Method for eliminating wafer surface defect in wet etching

Abstract

The invention provides a method for eliminating a wafer surface defect in wet etching. A control wafer is used for replacing a processing wafer to manufacture a proper silicide-contained phosphoric acid solution, thereby reducing the production cost. A silicon nitride film of the control wafer reacts with the phosphoric acid solution to generate the silicide for inhibiting silicon dioxide corrosion, so that a problem of sound filed cost increasing because of adding the silicide into the phosphoric acid solution independently can be effectively solved. Impurities attached to the surface of the control wafer after silicon nitride corrosion are removed by using a mixed solution with phosphoric acid and sulfuric acid in a proper ratio; and impurities on the surface of the processing wafer are also removed by using a mixed solution with phosphoric acid and sulfuric acid in a same proper ratio, so that the product yield is effectively reduced under the circumstance that no defect exist on the wafer surface.

Description

technical field [0001] The invention relates to a semiconductor preparation method, in particular to a method for removing surface defects of wafers in wet etching. Background technique [0002] Silicon nitride is a dielectric material widely used in wafer manufacturing. The silicon nitride film is typically formed on a semiconductor substrate, generally used as a barrier layer for etching silicon dioxide in a wafer, and formed on the upper surface of the silicon dioxide layer. In the wet etching process, phosphoric acid is often used to etch or etch the silicon nitride barrier layer. During the etching process, a large number of wafers are usually placed in the phosphoric acid solution at the same time, because silicon nitride and silicon dioxide in the phosphoric acid solution have different etching rates (etching selectivity), that is, the same time Internal phosphoric acid etches silicon nitride and silicon dioxide at different rates. [0003] Factors that affect the ...

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Problems solved by technology

[0007] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for removing defects on the wafer surface in wet etching, which is used to solve the cost increase caused by the addition of silicon substances in the phosphoric acid solution in the prior art , Impurities formed after silicon nitride is etched are likely to cause defects on the wafer and have to reduce production efficiency in order to reduce wafer defects

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