Model based OPC is critical for mask design employing current design rules. Models based on the aerial image assume resist response will generally follow behavior predicted by diffractive optics, however, some classes of resist introduce non-optical resist response. It is critical to understand the proximity behavior of these resists in order to accurately manufacture lithographic masks. In this paper, we present modeling and experimental results for a class of resist systems exhibiting a strong non-optical resist response; reversed bias in nested versus isolated space pattern dimension. The behavior is ascribed to a secondary source of proximity originating from heat absorbed during PEB within the exposed region, which produces a non-uniform, pattern dependent, effective PEB temperature. A continuum PEB model employing a combined mass and energy balance is developed as well as experimental methods to determine the parameters in the model. The resulting calibrated model reproduces the degree of proximity bias measured with SEM for a variety of process conditions. Both proximity correction and characterization of k1 performance for the resist system are discussed.

Date Published: 14 May 2004
PDF: 5 pages
Proc. SPIE 5376, Advances in Resist Technology and Processing XXI, (14 May 2004); doi: 10.1117/12.537701

Published in SPIE Proceedings Vol. 5376:
Advances in Resist Technology and Processing XXI
John L. Sturtevant, Editor(s)