JPS5922117Y2 - Sample holding device for chemical etching - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sample holding device used for processing a disk-shaped sample such as a silicon wafer in a chemical etching solution.

When etching only a specific region of a disk-shaped sample such as a silicon wafer, conventionally, a device as shown in FIG. 1 has been used to hold the sample.

In the figure, 1 is the main body of the sample holding device, on which the sample 2 is placed, and an etching-resistant adhesive 3 such as avinisine wax is applied to the periphery of the sample 2 and the outer part of the main body 1 from the sample 2. and fix the sample 2 to the main body 1.

A support rod 4 and a crossbar 5 are attached to the main body 1 to which the sample 2 is fixed, and the sample is immersed in an etching liquid 11 in a tank 10.

Since the adhesive 3 hardly dissolves in the etching solution, only the surface of the sample on which etching is desired comes into contact with the etching solution, and the other surfaces are protected by the main body 1 and the adhesive 3.

Rotation is applied to the sample holding device through a rotating shaft 6 as necessary.

After a predetermined period of time, the sample and holding device are taken out of the etching solution and washed with water.

Thereafter, the adhesive 3 is dissolved with a solvent and the sample 2 is removed from the main body 1.

The etching process for sample 2 is thus completed, but in the case where the sample is fixed with adhesive in this way, it takes time to attach and detach the sample.

ii When fixing the sample with adhesive or removing the adhesive from the sample, the dissolved adhesive contaminates the sample surface.

There are drawbacks such as.

The present invention provides a sample holding device suitable for chemical etching of silicon wafers, which eliminates these drawbacks.

FIG. 2 shows a sample holding device according to the invention.

In the figure, 20 is a disk-shaped sample such as a silicon wafer, and 21
Reference numeral denotes a main body of the sample holding device, which is provided with a recess 22 that is slightly thicker than the main body in which the sample 20 is placed.

Reference numeral 23 denotes a sample holding plate, which is formed into an annular shape with an inner diameter smaller than the outer diameter of the sample 20.

24 is a screw for fixing the sample holding plate 23 on the main body 21; 25 is a rubber elastic ring interposed in a compressed state between the bottom surface of the recess 22 of the main body 21 and the periphery of the back surface of the sample 20; 26; 27 is a reinforcing disk that supports the back surface of the sample 20; 28 is a support rod of the sample holding device; 29 is a support A crossbar 130 that connects the bars is a shaft that transmits the rotational motion of the motor.

Next, as an embodiment of the present invention, a case where the present invention is applied to etching processing for thinning the center of a silicon wafer will be described.

Sample 20 is a silicon wafer with a diameter of 50 mmφ and a thickness of 200 μm, and the area of the thin section is about 45 m in the center.
mφ, and the thickness of the thin section is 10 μm or less.

Main body 21. The sample holding plate 23 and the fixing screws 24 were made of Teflon (trade name) so as not to be corroded by the etching solution, and the elastic ring 25 was an "O" ring for vacuum equipment.

When setting the sample 20, the main body 21 and the support rod 28 are separated, and the rubber elastic ring 25 is placed on the bottom surface of the recess 22 of the main body 21.

On top of this, the sample 20 was placed via a Teflon disk 27 with a diameter of 50 mmφ and a thickness of 2 mm, and then a disk with an outer diameter of 50 mm
A thin Teflon plate 26 with a diameter of 45 mm and a thickness of 1 mm is placed on the sample 20, and the sample holding plate 23 is fixed to the main body 21 with screws 24.

At that time, the rubber elastic ring 25 is compressed, and its repulsive force causes the sample 20 and the thin plate 26, and the thin plate 26 and the sample holding plate 2 to
The dimensions of each part are determined so that the sample holding plate 23 and the main body 21 are brought into close contact with each other by tightening the screws.

This completes the setting of the sample, and then attaches the support rod 2 to the main body 21.
Install 8.

24° mixed hydrofluoric acid, acetic acid, and nitric acid in a volume ratio of 1:2:4
Set sample 20 in the etching solution at ±0.5°C as described above! - Etching was carried out by immersing the sample holder in the sample holder while applying rotational and orbital motion to the sample holder.

After 30 minutes, the sample holder was washed with water, the screw 24 was loosened, and the sample 20 was taken out. When the sample 20 was removed from the sample holder, it was found that the etching solution was completely prevented from penetrating the contact surfaces of the sample holding plate 23, the thin plate 26, and the sample 20. Approximately 45 m in the center of 20
Only the region mφ was thinned by etching.

In this example, the disk 27 was used for reinforcement to prevent the sample from breaking due to a decrease in mechanical strength due to thinning of the sample 20. However, if the strength of the sample after etching is sufficiently large, the disk 27 is unnecessary.

In addition, the thin plate 26 was used to improve the adhesion with the sample 20, but if the sample holding plate 23 is made of a material with good adhesion such as Teflon, the thin plate 26 can be omitted.
There is no problem even if the peripheral part of the surface of the sample 20 is brought into direct contact with the opposing surface of the sample holding plate 23.

As explained above, in the present invention, the repulsive force of the rubber elastic ring interposed between the bottom of the recess of the sample holding device main body and the periphery of the back surface of the sample causes the periphery of the front surface of the sample and the opposing surface of the sample holding plate to Because it is configured to have a structure in which the space between the etching parts is in close contact with each other, it is possible to completely prevent the etching liquid from penetrating into the parts of the sample that do not require etching without using adhesives, and the rubber elastic ring is also prevented from being affected by the etching liquid. do not have.

As a result, it is possible to provide a sample holding device for chemical etching that allows the sample to be attached and detached efficiently in a short period of time, and in which the sample surface is not contaminated with adhesive.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional sample holding device, and FIG. 2 is a sectional view of a sample holding device according to the present invention. Explanation of symbols, 20: Sample, 21: Main body, 22: Recess, 2
3: Sample holding plate, 24: Fixing screw, 25: Rubber elastic ring.

Claims (1)

[Scope of utility model registration request] A sample holding device used for processing a disc-shaped sample in a chemical etching solution consists of a main body made of an etching-resistant material with a recess slightly thicker than the sample into which the sample is placed, and an inner diameter that is larger than the sample. A sample holding plate made of an etching-resistant material formed into an annular shape smaller than the outer diameter, screws for fixing the sample holding plate onto the main body, and a bottom surface of the four parts of the main body and a peripheral part of the back surface of the sample. A rubber elastic ring is provided in a compressed state in between, and the repulsive force of the rubber elastic ring brings the surface periphery of the sample into close contact with the opposing surface of the sample holding plate. Sample holding device for chemical etching.