Alkaline-resistant negative photoresist for silicon wet-etch without silicon nitride
New photoresists for use during the production of semiconductor and MEMS devices are provided. The primer layer preferably comprises a silane dissolved or dispersed in a solvent system. The photoresist layer includes a first polymer prepared from a styrene and an acrylonitrile, and a second polymer comprising epoxy-containing monomers (and preferably phenolic-containing monomers). The photoresist layer comprises a photoacid generator, and is preferably negative-acting.
1. A photosensitive composition useful as a protective layer, said composition being alkaline-resistant and negative-acting and said composition comprising a first polymer, a second polymer, and a photoacid generator dissolved or dispersed in a solvent system, wherein:
said first polymer comprises:
wherein:
each R 1 is individually selected from the group consisting of hydrogen and C 1 -C 8 alkyls; and
each R 2 is individually selected from the group consisting of hydrogen, and C 1 -C 8 alkyls, wherein said first polymer comprises from about 50% to about 90% by weight of (I) and from about 10% to about 50% by weight of (II); and
said second polymer comprises recurring monomers comprising epoxy groups.
2. The composition of claim 1 , wherein said second polymer further comprises recurring monomers comprising phenolic groups.
3. The composition of claim 1 , wherein said second polymer is selected from the group consisting of epoxy phenol novolac resins, epoxy bisphenol A/F resins, epoxy cresol novolac resins, epoxy bisphenol A resins, and epoxy bisphenol A novolac resins.
4. The composition of claim 1 , wherein said photoacid generator is selected from the group consisting of triarylsulfonium hexafluoroantimonate, triarylsulfonium hexafluoro-phosphates, diaryliodonium hexafluoroantimonate, diaryliodonium hexafluorophosphate,
wherein each R 3 is individually selected from the group consisting of C 3 H 7 , C 8 H 17 , CH 3 C 6 H 4 , and camphor.
5. A method of forming a microelectronic structure, said method comprising:
providing a microelectronic substrate;
applying a primer layer to said substrate, said primer layer comprising a silane dispersed or dissolved in a solvent system;
applying a photosensitive layer to said primer layer, said photosensitive layer being alkaline-resistant and comprising a photoacid generator, a first polymer, and a second polymer dispersed or dissolved in a solvent system, wherein:
said first polymer comprises:
wherein:
each R 1 is individually selected from the group consisting of hydrogen and C 1 -C 8 alkyls; and
each R 2 is individually selected from the group consisting of hydrogen, and C 1 -C 8 alkyls, wherein said first polymer comprises from about 50% to about 90% by weight of (I) and from about 10% to about 50% by weight of (II); and
said second polymer comprises recurring monomers comprising epoxy groups.
6. The method of claim 5 , wherein said second polymer further comprises recurring monomers comprising phenolic groups.
7. The method of claim 5 , wherein said second polymer is selected from the group consisting of epoxy phenol novolac resins, epoxy bisphenol A/F resins, epoxy cresol novolac resins, epoxy bisphenol A resins, and epoxy bisphenol A novolac resins.
8. The method of claim 5 , wherein said photoacid generator is selected from the group consisting of triarylsulfonium hexafluoroantimonate, triarylsulfonium hexafluoro-phosphates, diaryliodonium hexafluoroantimonate, diaryliodonium hexafluorophosphate,
wherein each R 3 is individually selected from the group consisting of C 3 H 7 , C 8 H 17 , CH 3 C 6 H 4 , and camphor.
9. The method of claim 5 , wherein said polymer comprises from about 50% to about 90% by weight of (I) and from about 10% to about 50% by weight of (II), based upon the total weight of the polymer taken as 100% by weight.
10. The method of claim 5 , said silane having a formula selected from the group consisting of
each of i, j, and k is individually selected from the group consisting of 0 and 1, and if one of i and j is 1, then the other of i and j is 0;
each R 4 is individually selected from the group consisting of hydrogen, the halogens, C 1 -C 8 alkyls, C 1 -C 8 alkoxys, C 1 -C 8 haloalkyls, aminos, and C 1 -C 8 alkylaminos;
each R 5 is individually selected from the group consisting of C 1 -C 8 aliphatic groups;
each R 6 is individually selected from the group consisting of hydrogen and haloalkyls;
each X is individually selected from the group consisting of halogens, hydroxyls, C 1 -C 4 alkoxys and C 1 -C 4 carboxyls;
Y is selected from the group consisting of oxygen and sulfur;
Z is selected from the group consisting of nitrogen and phosphorus; and
each d is individually selected from the group consisting of 0 and 1; and
wherein:
each R 7 is individually selected from the group consisting of hydrogen, the halogens, C 1 -C 8 alkyls, C 1 -C 8 alkoxys, C 1 -C 8 haloalkyls, aminos, and C 1 -C 8 alkylaminos; and
each R 8 is individually selected from the group consisting of C 1 -C 8 aliphatic groups.
11. The method of claim 5 , said silane being selected from the group consisting of aminoalkoxysilanes, phenylsilanes, and diphenylsilanes.
12. The method of claim 11 , wherein said silane is selected from the group consisting of aminoalkylalkoxysilanes and phenylaminoalkylalkoxysilanes.
13. The method of claim 11 , wherein said silane is selected from the group consisting of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, N-phenylaminopropyltrimethoxysilane, N-phenylaminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-mercaptopropyl-trimethoxysilane, phenyltrimethoxysilane, phenyltrichlorosilane, phenyltriethoxysilane, phenyltriacetoxysilane, diphenyldimethoxysilane, diphenyldichlorosilane, diphenylsilanediol 2-phenylethyltrialkoxysilane, p/m-chlorophenyltrimethoxysilane, p/m-bromophenyltrimethoxysilane, (p/m-chloromethyl)phenyltrimethoxysilane, 2-(p/m-methoxy)phenylethyltrimethoxysilane, 2-(p/m-chloromethyl)phenylethyltrimethoxysilane, 3,4-dichlorophenyltrichlorosilane, 3-phenoxypropyltrichlorosilane, 3-(N-phenylamino)propyltrimethoxysilane, and 2-(diphenylphosphino)ethyltriethoxysilane.
14. The method of claim 5 , further comprising baking said primer layer after said primer layer applying.
15. The method of claim 14 , wherein said primer layer further comprises a catalyst, and said primer layer baking results in crosslinking of said silane.
16. The method of claim 5 , further comprising baking said photosensitive layer after said photosensitive layer applying.
17. The method of claim 16 , wherein said baking causes at least one of said polymers of said photosensitive layer to covalently bond with the silane of said primer layer.
18. The method of claim 5 , further comprising exposing a first portion of said photosensitive layer to actinic radiation while a second portion of said photosensitive layer is not exposed to actinic radiation.
19. The method of claim 18 , further comprising baking said photosensitive layer after said exposing to actinic radiation.
20. The method of claim 19 , wherein said first portion of said photosensitive layer crosslinks during said baking.
21. The method of claim 19 , further comprising developing said photosensitive layer.
22. The method of claim 21 , wherein said developing results in the second portion of said photosensitive layer being substantially removed during said developing step so as to form a stack including a photosensitive layer having a pattern formed therein.
23. The method of claim 22 , further comprising baking said photosensitive layer after said developing.
24. The method of claim 22 , further comprising etching said stack so as to transfer the pattern of said photosensitive layer to said substrate.
25. The method of claim 24 , wherein said photosensitive layer exhibits less than about 20% undercutting after said etching.
26. The method of claim 24 , wherein said photosensitive layer exhibits less than about 0.1 pinholes per cm 2 of substrate.
27. The method of claim 5 , wherein said substrate is selected from the group consisting of Si substrates, SiO 2 substrates, Si 3 N 4 substrates, SiO 2 on silicon substrates, Si 3 N 4 on silicon substrates, glass substrates, quartz substrates, ceramic substrates, semiconductor substrates, and metal substrates.
28. A microelectronic structure comprising:
a microelectronic substrate;
a primer layer adjacent said substrate, said primer layer comprising a crosslinked silane;
a photosensitive layer adjacent said primer layer, said photosensitive layer being alkaline-resistant and comprising:
a first polymer comprising:
wherein:
each R 1 is individually selected from the group consisting of hydrogen and C 1 -C 8 alkyls; and
each R 2 is individually selected from the group consisting of hydrogen, and C 1 -C 8 alkyls, wherein said first polymer comprises from about 50% to about 90% by weight of (I) and from about 10% to about 50% by weight of (II); and
a second polymer comprising recurring monomers comprising crosslinked epoxy groups.
29. The microelectronic structure of claim 28 , wherein said second polymer further comprises recurring monomers comprising phenolic groups.
30. The microelectronic structure of claim 28 , wherein said second polymer is selected from the group consisting of epoxy phenol novolac resins, epoxy bisphenol A/F resins, epoxy cresol novolac resins, epoxy bisphenol A resins, and epoxy bisphenol A novolac resins.
31. The microelectronic structure of claim 28 , wherein said silane comprises an amine, and the second polymer of said photosensitive layer comprises an epoxy group covalently bonded with said amine.
32. The microelectronic structure of claim 28 , wherein said polymer comprises from about 50% to about 90% by weight of (I) and from about 10% to about 50% by weight of (II), based upon the total weight of the polymer taken as 100% by weight.
33. The microelectronic structure of claim 28 , said silane having a formula selected from the group consisting of
each of i, j, and k is individually selected from the group consisting of 0 and 1, and if one of i and j is 1, then the other of i and j is 0;
each R 4 is individually selected from the group consisting of hydrogen, the halogens, C 1 -C 8 alkyls, C 1 -C 8 alkoxys, C 1 -C 8 haloalkyls, aminos, and C 1 -C 8 alkylaminos;
each R 5 is individually selected from the group consisting of C 1 -C 8 aliphatic groups;
each R 6 is individually selected from the group consisting of hydrogen and haloalkyls;
each X is individually selected from the group consisting of halogens, hydroxyls, C 1 -C 4 alkoxys and C 1 -C 4 carboxyls;
Y is selected from the group consisting of oxygen and sulfur;
Z is selected from the group consisting of nitrogen and phosphorus; and
each d is individually selected from the group consisting of 0 and 1; and
wherein:
each R 7 is individually selected from the group consisting of hydrogen, the halogens, C 1 -C 8 alkyls, C 1 -C 8 alkoxys, C 1 -C 8 , haloalkyls, aminos, and C 1 -C 8 alkylaminos; and
each R 8 is individually selected from the group consisting of C 1 -C 8 aliphatic groups.
34. The microelectronic structure of claim 28 , said silane being selected from the group consisting of aminoalkoxysilanes, phenylsilanes, and diphenylsilanes.
35. The microelectronic structure of claim 34 , wherein said silane is selected from the group consisting of aminoalkylalkoxysilane and phenylaminoalkylalkoxysilanes.
36. The microelectronic structure of claim 34 , wherein said silane is selected from the group consisting of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, N-phenylaminopropyltrimethoxysilane, N-phenylaminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-mercaptopropyl-trimethoxysilane, phenyltrimethoxysilane, phenyltrichlorosilane, phenyltriethoxysilane, phenyltriacetoxysilane, diphenyldimethoxysilane, diphenyldichlorosilane, diphenylsilanediol 2-phenylethyltrialkoxysilane, p/m-chlorophenyltrimethoxysilane, p/m-bromophenyltrimethoxysilane,(p/m-chloromethyl)phenyltrimethoxysilane, 2-(p/m-methoxy)phenylethyltrimethoxysilane, 2-(p/m-chloromethyl)phenylethyltrimethoxysilane, 3,4-dichlorophenyltrichlorosilane, 3-phenoxypropyltrichlorosilane, 3-(N-phenylamino)propyltrimethoxysilane, and 2-(diphenylphosphino)ethyltriethoxysilane.
37. The microelectronic structure of claim 28 , wherein said substrate is selected from the group consisting of Si substrates, SiO 2 substrates, Si 3 N 4 substrates, SiO 2 on silicon substrates, Si 3 N 4 on silicon substrates, glass substrates, quartz substrates, ceramic substrates, semiconductor substrates, and metal substrates.
38. The microelectronic structure of claim 28 , wherein said crosslinked epoxy groups have the formula
39. The composition of claim 1 , wherein said first polymer first polymer comprises from about 60% to about 80% by weight of (I) and from about 20% to about 40% by weight of (II).
40. The composition of claim 1 , wherein said first polymer is a copolymer of (I) and (II).