A method for depositing a low dielectric constant film is provided by
positioning a substrate within a processing chamber having a powered
electrode, and flowing into the processing chamber an initiation gas
mixture of a flow rate of one or more organosilicon compounds and a flow
rate of one or more oxidizing gases to deposit an initiation layer by
applying an RF power to the electrode. The organosilicon compound flow
rate is then ramped-up to a final flow rate to deposit a first transition
layer, upon which one or more porogen compounds is introduced and the
flow rate porogen compound is ramped up to a final deposition rate while
depositing a second transition layer. A porogen doped silicon oxide layer
is then deposited by flowing the final porogen and organosilicon flow
rates until the RF power is turned off.