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Proceedings Paper

Dissolution Rate Modifying Chemistry: Interaction of Base-soluble and Base-insoluble Non-actinic Dyes With Novolak Polymers and Novolak-based Positive Photoresists
Author(s): George J. Cernigliaro; Michael F. Cronin; Thomas A. Fisher; Marjorie E. Perkins; Pamela Turci
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Paper Abstract

The use of controlled absorption by the addition of organic dyes to photoresists has improved notching control over topography on reflective substrates. However, the majority of dyes commonly used have a side effect of significant photospeed loss. Earlier work by Bohland et all has shown the dissolution effect of either coumarin 6 or coumarin 314 dye in photoresist to play a greater role in changing energy required to expose the resist than the optical effects of the dyes. Curcumin dye was found to minimize photospeed loss in novolak-based positive photoresist while maintaining control of reflective notching. Preliminary base solubility investigations of curcumin and coumarin 314 revealed striking differences between the two dyes. Curcumin is freely soluble in metal ion bearing developers as well as in metal ion free developers; coumarin 314 is sparingly soluble at best in both developer types. Curcumin owes its absorption at 436 nm to extended conjugation of its enolic tautomer, which is more acidic than its keto counterpart. This increased acidity is conjectured to be the main cause of curcumin's enhanced solubility in base, as compared to coumarin 314. The effect of these differences on photoresist lithographic performance is the subject of this paper. Using Bohland's methodology, the Dill optical and dissolution rate constants were combined in turn to partition the optical and the dissolution contributions of both dyes to the resulting simulated image. SAMPLE and DRM-PROSIM simulations were conducted. Dissolution rates of dyed, unsensitized polymers were measured as a function of both dye loading and type. Additionally, unexposed dissolution rates of both curcumin- and coumarin 314-dyed Shipley Microposit® S1400-31TM photoresists were measured as a function of their respective dye loadings.

Paper Details

Date Published: 30 January 1989
PDF: 11 pages
Proc. SPIE 1086, Advances in Resist Technology and Processing VI, (30 January 1989); doi: 10.1117/12.953023
Show Author Affiliations
George J. Cernigliaro, Shipley Company Incorporated (United States)
Michael F. Cronin, Shipley Company Incorporated (United States)
Thomas A. Fisher, Shipley Company Incorporated (United States)
Marjorie E. Perkins, Shipley Company Incorporated (United States)
Pamela Turci, Shipley Company Incorporated (United States)

Published in SPIE Proceedings Vol. 1086:
Advances in Resist Technology and Processing VI
Elsa Reichmanis, Editor(s)

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