Photoresist suitable for use in 157 nm photolithography and including a polymer based on fluorinated norbornene derivatives

1. A polymer comprising repeating units of the following general formula:

wherein:

each ofR1–R5, independently of each other, is H, F or a fluorine-substituted alkyl group having preferably 1–6 carbon atoms;

R6 is an acid-labile group, including tert-alkyl ester, tert-butoxycarbonyloxy, tert-butoxycarbonylmethyl, tetrahydrofuranyl, tetrahydropyranyl, tert-butyl ether, lactone or acetal groups, and at least one of the hydrogen atoms contained in the acid-labile groups is substituted with fluorine atoms;

Y is a straight-chain or branched alkyl group including 1 to 6 carbon atoms, the straight-chain or branched alkyl group being at least partially fluorinated and including functional groups having acetal, ketal, carboxyl groups, ether groups, a hetero atom and/or a carbonyl group;

m is 0 or 1;

k is 0 or an integer from 1 to 3; and

at least two of R1–R3 include at least one of a fluorine atom and a fluoroalkyl group.

2. The polymer of claim 1 , wherein R4 and R5 are trifluoromethyl groups.

3. The polymer of claim 1 , wherein R1 and R2 are fluorine atoms.

4. The polymer of claim 1 , wherein:

m =1; and

k=0.

5. The polymer of claim 1 , wherein:

R1–R3 are fluorine atoms;

R4 and R5 are trifluoromethyl groups;

Y is a CH 2 —CH 2 group;

R6 is H or an acid-labile group;

m =1; and

k=0.

6. The polymer of claim 1 , wherein the average molecular weight of the polymer is from 1000 to 200,000.

7. The polymer of claim 1 , wherein the polymer includes other monomers in a proportion of less than 30% by weight of the polymer.

8. The polymer of claim 1 , wherein the polymer includes other monomers in a proportion of less than 10% by weight of the polymer.

9. The polymer of claim 1 , wherein the polymer includes different repeating units of the general formula I.

10. A photoresist comprising a polymer as recited in claim 1 , a photo acid generator, and a solvent.

11. A process for structuring substrates, comprising:

coating a substrate with a photoresist as recited in claim 10 to obtain a photoresist film;

exposing the photoresist film in selected sections to light having a wavelength of less than 200 nm;

developing the exposed photoresist film to form a structure; and

transferring the structure to the substrate.

12. The process of claim 11 , wherein the photoresist film is exposed to light having a wavelength of 157 nm.