The Dry Development Process of Tmsdea-Treated Photoresist by Using Oxygen-Helium Plasma in Reactive Ion Etching Mode

Abstract

Silylation and dry development are the key processes of DESIRE, one of the surface imaging techniques in submicron lithography. The present work was carried out to achieve the improvement of develoment rate and anisotropic resist profile, and to characterize the silylated and dry developed resist. The dependence of silylation on the exposure dose and the presilylation baking temperature was investigated by using Rutherford backscattering spectrometry. The higher dose UV-irradiation results the thicker silylated layer in the dyed resist. The dry development of photoresisl patterns was processed newly by using the plasma of O2/He RIE plasma. It is particularly emphasized to obtain to optimize the RIE process, so that some improvements, i.e., vertical resist profiles with the high anisotropy, good selectivity, and the development rate of 0.4 µm/min were achieved. X-ray photoelectron spectroscopic study indicated that Si in the silylated and dry developed resist was present with the chemical binding states of SiO2 on surface, and SiO. SiC and very small amount of SiO2 in near-Surface region (at about 5 nm depth).