Semiconductor device with cut metal gate and method of manufacture

A semiconductor device comprising:

• a first fin and a second fin extending from a semiconductor substrate;
• a shallow trench isolation (STI) region around the first fin and the second fin;
• a first source/drain region in the first fin;
• a second source/drain region in the second fin;
• an interlayer dielectric (ILD) over the STI region and around the first source/drain region and the second source/drain region;
• a dielectric plug extending through the ILD and the STI region into the semiconductor substrate, wherein the dielectric plug has a width that decreases in a direction toward the semiconductor substrate;
• and
• a source/drain contact electrically connected to the first source/drain region and the second source/drain region, wherein the source/drain contact overlies the dielectric plug.

A semiconductor device comprising:

• a semiconductor substrate;
• a shallow trench isolation (STI) region over the semiconductor substrate;
• a first metal gate and a second metal gate over the STI region, wherein the first metal gate extends along a top surface and sidewalls of a first semiconductor fin, and wherein the second metal gate extends along a top surface and sidewalls of a second semiconductor fin;
• and
• a dielectric plug separating the first metal gate from the second metal gate, wherein the dielectric plug extends along a top surface and sidewalls of a portion of the semiconductor substrate, and wherein a width of the dielectric plug continuously decreases in a direction towards a bottom surface of the semiconductor substrate.