US20100221987A1

US20100221987A1 - Double Side Polishing Machine

Info

Publication number: US20100221987A1
Application number: US12/223,064
Authority: US
Inventors: Toshio Nagashima
Original assignee: TSC Corp
Current assignee: TSC Corp
Priority date: 2006-03-24
Filing date: 2006-03-24
Publication date: 2010-09-02
Also published as: WO2007110896A1

Abstract

The present invention is to provide a double side polishing machine which can apply a load by the upper lapping plate uniformly to works and the deflection of the upper lapping plate is restrained, which comprises a rotatable lower lapping plate, a rotatable upper lapping plate and movable to the lower lapping plate by an elevation mechanism, carriers which are put between the lower lapping plate and the upper lapping plate and in which a plurality of works are mounted, and a rotation and revolution mechanism for rotating and revolving the carriers between the lower lapping plate and the upper lapping plate, wherein a supporting plate for upper lapping plate which suspends the upper lapping plate is connected to an upper portion of a coupling mechanism provided oscillatably on a vertically movable supporting rod of the elevation mechanism, and an oscillation fulcrum of the coupling mechanism is located at approximately same height to a polishing surface of the upper polishing plate.

Description

TECHNICAL FIELD

This invention relates to a double side polishing machine for polishing a work such as a semiconductor wafer and a photomask.

BACKGROUND ART

A double side polishing machine disclosed in JP 2002-120143 A is that an upper lapping plate is supported by a cylinder for suspending in which fluid is a supporting medium so that a processing load can be applied uniformly to a work, namely that a plurality of supporting mechanisms supporting the upper lapping plate with fluid as supporting medium are provided at specific intervals around a center axis line of the upper lapping plate between a suspender for the lapping plate mounted on an elevator for rising and falling the upper lapping plate and the upper lapping plate.
A polishing machine disclosed in JP 2002-154049 A is that a supporting disc whose size is similar to an upper lapping plate is provided on a front end of a rod of a cylinder device for elevating the upper lapping plate, and that deflection of the upper lapping plate is prevented by supporting between the supporting disc and the upper lapping plate by a plurality of supporting rods.
JP 2002-346918 A discloses a double side polishing machine which is provided with a lower lapping plate provided rotatably, an upper lapping plate provided above the lower lapping plate movably up and down and rotatably, a sun gear provided rotatably at a center position of the lower lapping plate, an internal gear provided rotatably at an outer peripheral side of the lower lapping plate, and carriers which can rotate and revolve with rotation of both gears by engaging with the sun gear and the internal gear and which can hold works, wherein an arm connected with a power source is provided above the upper lapping plate, a drive pin projecting outward in a radial direction is provided either on an outer peripheral end portion of the arm or on an outer peripheral end portion of the upper lapping plate, a drive bracket having a groove in which the drive pin is engaged with a specific clearance in a rotating direction is provided either on an outer peripheral end portion of the arm or on an outer peripheral end portion of the upper lapping plate, and a drive transmission mechanism for transmitting a drive force in the arm side to the upper lapping plate is constituted by the drive pin and the drive bracket. Besides, it discloses that the arm and the upper lapping plate are connected removably relatively by a suspended member.

SUMMARY OF THE INVENTION

As disclosed in the above mentioned references, it is a special problem in the double side polishing machine that a load by the upper lapping plate is applied uniformly to works and the deflection of the upper lapping plate is prevented. Furthermore, in recent years, because high accuracy for polishing is required, the above problem must be solved in the highest accuracy condition.
Besides, because a suspended position as an oscillation fulcrum of the upper lapping plate is at an end portion of the rod of the cylinder, distance between the upper lapping plate and the oscillation fulcrum is large and as a result, disadvantage such that variability of the upper lapping plate by variability of the rod is large is arisen.
Accordingly, the present invention is to provide a double side polishing machine in which load to works is applied equally by preventing variability and deflection of the upper lapping plate.
Therefore, the present invention is a double side polishing machine comprising a rotatable lower lapping plate, a rotatable upper lapping plate and movable to the lower lapping plate by an elevation mechanism, carriers which are put between the lower lapping plate and the upper lapping plate and in which a plurality of works are mounted, and a rotation and revolution mechanism for rotating and revolving the carriers between the lower lapping plate and the upper lapping plate, wherein a supporting plate for upper lapping plate which suspends the upper lapping plate is connected to an upper portion of a coupling mechanism provided oscillatably on a vertically movable supporting rod of the elevation mechanism, and an oscillation fulcrum of the coupling mechanism is located at approximately same height to a polishing surface of the upper polishing plate. Namely, the oscillation fulcrum is positioned on a standard plane expanding from the polishing surface of the upper polishing plate.
Thus, because the oscillation fulcrum of the upper lapping plate is located at approximately same height to the polishing surface thereof, distance between suspended positions of the upper polishing plate and the oscillation fulcrum can be made to a minimum, so that the variability of the upper polishing plate can be made to a minimum.
Besides, it is preferred that said upper polishing plate is suspended on the supporting plate outward in a radial direction from a center of gravity in one side of the polishing surface of the upper polishing plate. Thus, as the prior upper polishing plate is in a doughnut-shape, it has a tendency of warping so that the outer peripheral portion goes down, but because the upper polishing plate is supported outward from the center of polishing surface thereof, the outer peripheral portion thereof can be prevented going down and an inner peripheral portion thereof is difficult to go down, so that the deflection of the upper polishing plate can be prevented.
Furthermore, it is preferred that the supporting plate has a plurality of reinforcement ribs extending along the radiation direction. Thus, as strength of the supporting plate can be increased, the deflection of the upper lapping plate due to the deflection of the supporting plate can be prevented.
Moreover, it is preferred that the coupling mechanism is a gyro-mechanism and a center position of the gyro-mechanism is positioned at approximately same height to the polishing surface of the upper lapping plate. By this manner, load bias of the upper lapping plate due to a fine gap and an inclination of the supporting rod can be prevented.
Besides, it is preferred that the upper lapping plate can be rotatable by an upper lapping plate rotation mechanism for rotating the supporting rod and the upper lapping plate rotation mechanism is provided on the elevation mechanism. It has an effect such that a lower lapping plate rotation mechanism can be simplified by providing the upper lapping plate rotation mechanism separately from the lower lapping plate rotation mechanism. Thus, mechanical or structural resonance between the upper and the lower lapping plates can be prevented.
Due to the abovementioned constitution, according to the present invention, since an oscillation fulcrum of a coupling mechanism holding a support plate for upper lapping plate is positioned on an approximately same as a polishing surface of the upper lapping plate, distance between the polishing surface of the upper polishing plate and the oscillation fulcrum can be made to a minimum, so that an area of oscillation can be smaller and then polishing accuracy can be increased. Besides, positions suspending the upper polishing plate are positioned outward from a center of gravity in one side thereof and reinforcement ribs are formed on the supporting plate, so that deflection of the upper lapping plate can be prevented and load applied to works can be made uniformly and as a result, best accuracy double side polishing can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a double side polishing machine according to an embodiment of the present invention.

FIG. 2 is an enlarged diagram showing around upper and lower lapping plates of the double side polishing machine according to the embodiment of the present invention.

FIG. 3 is an enlarged diagram of the upper polishing plate of the double side polishing machine according to the embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention is explained by referring drawings.
A double side polishing machine 1 according to an embodiment of the present invention comprises an upper polishing plate 2 and a lower polishing plate 3 between which a plurality of carriers not shown in figures installing plural works are put, and a sun gear 4 and an internal gear 5 with which the carriers are engaged in order to rotate and revolve.
The lower polishing plate 3 is secured on a supporting plate for lower polishing plate 6 to be held and rotated via a rotatable cylindrical shaft 7 on which the supporting plate 6 is secured. A rotation shaft 8 passing though the rotatable cylindrical shaft 7 is provided inside the rotatable cylindrical shaft 7, a closed-end and cylindrical sun gear portion 9 is secured at a front end of the rotation shaft 8, and then the sun gear 4 formed on an outer peripheral surface of the sun gear portion 9 is rotated with rotation of the rotation shaft 8. Besides, a cylindrical holder portion 10 for receiving axial direction load applied on the rotatable cylindrical shaft 7 and for holding it rotatably is provided outside the rotatable cylindrical shaft 7. Further, a rotatable outer cylindrical portion 11 for driving the internal gear 5 is provided rotatably on an outer peripheral portion of the cylindrical holder portion 10, a peripheral wall portion for internal gear 12 extending to a radically outer peripheral of the rotatable outer cylindrical portion 11 is formed on the rotatable outer cylindrical portion 11, and the internal gear 5 is secured on an upper end inner peripheral edge of the peripheral wall 12.
Further, the rotatable outer cylindrical portion 11 is rotated via a gear mechanism 13 by a motor 14 and the rotatable cylindrical portion 7 is rotated via a coupling mechanism 16 such as belts by a motor 17. Besides, the rotation shaft 8 is rotated via a gear mechanism 18 by coupling with the rotatable cylindrical shaft 7.
The upper polishing plate 2 is movable up and down by means of the elevation mechanism 19. The elevation mechanism 19 comprises a first lift mechanism 20 for moving the upper polishing plate 2 along a large scale up and down, a second lift mechanism 21 for moving the upper polishing plate 2 along a small scale up and down and a supporting rod 30 for supporting the upper polishing plate 2, and further comprises a motor 22 and a gear mechanism 23 for rotating the supporting rod 30.
As shown in FIGS. 2 and 3, the upper polishing plate 2 is secured on a supporting plate for upper polishing plate 50 secured on a gyro-mechanism 40 via the gyro mechanism 40 provided on a front end of a cylindrical holding portion 31 in which the rotatable supporting rod 30 is fitted. Secured points S between the supporting plate 50 and the upper polishing plate 2 are set outward at a specific distance d away from a gravity point O in sectional view of one side in a radial direction of the upper polishing plate 2. Thus, though load is applied to the upper polishing plate 2 so that an inner peripheral edge portion goes down, this load is applied in a direction such that the inner peripheral edge portion of the upper polishing plate 2 is compressed, deflection of the upper polishing plate 2 can be prevented more than a case that load is applied to the outer peripheral edge portion.
Moreover, a plurality of reinforcement ribs 51 extending along the radical direction from a cylindrical portion 53 formed around a through hole 52 through which the supporting rod 30 passes are formed on the supporting plate 50. Thus, as it can be prevented that the supporting plate 50 is deflected by the load of the upper polishing plate 2, the deflection of the upper polishing plate 2 can be further prevented and the load applied to the works of the carriers can be applied uniformly.
The gyro-mechanism 40 is constituted of first axial rods 41 secured on the cylindrical holding portion 31, first rings 42 rotatable around the first axial rods 41, second axial rods not shown in figures which are secured on the first rings 42, second rings 43 rotatable around the second axial rods not shown in figures, third axial rods 44 secured on the second rings 43 and third rings 45 rotatable around the third axial rods 44, respectively, and the supporting plate 50 is secured at upper ends of the third rings 45. Furthermore, a cover plate 46 is provided at lower ends of the third rings 45. In this embodiment, the first rods 41, the second rods and the third rods 44 are arranged at an angle of 60° one another. Thus, as the supporting plate 50 and the upper polishing plate 2 can be moved in three dimensional direction to the supporting rod 30, a fine gap of the supporting rod 30 and the like can be absorbed, so that balancing of the upper polishing plate 2 to the lower polishing plate 3 can be maintained. Furthermore, each center axis of the first rod 41, the second rod and the third rod 44 is positioned at approximately same height to a polishing surface of the upper polishing plate 2. Namely, the oscillation fulcrum is positioned on a standard plane expanding from the polishing surface of the upper polishing plate 2.
Due to the abovementioned constitution, the carriers installing works are arranged so as to be engaged with the sun gear 4 and the internal gear 5, the upper polishing plate 2 is gone down to the lower polishing plate 3 so as to put the carriers between the upper and the lower polishing plates 2 and 3, and then, the upper polishing plate 2, the lower polishing plate 3, the sun gear 4 and the internal gear 5 are rotated in specific in a desired directions respectively, so that both sides of the works can be polished well. Besides, in this operation, because deflection of the upper polishing plate 2 is restrained remarkably, balancing of the upper polishing plate 2 can be held and load of the upper polishing plate can be applied to the works in the carriers uniformly, so that polishing accuracy of the works can be increased remarkably.

Claims

1. A double side polishing machine comprising a rotatable lower polishing plate, a rotatable upper polishing plate which goes up and down to said lower polishing plate by means of an elevation mechanism, carriers putting between said lower and said upper polishing plates and installing a plurality of works respectively and a rotation and revolution mechanism for rotating and revolving said carriers between said lower and said upper polishing plates,

wherein a supporting plate for upper polishing plate which suspends said upper polishing plate is connected to an upper portion of a coupling mechanism is provided oscillatably on vertically movable supporting rod of said elevation mechanism, and

wherein an oscillation fulcrum of said coupling mechanism is positioned at approximately same height to a polishing surface of said upper polishing plate.

2. A double side polishing machine according to claim 1, wherein said upper polishing plate is suspended on said supporting plate outward in a radial direction from a center of gravity in one side of said polishing surface of said upper polishing plate.

3. A double side polishing machine according to claim 1, wherein the supporting plate has a plurality of reinforcement ribs extending along the radiation direction.

4. A double side polishing machine according to claim 2, wherein the supporting plate has a plurality of reinforcement ribs extending along the radiation direction.

5. A double side polishing machine according to claim 1, wherein said coupling mechanism is a gyro-mechanism and a center position of said gyro-mechanism is positioned at approximately same height to said polishing surface of said upper lapping plate.

6. A double side polishing machine according to claim 2, wherein said coupling mechanism is a gyro-mechanism and a center position of said gyro-mechanism is positioned at approximately same height to said polishing surface of said upper lapping plate.

7. A double side polishing machine according to claim 3, wherein said coupling mechanism is a gyro-mechanism and a center position of said gyro-mechanism is positioned at approximately same height to said polishing surface of said upper lapping plate.

8. A double side polishing machine according to claim 4, wherein said coupling mechanism is a gyro-mechanism and a center position of said gyro-mechanism is positioned at approximately same height to said polishing surface of said upper lapping plate.

9. A double side polishing machine according to claim 1, wherein said upper lapping plate can be rotatable by an upper lapping plate rotation mechanism for rotating said supporting rod and said upper lapping plate rotation mechanism is provided on said elevation mechanism.

10. A double side polishing machine according to claim 2, wherein said upper lapping plate can be rotatable by an upper lapping plate rotation mechanism for rotating said supporting rod and said upper lapping plate rotation mechanism is provided on said elevation mechanism.

11. A double side polishing machine according to claim 3, wherein said upper lapping plate can be rotatable by an upper lapping plate rotation mechanism for rotating said supporting rod and said upper lapping plate rotation mechanism is provided on said elevation mechanism.

12. A double side polishing machine according to claim 4, wherein said upper lapping plate can be rotatable by an upper lapping plate rotation mechanism for rotating said supporting rod and said upper lapping plate rotation mechanism is provided on said elevation mechanism.

13. A double side polishing machine according to claim 5, wherein said upper lapping plate can be rotatable by an upper lapping plate rotation mechanism for rotating said supporting rod and said upper lapping plate rotation mechanism is provided on said elevation mechanism.

14. A double side polishing machine according to claim 6, wherein said upper lapping plate can be rotatable by an upper lapping plate rotation mechanism for rotating said supporting rod and said upper lapping plate rotation mechanism is provided on said elevation mechanism.

15. A double side polishing machine according to claim 7, wherein said upper lapping plate can be rotatable by an upper lapping plate rotation mechanism for rotating said supporting rod and said upper lapping plate rotation mechanism is provided on said elevation mechanism.

16. A double side polishing machine according to claim 8, wherein said upper lapping plate can be rotatable by an upper lapping plate rotation mechanism for rotating said supporting rod and said upper lapping plate rotation mechanism is provided on said elevation mechanism.