Atomically thin highly resistive barrier layer in a copper via

A process of filling copper into a vertical interconnection hole extending through an inter-level dielectric layer formed in a substrate and having sides and a bottom, comprising the steps of:

• coating sides and a bottom of said hole with a barrier layer of a metal oxide or nitride having an electrical resistivity greater than 500 microohm-cm and a thickness on said sides of less than 5 nm;
• removing said barrier layer from said bottom;
• sputtering a copper target opposed to said substrate to deposit a copper layer on at least said sides;
• and
• then electroplating copper into said hole.

A copper via structure, comprising:

• a lower dielectric layer having a copper feature formed in its surface;
• an upper dielectric layer formed over said lower dielectric layer and having a hole formed therethrough in an area of said copper feature;
• a barrier layer comprising a metal oxide formed on sides of said hole but not on a bottom of said hole facing said copper feature;
• and
• copper filled into said hole and contacting said copper feature.

A copper via structure, comprising:

• a lower dielectric layer having a copper feature formed in its surface;
• an upper dielectric layer formed over said lower dielectric layer and having a hole formed therethrough in an area of said copper feature;
• a barrier layer comprising a metal oxide or nitride formed on sides of said hole to a thickness of no more than 5 nm but not on a bottom of said hole facing said copper feature;
• and
• copper filled into said hole and contacting said copper feature.

A copper via structure, comprising:

• a lower dielectric layer having a conductive feature formed in its surface;
• an upper dielectric layer formed over said lower dielectric layer and having a hole formed therethrough in an area of said conductive feature;
• a barrier layer comprising tantalum nitride formed on sides of said hole to a thickness of greater than 0.5 nm and no more than 5 nm but not on a bottom of said hole facing said conductive feature;
• and
• copper filled into said hole.