Thermal anneal of block copolymer films with top interface constrained to wet both blocks with equal preference

• US 8,633,112 B2
• Filed: 05/11/2012
• Issued: 01/21/2014
• Est. Priority Date: 03/21/2008
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Millward, Dan B., Quick, Timothy
• Primary Examiner(s): Deo, Duy
• Assistant Examiner(s): GATES, BRADFORD M
• Application Number:
  US13/469,697
• Publication Number:
  US 20120223053A1
• Time in Patent Office: 620 Days
• Field of Search: None
• US Class Current: 438/700
• CPC Class Codes: B81C 1/00031 Regular or irregular arrays of nanoscale structures, e.g. etch mask layer photomechanical, e.g. photolithographic, production of textured or patterned surfaces G03F7/00; lithographic processes for making patterned surfaces using printing and stamping G03F7/0002
• CPC Class Codes: B81C 2201/013 Etching
• CPC Class Codes: B81C 2201/0149 Forming nanoscale microstructures using auto-arranging or self-assembling material
• CPC Class Codes: B81C 2201/0198 for making a masking layer
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C08F 299/02 from unsaturated polycondensates
• CPC Class Codes: C08F 299/0492 the unsaturation being in acrylic or methacrylic groups
• CPC Class Codes: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: H01L 21/0337 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 21/0338 Process specially adapted to improve the resolution of the mask
• CPC Class Codes: H01L 21/31133 by chemical means
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics
• CPC Class Codes: H01L 21/76816 Aspects relating to the layout of the pattern or to the size of vias or trenches layout of the interconnections per se H01L23/528; CAD of ICs G06F30/00
• CPC Class Codes: H01L 21/76828 thermal treatment
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material

Abstract

Methods for fabricating sub-lithographic, nanoscale microstructures utilizing self-assembling block copolymers, and films and devices formed from these methods are provided.

Claims

1. A method of etching a substrate, comprising:

thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material to cause polymer blocks of the block copolymer material to phase separate and self-assemble within a trench in a material layer overlying a substrate, the trench having a neutral wetting floor and preferentially wetting sidewalls and ends;

selectively crosslinking a first block of the self-assembled block copolymer material;

selectively removing a second block of the self-assembled block copolymer material to form openings extending through the self-assembled block copolymer material; and

removing at least a portion of the substrate through the openings.

2. The method of claim 1, wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material comprises:

heating a first section of the block copolymer material to cause the first section to phase separate and self-assemble, and then subsequently heating remaining sections of the block copolymer material to cause the remaining sections to phase separate and self-assemble.

3. The method of claim 1, wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material comprises annealing the block copolymer material in a solvent vapor that is non-preferential to any polymer block.

4. The method of claim 1, wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material comprises annealing the block copolymer material in a partly-saturated concentration of the organic solvent.

5. The method of claim 1, wherein the block copolymer material comprises a cylindrical-phase block copolymer.

6. The method of claim 1, wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material comprises self-assembling the block copolymer material into cylinders of the second block within a matrix of the first block of the block copolymer material, the cylinders oriented perpendicular to and extending from a floor of the trench to an interface of the block copolymer material and the vapor of the organic solvent.

7. The method of claim 1, wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material comprises:

zone heating the block copolymer material in the vapor of the organic solvent to cause polymer blocks of the block copolymer material to phase separate and self-assemble within a trench.

8. The method of claim 7, wherein zone heating the block copolymer material comprises heating a first section of the block copolymer material within the trench to cause the block copolymer material to phase separate and self-assemble, and then heating subsequent sections of the block copolymer material within the trench.

9. The method of claim 1, wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material comprises:

zone heating a first section and then subsequent sections of the block copolymer material in the vapor of the organic solvent to cause the block copolymer material phase to separate and self-assemble in the first section and then in the subsequent sections.

10. The method of claim 1, further comprising, prior to thermally annealing the block copolymer material in the vapor of the organic solvent and at the temperature above the glass transition temperature (T_g) of the block copolymer material, heating the block copolymer material and the substrate above a boiling point of the organic solvent to minimize swelling of the block copolymer material.

11. The method of claim 1, wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material comprises maintaining a concentration of the organic solvent in the air at a vapor interface with the block copolymer material at or under saturation.

12. The method of claim 1, wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material comprises globally heating the block copolymer material.

13. The method of claim 1, wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material comprises exposing the substrate to a cold-to-hot temperature gradient to anneal the block copolymer material.

14. The method of claim 1, wherein thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material comprises heating the block copolymer material above an order-disorder temperature of the block copolymer material, and cooling the heated block copolymer material to below the order-disorder temperature but above a glass transition temperature of the block copolymer material.

15. A method of etching a substrate, comprising:

thermally annealing a block copolymer material in contact with a non-preferentially wetting solid material to cause polymer blocks of the block copolymer material to phase separate and self-assemble within a trench in a material overlying a substrate;

removing the non-preferentially wetting solid material to expose the self-assembled block copolymer material;

selectively crosslinking a first block of the self-assembled block copolymer material;

selectively removing a second block of the self-assembled block copolymer material to form openings extending through the self-assembled block copolymer material; and

removing at least a portion of the substrate through the openings.

16. The method of claim 15, wherein thermally annealing a block copolymer material in contact with a non-preferentially wetting solid material comprises:

zone heating a first section of the block copolymer material to cause the first section to phase separate and self-assemble, and then subsequently heating remaining sections of the block copolymer material to cause the remaining sections to phase separate and self-assemble.

17. The method of claim 15, wherein the non-preferentially wetting solid material comprises an elastomeric material.

18. The method of claim 17, wherein the elastomeric material is selected from the group consisting of poly(dimethylsiloxane) and poly(urethane).

19. The method of claim 15, further comprising applying a solvent to the non-preferentially wetting solid material to enhance removal.

20. The method of claim 15, wherein the block copolymer material comprises poly(styrene)-b-poly(vinylpyridine) (PS-b-PVP), poly(styrene)-b-poly(methyl methacrylate) (PS-b-PMMA), poly(styrene)-b-polyacrylate, poly(styrene)-b-poly(methacrylate), poly(styrene)-b-poly(lactide) (PS-b-PLA), poly(styrene)-b-poly(tert-butyl acrylate) (PS-b-PtBA), poly(styrene)-b-poly(ethylene-co-butylene (PS-b-(PS-co-PB)), poly(styrene)-b-poly(ethylene oxide) (PS-b-PEO), poly(isoprene)-b-poly(ethyleneoxide) (PI-b-PEO), poly(isoprene)-b-poly(methyl methacrylate) (PI-b-PMMA), poly(butadiene)-b-poly(ethyleneoxide) (PBD-b-PEO), poly(styrene)-b-PEO block copolymer having a cleavable junction between PS and PEO blocks, poly(styrene)-b-poly(methyl methacrylate) doped with PEO-coated gold nanoparticles, poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer having a cleavable junction, poly(styrene-b-methyl methacrylate-b-ethylene oxide) (PS-b-PMMA-b-PEO), poly(styrene-b-methyl methacrylate-b-styrene) (PS-PMMA-PS), poly(methyl methacrylate-b-styrene-b-methyl methacrylate) (PMMA-PS-PMMA), poly(styrene-b-poly(isoprene)-b-styrene) (PS-b-PI-b-PS), or combinations thereof.

21. The method of claim 15, wherein thermally annealing a block copolymer material in contact with a non-preferentially wetting solid material comprises self-assembling the block copolymer material into at least one row of perpendicular-oriented cylinders of the second block within a matrix of the first block of the block copolymer material, with the cylinders registered and parallel to sidewalls of the trench.

22. The method of claim 15, wherein thermally annealing a block copolymer material in contact with a non-preferentially wetting solid material comprises self-assembling the block copolymer material into cylinder domains of the second block within a matrix of the first block of the block copolymer material, and wherein selectively removing a second block of the self-assembled block copolymer material comprises removing the cylinder domains of the second block to form openings in the matrix of the self-assembled block copolymer material.

23. The method of claim 22, further comprising, after removing at least a portion of the substrate through the openings, removing the matrix of the self-assembled block copolymer material, and then filling the openings with a metal, a metal alloy, or a metal-insulator-metal stack.

24. The method of claim 15, wherein removing the non-preferentially wetting solid material to expose the self-assembled block copolymer material comprises etching the non-preferentially wetting solid material with a dilute fluoride solution.

25. A method of etching a substrate, comprising:

thermally annealing a block copolymer material in a vapor of an organic solvent and at a temperature above the glass transition temperature (T_g) of the block copolymer material to self-assemble the block copolymer material into cylinder domains of a second block within a matrix of a first block of the block copolymer material within a trench in a material layer overlying a substrate, the trench having a neutral wetting floor and preferentially wetting sidewalls and ends;

selectively removing the cylinder domains of the second block to form openings exposing the substrate at the trench floor; and

removing at least a portion of the substrate through the openings.