A bilinear photoresist model is accurate, fast, and potentially reversible. Similar to other image-processing style (blur kernel) models, this model represents a transformation of an aerial image into a latent image. The key difference is the explicit recognition of the non-linearity of the process while retaining common signal processing architecture. By applying a Volterra series expansion to the reaction-diffusion functional, a high-accuracy representation of the process is obtained. Several methods for identifying the double-impulse response of the quadratic term of the series are discussed. Characterization is carried out based on the bi-harmonic signal sampling method of the Bilinear Transfer Function, the Fourier transform of the double-impulse spread function. Several photoresist systems are characterized, and strong quadratic behavior is observed for many. The resulting estimated BTF are presented, and their differences are discussed.

Date Published: 10 March 2010
PDF: 10 pages
Proc. SPIE 7640, Optical Microlithography XXIII, 76400P (10 March 2010);

Published in SPIE Proceedings Vol. 7640:
Optical Microlithography XXIII
Mircea V. Dusa; Will Conley, Editor(s)