A new process, dry developable chemically amplified resist system, was proposed. A new matrix polymer for this process was synthesized and characterized. The thermal deprotection of 2-trimethylsilyl-2-propyl group of the matrix polymer takes place at 200 degree(s)C, whereas the acid catalyzed deprotection begins at 100 degree(s)C. The difference of silicon content between unexposed region and exposed regions is large enough to form patterns using oxygen reactive-ion etching. The etching selectivity of the unexposed region to the exposed region was about 142. The matrix polymer has good transmittance at 248 nm and 193 nm. In addition, the polymer possesses good thermal stability up to 200 degree(s)C and high Tg.