JPH0258059B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a double-sided polishing device suitable for processing both sides of extremely thin workpieces.

[Prior art] Conventionally known double-sided polishing devices such as lapping machines,
A plurality of carriers are meshed with a sun gear located at the center and an internal gear around the sun gear, and the sun gear and the internal gear are rotated to generate planetary motion in the carrier, so that the gear is held by the carrier. The workpiece is configured to be machined on both sides using upper and lower surface plates, but since a carrier that is thinner than the workpiece is required, a very thin carrier must be used when processing thin workpieces such as semiconductor wafers. It won't happen.

However, as the wall thickness of the carrier becomes thinner, its strength inevitably decreases, especially the strength of the teeth cut around it, making it more likely to break. There are many cases where this becomes difficult.

Additionally, in general, there is a dimensional difference of about 2.5 times between the inner diameter and outer diameter of the annular polished surface of a surface plate.
The difference in circumferential speed between the inside and outside was 2.5 times as high, and this prevented equal sliding contact between the surface plate and each workpiece, causing a reduction in polishing accuracy. Therefore, in order to improve polishing accuracy, it is necessary to minimize the influence of the difference in circumferential speed of the surface plate.

[Problems to be Solved by the Invention] An object of the present invention is to make it possible to reduce the thickness of the carrier by improving the structure and driving method of the carrier.
The object of the present invention is to provide a double-sided machining device that is capable of machining extremely thin workpieces and is less susceptible to the influence of the difference in circumferential speed between the outside and the outside of the surface plate.

[Means for Solving the Problems] In order to solve the above problems, the double-sided processing apparatus of the present invention includes a rotatable upper and lower surface plate for polishing the upper and lower surfaces of the workpiece, and a concentric surface plate around the surface plate. An internal gear is fixed to the machine body, and a support hole for the work is provided in the annular carrier body, which has a larger diameter than the surface plate. The carrier is constructed by installing a small number of ring-shaped gears and an inner ring on the inner periphery of the carrier body, and the ring-shaped gear partially meshes with the internal gear at a position away from the polished surface of the surface plate. The drive member is attached to the carrier drive shaft located at the center of the panel, is partially inscribed in the inner ring of the carrier, and rotates eccentrically to swing the carrier in the radial direction. .

[Operation] When the drive member inscribed in the inner ring of the carrier is eccentrically rotated by the carrier drive shaft, the carrier swings in the radial direction while changing the meshing position with the internal gear, and the ring gear and the inner ring rotate. It rotates at a low speed based on the difference in the number of teeth with the gear. Therefore, each workpiece held by the carrier rotates at a low speed around the drive shaft while repeatedly oscillating with the carrier, and moves up and down while drawing a combined trajectory of these oscillating motions and rotational motions. The surface plate allows both sides to be machined evenly over the entire surface, making it less susceptible to the difference in circumferential speed between the inside and outside of the surface plate.

[Effect] Since the carrier is formed by attaching separately formed ring gears and inner rings to the outer and inner peripheries of the carrier body, the strength of the outer and inner peripheries of the carrier, which are subjected to large forces during driving, is reduced to the strength of the carrier body. The carrier body can be made to be as thin as desired depending on the workpiece, so even extremely thin workpieces can be processed reliably. Furthermore, since the above-mentioned carrier is driven by the eccentric rotation of the drive member inscribed in the inner ring with the internal gear fixed, not only is there no need for the conventional sun gear, but the internal gear and There is no need to drive both sun gears to rotate the carrier, so the structure is very simple and damage to the carrier is less likely to occur, making it easier to reduce the thickness of the carrier. Since this method is used, loading and unloading of the carrier and workpiece is easy and has good workability.

In addition, by fixing the internal gear and eccentrically rotating the central drive shaft, the carrier can be rotated at a low speed based on the difference in the number of teeth with the internal gear while swinging in the radial direction. Prevents partial unevenness in workpiece machining speed due to the difference in circumferential speed inside and outside the surface plate that occurs when the carrier rotates at high speed.
It is possible to make each workpiece draw a trajectory that combines rocking motion and rotational motion, so that the entire surface of the workpiece can be brought into almost equal sliding contact with the surface plate, thereby eliminating the influence of the difference in circumferential speed of the surface plate. High polishing accuracy can be obtained. Furthermore, the sliding movement of the carrier in the radial direction can increase the sliding contact speed and trajectory length between the workpiece and the surface plate, so high-precision machining can be performed in a short time without the need to rotate the carrier at high speed. It can be carried out.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings. In FIG. An annular lower surface plate and an upper surface plate are shown, and the lower surface plate 2 is
It is fixed on the surface plate support 4 with a pin 5, and the surface plate support 4
The upper surface plate 3 is connected to a drive source (not shown) via a lower surface plate drive shaft 6 fixed to the lower surface plate.
It is fixed to a support plate 7 with screws 8, and is connected to a drive source via a locking plate 9 that can be freely engaged and detached from the support plate 7 and a drive shaft 10 for the upper surface plate that is fixed to the locking plate 9. .

Further, around the surface plates 2 and 3, an internal gear 11 and an annular receiving plate 12 are located concentrically with the surface plates 2 and 3.
is fixedly attached to the upper end of a pedestal 13 fixed on the machine body 1, and a carrier 14 that meshes with the internal gear 11 is disposed on the lower surface plate 2.

As is clear from FIGS. 2 and 3, the carrier 14 has an annular carrier body 15 having a larger diameter than the surface plates 2 and 3 and having a plurality of workpiece support holes 16. A ring gear 17 having fewer teeth than the internal gear 11 is attached to the outer periphery of the carrier body 15 so as not to overlap with the polished surfaces of the surface plates 2 and 3, and a ring gear 17 is attached to the inner periphery of the carrier body 15, that is, the edge of the center hole 18. An inner ring 19 is attached so as not to overlap the polished surfaces of the surface plates 2 and 3, and the carrier 14 is supported by the receiving plate 12 while the ring gear 17 partially meshes with the internal gear 11. It is set on the lower surface plate 2 in a state where it is supported from below, and a workpiece 20 to be machined is fitted and supported in each workpiece support hole 16. At this time, the carrier 14
It will be eccentric by an eccentricity E with respect to the center.

In order to drive the carrier 14, the surface plates 2 and 3
The carrier drive shaft 21 located in the center of the
A disc-shaped drive member 22 is eccentrically fixed, and a roller 23 rotatably attached to the drive member 22 is inscribed in the inner ring 19.

In the double-side polishing apparatus of the present invention having the above configuration, when the carrier drive shaft 21 is rotated in the direction of the mismark A and the drive member 22 is eccentrically rotated, the carrier 14 changes its meshing position with the internal gear 11. The workpiece 20 held by the carrier 14 rotates in the direction of arrow B at a speed based on the difference in the number of teeth between the internal gear 11 and the ring gear 17. The points a, b, and c on each workpiece 20 rotate at low speed around the drive shaft 21 while swinging together, and as shown in FIG. The upper and lower surface plates 2 rotate in opposite directions while drawing
3, its upper and lower surfaces are processed.

In this case, in the carrier 14, the carrier body 15, the ring-shaped gear 17 and the inner ring 19, which are subjected to a large force during driving, are constructed as separate members.
It can be formed into a thin wall to suit the needs of the user, making it possible to process thin workpieces.

The eccentricity E and rotation speed N of the carrier 14 are as follows: Z ₁ : Number of teeth of internal gear Z ₀ : Number of teeth of ring gear M: Module n: Rotation speed of carrier drive shaft, E=1 /2(Z ₁ −Z ₀ )×M N=Z ₁ −Z ₀ /Z ₀ ×n.

As can be seen from the second equation above, the number of rotations of the carrier is smaller than the number of rotations of the carrier drive shaft 21, but the number of oscillations of the carrier is the same as the number of rotations of the carrier drive shaft. The polishing directions of the upper and lower surface plates 2 and 3, which rotate in opposite directions, are both circumferential with respect to the workpiece 20, but the carrier 14, that is, the workpiece 2
Since the oscillation of 0 is performed in the radial direction of the surface plates 2 and 3 within the range of 2E, very rational machining is performed. At the same time, it can be processed with high precision and high efficiency.

In addition, to take out the workpiece 20 that has been processed,
This can be done by raising the upper surface plate 3, and in this case, the internal gear 11 can be configured to be able to descend relative to the lower surface plate 2.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the main parts of the double-side polishing device according to the present invention, Fig. 2 is a cross-sectional view with the surface plate removed, Fig. 3 is a plan view thereof, and Fig. 4 is a cross-sectional view of a workpiece during machining. FIG. 2 is an explanatory diagram showing a locus drawn by each point. 2...Lower surface plate, 3...Upper surface plate, 11...Internal gear, 14...Carrier, 15...Carrier body,
16...Work support hole, 17...Ring gear,
19... Inner ring, 20... Workpiece, 21... Carrier drive shaft, 22... Drive member.

Claims (1)

[Scope of Claims] 1. A rotatable upper and lower surface plate for polishing the upper and lower surfaces of a workpiece; an internal gear arranged concentrically around the surface plate and fixed to the machine body; and the surface plate. A support hole for the workpiece is provided in an annular carrier body having a larger diameter, a ring-shaped gear with a smaller number of teeth than an internal gear is attached to the outer periphery of the carrier body, and an inner ring is attached to the inner periphery of the carrier body. The ring gear is attached to a carrier drive shaft located at the center of the surface plate, and the ring gear partially meshes with the internal gear at a position away from the polished surface of the surface plate. A double-sided polishing device comprising: a drive member that is partially inscribed in a ring and rotates eccentrically to swing the carrier in a radial direction.