Photoresist undercoat-forming material and patterning process

• US 20060019195A1
• Filed: 09/30/2004
• Published: 01/26/2006
• Est. Priority Date: 10/03/2003
• Status: Active Grant

• Current Assignee: Shin-Etsu Chemical Company Limited
• Original Assignee: Shin-Etsu Chemical Company Limited
• Inventors: Hatakeyama, Jun, Watanabe, Satoshi
• Granted Patent: US 7,303,855 B2
• Time in Patent Office: Days
• US Class Current: 430/271.100
• 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 7/091 characterised by antireflection means or light filtering or absorbing means, e.g. anti-halation, contrast enhancement
• CPC Class Codes: Y10S 430/115 Cationic or anionic
• CPC Class Codes: Y10S 430/12 Nitrogen compound containing
• CPC Class Codes: Y10S 430/121 Nitrogen in heterocyclic ring
• CPC Class Codes: Y10S 430/122 Sulfur compound containing
• CPC Class Codes: Y10S 430/126 Halogen compound containing

Abstract

An undercoat-forming material comprising a novolak resin having a fluorene or tetrahydrospirobiindene structure, an organic solvent, an acid generator, and a crosslinker, optionally combined with an intermediate layer having an antireflective effect, has an absorptivity coefficient sufficient to provide an antireflective effect at a thickness of at least 200 nm and a high etching resistance as demonstrated by slow etching rates with CF₄/CHF₃ and Cl₂/BCl₃ gases for substrate processing.

Claims

1. (canceled)

2. An undercoat-forming material comprising a novolak resin having a fluorene or tetrahydrospirobiindene structure comprising recurring units of the general formula (1a) or (1b):

3. The undercoat-forming material of claim 2, further comprising an organic solvent and an acid generator.

4. The undercoat-forming material of claim 2, further comprising a crosslinker.

5. A patterning process comprising the steps of:

applying the undercoat-forming material of claim 2 onto a processable substrate to form an undercoat layer,

applying a photoresist composition onto the undercoat layer to form a photoresist layer,

exposing the photoresist layer in a predetermined region to radiation,

developing the photoresist layer with a developer to form a photoresist pattern, and

processing the undercoat layer and the substrate through the patterned photoresist layer as a mask, by means of a dry etching apparatus.

6. The patterning process of claim 5, wherein said photoresist composition comprises a silicon atom-bearing polymer, and the processing step includes dry etching the undercoat layer through the photoresist layer as a mask with an oxygen-based etching gas.

7. A patterning process comprising the steps of:

applying the undercoat-forming material of claim 2 onto a processable substrate to form an undercoat layer,

applying a silicon atom-containing intermediate layer over the undercoat layer,

applying a photoresist composition onto the intermediate layer to form a photoresist layer,

exposing the photoresist layer in a predetermined region to radiation,

developing the photoresist layer with a developer to form a photoresist pattern,

processing the intermediate layer through the patterned photoresist layer as a mask,

removing the patterned photoresist layer, and

processing the undercoat layer and then the substrate through the processed intermediate layer as a mask,

the processing steps using a dry etching apparatus.

8. The patterning process of claim 7, wherein said photoresist composition comprises a silicon atom-free polymer, and the step of processing the undercoat layer includes dry etching with an oxygen-based etching gas.

9. The undercoat-forming material of claim 2, wherein the novolak resin is one obtained by condensation reacting with an aldehyde (A) a phenol having a fluorene structure selected from the group consisting of 4,4′

-(9H-fluoren-9-ylidene)bisphenol, 2,2′

-dimethyl-4,4′

-(9H-fluoren-9-ylidene)bisphenol, 2,2′

-diallyl-4,4′

-(9H-fluoren-9-ylidene)bisphenol, 2,2′

-difluoro-4,4′

-(9H-fluoren-9-ylidene)bisphenol, 2,2′

-diphenyl-4,4′

-(9H-fluoren-9-ylidene)bisphenol, and 2,2′

-dimethoxy-4,4′

-(9H-fluoren-9-ylidene)bisphenol, and/or (B) a phenol having a tetrahydrospirobiindene structure selected from the group consisting of 2,3,2′

,3′

-tetrahydro-(1,1′

)-spirobiindene-6,6′

-diol, 3,3,3′

,3′

-tetramethyl-2,3,2′

,3′

-tetrahydro-(1,1′

)-spirobiindene-6,6′

-diol, 3,3,3′

,3′

,4,4′

-hexamethyl-2,3,2′

,3′

-tetrahydro-(1,1′

)-spirobiindene-6,6′

-diol, 2,3,2′

,3′

-tetrahydro-(1,1′

)-spirobiindene-5,5′

-diol, and 5,5′

-dimethyl-3,3,3′

,3′

-tetramethyl-2,3,2′

,3′

-tetrahydro-(1,1′

)-spirobiindene-6,6′

-diol, and optionally with (C) a copolymerizable phenol selected from the group consisting of phenol, o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, 2-t-butylphenol, 3-t-butylphenol, 4-t-butylphenol, 2-phenylphenol, 3-phenylphenol, 4-phenylphenol, 3,5-diphenylphenol, 2-naphthylphenol, 3-naphthylphenol, 4-naphthylphenol, 4-tritylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, catechol, 4-t-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-t-butyl-5-methylphenol, pyrogallol, thymol, and isothymol, and/or (D) a copolymerizable monomer selected from the group consisting of 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol;

dihydroxynaphthalenes, methyl 3-hydroxy-naphthalene-2-carboxylate, indene, hydroxyindene, benzofuran, hydroxyanthracene, acenaphthylene, biphenyl, bisphenol, trisphenol, dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, norbornadiene, 5-vinylnorborn-2-ene, α

-pinene, β

-pinene, and limonene, so that the phenol (A) and/or (B), additional phenol (C), and copolymerizable monomer (D) are combined in such proportion as to meet a molar ratio [A+B]/[A+B+C+D]=0.1 to 1.0.

10. The undercoat-forming material of claim 2, wherein the novolak resin is modified by introducing a fused aromatic or cycloaliphatic substituent group into the novolak resin phenol at the ortho or para position.

11. The undercoat-forming material of claim 9, wherein the novolak resin as condensed is modified by introducing a fused aromatic or cycloaliphatic substituent group into the novolak resin phenol at the ortho or para position, said substituent group being at least one selected from the group consisting of:

12. A patterning process comprising the steps of:

applying an undercoat-forming material comprising a novalak resin having a fluorene or tetrahydrospirobiindene structure, onto a processable substrate to form an undercoat layer,

applying a photoresist composition onto the undercoat layer to form a photoresist layer,

exposing the photoresist layer in a predetermined region to radiation,

developing the photoresist layer with a developer to form a photoresist pattern, and

processing the undercoat layer and the substrate through the patterned photoresist layer as a mask, by means of a dry etching apparatus.

13. The patterning process of claim 12, wherein said photoresist composition comprises a silicon atom-bearing polymer, and the processing step includes dry etching the undercoat layer through the photoresist layer as a mask with an oxygen-based etching gas.

14. A patterning process comprising the steps of:

applying an undercoat-forming material comprising a novalak resin having a fluorene or tetrahydrospirobiindene structure, onto a processable substrate to form an undercoat layer,

applying a silicon atom-containing intermediate layer over the undercoat layer,

applying a photoresist composition onto the intermediate layer to form a photoresist layer,

exposing the photoresist layer in a predetermined region to radiation,

developing the photoresist layer with a developer to form a photoresist pattern,

processing the intermediate layer through the patterned photoresist layer as a mask,

removing the patterned layer, and

processing the undercoat layer and then the substrate through the processed intermediate layer as a mask,

the processing steps using a dry etching apparatus.

15. The patterning process of claim 14, wherein said photoresist composition comprises a silicon atom-free polymer, and the step of processing the undercoat layer includes dry etching with an oxygen-based etching gas.