Most surface imaging resist schemes are based on the selective diffusion of a Si‐containing compound into the resist. In the diffusion enhanced silylated resist process hexamethyldisilazane is being incorporated in the exposed regions during the silylation treatment. Upon deep ultraviolet irradiation (at 248 nm), novolac based resists will however crosslink to some extent. The crosslinking reaction influences the degree of silicon incorporation in the exposed resist and hence plays an important role in the imaging properties. The crosslinking reaction has been studied in detail in this work for two types of Plasmask deep‐ultraviolet resists, along with its consequences on resist imaging. A decrease in silicon incorporation due to crosslinking puts a serious limitation on the useful process window for Plasmask 150u, but the process window is not limited by crosslinking for Plasmask 301u. A thorough investigation of the influence of crosslinking on the pattern deformation is also carried out.