Sputtering apparatus and deposition method of tungsten film

A deposition method of a tungsten film, comprising:

• a step of introducing a rare gas into a vacuum chamber in which a target made of tungsten is mounted, generating a first plasma atmosphere of the rare gas in the vacuum chamber of a vacuum atmosphere by supplying an electric power to the target, scattering sputtered particles generated by sputtering a sputtering surface of the target, and depositing a tungsten film by adhering and accumulating the sputtered particles on a substrate to be treated held by a substrate stage;
• and
• a step, during deposition, of supplying a high-frequency electric power to the substrate stage functioning as a first electrode and generating a second plasma atmosphere of a capacity-coupling type in the vacuum chamber, and also causing ions ionized in the first plasma atmosphere to collide with the substrate to be treated,
• wherein, when the second plasma atmosphere is generated, a shield unit at a ground potential surrounding a deposition space between the target and the substrate stage functions as a second electrode,
• wherein provided that an area of a substrate holding surface of the substrate stage to which the high-frequency electric power is supplied is defined as a cathode area and an inner-surface area of the vacuum chamber and the shield unit functioning as the second electrode of the second plasma atmosphere is defined as an anode area, the deposition method of the tungsten film further comprises a step of adjusting a self-bias potential that is a negative DC component of a potential of the substrate to be treated independently of the high-frequency electric power supplied to the substrate stage by changing a ratio of the anode area to the cathode area in a range of 4.0 to 6.0,
• wherein, in a surface of a shield plate of the shield unit facing the deposition space, a first surface portion disposed on a substrate stage side has a lower impedance than a second surface portion other than the first surface portion, and the second surface portion is covered with an insulator while the first surface portion remains exposed to the deposition space, such that the anode area is reduced by excluding an area corresponding to the second surface portion from the anode area while maintaining an area corresponding to the first surface portion in the anode area.