Az 12XT is a chemical enhanced positive tone photo resist (PR). In a chemical enhanced PR the exposure step creates a latent image and a week acid in the PR. The chemical reaction that makes the PR soluble in developer happens during the post exposure bake (PEB). This makes the length and temperature of the PEB extremely important. One of the advantages of the chemical enhance resits for thick resist is that it eliminate the waiting steps.
===for 10-17um layers===