Metal oxide resist (MOR) EUV lithography processes for DRAM application

Shinichiro Kawakami; Tomoya Onitsuka; Yuya Kamei; Satoru Shimura; Chan Ha Park; Sang Ho Lee; Hong Goo Lee; Jae Wook Seo; Jin il Kim; Jun ho Roh; Jin Hyung Kim; Ki Lyoung Lee; Seiji Nagahara; Jeoung Yun Kim; Jang Hwan Kim; Shingo Inaba; Jong Eun Park

doi:10.1117/12.2613974

25 May 2022 Metal oxide resist (MOR) EUV lithography processes for DRAM application

Shinichiro Kawakami, Tomoya Onitsuka, Yuya Kamei, Satoru Shimura, Chan Ha Park, Sang Ho Lee, Hong Goo Lee, Jae Wook Seo, Jin il Kim, Jun ho Roh, Jin Hyung Kim, Ki Lyoung Lee, Seiji Nagahara, Jeoung Yun Kim, Jang Hwan Kim, Shingo Inaba, Jong Eun Park

Author Affiliations +

Proceedings Volume 12055, Advances in Patterning Materials and Processes XXXIX; 120550N (2022) https://doi.org/10.1117/12.2613974
Event: SPIE Advanced Lithography + Patterning, 2022, San Jose, California, United States

Conference Poster

Abstract

This paper reports the readiness of key EUV resist process technologies using Metal Oxide Resist (MOR) aiming for the DRAM application. For MOR, metal contamination reduction and CD uniformity (CDU) are the key performance requirements expected concerning post exposure bake (PEB). Based on years of experience with spin-on type Inpria MOR, we have designed a new PEB oven to achieve contamination mitigation, while keeping our high standard of CDU. The new bake oven was introduced in our coater and developer and evaluated using line/space patterns. As described in the results, exceptional CD uniformity was realized while exceeding the metal contamination specification. The new plate design also enabled a 30% reduction in dose-to-size without degradation of CDU when applying higher PEB temperature. Another challenge for the DRAM application in particular is pattern collapse as applied to pillar patterns. By optimization of several parameters, the pattern collapse margin extended the minimum CD by 13.8%. The result was achieved with a combination of SiC in place of SOG for under layer, thinner resist film thickness and a modified resist material, MOR-B. Finally, to achieve target yield performance, defectivity reduction is also an important task towards MOR application. An integrated approach is needed to realize scum free patterning because if metal residuals remain in the open space, they can cause yield-killing defects. By analyzing possible root causes of defect sources, we attempt to eliminate etch-masking scum layer present after conventional developer processing. By applying a post develop rinse including novel hardware for defect reduction, bridge defects were reduced up to 19% with new the technology.

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Shinichiro Kawakami, Tomoya Onitsuka, Yuya Kamei, Satoru Shimura, Chan Ha Park, Sang Ho Lee, Hong Goo Lee, Jae Wook Seo, Jin il Kim, Jun ho Roh, Jin Hyung Kim, Ki Lyoung Lee, Seiji Nagahara, Jeoung Yun Kim, Jang Hwan Kim, Shingo Inaba, and Jong Eun Park "Metal oxide resist (MOR) EUV lithography processes for DRAM application", Proc. SPIE 12055, Advances in Patterning Materials and Processes XXXIX, 120550N (25 May 2022); https://doi.org/10.1117/12.2613974

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