Spider arm driven flexible chamber abrading workholder

• US 8,998,678 B2
• Filed: 01/07/2014
• Issued: 04/07/2015
• Est. Priority Date: 10/29/2012
• Status: Active Grant

• Current Assignee: Wayne O. Duescher
• Original Assignee: Wayne O. Duescher
• Inventors: Duescher, Wayne O.
• Primary Examiner(s): NGUYEN, GEORGE BINH MINH
• Application Number:
  US14/148,729
• Publication Number:
  US 20140120806A1
• Time in Patent Office: 455 Days
• Field of Search: 451/28, 451/41, 451285-290, 451/397, 451/398
• US Class Current: 451/28
• CPC Class Codes: B24B 37/32 Retaining rings
• CPC Class Codes: B24B 41/04 Headstocks; Working-spindles; Features relating thereto
• CPC Class Codes: B24B 49/16 taking regard of the load
• CPC Class Codes: B24B 7/04 involving a rotary work-table

Abstract

Flat-surfaced workpieces such as semiconductor wafers or sapphire disks are attached to a rotatable floating workpiece holder carrier that is supported by a pressurized-air flexible elastomer sealed air-chamber device and is rotationally driven by a circular flexible-arm device. The rotating wafer carrier rotor is 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. The range of abrading pressures is large and the device can provide a wide range of torque to rotate the workholder. Vacuum can also be applied to the elastomer chamber to quickly move the wafer away from the abrading surface. Internal constraints limit the axial and lateral 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 that has a vertical rotatable carrier drive shaft axis of rotation;

b) 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) a rotatable flexible annular elastomeric tube device having an axial length, an annular top surface, an annular bottom surface and an axis of rotation that extends along the axial length wherein the elastomeric tube device annular bottom surface is moveable relative to the elastomeric tube device annular top surface;

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 that is nominally-perpendicular to the workpiece carrier plate flat bottom surface and a workpiece carrier plate outer periphery annular surface located between the workpiece carrier plate top and bottom surfaces;

e) wherein the rotatable annular elastomeric tube device annular top surface is attached to the rotatable drive housing and the elastomeric tube device annular bottom surface is attached to the workpiece carrier plate top surface wherein the elastomeric tube device axis of rotation is nominally-coincident with the vertical rotatable carrier drive shaft axis of rotation;

f) 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, wherein the 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 the center of the nominally-circular flexible support element;

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

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

i) wherein the at least two rotatable idlers are attached to the movable workpiece substrate carrier frame wherein the at least two respective rotatable idler'"'"'s outer periphery cylindrical 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 to be nominally concentric with the carrier drive shaft axis of rotation;

j) wherein the floating circular workpiece carrier plate is moveable 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;

k) wherein at least one workpiece having opposed workpiece top and bottom surfaces is attached to the workpiece carrier plate flat bottom surface;

l) a rotatable abrading platen having a flat abrasive coated abrading surface that is nominally horizontal.

2. The apparatus of claim 1 where the elastomeric tube device annular top surface that is attached to the rotatable drive housing and the elastomeric tube device annular bottom surface that is attached to the workpiece carrier plate top surface form a sealed enclosed elastomeric tube-device pressure chamber having an internal volume contained by the elastomeric tube-device, the rotatable drive housing and the workpiece carrier plate top surface.

3. The apparatus of claim 2 wherein controlled-pressure air or controlled-pressure fluid or controlled-pressure vacuum is accessible into the sealed enclosed elastomeric tube device pressure chamber through an air, fluid or vacuum passageway connecting an air, fluid or vacuum passageway in the hollow rotatable carrier drive shaft to the enclosed elastomeric tube device pressure chamber and wherein the pressure or vacuum present in the enclosed elastomeric tube device pressure chamber can move the workpiece carrier plate vertically.

4. The apparatus of claim 3 wherein on the workpiece carrier plate top surface is configured so that controlled vacuum applied to the sealed enclosed elastomeric tube 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 compressing the rotatable elastomeric tube device in a direction along the elastomeric tube device axis of rotation wherein the workpiece carrier plate is moved vertically away from the rotatable abrading platen abrading surface.

5. The apparatus of claim 1 wherein the flexible annular elastomeric tube device is constructed from or mold-formed from impervious flexible materials comprising silicone rubber, room temperature vulcanizing (RTV) 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 of these materials and sheets of these materials.

6. The apparatus of claim 5 wherein the flexible annular elastomeric tube device is a bellows-type annular-pleated elastomeric tube.

7. The apparatus of claim 6 wherein the flexible annular elastomeric tube device is reinforced with rigid or semi-rigid annular hoop devices that are attached to selected individual annular-pleated portions of the bellows-type annular-pleated elastomeric tube.

8. The apparatus of claim 1 wherein the flexible support element at least one individual flexible arm distal end has a flexing joint where the distal end extends distally when a force is applied nominally-perpendicular to the flexible support element nominally-vertical rotatable flexible support element rotation axis.

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 wherein 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 is controlled and limited by contacting of the rotatable drive housing vertical excursion-stop device with the floating circular rotatable workpiece carrier plate vertical excursion-stop device and by contacting 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 which supplies vacuum or pressurized fluid to a hollow carrier drive shaft fluid passageway that is 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.

11. The apparatus of claim 3 wherein a rotatable stationary vacuum, air or fluid rotary union supplies pressurized fluid or vacuum to a hollow carrier drive shaft fluid passageway in the hollow carrier drive shaft that is routed to the sealed elastomeric tube device pressure chamber.

12. A process for the apparatus of claim 10 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.

13. A process for the apparatus of claim 11 wherein pressurized fluid is supplied to the sealed elastomeric tube device pressure chamber and wherein the applied pressure acts on the workpiece carrier plate top surface which creates 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 flat-surfaced abrading contact with the rotatable abrading platen abrading surface.

14. A process for the apparatus of claim 3 wherein vacuum is applied to the sealed enclosed elastomeric tube device pressure chamber wherein the vacuum generates a vacuum lifting force on the workpiece carrier plate wherein the vacuum lifting force forces the workpiece carrier plate top surface in rigid contact against a rotatable drive housing vertical excursion-stop device that is attached to the rotatable drive housing and wherein the workpiece substrate carrier frame and the attached workpiece carrier spindle are moved vertically to a position wherein a workpiece that is attached to the workpiece carrier plate flat bottom surface is in abrading contact with the rotatable abrading platen abrading surface.

15. The apparatus of claim 3 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 portions of the workpiece carrier plate flat bottom surface can be distorted out-of-plane by the controlled-pressure air or controlled-pressure fluid or controlled-pressure vacuum present in the sealed enclosed elastomeric tube device pressure chamber which acts on the workpiece carrier plate top surface.

16. The apparatus of claim 15 wherein multiple rotatable elastomeric tube devices are positioned concentric with respect to each other to form independent annular or circular rotatable elastomeric tube devices'"'"' sealed enclosed elastomeric tube device pressure chambers wherein independent sealed enclosed elastomeric tube device pressure chambers are formed between adjacent sealed enclosed elastomeric tube device pressure chambers, wherein each independent sealed rotatable elastomeric tube device sealed enclosed pressure chamber has an independent controlled-pressure air or controlled-pressure fluid source to provide independent controlled-pressure air or controlled-pressure fluid pressures to the respective rotatable elastomeric tube device'"'"'s sealed enclosed pressure chambers, wherein the flexible workpiece carrier plate bottom surface can assume non-flat shapes at the location of each independent rotatable elastomeric tube device'"'"'s sealed enclosed pressure chamber and the respective rotatable elastomeric tube device'"'"'s sealed enclosed pressure chambers apply independently controlled abrading pressures to the portions of the at least one workpiece abraded surface that is positioned on the flexible workpiece carrier plate at the respective rotatable elastomeric tube 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.

17. The apparatus of claim 1 wherein the floating workpiece carrier plate outer diameter outer periphery surface has a spherical shape.

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

19. The apparatus of claim 4 wherein vacuum supplied to the sealed enclosed elastomeric tube 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 rapidly away from abrading contact with the rotatable abrading platen abrading surface.

20. 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 elastomeric tube device having an axial length, an annular top surface, an annular bottom surface and an axis of rotation that extends along the axial length wherein the elastomeric tube device annular bottom surface is moveable relative to the elastomeric tube device annular top surface;

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 outer periphery annular surface located between the workpiece carrier plate top and bottom surfaces;

e) attaching the rotatable annular elastomeric tube device annular top surface to the rotatable drive housing and attaching the elastomeric tube device annular bottom surface to the workpiece carrier plate top surface wherein the elastomeric tube device axis of rotation is nominally-coincident with the vertical rotatable carrier drive shaft axis of rotation;

f) providing 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, wherein the 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 the center of the nominally-circular flexible support element;

g) attaching the at least one rotatable nominally-circular flexible support element central support ring to the rotatable drive housing and attaching the at least one flexible support element distal end to the floating circular rotatable workpiece carrier plate wherein the at least one rotatable flexible support element rotation axis is coincident with the rotatable drive housing rotation axis, and wherein the at least one rotatable nominally-circular flexible support element is rotated by the rotatable drive housing to provide rotation of the workpiece carrier plate, and wherein 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;

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

i) attaching the at least two rotatable idlers to the movable workpiece substrate carrier frame wherein the at least two respective rotatable idler'"'"'s outer periphery cylindrical 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 to be nominally concentric with the carrier drive shaft axis of rotation;

j) providing that the floating circular workpiece carrier plate is moveable 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;

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

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

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 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 enclosed elastomeric tube 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.