The mechanisms of the formation of microgroove and protuberance defects in novolac/diazonaphthoquinone resists were studied and found to be influenced by the resist composition, the degree of substrate silylation, and the developer composition. Low molecular chains in the novolac polymer and high PAC contents promote the formation of microgrooves and protuberances. A mechanism is proposed wherein short polymer chains migrate toward the substrate interface and PAC migrates away from the substrate during post-bake; this migration enhances the dissolution rate near the substrate, leading to an undercut. The possibility that the migration of developer along the resist/substrate interface occurs through percolative diffusion is explored. Developer-induced hydrolysis of trimethylsilyl groups from the silylated substrate is shown to be a contributory mechanism in the formation of microgrooves. Adding select surfactants to the developer is shown to reduce the rate of substrate desilylation and inhibit microgroove formation.