JPH03154771A - Polishing device - Google Patents

Abstract

PURPOSE:To feed a uniform abrasive liquid to the body to be worked by providing a polishing pad in the structure of having a liquid flowing property in the vertical direction and a polishing tray having the liquid leading passage communicating to the upper face from the internal part on a polishing face. CONSTITUTION:An abrasive liquid is fed from the lower part to the work face of the body 1 to be worked via a pipe 16, leading ring 11, T shaped hole 10, liquid leading pass P and the polishing pad 5 by operating a pump 15, in the state of rotating a polishing tray 7 and the polishing pad 5 by rotating a motor 13. Accordingly, the abrasive liquid is uniformly fed to the surface of the body 1 to be worked and so a good work face can be obtained without the polishing face being blurred and the surface roughness becoming larger.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polishing apparatus that performs high-precision polishing of semiconductor materials and optical materials.

[Conventional technology]

Conventionally, silicon single crystal and compound semiconductor substrates have been processed with high precision.
Although it is not shown in the drawing, the polishing device that performs distortion-free processing is equipped with a polishing plate to which a polishing bat is bonded, and a liquid guide path for supplying polishing liquid onto the polishing plate. A polishing pad is brought into opposing contact with the polishing pad, and the surface of the workpiece is polished by relative movement between the polishing pad and the workpiece.

Further, as a method of supplying polishing liquid to this polishing apparatus, a method is used in which the polishing liquid is injected from above onto the surface of the polishing pad immediately before the workpiece or near the center of rotation.

[Problem to be solved by the invention]

In the conventional polishing apparatus described above, the polishing liquid is supplied to the workpiece from the outer periphery of the workpiece, so there is a difference in the polishing liquid supply state between the outer periphery and the vicinity of the center of the workpiece. When the workpiece becomes large, the supply of polishing liquid becomes insufficient near the center, and the polishing surface becomes cloudy or the surface roughness becomes large, and a sufficient surface condition may not be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing apparatus capable of uniformly supplying polishing liquid to the entire surface of a workpiece by solving the above-mentioned conventional problems.

[Means to solve the problem]

The polishing apparatus of the present invention places a workpiece on a polishing pad bonded to the upper surface of a rotatable polishing surface, facing the polishing pad, and while supplying polishing liquid, the workpiece is placed between the polishing pad and the workpiece. In a polishing apparatus that processes a workpiece by relative motion, the polishing pad has a structure that allows liquid to pass in a direction perpendicular to the polishing surface, the polishing surface has a liquid guide path leading from the inside to the upper surface, and the polishing surface has a liquid guide path that leads from the inside to the upper surface. It also has the function of supplying polishing liquid to the liquid path.

〔Example〕

The present invention allows the supply of polishing liquid to pass through from below the polishing pad and directly act on the machined surface of the workpiece, thereby uniformly supplying the polishing liquid to the surface of the workpiece and obtaining a good polished surface. be.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the polishing apparatus of the present invention. As shown in the figure, this polishing device includes a disc-shaped holder 2 that holds a thin plate-shaped workpiece 1 on its lower surface by a method such as gluing, and an arm 4 that is connected to the center of the upper surface of this holder 2. a round rod-shaped support rod 3 that is inserted into and held in the hole and can follow and follow the surface of a rotating disk-shaped polishing pad 5; and a main body 6 that fixes the other end of the arm 4;
a polishing pad 5 adhered to the upper surface of a disc-shaped polishing surface 7;
A shaft 8 integrated with the polishing surface 7, and a shaft 8 located inside the polishing surface 7 and provided above the shaft 8? =.

A liquid guide path 9 that leads to a plurality of holes, and a shaft 8 that connects this liquid guide path 9 with the shaft 8.
An introduction ring 11 is connected to the outer periphery of the shaft 8 to rotatably hold the shaft and supply polishing liquid from the outside to the rotating T-type 10 of the shaft 8. A seal 12 is provided to prevent liquid from leaking between the outer circumferential part, a motor 13 has a rotating shaft connected to the end of the shaft 8, and rotates the polishing surface 7 and the polishing pad 5 via the shaft 8. Pump the liquid15
, into the inlet ring 11 through the tube 16 and into the T-type 10. The polishing liquid tank 14 is configured to supply a polishing liquid to the back surface of the polishing pad 5 through a liquid guide path 9.

FIG. 2 shows an enlarged view of the vicinity of the workpiece of an embodiment of the polishing apparatus of the present invention. In addition, as shown in the figure, the polishing pad of this polishing device is formed by heating and sintering fine resin particles, and has a structure with a space between them, so that the polishing liquid can pass from the back side of the pad to the front surface. can. Next, a case will be described in which a workpiece is polished using the polishing apparatus of this embodiment. First, while the motor 13 is rotated to rotate the polishing surface 7 and polishing pad 5, the pump 15 is operated to pump the polishing liquid into the tube 16. Introduction ring 11. T-shaped hole 10, liquid guide path 9
．． It is supplied from below to the processing surface of the workpiece through the polishing pad 5. As a result, the polishing liquid is uniformly supplied to the surface of the workpiece, so that the polished surface does not become cloudy or the surface roughness becomes large, and a good machined surface can be obtained.

Here, with a polishing apparatus having the above configuration, for example, a silicon single crystal wafer with a diameter of 150 mm is used as a workpiece, and a sintered polyethylene oxide (average particle size: 100 μm) is used as a polishing pad.
), when polishing was performed using a commercially available 10% colloidal silica aqueous solution (manufactured by Nissero Kagaku, trade name Nisnortex 30) as a polishing liquid, a mirror surface with a surface roughness of 5 nm or less from the edge to the center of the wafer was obtained. I was able to get it. If only the conventional polishing liquid supply method is used under the same conditions, a similar mirror surface will be obtained at the edges of the wafer, but at the center, the supply of polishing liquid will be insufficient and clouding will occur, resulting in surface roughness. Saha 20
It gets worse than nm.

In addition, in this example, the case where the structure of the polishing pad is a sintered resin structure has been described, but in order to realize this example, it is necessary for liquid to pass in the cross-sectional direction of the polishing pad.
A similar effect can be obtained by forming microholes or grooves in a regular foamed polyurethane polishing pad or a polyester nonwoven polishing pad. Furthermore, although the structure of the liquid guiding path has been described in which the polishing liquid is supplied from a hole provided in the surface in contact with the polishing pad, the same effect can be obtained even if the polishing liquid is supplied from a groove or a hole in a porous material.

〔Effect of the invention〕

As explained above, the present invention provides a polishing pad through which a polishing liquid passes, and further provides means for passing the polishing liquid from the bottom surface of the polishing pad to the polishing surface, thereby uniformly supplying the polishing liquid to the workpiece. Even if the workpiece becomes larger, cloudiness or surface roughness will not increase.
This has the effect of providing a polishing device that can process a good polished surface.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the polishing apparatus of the present invention, and FIG. 2 is an enlarged view of the vicinity of the workpiece of the embodiment of the polishing apparatus of the present invention. 1... Workpiece, 2... Holder, 3... Support rod,
4... Arm, 5... Polishing pad, 6... Main body,
7... Polishing plate, 8... Shaft, 9... Liquid guide path, 10...
...T type, 11...Introduction ring, 12...Seal, 1
3...Motor, 14...Polishing liquid tank, 15...
Pump, 16...tube.

Claims (1)

[Claims] A workpiece is placed facing the polishing pad bonded to the top surface of a rotatable polishing plate, and the workpiece is moved by relative movement between the polishing pad and the workpiece while supplying polishing liquid. In a polishing apparatus for processing, the polishing pad has a structure that allows liquid to pass in a direction perpendicular to the polishing surface, the polishing dish has a liquid guide path leading from the inside to the upper surface, and a polishing liquid is supplied to the liquid guide path. A polishing device characterized by having the function of