Patent ID: 8110339

Claim:
A method for forming a pattern with a resist to perform lithography, comprising: applying a multi-tone resist on a substrate, the multi-tone resist comprising an acid generator and an aliphatic polymer, the aliphatic polymer having acid labile groups and a plurality of crosslinking sites bearing crosslinkable groups capable of crosslinking the aliphatic polymer, the crosslinkable groups comprising at least one of a crosslinkable hydroxide and a latent crosslinkable hydroxide; providing a first portion of the resist with exposure to a low dose of lithographic radiation, the low dose being less than a threshold amount wherein the acid labile groups maintain coupling to the aliphatic polymer, and the exposed first portion having limited solubility in a developer; selectively exposing a second portion of the resist to an intermediate dose of lithographic radiation, the intermediate dose being capable of activating removal of the acid labile groups, the exposed second portion being substantially soluble in the developer; selectively exposing a third portion of the resist to a higher dose of lithographic radiation, the higher dose being capable of inducing crosslinking of the aliphatic polymer at the plurality of crosslinking sites, the exposed third portion having limited solubility in the developer; contacting the resist with the developer to form the pattern.