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Proceedings Paper

Era of double exposure in 70 nm node DRAM cell
Author(s): Sang-Jin Kim; Joon-Soo Park; Tae-Young Kim; Byeong-Soo Kim; Gi-Sung Yeo; Seok-Hwan Oh; Sang-Gyun Woo; Han-Ku Cho; Joo-Tae Moon
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Paper Abstract

In this paper, two different methods of double exposure are proposed to improve the resolution in low k1 lithography. One is using an additional mask to complement the lack of image contrast. The other is to fix the mask and only use combinations of illumination systems to increase image contrast. By applying image assisting double exposure to asymmetry dense contact under k1=0.33, the process window can be doubled in comparison to the single exposure method. By an appropriate design of two masks, we could also minimize the image distortion from overlay shift by mixture of masks. Effective first order efficiency is defined as a new term in double exposure with complementary illumination. The larger the value is, the better the image contrast becomes. Through an experiment and simulation in k1=0.30, in double exposure with two illuminations and the same mask, that wider process window was obtained than in single exposure with optimized illumination system, and also 0.10um of DOF (Depth of Focus) was obtained under k1=0.28.

Paper Details

Date Published: 12 May 2004
PDF: 9 pages
Proc. SPIE 5754, Optical Microlithography XVIII, (12 May 2004); doi: 10.1117/12.599458
Show Author Affiliations
Sang-Jin Kim, Samsung Electronics Co., Ltd. (South Korea)
Joon-Soo Park, Samsung Electronics Co., Ltd. (South Korea)
Tae-Young Kim, Samsung Electronics Co., Ltd. (South Korea)
Byeong-Soo Kim, Samsung Electronics Co., Ltd. (South Korea)
Gi-Sung Yeo, Samsung Electronics Co., Ltd. (South Korea)
Seok-Hwan Oh, Samsung Electronics Co., Ltd. (South Korea)
Sang-Gyun Woo, Samsung Electronics Co., Ltd. (South Korea)
Han-Ku Cho, Samsung Electronics Co., Ltd. (South Korea)
Joo-Tae Moon, Samsung Electronics Co., Ltd. (South Korea)


Published in SPIE Proceedings Vol. 5754:
Optical Microlithography XVIII
Bruce W. Smith, Editor(s)

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