Method for eliminating silicon substrate defect in STI process

Abstract

The invention provides a method for eliminating a silicon substrate defect in the STI process. The method includes the following steps that a silicon substrate is provided and is sequentially covered with an oxide layer and a silicon nitride layer, wherein the silicon substrate has the defect; the silicon nitride layer is etched until the surface of the oxide layer is exposed, and then a first trough is formed; the oxide layer is etched along the first trough until the silicon substrate is exposed, and then a second trough is formed; the silicon substrate is etched along the first trough and the second trough until the defect is exposed, and then a third trough is formed; the exposed defect is etched along the first trough, the second trough and the third trough and is eliminated; the silicon substrate is etched along the first trough, the second trough and the third trough, and finally etching on an STI area is completed. According to the method, the defect in the silicon substrate is etched independently, so a defect is prevented from being formed in the isolation trough, the electricity leakage phenomenon in the STI process is lightened, and an isolation effect meeting requirements can be achieved.

Description

technical field [0001] The invention relates to a semiconductor manufacturing process, in particular to a method for eliminating silicon base defects in the shallow trench isolation process. Background technique [0002] With the continuous development of integrated circuit manufacturing technology, semiconductor process technology has entered the deep sub-micron era, chip integration has continued to increase, and the size of components in the chip has therefore continued to shrink. However, no matter how the component size is reduced, each component in the chip must still have proper insulation or isolation to ensure good component performance. When the characteristic line width of components shrinks below 0.25 microns or even enters the nanometer stage, the traditional intrinsic oxidation isolation technology (LOCOS) is replaced by shallow trench isolation technology (STI) because it cannot meet the requirements of device electrical characteristics and small size. STI te...

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Problems solved by technology

[0008] In view of the above-mentioned shortcoming of the prior art, the object of the present invention is to provide a method for eliminating the silicon substrate defect in the shallow trench isolation process, which is used to solve the taper defect in the shallow trench isolation etching process in the prior art ( Cone defect), thus solving the leakage phenomenon in the shallow trench isolation process

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