JPH0440848Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a polishing machine that can achieve highly accurate polishing.

(Prior Art) In a conventional polishing machine, a wafer as a workpiece is attached to the back surface of a plate, and the plate is pressed by a pressing means to perform polishing.

As the pressing means, there is a type in which a processing plate is provided at the tip of a rod of a cylinder device that can move forward and backward. In this pressing means, when the cylinder device is pressurized and the rod extends, the plate and wafer are both pressed toward the turntable by the pressing plate, and the wafer is polished by rotation of the turntable.

(Problems to be Solved by the Invention) However, the above conventional plate pressing mechanism has the following problems.

In a polishing machine, a plurality of wafers are attached to the lower surface of a plate, pressed against the polishing surface of a turntable by a pressure plate, and polished by rotation of the turntable. At this time, the plate also polishes the wafer while being rotated by the rotational force, but due to the rotational movement, the wafer is unevenly worn due to the difference in speed between the center portion of the plate and the peripheral portion of the plate. Further, foreign matter may enter between the pressure plate and the plate, causing a local difference in the pressure of the pressure plate against the plate, which also causes uneven wear. In order to prevent or correct these problems, it is possible to adjust the balance between the pressure at the center and the periphery of the plate, but conventional pressure plates are designed to press only the center of the plate; The force applied to the part is small. That is, it has not been possible to make the force applied to the peripheral portion of the plate greater than the force applied to the center.

In this way, traditional polishing machines
There was a problem in that it was not possible to adjust the balance of forces applied to the peripheral portion and the central portion of the plate.

Therefore, this invention is intended to solve the above-mentioned problems, and aims to provide a polishing machine in which the balance of the pressing force applied to the plate can be adjusted.

(Means for Solving the Problems) This invention has the following configuration in order to solve the above problems.

That is, in a polishing machine that polishes a plate with a wafer attached to its back surface while pressing it against the polishing surface of a turntable using a top ring, a cylindrical portion is provided to press the peripheral edge of the plate against the bottom surface of the top ring. A pressing body for pressing the central part of the plate is provided at the inner central part of the top ring, and is positioned relative to the top ring through a cylinder chamber formed between the top ring and the pressing body. A weight is disposed on the top ring, and a fluid supply section is provided for supplying fluid to the cylinder chamber to press the pressing body toward the plate. do.

(effect) Next, we will discuss the effect.

Fluid is supplied to the sealed space between the top ring and the pressing body to polish the wafer while adjusting the pressure balance with the top ring or the pressing body.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

In FIG. 1, 10 is a rod protection pipe, the upper end of which is connected to the main body of the polishing machine (not shown).

A lower rod 12 is shaped like a hollow pipe, and its upper end is connected to a cylinder device (not shown) fixed to the main body of the polishing machine.

14 is a rotary joint, and the upper part of this rotary joint 14 is fixed inside the lower rod 12 via a bolt. Furthermore, compressed air is fed into the upper part of the rotary joint 14 via a rubber hose 18 from a compressor (fluid supply section), not shown.

Reference numeral 20 denotes a top ring, and a through hole 22 is formed in the center thereof, through which the lower rod 12 and the like pass through. Further, a contact portion 24 extends downward along the bottom periphery of the top ring 20. An O-ring 28 is fitted to the lower end of the contact portion 24 to ensure close contact with the plate 26.

30 is an outer cylinder, and a hollow tapered screw 32 provided at the lower end of the rotary joint 14
At the same time, it is fixed to the top ring 20 via a bolt 34.

36 is a piston, which is movable in the vertical direction within the outer cylinder 30. The piston 36 is the outer cylinder 30
Inner cylinder 38 made of Delrin (registered trademark) placed inside
However, in order to ensure airtightness between the piston 36 and the inner cylinder 38, the piston 36 is equipped with an airtight packing 4.
0 is inserted. That is, the piston 36 and the outer cylinder 30 constitute a cylinder chamber 60.

42a, 42a are pins that prevent the piston 36 from rotating.

Reference numeral 44 denotes a pressing body, which is formed to have an arbitrary size and is fixed to the lower end of the piston 36. O-rings 46a and 46b are also arranged on the bottom surface of the pressing body 44 to improve adhesion to the plate 26. It is preferable that the O-ring on the lower surface of the pressing body 44 can be adapted to the size of the wafer 48 by changing its position. In place of the O-rings 46a and 46b, in order to improve the adhesion with the plate 26,
A sheet pad made of artificial leather or rubber may also be attached. It is even better if the sheet packing is also provided with grooves and depressions on the surface facing the plate 26.

50 are weights which are stacked on top of the top ring 20 to apply pressure to the top ring 20. Weight 50... is fixing bolt 5
2a and 52b are fixed to the top ring 20.
Furthermore, the weight 50... is the housing 54a, 5
4b.

In addition, 26 is a plate, and the wafer 48...
...is pasted on the bottom surface.

56 is a turntable, with a cross 5 on the top.
8 is stretched, and the wafers 48 . . . are polished by this cloth 58.

Furthermore, the operation of the polishing machine will be explained.

First, an appropriate number of weights 50... (for example, the total weight weight is 340 kg) is placed in a stack on the top ring 20, and the fixing bolts 52a, 5
Fix it at 2b.

On the other hand, the wafer 48 to be polished is placed on the plate 2.
6. Attach an appropriate number of sheets to the bottom surface of the turntable 56.
Set it on the cross 58 side. Then, the lower rod 12 is lowered to bring the pressing body 44 into contact with the center of the plate 26, and compressed air is sent into the cylinder chamber 60 from a compressor (not shown) via the rubber hose 18 and the rotary joint 14. The cylinder chamber 60 is configured to be airtight, and the compressed air presses the piston 36 downward.
As a result, the pressing body 44 pushes the plate 26 downward,
Press with a predetermined pressing force (for example, with a force of 150 kg).

The contact portion 24 of this top ring 20 and the pressing body 4
The plate 26 is pressed against the wafer 48 by the pressing force of 4.
... is pressed against the cross 58 surface of the turntable 56. When the turntable 56 rotates, the lower rod 12 and the members other than the upper part of the rotary joint 14 rotate around the rod protection pipe 10 and the lower rod 12 by the rotational force of the turntable 56. As the turntable 56, plate 26, etc. rotate, the lower surfaces of the wafers 48 are polished by the cloth 58.

In the polishing machine that performs the above operation, the pressure of the compressed air introduced into the cylinder chamber 60 is 0.
In this case, the pressing force acting on the plate 26 is only the load of the weight 50... via the O-ring 28 arranged on the lower surface of the contact part 24 of the top ring 20,
Pressure is applied to the plate 26 only near its periphery.

Therefore, compressed air is introduced into the cylinder chamber 60,
As the air pressure is gradually increased, the pressure exerted by the pressing body 44 on the center of the plate 26 gradually increases.
At the same time, the pressure near the peripheral edge of the plate 26 decreases, and eventually the two are balanced. This pressure-balanced state is the condition under which the wafers 48 can be flatly polished, and ideal polishing can be achieved by adjusting the pressure of the compressed air introduced into the cylinder chamber 60.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments. For example, the means for urging the piston downward is not limited to air pressure, but may also be fluid such as hydraulic pressure. Of course, many modifications can be made without departing from the spirit of the invention.

(Effects of the invention) The polishing machine according to the invention is capable of polishing while adjusting the balance between the peripheral edge and the center of the plate.

For this reason, it is possible to increase the pressure applied to the periphery of the plate, or to increase the pressure applied to the center, and even if the wafer has uneven wear such as internal or external shear, the pressure can be balanced. It is possible to perform polishing while correcting the amount of polishing of the wafer by adjusting the amount of polishing, and it is possible to perform polishing with even higher precision.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing the plate pressing mechanism of the polishing machine of the present invention. 20... Top spring, 26... Plate, 3
6... Piston, 44... Pressing body, 48... Wafer, 50... Weight, 60... Cylinder chamber.

Claims (1)

[Claims for Utility Model Registration] In a polishing machine that polishes a plate with a wafer attached to its back surface while pressing it against the polishing surface of a turntable using a top ring, the peripheral edge of the plate is pressed against the bottom surface of the top ring. a cylindrical abutting part for pressing the plate, and a pressing body for pressing the central part of the plate at the inner central part of the top ring, through a cylinder chamber formed between the top ring and the pressing body. A fluid supply section is provided so as to be movable toward and away from the top ring, but cannot be detached from the top ring, and a weight is disposed on the top ring, and a fluid supply section for supplying fluid to the cylinder chamber to press the pressing body toward the plate. A polishing machine characterized by the following: