Understanding the role of base quenchers in photoresists

Abstract

As critical dimensions in microlithography become ever smaller and the importance of line edge roughness becomes more pronounced, it is becoming increasingly important to gain a fundamental understanding of how the chemical composition of modern photoresists influences resist performance. Modern resists contain four basic components: polymer, photoacid generator, dissolution inhibitor, and base quencher. Of these four components, the one that is least understood is the base quencher. This paper examines the influence of base additives on line edge roughness, contrast, photospeed, and isofocal critical dimension (CD). A mathematical model describing the tradeoff between contrast and photospeed is developed, line edge roughness values for different base types and loadings are reported, and isofocal CD is shown for various photoacid types as well as for different base types and loadings.