Shanghai Huali Microelectronics Corporation

Qiyan Feng

Yu Ren

Yukun Lv

Jian Ding

Jin Xa Xu

Hsusheng Chang

Peng Liu

Xusheng Zhang

The invention disclosed a method for forming high aspect ratio patterning structure. Firstly, forming a dielectric film ashing stop layer, a first photoresist layer, a first hard mask layer and a second photoresist layer on a semiconductor substrate in turn. A second hard mask layer having a high etch selectivity ratio with the first photoresist layer is formed on top surface and sidewall of the pattern by utilizing a low temperature chemical vapor deposition process, which can be a protect for the pattern sidewall during the later etching process of the first photoresist layer. So, the cone-shaped or the bowling-shaped photoresist morphology caused by plasma bombardment can be avoided. Therefore, the problems of the insufficient of selectivity ratio, burrs at the edge of the pattern and larger critical dimension can be solved, and the implanted ions can be well distributed according to the design of the device.

Method for forming high aspect ratio patterning structure

The present invention provides a method for controlling a critical dimension of shallow trench isolations in a STI etch process, comprises the following steps: before the STI etch process, pre-establishing a mapping relation between a post-etch and pre-etch critical dimension difference of a BARC layer and a thickness of the BARC layer; and during the STI etch process after coating the BARC layer, measuring the thickness of the BARC layer and determining a trimming time for a hard mask layer according to a critical dimension difference corresponding to the measured thickness in the mapping relation and a critical dimension of a photoresist pattern, then performing a trimming process for the hard mask layer lasting the trimming time to make a critical dimension of the hard mask layer equal to a required critical dimension of an active area, and etching a substrate to form shallow trenches with a predetermined critical dimension.

Method for establishing mapping relation in STI etch and controlling critical dimension of STI

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Shanghai, China

Qiyan Feng