Method for removing silicon nitride layer on patterned wafer

Abstract

The invention relates to a method for removing a silicon nitride layer on a patterned wafer. The method comprises the steps of providing a patterned wafer, wherein a silicon nitride layer to be removed and a first silicon oxide layer are exposed from the surface of the patterned wafer, providing a first control wafer, wherein the first control wafer is provided with a second silicon oxide layer and a sacrificial silicon nitride layer covering the second silicon oxide layer, placing the first control wafer into a phosphoric acid tank until the phosphoric acid tank is provided with precipitation therein, providing a second control wafer, forming a third silicon oxide layer at the surface of the second control wafer, wherein silicon-oxygen bonds in the third silicon oxide layer are not tight in connection, placing the second control wafer, on which the third silicon oxide layer is formed, into the phosphoric acid tank until the precipitation disappears, and placing the patterned wafer into the phosphoric acid tank with the precipitation being disappeared, wherein the silicon nitride layer to be removed of the patterned wafer is removed. The performance of a semiconductor device on the patterned wafer can be improved by adopting the method provided by the invention.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a method for removing a silicon nitride layer on a patterned wafer. Background technique [0002] In the fabrication of semiconductor devices, blank wafers are formed into patterned wafers. Wherein, the silicon oxide layer and the silicon nitride layer are exposed on the surface of the patterned wafer. Wherein, the silicon oxide layer can be used as a gate oxide layer and a dielectric layer of a subsequently formed semiconductor device. The silicon nitride layer can be used as a sidewall, a stress layer, a dielectric layer, etc. of a subsequently formed semiconductor device. [0003] During the process of removing the silicon nitride layer that needs to be removed in the patterned wafer, the silicon oxide layer that must remain in the patterned wafer will always be damaged, thereby affecting the performance of the subsequently formed semiconductor device. In order to improve the ...

Images