Method for preparing double-depth shallow trench isolation groove

Abstract

The invention provides a method for preparing a double-depth shallow trench isolation groove. The double-depth shallow trench isolation groove is prepared through two completely independent preparation technologies such as a logic region depth shallow trench isolation groove technology and a pixel region shallow shallow trench isolation groove technology, so that the double slope appearance of the depth shallow trench isolation groove is avoided; through the excellent filling ability characteristic of an ODL (organic dielectric layer), the filling and planarization of the depth shallow trench isolation groove can be finished; and furthermore, through the shallow depth characteristic of the shallow shallow trench isolation groove, a second photoresist layer and an organic isolation layer are used as mask layers etched by pixel region shallow shallow trench isolation (STI), so that the problem of forming stepped height difference in two STI etchings of the hard mask layers can be avoided.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for preparing double-depth shallow trench isolation grooves. Background technique [0002] The Shallow Trench Isolation (STI) process is one of the key processes in the formation of CMOS devices. With the continuous shrinking of the device size, the thickness of the photoresist is limited, but the etching depth of STI does not decrease too much, so that the photoresist It cannot meet the thickness requirement of the STI etching mask layer, so after the 130nm technology node, the silicon nitride hard mask process is widely used in the prior art for STI etching. With the further shrinking of the pattern size, after the 45nm technology node, a single ArF photoresist as a mask layer cannot meet the requirements in terms of thickness and pattern transfer quality, so amorphous carbon + silicon nitride mask etching or Three-layer composite photoresist mask etching is...

AI Technical Summary

Problems solved by technology

[0012] The purpose of the present invention is to provide a method for preparing a double-depth shallow trench isolation trench, which can avoid the double slope of the side wall of the shallow trench isolation trench in the prior art while forming a double-depth shallow trench isolation trench structure Topography and step-like height difference of the hard mask layer

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