# US 12,760,407 B2 · Sputtering apparatus and deposition method of tungsten film

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- Number: US 12,760,407 B2
- Document ID: US12760407B2
- Status: Granted
- Kind: B2
- Application number: 19/189,640
- Filed: 2025-04-25
- Published: 2026-01-01
- Granted: 2026-10-13
- Earliest claimed: 2024-07-01
- Assignees: Ulvac, Inc.
- Applicants: Ulvac, Inc.
- Inventors: Yutaka Nakamitsu
- Web page: https://patentgrep.com/patent/US12760407B2

## CPC

- C23C 14/3435: {Applying energy to the substrate during sputtering}
- C23C 14/14: Metallic material, boron or silicon
- C23C 14/3407: {Cathode assembly for sputtering apparatus, e.g. Target}
- C23C 14/50: Substrate holders
- H01J 37/3441: {Dark space shields}
- H01J 2237/332: Coating
- H10P 14/418: {the conductive layers comprising transition metals}
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A substrate stage holding a substrate to be treated in a vacuum chamber in which a target made of tungsten is mounted and a high-frequency power source supplying a high-frequency electric power to the substrate stage are provided. When a first plasma atmosphere is generated in the vacuum chamber, and sputtered particles generated by sputtering the target are adhered and accumulated on the substrate so that a tungsten film is deposited, a second plasma atmosphere is generated by supplying the high-frequency electric power to the substrate stage, and plus ions in the first plasma atmosphere are also caused to collide with the substrate. Provided that an area of a substrate holding surface of the substrate stage functioning as one electrode and an inner-surface area of the vacuum chamber functioning as the other electrode of the second plasma atmosphere are defined as an anode area and a cathode area, respectively.

## Claims

### Claim 1

A sputtering apparatus, comprising:
a substrate stage holding a substrate to be treated in a vacuum chamber in which a target made of tungsten is mounted; and
a high-frequency power source supplying a high-frequency electric power to the substrate stage,
wherein the sputtering apparatus is configured that when a first plasma atmosphere of a rare gas is generated in the vacuum chamber of a vacuum atmosphere, and sputtered particles generated by sputtering the target are adhered and accumulated on the substrate to be treated held by a substrate holding surface of the substrate stage so that a tungsten film is deposited, a second plasma atmosphere of capacity-coupling type is generated in the vacuum chamber by supplying the high-frequency electric power to the substrate stage functioning as a first electrode, and plus ions ionized in the first plasma atmosphere are also caused to collide with the substrate to be treated, and
wherein the sputtering apparatus further comprises a shield unit at a ground potential surrounding a deposition space between the target and the substrate stage, the shield unit functioning as a second electrode, and
wherein the sputtering apparatus is further configured that provided that an area of the 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, a ratio of the anode area to the cathode area is set in a range of 4.0 to 6.0,
wherein the shield unit has a shield plate placed around the substrate stage, and in a surface of the shield plate 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.

### Claim 2

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.