Depth Profile Analysis of Structures in ArF Resists by 172nm VUV Curing and Dry Etching Process Using .MU.-FTIR with Gradient Shaving Preparation

Abstract

The structural changes in the depth direction of ArF model resist with the VUV curing and/or the dry etching process were investigated by the combined use of a gradient shaving preparation and micro-FTIR line scanned measurements. The effect on the improvement in the resistance against the dry etching process by the VUV curing was also clarified. It was cleared that the estimated thickness of the layer, which was damaged by the dry etching, was approximately 50nm with out the VUV curing. Additionally, it was found that both of the dry etching process and the VUV curing decreased lactone group and formed carboxylic acid, but the degree of the structural change by the VUV curing was clearly greater than that by the dry etching process. It was confirmed that the VUV curing process had the effect on reducing the film shrinkage and the surface roughness by the dry etching process. In addition, the damaged layer by the dry etching process was not formed in the VUV cured samples. It was supposed that the improvement in the resistance against the dry etching process by the VUV curing was caused by the structural changes, which were the creation of carboxylic acid with the decrease of lactone group and the formation of the network structure.