Claims
- 1. A method for forming a thin film aerogel on a semiconductor substrate, the method comprising the steps of:a) providing a semiconductor substrate comprising a microelectronic circuit; b) depositing an aerogel precursor sol upon said substrate; wherein said aerogel precursor sol comprises a metal-based aerogel precursor reactant, wherein said reactant is a compound containing metal atoms, an alcohol, and a first solvent comprising a first polyol; wherein, the molar ratio of said first solvent molecules to the metal atoms in said reactant is at least 1 first solvent molecule per 16 metal atoms; c) allowing said deposited sol to create a gel, wherein said gel comprises a porous solid and a pore fluid; and d) forming a dry aerogel by removing said pore fluid in a drying atmosphere, wherein the pressure of said drying atmosphere during said forming step is less than the critical pressure of said pore fluid, and the temperature of said substrate during said forming step is above the freezing temperature of said pore fluid.
- 2. A method for forming a thin film nanoporous dielectric on a semiconductor substrate, the method comprising the steps of:a) providing a semiconductor substrate; b) depositing an aerogel precursor sol upon said substrate; wherein said aerogel precursor sol comprises a metal-based aerogel precursor reactant, wherein said reactant is a compound containing metal atoms, an alcohol, and a first solvent comprising a polyol; wherein, the molar ratio of said first solvent molecules to the metal atoms in said reactant is at least 1 first solvent molecule per 16 metal atoms; c) allowing said deposited sol to create a gel, wherein said gel comprises a porous solid and a pore fluid; and d) forming a dry, nanoporous dielectric by removing said pore fluid in a drying atmosphere, wherein the pressure of said drying atmosphere during said forming step is less than the critical pressure of said pore fluid, and the temperature of said substrate during said forming step is above the freezing temperature of said pore fluid.
- 3. A method for forming a thin film nanoporous dielectric on a semiconductor substrate, the method comprising the steps of:a) providing a semiconductor substrate; b) depositing an aerogel precursor sol upon said substrate; wherein said aerogel precursor sol comprises an aerogel precursor reactant selected from the group consisting of metal alkoxides, at least partially hydrolyzed metal alkoxides, and combinations thereof, wherein said metal alkoxide contains metal atoms, and a first solvent comprising a polyol; wherein, the molar ratio of said first solvent molecules to the metal atoms in said reactant is at least 1 first solvent molecule per 16 metal atoms; c) allowing said deposited sol to create a gel, wherein said gel comprises a porous solid and a pore fluid; and d) forming a dry, nanoporous dielectric by removing said pore fluid in a drying atmosphere without substantially collapsing said porous solid, wherein the pressure of said drying atmosphere during said forming step is less than the critical pressure of said pore fluid, and the temperature of said substrate during said forming step is above the freezing temperature of said pore fluid.
- 4. The method of claim 3, wherein:the molar ratio of said first solvent molecules to the metal atoms in said reactant is no greater than 12:1.
- 5. The method of claim 3, wherein:the molar ratio of said first solvent molecules to the metal atoms in said reactant is between 1:2 and 12:1.
- 6. The method of claim 3, wherein:the molar ratio of said first solvent molecules to the metal atoms in said reactant is between 2.5:1 and 12:1.
- 7. The method of claim 3, wherein:said nanoporous dielectric has a porosity greater than 60% and an average pore diameter less than 100 nm.
- 8. The method of claim 3, wherein:said method does not comprise the step of adding a surface modification agent before said forming step.
- 9. The method of claim 3, wherein:said nanoporous dielectric has a porosity greater than 60% and an average pore diameter less than 100 nm; wherein, said method does not comprise the step of adding a surface modification agent before said forming step.
- 10. The method of claim 3, further comprising the step of:aging said gel before said forming step.
- 11. The method of claim 10, wherein:at least part of said aging step is performed in a substantially closed container.
- 12. The method of claim 10, wherein:the temperature of said gel during said aging is greater than 30 degrees C.
- 13. The method of claim 10, wherein:the temperature of said gel during said aging is greater than 80 degrees C.
- 14. The method of claim 10, wherein:the temperature of said gel during said aging is greater than 130 degrees C.
- 15. The method of claim 1, wherein the alcohol is ethanol.
- 16. The method of claim 2, wherein the alcohol is ethanol.
- 17. The method of claim 3, wherein the aerogel precursor sol also comprises ethanol.
Parent Case Info
This application claims benefit of provisional application Ser. No. 60/006,852 filed Nov. 16, 1995, provisional Ser. No. 60/006,853 filed Nov. 16, 1995, provisional Ser. No. 60/012,764 filed Mar. 4, 1996, provisional Ser. No. 60/012,800 filed Mar. 4, 1996, provisional Ser. No. 60/014,005 filed Mar. 25, 1996, and a continuation of Ser. No. 08/748,926 filed Nov. 14, 1996 now U.S. Pat. No. 5,807,607.
US Referenced Citations (26)
Foreign Referenced Citations (3)
Number |
Date |
Country |
382310 |
Aug 1990 |
EP |
454239 |
Oct 1991 |
EP |
WO 9203378 |
Mar 1992 |
WO |
Non-Patent Literature Citations (6)
Entry |
Einarsrud et al, Chem. Process. Adv. Mater., pp 355-61, 1992. |
Haereid, Norges Tekniske Hogskole, vol. 69, pp 7-218, Jan. 1993. |
Siv Hæreid, Preparation and Characterization of Transparent Monolithic Silica Xerogels with Low Density, Jan. 1993, Norges Tekniske Hogskole Universiteteti I Trondheim. |
V.S. Klimenko, L.A. Kulik, and V.V. Vashchinskaya, Dependence of the Composition and Structure of Silicic Acid Xerogels on the Nature of the Solvent, 1986, Ukrainskii Khimicheskii Zhurnal, vol. 52, No. 12, pp. 1247-1251. |
D. Basmadjian, G. N. Fulford, B.I. Parsons, and D.S. Montgomery, The Control of the Pore, Volume and Pore Size Distribution in Alumina and Silica Gels by the Addition of Water Soluble Organic Polymers Dec. 1962, Journal of Catalysis, vol. 1, No. 6, pp. 547-563. |
H. Yokogawa, M. Yokoyama, Hydrophobic Silica Aerogels, Journal of Non-Crystalline Solids 186 (1995) 23-29. |
Provisional Applications (5)
|
Number |
Date |
Country |
|
60/006852 |
Nov 1995 |
US |
|
60/006853 |
Nov 1995 |
US |
|
60/012764 |
Mar 1996 |
US |
|
60/012800 |
Mar 1996 |
US |
|
60/014005 |
Mar 1996 |
US |
Continuations (1)
|
Number |
Date |
Country |
Parent |
08/748926 |
Nov 1996 |
US |
Child |
09/115854 |
|
US |