NOVELTY - An interconnect structure is fabricated by forming a silicon carbide barrier layer on a metal layer of a substrate, by reacting a gas mixture comprising a silicon source, a carbon source, and a dopant. The silicon carbide layer has a compressibility that varies as a function of the amount of the dopant in the gas mixture.    USE - For the fabrication of interconnect structures.    ADVANTAGE - The method uses silicon carbide film having low dielectric constant and improved film characteristics.    DETAILED DESCRIPTION - Fabrication of interconnect structure comprises providing a substrate having a metal layer. A silicon carbide barrier layer is formed on the metal layer, by reacting a gas mixture comprising a silicon source, a carbon source, and a dopant. The silicon carbide layer has a compressibility that varies as a function of the amount of the dopant in the gas mixture. A first dielectric layer is formed on the silicon carbide barrier layer. A silicon carbide hard mask is formed on the first dielectric layer, by reacting a gas mixture comprising a silicon source, a carbon source, and a dopant. The silicon carbide hard mask has a compressibility that varies as a function of the amount of the dopant in the gas mixture. The silicon carbide hard mask is patterned to define vias. A second dielectric layer is formed on the patterned silicon carbide hard mask. The second dielectric layer is patterned to define interconnects which are positioned on the vias. The via pattern is transferred through the first dielectric layer using the silicon carbide hard mask. The vias and interconnects are filled with a conductive material.    INDEPENDENT CLAIMS are also included for:    (1) a computer storage medium containing a software routine that, when executed, causes a general purpose computer (110) to control a deposition chamber (100) using a layer deposition method; and    (2) a method of thin film deposition including positioning a substrate in a deposition chamber and forming silicon carbide layer on substrate.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic illustration of a wafer processing system.    Deposition chamber (100)    Computer (110)