Functionalized fullerenes for nanolithography applications
View Patent ↗A method for electron beam nanolithography without the need for development step involves depositing a film of a resist comprising functionalized fullerenes on a substrate, and writing features by exposure to an electron beam with an accelerating voltage and dose rate sufficient to promote heating or thermal degradation of the functionalized fullerene in the irradiated volume such that a pattern is generated without a subsequent development step or with an aqueous developer. Lithographic features of about 1 nm or greater can be formed.
1. A development free method for electron beam lithography comprising the steps of:
depositing a resist comprising functionalized fullerenes on a substrate; and
projecting an electron beam upon said resist with an accelerating voltage and dose rate that initiates thermal degradation of said resist, wherein a pattern of voids is formed in said resist.
2. The method according to claim 1 , wherein said step of depositing comprises:
combining said resist with a solvent to form a resist solution; and
spin-coating said resist solution on said substrate.
3. The method of claim 1 , wherein said functionalized fullerenes comprise:
fullerenes (C x where x is 20 to 1500) with side groups attached to said fullerene by covalent bonds, ionic bonds, or Dewar coordination, Kubas interactions, or any combination thereof;
substituted fullerenes;
endohedral fullerenes; or
any combinations thereof.
4. The method of claim 3 , wherein said side groups comprise OH, Br, H, Gd, Ti, or C(COOH) 2 .
5. The method according to claim 1 , wherein said resist comprises at least one functionalized fullerene and at least one organic polymer.
6. The method according to claim 5 , wherein said polymer comprises poly(methyl methacrylate), poly(2,2,2-trifluoroethyl-chloroacrylate), poly(butene-1-sulfone), a copolymer of chloromethacrylate and methylstyrene, polyvinyl alcohol, carboxy methyl cellulose, or carbopol.
7. The method according to claim 1 , wherein said resist is water soluble.
8. The method according to claim 1 , wherein said accelerating voltage is 1 to 30 kV and said dose rate is at least 10 μC cm −2 .
9. The method according to claim 1 , further comprising the step of doping said substrate exposed by said voids in said resist.
10. The method according to claim 1 , further comprising the step of etching said substrate exposed by said voids in said resist.
11. A water-developable method for electron beam lithography comprising the steps of:
depositing a resist comprising functionalized fullerenes on a substrate;
projecting an electron beam upon said resist having an accelerating voltage and dose rate wherein thermal degradation of said resist occurs; and
developing the resist with water wherein a pattern of voids is formed in said resist.
12. The method according to claim 11 , wherein said step of depositing comprises:
combining said resist with a solvent to form a resist solution; and
spin-coating said resist solution on said substrate.
13. The method of claim 11 , wherein said functionalized fullerenes comprise:
fullerenes (C x where x is 20 to 1500) with side groups attached to said fullerene by covalent bonds, ionic bonds, or Dewar coordination, Kubas interactions, or any combination thereof;
substituted fullerenes;
endohedral fullerenes; or
any combination thereof.
14. The method of claim 13 , wherein said side groups comprise OH, Br, H, Gd, Ti, or C(COOH) 2 .
15. The method according to claim 11 , wherein said resist comprises at least one functionalized fullerene and at least one organic polymer.
16. The method according to claim 15 , wherein said polymer comprises poly(methyl methacrylate), poly (vinyl alcohol), poly (acrylic acid), poly (vinyl pyrrolidone), poly (ethylene glycol), poly (lactic co-glycolic acid), poly (ethylene oxide), carboxy methyl cellulose, or carbopol.
17. The method according to claim 11 , wherein said resist is water soluble.
18. The method according to claim 11 , wherein said accelerating voltage is 1 to 30 kV and said dose rate is at least 10 μC cm −2 .
19. The method according to claim 11 , further comprising the step of doping said substrate exposed by said voids.
20. The method according to claim 11 , further comprising the step of etching said substrate exposed by said voids.