The line edge roughness improvement with plasma coating for 193nm lithography

Incorporation of self-aligned multiple patterning (SaMP) techniques have had limited uses in the industry due to a number of issues including: pitching walking, initial line width roughness (LWR) of photoresist, line edge roughness (LER) degradation of subsequent layer patterning. Utilizing plasma coating for PR hardening is attractive for 193nm lithography application. This paper presents the design of experiments (DOE) to optimize the parameters of pressure, RF power and chemistry ratio to achieve the optimal condition on the LER improvement. As a result, the LER of 1st layer is improved 32% at dense pattern region comparing to initial condition.