Alkaline-resistant negative photoresist for silicon wet-etch without silicon nitride

• US 7,709,178 B2
• Filed: 04/17/2007
• Issued: 05/04/2010
• Est. Priority Date: 04/17/2007
• Status: Active Grant

• Current Assignee: Brewer Science Inc.
• Original Assignee: Brewer Science Inc.
• Inventors: Malhotra, Jyoti, Flaim, Tony D., Zhong, Xing-Fu
• Primary Examiner(s): Walke; Amanda C.
• Application Number:
  US11/736,429
• Publication Number:
  US 20080261145A1
• Time in Patent Office: 1,113 Days
• Field of Search: 430/270.1, 430/907, 430/914
• US Class Current: 430/270.1
• CPC Class Codes: G03F 7/0045 with organic non-macromolecular light-sensitive compounds not otherwise provided for, e.g. dissolution inhibitors
• CPC Class Codes: G03F 7/0382 the macromolecular compound being present in a chemically amplified negative photoresist composition
• CPC Class Codes: G03F 7/0751 used as adhesion-promoting additives or as means to improve adhesion
• CPC Class Codes: G03F 7/0752 in non photosensitive layers or as additives, e.g. for dry lithography
• CPC Class Codes: Y10S 430/108 Polyolefin or halogen containing
• CPC Class Codes: Y10S 430/115 Cationic or anionic

Abstract

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.

Claims

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;

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,

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).

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;

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,

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

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 cm² of substrate.

27. The method of claim 5, wherein said substrate is selected from the group consisting of Si substrates, SiO₂ substrates, Si₃N₄ substrates, SiO₂ on silicon substrates, Si₃N₄ 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;

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

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, SiO₂ substrates, Si₃N₄ substrates, SiO₂ on silicon substrates, Si₃N₄ 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