Diffraction order control in overlay metrology: a review of the roadmap options

Mike Adel; Daniel Kandel; Vladimir Levinski; Joel Seligson; Alex Kuniavsky

doi:10.1117/12.773243

14 March 2008 Diffraction order control in overlay metrology: a review of the roadmap options

Mike Adel, Daniel Kandel, Vladimir Levinski, Joel Seligson, Alex Kuniavsky

Proceedings Volume 6922, Metrology, Inspection, and Process Control for Microlithography XXII; 692202 (2008) https://doi.org/10.1117/12.773243
Event: SPIE Advanced Lithography, 2008, San Jose, California, United States

Abstract

Resolution enhancement in advanced optical lithography will reach a new plateau of complexity at the 32 nm design rule manufacturing node. In order to circumvent the fundamental optical resolution limitations, ultra low k₁ printing processes are being adopted, which typically involve multiple exposure steps. Since alignment performance is not fundamentally limited by resolution, it is expected to yield a greater contribution to the effort to tighten lithographic error budgets. In the worst case, the positioning budget usually allocated to a single patterning step is divided between two. A concurrent emerging reality is that of high order overlay modeling and control. In tandem with multiple exposures, this trend creates great pressure to reduce scribeline target real estate per exposure. As the industry migrates away from metrology targets formed from large isolated features, the adoption of dense periodic array proxies brings improved process compatibility and information density as epitomized by the AIM target¹. These periodic structures enable a whole range of new metrology sensor architectures, both imaging and scatterometry based, that rely on the principle of diffraction order control and which are no longer aberration limited. Advanced imaging techniques remain compatible with side-by-side targets while scatterometry methods require grating-over-grating targets. In this paper, a number of different imaging and scatterometry architectures are presented and compared in terms of random errors, systematic errors and scribespace requirements. It is asserted that an optimal solution must combine the TMU peak performance capabilities of scatterometry with the cost of ownership advantages of target size and multi-layer capabilities of imaging.

Citation Download Citation

Mike Adel, Daniel Kandel, Vladimir Levinski, Joel Seligson, and Alex Kuniavsky "Diffraction order control in overlay metrology: a review of the roadmap options", Proc. SPIE 6922, Metrology, Inspection, and Process Control for Microlithography XXII, 692202 (14 March 2008); https://doi.org/10.1117/12.773243

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