Wafer Preparation Method for Improving Wafer Strength and Backside Metal-Silicon Adhesion Strength

Abstract

The invention provides a wafer preparation method capable of enhancing wafer strength and back metal-silicon adhesion strength, relating to the technical field of semiconductor wafers. The invention solves the problems of metal shedding and the like caused by overlarge wafer back damaged layer, insufficient wafer strength, high fragment rate and poor back metal adhesion strength in the existing process. The method comprises the following steps: carrying out back sandblasting on a thinned chip to obtain a chip to be etched; putting the obtained chip into an acid tank, carrying out back etching by using a concentrated acid etching solution, flushing with water, and carrying out centrifugal drying to obtain the etched chip, wherein the concentrated acid etching solution is composed of nitric acid, glacial acetic acid, water and HF in a volume ratio of 16000:800:8000:2000; carrying out back metal deposition on the chip; and carrying out chip back metal evaporation by using an evaporation table. The wafer is composed of the following metal layers: V with the thickness of 400 angstroms, Ni with the thickness of 8000 angstroms and Ag with the thickness of 12000 angstroms. The method relieves the problem of insufficient strength of the chip subjected to thinning etching, and enhances the adhesion property of the metals.

Description

technical field [0001] The invention relates to the technical field of semiconductor wafers, in particular to a wafer manufacturing method for improving the strength of the wafer and the adhesion strength between back metal and silicon. Background technique [0002] At present, the production method of backside thinning + backside corrosion is generally used in the industry to manufacture semiconductor chips. The disadvantages of this method are as follows: [0003] After corrosion, the damage layer on the back side is too large, the strength of the wafer is insufficient, the fragmentation rate is high, and the metal adhesion on the back side is poor, which leads to the abnormal problem of metal loss, which is not conducive to mass production. Contents of the invention [0004] The present invention solves the problems of excessively large damaged layer on the back of the crystal surface, insufficient wafer strength, high fragmentation rate and poor adhesion strength of th...

AI Technical Summary

Problems solved by technology

[0004] The present invention solves the problems of excessively large damaged layer on the back of the crystal surface, insufficient wafer strength, high fragmentation rate and poor adhesion strength of the metal on the back, which leads to metal loss in the existing method, and provides a method for improving the strength of the wafer and the strength of the back metal and silicon. Wafer Preparation Method for Adhesion Strength

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