Aerosol misted deposition of low dielectric organosilicate films
View Patent ↗This invention relates to an improvement in a deposition process for producing low dielectric films having a dielectric constant of 3, preferably <2.7 and lower. The process comprises the steps: (a) forming a liquid precursor solution comprised of an organosilicon source containing both Si—O and Si—C bonds and solvent; (b) generating a liquid mist of said liquid precursor solution, said mist existing as precursor solution droplets having a number average droplet diameter size of less than 0.5 μm; (c) preferably electrically charging the liquid mist of said liquid precursor solution droplets; (d) depositing liquid mist of said liquid precursor solution droplets onto a substrate; and, (e) converting the thus deposited liquid mist of said liquid precursor solution droplets to a solid, low dielectric film.
1. A liquid source misted deposition process capable of producing a solid, low dielectric film on a substrate which comprises the steps:
(a) providing a liquid mist of a liquid precursor solution comprised of a low dielectric organosilane source containing both Si—O and Si—C bonds and a solvent, said liquid mist existing as precursor solution droplets having a number average droplet diameter size of less than 0.5 μm and suited for deposition in said liquid source misted deposition process;
(b) electrically charging said precursor solution droplets to form a liquid mist of electrically charged precursor solution droplets;
(c) depositing said electrically charged precursor solution droplets onto an electrically charged substrate of opposite bias and forming a film of precursor solution droplets on said substrate; and,
(d) converting said film of precursor solution droplets to a solid low dielectric film on said substrate for use in the microelectronics industry as an insulating component.
2. The process of claim 1 wherein a soluble silicate network forming precursor is included in the liquid precursor solution and said soluble silicate network forming precursor has four Si—OR bonds and the OR group is a reactive alkoxide, hydroxide, or acetate.
3. The process of claim 1 wherein the liquid precursor solution has a molar ratio of said organosilane to soluble silicate network forming precursor ranging from 0.01 to 20:1.
4. The process of claim 3 wherein the organosilane is selected from the group consisting of methyltriethoxysilane, methyltriacetoxysilane, phenyltrimethoxysilane, ethyltriethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, methyltrichlorosilane, methyltrihydroxysilane, octamethyltetrasiloxane, methylpentamethoxydisiloxane, diethoxymethylsilane and tetramethylcyclosiloxane.
5. The process of claim 3 wherein the soluble silicate network forming precursors are selected from the group consisting of tetraethylorthosilicate, tetrabutoxysilane, tetraacetoxysilane, and dimethoxydiacetoxysilane.
6. The process of claim 1 wherein the film is formed at a deposition rate of 30 to 50 angstroms/second.