JPH05285807A - Ultra-precision processing method - Google Patents

Abstract

(57) [Summary] [Purpose] Aiming at high efficiency and low cost by performing grinding and polishing with the same equipment. [Structure] In an ultra-precision grinding device with a rotational wobble of a grinding wheel head and a rotational wobble of a turntable carrying a processed body of 0.1 μm or less, ultra-precision grinding is performed using a grinding wheel to a surface roughness close to a mirror surface, Next, an ultra-precision machining method that removes the grinding wheel and replaces it with a polishing tool to perform mirror polishing in the same way as ultra-precision grinding. An ultra-precision machining method in which two sets of the same grindstone heads are arranged in parallel in the same super-precision grinder, a grinding grindstone is mounted on one side, and a polishing tool is mounted on the other side, and after finishing grinding, the workpiece is moved to perform polishing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method for electronic materials such as semiconductor wafers, hard disks, quartz substrates, and crystal oscillators, or for other glass, ceramics, and metals.

[0002]

2. Description of the Related Art Silicone wafers, hard disks,
Abrasive grindstones are generally used for grinding surface finishing of electronic materials such as quartz substrates and crystal oscillators, grinding of glass, ceramics or metal materials, and surface finishing. Grinding and polishing requires high polishing rate, low damage,
Although the cost is low, the demand for glass materials has increased with the recent technological advances of optical equipment and electronic equipment.
The demand for more precise finishing is increasing.

By the way, grinding and polishing are performed by completely different devices. It took a lot of time and trouble to change the setup, and it was difficult to guarantee accuracy. A method of performing rough grinding and precision grinding with two heads is already known, but this is also only between grinding.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to carry out grinding and polishing in the same device to improve efficiency and reduce cost.

[0005]

[Means for Solving the Problems] In a grinding device in which the rotational shake of a shaft of a grindstone holding member and the rotary shake of a turntable carrying a work piece are set to 0.1 μm or less, a surface roughness close to a mirror surface is obtained by using a grinding grindstone. It is also an ultra-precision processing method characterized by performing ultra-precision grinding, then replacing the grinding wheel with a polishing tool and performing mirror-surface polishing in the same manner as ultra-precision grinding.

Further, two sets of the same grindstone heads are arranged in parallel in the same super-precision grinding device, a grinding grindstone is mounted on one side, and a polishing tool is mounted on the other side, and a turntable for carrying a lower work piece after grinding is arranged. An ultra-precision machining method characterized in that a workpiece is moved and polished.

The polishing tool may be a grinding stone in the form of a grinding stone containing abrasive grains, or a sheet-shaped polishing cloth attached to a substrate in the form of a grinding stone. In the latter case, an abrasive containing fine abrasive grains is supplied as needed.

[0008]

The present invention will be described with reference to the drawings. In FIG. 1, a grinding wheel 2 is held by a wheel head (grinding wheel) holder 1 and can be raised and lowered.

The grindstone head is capable of exchanging and holding various kinds of grindstones, and is rotated by a drive motor (not shown). The grindstone head is lowered and the grinding grindstone is rotated to cut into the surface of the workpiece 3 carried on the turntable 4 for grinding.

The turntable 4 is fixed to the moving slide 5 and can move on the slide base 6. In this case, the rough grinding, the finish grinding, the polishing, and the final grinding can be performed by one apparatus by exchanging the grindstone.

In the case of FIG. 2, the same grindstone heads 1 as described above are installed side by side in parallel, and the slide 7 common to the two grindstone heads and the turntable 4 to one workpiece moving slide 5 are arranged.
Is placed, and the workpiece is supported on the turntable 4. In this case, a grinding wheel is attached to one side and a polishing tool is attached to the other side, and after finishing the grinding, the workpiece is moved to perform the polishing.

In the present invention, the grinding grindstone and the polishing grindstone can be mounted and used in the same grinder because the rotational shake of each of the turntable and grindstone head of this grinder is 0.1 μm or less. By using such a device, it is possible to attach a sheet-like polishing cloth to a polishing grindstone or a grinding grindstone-like substrate after grinding and perform precise polishing using a polishing liquid.

As described above, once the processed body is carried on the turntable, it can be processed until the final polishing without detaching the processed body, so that high processing accuracy can be obtained and at the same time the efficiency is extremely high.

[0014]

【Example】

(Example 1) In an ultra-precision grinding machine having only one set of grinding wheel heads, a cup-shaped # 2000 vitrified bond diamond grinding wheel (outer diameter 200 m)
m, working surface width 3 mm), the grindstone head is lowered and rotated at 2000 rpm.

Installed on the turntable, 500 rpm
When the grinding wheel is brought into contact with the Si wafer in such a position that the rotation center of the Si wafer having a diameter of 150 mm passing through the grinding stone approximately the center of the grinding wheel working surface is passed and the grinding speed is lowered at a cutting speed of 10 μm / min for 2 minutes, Surface roughness Rmax
A pseudo mirror surface of 0.2 μm was obtained.

Next, the grindstone was exchanged, and BaC having a particle diameter of 3 μm was used.
A Si wafer polishing grindstone containing O ₃ powder in a volume ratio of 50% was attached, and the procedure was similar to the above grinding, except that the grindstone head was lowered at a cutting speed of 1 μm / min to polish for 2 minutes. A distorted mirror surface was obtained. Moreover, the flatness of the entire wafer was as good as 0.8 μm.

(Embodiment 2) In an ultra-precision grinding machine having two sets of grinding wheel heads, a cup-shaped # 2000 vitrified bond diamond grinding wheel (outer diameter 200 mm, working surface width 3 mm) was mounted on the first grinding wheel head, and A polishing tool in which a non-woven cloth polishing cloth is attached to the working surface of an aluminum alloy base having the same shape and size as the cup-shaped grinding wheel (however, the working surface width is 50 mm) is mounted on the whetstone head.

A turntable on which a Si wafer having a diameter of 150 mm is installed is installed on a moving slide, and moves on a slide base so that the same processing can be performed by both the first grinding wheel head and the second grinding wheel head.

First, the first grindstone head is used for the above (Example 1).
Grinded in the same way as done in Rmax 0.2 μm
I got a pseudo mirror surface. Next, the turntable is moved to below the second grindstone head, the Si wafer is arranged so as to have the same positional relationship as that at the time of grinding, and colloidal silica abrasive is supplied to the surface of the Si wafer at a flow rate of 5 liters / minute. While 1
After polishing for 2 minutes at a cutting speed of μm / min, Rm
A strain-free mirror surface of ax 7 nm was obtained. The flatness of the entire wafer was as good as 0.9 μm.

[0020]

Since grinding and polishing are continuously performed by the same grinding apparatus, higher efficiency, labor saving, higher accuracy, and lower cost can be achieved as compared with the case where separate conventional apparatuses are used.

[Brief description of drawings]

FIG. 1 is a polishing apparatus used in the method of the present invention.

FIG. 2 is another example of a polishing apparatus used in the method of the present invention.

[Explanation of symbols]

 1 Grinding grindstone holding part 2 Grinding grindstone 3 Workpiece 4 Turntable 5 Moving slide 6 Slide base

Claims (3)

[Claims] 1. In an ultra-precision grinding apparatus in which the rotational shake of a grinding wheel head and the rotational shake of a turntable carrying a workpiece are 0.1 μm or less, ultra-precision grinding is performed using a grinding wheel to a surface roughness close to a mirror surface. An ultra-precision machining method characterized in that the grinding wheel is removed and then replaced with a polishing tool to perform mirror surface polishing in the same manner as ultra-precision grinding. 2. The same ultra-precision grinding apparatus as in claim 1, two sets of the same grindstone heads are arranged in parallel, a grinding grindstone is mounted on one side, and a polishing tool is mounted on the other side. Ultra-precision processing method characterized by performing. 3. As the polishing tool, a grinding stone in the form of a grinding stone containing abrasive grains, or a sheet-shaped polishing cloth attached to a substrate in the form of a grinding stone to supply an abrasive containing fine abrasive grains as needed is used. The ultra-precision processing method according to claim 1 or 2.