New double exposure technique without alternating phase-shift mask

Tomohiko Yamamoto; Teruyoshi Yao; Hiroki Futatsuya; Tatsuo Chijimatsu; Satoru Asai

doi:10.1117/12.711956

26 March 2007 New double exposure technique without alternating phase-shift mask

Tomohiko Yamamoto, Teruyoshi Yao, Hiroki Futatsuya, Tatsuo Chijimatsu, Satoru Asai

Proceedings Volume 6520, Optical Microlithography XX; 65202P (2007) https://doi.org/10.1117/12.711956
Event: SPIE Advanced Lithography, 2007, San Jose, California, United States

Abstract

The double exposure technique using alternating phase shift mask (alt-PSM) has been proposed and it is well used for the gate layer of the high performance logic devices as strong resolution enhancement technology (RET). This technique has advantage that the fine resist profile is obtained on wafer with extensive process margin. However, this double exposure technique is very expensive because of the alt-PSM cost. This time, the new double exposure technique without alt-PSM is developed for gate layer of 45 nm node logic devices. In this new double exposure method, attenuated phase shift mask (att-PSM) or binary mask (BIM) is used with dipole illumination. It is thought that this new double exposure method is effective for random logic devices which have various pattern pitches by the optimization of dipole illumination condition and pattern placement. Firstly, the optical contrast and depth of focus (DOF) is calculated. From these results, dipole illumination condition is optimized. It is found that DOF of new double exposure method is wider than that of conventional method. In addition, mask pattern is optimized to obtain wide process margin. For dense pattern, mask biasing is effective and optimization of shifter width is effective for isolated pattern. Furthermore, it is found that assist pattern is very effective for isolated pattern. From experimental results, it is proved that new double exposure method have wider process margin than that of conventional one. The strong design for manufacturing (DFM) rule that required the severe line width control is placed at single direction is proposed to realize the new double exposure method. Finally, it is found that the lithographic performance of new double exposure method has same level as conventional method with alt-PSM for gate layer of 45 nm logic devices.

Citation Download Citation

Tomohiko Yamamoto, Teruyoshi Yao, Hiroki Futatsuya, Tatsuo Chijimatsu, and Satoru Asai "New double exposure technique without alternating phase-shift mask", Proc. SPIE 6520, Optical Microlithography XX, 65202P (26 March 2007); https://doi.org/10.1117/12.711956

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