Lens heating challenges for negative tone develop layers with freeform illumination: a comparative study of experimental vs. simulated results

Scott Halle; Michael Crouse; Aiqin Jiang; Youri van Dommelen; Tim Brunner; Blandine Minghetti; Matt Colburn; Youping Zhang

doi:10.1117/12.916312

21 February 2012 Lens heating challenges for negative tone develop layers with freeform illumination: a comparative study of experimental vs. simulated results

Scott Halle, Michael Crouse, Aiqin Jiang, Youri van Dommelen, Tim Brunner, Blandine Minghetti, Matt Colburn, Youping Zhang

Author Affiliations +

Proceedings Volume 8326, Optical Microlithography XXV; 832607 (2012) https://doi.org/10.1117/12.916312
Event: SPIE Advanced Lithography, 2012, San Jose, California, United States

Abstract

Negative tone development (NTD) processes have been widely explored as a way to enhance the printability of dark field features such as contact holes and trenches. A key consequence of implementing NTD processes and subsequent tone reversal of dark field reticles is the significantly higher transmission of bright field masks and thus higher light intensity in the projection optics. This large increase in mask transmission coupled with the higher throughput requirements of multiple patterning and the use of freeform illumination created by source mask optimization creates a significant amount of lens heating induced aberrations that must be characterized and mitigated. In this paper, we examine the lens heating induced aberrations for high transmission reticles common to NTD using both simulations and experiments on a 193 immersion lithography tool. We observe a substantial amount of aberrations as described by even and odd order Zernike drifts during the course of a wafer exposure lot. These Zernike drifts per lot are demonstrated to have the following lithographic effects: critical dimension shifts, pitch dependent best focus shifts and image placement errors between coarse and fine patterned features. Lastly, mitigation strategies are demonstrated using various controllers and lens manipulators, including FlexWave with full Zernike control up to Z64, to substantially reduce the lens heating effects observed on-wafer.

Citation Download Citation

Scott Halle, Michael Crouse, Aiqin Jiang, Youri van Dommelen, Tim Brunner, Blandine Minghetti, Matt Colburn, and Youping Zhang "Lens heating challenges for negative tone develop layers with freeform illumination: a comparative study of experimental vs. simulated results", Proc. SPIE 8326, Optical Microlithography XXV, 832607 (21 February 2012); https://doi.org/10.1117/12.916312

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