Share Email Print

Proceedings Paper

Ultimate 2D resolution printing with negative tone development
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

The printing of contact holes using positive tone development typically requires the interference of more than the 0th and 1st diffracted orders. In the 2d case and cQuad illumination in a positive tone process, if (0,0), (±1,0), and (0,±1) are exclusively present, the relevant contrast for imaging can in the best case not rise above 0.33, which is typically insufficient for a good process window. And this maximum value can only be achieved if the (0,0) and (±1,0) orders are matched to give a perfect sine wave of perfect contrast in y while the (0,0) and (0,±1) orders yield perfect contrast in x. In reality, the contrast is quite a bit lower. On the other hand, for negative tone development we are interested in the minima of the intensity–the dark locations in the image–and if we can manage to reduce the intensity in the minima we can achieve a high contrast image. Through a choice of RET and illumination, we manage to achieve a resolution for contact holes in 2d at k1 values that can otherwise be achieved only for 1d imaging.

Earlier work has been done on double exposures that exposed in the same resist a horizontal grating with x-dipoles and subsequently a vertical grating with y dipoles, without intermediate process steps. This yielded a high contrast image in resist at k1 <0.3.1 We show that an equivalent result can be achieved in a single exposure with a single mask, at admittedly high dose. We investigate the process parameters and the related mask tolerances, and find a non-intuitive result for the mask pattern that yields an optimized image at given mask specifications. Finally, we investigate the extension of this technique to EUV through simulations and experiments.

Paper Details

Date Published: 15 March 2016
PDF: 20 pages
Proc. SPIE 9780, Optical Microlithography XXIX, 97800E (15 March 2016); doi: 10.1117/12.2219765
Show Author Affiliations
Martin Burkhardt, IBM Research (United States)
Yongan Xu, IBM Research (United States)
Hsinyu Tsai, IBM Research (United States)
Alexander Tritchkov, Mentor Graphics Corp. (United States)
Jörg Mellmann, Mentor Graphics Corp. (United States)

Published in SPIE Proceedings Vol. 9780:
Optical Microlithography XXIX
Andreas Erdmann; Jongwook Kye, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?