Overlay accuracy with respect to device scaling

Philippe Leray; David Laidler; Shaunee Cheng

doi:10.1117/12.918017

4 April 2012 Overlay accuracy with respect to device scaling

Philippe Leray, David Laidler, Shaunee Cheng

Proceedings Volume 8324, Metrology, Inspection, and Process Control for Microlithography XXVI; 832409 (2012) https://doi.org/10.1117/12.918017
Event: SPIE Advanced Lithography, 2012, San Jose, California, United States

Abstract

Overlay metrology performance is usually reported as repeatability, matching between tools or optics aberrations distorting the measurement (Tool induced shift or TIS). Over the last few years, improvement of these metrics by the tool suppliers has been impressive. But, what about accuracy? Using different target types, we have already reported small differences in the mean value as well as fingerprint [1]. These differences make the correctables questionable. Which target is correct and therefore which translation, scaling etc. values should be fed back to the scanner? In this paper we investigate the sources of these differences, using several approaches. First, we measure the response of different targets to offsets programmed in a test vehicle. Second, we check the response of the same overlay targets to overlay errors programmed into the scanner. We compare overlay target designs; what is the contribution of the size of the features that make up the target? We use different overlay measurement techniques; is DBO (Diffraction Based Overlay) more accurate than IBO (Image Based Overlay)? We measure overlay on several stacks; what is the stack contribution to inaccuracy? In conclusion, we offer an explanation for the observed differences and propose a solution to reduce them.

Citation Download Citation

Philippe Leray, David Laidler, and Shaunee Cheng "Overlay accuracy with respect to device scaling", Proc. SPIE 8324, Metrology, Inspection, and Process Control for Microlithography XXVI, 832409 (4 April 2012); https://doi.org/10.1117/12.918017

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