An apparatus for a plating process includes: an outer chamber; an inner chamber covered by the outer chamber; a rotatable holding mechanism configured to hold a substrate horizontally and installed in the inner chamber; a fluid supply unit configured to supply a plating solution to a preset position on the substrate; a gas supply device configured to generate a nonreactive gas and control a temperature of the nonreactive gas; a gas supply hole configured to supply the nonreactive gas into the outer chamber and provided in a top surface of the outer chamber; a plurality of gas inlet openings provided at a sidewall of the inner chamber and spaced apart at equal distances; and a rectifying plate disposed above the substrate and below the plurality of gas inlet openings inside the inner chamber, the rectifying plate having a plurality of rectifying holes uniformly disposed in the rectifying plate.