Antireflective coating compositions

1. An antireflective coating composition comprising a polymer which does not contain an aromatic chromophore, and a thermal acid generator, where the polymer comprises a structural unit derived from a diacid, a triacid, a dianhydride or its corresponding tetraacid or a mixture thereof and a structural unit derived from a diol, a triol, a diepoxy containing compound, a triepoxy containing compound, or mixture thereof, wherein the polymer comprises a moiety 3 and further where the polymer comprises a repetitive unit of structure (1) or (2)

where each of Y and Y1 independently are a non-aromatic linking moiety; each of Z and Z1 independently are the structural unit derived from a group selected from a diol, a triol, a diepoxy containing compound, a triepoxy containing compound, a diepoxy compound containing a moiety 3 and a triepoxy compound containing a moiety 3; each of R 1 and R 10 independently are hydrogen or the structural unit derived from a monoepoxy containing compound; each of R 2 and R 20 are independently selected from structural unit derived from a diepoxy containing compound, structural unit derived from a triepoxy containing compound, structural unit derived from a diepoxy compound containing a moiety 3, and structural unit derived from a triepoxy containing compound-containing a moiety 3, provided an epoxy group is present such that the polymer is capable of forming a self crosslinked polyester; each of Q1, Q2, Q3, and Q4 are independently a direct bond or an unsubstituted or substituted C 1-4 alkylene; each of h and h1 are 1; and each of k or k1 independently are 0 or 1,wherein moiety 3 is

2. The antireflective coating composition of claim 1 wherein the composition further comprises an aromatic chromophore.

3. The antireflective coating composition of claim 1 , further comprising a crosslinker.

4. The antireflective coating composition of claim 1 wherein h is 1 and k is 1.

5. The antireflective coating composition of claim 1 where Y is selected from unsubstituted or substituted C 1 -C 20 alkylene, unsubstituted or substituted C 1 -C 20 cycloaliphatic, and unsubstituted or substituted C 1 -C 20 heterocycloaliphatic moiety.

6. The antireflective coating composition of claim 1 where Y is selected from

7. The antireflective coating composition of claim 1 wherein the polymer has a repetitive unit selected from

8. The antireflective coating composition of claim 1 where R 1 is the residue of a monoepoxy containing compound.

9. The antireflective coating composition of claim 1 which further comprises a solvent.

10. The antireflective coating composition of claim 9 where the solvent is selected from propylene glycol methyl ether, propylene glycol methyl ether acetate, cyclohexanone, 2-heptanone, ethyl 3-ethoxy-propionate, propylene glycol methyl ether acetate, ethyl lactate, gamma valerolactone, methyl 3-methoxypropionate, and mixtures thereof.

11. A coated substrate comprising a substrate having thereon an antireflective coating layer formed from the antireflective coating composition of claim 1 , where the antireflective coating layer has an absorption parameter (k) in the range of 0.01≦k<0.35 when measured at 193 nm.

12. A process for forming an image comprising, a) coating and baking a substrate with the antireflective coating composition of claim 1 ; b) coating and baking a photoresist film on top of the antireflective coating; c) imagewise exposing to radiation the photoresist; d) developing an image in the photoresist; e) optionally, baking the substrate after the exposing step.

13. A process for patterning a substrate by lithography wherein, a bottom layer is formed on a substrate with the antireflective coating composition according to claim 1 ; an intermediate resist layer is formed on the bottom resist layer by using an intermediate resist layer composition containing silicon atoms; a top resist layer is formed on the intermediate resist layer by using a top resist layer composition of a photoresist composition, to form a trilayer resist film; a pattern circuit area of the top resist layer is exposed to radiation and then developed with a developer to form a resist pattern on the top resist layer; the intermediate resist layer is etched using as a mask the top resist layer on which the pattern is formed; the bottom resist layer is etched using as a mask at least the intermediate resist layer on which the pattern is formed; and then the substrate is etched using as a mask at least the bottom resist layer on which the pattern is formed, to form the pattern on the substrate.

14. The composition of claim 1 , where the polymer comprises a moiety comprising a moiety 3 with an epoxy group.