Lift-off patterning processes employing energetically-stimulated local removal of solid-condensed-gas layers
The invention provides a method for forming a patterned material layer on a structure, by condensing a vapor to a solid condensate layer on a surface of the structure and then localized removal of selected regions of the condensate layer by directing an ion beam at the selected regions, exposing the structure at the selected regions. A material layer is then deposited on top of the solid condensate layer and the exposed structure at the selected regions. Then the solid condensate layer and regions of the material layer that were deposited on the solid condensate layer are removed, leaving a patterned material layer on the structure.
1. A method for forming a nano-patterned material layer on a structure, comprising:
condensing a vapor to an amorphous solid water condensate layer on a surface of the structure;
localized removal of at least one selected nanometric region of the condensate layer by directing a focused ion beam at the selected region, exposing the structure at the selected region;
depositing a material layer on top of the solid condensate layer and on the exposed structure at the selected region; and
removing the solid condensate layer and regions of the material layer that were deposited on top of the solid condensate layer, leaving a patterned material layer on the structure.
2. The method of claim 1 wherein the ion beam comprises a substantially inert ion beam species.
3. The method of claim 1 wherein the ion beam comprises a Ga + ion beam.
4. The method of claim 1 wherein the focused ion beam comprises a focused ion beam having a diameter of about 10 nm.
5. The method of claim 1 wherein the vapor that is condensed to a solid condensate layer comprises water vapor.
6. The method of claim 1 wherein the material layer is deposited by a vapor deposition process.
7. The method of claim 1 further comprising, after depositing the material layer, providing access apertures in the material layer to allow removal of the solid condensate layer.
8. The method of claim 1 wherein the material layer comprises an electrically conducting material.
9. The method of claim 8 wherein the material layer comprises chromium.
10. The method of claim 8 wherein the material layer comprises aluminum.
11. The method of claim 8 wherein the material layer comprises silver.
12. The method of claim 8 wherein the material layer comprises palladium.
13. The method of claim 1 wherein the structure comprises a silicon substrate.
14. The method of claim 1 further comprising controlling temperature and pressure conditions local to the structure during localized removal of the solid condensate layer and deposition of the material layer to substantially maintain stability of the solid condensate layer.
15. The method of claim 1 wherein removal of the solid condensate layer and regions of the material layer that were deposited on the solid condensate layer comprises conversion of the solid condensate layer to a vapor.
16. The method of claim 1 wherein removal of the solid condensate layer and regions of the material layer that were deposited on the solid condensate layer comprises a process of lift-off of the material layer regions as the solid condensate layer is removed.