Accelerated purge drying to prevent pattern collapse without surfactant rinse for high-aspect ratio resist patterns

Abstract

We developed a pattern collapse prevention method which does not use a surfactant rinse agent. The pattern collapse phenomenon is commonly expressed by the stress applied on the pattern with key components including "the surface tension of the rinse agent" and "contact angle between pattern surface and rinse agent." Using a surfactant as a rinse agent is targeted at reducing "the surface tension of the rinse agent."The pattern collapse prevention method of focus in this report evaluates the "the drying rate of a rinse agent" and "the accumulated stress on a pattern" in relation to the pattern collapse phenomenon.By increasing the drying rate of the rinse agent, the integrated stress on the pattern is reduced allowing for the pattern collapse prevention. Dramatically speeding-up the drying rate of rinse agent by Accelerated Purge (AP) drying integrated into a photolithography track develop module and without using a surfactant rinse agent we have confirmed the ability to control the pattern collapse phenomenon. With AP drying we have also confirmed further defect reduction that would normally result from rinse agent remaining on a wafer, which has been significantly improved by the super-fast drying process. AP drying is a promising technology which can control pattern collapse phenomenon without using a surfactant rinse agent with advantages in yield improvement, process time reduction and chemical cost reduction.

Resist Materials and Processes for Extreme Ultraviolet Lithography

“…This is based on a previously developed wafer-drying technique that allows the prevention of contaminant adhesion and watermark-free wafer drying. 125) Preliminary results have shown its potential in reducing pattern collapse and in effect, improving process windows with the reduction in related defects.…”