Contact Formation Method and Related Structure

A method, comprising:

• forming a first contact plug in contact with a top side of a substrate region along a frontside surface of a substrate and a second contact plug in contact with a bottom side of the substrate region along a backside surface of the substrate;
• modulating a grain size of a first metal layer used to form each of the first and second contact plugs;
• and
• after modulating the grain size of the first metal layer, forming a first via over the first contact plug along the frontside surface of the substrate and a second via over the second contact plug along the backside surface of the substrate;
• wherein a phase of a second metal layer used to form each of the first and second vias includes an alpha phase.

A semiconductor device, comprising:

• a substrate;
• a contact plug portion of a backside contact structure, the contact plug portion formed along a backside surface of the substrate and contacting a substrate region, wherein the substrate region includes a source/drain region or a body contact region, wherein the contact plug portion includes a cobalt (Co) layer, and wherein a majority of the Co layer has a hexagonal close-packed (HCP) crystal structure;
• and
• a via portion of the backside contact structure, the via portion formed over the contact plug portion along the backside surface of the substrate, wherein the via portion includes a tungsten (W) layer formed in an alpha phase.