A supercritical fluid is a high-pressure medium that possesses both high diffusivity and solvent capabilities. Metal thin films can be deposited in supercritical fluids from an organometallic compound (precursor) through thermochemical reactions. In the present study, we used a technique, aimed at applying to the fabrication of through-silicon vias (TSVs), where copper thin films were deposited in silicon microholes 10 μm in diameter and 350 μm in depth. The temperature and pressure were varied from 180°C to 280°C and 1 MPa to 20 MPa, respectively. The maximum coating depth decreased with deposition temperature, whereas a peak maximum of the depth was observed at around 10 MPa. The temperature and pressure dependences on the coating depth were numerically studied. On the basis of the analysis, a deposition program was modified as to elongate the coating depth.