# US 11,078,337 B2 · High-χ block copolymers for directed self-assembly

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- Number: US 11,078,337 B2
- Document ID: US11078337B2
- Status: Granted
- Kind: B2
- Application number: 15/841,472
- Filed: 2017-12-14
- Published: 2018-06-14
- Granted: 2021-08-03
- Earliest claimed: 2016-12-14
- Assignees: Brewer Science Inc.
- Applicants: Brewer Science Inc.
- Inventors: Daniel Sweat; Kui Xu
- Web page: https://patentgrep.com/patent/US11078337B2

## CPC

- C08G 81/027: {containing polyester or polycarbonate sequences}
- B32B 27/28: comprising synthetic resins not wholly covered by any one of the sub-groups {B32B27/30 - B32B27/42}
- C08F 293/00: Macromolecular compounds obtained by polymerisation on to a macromolecule having groups capable of inducing the formation of new polymer chains bound exclusively at one or both ends of the starting macromolecule (on to polymers modified by introduction of unsaturated end groups C08F290/02)
- C08F 293/005: {using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent}
- C08G 63/08: Lactones or lactides
- C08G 65/40: from phenols (I) and other compounds (II), e.g. OH-Ar-OH + X-Ar-X, where X is halogen atom, i.e. leaving group
- C08G 81/02: at least one of the polymers being obtained by reactions involving only carbon-to-carbon unsaturated bonds
- C08L 53/00: Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
- C08L 87/00: Compositions of unspecified macromolecular compounds, obtained otherwise than by polymerisation reactions only involving unsaturated carbon-to-carbon bonds
- C08L 87/005: {Block or graft polymers not provided for in groups C08L1/00 - C08L85/04}
- G03F 7/0002: {Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping}
- G03F 7/16: Coating processes; Apparatus therefor (applying coatings to base materials in general B05; applying photosensitive compositions to base for photographic purposes G03C1/74)
- G03F 7/20: Exposure; Apparatus therefor (photographic printing apparatus for making copies G03B27/00)
- G03F 7/327: {Non-aqueous alkaline compositions, e.g. anhydrous quaternary ammonium salts}
- H10P 76/20: of masks comprising organic materials
- C08F 2438/03: Use of a di- or tri-thiocarbonylthio compound, e.g. di- or tri-thioester, di- or tri-thiocarbamate, or a xanthate as chain transfer agent, e.g . Reversible Addition Fragmentation chain Transfer [RAFT] or Macromolecular Design via Interchange of Xanthates [MADIX]
- C08L 2201/56: Non-aqueous solutions or dispersions
- C08L 2203/20: use in electrical or conductive gadgets
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- 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)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The present invention is broadly concerned with novel directed self-assembly compositions, processes utilizing those compositions, and the resulting structures that are formed. The composition comprises a block copolymer of polystyrene and a polymethylmethacrylate block with polylactic acid side chains (“PS-b-P(MMA-LA)”). The block copolymer is capable of crosslinking and micro-phase separating into lines and spaces measuring about 10-nm or smaller with sub-20 nm L0 capability. Additionally, PS-b-P(MMA-LA) can be thermally annealed without a top-coat for simpler processing than the prior art. The polylactic acid side chains also increase the etch rate of the poly(methylmethacrylate) block when exposed to oxygen plasma, as well as lower the Tg.

## Claims

### Claim 1

A method of forming a microelectronic structure, said method comprising:
providing a stack comprising:
a substrate having a surface; and
one or more optional intermediate layers on said substrate surface;
applying a composition to said intermediate layers, if present, or to said substrate surface, if no intermediate layers are present, said composition comprising a block copolymer comprising a first block and a second block, said first block being a copolymer that includes recurring monomers comprising lactic acid moieties that are present as side chains on said recurring monomers; and
causing said composition to self-assemble into a self-assembled layer, wherein said self-assembled layer comprises a first self-assembled region and a second self-assembled region different from said first self-assembled region.

### Claim 2 (depends on 1)

The method of claim 1, wherein said recurring monomers are selected from the group consisting of 2-hydroxyethyl methacrylate monomers, 3-hydroxypropyl methacrylate, and mixtures thereof, and said lactic acid moieties are side chains on said recurring monomers.

### Claim 3 (depends on 1)

The method of claim 1, wherein said first block further comprises recurring monomers of methyl methacrylate.

### Claim 4 (depends on 1)

The method of claim 1, wherein said second block comprises recurring monomers selected from the group consisting of styrene, other styrene-containing monomers, alkyl vinylbenzyl ethers, vinylbenzyl ethers, vinylbiphenyl, vinylbenzocyclobutene, vinylnaphthalene, vinylphenanthrene, vinylanthracene, vinylanisole, vinylpyridine, vinylnaphthalate, and mixtures thereof.

### Claim 5 (depends on 1)

The method of claim 1, said first block being a random copolymer.

### Claim 6 (depends on 1)

The method of claim 1, wherein said first block comprises less than about 5% by weight methyl methacrylate side chains, based upon the total weight of the first block taken as 100% by weight.

### Claim 7 (depends on 1)

The method of claim 1, wherein said causing comprises heating said composition to at least about the glass transition temperature of said block copolymer, said self-assembling occurring during said heating.

### Claim 8 (depends on 1)

The method of claim 1, wherein said stack comprises an intermediate layer selected from the group consisting of bottom anti-reflective coatings, neutral brush layers, hardmask neutral layers, hardmasks, spin-on carbon layers, etch block layers, and imaging layers.

### Claim 9 (depends on 1)

The method of claim 1, wherein said substrate is a semiconductor substrate.

### Claim 10 (depends on 1)

The method of claim 1, further comprising removing said second self-assembled region to yield a pattern in said self-assembled layer.

### Claim 11 (depends on 1)

The method of claim 1, wherein an intermediate layer is present, said intermediate layer comprising a pre-pattern comprising a plurality of raised features, said raised features being spaced apart and each being defined by respective sidewalls and a top surface, wherein said self-assembling composition is applied directly on top of said intermediate layer in spaces between said raised features.

### Claim 12 (depends on 11)

The method of claim 11, wherein said plurality of raised features are formed by:
applying a photosensitive composition to form an imaging layer on any other intermediate layer, if present, or on said substrate surface, if no other intermediate layers are present; and
patterning said imaging layer to yield said pre-pattern, before applying said composition to said imaging layer.

### Claim 13 (depends on 1)

The method of claim 1, wherein at least one intermediate layer is present, said intermediate layer being selected from the group consisting of hardmask layers and neutral layers, and wherein said intermediate layer comprises a surface having surface-modified regions and non-modified regions, said first and second self-assembled regions being adjacent said non-modified regions.

### Claim 14 (depends on 13)

The method of claim 13, wherein, before applying said composition to said intermediate layer, said surface-modified regions and non-modified regions are formed by:
forming an imaging layer on said intermediate layer;
patterning said imaging layer to yield a pre-pattern, wherein said patterning comprises selectively removing portions of said imaging layer to uncover portions of said intermediate layer;
contacting said uncovered portions of intermediate layer with a developer or solvent to yield said surface-modified regions; and
removing remaining portions of said imaging layer from said intermediate layer to yield said non-modified regions.

### Claim 15 (depends on 13)

The method of claim 13, wherein, before applying said composition to said intermediate layer, said surface-modified regions and non-modified regions are formed by selectively exposing said intermediate layer to radiation.

### Claim 16 (depends on 1)

The method of claim 1, wherein said causing is carried out after said applying, without applying a further layer being formed on, or a second composition being applied to, said composition.

### Claim 17 (depends on 1)

The method of claim 1, wherein said lactic acid moieties have respective number average molecular weights of from about 100 g/mol to about 5,000 g/mol.