Use of cyclic siloxanes for hardness improvement

Abstract

A method for depositing a low dielectric constant film having a dielectric constant of about 3.5 or less is provided by blending one or more cyclic organosilicon compounds, one or more aliphatic organosilicon compounds, and one or more low molecular weight aliphatic hydrocarbon compounds. In one aspect, a gas mixture comprising one or more cyclic organosilicon compounds, one or more aliphatic organosilicon compounds, one or more aliphatic hydrocarbon compounds, one or more oxidizing gases, and a carrier gas is reacted at conditions sufficient to deposit a low dielectric constant film on a substrate surface.

What is claimed is:  
     
         1 . A method for depositing a low dielectric constant film having a dielectric constant of about 3.5 or less, comprising reacting a gas mixture comprising: 
 one or more cyclic organosilicon compounds;    one or more aliphatic organosilicon compounds; and    one or more low molecular weight aliphatic hydrocarbon compounds at conditions sufficient to deposit the low dielectric constant film on a substrate surface, the low dielectric constant film having a hardness of between about 1.0 gigaPascal and about 2.9 gigaPascal.    
     
     
         2 . The method of  claim 1 , wherein the one or more cyclic organosilicon compounds comprise at least one silicon-carbon bond.  
     
     
         3 . The method of  claim 1 , wherein the one or more aliphatic organosilicon compounds comprise a silicon-hydrogen bond.  
     
     
         4 . The method of  claim 1 , wherein the one or more cyclic organosilicon compounds is selected from the group consisting of 3,5-trisilano-2,4,6-trimethylene, 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS), octamethyl-cyclotetrasiloxane (OMCTS), 1,3,5,7,9-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, and hexamethylcyclotrisiloxane.  
     
     
         5 . The method of  claim 1 , wherein the one or more aliphatic organosilicon compounds is selected from the group consisting of methylsilane, dimethylsilane, trimethylsilane, dimethyldimethoxysilane, ethylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilanopropane, 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane (TMDSO), hexamethyldisiloxane (HMDS), 1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)propane, diethylsilane, propylsilane, vinylmethylsilane, 1,1,2,2-tetramethyldisilane, hexamethyldisilane, 1,1,2,2,3,3-hexamethyltrisilane, 1,1,2,3,3-pentamethyltrisilane, dimethyldisilanoethane, dimethyldisilanopropane, tetramethyldisilanoethane, and tetramethyldisilanopropane.  
     
     
         6 . The method of  claim 1 , wherein the one or more low molecular weight aliphatic hydrocarbons is selected from the group consisting of ethylene, propylene, acetylene, and butadiene.  
     
     
         7 . The method of  claim 1 , wherein the conditions comprise a power density ranging from about 0.03 W/cm 2  to about 4.8 W/cm 2 .  
     
     
         8 . The method of  claim 1 , wherein the conditions comprise a substrate temperature of about 100° C. to about 400° C.  
     
     
         9 . The method of  claim 1 , wherein the conditions comprise a pressure of about 3 Torr to about 7 Torr.  
     
     
         10 . The method of  claim 1 , wherein the conditions comprise radio frequency power delivered using mixed frequencies.  
     
     
         11 . A method for depositing a low dielectric constant film having a dielectric constant of about 3.5 or less, comprising reacting a gas mixture comprising: 
 one or more cyclic organosilicon compounds;    one or more aliphatic organosilicon compounds;    one or more low molecular weight aliphatic hydrocarbon compounds;    one or more oxidizing gases; and    a carrier gas at conditions sufficient to deposit the low dielectric constant film on a substrate surface, the low dielectric constant film having a hardness of between about 1.0 gigaPascal and about 2.9 gigaPascal.    
     
     
         12 . The method of  claim 11 , wherein the one or more cyclic organosilicon compounds comprise at least one silicon-carbon bond.  
     
     
         13 . The method of  claim 11 , wherein the one or more aliphatic organosilicon compounds comprise a silicon-hydrogen bond.  
     
     
         14 . The method of  claim 11 , wherein the one or more low molecular weight aliphatic hydrocarbons comprise an alkene or alkylene.  
     
     
         15 . The method of  claim 11 , wherein the one or more oxidizing gases is selected from the group consisting of oxygen (O 2 ), ozone (O 3 ), nitrous oxide (N 2 O), carbon. monoxide (CO), carbon dioxide (CO 2 ), water (H 2 O), peroxide (H 2 O 2 ), and combinations thereof.  
     
     
         16 . The method of  claim 11 , wherein the low dielectric constant film has a carbon content between about 10 and about 17 atomic percent.  
     
     
         17 . The method of  claim 11 , wherein the low dielectric constant film has an oxygen to silicon ratio of about 2:1, a silicon to carbon ratio of about 1:1, and a carbon to hydrogen ratio of about 1:3.  
     
     
         18 . A method for depositing a low dielectric constant film having a dielectric constant of about 3.5 or less, comprising reacting a gas mixture comprising: 
 octamethylcyclotetrasiloxane;    trimethylsilane; and    ethylene at conditions sufficient to deposit the low dielectric constant film on the substrate surface, the low dielectric constant film having a hardness of between about 1.0 gigaPascal and about 2.9 gigaPascal.    
     
     
         19 . The method of  claim 18 , wherein the gas mixture further comprises oxygen and helium.  
     
     
         20 . The method of  claim 18 , wherein the conditions comprise radio frequency power delivered using mixed frequencies.