Diffusion enhanced ion plating for copper fill

A method of sputter filling copper into a hole formed in a dielectric layer in a substrate, comprising the steps of:

• a first step of depositing copper into said hole including holding a temperature of said substrate at a first temperature of less than 100° C. and biasing said substrate with a first bias voltage;
• and
• a subsequent second step of depositing copper into said hole and filling it including holding said temperature of said substrate at a second temperature greater than said first temperature and biasing said substrate with a second bias voltage less than said first bias voltage.

A method of sputtering copper into a hole formed in a substrate, comprising the steps of:

• applying a voltage to a copper target to discharge a working gas within a plasma sputter reactor into a plasma, whereby copper is sputtered from said target onto a substrate in opposition to said target;
• and
• while sputtering said copper from said target onto said substrate, introducing through a gas supply port a diffusion promoting gas into said chamber selected from the group consisting of hydrogen and helium to create a plasma of said gas to thereby increase a diffusion of said copper in said hole.

A method of filling a hole formed in a substrate with copper, comprising the steps of:

• a first step of sputtering copper into said hole while applying a negative DC bias of a first magnitude to said substrate;
• and
• a second step of sputtering copper into and filling said hole while during at least a portion of said second step of applying a negative DC bias of a second magnitude less than said first magnitude.