Pattern wiggling investigation of self-aligned double patterning for 2x nm node NAND Flash and beyond

Lin, Y. M.; Chen, Chun‐Chi; Li, Chia‐Yu; Wang, Zih-Song; Chen, Ching-Hua

doi:10.1117/12.2010761

Cited by 6 publications

(1 citation statement)

References 4 publications

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“…A thickness-limited photoresist (PR) and a poor dry etch HM are challenging for these requirements. The thinner PRs will result in pattern bending or collapse-wiggling in the etch process [7][8][9]. In recent years, amorphous carbon hard masks (ACHM) have been used in semiconductor device fabrication, replacing the conventional SiO 2 or Si 3 N 4 HM due to its robust film properties such as high transparency, high etch selectivity, high durability for plasma Asher and easy elimination by oxygen (O 2 ) plasma [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Process Optimization of Amorphous Carbon Hard Mask in Advanced 3D-NAND Flash Memory Applications

2021

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Amorphous carbon hard mask (ACHM) films are widely used as etching hard masks in 3D-NAND flash memory, which has put forward higher requirements in the film deposition rate, film transparency, uniformity, and selective etching. In this work, the ACHM film processing is engineered and optimized by comparatively studying acetylene (C2H2) and propylene (C3H6) as carbon sources at the different temperatures of 300 °C, 350 °C and 400 °C. By increasing the deposition temperature, the deposition rate, non-uniformity, and dry etch rate of ACHM are improved at the penalty of a slightly increased extinction coefficient of the film, due to lower incorporation of hydrocarbon reactants absorbed into film at higher temperatures. However, the Fourier transformation infrared (FTIR) spectrum intensity is decreased with the increase of the deposition temperature. The lower dry etch rate of ACHM is achieved by using C3H6 as a carbon source deposited at 400 °C. The best dry etch selective ratio values are also achieved with 10.9 and 9.5 for SiO2 and SiN, respectively. These experimental results can be very promising in the advancement of etching process in 3D-NAND applications.

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