rotation axis as nominally concentric with the carrier drive shaft axis of rotation;

i) wherein the floating circular workpiece carrier plate is moveable relative to the movable workpiece substrate carrier frame in a nominally-vertical direction along the floating circular workpiece carrier plate rotation axis wherein the at least two respective rotatable idler'"'"'s outer periphery cylindrical surfaces are in vertical sliding contact with the floating circular workpiece carrier plate outer periphery annular surface and the at least two rotatable idlers rotate in contact with the rotating rotatable workpiece carrier plate; and

j) wherein at least one workpiece having opposed workpiece top and bottom surfaces is attached to the workpiece carrier plate flat bottom surface and a rotatable abrading platen having a flat abrasive coated abrading surface that is nominally horizontal.

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 the workpiece carrier plate is movable horizontally in a direction perpendicular to the workpiece carrier plate rotation axis.

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 each arm has a first proximal end secured to a central support ring, and a second distal end connected to the 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) wherein 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 can be rotated 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 disk 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 enclosed flexible annular disk device pressure chamber through a passageway connecting an air, fluid or vacuum passageway in the hollow rotatable carrier drive shaft to the enclosed flexible annular disk device pressure chamber and wherein the pressure or vacuum present in the enclosed flexible annular disk device pressure chamber is sufficient to move the workpiece carrier plate vertically and wherein controlled pressure present in the enclosed flexible annular disk device pressure chamber applies a controlled abrading pressure to workpieces that attached to the workpiece carrier plate that are in abrading contact with a 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 enclosed flexible annular disk device 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 disk device in a direction along the flexible annular disk device axis of rotation wherein the workpiece carrier plate is 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 with mutual sliding contact to rotate the workpiece carrier plate in either clockwise and counterclockwise directions and to rotationally accelerate and 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 3 wherein the horizontal rotatable nominally-circular flexible support element is configured to rotate the workpiece carrier in either clockwise or counterclockwise directions and rotationally accelerate or decelerate the workpiece carrier and wherein the horizontal rotatable nominally-circular flexible support.

9. The apparatus of claim 1 wherein the rotatable drive housing has an attached rotatable drive housing vertical excursion-stop device and an attached rotatable drive housing horizontal excursion-stop device, and the floating circular rotatable workpiece carrier plate has an attached floating circular rotatable workpiece carrier plate vertical excursion-stop device and an attached floating circular rotatable workpiece carrier plate horizontal excursion-stop device, wherein the horizontal and 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 by contact of the rotatable drive housing horizontal excursion-stop device with the floating circular rotatable workpiece carrier plate horizontal excursion-stop device.

10. The apparatus of claim 1 wherein a rotatable stationary vacuum, air or fluid rotary union is attached to the hollow carrier drive shaft to supply vacuum, pressurized air or fluid to a hollow carrier drive shaft fluid passageway connected to a hollow flexible fluid tube that is routed to fluid passageways connected to vacuum or fluid port holes in the workpiece carrier plate flat bottom surface to supply vacuum, pressurized air or pressurized fluid to the port holes in the workpiece carrier plate flat bottom surface.

11. The apparatus of claim 1 wherein a rotatable stationary vacuum, air or fluid rotary union is attached to the hollow carrier drive shaft which supplies vacuum, pressurized air or pressurized fluid to a hollow carrier drive shaft fluid passageway that is routed to the sealed flexible annular disk device pressure chamber to supply vacuum, pressurized air or pressurized fluid to the sealed flexible annular disk device pressure chamber.

12. The apparatus of claim 3 further comprising a rotational limiting and restraint device in conjunction with the circular flexible support element, wherein the rotational limiting and restraint device is attached to either the rotatable workpiece carrier plate or to the rotatable drive housing, wherein the rotational limiting and restraint device contacts only a respective adjacent rotatable workpiece carrier plate or the respective adjacent rotatable drive housing when the flexible support element is substantially distorted or fractured, wherein the rotational limiting and restraint device prevents substantial rotation of the rotatable workpiece carrier plate relative to the rotatable drive housing.

13. A process for using the apparatus of claim 10 to abrade or polish a workpiece surface by rotating the rotatable abrading platen having a flat abrasive coated abrading surface against a workpiece wherein vacuum is supplied to the hollow flexible fluid tube that is routed to fluid passageways connected to vacuum or fluid port holes in the workpiece carrier plate flat bottom surface wherein the vacuum attaches at least one workpiece to the workpiece carrier plate flat bottom surface.

14. 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 annular disk device pressure chamber so that the applied pressure acts on the workpiece carrier plate top surface and with the workpiece is in abrading contact with the platen abrasive to create an abrading force that is transmitted through the workpiece carrier plate thickness wherein this abrading force is transmitted to at least one workpiece that is attached to the workpiece carrier plate which forces the at least one workpiece into abrading-force controlled flat-surfaced abrading contact with the rotatable abrading platen abrasive surface.

15. A process for using the apparatus of claim 5 to abrade or polish a workpiece surface wherein vacuum is applied to the sealed enclosed flexible annular disk device 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 workpiece that is attached to the workpiece carrier plate flat bottom surface into abrading contact with the rotatable abrading platen abrasive surface, and the workpiece surface is abraded or polished by rotating the rotatable abrading platen and rotating the workpiece carrier plate while the workpiece is in abrading contact with the platen abrasive surface.

16. The apparatus of claim 5 wherein central portions of the floating circular rotatable workpiece carrier plate 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 enclosed flexible annular disk device pressure chamber.

17. The apparatus of claim 16 wherein multiple rotatable flexible annular disk devices are positioned concentric with respect to each other to form multiple independent annular or circular rotatable flexible annular disk device'"'"'s sealed flexible annular disk device pressure chambers wherein independent sealed flexible annular disk device pressure chambers are formed between adjacent sealed flexible annular disk device pressure chambers, wherein each independent sealed rotatable flexible annular disk device sealed enclosed pressure chamber has an independent controlled-pressure air or controlled-pressure fluid or vacuum source to provide independent pressure-controlled air or fluid pressures to respective rotatable flexible annular disk device'"'"'s sealed enclosed pressure chambers, wherein the flexible central portions of the workpiece carrier plate flat bottom surface can assume non-flat shapes at the location of each independent rotatable flexible annular disk device'"'"'s sealed enclosed pressure chamber and the respective rotatable flexible annular disk device'"'"'s sealed enclosed pressure chambers apply independently controlled abrading pressures to the portions of the abraded surface of at least one workpiece that is attached to the workpiece carrier plate at a position of the respective rotatable flexible annular disk device'"'"'s sealed enclosed pressure chambers when the at least one workpiece abraded surface is in abrading contact with the rotatable abrading platen abrading surface.

18. The apparatus of claim 16 wherein the flexible-bottom workpiece carrier plate has an attached flexible vacuum-surface device that extends over the workpiece-attachment nominally-flat central portions of the floating circular rotatable workpiece carrier plate wherein the attached flexible vacuum-surface device has vacuum port holes wherein vacuum attaches a workpiece to the flexible-bottom workpiece carrier plate by vacuum supplied to the vacuum port holes.

19. The apparatus of claim 1 wherein the floating workpiece carrier plate nominally-vertical outer periphery annular surface has a nominally-spherical shape.

20. The apparatus of claim 10 wherein the stationary vacuum and fluid rotary union attached to the hollow rotatable carrier drive shaft is a friction-free air-bearing rotary union.

21. The apparatus of claim 11 wherein the stationary vacuum and fluid rotary union attached to the hollow rotatable carrier drive shaft is a friction-free air-bearing rotary union.

22. The apparatus of claim 6 wherein vacuum supplied to the sealed enclosed flexible annular disk device pressure chamber which generates a lifting force on the workpiece carrier plate that is capable of moving 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 that is attached to the workpiece carrier plate is moved away from abrading contact with the rotatable abrading platen abrading surface.

23. The apparatus of claim 1 wherein the rotatable flexible annular disk device has an non-planar annular surface curvature which increases its flexibility in a radial direction perpendicular to the flexible annular disk device axis of rotation.

24. The apparatus of claim 9 wherein at least one measurement device is attached to the workpiece substrate carrier frame wherein the at least one measurement device measures the distance between the workpiece substrate carrier frame and the workpiece carrier plate when a 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 where the 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 the controlled and limited vertical movement distance of the floating circular rotatable workpiece carrier plate relative to the rotatable drive housing.

25. 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 hollow rotatable carrier drive shaft that has a vertical rotatable carrier drive shaft axis of rotation;

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

c) providing a rotatable flexible annular disk device having an annular disk device annular surface, an annular disk device outer periphery portion, an annular disk device inner periphery portion and an axis of rotation that is nominally located at the radial center of the annular disk device annular surface and that is nominally perpendicular to the annular disk device annular surface wherein the annular disk device outer annular periphery portion is moveable relative to the annular disk 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 that is nominally-perpendicular to the workpiece carrier plate flat bottom surface and a workpiece carrier plate nominally-vertical outer periphery annular surface located between the workpiece carrier plate top and bottom surfaces and wherein the floating circular rotatable workpiece carrier plate is movable relative to the rotatable drive housing;

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

f) providing a rotary workpiece drive that is connected with both the rotatable drive housing and the workpiece carrier plate wherein the rotary workpiece drive allowing 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 causes the workpiece carrier plate to be rotated by the rotatable drive housing;

g) providing at least two rotatable idlers having rotation axes wherein the rotatable idlers have outer periphery cylindrical or spherical surfaces that are rotatable about the rotatable idlers rotation axes;

h) attaching the at least two rotatable idlers to the movable workpiece substrate carrier frame wherein the at least two rotatable idlers'"'"' rotation axes are nominally parallel to the vertical rotatable carrier drive shaft axis of rotation and wherein the at least two respective rotatable idler'"'"'s outer periphery cylindrical or spherical surfaces are in contact with the floating circular workpiece carrier plate outer periphery annular surface, wherein the at least two rotatable idlers maintain the floating circular workpiece carrier plate rotation axis is nominally concentric with the carrier drive shaft axis of rotation;

i) moving that the floating circular workpiece carrier plate relative to the movable workpiece substrate carrier frame in a nominally-vertical direction along the floating circular workpiece carrier plate rotation axis wherein the at least two respective rotatable idler'"'"'s outer periphery cylindrical surfaces slide in vertical sliding contact with the floating circular workpiece carrier plate outer periphery annular surface and wherein the at least two rotatable idlers rotate as they are in contact with a rotating rotatable workpiece carrier plate;

j) attaching at least one workpiece having opposed workpiece top and bottom surfaces to the workpiece carrier plate flat bottom surface; and

k) providing a rotatable abrading platen having a flat abrasive coated abrading surface that is nominally horizontal;

l) 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 that is 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 annular disk device pressure chamber wherein the at least one workpiece bottom surface is positioned in flat-surfaced abrading contact with the rotatable abrading platen abrading surface to abrade the workpiece.