Semiconductor device manufacturing: process – Masking – Subphotolithographic processing
Reexamination Certificate
2005-04-12
2005-04-12
Nguyen, Ha Tran (Department: 2812)
Semiconductor device manufacturing: process
Masking
Subphotolithographic processing
C438S756000, C438S757000, C438S745000
Reexamination Certificate
active
06878646
ABSTRACT:
A method of reducing the critical dimension (CD) of a hard mask by a wet etch method is described. An oxide hard mask is treated with a H2SO4/H2O2(SPM) solution followed by treatment with a NH4OH/H2O2/H2O (APM) solution to trim the CD by 0 to 20 nm. With nitride or oxynitride hard masks, a buffered HF dip is inserted prior to the SPM treatment. For oxide hard masks, the SPM solution performs the etch while APM solution assists in removing plasma etch residues. With oxynitride hard masks, the APM performs the etch while BHF and SPM solutions remove plasma etch residues. The hard mask pattern can then be transferred with a dry etch into an underlying polysilicon layer to form a gate length of less than 150 nm while controlling the CD to within 3 to 5 nm of a targeted value.
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Fang Fuxuan
Tsai Chao-Tzung
Wu Jia-Sheng
Nguyen Ha Tran
Taiwan Semiconductor Manufacturing Company
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