JPH10296622A - Polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the whole face of an upper surface plate always press a workpiece on a lower surface plate by making the upper surface plate follow the inclination of the lower surface plate when the lower surface plate is inclined by reducing the resistance against the vertical displacement of the rotating upper surface plate in a polishing device which polishes both faces of a work held between the upper and lower surface plates. SOLUTION: This device is provided with an upper surface plate 10, which is slidably and rotatably hung and supported on a support shaft through a universal joint mechanism, a lower surface plate on which workpieces to be polished are carried, a rotary main spindle, which plays a role of a rotary shaft of the upper surface plate and/or lower surface plate and connection mechanisms 21, 22, 23 and 24 for transmitting the torque of this rotary main spindle. In this case, in addition to the connection mechanisms, rotation transmitting means 23, 27 and 30, which transmit the torque and can displace in the axial direction of the rotary main spindle while transmitting the torque without resistance actually, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus, and more particularly to a polishing apparatus for polishing both sides of a thin plate.

[0002]

2. Description of the Related Art Disc-shaped members such as semiconductor wafers and magnetic disks are polished to a predetermined thickness by grinding or lapping, and mirror-finished by polishing. As a surface polishing apparatus for such lapping or polishing processing, a double-side polishing apparatus for simultaneously polishing both surfaces while supplying a polishing slurry with a disk-shaped work sandwiched between upper and lower platens is used.

FIG. 8 is a configuration diagram of such a double-side polishing apparatus. The main motor 2 is installed in the main body case 1,
It is connected to a rotating main shaft 20 via a V-belt 3 and a speed reducer 4. A gear mechanism 5 is mounted on the rotating main shaft 20, and is connected to a sun gear and an internal gear of an upper and lower platen and a planetary mechanism, respectively, which will be described later, and drives each part independently at a predetermined rotation speed. In other words, the rotating spindle 20 is formed by assembling four rotating drive shafts of the upper and lower platens and the sun gear and the internal gear of the planetary mechanism, which rotate independently of each other, having the same axis.

A lower platen 6 is rotatably mounted on the upper surface of the main body case 1, and a carrier 7 composed of a plurality of planetary gears is mounted thereon. Each carrier 7 holds a plurality of wafers (not shown) to be polished. A sun gear 8 and an internal gear 9 for causing the carrier 7 to perform a planetary motion are mounted on the central portion and the outer peripheral portion of the lower surface plate 6, respectively. An upper surface plate 10 is provided above the lower surface plate 6 so as to be able to move up and down with respect to the lower surface plate 6.

A driver 11 for transmitting the driving force from the main motor 2 to the upper surface plate 10 is mounted above the sun gear 8. As shown in FIG. 9, the driver 11 has a cylindrical shape, and has a plurality of grooves 11a formed in an axial direction on an outer periphery thereof. A driver hook 12 is hinged on the upper surface plate 10. The upper platen 10 is lowered, and the driver 11 is made to protrude from the center hole 10a of the upper platen 10, and the driver hook 12 is tilted at an appropriate rotation position to be engaged in the groove 11a of the driver 11.
Thereby, the rotation of the driver 11 is transmitted to the upper surface plate 10 side.

In FIG. 8, only one driver hook 12 is shown. In FIG. 9, parts other than the main parts are omitted to clarify the configurations of the driver 11 and the driver hook 12.

A driver 11 for rotating the upper platen 10, a sun gear 8 and an internal gear 9 for rotating the carrier 7 in a planetary rotation, and a lower platen 6.
Are independently driven at a predetermined number of revolutions via a gear mechanism 5 by the rotational driving force of the main motor 2.

The upper platen 10 is suspended from a support frame (not shown) provided inside the slurry supply powder ring 13, and the polishing slurry is supplied through a plurality of slurry supply pipes 14. . The support frame member is rotatably suspended and supported on a support shaft 16 via a universal joint 15. The universal joint 15 has a known universal joint structure such as a gimbal structure that rotatably supports two orthogonal axes and swings in all directions, and a joystick-type ball joint structure that holds a ball joint. It consists of. The upper surface plate 10 swingably supported by the support shaft 16 is moved up and down by a main cylinder 18 mounted on a cylinder arm 17. A sub-cylinder 19 for adjusting the pressing force is provided at the lower end of the main cylinder 18. During polishing, the upper platen is lowered by the main cylinder 18 and mounted on the lower platen 6, and the carrier 7 is pressed by its own weight. When adjusting this pressing force,
A load is applied to the upper platen 10 upward or downward by the sub-cylinder 19 to reduce or increase the pressing force.

In the double-side polishing apparatus having the above-described configuration, the rotational driving force from the main motor 2 is transmitted to the upper platen 10 via a connecting mechanism including a driver 11 and a driver hook 12. That is, when the driver hook 12 is engaged in the groove 11a of the driver 11 and the driver 11 rotates, the side surface of the groove 11a presses the side surface of the driver hook 12 in the rotating direction to rotate the driver hook 12, thereby making the upper setting. The board 10 rotates together with the driver 11.

Usually, in order to enhance the polishing efficiency, the upper platen 10
And the lower platen 6 are rotated in mutually opposite directions. In this case, in order to uniformly polish the entire surface with a constant polishing pressure, the upper platen 10 must always maintain the parallelism of the polished surface with the lower platen 6. For this reason, conventionally, the upper surface plate 10 is
The lower platen 6 is tiltably supported during swinging, so that even when the lower platen 6 is tilted during polishing, the upper platen is tilted to follow this, and the parallelism is always kept constant with the lower platen. ,
The entire polishing surface of the upper platen was intended to press the lower platen side with a constant pressing force.

[0011]

However, in the conventional double-side polishing apparatus, the rotational force is transmitted to the press-contact surface between the driver and the driver hook of the connecting mechanism for transmitting the rotational force from the main shaft to the upper surface plate. Is applied, the frictional force at the contact surface becomes very large, and it is almost impossible to slide each other up and down during rotation. For this reason, the sensitivity of the pressing force adjustment is extremely low, and when the lower platen rotates inclining, the pressing force eccentric with each rotation acts on the upper platen periodically.

This will be further described below. For the driver hook 12 shown in FIG. 9, the frictional resistance F per hook is represented by F = (１ ／) μ′μQ (R / r).

Here, μ ′ is a friction coefficient of the press contact surface of the rotation transmitting surface, μ is a friction coefficient between the carrier and the upper surface plate, Q is a vertical load which is a sum of a weight of the upper surface plate and a pressurized load, R is the radius of friction acting on the surface plate, and r is the radius of the pressing force acting position of the driver.

As an example, μ ′ = 0.2, μ = 1, Q = 10
Assuming that 0N, R = 110 mm, and r = 45 mm, the frictional resistance F per hook is 49 N, and 98 N for both hooks. That is, even when a vertical load of 100N is applied, 95% or more of 98N is consumed for frictional resistance. For this reason, even if a load for adjusting the pressure is further applied to the set upper platen during rotation, the force acting on the work is 5% or less thereof, and the pressure sensitivity is remarkably reduced due to the stick-slip phenomenon. .

When the lower stool is inclined, an eccentric push-up reaction force acts on the upper stool every rotation. The push-up reaction force is a force of 95% or more of the frictional resistance per one hook. Acts repeatedly as an eccentric load on the upper platen.
For this reason, the polishing uniformity is reduced, the polishing accuracy is reduced, and the eccentric load acts on the lower surface plate and the upper surface plate, so that the flatness is accelerated.

The present invention has been made in view of the above-mentioned drawbacks of the prior art. In a double-side polishing apparatus for polishing a work by sandwiching a work between upper and lower platens, a vertical displacement of the upper platen during rotation is provided. To provide a double-side polishing machine that lowers the resistance of the upper platen so that the entire surface of the upper platen can always press the work with a constant force against the lower platen when the lower platen is inclined, etc. With the goal.

[0017]

In order to achieve the above object, according to the present invention, there is provided an upper surface plate which is swingably and rotatably suspended on a support shaft via a universal joint mechanism, and a work to be polished. In a polishing apparatus comprising: a lower platen to be mounted; a rotary spindle serving as a rotation axis of the upper platen and / or the lower platen; and a coupling mechanism for transmitting a rotational force of the rotary spindle to the upper platen. A polishing apparatus which, in addition to the coupling mechanism, further comprises a rotation transmitting means capable of transmitting the rotational force and displaceable in the axial direction of the rotary spindle (with practically no resistance) during the transmission of the rotational force. I will provide a.

In this configuration, the coupling mechanism for transmitting the rotational force from the rotating main shaft to the upper surface plate, and separately transmitting the rotating force, is displaced in the axial direction of the main shaft with practically no resistance. A rotation transmitting means for significantly reducing the resistance of the upper stool to vertical displacement is provided. For this reason, the upper platen does not move up and down in the coupling mechanism by the pressing force on the coupling mechanism, but transmits only the rotational force, and applies a load to the upper platen from above and below to adjust the pressing force. In the case of displacing, the upper platen is displaced up and down by the displacement of the rotation transmitting means in the up and down direction while the position of the coupling mechanism portion is kept as it is. In addition, the force on the upper platen side due to the inclination of the lower platen and the like is absorbed by the rotation transmitting means being displaced in the axial direction (vertical direction) of the main shaft,
The upper platen always rotates following the inclination of the lower platen.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment,
The rotation transmitting means includes a driving member connected to the rotating spindle and rotating with the rotating spindle, a driven member fixed to the upper platen, a pulling side of the driving member during rotation and the driven member. It is characterized by comprising a leaf spring provided between members.

In this configuration, the upper platen is rotated by being pulled by a driving member on the main shaft side via a leaf spring. Therefore, when a vertical force acts on the upper surface plate, the leaf spring bends in the axial direction (vertical direction) of the main shaft while pulling the upper surface plate, and the connection with the upper surface plate responds to the vertical force. As a result, the upper platen can be displaced in the up-down direction to release this force.

In another preferred embodiment, the rotation transmitting means includes a driving member connected to the rotation spindle and rotating with the rotation spindle, a driven member fixed to the upper platen, and a rotation member. And a wire provided between the driven member and the driven member.

In this configuration, the upper surface plate is rotated by being pulled by the driving member on the main shaft side via the wire. Therefore, as in the case of the above-mentioned leaf spring, when a vertical force is applied to the upper surface plate, the wire moves in the axial direction (vertical direction) of the main shaft while pulling the upper surface plate, and moves the upper surface plate in the vertical direction. To dissipate this force.

In still another preferred embodiment, the rotation transmitting means comprises a bearing provided at a press-contact position for applying a rotational force by pressing an upper surface of the coupling mechanism.

In this configuration, the rotational force from the main shaft side is transmitted by pressing the upper platen through the coupling mechanism, and a bearing is provided at the transmission point of the pressing force, and the bearing rotates. The pressure contact surfaces at the point where the torque is transmitted are displaced up and down with respect to each other. Accordingly, when a vertical force acts on the upper surface plate during rotation, the press contact surfaces of the coupling mechanism portions are mutually displaced to escape this force and displace the upper surface plate in the vertical direction.

[0025]

FIG. 1 is a plan view of a rotation transmitting mechanism portion of an upper platen of a double-side polishing apparatus according to the present invention, and FIGS. 2 and 3 are cross-sectional views of AA and BB thereof. is there. FIG. 4
Is a plan view of the planetary mechanism.

A driving member for transmitting a rotational force to the upper platen 10 side to a rotary main shaft 20 composed of a coaxial set of rotary shafts (not shown) of four rotary members (upper and lower platens, sun gears, and internal gears). 21 is mounted. The driving member 21 has concave portions 22 at a plurality of positions (two positions in this example) on the outer peripheral edge thereof. A driven member 23 is provided on the outer periphery of the driving member 21. The driven member 23 is provided with the concave portion 22 of the driving member 21.
It has a convex portion 24 fitted into the inside. Thereby, the spindle 2
When 0 rotates and the driving member 21 rotates in the direction of the arrow P,
The inner wall of the concave portion 22 presses against and presses the side surface of the convex portion 24 of the driven member 23 to rotate the driven member 23 in the same direction (the state shown in the drawing).

The driven member 23 has a plurality of (four in this example) protruding pieces 23a around the driven member 23, and each protruding piece 2a.
At the tip of 3a, a bolt 2 is inserted via a spacer 25 (FIG. 2).
6, the ring-shaped leaf spring 27 is mounted. The upper platen 10 and the support arm 30 are connected to the leaf spring 27 at an intermediate position between the bolts 26 by bolts 29 via spacers 28 (FIG. 3). The four support arms 30 are integrated at a central portion, and a sleeve 31 is fixed on an upper portion thereof, and is mounted around the main shaft 20.

Thus, as described above, the driven member 23
Rotates in the direction of arrow P, the protruding piece 23a rotates in the same direction, and rotates the upper stool 10 connected thereto via a leaf spring 27 fixed to the end thereof. In this case, the leaf spring 27 and the projecting piece 23a and the bolt 29 are rotated so that the projecting piece 23a pulls and rotates the bolt 29 of the upper surface plate 10.
It is stretched between. That is, the leaf spring 27 that contributes to the transmission of the rotational force is substantially a portion on the tension side (the rear side in the rotational direction) of each protruding piece 23a and the front side of the bolt 29 behind the same. In this case, the leaf spring 27 on the rear side of the bolt 29 (front side of the protruding piece 23a) applies each bolt 29 to the front and rear protruding pieces 23.
It has a positioning function for holding it at an intermediate position of a.
This prevents the bolt 29 from rotating forward with inertia together with the support arm 30 and the upper stool 10 when the rotation is stopped or the like, thereby preventing the leaf spring 27 from being damaged.

The support arm 30 is bolted to the upper platen 10 with bolts 29.
The support disk 32 is mounted in a sleeve 31 integrally fixed to the center of the support arm 30. The supporting disk 32 is swingably supported on a hemispherical projection 34 at the center thereof. The hemispheric projection 34 is fixed to the upper end surface of the sub cylinder 33. The sub-cylinder 33 can be moved up and down to adjust the pressing force of the upper stool 10, and the support disk 32 is displaced in the up-down direction by moving the hemispheric projection 34 on the upper end surface up and down.

The support arm 30 is suspended from the support disk 32 via three wires 35, and the upper platen 10 is suspended. The semi-circular projection 34 on the upper end surface of the sub cylinder 33 and the wire 35 between the support disk 32 and the support arm 30 constitute a universal joint mechanism of the upper stool 10, which swingably supports the upper stool 10. I do. The sub-cylinder 33 is driven up and down by a main cylinder (not shown) to move the upper platen 10 up and down together with the hemispherical projection 34 and the support disk 32.

When the upper surface plate 10 is displaced in the vertical direction during rotation of the upper surface plate 10 by the vertical operation of the sub cylinder 33,
Since the pressing force for transmitting the rotational force from the driving member 21 on the main shaft side to the driven member 23 is large, the press contact surface is unlikely to be displaced in the vertical direction. Therefore, the projecting piece 23a of the driven member 23
The vertical position of the leaf spring 27 at the portion fixed by the bolt 26 is hard to be displaced. However, since the leaf spring 27 is easily bent and displaced in the vertical direction, the upper platen 1
The leaf spring 27 of the portion fixed to 0 by the bolt 29 is easily displaced in the vertical direction. Therefore, in order to adjust the pressing force during rotation, the upper platen 10 can be displaced vertically with a small resistance.

As described above, the carrier 7 for holding the work (not shown) to be polished is provided between the upper surface plate 10 and the lower surface plate 6 which are swingably supported by the support shaft via the universal joint mechanism. Is done. As shown in FIG. 4, a plurality of the carriers 7 are mounted between the sun gear 8 and the internal gear 9, and revolve with the rotation and make a planetary motion. Each carrier 7
Has a plurality of holes 7a and accommodates a thin plate-shaped work.

FIG. 5 shows a state in which the lower platen 6 is inclined in the double-side polishing apparatus having the above-described configuration. That is, lower platen 6
This shows a state where one side (right side in the figure) is slightly raised as indicated by an arrow R, and the other side (left side in the figure) is slightly lowered as indicated by an arrow S. In this state, the lower stool 6 is tilted, so that the upper stool 10 is tilted in accordance with the tilt, and the sun gear 8 and the internal gear 9 whose positions in the vertical direction are fixed are located between the upper and lower stools 6, 10. Carrier 7 sandwiched
However, it rises somewhat on the right side of the figure and falls somewhat on the left side of the figure. In this case, since the leaf spring 27 is bent and displaced in the axial direction as described above, the upper surface plate of the protruding piece 23a of the driven member 23 in FIG. The vertical position of the ten bolts 29 is displaced. That is, as shown in FIG. 5, the vertical distance between the leaf spring 27 of the bolt 29 and the driven member 23 is substantially the same as that of the driven member 23 which is hardly displaced in the vertical direction due to the rotational pressure. It is large on the right (G1) and small on the left (G2).

Further, since the support arm 30 fixed integrally with the bolt 29 is suspended from the support disk 32 via the wire 35, the support arm 30 is generated by the inclination of the upper platen 10. Driven member 2 in horizontal direction
The support arm 30 can be displaced with a slight resistance when the support arm 30 rotates counterclockwise in FIG. Thus, while the support disk 32 is kept horizontal, the sleeve 31 integrated with the support arm 30 is inclined,
The gap between 1 and the support disk 32 is small on the right side (G3) in the figure and large on the left side (G4) in the figure. In this manner, the upper surface plate 1 fixed integrally with the support arm 30
0 can be inclined following the inclination of the lower platen 6.

FIG. 6 shows another example of the universal joint mechanism of the double-side polishing apparatus according to the present invention. In this example, a support arm 30 that supports the upper platen 10 via a leaf spring 27 similar to that described above is used.
A rotation support shaft 37 is mounted on the center of the shaft via a bearing 36, and the first ball joint 3 is mounted above the rotation support shaft 37.
The two universal joints 8 and the second ball joint 39 are mounted via a shaft 40. The upper second ball joint 39 is connected to the support shaft 41 on the upper side. The support shaft 41 is connected to a main cylinder (not shown) and a sub-cylinder (not shown). The upper platen 10 is moved up and down by the main cylinder to set the upper platen and finely moved up and down by the sub-cylinder. To adjust the pressing force.

FIG. 6 shows a state in which the lower platen 6 is inclined. As in the case of FIG. 5, the upper platen 10 on the right side of the figure is lifted upward as indicated by the arrow R, and the upper platen on the left side of the figure. 10 is arrow S
As shown in FIG. In this case, similarly to the above-described embodiment, the leaf spring 2 follows the inclination of the lower platen 6.
7 is bent and the upper platen 10 is displaced in the vertical direction,
The support arm 30 is inclined, and a horizontal force acts on the upper end of the support arm 30 in an attempt to incline the central rotation support shaft 37.
Due to this horizontal force, the first ball joint 38 is displaced to the left in the drawing as shown by the arrow H to absorb this force. As a result, the upper second ball joint 39
Does not move horizontally and the axis 40 between the joints
The upper surface plate 10 can follow the inclination of the lower surface plate 6 and tilt without the support shaft 41 tilting. The other configuration and operation and effect are the same as those of the above-described embodiment.

FIG. 7 is a block diagram of another embodiment of the rotation transmitting mechanism of the double-side polishing apparatus according to the present invention. This example uses a wire 4 instead of the leaf spring 27 in the embodiment of FIG.
2a and 42b are provided. That is, the rotational force is transmitted via the coupling mechanism including the concave portion 22 of the driving member 21 and the convex portion 24 of the driven member 23 as described above, and the front and rear sides of the respective projecting pieces 23a of the driven member 23 are respectively provided. The wires 42a and 42b are attached and connected to the front and rear support arms 30 and the bolts 29 for fixing the upper platen 10 to each other. As in the case of the above-described leaf spring, the wire 42 on the tension side (the rear side in the rotation direction P) of the projecting piece 23a is used.
b pulls the bolt 29 to rotate the upper platen 10. The wire 42a on the front side of the protruding piece 23a is for positioning and holding the bolt 29 connected thereto. By using such wires 42a and 42b, similarly to the above-mentioned leaf spring, while transmitting a rotational force, the wire is bent and the support arm 30 and the upper platen 10 can be displaced in the vertical direction. Other configurations and operational effects are the same as those of the embodiment of FIG.

As still another embodiment of the present invention, the driving member provided on the main shaft side and the driven member receiving the rotational force by engaging with the driving member without using the leaf spring or the wire of the above-described embodiment. A bearing may be provided at a pressure contact position where torque is transmitted between the bearings. Thus, when the driven member side is pressed from the driven member side to transmit the rotational force in the horizontal plane, the pressure contact surfaces can slide relative to each other by the bearing, so that even if a large load is applied to the pressure contact position, the pressure contact surface is slightly displaced. It can be displaced up and down with a small resistance. This allows the upper platen to be displaced in the up and down direction while transmitting torque.
Similarly to the above-described embodiment, the vertical displacement for adjusting the pressing force of the upper platen and the vertical displacement when the upper platen is inclined following the inclination of the lower platen become possible. In this case, since the bearing can be directly attached to the driven member, the driven member and the upper platen can be integrally fixed.

In each of the above embodiments, the coupling mechanism for transmitting the rotational force from the main shaft side to the upper platen side is such that the inner wall of the concave portion is formed by fitting the two concave portions 22 and the convex portions 24 to the side wall of the convex portion. However, the present invention is not limited to this, and is not limited to this. The connection mechanism by the engagement of the driver and the driver hook shown in FIG. The present invention is applicable to a coupling mechanism having a transmission structure.

[0040]

As described above, according to the present invention, in addition to the connecting mechanism for transmitting the rotational force from the rotary spindle to the upper platen, the rotational force is transmitted separately, for example, as a leaf spring or a wire. In addition, when the upper platen side of the connecting mechanism is difficult to move up and down due to the pressing force on the connecting mechanism, only the rotational force is transmitted. The upper platen always rotates following the inclination of the lower platen due to the force on the upper platen side due to the inclination, etc., because the rotation transmission means such as a leaf spring or wire is easily displaced in the axial direction of the main shaft. Can be. Thereby, it is possible to obtain a predetermined polishing surface with high accuracy by vertically displacing the upper platen for adjusting the pressing force during the rotary polishing, and when the lower platen is inclined, Following this, the lower platen is constantly pressed with a constant load, and the work can be polished with a uniform force, so that a highly accurate, highly reliable and high quality polished surface can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of a double-side polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along the line BB of FIG. 1;

FIG. 4 is a plan view of the planetary mechanism of the embodiment of FIG. 1;

FIG. 5 is a cross-sectional view of the embodiment of FIG.
Sectional drawing of B part.

FIG. 6 is a configuration diagram of another example of the universal joint mechanism of the present invention.

FIG. 7 is a plan view of a main part of another embodiment of the present invention.

FIG. 8 is an overall configuration diagram of a double-side polishing apparatus.

FIG. 9 is a perspective view of a driver mechanism portion of the double-side polishing apparatus of FIG. 8;

[Explanation of symbols]

6: Lower surface plate, 7: Carrier, 8: Sun gear, 9: Internal gear, 10: Upper surface plate, 11: Driver, 12:
Driver hook, 13: powder ring, 15: universal joint mechanism, 16: support shaft, 18: main cylinder, 1
9: sub-cylinder, 20: rotating main shaft, 21: driving member, 22: concave portion, 23: driven member, 24: convex portion, 2
5: spacer, 26: bolt, 27: leaf spring, 28: spacer, 29: bolt, 30: support arm, 31: sleeve, 32: support disk, 33: sub cylinder, 34:
Hemisphere projection, 35: wire, 38: first ball joint, 39: second ball joint, 42a, 42b: wire.

Claims (4)

[Claims] 1. An upper platen supported by a support shaft via a universal joint mechanism so as to be swingable and rotatable, a lower platen on which a workpiece to be polished is mounted, and the upper platen and / or the lower platen. A polishing apparatus comprising: a rotating spindle serving as a rotating shaft of; and a coupling mechanism for transmitting the rotating force of the rotating spindle to the upper platen. In addition to the coupling mechanism, the polishing apparatus transmits the rotating force and rotates. A polishing apparatus comprising: a rotation transmitting means capable of displacing with a slight resistance in the axial direction of the rotating main shaft during the transmission of force. 2. A driving member connected to the rotating spindle and rotating with the rotating spindle, a driven member fixed to the upper platen, and a pulling force of the driving member during rotation. The polishing apparatus according to claim 1, comprising a leaf spring provided between the driven member and the driven member. 3. A drive member connected to the rotary spindle and rotating with the rotary spindle, a driven member fixed to the upper platen, and a pull of the drive member during rotation. The polishing apparatus according to claim 1, comprising a wire provided between the driven member and the driven member. 4. The polishing apparatus according to claim 1, wherein said rotation transmitting means comprises a bearing provided at a press-contact position for applying a rotational force by pressing an upper surface of said coupling mechanism.