JPS60197363A - Polishing of wafer and apparatus thereof - Google Patents

Abstract

PURPOSE:To permit the polishing with high precision and the discrimination for the front and back surfaces by revolving a holded wafer in horizontal plane and moving the upper and lower surface plates which hold the wafer in the vertical direction, in reciprocation in the lateral direction synchronously opposed at each different transfer speed. CONSTITUTION:A polished article 4 is fitted into each accommodation hole on a carrier 5 and loaded onto a lower surface plate 1, and an upper surface plate 7 is arranged so that the undersurface contacts with the uppersurface of the polished article 4, and an upper track 8 on the both sides is engaged with the reverse feed gears 3 and 3. A guide gear 6 is driven, pouring abrasive agent onto the both surfaces of the polished article 4, and the carrier is revolved at a prescribed speed in a certain direction. When the reverse feed gears 3 and 3 repeat the turning in reverse at a prescribed angle by the aid of a driving apparatus, the upper and lower surface plates 7 and 1 repeat the horizontal reciprocating movement in the opposite directions. Since the lateral reciprocating speed differs on the lower and the upper surface plates 1 and 7, the finished state of the upper and lower surfaces of the polished article 4 differs, and the discrimination for the front and back surfaces is facilitated, and each degree of flatness and parallelism can be improved with a certain sliding speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polishing method and apparatus for polishing both surfaces of a semiconductor wafer with high precision and in a manner that allows easy discrimination between the front and back surfaces.

In order to make it easier to distinguish between the front and back sides of semiconductor wafers, one side of the wafer is subjected to as-slicing, as-wrapping, or as-etching, and the other side is finished with gold. For example, a well-known polishing apparatus as shown in FIG. 1 may be used.

8g1 Diagram (A) shows the n9-ehaer 1 attached to the block 11.
2..., this wafer 12... is mounted, and the wafer 11 is placed on the polishing cloth 14 stretched on the surface plate 13 in FIG. 2(B). . #13 is not shown
The shaft is connected to the driving bone, and is rotated to the left about the vertical axis 0. Then, a holder 15 is placed over the block 11 to hold the block 11.

The holder 15 is connected to an elevating device (not shown) by a universal joint, and can be raised and lowered and rotated freely.

To perform polishing, while dropping a polishing liquid onto the surface plate 13, the surface plate 13 is rotated in the direction of the arrow in the figure by a swivel drive device (not shown). As a result, the holder 15 is rotated by itself in the direction of the arrow in the figure, and the lower surface of the wafer 12 is rubbed against the upper surface of the polishing cloth 14 and polished using the polishing liquid.

However, in such a polishing device, the wafer 12...
Since each of the 2 and 3 is polished in a trajectory with a constantly changing angular velocity, there was a problem that uniform polishing could not be achieved and it was difficult to obtain a high degree of flatness.

Friend, the work of attaching and detaching the wafers 12 in such a device requires the work of attaching and peeling the wafers 12 to the block 11, which is inefficient and takes a considerable amount of time. However, automation of this work has not become widespread due to restrictions such as the size and weight of the block 11.

Furthermore, as the diameter of the wafers 12 increases, the number of wafers that can be attached to the block 11 decreases, and in order to compensate for the decrease in efficiency, the horizontal rotation of the surface plate 3 is There was also the problem that the machining accuracy deteriorated due to unfavorable conditions.

This invention was made in view of the above-mentioned 11G circumstances, and it is possible to polish a wafer with high precision by applying a uniform surface pressure to the wafer and to make it easy to distinguish between the front and back sides, and also to polish the wafer in a manner that makes it easy to distinguish between the front and back sides. It is an object of the present invention to provide a wafer polishing method and apparatus that can cope with the increase in diameter.

The present invention will be explained below based on the drawings.

FIGS. 2(A) and 2(B) show an embodiment of the device of the present invention,
In the figure, a lower rack 2 is provided on the lower surface of the flat lower surface plate 1.
is fixed. The lower racks 2 are two rectangular members extending a predetermined length on both sides of the lower surface plate 1, and have teeth formed on their upper surfaces.

On this lower rack 2, the reversing feed gear 3.3 is placed on the lower surface plate 1.
0 and 6, respectively, and are held so as to be rotated by a drive device (not shown). Further, objects to be polished (wafers) 4 are placed on the upper surface of the lower surface plate 1, with the objects to be polished (wafers) 4 being loaded into the respective accommodation holes of the carrier 5.

This carrier 5 is disc-shaped and has teeth formed on its outer periphery. A plurality of guide gears 6 are provided around the outer periphery of the carrier 5, and are meshed with the carrier 5, and are connected to a drive device (not shown) to rotate and hold the carrier 5. There is. An upper surface plate 7 having the same shape as the lower surface plate 1 is slidably provided on the upper surface of the object 4 to be polished, which is placed on the lower surface plate 1. On the upper surface of this upper surface plate 7, an upper rack 8 opposite to the lower rack 2 fixed to the lower surface of the lower surface plate 1 described above is mounted, and is engaged with the upper end teeth of the anti-transfer and re-gear 3.3. .

By the way, in the reverse feed gears 3, 3, there is a gap between the lower end teeth 3a, 3a that mesh with the lower rack 2 side and the tooth teeth ab, 3b that mesh with the upper rank 8/1. After a while,
It can be said that the lower rack 2 and the upper rack 8 are linked to each other by gears having a predetermined gear ratio. Furthermore, a polishing cloth 9 is attached to the lower surface plate 1 and the upper surface plate 7.

In the nine-polishing apparatus configured as described above, first, the object to be polished 4 is
... is loaded into each accommodation hole of the carrier 5 and placed on the lower surface plate 1. Next, the upper surface plate 7 is installed so that its lower surface is in contact with the upper surface of the object to be polished 4 . Then, while injecting abrasive into both sides of the object to be polished 4, the guide gear 6 is driven, and the carrier 5t is
- Rotate in a fixed direction at a given speed. Furthermore, when the anti-transfer gear 3.3 repeats rotation in reverse at a predetermined angle by a drive device (not shown), the upper surface plate 7 and the lower surface plate 1 are Each repeats horizontal reciprocating motion in opposite directions. At that time, the lower end tooth 3a of the anti-transfer snipe 73.3,
3a and upper end tooth 3t), lower surface plate 1 at the ninth gear ratio of 3b.
The reciprocating speed of the upper surface plate 7 to the left and right is different. For this,
The lower surface plate 1 and the upper surface plate 7 perform the same polishing by constant rotation and sliding on both sides of the object to be polished 4, respectively. By sliding with a speed ratio, the object to be polished 4...
It is possible to distinguish between the front and back sides by making the upper and lower surfaces of the machine have different finished states.

In this way, in the polishing method using the secondary polishing device, the workpiece 4 is held and rotated in a horizontal plane, and the workpiece 4 is held between the upper and lower surface plates 7 that sandwich the workpiece 4 from above and below. By synchronously reciprocating the plate 1 in opposite left and right directions and making the moving speeds of the upper surface plate 7 and the lower surface plate 1 different from each other, the upper and lower surfaces of the object to be polished 4 are brought into different states. It will be polished to The object to be polished 4... always draws a circular orbit with a constant angular velocity, and a constant sliding motion is applied to each of its upper and lower surfaces, and its flatness and parallelism are Machining accuracy such as degree of accuracy becomes extremely excellent. Moreover, at the same time, polishing is performed with different finished surfaces on the front and back surfaces of the objects 4 to be polished.

In addition, in the apparatus of the above embodiment, the lower rack 2 and the upper rack 8
Reversing feed gear 3.3 with different diameters of upper and lower teeth between
Although we have arranged multiple gears in combination,
In short, any configuration may be sufficient as long as the lower surface plate 1 and the upper surface plate 7 are horizontally reciprocated in mutually opposite directions in synchronization, and are linked to each other so that the moving speeds thereof are different. For example, the pitch of the teeth of the lower rack 2 and the upper rack 8 may be made different if necessary.

Furthermore, instead of rotating the reversing feed gear 3.3, at least one side of the lower surface plate 1 or the upper surface plate 7 may be reciprocated left and right.

Further, in the above description, only the polishing of the object 4 to be polished by the horizontal rotation of the upper and lower surface plates 7.1 is mentioned, but the polishing apparatus of the present invention is not limited to this. , object to be polished 4
By changing the holding structure of . . . , it is possible to easily polish this by vertically rotating or tilting movement.

In the apparatus of the above embodiment, for example, if the anti-transfer gears 3, 3 are removed, the upper surface plate 7 is held fixed, and only the lower surface plate 1 is reciprocated from side to side, the object to be polished 4. ...The upper surface is polished by constant rotation, and the lower surface is polished by constant rotation and horizontal reciprocating motion, which also makes it possible to distinguish between front and back surfaces. I can do it.

As explained above, this invention holds a wafer as an object to be polished, rotates it in a horizontal plane, and synchronously reciprocates the upper surface plate and lower surface plate that sandwich the wafer from above and below in opposite left and right directions. The upper and lower surfaces of the wafer are polished to different conditions by moving the upper and lower surfaces at different speeds, resulting in high precision due to constant rotation and horizontal reciprocating motion for each of the upper and lower surfaces of the wafer. By thorough polishing, it is possible to distinguish between the front and back sides.

Since polishing is performed using a simple horizontal reciprocating motion, even if the wafer has a large diameter, it can be polished with high accuracy and uniformity.

[Brief explanation of the drawing]

Fig. 1 shows an example of a conventional polishing apparatus, (A) is a plan view of a block with a wafer attached, (B) is an iF@ side view of the main part, and Fig. 2 is a polishing apparatus of the present invention. (A) 4-1 is a schematic plan view thereof, and (B) is a schematic front view thereof. 1...Lower surface plate, 2...Lower rack, 3.
...Reverse feed gear, 4...Object to be polished (
wafer), 5...carrier, 6...
・Guide gear, 7... Upper surface plate, 8...
upper rack.

Claims (2)

[Claims] (1) The wafer is held and rotated in a horizontal plane, and the upper and lower surface plates that sandwich the wafer from above and below are synchronously reciprocated in opposite left and right directions, and the upper and lower surface plates are A wafer polishing method characterized by polishing the top and bottom surfaces of the wafer to different states by changing the moving speed. (2) A disk-shaped carrier that holds one or more objects to be polished and has teeth formed on its outer periphery, and the teeth mesh with the outer periphery of the carrier to hold the carrier at a predetermined position about the upper and lower axes. two or more guide gears to be rotated; an upper surface plate and a lower surface plate that sandwich the workpiece held in the carrier from above and below and are capable of reciprocating from side to side; and each side of the upper surface plate and the lower surface plate. 2.4 installed on the side and facing vertically,
V 7 L r J'l A〃) Bow n)/)ltFI
JflFile meat kVrm is seen and the reversing feed gear has different gear eaves where it meshes with each of the upper and lower racks,
A wafer polishing apparatus comprising: a drive mechanism that moves at least one of the upper surface plate, the lower surface plate, and the reversing feed gear.