Wax-free polishing method for ultrathin semiconductor wafer

Abstract

The invention provides a wax-free polishing method for an ultrathin semiconductor wafer, which comprises the following steps: (1) a gallium arsenide wafer to be polished with the diameter of D is placed on an adsorption pad mold A to be subjected to back rough polishing; the adsorption pad mold A is provided with a round hole A; the depth of the round hole A is 150-180 mu m; (2) the workpiece is placed on an adsorption pad mold B for front rough polishing; a round hole B is formed in an adsorption pad mold B; the depth of the round hole B ranges from 120 micrometers to 150 micrometers; (3) the gallium arsenide wafer processed in the step (2) is placed on an adsorption pad mold C to be subjected to back face fine polishing; the adsorption pad mold C is provided with a round hole C; the depth of the round hole C ranges from 80 micrometers to 120 micrometers; (4) placing the gallium arsenide wafer treated in the step (3) on the adsorption pad mold C for front fine polishing; and (5) washing. The wax-free polishing method for the ultrathin semiconductor wafer has the advantages that the breakage rate is lower; the percent of pass of the wax-free polishing double-polishing ultrathin gallium arsenide wafer processing technology is increased; and the production cost is reduced.

Description

technical field [0001] The invention relates to the field of semiconductor preparation, in particular to a wax-free polishing method for ultra-thin semiconductor wafers. Background technique [0002] As the second-generation semiconductor materials, gallium arsenide, germanium, etc., have shown more and more broad application prospects in the fields of mobile phones, infrared optics, and satellite communications by virtue of their superior electronic properties. However, in the production process from the growth of gallium arsenide crystal to the actual application of the finished gallium arsenide wafer, a series of complicated processing processes are required. Among them, during the polishing process of the ultra-thin gallium arsenide wafer, due to the thickness The fluctuation requirement range is narrow, generally 10-20μm; therefore, the flatness requirement is very high in the processing process, and the chip is thin, so the chipping rate is high in the processing proce...

AI Technical Summary

Problems solved by technology

[0005] (1) Because the wafer is thin, there is a high probability of debris during the process of wax absorption under vacuum conditions in the chamber;

[0006] (2) Due to the difficulty in infiltrating the supply liquid during the polishing process, dry grinding will be caused during the polishing process, and the debris rate is high;

[0007] (3) The debris rate is also high during the waxing process

[0008] (4) For double-polished wafers, it needs to be waxed and roughly polished twice. The thinner the wafer, the higher the debris rate

[0009] According to statistics, the overall breakage rate of GaAs wafers polished to 100 μm by the above-mentioned wax polishing process is as high as 40% to 70%.

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