# US 7,407,554 B2 · Development or removal of block copolymer or PMMA-b-S-based resist using polar supercritical solvent

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- Number: US 7,407,554 B2
- Document ID: US7407554B2
- Status: Granted
- Kind: B2
- Application number: 10/907,688
- Filed: 2005-04-12
- Published: 2006-10-12
- Granted: 2008-08-05
- Earliest claimed: 2005-04-12
- Assignees: International Business Machines Corporation
- Inventors: Matthew E. Colburn; Dmitriy Shneyder; Shahab Siddiqui
- Web page: https://patentgrep.com/patent/US7407554B2

## CPC

- G03F 7/168: {Finishing the coated layer, e.g. drying, baking, soaking}
- G03F 7/325: {Non-aqueous compositions}
- Y10S 438/922: Diffusion along grain boundaries
- Y10S 977/733: Nanodiaphragm
- Y10S 977/734: Fullerenes, i.e. graphene-based structures, such as nanohorns, nanococoons, nanoscrolls or fullerene-like structures, e.g. WS2 or MoS2 chalcogenide nanotubes, planar C3N4, etc.
- 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)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Methods of developing or removing a select region of block copolymer films using a polar supercritical solvent to dissolve a select portion are disclosed. In one embodiment, the polar supercritical solvent includes chlorodifluoromethane, which may be exposed to the block copolymer film using supercritical carbon dioxide (CO2) as a carrier or chlorodiflouromethane itself in supercritical form. The invention also includes a method of forming a nano-structure including exposing a polymeric film to a polar supercritical solvent to develop at least a portion of the polymeric film. The invention also includes a method of removing a poly(methyl methacrylate-b-styrene) (PMMA-b-S) based resist using a polar supercritical solvent.

## Claims

### Claim 1

A method of removing a select portion of a block copolymer, the method comprising the steps of:
exposing the block copolymer to a polar supercritical solvent to dissolve the select portion of the block copolymer, wherein the block copolymer includes a block polystyrene and poly(methyl methacrylate b-styrene) copolymer; and
removing the dissolved portion of the block copolymer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the block copolymer includes a diblock copolymer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the exposing step includes using supercritical carbon dioxide (CO2) as a carrier for the polar supercritical solvent.

### Claim 4 (depends on 1)

The method of claim 1, wherein the exposing step includes exposing in an environment at a temperature of no less than approximately 31° C. and no greater than approximately 80° C., and a pressure of no less than approximately 200 bar and no greater than approximately 300 bar.

### Claim 5 (depends on 1)

The method of claim 1, wherein the polar supercritical solvent includes at least one of: chlorodifluoromethane, methylene chloride, 1,1 dichloroehylene, ethylene dichloride, chloroform, 1,1 dichloroethane, trichloroethylene, chlorobenzene, O-dichlorobenzene, tetrahydrofuran, dibenzyl ether, acetone, methyl ethyl ketone, cyclohexanone, diethyl ketone, acetophenone, methyl isoamyl ketone, isophorone, methyl acetate, ethyl formate, ethyl acetate, diethyl carbonate, diethyl sulfate, 2-ethoxyethyl acetate, 2-nitropropane, nitrobenzene, pyridine, morpholine, analine, N-methyl-2-phyrrolidone and cyclohexylamine.

### Claim 6 (depends on 1)

The method of claim 1, further comprising the step of tuning the polar supercritical solvent to dissolve a select region of the block copolymer.

### Claim 7 (depends on 1)

The method of claim 1, wherein a portion of the block copolymer is crosslinked.

### Claim 8 (depends on 1)

The method of claim 1, wherein the polar supercritical solvent includes chlorodifluoromethane at a temperature of greater than approximately 96.4° C. and a pressure greater than approximately 48.5 bar.

### Claim 9 (depends on 1)

The method of claim 1, wherein the removing step includes removing only a portion of the block copolymer from the block copolymer film.

### Claim 10 (depends on 1)

The method of claim 1, wherein the removing step includes removing the block copolymer adjacent to a dielectric.

### Claim 11 (depends on 1)

The method of claim 1, further comprising the step of transferring a pattern of the block copolymer into an underlying substrate.

### Claim 12 (depends on 11)

The method of claim 11, wherein the transferring step renders the substrate porous.