Method and apparatus for forming a barrier layer on a substrate

A method of forming a barrier layer on a substrate, comprising:

• sputter-depositing a tantalum nitride layer on a substrate having:
• a metal feature formed on the substrate;
• a dielectric layer formed over the metal feature;
• and
• a via formed in the dielectric layer so as to expose the metal feature, the via having side walls and a bottom, and a width of about 0.18 microns or less;
• wherein the tantalum nitride layer is deposited on the side walls and bottom of the via and on a field region of the dielectric layer;
• and
• wherein the tantalum nitride layer has a thickness of at least about 200 angstroms on the field region of the dielectric layer upon completion of the sputter-depositing of the tantalum nitride layer;
• and
• back sputtering at least a portion of the tantalum nitride layer from the bottom of the via of the substrate;
• and
• after the back sputtering step, sputter-depositing a tantalum layer on the substrate, the tantalum layer having a thickness of less than about 100 angstroms on the field region of the dielectric layer upon completion of the sputter-depositing of the tantalum layer;
• wherein sputter-depositing the tantalum nitride layer, back sputtering at least a portion of the tantalum nitride layer and sputter-depositing the tantalum layer are performed in a single deposition chamber.

A method of forming a barrier layer on a substrate, comprising:

• sputter depositing a tantalum nitride layer on the substrate having:
• a metal feature formed on the substrate;
• a dielectric layer formed over the metal feature;
• and
• a via formed in the dielectric layer so as to expose the metal feature, the via having side walls and a bottom, and a width of about 0.18 microns or less;
• wherein the tantalum nitride layer is deposited on the side walls and bottom of the via and on a field region of the dielectric layer;
• wherein the tantalum nitride layer has a thickness of at least about 200 angstroms on the field region of the dielectric layer upon completion of the sputter-depositing of the tantalum nitride layer;
• and
• wherein the sputter depositing of the tantalum nitride layer is performed within a high density plasma physical vapor deposition (HDPPVD) chamber employing a plasma having an ion density of at least 1010 ions/cm3, at a pressure of not more than about 10 mTorr using a target power of not more than about 40 kW and a pedestal bias power of not more than about 300 W;
• back sputtering at least a portion of the tantalum nitride layer from a bottom of the via of the substrate within the HDPPVD chamber at a pressure of not more than about 10 mTorr using a target power of not more than about 1000 W, and a pedestal bias power of not more than about 1000 W;
• and
• sputter-depositing a tantalum layer on the substrate at a pressure of not more than about 10 mTorr using a target power of not more than about 40 kW and a pedestal bias power of not more than about 300 W.