100 nm half–pitch double exposure KrF lithography using binary masks

S. Geisler; J. Bauer; U. Haak; D. Stolarek; K. Schulz; H. Wolf; W. Meier; M. Trojahn; E. Matthus

doi:10.1117/12.771333

11 April 2008 100 nm half-pitch double exposure KrF lithography using binary masks

S. Geisler, J. Bauer, U. Haak, D. Stolarek, K. Schulz, H. Wolf, W. Meier, M. Trojahn, E. Matthus

Proceedings Volume 6924, Optical Microlithography XXI; 69241Z (2008) https://doi.org/10.1117/12.771333
Event: SPIE Advanced Lithography, 2008, San Jose, California, United States

Abstract

In this paper we investigate the process margin for the 100nm half - pitch double exposure KrF lithography using binary masks for different illumination settings. The application of Double Exposure Lithography (DEL) would enlarge the capability of 248 nm exposure technique to smaller pitch e.g. for the integration of dedicated layers into 0.13 μm BiCMOS with critical dimension (CD) requirements exceeding the standard 248 nm lithography specification. The DEL was carried out with a KrF Scanner (Nikon S207D, NA_Lens = 0.82) for a critical dimension (CD) of 100nm half pitch. The chemical amplified positive resists SL4800 or UV2000 (Rohm & Haas) with a thickness of 325nm were coated on a 70 nm AR10L (Rohm & Haas) bottom anti-reflective coating (BARC). With a single exposure and using binary masks it is not possible to resolve 100nm lines with a pitch of 200 nm, due to the refraction and the resolution limit. First we investigated the effect of focus variation. It is shown that the focus difference of 1st and 2nd exposure is one critical parameter of the DEL. This requires a good focus repeatability of the scanner. The depth of focus (DOF) of 360 nm with the coherence parameter σ = 0.4 was achieved for DEL with SL4800 resist. The influence of the better resist resolution of UV2000 on the process window will be shown (DOF = 460 nm). If we change the focus of one of the exposures the CD and DOF performance of spaces is reduced with simultaneous line position changing. Second we investigated the effect of different illumination shapes and settings. The results for conventional illumination with different values for σ and annular illumination with σ_inner = 0.57 and σ_outer = 0.85 will be shown. In summary, the results show that DEL has the potential to be a practical lithography enhancement method for device fabrication using high NA KrF tool generation.

Citation Download Citation

S. Geisler, J. Bauer, U. Haak, D. Stolarek, K. Schulz, H. Wolf, W. Meier, M. Trojahn, and E. Matthus "100 nm half-pitch double exposure KrF lithography using binary masks", Proc. SPIE 6924, Optical Microlithography XXI, 69241Z (11 April 2008); https://doi.org/10.1117/12.771333

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