Photoacid generators, photoresist compositions, and pattern formation methods

1. A photoacid generator, comprising a moiety of formula (1):

wherein: Ar 1 is a substituted or unsubstituted aryl group; R 1 is an alkyl or aryl group, each of which may be substituted or unsubstituted, wherein Ar 1 and R 1 are optionally connected together by a single bond or a divalent linking group to form a ring; Y is a single bond or a divalent group; and * is the point of attachment of the moiety to another atom of the photoacid generator, wherein the photoacid generator is non-ionic.

2. The photoacid generator of claim 1 , wherein the non-ionic photoacid generator is chosen from nitrobenzyl derivatives, diazomethane derivatives, sulfonic acid ester derivatives, glyoxime derivatives, β-ketosulfone derivatives, disulfone derivatives, nitrobenzyl sulfonate derivatives, imido-yl sulfonate-derivatives, oxime sulfonate derivatives, imino sulfonate derivatives, and triazine derivatives.

3. The photoacid generator of claim 1 , wherein the photoacid generator is in polymeric form.

4. A photoresist composition, comprising a photoacid generator of claim 1 and a solvent.

5. The photoresist composition of claim 4 , wherein the photoresist composition comprises an acid-sensitive polymer.

6. A pattern formation method, comprising:

(a) forming a photoresist layer from a photoresist composition of claim 4 on a substrate;

(b) exposing the photoresist layer to activating radiation; and

(c) developing the exposed photoresist layer to provide a resist relief image.