DRY DEVELOPMENT OF SURFACE IMAGING RESISTS - A MAJOR PARAMETER FOR PROCESS OPTIMIZATION

Most surface imaging resist processes are based on selective incorporation of silicon during silylation, followed by dry development of the resist. The dry development is an important parameter in the resist processing, because it will influence the resist profile and the sensitivity to residues, and, hence, the process latitude. For the DESIRE process, the silicon diffusion profile will be more steep by applying a so called two step dry development, which will result in a steeper resist profile and less residue. For several dry development schemes, the resist profile and the sensitivity to residue are investigated. The etch selectivities corresponding to the various development processes are measured, since they play a major role in the resulting lithographic performance. Further, the useful silylation window with respect to silicon incorporation and DUV induced crosslinking is determined for each type of development. Finally, the resolution and the process latitudes resulting from the different development processes are compared.