Investigation of trench and contact hole shrink mechanism in the negative tone develop process

The objective of this work was to study the trench and contact hole shrink mechanism in negative tone develop resist processes and its manufacturability challenges associated for 20nm technology nodes and beyond. Process delay from post-exposure to develop, or "queue time", is studied in detail. The impact of time link delay on resolved critical dimension (CD) is fully characterized for patterned resist and etched geometries as a function of various process changes. In this study, we assembled a detailed, theoretical model and performed experimental work to correlated time link delay to acid diffusion within the resist polymer matrix. Acid diffusion is determined using both a modulation transfer function for diffusion and simple approximation based on Fick's law of diffusion.