Methods to explore and prevent pattern collapse in thin film lithography

Abstract

Pattern collapse is becoming a critical issue as integrated circuit fabrication continues to advance towards the 32 nm node and below. Though line edge roughness and resolution are certainly important in moving forward, pattern collapse by both deformation and adhesion failure must be addressed. In this work, a post-development strategy to reduce pattern collapse by bending was developed whereby the hydroxyl functional groups on the surface of the resist were crosslinked via a dicarboxylic acid using carbodiimide chemistry. The pattern collapse of a hydroxystyrene-based, positive tone resist was then studied before and after the application of the reactive rinse. SEM analysis of the samples showed that application of the reactive rinse resulted in a clear increase in the printing capabilities of the resist, as the photoresist lines could be printed with smaller space widths corresponding to higher stresses after the rinse treatment.