JPH0234746B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a polishing cloth cleaning method capable of cleaning a polishing cloth for a double-sided polishing device with high efficiency.

(Prior Art) In a double-sided polishing device (also referred to as a polishing device), polishing cloths attached to both upper and lower surface plates become clogged due to double-sided polishing. For example, when a silicon wafer is polished on both sides with a silica gel-based abrasive or a colloidal silica-based abrasive, if polyurethane foam or polyurethane-impregnated nonwoven polyester fabric is used as the polishing cloth, the polishing cloth will be damaged by the abrasive and polished silicone debris. This causes clogging, which can reach several hundred μm in size after several hours of polishing. Such clogging has negative effects such as a reduction in the processing speed in double-side polishing, the processing accuracy of the polished wafer, and the generation of scratches on the wafer surface. For this reason, various methods have been implemented to remove clogging of the polishing cloth and to clean the surface of the polishing cloth. One method is to use a sharp knife to squeeze the surface of the polishing cloth to remove clogged areas. There is also a method of cleaning the surface of the polishing cloth by squeezing it with a knife after each polishing process. However, this method is time-consuming and ineffective, and only covers a small number of surfaces.
It has an advantage only up to a depth of 10 μm. In addition, removing clogging of the polishing cloth on the upper surface plate side using the above method,
Not only is it virtually ineffective in terms of work, but it also has the disadvantage of being extremely inefficient because you are working with your head up.

Another method is to insert a cylindrical brush between the upper and lower surface plates and apply relative rotation to both the upper and lower surfaces to remove clogging and clean the polishing cloth. With this method, the amount of wear on the brushes differs between the inner and outer sides of the surface plate, which shortens the life of the brushes, and the degree of cleaning to remove clogs differs on the polishing cloth. I had the inconvenience of not being able to do so.

(Problems to be Solved by the Invention) The present invention has been made to eliminate the above-mentioned disadvantages, and is an abrasive cloth cleaning method that uniformly and efficiently unclogs the abrasive cloth without bothering the human labor. The purpose is to provide a method.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention provides a polishing cloth cleaning method for cleaning a polishing cloth for a double-sided polishing device, in which a brush is implanted on one main surface of a planetary gear. The brush body is meshed between the sun gear and the internal gear, and with the brush body interposed between the upper and lower surface plates, the sun gear and the internal gear are driven to cause the brush body to move planetarily, and the polishing cloth The polishing cloth is cleaned with a brush, and the clogging of the polishing cloth can be removed uniformly and efficiently without the need for manpower or special equipment.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

1 to 4 show a brush body 10 used in an abrasive cloth cleaning method according to an embodiment of the present invention. Here, 1 is a planetary gear formed by carving teeth 2,... on the outside of an annular plate-shaped member made of synthetic resin, and its module is the same as the sun gear 3 and internal gear 4, and both gears 3, 4 They are engaged and rotated. One main surface 5 of this planetary gear 1
A brush 8 made of a nylon wire bundle is embedded in an annular shape near the outer periphery of the brush body 10 to constitute a brush body 10. The structural specifications of this embodiment and related parts are as follows: Upper and lower surface plates 15 and 17 have an outer diameter of 840 mm, an inner diameter of 265 mm,
Sun gear 3 pitch circle diameter 241.3mm, module
2.1, pitch circle diameter of internal gear 4 863.5mm,
It is module 2.1. The planetary gear 1 has a pitch circle diameter of 311.1 mm, a module of 2.1 mm, a material of nylon 66, and a thickness of 15 mm. On the other hand, the nylon wire bundle of brush 8 has a wire diameter of 0.4 mm and is bundled to have a diameter of 4 mm.
These were arranged in three rows in the radial direction and had a width of 15 mm. Then, the center of the width is the radius from the center of planetary gear 1.
It was implanted in a circular ring shape of 73 mm.
Also, the length of the nylon wire bundle that makes up the brush 8 is
It was set to 10mm.

Next, a polishing cloth cleaning method according to an embodiment of the present invention using the brush body 10 having the above structure will be described.

First, the cleaning brush body 10 is mounted on the polishing cloth 16 of the lower surface plate 15 with the planetary gear 1 meshing with the sun gear 3 and internal gear 4 of the double-sided polishing device. At this time, it is preferable to take symmetry into consideration and attach four brush bodies 10 of the same type. If the brush 8 is on one side, the third
As shown in Figure 4, two of the four pieces are brushed 8
Attach it so that it faces upward, and install the other two so that it faces downward. At this time, alternately place them facing upward and downward at 90 degree intervals. Next, the upper surface plate 17 is lowered so that the surface of the polishing cloth 18 attached to the upper surface plate 17 comes into contact with the tip of the brush 8, and then lowered further by about 1 mm to 2 mm to deform the tip of the brush 8. . Next, the upper and lower surface plates 15,1
7. Rotate the sun gear 3 and internal gear 4 at the same number of rotations as under normal polishing conditions. In this embodiment, the upper surface plate 17 rotates at 20 revolutions per minute, and the lower surface plate 15
rotates at 60 revolutions per minute, the sun gear 3 at 30 revolutions per minute, and the internal gear 4 at 19 revolutions per minute, and pure water is poured into the abrasive supply hole 20 on the upper surface plate 17 side. When the double-sided polishing device is operated as described above, the brush 8 revolves around the sun gear 3 while rotating on its own axis.
The polishing cloths 16 and 18 are cleaned.

Incidentally, 20 4-inch silicon wafers were repeatedly polished on both sides with colloidal silica polishing agent and polyurethane-impregnated polyester nonwoven cloth, and after 10 times, the polishing agent and silicone polishing debris were deposited on the surfaces of polishing cloths 16 and 18. A wide area of clogged areas colored light brown is formed on the polishing cloths 16 and 18, but when these polishing cloths 16 and 18 are cleaned for 2 minutes using the above method, the colored areas are completely removed and the polishing cloths 16 and 18 are restored to their original state. The color had returned to normal and the clogging had been removed.

In the above embodiment, the brush 8 is provided on one side.
Although a brush body 11 with brushes 8, 8 provided on both sides as shown in Fig. 5 may be used.
Further, as shown in FIG. 6, when the brush body 13 is provided with the groove 12 on the other surface, when the upper surface plate 17 is raised, it is possible to prevent the problem of the brush body 13 coming into close contact with the upper surface plate 17 and rising together with the upper surface plate 17.

[Effects of the Invention] As explained above, the polishing cloth cleaning method of the present invention provides a double-sided polishing device in which a brush body, which is formed by implanting a brush on one main surface of a planetary gear, is attached to a sun gear and an internal gear. With the brush body interposed between the upper and lower surface plates, the sun gear and internal gear are driven to cause the brush body to move planetarily, and the polishing cloth is cleaned by the brush. A special effect is achieved in that cloth can be cleaned uniformly and with high efficiency without requiring any manual labor or additionally installing a special device.

[Brief explanation of drawings]

FIG. 1 is a front view of a brush body used in an abrasive cloth cleaning method according to an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 illustrates an attached state of the brush body of FIG. 1. 4 is a sectional front view of the main part of FIG. 3, and FIGS. 5 and 6 are a brush body used in the polishing cloth cleaning method according to an embodiment of the present invention. It is a front view showing a modification of . 1: Planetary gear, 3: Sun gear, 4: Internal gear, 8: Brush, 10: Brush body, 15: Lower surface plate, 16: Polishing cloth, 17: Upper surface plate, 18: Polishing cloth.

Claims (1)

[Claims] 1. A sun gear that is rotationally driven, an internal gear that is coaxial with the sun gear and is arranged on the outer circumferential side thereof and is rotationally driven, and a holding hole that holds a wafer between the sun gear and the internal gear. a carrier plate that is disposed in mesh with each other and moves planetarily around the sun gear following the rotation of the sun gear and the internal gear; and a pair of rotation constants that are disposed above and below the carrier plate. and a polishing cloth attached to these rotary surface plates, and the wafer held in the holding hole of the carrier plate is compressed by the pair of rotary surface plates through the polishing cloth, thereby polishing the wafer. In the polishing cloth cleaning method for cleaning the polishing cloth of a double-sided polishing device for polishing both sides of the
A step of meshing a planetary gear having a brush on at least one of the front and back surfaces with the sun gear and the internal gear instead of the carrier plate, and polishing between the pair of rotating surface plates. After the planetary gear is inserted through a cloth, the rotary surface plate is rotated, and the sun gear and the internal gear are also rotated to cause the planetary gear to make a planetary motion. An abrasive cloth cleaning method comprising the step of cleaning the abrasive cloth.