Numerical and experimental studies of pellicle-induced photomask distortions

Eric P. Cotte; Roxann L. Engelstad; Edward G. Lovell; Yuri M. Shkel; Florence O. Eschbach; Emily Y. Shu; Daniel Tanzil; Rebecca Calhoun

doi:10.1117/12.458346

11 March 2002 Numerical and experimental studies of pellicle-induced photomask distortions

Eric P. Cotte, Roxann L. Engelstad, Edward G. Lovell, Yuri M. Shkel, Florence O. Eschbach, Emily Y. Shu, Daniel Tanzil, Rebecca Calhoun

Author Affiliations +

Proceedings Volume 4562, 21st Annual BACUS Symposium on Photomask Technology; (2002) https://doi.org/10.1117/12.458346
Event: Photomask 2001, 2001, Monterey, CA, United States

Abstract

Meeting the stringent error budget of 157-nm lithography for manufacturing devices in the sub-100 nm regime requires that all mask-related distortions be minimized, corrected, or eliminated. Sources include the pellicle system, which has been previously identified as a potential cause of image placement error. To characterize pellicle-induced distortions, finite element (FE) models have been developed to simulate system fabrication, including soft pellicles as well as prototype fused silica (hard) pellicles. The main sources of distortions are: (a) temperature variations, (b) initially distorted components, and (c) sag-induced refraction. Temperature variations are an issue if pellicle mounting and exposure take place at different temperatures. Sources of attachment-induced distortions include the initial frame curvature, initial reticle shape, attachment method (mounting tools-induced), frame and gasket materials, and the hard pellicle bow. These attachment-induced distortions were modeled using experimentally measured values of Young's modulus for adhesive gaskets. Refraction aberration is an issue with bowed hard pellicles which act as optical elements and induce image degradation. These effects were assessed and found to be significant. Results from the experiments and comprehensive FE simulations have characterized the relative importance of the principal sources of pellicle-induced photomask distortions for 157-nm lithography.

Citation Download Citation

Eric P. Cotte, Roxann L. Engelstad, Edward G. Lovell, Yuri M. Shkel, Florence O. Eschbach, Emily Y. Shu, Daniel Tanzil, and Rebecca Calhoun "Numerical and experimental studies of pellicle-induced photomask distortions", Proc. SPIE 4562, 21st Annual BACUS Symposium on Photomask Technology, (11 March 2002); https://doi.org/10.1117/12.458346

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