JPS6015149B2 - How to polish indium phosphide crystal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for mirror polishing semiconductor crystal wafers, and more particularly to a method for mirror polishing indium phosphide crystal wafers.

Conventionally, when the semiconductor crystal is silicon, gallium arsenide, or gallium phosphide, mirror finishing has been performed using a polishing solution in which alumina particles are suspended in an alkaline aqueous solution as polishing particles.

For gallium arsenide, chemical polishing was performed using only a solution of bromine dissolved in alcohol, but in this case, the ``sagging phenomenon'' in which the edges of the wafer became rounded
There was a drawback that caused For the indium phosphide crystal that is the object of the present invention, a polishing liquid in which alumina is suspended in an alkaline aqueous solution has been used, but the effects of this are as follows.
This is substantially the same as a polishing liquid in which abrasive grains are suspended in water, and it not only tends to leave polishing scratches but also has the disadvantage of slow polishing speed.

The inventors used a polishing solution obtained by suspending alumina abrasive grains in acetic acid in which hydrogen bromide was dissolved.
An attempt was made to mirror polish an indium phosphide crystal, but it had the drawback of producing a silk-like pattern on the surface of the crystal.

The aim of the invention is to eliminate the above-mentioned drawbacks.

The above object of the present invention is characterized in that it uses a polishing liquid obtained by suspending abrasive grains in a solution in which bromine is dissolved in an organic solvent.

This can be achieved by a method of polishing indium phosphide crystals. Iron oxide or alumina is suitable as the abrasive grains used in the method of the present invention, and the grain size thereof is 0.05~
A range of 1 is preferable. Furthermore, as the organic solvent to be used, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, acetone or acetic acid can be used. The proportions of bromine and abrasive grains in the resulting polishing solution are suitably 0.1 to 5% by volume and 0.1 to 2% by weight, respectively. The method of the present invention sufficiently combines the oxidation effect of bromine and the mechanical polishing effect of alumina, and the resulting semiconductor crystal wafer has a linear or silk-like pattern on its mirror surface due to scratches. First, the edges of the wafer do not sag, and the polishing time can be shortened.

Next, the operation and effects of the method of the present invention will be explained in detail using Examples and Comparative Examples.

Example A commercially available suspension of alumina particles suspended in water (Fujimi Kenma Kogyo Co., Ltd. Type FM-4) was allowed to stand still, the top light was removed, and the resulting alumina was dried to a grain height of about 0. Obtained 3 Buddhas of alumina.

The above alumina log was suspended in 200 cc of a methyl alcohol solution containing 1% by volume of bromine to prepare a polishing liquid. Using a regular mirror polisher, attach the retaining plate to a diameter 25 side and a thickness 5 mm.
Attach a 00 French indium phosphorus wafer, place the crystal plane that should be a mirror surface on the polishing cloth, and apply the previous polishing solution to the polishing cloth.
While circulating the focus at a rate of 0 cc min, hold the retaining plate for 5 minutes. p. m. I rotated it and polished it.

At this time, the load applied to the indium phosphorus wafer is 20 female/
It was grounded. After about 2 minutes of polishing, the surface began to become glossy, and after about 10 minutes, it became a mirror surface. No scratches were observed on the resulting mirror surface, and the edges of the wafer did not sag. Comparative Example: 20cc of 47% hydrogen bromide water
In addition to 200cc of % acetic acid, add 40g of the above alumina to this.
The machine was operated in the same manner as in the example except that the polishing liquid was prepared by suspending the polishing liquid.

Claims (1)

[Claims] 1. A method for polishing indium phosphide crystals, characterized by using a polishing liquid obtained by suspending abrasive grains in a solution of bromine dissolved in an organic solvent.