A high density plasma chemical vapor deposition apparatus includes a vacuum chamber provided with an inlet and an outlet for a reaction gas; a suscepter positioned within the vacuum chamber to mount a wafer thereon, the suscepter having a wafer chuck at its upper surface to prevent the wafer from moving horizontally; a coil antenna surrounding the upper outer wall of the vacuum chamber; an RF generator for applying an RF power to the coil antenna; and a heating unit for heating the wafer mounted on the suscepter. Since the wafer 111 is heated in advance by the wafer heating unit, which is not proposed in the conventional HDP-CVD apparatus, the previously sputtered insulation material is restrained from re-depositing. Therefore, even though a gap has a high aspect ratio, it can be filled without a void.