Enhanced EUV photoresist materials, formulations and processes

A method of forming a patterned resist comprising:

• a. providing a substrate,
• b. applying a multiple trigger resist composition comprising:
• i. at least one polymer comprising two or more crosslinkable functionalities, wherein essentially all the functionalities are attached to acid labile protecting groups,
• ii. at least one acid activatable crosslinker,
• iii. at least one photoacid generator,
• iv. at least one solvent, and
• v. at least one xMT ester comprising a compound of one of the following structures:
• wherein at least one of X or Y comprises
• -(alkyl)j-(aryl)k-(O)p—(COO)q-LG
• wherein j, k, p, and q take the values in the following table:
• -alkyl-
• -aryl-
• —O—
• —COO—
• j
• k
• p
• q
• 1
• 1
• 1
• 1
• 1
• 1
• 0
• 1
• 1
• 1
• 1
• 0
• 1
• 0
• 0
• 1
• 1
• 0
• 1
• 0
• 0
• 1
• 1
• 1
• 0
• 1
• 0
• 1
• 0
• 1
• 1
• 0
• 0
• 0
• 0
• 1
• wherein alkyl is a branched or unbranched, substituted or unsubstituted divalent alkyl chain of 1-16 carbon atoms having 0-16 heteroatoms substituted into the chain, aryl is a substituted or unsubstituted divalent phenyl group, divalent heteroaromatic group, or divalent fused aromatic or fused heteroaromatic group, and wherein LG is a tertiary alkyl or tertiary cycloalkyl group, an alicyclic group, a ketal or cyclic aliphatic ketal, or an acetal is a leaving group,
• c. heating the coated substrate to form a substantially dried coating to obtain a desired thickness,
• d. imagewise exposing the coated substrate to actinic radiation,
• e. removing the unexposed areas of the coating using an aqueous developer, a solvent developer or a combination aqueous-solvent developer composition, wherein the remaining photoimaged pattern is optionally heated and wherein the exposed resist may be selectively heated prior to development and wherein the composition is free of any additional acid diffusion control components.