Study of shallow trench isolation dry etching process using oxide hard mask and KrF photo-resist in 90 nm stand-alone flash device

Eunsang Cho; Mingon Lee; Dongwon Shin; Sangil Hwang; Sangwook Ryu; Kanghyun Lee

doi:10.1117/12.773264

26 March 2008 Study of shallow trench isolation dry etching process using oxide hard mask and KrF photo-resist in 90 nm stand-alone flash device

Eunsang Cho, Mingon Lee, Dongwon Shin, Sangil Hwang, Sangwook Ryu, Kanghyun Lee

Author Affiliations +

Proceedings Volume 6923, Advances in Resist Materials and Processing Technology XXV; 69233V (2008) https://doi.org/10.1117/12.773264
Event: SPIE Advanced Lithography, 2008, San Jose, California, United States

Abstract

We investigated that Shallow Trench Isolation (STI) dry etching process using SiO2 hard-mask and KrF photo-resist in 90nm stand-alone flash device. As shrinkage of design rule, the thickness of photo-resist is reduced because of guarantee for process margin in photolithographic process, but the etch process margin is smaller. For the reason, the hard-mask system for etch is needed. Generally, the STI dry etching process is composed of two or three steps, such as the ARC etch, the hard-mask etch, and the Si etch. In order to etch multi-stacked layer (ARC, Oxide hard-mask (SiO2), Si₃N₄ as CMP stopping layer, and Si), we have controlled the parameters of etching (plasma power, gas, and pressure). In the SiO₂ hard-mask and Si₃N₄ layer etching process, we use a mixture chemistry of CF₄, CHF₃, O₂, and Ar and get an optimized condition for the multi-layer system. The SiO₂ layer is role of mask for Si layer because the selectivity between SiO₂ and Si is superior to others. Finally, we get a good horizontal and vertical profile of STI by using a mixture chemistry of Cl₂, HBr, and O₂.

Citation Download Citation

Eunsang Cho, Mingon Lee, Dongwon Shin, Sangil Hwang, Sangwook Ryu, and Kanghyun Lee "Study of shallow trench isolation dry etching process using oxide hard mask and KrF photo-resist in 90 nm stand-alone flash device", Proc. SPIE 6923, Advances in Resist Materials and Processing Technology XXV, 69233V (26 March 2008); https://doi.org/10.1117/12.773264

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