Method for forming a via in a semiconductor device

A method for making a semiconductor device comprising the steps of:

• providing a semiconductor substrate having a conductive interconnect with a sidewall;
• depositing a blanket dielectric nitride layer over the semiconductor substrate, over the conductive interconnect, and along the sidewall of the conductive interconnect;
• depositing an oxide layer on the blanket dielectric nitride layer;
• dry etching the oxide layer to form a via over the conductive interconnect, using the blanket dielectric nitride layer as an etch stop;
• etching the blanket dielectric nitride layer to remove portions of the blanket dielectric nitride layer within the via, wherein etching the blanket dielectric nitride layer is performed anisotropically to maintain a portion of the blanket dielectric nitride layer along the sidewall of the conductive interconnect;
• and
• chemically vapor depositing a conductive material in the via using a source gas comprised of fluorine to make electrical contact to the conductive interconnect, wherein the portion of the blanket dielectric nitride layer along the sidewall of the conductive interconnect shields the conductive interconnect from exposure to fluorine from the source gas.

A method for making a semiconductor device comprising the steps of:

• providing a semiconductor substrate;
• depositing a metal layer over the semiconductor substrate;
• patterning and etching the metal layer to form a conductive interconnect having a base portion and a cap, the conductive interconnect also having a sidewall;
• forming a dielectric nitride layer over the conductive interconnect and immediately adjacent the sidewall of the conductive interconnect;
• forming a dielectric layer on the dielectric nitride layer;
• dry etching a via in the dielectric layer, the via overlying a portion of the conductive interconnect and exposing a portion of the dielectric nitride layer, without exposing the conductive interconnect;
• selectively removing the dielectric nitride layer exposed within the via while maintaining a portion of the dielectric nitride layer adjacent the sidewall of the conductive interconnect;
• and
• depositing a conductive material in the via using a source gas of the conductive material which includes fluorine, wherein during deposition, the sidewall of the conductive interconnect is protected from exposure to fluorine by the portion of dielectric nitride layer.