Full chip computational lithography for KrF multi-focal imaging (MFI) (Conference Presentation)

Will Conley; Vince Vince Plachecki; Stephen Hsu; Michael Crouse; Rongkuo Zhao; John He; Pieter Scheijgrond; Dezheng Sun; Xiaoyang Li; Dongqing Zhang; Ming-Chun Tien; Jun Ye; Rafael Howell; Chen Liu; Xiaolong Zhang; Hai Li; Zuanyi Li; Xiaobo Xie; Jing Su; Yzzer Roman

doi:10.1117/12.2585651

26 February 2021 Full chip computational lithography for KrF multi-focal imaging (MFI) (Conference Presentation)

Will Conley, Vince Vince Plachecki, Stephen Hsu, Michael Crouse, Rongkuo Zhao, John He, Pieter Scheijgrond, Dezheng Sun, Xiaoyang Li, Dongqing Zhang, Ming-Chun Tien, Jun Ye, Rafael Howell, Chen Liu, Xiaolong Zhang, Hai Li, Zuanyi Li, Xiaobo Xie, Jing Su, Yzzer Roman

Author Affiliations +

Proceedings Volume 11613, Optical Microlithography XXXIV; 116130E (2021) https://doi.org/10.1117/12.2585651
Event: SPIE Advanced Lithography, 2021, Online Only

Abstract

Over the years, lithography engineers have continued to focus on CD control, overlay and process capability to meet node requirements for yield and device performance. Previous work by Fukuda1 developed a multi-exposure technique at multi-focus positions to image contact holes with adequate DOF. Lalovic2 demonstrated a fixed 2-wavelength technique to improve DOF called RELAX. The concept of multi-focal imaging (MFI) was introduced3 demonstrating two focal positions are created that are averaged over the exposure field, this wavelength “dithering” approach which can be turned on and off, thus eliminating any potential scanner calibration issues. In this work, the application of this imaging method (1 exposure-2 focus positions) can be used in thick photoresist and high aspect ratio applications. An example of thick photoresist imaging is shown in figure 1. We demonstrate 5um line and space features in 10um of photoresist at 3 different imaging conditions. On the left, single focus imaging (SFI) at best dose and focus, the center image which is also SFI but at a defocus of +3.2um. On the right is MFI with 2 focus positions of 0 and 2.8um. Here we can see a significant improvement in the SWA linearity and image profile quality. A second example of high aspect ratio imaging using MFI is shown in figure 2. The aspect ratio of 13:1 is shown for this. The use of Tachyon KrF MFI source – mask optimization flow will be reviewed to demonstrate optimum conditions to achieve Customer required imaging to meet specific layer requirements.

Conference Presentation

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Will Conley, Vince Vince Plachecki, Stephen Hsu, Michael Crouse, Rongkuo Zhao, John He, Pieter Scheijgrond, Dezheng Sun, Xiaoyang Li, Dongqing Zhang, Ming-Chun Tien, Jun Ye, Rafael Howell, Chen Liu, Xiaolong Zhang, Hai Li, Zuanyi Li, Xiaobo Xie, Jing Su, and Yzzer Roman "Full chip computational lithography for KrF multi-focal imaging (MFI) (Conference Presentation)", Proc. SPIE 11613, Optical Microlithography XXXIV, 116130E (26 February 2021); https://doi.org/10.1117/12.2585651

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