Methods of etching silicon-containing films on silicon substrates
A method for selectively etching a silicon-containing film on a silicon substrate is disclosed. The method includes depositing a silicon-containing film on the silicon substrate. The method further includes baking the silicon-containing film to create a densified silicon-containing film, wherein the densified film has a first thickness. The method also includes exposing the silicon substrate to an aqueous solution comprising NH 4 F and HF in a ratio of between about 6:1 and about 100:1, at a temperature of between about 20° C. and about 50° C., and for a time period of between about 30 seconds and about 5 minutes; wherein between about 55% and about 95% of the densified silicon-containing film is removed.
1. A method for selectively etching a densified film on a silicon substrate comprising:
depositing a silicon-containing film on a silicon substrate with a deposition tool;
baking the silicon-containing film at a baking temperature and for a baking time period to create a densified film, wherein the densified film has a first thickness;
exposing the silicon substrate to an aqueous solution comprising NH 4 F and HF in a ratio of between about 6:1 and about 100:1, at a temperature of between about 20° C. and about 50° C., and for a time period of between about 30 seconds and about 5 minutes;
wherein between about 55% and about 95% of the densified film is removed and wherein the baking temperature is between about 100° C. and about 550° C.
2. The method of claim 1 , wherein the NH 4 F and HF ratio is between about 25:1 and about 100:1, at a temperature of between about 20° C. and about 40° C., and for a time period of between about 30 seconds and about 3 minutes.
3. The method of claim 1 , wherein the NH 4 F and HF ratio is about 25:1 at a temperature of between about 25° C. and about 35° C., and for a time period of between about 30 seconds and about 3 minutes.
4. The method of claim 1 , further including the step of texturing the silicon substrate with a texturing process.
5. The method of claim 4 , wherein the texturing process is one of acidic texturing and alkaline texturing.
6. The method of claim 1 , wherein the substrate is one of a random pyramid textured substrate and a smooth textured substrate.
7. The method of claim 1 , wherein the baking time period is between about 30 seconds and about 12 minutes.
8. The method of claim 1 , wherein the densified film has a film thickness of between about 30 nm to about 30 μm.
9. The method of claim 1 , wherein the densified film contains more than about 50% silicon by weight.
10. The method of claim 1 , wherein the densified film comprises a set of silicon-containing nanoparticles.
11. The method of claim 10 , wherein an average diameter of each of the set of silicon-containing nanoparticles is between about 2 nm and about 30 nm.
12. The method of claim 1 , wherein the deposition tool is one of an ink-jet deposition tool, a screen-print deposition tool, and a spray-coating deposition tool.
13. A method for selectively etching a densified film on a silicon substrate comprising:
depositing a silicon-containing film on a silicon substrate with a deposition tool;
baking the silicon-containing film at a baking temperature and for a baking time period to create a densified film, wherein the densified film has a first thickness;
exposing the silicon substrate to an aqueous solution comprising NH 4 F and HF in a ratio of between about 6:1 and about 100:1, at a temperature of between about 20° C. and about 50° C., and for a time period of between about 30 seconds and about 5 minutes;
wherein between about 55% and about 95% of the densified film is removed and wherein the baking time period is between about 30 seconds and about 12 minutes.
14. The method of claim 13 , wherein the NH 4 F and HF ratio is between about 25:1 and about 100:1, at a temperature of between about 20° C. and about 40° C., and for a time period of between about 30 seconds and about 3 minutes.
15. The method of claim 13 , wherein the NH 4 F and HF ratio is about 25:1 at a temperature of between about 25° C. and about 35° C., and for a time period of between about 30 seconds and about 3 minutes.
16. The method of claim 13 , further including the step of texturing the silicon substrate with a texturing process.
17. The method of claim 16 , wherein the texturing process is one of acidic texturing and alkaline texturing.
18. The method of claim 13 , wherein the substrate is one of a random pyramid textured substrate and a smooth textured substrate.
19. The method of claim 13 , wherein the densified film has a film thickness of between about 30 nm to about 30 μm.
20. The method of claim 13 , wherein the densified film contains more than about 50% silicon by weight.
21. The method of claim 13 , wherein the densified film comprises a set of silicon-containing nanoparticles.
22. The method of claim 21 , wherein an average diameter of each of the set of silicon-containing nanoparticles is between about 2 nm and about 30 nm.
23. The method of claim 13 , wherein the deposition tool is one of an ink jet deposition tool, a screen-print deposition tool, and a spray-coating deposition tool.
24. A method for selectively etching a densified film on a silicon substrate comprising:
depositing a silicon-containing film on a silicon substrate with a deposition tool;
baking the silicon-containing film at a baking temperature and for a baking time period to create a densified film, wherein the densified film has a first thickness;
exposing the silicon substrate to an aqueous solution comprising NH 4 F and HF in a ratio of between about 6:1 and about 100:1, at a temperature of between about 20° C. and about 50° C., and for a time period of between about 30 seconds and about 5 minutes;
wherein between about 55% and about 95% of the densified film is removed and wherein the densified film comprises a set of silicon-containing nanoparticles.
25. The method of claim 24 , wherein the NH 4 F and HF ratio is between about 25:1 and about 100:1, at a temperature of between about 20° C. and about 40° C., and for a time period of between about 30 seconds and about 3 minutes.
26. The method of claim 24 , wherein the NH 4 F and HF ratio is about 25:1 at a temperature of between about 25° C. and about 35° C., and for a time period of between about 30 seconds and about 3 minutes.
27. The method of claim 24 , further including the step of texturing the silicon substrate with a texturing process.
28. The method of claim 27 , wherein the texturing process is one of acidic texturing and alkaline texturing.
29. The method of claim 24 , wherein the substrate is one of a random pyramid textured substrate and a smooth textured substrate.
30. The method of claim 24 , wherein the densified film has a film thickness of between about 30 nm to about 30 μm.
31. The method of claim 24 , wherein the densified film contains more than about 50% silicon by weight.
32. The method of claim 24 , wherein an average diameter of each of the set of silicon-containing nanoparticles is between about 2 nm and about 30 nm.
33. The method of claim 24 , wherein the deposition tool is one of an ink-jet deposition tool, a screen-print deposition tool, and a spray-coating deposition tool.