Improving focus performance at litho using diffraction-based focus metrology, novel calibration methods, interface, and control loop

Jiarui Hu; Y. L. Chen; K. H. Chen; Brian Lee; Frankie Tsai; C. M. Ke; C. H. Liao; Desmond Ngo; Benny Gosali; Robin Tijssen; Vincent Huang; Ward Tu; Marc Noot; Maryana Escalante Marun; Christian Leewis; Carlo Luijten; Frank Staals; Martijn Van Veen; Francois Furthner; Stuart Young; Kaustuve Bhattacharyya

doi:10.1117/12.2220373

8 March 2016 Improving focus performance at litho using diffraction-based focus metrology, novel calibration methods, interface, and control loop

Jiarui Hu, Y. L. Chen, K. H. Chen, Brian Lee, Frankie Tsai, C. M. Ke, C. H. Liao, Desmond Ngo, Benny Gosali, Robin Tijssen, Vincent Huang, Ward Tu, Marc Noot, Maryana Escalante Marun, Christian Leewis, Carlo Luijten, Frank Staals, Martijn Van Veen, Francois Furthner, Stuart Young, Kaustuve Bhattacharyya

Author Affiliations +

Proceedings Volume 9778, Metrology, Inspection, and Process Control for Microlithography XXX; 977829 (2016) https://doi.org/10.1117/12.2220373
Event: SPIE Advanced Lithography, 2016, San Jose, California, United States

Abstract

In advanced optical lithography the requirements of focus control continues to tighten. Usable depth of focus (DoF) is already quite low due to typical sources of focus errors, such as topography, wafer warpage and the thickness of photoresist. And now the usable DoF is further decreased by hotspots (design and imaging hotspots). All these have put extra challenges to improve focus metrology, scanner focus stability calibrations and on-product correction mechanisms.

Asymmetric focus targets are developed to address robustness in focus measurements using diffraction-based focus (DBF and μDBF) metrology. A new layout specific calibration methodology is introduced for baseline focus setup and control in order to improve scanner focus uniformity and stability using the measurements of the above mentioned asymmetric targets. A similar metrology is also used for on product focus measurements. Moreover, a few novel alternative methods are also investigated for on-product focus measurements.

Data shows good correlation between DBF and process on record (POR) method using traditional FEM. The new focus calibration demonstrated robustness, stability and speed. This technical publication will report the data from all the above activities including results from various product layers.

Citation Download Citation

Jiarui Hu, Y. L. Chen, K. H. Chen, Brian Lee, Frankie Tsai, C. M. Ke, C. H. Liao, Desmond Ngo, Benny Gosali, Robin Tijssen, Vincent Huang, Ward Tu, Marc Noot, Maryana Escalante Marun, Christian Leewis, Carlo Luijten, Frank Staals, Martijn Van Veen, Francois Furthner, Stuart Young, and Kaustuve Bhattacharyya "Improving focus performance at litho using diffraction-based focus metrology, novel calibration methods, interface, and control loop", Proc. SPIE 9778, Metrology, Inspection, and Process Control for Microlithography XXX, 977829 (8 March 2016); https://doi.org/10.1117/12.2220373

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