Characterization of 193 nm Chemically Amplified Resist during Post Exposure Bake and Post Exposure Delay

Abstract

We investigated the property change of a positive type 193 nm chemically amplified resist (CAR) during post exposure bake (PEB) and post exposure delay (PED). Upon PEB the thickness and optical property are changed. These changes depend on the exposure energy and the PEB conditions. The thickness and the imaginary refractive index changes during PEB are determined. The thickness reduction and the refractive index changes are related to the de-protection of the resist. By modeling these relationships the concentration of de-protected site of the resist and the parameters are determined. The PED effect is also considered and included in the model. The de-protection parameters needed for the 193 nm lithography are extracted. The obtained parameters are used with the lithography simulation for profile calculation, and the results are compared with the observed SEM resist profile.