Spin-on protective coatings for wet-etch processing of microelectronic substrates

• US 7,758,913 B2
• Filed: 06/30/2006
• Issued: 07/20/2010
• Est. Priority Date: 01/16/2004
• Status: Active Grant

• Current Assignee: Brewer Science Inc.
• Original Assignee: Brewer Science Inc.
• Inventors: Ruben, Kimberly A., Flaim, Tony D., Li, Chenghong
• Primary Examiner(s): Talbot; Brian K
• Application Number:
  US11/428,123
• Publication Number:
  US 20060240181A1
• Time in Patent Office: 1,481 Days
• Field of Search: 427/58, 427/96.2, 427/97.1, 427/384
• US Class Current: 427/96.2
• CPC Class Codes: B81C 1/00539 Wet etching
• CPC Class Codes: C03C 15/00 Surface treatment of glass, not in the form of fibres or filaments, by etching etching or surface-brightening compositions, in general C09K13/00
• CPC Class Codes: C03C 2218/355 Temporary coating
• CPC Class Codes: C09D 125/12 with unsaturated nitriles
• CPC Class Codes: H01L 21/3081 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/31144 using masks
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/3154 Of fluorinated addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31544 Addition polymer is perhalogenated
• CPC Class Codes: Y10T 428/31612 As silicone, silane or siloxane
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane
• CPC Class Codes: Y10T 428/31678 Of metal
• CPC Class Codes: Y10T 428/31935 Ester, halide or nitrile of addition polymer

Abstract

New protective coating layers for use in wet etch processes during the production of semiconductor and MEMS devices are provided. The layers include a primer layer, a first protective layer, and an optional second protective layer. The primer layer preferably comprises an organo silane compound in a solvent system. The first protective layer includes thermoplastic copolymers prepared from styrene, acrylonitrile, and optionally other addition-polymerizable monomers such as (meth)acrylate monomers, vinylbenzyl chloride, and diesters of maleic acid or fumaric acid. The second protective layer comprises a highly halogenated polymer such as a chlorinated polymer which may or may not be crosslinked upon heating.

Claims

1. A method of forming a microelectronic structure, said method comprising the step of applying a first protective layer to a microelectronic substrate surface, said first protective layer including a polymer comprising recurring monomers having the respective formulas

2. The method of claim 1, wherein said polymer comprises at least about 50% by weight of monomer I, based upon the total weight of the polymer taken as 100% by weight.

3. The method of claim 1, wherein said polymer comprises at least about 15% by weight of monomer (II), based upon the total weight of the polymer taken as 100% by weight.

4. The method of claim 1, further comprising the step of applying a primer layer to said substrate surface prior to said first protective layer applying step.

5. The method of claim 4, said primer layer comprising an aromatic silane.

6. The method of claim 5, said aromatic silane having the structure

7. The method of claim 5, wherein said substrate surface comprises a plurality of surface hydroxyl groups, said method further comprising the step of heating said primer layer so that said aromatic silane from said primer layer bonds with at least some of said surface hydroxyl groups.

8. The method of claim 4, further comprising the step of heating said first protective layer so that it bonds with said primer layer.

9. The method of claim 1, further comprising the step of applying a second protective layer to said first protective layer.

10. The method of claim 9, said second protective layer comprising a halogenated polymer.

11. The method of claim 10, said halogenated polymer comprising at least about 50% by weight halogen atoms, based upon the total weight of the halogenated polymer taken as 100% by weight.

12. The method of claim 10, wherein said halogenated polymer is a chlorinated polymer.

13. The method of claim 4, further comprising the step of applying a second protective layer to said first protective layer.

14. The method of claim 13, said second protective layer comprising a halogenated polymer and said primer layer comprising an aromatic silane.

15. The method of claim 1, wherein said microelectronic substrate surface is on a substrate 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.

16. The method of claim 8, wherein said heating step yields a primer/first protective layer combination which exhibits less than about 3 mm of lifting when subjected for about 2 hours to etching in an approximately 30-35% by weight aqueous KOH solution having a temperature of about 83-87°

C.

17. The method of claim 8, wherein said heating step yields a primer/first protective layer combination having less than about 0.1 pinholes per cm² of substrate surface.

18. A method of forming a microelectronic structure, said method comprising the steps of:

applying a primer layer to a microelectronic substrate surface; and

applying a first protective layer to said primer layer, said first protective layer including a polymer comprising recurring monomers having the respective formulas

19. The method of claim 18, wherein said polymer comprises at least about 50% by weight of monomer I, based upon the total weight of the polymer taken as 100% by weight.

20. The method of claim 18, wherein said polymer comprises at least about 15% by weight of monomer (II), based upon the total weight of the polymer taken as 100% by weight.

21. The method of claim 18, wherein said polymer comprises from about 50-85% by weight of monomer (I) and from about 15-40% by weight of monomer (II), said percentages by weight being based upon the total weight of the polymer taken as 100% by weight.

22. The method of claim 18, said primer layer comprising an aromatic silane.

23. The method of claim 22, said aromatic silane having the structure

24. The method of claim 18, wherein said substrate surface comprises a plurality of surface hydroxyl groups, said method further comprising the step of heating said primer layer so that said aromatic silane from said primer layer bonds with at least some of said surface hydroxyl groups.

25. The method of claim 18, further comprising the step of heating said first protective layer so that it bonds with said primer layer.

26. The method of claim 18, further comprising the step of applying a second protective layer to said first protective layer.

27. The method of claim 26, said second protective layer comprising a halogenated polymer.

28. The method of claim 27, said halogenated polymer comprising at least about 50% by weight halogen atoms, based upon the total weight of the halogenated polymer taken as 100% by weight.

29. The method of claim 28, wherein said halogenated polymer is a chlorinated polymer.

30. The method of claim 18, wherein said microelectronic substrate surface is on a substrate 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.

31. The method of claim 25, wherein said heating step yields a primer/first protective layer combination which exhibits less than about 3 mm of lifting when subjected for about 2 hours to etching in an approximately 30-35% by weight aqueous KOH solution having a temperature of about 83-87°

C.

32. The method of claim 25, wherein said heating step yields a primer/first protective layer combination having less than about 0.1 pinholes per cm² of substrate.