Orientation control materials for block copolymers used in directed self-assembly applications

Patent metadata

Field	Value
Publication number	US-9556353-B2
Application number	US-201414526884-A
Country	US
Kind code	B2
Filing date	Oct 29, 2014
Priority date	Oct 29, 2014
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

An orientation control layer (OCL) for self-assembly of block copolymers comprises a random copolymer comprising a first repeat unit having an ethylenic backbone functional group and a side chain aromatic ring, a second repeat unit comprising an ethylenic backbone functional group and a side chain polycarbonate, and a third repeat unit comprising an ethylenic backbone functional group and a side chain ester or amide bearing an active group capable of forming a covalent bond with a substrate surface (e.g., a silicon wafer). The OCLs are neutral wetting to block copolymers having a high Flory-Huggins interaction parameter chi (χ) (“high-chi” block copolymers) such as a block copolymer comprising a polystyrene block and a polycarbonate block. The neutral OCL wetting properties allow for formation of lamellar domain patterns of the self-assembled high-chi block copolymers to be oriented perpendicular to the OCL surface.

First claim

What is claimed is:

1. A polymer, comprising:
i) a divalent first repeat unit of formula (A-1):

wherein
R x is a monovalent radical selected from the group consisting of H, methyl, ethyl, and trifluoromethyl (*—CF 3 ), and
R b is a monovalent radical comprising an aromatic ring;
ii) a divalent second repeat unit of formula (A-2):

wherein
a′ represents numbers of repeat units enclosed by the parentheses and has an average value of 1 or more,
E 1 is a monovalent end group independently selected from the group consisting of hydrogen and monovalent radicals comprising 1-10 carbons,
each J′ is an independent monovalent radical selected from the group consisting of hydrogen and monovalent radicals comprising 1 to 10 carbons,
L′ is an independent divalent radical linking group comprising 1 to 10 carbons,
each R a is an independent monovalent radical selected from the group consisting of hydrogen, methyl, and ethyl,
R y is a monovalent radical selected from the group consisting of H, methyl, ethyl, and trifluoromethyl (*—CF 3 ), and
X′ is an independent divalent radical selected from the group consisting of *—O—*, *—S—*, *—N(H)—*, and *—N(R″)—*, wherein R″ is a monovalent radical comprising 1 to 6 carbons; and
iii) a divalent third repeat unit of formula (A-3):

wherein
R z is a monovalent radical selected from the group consisting of H, methyl, ethyl, and trifluoromethyl (*—CF 3 ),
L″ is an independent divalent linking group comprising 1 to 10 carbons, and
K′ is a monovalent radical selected from the group consisting of active carboxylic ester groups, halide groups, sulfonate esters, and groups containing an epoxide group, wherein K′ is capable of reacting with a nucleophile to form a covalent bond;
and wherein the first repeat unit, the second repeat unit, and the third repeat of the polymer are linked covalently in a random distribution.

2. The polymer of claim 1 , wherein the polymer is suitable for use as an orientation control layer used in a lithographic process that includes self-assembly of a block copolymer disposed on the orientation control layer, wherein the block copolymer comprises a polycarbonate block.

3. The polymer of claim 1 , wherein the polymer comprises the first repeat unit and the second repeat unit in a first repeat unit: second repeat unit mole ratio between 24:76 and 73:27 based on total moles of the first repeat unit and the second repeat unit.

4. The polymer of claim 1 , wherein L′-X′ is selected from the group consisting of

and combinations thereof, wherein the starred bond of the carbonyl group of L′-X′ is linked to carbon 1 of formula (A-2).

5. The polymer of claim 1 , wherein the second repeat unit is selected from the group consisting of

and
combinations thereof, wherein a′ has an average value of about 1 to about 40 and R f is a monovalent radical comprising 1 to 10 carbons.

6. The polymer of claim 1 , wherein the first repeat unit is a styrene repeat unit and the second repeat unit is a trimethylene carbonate repeat unit.

7. The polymer of claim 1 , wherein R x is hydrogen and R b is phenyl of formula (A-1).

8. The polymer of claim 1 , wherein R z is methyl and L″-K′ is

of formula (A-3).

9. A method, comprising:
forming an initial layer disposed on a surface of a substrate, the initial layer comprising the polymer of claim 1 and a solvent, the substrate comprising a nucleophilic group capable of reacting with K′ of the third repeat unit to form a derivative of the polymer, the derivative comprising a divalent linking group K″ covalently linked to the substrate; and
treating the initial layer to remove the solvent, thereby forming an article (modified substrate) comprising an orientation control layer disposed on the surface of the substrate, wherein i) the orientation control layer comprises the derivative of the polymer comprising the linking group K″ covalently linked to the substrate and ii) the orientation control layer is suitable for a lithographic process that includes self-assembly of a block copolymer disposed on the orientation control layer, the block copolymer comprising a polycarbonate block.

10. The method of claim 9 , wherein the initial layer comprises a member of the group consisting of thermal acid generators (TAGs), photo-acid generators (PAGs), catalysts, and combinations thereof.

11. The method of claim 10 , wherein said treating comprises baking the initial layer at a temperature and for a period of time suitable for covalently linking the polymer of claim 1 to the substrate.

12. The method of claim 9 , wherein each block of the block copolymer is capable of wetting the orientation control layer.

13. The method of claim 9 , wherein the block copolymer is capable of forming a domain pattern having a bulk periodicity (Lo) in the range of about 4 nm to about 40 nm.

14. The method of claim 9 , wherein carbonate repeat units of the polymer of claim 1 have the same chemical structures as carbonate repeat units of the polycarbonate block of the block copolymer.

15. The method of claim 9 , wherein carbonate repeat units of the polymer of claim 1 have chemical structures different than those of the carbonate repeat units of the polycarbonate block of the block copolymer.

16. The method of claim 9 , wherein the block copolymer comprises:
i) a first block comprising a repeat unit of formula (B-1):

wherein a) R w is a monovalent radical selected from the group consisting of H, methyl, ethyl, and trifluoromethyl (*—CF 3 ) and b) R d is a monovalent radical comprising an aromatic ring, and
ii) a second block comprising a repeat unit of formula (B-2):

wherein a) R e is an independent monovalent radical selected from the group consisting of hydrogen, methyl, and ethyl and b) J″ is an independent monovalent radical selected from the group consisting of hydrogen and monovalent radicals comprising 1 to 10 carbons,
and wherein the first block and the second block of the block copolymer are covalently linked.

17. The method of claim 16 , wherein R w of formula (B-1) is hydrogen, and R d is phenyl.

18. The method of claim 16 , wherein J″ and R e are hydrogen of formula (B-2).

19. An article (modified substrate), comprising:
a substrate; and
an orientation control layer disposed on a surface of the substrate, the orientation control layer comprising a derivative of the polymer of claim 1 which is covalently linked to the surface of the substrate, wherein the derivative comprises:
i) a divalent first repeat unit of formula (A-1):

wherein
R x is a monovalent radica

Assignees

• IBM

Inventors

• Cheng Joy
• Chunder Anindarupa
• Tjio Melia
• Vora Ankit

Classifications

• C08F212/22

  Oxygen · CPC title

• C08F212/24

  Phenols or alcohols · CPC title

• C08F2438/01

  Atom Transfer Radical Polymerization [ATRP] or reverse ATRP · CPC title

• C09D125/14 Primary

  with unsaturated esters · CPC title

• C08F8/14

  Esterification · CPC title