Integrated circuit device and method of manufacturing

An integrated circuit (IC) device, comprising:

• a device stack comprising:
• a bottom semiconductor device, and
• a top semiconductor device stacked over the bottom semiconductor device along a direction;
• a top contact structure over and in electrical contact with a source/drain of the top semiconductor device;
• a bottom contact structure under and in electrical contact with a source/drain of the bottom semiconductor device;
• a conductor co-elevational with, spaced from, and thinner than, the bottom contact structure;
• a via interconnect extending between and electrically coupling the top contact structure and the conductor;
• and
• a back side power rail under and electrically coupled to the conductor.

A method, comprising:

• forming a via interconnect in a dielectric structure which is in contact with a gate structure of a device stack;
• forming a top contact structure over and in electrical contact with
• a source/drain of a top semiconductor device of the device stack, and
• a top surface of the via interconnect;
• forming a back side via over and in electrical contact with a bottom surface of the via interconnect;
• and
• depositing and patterning a back side metal layer to obtain a back side power rail over and in electrical contact with the back side via.