Forbidden pitch improvement using modified illumination in lithography

被引：11

作者：

Ling, M. L. ^{[1
]}

Tay, C. J. ^{[1
]}

Quan, C. ^{[1
]}

Chua, G. S. ^{[2
]}

Lin, Q. ^{[2
]}

机构：

[1] Natl Univ Singapore, Dept Mech Engn, Singapore 117576, Singapore

[2] Chartered Semicond Mfg Ltd, Singapore 738406, Singapore

来源：

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B | 2009年 / 27卷 / 01期

关键词：

D O I：

10.1116/1.3054286

中图分类号：

TM [电工技术]; TN [电子技术、通信技术];

学科分类号：

0808 ; 0809 ;

摘要：

In lithography, forbidden pitch refers to pitch that suffers degradation in the process window due to the application of off-axis illumination (OAI). Destructive light field interference of diffracted light from a mask at forbidden pitch causes reduction in image contrast and depth of focus (DOF) and limits the pitch range to be patterned. In this paper, a modification to conventional OAI shape is proposed to minimize the effect of forbidden pitch. The modification is based on the interaction of illumination source with pattern density. The modified source employs double annular illumination. Simulation is carried out to investigate the effect of the modified source for one dimensional line and space pattern with a pitch varying from 130 to 500 nm. Results shows that the maximum critical dimension fluctuation is around 3% compared to 13% in conventional annular illumination. Furthermore, the degradation in DOF is within 21% of DOF compared to 49% in conventional annular illumination. (C) 2009 American Vacuum Society. [DOI: 10.1116/1.3054286]

引用

页码：85 / 91

页数：7

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