Understanding the forbidden pitch phenomenon and assist feature placement

Xuelong Shi; Stephen Hsu; J. Fung Chen; Chungwei Michael Hsu; Robert John Socha; Mircea V. Dusa

doi:10.1117/12.473427

16 July 2002 Understanding the forbidden pitch phenomenon and assist feature placement

Xuelong Shi, Stephen Hsu, J. Fung Chen, Chungwei Michael Hsu, Robert John Socha, Mircea V. Dusa

Proceedings Volume 4689, Metrology, Inspection, and Process Control for Microlithography XVI; (2002) https://doi.org/10.1117/12.473427
Event: SPIE's 27th Annual International Symposium on Microlithography, 2002, Santa Clara, California, United States

Abstract

Optical proximity effect is a well-known phenomenon in photolithography. Such an effect results from the structural interaction between the main feature and the neighboring features. Recent observations have shown that such structural interactions not only affect the critical dimension of the main feature at the image plane, but also the exposure latitude of the main feature. In this paper, it has been shown that the variation of the critical dimension as well as the exposure latitude of the main feature is a direct consequence of light field interference between the main feature and the neighboring features. Depending on the phase of the field produced by the neighboring features, the main feature exposure latitude can be improved by constructive light field interference, or degraded by destructive light field interference. The phase of the field produced by the neighboring features can be shown to be dependent on the pitch as well as the illumination angle. For a given illumination, the forbidden pitch lies in the location where the field produced by the neighboring features interferes with the field of the main feature destructively. The theoretical analysis given here offers the tool to map out the forbidden pitch locations for any feature size and illumination conditions. More importantly, it provides the theoretical ground for illumination design in order to suppress the forbidden pitch phenomenon, and for scattering bar placement to achieve optimal performance as well.

Citation Download Citation

Xuelong Shi, Stephen Hsu, J. Fung Chen, Chungwei Michael Hsu, Robert John Socha, and Mircea V. Dusa "Understanding the forbidden pitch phenomenon and assist feature placement", Proc. SPIE 4689, Metrology, Inspection, and Process Control for Microlithography XVI, (16 July 2002); https://doi.org/10.1117/12.473427

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available