Patent ID: 7615482

Claim:
A method for improving the interfacial strength between different layers, the method comprising the steps of: a) providing a substrate having a layer of dielectric or conductive material; b) introducing a flow of oxygen and SiCOH precursor into a chamber for a first time period so as to form a layer of oxide on the layer of dielectric or conductive material, the oxide layer having essentially no carbon; c) maintaining the flow of oxygen while gradually increasing the flow of the SiCOH precursor to a predetermined amount while also introducing and gradually increasing the flow of a porogen precursor to a predetermined amount into the chamber for a second time period so as to form a graded transition layer on the oxide layer, the graded transition layer having essentially no carbon at the interface with the oxide layer and gradually increasing carbon towards a porous SiCOH layer; and d) maintaining the flow of SiCOH precursor and porogen precursor at the predetermined amount in the chamber for a third time period while abruptly reducing the flow of oxygen to a predetermined value so as to form a porous SiCOH layer on the graded transition layer, the porous SiCOH layer having an homogenous composition throughout the layer.