Near UV photoresist
AssigneeShipley Company, L.L.C.
InventorsAngelo A. Lamola, Gary Calabrese, Roger Sinta
Life of this patent
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Abstract
A photoacid-generating photoresist composition sensitized with an aromatic, multi-ring, heterocylcic nitrogen containing sensitizer, preferably a ring extended phenothiazine derivative. The use of the sensitizer permits exposure of photoresists to near UV irradiation where such photoresists have heretofore been exposed to deep UV irradiation. The invention is especially useful for acid hardening photoresist systems.
Claims22
A photoresist composition comprising an acid hardening resin system consisting of a phenolic resin and an aminoplast resin, a halogenated organic, photoacid generating compound that is other than an onium salt and capable of generating a halogen acid upon exposure to actinic radiation, and a sensitizer capable of sensitizing the photoresist to exposure within the range of 360 to 450 nm, said sensitizer having the structural formula:
- ##STR3## where R is selected from the group of hydrogen, alkyl having one to eight carbon atoms and aryl;
- X is selected form the group consisting of sulfur, oxygen, selenium and tellurium;
- R.sub.1 and R.sub.2 are selected from the group consisting of hydrogen, halogen, lower alkyl, alkoxy, aryl, a phenothiazine radical or R.sub.1 and R.sub.2 taken together form an aromatic ring fused to the sensitizer nucleus in the first and second positions on the nucleus, the second and third positions on the nucleus, or the third and fourth positions on the nucleus, R.sub.3 and R.sub.4 are selected from the same group as R.sub.1 and R.sub.2, or R.sub.3 and R.sub.4 taken together form an aromatic ring fused to the sensitizer nucleus in the sixth and seventh positions of the nucleus, the seventh and eighth positions of the nucleus, or the eighth and ninth positions of he nucleus;
- provided that at least one of R.sub.1, R.sub.2, R.sub.3 or R.sub.4 is aryl or R.sub.1 and R.sub.2 taken together, or R.sub. 3 and R.sub.4 taken together, are part of an aryl group;
- said sensitizer being present in a concentration sufficient to absorb sufficient energy whereby, upon exposure to irradiation within a range of from 360 to 450 nm, photoactivation of the photoacid generating compound occurs.
A method for sensitizing a photoresist to irradiation within a range of from 360 to 450 nm said photoresist comprising an acid hardening resin system consisting of a phenolic resin and an aminoplast resin, and a halogenated organic, photoacid generating compound that is other than an onium salt and capable of generating a halogen acid upon exposure to actinic radiation, said method comprising addition of a phenothiazine to said photoresist in an amount sufficient to absorb energy whereby, upon exposure to irradiation within a range of from 360 to 450 nm, photoactivation of the photoacid generator occurs, said phenothiazine conforming to the formula:
- ##STR4## where R is selected from the group consisting of hydrogen, alkyl having one to eight carbon atoms and aryl;
- X is selected from the group consisting of sulfur, oxygen, selenium and tellurium;
- R.sub.1 and R.sub.2 are selected from the group consisting of hydrogen, halogen, lower alkyl, alkoxy, aryl, a phenothiazine radical or R.sub.1 and R.sub.2 taken together form an aromatic ring fused to the sensitizer nucleus in the first and second positions on the nucleus, the second and third positions on the nucleus, or the third and fourth positions on the nucleus, R.sub.3 and R.sub.4 are selected from the same group and R.sub.1 and R.sub.2 or R.sub.3 and R.sub.4 taken together form an aromatic ring fused to the sensitizer nucleus in the sixth and seventh positions of the nucleus, the seventh and eighth positions of the nucleus, or the eighth and ninth positions of the nucleus;
- provided that at least one of R.sub.1, R.sub.2, R.sub.3 or R.sub.4 is aryl or R.sub.1 and R.sub.2 taken together, or R.sub.3 and R.sub.4 taken together are part of an aryl group.
A photoresist composition comprising an acid hardening resin system consisting of a phenolic resin and an aminoplast resin, a photoacid generating compound other than an onium salt and a sensitizer capable of sensitizing the photoresist to exposure within the range of 360 to 450 nm, said sensitizer having the structural formula:
- ##STR5## where R is selected form the group of hydrogen, alkyl having one to eight carbon atoms and aryl;
- X is selected form the group consisting of sulfur, oxygen, selenium and tillurium;
- R.sub.1 and R.sub.2 are selected form the group consisting of hydrogen, halogen, lower alkyl, alkoxy, aryl, a phenothiazine radical or R.sub.1 and R.sub.2 taken together form an aromatic ring fused to the sensitizer nucleus in the first and second positions on the nucleus, the second and third positions on the nucleus, or the third and fourth positions on the nucleus, R.sub.3 and R.sub.4 are selected from the same group as R.sub.1 and R.sub.2, or R.sub.3 and R.sub.4 taken together form an aromatic ring fused to the sensitizer nucleus in the sixth and seventh positions of the nucleus, the seventh and eighth positions of the nucleus, or the eighth and ninth positions of the nucleus;
- provided that at least one of R.sub.1, R.sub.2, R.sub.3 or R.sub.4 is aryl or R.sub.1 and R.sub.2 taken together, or R.sub. 3 and R.sub.4 taken together, are part of an aryl group;
- said sensitizer being present in a concentration sufficient to absorb sufficient energy whereby, upon exposure to irradiation within a range of form 360 to 450 nm, photoactivation of the photoacid generating compound occurs.
Dependencies are inferred from the claim text.