Photocatalytic reactions in nano-imprint lithography processes
View Patent ↗An imprint lithography template having a photoactive coating adhered to a surface of the template. Irradiation of the photoactive coating promotes cleaning of the template by decomposition of organic material proximate the template (e.g., organic material adsorbed on the template). An imprint lithography system may be configured such that template cleaning is achieved during formation of a patterned layer on an imprint lithography substrate. Cleaning of the template during an imprint lithography process reduces down-time that may be associated with template maintenance.
1. A method of forming an anti-wetting layer on an imprint lithography template comprising:
providing an imprint template having an etched-back surface having hydroxyl groups;
applying an anti-wetting film to the etched-back surface, the anti-wetting film including a silane, a photoinitiator, and a solvent;
evaporating the solvent from the anti-wetting film; and
exposing the anti-wetting film to radiation, whereby the photoinitiator upon exposure to the radiation generates a catalyst that catalyzes:
(i) condensation reactions between the silane and the hydroxyl groups of the etched-back surface to yield silane components coupled to the etched-back surface, and
(ii) condensation reactions between the silane components coupled to the etched-back surface to form Si—O—Si bonds between the silane components,
thereby forming an anti-wetting layer comprising silane components coupled to each other and to the etched-back surface of the imprint template.
2. The method of claim 1 wherein the silane is a fluorinated silane.
3. The method of claim 1 wherein the silane is selected from the group consisting of alkoxysilanes and chlorosilanes.
4. The method of claim 1 wherein the radiation is ultraviolet radiation.
5. The method of claim 1 wherein the generated catalyst is a superacid.
6. The method of claim 5 wherein the superacid is fluoroantimonic acid (HSbF 6 ).
7. The method of claim 1 wherein the silane is a monofunctional silane having a single silicon atom, a difunctional silane having two silicon atoms, or a combination thereof.
8. The method of claim 7 wherein the silane is a difunctional silane, and both silicon atoms of the difunctional silane are coupled to the etched back surface.
9. The method of claim 8 wherein the difunctional silane is fluorinated, and the fluorinated portion of the difunctional silane extends between the two silicon atoms coupled to the etched back surface.
10. The method of claim 7 wherein the silane comprises (tridecafluoro-1,1,2,2-tetrahydrooctyl) trichlorosilane (FOTS).
11. The method of claim 1 wherein the anti-wetting layer comprises a Si—O—Si network among the silane components coupled to the etched back surface.
12. The method of claim 1 wherein the photoinitiator is a cationic photoinitiator.
13. The method of claim 1 wherein the imprint template comprises silicon.
14. The method of claim 13 wherein the imprint template is formed from a material selected from the group consisting of fused-silica, quartz, silicon, siloxane polymers, and borosilicates.
15. The method of claim 13 wherein the hydroxyl groups of the etched-back surface of the imprint template are bonded to the silicon in the template.
16. The method of claim 1 wherein the solvent is a fluorinated solvent.
17. The method of claim 1 wherein the total content of the silane and the photoinitiator in the anti-wetting film is from about 0.001 wt % to about 5 wt %.
18. The method of claim 1 wherein the total content of the silane and the photoinitiator in the anti-wetting film is from about 0.01 wt % to about 1 wt %.
19. The method of claim 1 wherein the catalyst catalyzes hydrolysis of the silane.
20. The method of claim 19 wherein the catalyst reduces the dependence of the silane hydrolysis on environmental humidity.