Characteristics of 193 nm chemically amplified resist during post exposure bake and post exposure delay

Abstract

Lithography simulation can help selecting the process tools, techniques, and materials. It can also improve process control and precision. ArF excimer laser with 193 nm wavelength is believed to be the main lithography source for sub-100 nm device. So the characterization analysis of 193 nm chemically amplified resist (CAR) is necessary in order to extract the parameters' needed by the simulation model. For accurate simulation, good measurements and calculation of resist properties are needed, such as the optical constant and concentration of activated sites (C/sub as/). We investigated the characteristics of 193 nm CAR during post exposure bake (PEB) and post exposure delay (PED). We found that the optical constant is directly related to the C/sub as/ of the resist. We used the multiple thin film calculations with the measured thickness and transmittance to obtain the optical constant of the resist. The C/sub as/ change was obtained from optical constants. The thickness and the optical constant are changed with the exposure energy and PEB conditions, Especially the thickness change is directly related to the C/sub as/ change.