Patent ID: 7686926

Claim:
A process performed in a sputter chamber for depositing a barrier layer in a hole formed in a dielectric layer of a substrate placed on a pedestal electrode in said chamber in opposition to a target comprising a refractory metal, wherein the sputter chamber is arranged around an axis and includes a pedestal electrode for supporting the substrate, a planar target in opposition to the pedestal electrode, an RF coil wrapped around the axis, first and second electromagnetic coils wrapped around the axis at two different respective axial positions, and a third electromagnetic coil wrapped around the axis at a radial position different from that of the first electromagnetic coil, no pair of the first, second and third electromagnetic coils being coincident, at least one of the first, second, and third electromagnetic coils being disposed radially outside of the RF coil at an axial position occupied by the RF coil, said process comprising the sequentially performed steps of: (a) a nitride deposition step including applying a first level of DC power to said target to excite a plasma to sputter said target, applying a first level of RF power to said pedestal electrode, powering said first and second electromagnetic coils to produce opposed magnetic fields, and flowing nitrogen gas into said chamber to form a nitride of said refractory metal on said substrate; (b) a refractory metal deposition step including applying a second level of DC power to said target to excite a plasma to sputter said target; applying a second level of RF power to said pedestal electrode; powering said first and second electromagnetic coils to produce opposed magnetic fields, and substantially ceasing flowing nitrogen gas into said chamber; and (c) an etching step including flowing argon into said chamber, applying RF power to said RF coil to excite said argon into a plasma, powering the first and third electromagnetic coils to produce opposed magnetic fields, wherein magnetic field distributions produced by the first, second, and third electromagnetic coils differ between the refractory metal deposition step and the etching step, and applying a third level of RF power to said pedestal electrode to thereby etch the substrate with the plasma of argon.