# US 8,771,927 B2 · Acid-etch resistant, protective coatings

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- Number: US 8,771,927 B2
- Document ID: US8771927B2
- Status: Granted
- Kind: B2
- Application number: 12/718,516
- Filed: 2010-03-05
- Published: 2011-07-14
- Granted: 2014-07-08
- Earliest claimed: 2009-04-15
- Assignees: Brewer Science Inc.
- Applicants: Tingji Tang; Gu Xu; Xing-Fu Zhong; Wenbin Hong; Tony D. Flaim; Kimberly Yess; Ramachandran K. Trichur
- Inventors: Tingji Tang; Gu Xu; Xing-Fu Zhong; Wenbin Hong; Tony D. Flaim; Kimberly Yess; Ramachandran K. Trichur
- Web page: https://patentgrep.com/patent/US8771927B2

## CPC

- B81C 1/00801: {Avoid alteration of functional structures by etching, e.g. using a passivation layer or an etch stop layer (B81C1/00595, B81C1/00468 take precedence)}
- C08G 61/08: of carbocyclic compounds containing one or more carbon-to-carbon double bonds in the ring
- H10P 50/692: {characterised by their composition, e.g. multilayer masks or materials}
- H10P 76/2041: {Photolithographic processes}
- B81C 2201/053: Depositing a protective layers
- C08G 2261/3324: derived from norbornene
- C08G 2261/418: Ring opening metathesis polymerisation [ROMP]
- G03F 7/033: the binders being polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers
- G03F 7/094: {Multilayer resist systems, e.g. planarising layers}
- Y10T 428/31645: Next to addition polymer from unsaturated monomers
- Y10T 428/31667: Next to addition polymer from unsaturated monomers, or aldehyde or ketone condensation product
- Y10T 428/31692: Next to addition polymer from unsaturated monomers
- Y10T 428/31855: Of addition polymer from unsaturated monomers
- Y10T 428/31909: Next to second addition polymer from unsaturated monomers
- B81C: PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS (making microcapsules or microballoons B01J13/02; processes or apparatus specially adapted for the manufacture or treatment of piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/01)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

New compositions and methods of using those compositions as protective layers during the production of semiconductor and MEMS devices are provided. The compositions comprise a cycloolefin copolymer dispersed or dissolved in a solvent system, and can be used to form layers that protect a substrate during acid etching and other processing and handling. The protective layer can be photosensitive or non-photosensitive, and can be used with or without a primer layer beneath the protective layer. Preferred primer layers comprise a basic polymer in a solvent system.

## Claims

### Claim 1

A method of forming a microelectronic structure, said method comprising:
providing a substrate having a surface;
optionally forming a primer layer on said substrate surface;
forming a protective layer on said primer layer, if present, or on said substrate surface if no primer layer is present, to yield a protected stack, said protective layer being formed from a composition comprising a cycloolefin copolymer of recurring cycloolefin monomers and monomers of
where:
- - - - - is a single bond; and
each R4 is individually selected from the group consisting of —H and alkyl groups;
said cycloolefin copolymer being dissolved or dispersed in a solvent system, wherein said protective layer would experience very little or no acid etchant penetration if etched by an approximately 48% by weight aqueous HF solution, having a temperature of about 20-25° C., for about 1-2 hours; and
subjecting said protected stack to an acidic etching process.

### Claim 2 (depends on 1)

The method of claim 1, further comprising subjecting said protected stack to further processing steps prior to subjecting said stack to said acidic etching process.

### Claim 3 (depends on 1)

The method of claim 1, further comprising exposing said protective layer to broadband UV radiation.

### Claim 4 (depends on 3)

The method of claim 3, wherein said protective layer is photosensitive and said exposing yields exposed portions of said protective layer, said exposed portions comprising a crosslinked cycloolefin copolymer.

### Claim 5 (depends on 1)

The method of claim 1, wherein said acidic etching process comprises etching with an etchant selected from the group consisting of aqueous HF, HF vapor, HF/H2O vapor, HF/alcohol vapor, HCl, phosphoric acid, HCl/HNO3, buffered oxide etchant (“BOE”), HF/HNO3/acetic acid, concentrated H2SO4, concentrated HNO3, and mixtures of the foregoing.

### Claim 6 (depends on 1)

The method of claim 1, wherein said cycloolefin copolymer is formed from the polymerization of a cyclic olefin selected from the group consisting of
and combinations of the foregoing,
where:
each R1 and R2 is individually selected from the group consisting of —H, and alkyl groups; and
each R3 is individually selected from the group consisting of —H, substituted and unsubstituted aryl groups, alkyl groups, cycloalkyl groups, aralkyl groups, ester groups, ether groups, acetyl groups, alcohols, aldehyde groups, ketones, nitriles, and combinations thereof.

### Claim 7 (depends on 1)

The method of claim 1, wherein said cycloolefin recurring monomers are selected from the group consisting of:
and combinations of the foregoing,
where:
each R1 and R2 is individually selected from the group consisting of —H, and alkyl groups; and
each R3 is individually selected from the group consisting of —H, substituted and unsubstituted aryl groups, alkyl groups, cycloalkyl groups, aralkyl groups, ester groups, ether groups, acetyl groups, alcohols, aldehyde groups, ketones, nitriles, and combinations thereof.

### Claim 8 (depends on 1)

The method of claim 1, wherein a primer layer is formed on said substrate surface.

### Claim 9 (depends on 8)

The method of claim 8, wherein said primer layer is formed from composition comprising a basic polymer in a solvent system.

### Claim 10 (depends on 9)

The method of claim 9, wherein said basic polymer is selected from the group consisting of polyvinyl pyridine, polymelamines, polyethylenimine, triazine-containing copolymers, styrene maleimide resin, poly(4-vinyl pyridine-co-styrene), and poly(2-vinyl pyridine-co-styrene).

### Claim 11 (depends on 1)

The method of claim 1, wherein said substrate is selected from the group consisting of thermal oxide substrates, 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.

### Claim 12 (depends on 1)

The method of claim 1, wherein said protective layer exhibits less than about 0.1 pinholes per cm3 of said substrate when subjected to said acidic etching process.

### Claim 13 (depends on 1)

The method of claim 1, wherein said cycloolefin copolymer has a glass transition temperature (Tg) of from about 60° C. to about 200° C.

### Claim 14

A method of forming a microelectronic structure, said method comprising:
providing a substrate having a surface;
optionally forming a primer layer on said substrate surface;
forming a protective layer on said primer layer, if present, or on said substrate surface if no primer layer is present, to yield a protected stack, said protective layer being formed from a composition comprising a cycloolefin copolymer of recurring cycloolefin monomers and monomers of
where:
- - - - - is a single bond; and
each R4 is individually selected from the group consisting of —H and alkyl groups;
wherein said cycloolefin copolymer and a photosensitive crosslinking agent are dissolved or dispersed in a solvent system; and
subjecting said protected stack to an acidic etching process.

### Claim 15 (depends on 14)

The method of claim 14, wherein said crosslinking agent is an azide-based photosensitive crosslinking agent.

### Claim 16 (depends on 14)

The method of claim 14, wherein said cycloolefin copolymer has a glass transition temperature (Tg) of from about 60° C. to about 200° C.