# US 8,785,113 B2 · Method and materials for reverse patterning

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- Number: US 8,785,113 B2
- Document ID: US8785113B2
- Status: Granted
- Kind: B2
- Application number: 13/386,502
- Filed: 2010-06-22
- Published: 2012-05-17
- Granted: 2014-07-22
- Earliest claimed: 2009-07-23
- Assignees: Dow Corning Corporation
- Applicants: Michael L. Bradford; Eric Scott Moyer; Sheng Wang
- Inventors: Michael L. Bradford; Eric Scott Moyer; Sheng Wang
- Web page: https://patentgrep.com/patent/US8785113B2

## CPC

- H10P 76/4085: {characterised by the processes involved to create the masks}
- G03F 7/405: {Treatment with inorganic or organometallic reagents after imagewise removal}
- H10P 14/6686: {the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane}
- H10P 14/6922: {the material containing Si, O and at least one of H, N, C, F or other non-metal elements, e.g. SiOC, SiOC:H or SiONC}
- C08G 77/04: Polysiloxanes
- 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)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

A silsesquioxane resin is applied on top of the patterned photo-resist and cured to produce a cured silsesquioxane resin on top of the pattern surface. Subsequently, a reactive ion etch recipe containing CF4 to “etch back” the silicon resin to the top of the photoresist material, exposing the entire top surface of the organic based photoresist. Then, a second reactive ion etch recipe containing O2 to etch away the organic photoresist. The result is a silicon resin film with via holes with the size and shape of the post that were patterned into the photoresist. Optionally, the new pattern can be transferred into the underlying layer(s).

## Claims

### Claim 1

A method for forming a reverse pattern on a substrate wherein the method comprises
(I) applying a coating composition over a first patterned material wherein the coating composition comprises
(i) a silsesquioxane resin comprised of the units
(MeSiO(3-x)/2(OR′)x)m
(RSiO(3-x)/2(OR′)x)n
(R1SiO(3-x)/2(OR′)x)o
(SiO(4-x)/2(OR′)x)p
(Ph(CH2)sSiO(3-x)/2(OR′)x)q
where Ph is a phenyl group, Me is a methyl group; R′ is hydrogen atom or a hydrocarbon group having from 1 to 4 carbon atoms; R is a reactive organic group selected from groups containing epoxy functionality and groups containing acryloxy functionality, R1 is a hydrophilic group; and s has a value of 0, 1, 2, 3, or 4; x has a value of 0, 1 or 2; and in the resin m has a value of 0.2 to 0.95, n has a value of 0.01 to 0.5; o has a value of 0 to 0.20; p has a value of 0 to 0.75; q has a value of 0 to 0.5 and m+n+o+p+q≈1; and
(ii) a solvent for carrying the resin without dissolving the first patterned material; and
(iii) an activator;
(III) curing the coating composition to produce a cured silicon coating on top of the first patterned material covering the entire pattern;
(IV) partially removing the cured silicon coating to expose the top surface of the first patterned material;
(V) removing the first patterned material thereby forming a second patterned in the cured silicon coating; and
(VI) optionally, further transferring the second pattern onto any underlayer;
wherein the first patterned material is formed by a method consisting of applying a photoresist to the substrate and patterning the applied photoresist to form the first patterned material.

### Claim 2 (depends on 1)

The method as claimed in claim 1 where m has a value of 0.5 to 0.90, n has a value of 0.05 to 0.30; o has a value of 0 to 0.20; p has a value of 0 to 0.30; and q has a value of 0 to 0.15.

### Claim 3 (depends on 1)

The method as claimed in claim 1 wherein R is an epoxy group having the formula —R2OCH2CH(O)CH2, where R2 is hydrocarbon group having 1 to 4 carbon atoms or a polyether group or —CH2CH2—(C6H9(O)).

### Claim 4 (depends on 3)

The method as claimed in claim 3 wherein the activator is selected from a thermal acid generator, a photoacid generator or an amine crosslinker.

### Claim 5 (depends on 1)

The method as claimed in claim 1 wherein R is 3-glycidoxypropyl group.

### Claim 6 (depends on 1)

The method as claimed in claim 1 wherein R is a 2-(3,4-epoxycyclohexyl) group.

### Claim 7 (depends on 1)

The method as claimed in claim 1 wherein R is an acryloxy functionality having the formula CH2═C(R3)COOR4—, where R3 is hydrogen atom or a methyl group and R4 is hydrocarbon group having 1 to 4 carbon atoms or a polyether group.

### Claim 8 (depends on 7)

The method as claimed in claim 7 wherein the activator is selected from a free radical thermal initiator or a photo radical initiator.

### Claim 9 (depends on 1)

The method as claimed in claim 1 wherein R is a methacryloxypropyl group.

### Claim 10 (depends on 1)

The method as claimed in claim 1 wherein R is an acryloxypropy group.

### Claim 11 (depends on 1)

The method as claimed in claim 1 wherein R1 is selected from substituted phenyl groups, ester groups, polyether groups, and mercapto groups.

### Claim 12 (depends on 11)

The method as claimed in claim 11 wherein the solvent is selected from -methoxy-2-propanol, 4-methyl-2-pentanol, propylene glycol monomethyl ethyl acetate, γ-butyrolactone, and cyclohexanone.

### Claim 13 (depends on 1)

The method as claimed in claim 1 wherein the coating composition is thermally cured by heating at 80° C. to 450° C. for 0.1 to 60 minutes.

### Claim 14 (depends on 1)

The method as claimed in claim 1 wherein the coating composition is radiation cured by exposing the coating composition to a radiation source selected from UV, X-ray, e-beam, or EUV.

### Claim 15 (depends on 1)

The method as claimed in claim 1 wherein the cured silicon coating composition is partially removed using a reactive ion etch containing CF4.

### Claim 16 (depends on 1)

The method as claimed in claim 1 wherein the first patterned material is removed by a reactive ion etch containing O2.