Patent ID: 8921235

Claim:
A method of forming air gaps between adjacent raised features on a substrate, the method comprising: forming a first silicon-containing film using a flowable deposition process, the first silicon-containing film filling a lower region between the adjacent raised features; forming a carbon-containing material on top of the first silicon-containing film in between the adjacent raised features using a flowable deposition process; forming a second silicon-containing film over the carbon-containing material, the second silicon-containing film filling an upper region between the adjacent raised features and extending over the adjacent raised features; and curing the carbon-containing material and the first and second silicon-containing films at an elevated temperature for a period of time to form the air gaps between the adjacent raised features; wherein the adjacent raised features create a trench and the flowable deposition process fills the trench from a bottom of the trench upwards towards a top of the trench; and wherein the first silicon-containing film forms a thin layer on sidewalls of the adjacent raised features, the thin layer extending from a bottom of the trench along only a lower portion of the sidewalls.