Method for filling of nanoscale holes and trenches and for planarizing of a wafer surface
A processing method for use in the fabrication of fabrication of nanoscale electronic, optical, magnetic, biological, and fluidic devices and structures, for filling nanoscale holes and trenches, for planarizing a wafer surface, or for achieving both filling and planarizing of a wafer surface simultaneously. The method has the initial step of depositing a layer of a meltable material on a wafer surface. The material is then pressed using a transparent mold while shining a light pulse through the transparent mold to melt the deposited layer of meltable material. A flow of the molten layer material fills the holes and trenches, and conforms to surface features on the transparent mold. The transparent mold is subsequently removed.
1. A method of making a product having at least one nanoscale feature comprising the steps of:
providing a substrate of a first material having a first surface including at least one recessed region;
coating at least the portion of the first surface comprising the recessed region with a thin layer of a meltable second material;
providing a mold having a molding surface;
pressing together the mold and the substrate with the molding surface pressing the layer of meltable second material; and
while the molding surface is pressing the layer of meltable second material, exposing the layer of meltable second material to radiation to melt the layer, thereby increasing the penetration of the meltable second material into the recessed region of the substrate.
2. The method of claim 1 wherein the molding surface is substantially planar; and wherein the pressing and exposing planarize the thin layer.
3. The method of claim 1 wherein the substrate comprises an insulating region, the at least one recessed region is located in the insulating region and the meltable second material comprises a conductive material.
4. The method of claim 1 wherein the substrate comprises a semiconductive material.
5. The method of claim 1 wherein the radiation comprises laser radiation.
6. The method of claim 1 wherein the mold is substantially transparent to the radiation.
7. The method of claim 6 wherein the radiation comprises the laser radiation.
8. The method of claim 1 wherein the substrate is substantially transparent to the radiation.
9. The method of claim 8 wherein the radiation comprises laser radiation.
10. The method of claim 1 wherein the radiation comprises pulsed laser radiation.
11. The method of claim 1 wherein the radiation comprises ultraviolet radiation.
12. The method of claim 1 wherein the meltable second material comprises semiconductor material.
13. The method of claim 12 wherein the semiconductor material comprises silicon.
14. The method of claim 1 wherein the meltable second material comprises metal.
15. The method of claim 14 wherein the metal comprises copper.
16. The method of claim 1 wherein the molding surface is optically smooth.
17. The method of claim 1 wherein the at least one recessed region comprises a periodic array of recessed regions.
18. The method of claim 1 wherein the coating comprises physical vapor deposition.
19. The method of claim 18 wherein the physical vapor deposition comprises electron beam evaporation.
20. The method of claim 1 wherein the recessed feature has an aspect ratio of at least 5 to 1.
21. The method of claim 1 wherein the mold comprises silicon.
22. The method of claim wherein the exposing to radiation comprises exposing to laser radiation in a substantial vacuum.
23. The method of claim 1 wherein the exposure to radiation comprises exposure to laser radiation of short duration to reduce thermal burden.
24. The method of claim 1 wherein the at least one recessed region comprises a trench with a minimum width of less than 200 nanometers.
25. The method of claim 1 wherein the at least one recessed region comprises a hole with a minimum effective diameter of less than 200 nanometers.
26. The method of claim 1 wherein the at least one recessed region comprises a plurality recessed regions each having at lest one lateral feature with a minimum dimension of less than 200 nanometers.
27. The method of claim 26 wherein the plurality of recessed regions comprises a plurality of substantially parallel trenches.
28. The method of claim 26 wherein the plurality of recessed regions comprises a plurality of spaced apart holes.