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Proceedings Paper

Comparison of methods for acid quantification: impact of resist components on acid-generating efficiency
Author(s): James F. Cameron; Leslie Fradkin; Kathryn Moore; Gerd Pohlers
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Paper Abstract

Chemically amplified deep UV (CA-DUV) positive resists are the enabling materials for manufacture of devices at and below 0.18 micrometer design rules in the semiconductor industry. CA-DUV resists are typically based on a combination of an acid labile polymer and a photoacid generator (PAG). Upon UV exposure, a catalytic amount of a strong Bronsted acid is released and is subsequently used in a post-exposure bake step to deprotect the acid labile polymer. Deprotection transforms the acid labile polymer into a base soluble polymer and ultimately enables positive tone image development in dilute aqueous base. As CA-DUV resist systems continue to mature and are used in increasingly demanding situations, it is critical to develop a fundamental understanding of how robust these materials are. One of the most important factors to quantify is how much acid is photogenerated in these systems at key exposure doses. For the purpose of quantifying photoacid generation several methods have been devised. These include spectrophotometric methods, ion conductivity methods and most recently an acid-base type titration similar to the standard addition method. This paper compares many of these techniques. First, comparisons between the most commonly used acid sensitive dye, tetrabromophenol blue sodium salt (TBPB) and a less common acid sensitive dye, Rhodamine B base (RB) are made in several resist systems. Second, the novel acid-base type titration based on the standard addition method is compared to the spectrophotometric titration method. During these studies, the make up of the resist system is probed as follows: the photoacid generator and resist additives are varied to understand the impact of each of these resist components on the acid generation process.

Paper Details

Date Published: 23 June 2000
PDF: 14 pages
Proc. SPIE 3999, Advances in Resist Technology and Processing XVII, (23 June 2000); doi: 10.1117/12.388302
Show Author Affiliations
James F. Cameron, Shipley Co., Inc. (United States)
Leslie Fradkin, Shipley Co., Inc. (United States)
Kathryn Moore, Shipley Co., Inc. (United States)
Gerd Pohlers, Shipley Co., Inc. (United States)

Published in SPIE Proceedings Vol. 3999:
Advances in Resist Technology and Processing XVII
Francis M. Houlihan, Editor(s)

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