Method of decreasing the K value in SIOC layer deposited by chemical vapor deposition

A method for processing a substrate, comprising:

• reacting a gas mixture comprising an organosilicon compound selected from the group consisting of methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, dimethylsilanediol, ethylsilane, phenylsilane, diphenylsilane, diphenylsilanediol, methylphenylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilanopropane, 1,3,5-trisilano-2,4,6-trimethylene, dimethyldimethoxysilane, diethyldiethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, 1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)propane, 1,3,5,7-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3,5-trisilanetetrahydropyran, and 2,5-disilanetetrahydrofuran, to deposit a dielectric layer comprising silicon, oxygen, and carbon on the substrate, wherein the dielectric layer has a carbon content of at least 1% by atomic weight and a dielectric constant of less than about 3;
• and
• depositing an oxygen doped silicon carbide layer on the dielectric layer by reacting an alkylsilane and oxygen in a plasma of an inert gas.

A method for processing a substrate, comprising:

• reacting an organosilicon compound selected from the group consisting of dimethylsilanediol, diphenylsilanediol, dimethyldimethoxysilane, diethyldiethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, 1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)propane, 1,3,5,7-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3,5-trisilanetetrahydropyran, and 2,5-disilanetetrahydrofuran to deposit a dielectric layer comprising silicon, oxygen, and carbon on the substrate;
• and
• depositing an oxygen doped silicon carbide layer on the dielectric layer.