Polymer comprising repeat units with photoacid-generating functionality and base-solubility-enhancing functionality, and associated photoresist composition and electronic device forming method

1. A polymer comprising, based on 100 mole percent of total repeat units, 60 to 100 mole percent of photoacid-generating repeat units, wherein each of the photoacid-generating repeat units comprises (a) photoacid-generating functionality and (b) base-solubility-enhancing functionality selected from the group consisting of tertiary carboxylic acid esters, secondary carboxylic acid esters wherein the secondary carbon is substituted with at least one unsubstituted or substituted C 6-40 aryl, acetals, ketals, lactones, sultones, alpha-fluorinated esters, beta-fluorinated esters, alpha,beta-fluorinated esters, polyalkyleneglycols, alpha-fluorinated alcohols, and combinations thereof:

wherein the photoacid-generating repeat units have the structure

wherein

R 1 is independently in each of the repeat units H, F, —CN, C 1-10 alkyl, or C 1-10 fluoroalkyl;

L 1 is independently in each of the repeat units —O—, —C(O)—O—, unsubstituted C 6-18 arylene, or substituted C 6-18 arylene;

m is independently in each of the repeat units 0 or 1;

L 2 is independently in each of the repeat units an unsubstituted or substituted C 1-20 hydrocarbylene, wherein the substituted C 1-20 hydrocarbylene can, optionally, include one or more in-chain divalent heteroatom-containing groups that is —O—, —S—, —NR 2 , —PR 2 —, —C(O)—, —OC(O)O—, —N(R 2 )C(O)—, —C(O)N(R 2 )—, —OC(O)N(R 2 )—, —N(R 2 )C(O)O—, —S(O)—, —S(O) 2 —, —N(R 2 )S(O) 2 —, —S(O) 2 N(R 2 )—, —OS(O) 2 —, or —S(O) 2 O—, wherein R 2 is H or C 1-12 hydrocarbyl;

Z− is independently in each of the repeat units sulfonate (—SO 2 —), sulfonamidate, which is an anion of sulfonamide, —S(O) 2 N—R 3 , wherein R 3 is H or unsubstituted or substituted C1-12 hydrocarbyl, or sulfonimidate, which is an anion of sulfonamide, —S(O) 2 N − S(O) 2 R 3 , wherein R 3 is H or unsubstituted or substituted C1-12 hydrocarbyl; and

Q + is photoacid-generating cation;

wherein at least one of L 1 , L 2 (when m is 1), and Q + comprises the base-solubility-enhancing functionality.

2. The polymer of claim 1 , comprising 95 to 100 mole percent of the photoacid-generating repeat units.

3. The polymer of claim 1 , wherein the photoacid-generating repeat units are derived from a single monomer.

4. The polymer of claim 1 , wherein the photoacid-generating repeat units are derived from at least two different monomers.

5. The polymer of claim 1 , wherein the base-solubility-enhancing functionality is a tertiary carboxylic acid ester, an acetal, a ketal, a lactone, or a combination thereof.

6. A photoresist composition comprising the polymer of claim 1 and a solvent.

7. A method of forming an electronic device, comprising:

(a) applying a layer of the photoresist composition of claim 6 on a substrate;

(b) pattern-wise exposing the photoresist composition layer to activating radiation; and

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