An increasing number of nowadays advanced lithographic technologies require photoresist film thickness of at least 50μm. The patterning of high aspect ratio structures in ultra thick photoresist films is extremely challenging and the photoresists should provide low absorption in order to achieve vertical sidewalls and easy stripping after the pattern transfer processing. In the current work a novel resist platform is presented and applied in the case of film thicknesses up to 65μm. The resist formulation consists of a mixture of an epoxy novolac oligomer and poly(hydroxy styrene) and onium salt photoacid generators. Since the resist is rich in hydroxyl groups the unexposed regions can be developed in industrial aqueous solutions (TMAH 0.27N). Additionally since the required crosslink density is limited, the crosslinked regions can be easily removed by commercial wet photoresist strippers. First experimental data reveal a promising lithographic performance with resolution down to 30μm.