The onium salt photoacid generators that were introduced by Professor James Crivello have been used in a wide range of applications. For nearly three decades, the microelectronics industry has exploited and adapted these materials for use in the design of the high sensitivity, high resolution, “chemically amplified” photoresists. That imaging chemistry depends on an acid catalyzed thermolysis reaction that modifies the solubility of a polymer and the high sensitivity of the systems derives from diffusion of the catalyst. This diffusion is critical to the gain in the system but the mass transport that is responsible for the gain is not excluded from regions of the film that were never exposed to the imaging radiation. Diffusion into the unexposed regions results in image bias and that bias is a serious challenge for today’s very high resolution applications. An approach to the design of an imaging system that provides gain “chemical amplification” without diffusion bias will be presented followed by a description of a new application of Professor Crivello’s onium salts in which the acid diffusion phenomenon offers a key advantage for imaging at 100 angstrom resolution and below.

High-resolution patterning through application of Crivello salts

251st National Meeting (2016)

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