Gradient block copolymers for directed self-assembly

Patent metadata

Field	Value
Publication number	US-10961383-B2
Application number	US-201816133051-A
Country	US
Kind code	B2
Filing date	Sep 17, 2018
Priority date	Feb 1, 2018
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

Novel block copolymers (“BCPs”) having non-random distributions of comonomers within at least one of the blocks and methods of using those BCPs in directed self-assembly (“DSA”) processes are provided. The non-random (e.g., gradient-creating) distributions can be customized in order to concentrate the desired comonomer properties in predetermined areas of the BCP. These BCPs can achieve perpendicular orientation with simple annealing and offer superior long-range ordering and lower defectivity when compared to prior art BCPs. These BCPs can be incorporated into compositions that simultaneously offer the benefits of high-χ and rapid thermal-annealing kinetics while maintaining similar or improved guide process windows when compared to prior art BCPs.

First claim

We 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 one or more 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, at least one of said first and second blocks comprising:
a junction region comprising a first plurality of monomers and positioned nearest the other of said first and second blocks;
an end region comprising a second plurality of monomers and positioned farthest from the other of said first and second blocks; and
an intermediate region comprising a third plurality of monomers and positioned intermediate said junction region and said end region, said intermediate region further comprising a second monomer selected from the group consisting of styrene, methyl styrenes, vinylbiphenyls, tert-butylstyrene, dimethyl styrenes, trimethylstyrene, methoxy styrene, fluorostyrenes, difluorostyrenes, pentafluorostyrene, trifluoromethylstyrene, benzhydryl styrene, vinylbenzocyclobutene, vinyl naphthalenes, vinylphenanthrenes, vinylthiophene, vinylanisole, vinylanthracene, vinylpyridines, alkyl styrenes, alkoxy styrenes, alkyl vinylbenzyl ethers, vinylbenzyl ether monomers, trimethylsilylstyrene, 9-(4-vinylbenzyl)-9H-carbazole, and combinations thereof, wherein:
(I) said end region includes a property-adjusting monomer at a concentration that is greater than the property-adjusting monomer concentration in the intermediate region and greater than the property-adjusting monomer concentration in the junction region, said property-adjusting monomer is selected from the group consisting of 4-alkyl styrenes, 3-alkyl styrenes, 4-alkoxy styrenes, 3-alkoxy styrenes, 1-(4-tolyloxymethyl)-4-vinylbenzene, alkyl vinylbenzyl ethers, vinylbenzyl ether monomers, 2-methyl styrene, 3-vinylbiphenyl, 4-tert-butylstyrene, 2,4-dimethyl styrene, 3,4-dimethyl styrene, 2,5-dimethyl styrene, 3,5-dimethyl styrene, 2,4,6-trimethylstyrene, 4-methoxy styrene, 4-fluorostyrene, 3-fluorostyrene, 2-fluorostyrene, 2,3-difluorostyrene, 2,4-difluorostyrene, pentafluorostyrene, 4-vinylbiphenyl, 4-benzhydrylstyrene, 4-vinylbenzocyclobutene, 1-vinyl naphthalene, 2-vinyl naphthalene, 2-vinylphenanthrene, 9-vinylphenanthrene, 2-vinylthiophene, 9-vinylanthracene, vinylbenzocyclobutene, 1-vinylnapthlalate, 2-vinylnapthalate, 2-vinylanthracene, 9-vinylanthracene, 9-vinylphenantrene, 4-trimethylsilylstyrene, and combinations thereof;
(II) said intermediate region includes said property-adjusting monomer at a concentration that is lower than the property-adjusting monomer concentration in the end region; and
(III) said junction region:
lacks said property-adjusting monomer; or
includes said property-adjusting monomer at a concentration that is lower than said property-adjusting monomer concentration in the end region and lower than said property-adjusting monomer concentration in the intermediate region; 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.

2. The method of claim 1 , wherein the end region (I) comprises only said property-adjusting monomer.

3. The method of claim 1 , wherein the junction region (III) comprises a second monomer different from said property-adjusting monomer.

4. The method of claim 1 , wherein said second monomer present in the intermediate region (II) is greater than the concentration of the second monomer in the end region (I).

5. The method of claim 1 , wherein said intermediate region has a length extending from the end region and the junction region, and the property-adjusting monomer concentration decreases gradiently across that length.

6. The method of claim 1 , wherein the other of said first and second blocks is a homopolymer.

7. The method of claim 1 , wherein the other of said first and second blocks comprises:
a second junction region comprising a fourth plurality of monomers and positioned nearest the at least one of said first and second blocks;
a second end region comprising a fifth plurality of monomers and positioned farthest from the at least one of said first and second blocks; and
a second intermediate region comprising a sixth plurality of monomers and positioned intermediate said second junction region and said second end region, wherein:
(IV) one of said second junction, second intermediate, and second end regions includes a third monomer at a concentration that is greater than the respective concentrations of said third monomer in each of the other two of said second junction, second intermediate, and second end regions;
(V) another of said second junction, second intermediate, and second end regions different than the region of (IV) includes said third monomer at a concentration that is lower than the third monomer concentration in the region of (IV); and
(VI) another of said second junction, second intermediate, and second end regions different than the regions of (IV) and (V) that:
lacks said third monomer; or
includes said third monomer at a concentration that is lower than said third monomer concentration in the region of (IV) and lower than said third monomer concentration in the region of (V).

8. The method of claim 7 , wherein:
(IV) is said second junction region, (V) is said second intermediate region, and (VI) is said second end region; or
(IV) is said second end region, (V) is said second intermediate region, and (VI) is said second junction region.

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

10. 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.

11. The method of claim 10 , 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.

12. The method of claim 11 , wherein said patterning comprises:
exposing said imaging layer to radiation to yield exposed and unexposed portions of said imaging layer; and
contacting said imaging layer with a developer so as to remove one of said exposed or unexposed portions.

13. 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.

14. 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-patt

Assignees

• Brewer Science Inc

Inventors

• Xu Kui
• Daugherty Jr Richard Elsworth
• Sweat Daniel Patrick
• Hockey Mary Ann
• Calderas Eric
• Bennett Megan

Classifications

• H10P76/20

  of masks comprising organic materials · CPC title

• C08F293/005 Primary

  using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent · CPC title

• C08G63/06

  derived from hydroxycarboxylic acids · CPC title

• C08F2438/03

  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] · CPC title

• C08F20/26

  Esters containing oxygen in addition to the carboxy oxygen · CPC title