Methods for forming metal wiring layers and metal interconnects and metal interconnects formed thereby

A method for forming a metal wiring layer of a semiconductor device comprising the steps of:

• forming an interlayer dielectric layer pattern having a contact hole therein, on the semiconductor substrate;
• forming a barrier metal layer at a sidewall and bottom of the contact hole and on the interlayer dielectric layer pattern;
• forming a metal seed layer so as to overhang an entrance of the contact hole and make an entrance width of the contact hole smaller than a bottom width of the contact hole;
• forming an anti-nucleation layer on the metal seed layer formed at a top surface of the interlayer dielectric layer pattern;
• continuously forming a metal liner layer on exposed portions of the metal seed layer and the barrier metal layer where the anti-nucleation layer was not deposited;
• forming a metal layer on the anti-nucleation layer;
• and
• forming a metal wiring layer in the contact hole by reflowing the metal layer so as to fill the contact hole.

A metal interconnect, comprising:

• a semiconductor substrate;
• an electrically insulating layer having a contact hole therein, on the substrate;
• an electrically conductive seed layer that extends on a sidewall of the contact hole and on a portion of an upper surface of the electrically insulating layer extending adjacent the contact hole and is absent from a floor of the contact hole, and is sufficiently thick along an upper portion of the sidewall and sufficiently thin along a lower portion of the sidewall that an upper portion of the contact hole is partially constricted by the electrically conductive seed layer and a constricted contact hole is thereby defined;
• an anti-nucleation layer that extends on a portion of the electrically conductive seed layer extending outside the constricted contact hole, but not on a bottom of the constricted contact hole;
• a metal liner on a portion of the electrically conductive seed layer that defines a sidewall of the constricted contact hole;
• and
• a metal interconnect layer that extends into the constricted contact hole and electrically contacts the metal liner and the anti-nucleation layer.

A method of forming a metal interconnect, comprising the steps of:

• forming an electrically insulating layer having a contact hole therein, on a substrate;
• depositing an electrically conductive barrier metal layer along a sidewall and bottom of the contact hole and on an upper surface of the electrically insulating layer, using a first composite gas having a first composition that provides a first degree of step coverage to the barrier metal layer;
• then
• depositing an electrically conductive seed layer that extends on the barrier metal layer and in the contact hole, using a second composite gas having a second composition that provides a second degree of step coverage to the seed layer that is less than the first degree of step coverage and causes the seed layer to overhang the contact hole;
• then
• forming an anti-nucleation layer on a portion of the seed layer extending outside the contact hole;
• then
• forming a metal liner on a portion of the seed layer extending within the contact hole;
• and then
• reflowing a metal interconnect layer into the contact hole.