The degradation of PMMA, irradiated with a Philips deep-UV source, was studied by means of gel permeation chromatography (GPC). A steep increase of the dissolution rate in MIBK was found with only a small decrease in molweight. This result supports Ouano's hypothesis of pore formation in PMMA upon E-beam irradiation, due to chemical degradation of the polymer. The sensitivity and contrast value of PMMA and PMIPK was determined, using 1 min. dip development in2MIBK. The minimum deerUV dose (200-300 nm.) needed to clear the film ranged from 750 mJ/cm2 for PMMA to 65 mJ/cm2 for sensitized PMIPK, with contrast values between 2.5 and 3.7. The plasma etch resistance of PMMA increased five-fold when the resist was mixed with an aromatic polymer, without loss of resolution or contrast. The sensitivity, contrast, resolution and plasma etch resistance of PMIPK based resist could be made as good as or better than that of existing positive photoresists.