Beam Plasma Source

Patent metadata

Field	Value
Publication number	US-2026011530-A1
Application number	US-202418763453-A
Country	US
Kind code	A1
Filing date	Jul 3, 2024
Priority date	Jul 3, 2024
Publication date	Jan 8, 2026
Grant date	—

Abstract

A broad beam plasma or ion source is provided, which includes an anode pole extending beyond the top surface of the cathode. A further aspect of a broad ion source includes magnets and magnetic shunts which create convex magnetic flux across and above the anode pole, which intercepts a significant portion of the magnetic flux. In another aspect, a broad beam ion source includes a magnetic surrounding cathode that prevents the magnetic flux from leaking out of the ion source. A further aspect provides a broad beam plasma source which is excited by combined DC and RF powers to create ions and reactive species to interact with specimen. Yet in a further aspect, a broad beam ion source operates simultaneously with another deposition source at the same internal pressure in a vacuum chamber for making high-quality thin films.

First claim

What is claimed is:

1 . An ion source comprising:
an anode pole disposed between a center cathode and a surrounding cathode, with the anode pole having a surface extending above a center cathode surface and the surrounding cathode; and a set of magnets and magnetic shunts that create substantially convex magnetic flux lines across and above the surface of the anode pole, wherein the surrounding cathode further comprises an upper surrounding cathode and a lower supporting cathode, wherein the upper surrounding cathode includes an inner portion disposed adjacent to and beneath the anode pole surface extending above the center cathode surface and an outer portion disposed outboard of the inner portion and mounted to the lower supporting cathode, and wherein the lower supporting cathode is further mounted to a cathode housing.

2 . The ion source of claim 1 , wherein the center cathode and the upper surrounding cathode are non-magnetic materials and the lower supporting cathode is magnetic steel.

3 . The ion source of claim 1 , wherein the anode is powered with combined direct current (DC) and radio frequency (RF) power supplies to generate a beam of ions.

4 . The ion source of claim 3 , wherein the RF frequency in the range from 0.1 to 27 MHz.

5 . The ion source of claim 3 , wherein the DC voltage is adjustable from 0 to 300 V.

6 . The ion source of claim 3 , wherein a beam of ions is emitted from a face of the anode, the ions being substantially uniformly distributed around an ion emission axis when viewed in cross-section.

7 . The ion source of claim 3 , wherein at least one of the anode pole, the set of magnets and magnetic shunts, the surrounding cathode, and the cathode housing are circular or linearly elongated in a direction substantially perpendicular to the ion emission axis, to produce a linearly broad beam of ions.

8 . A method comprising:
controlling the ion energy of an ion source using a combination of DC and RF power supplies; and controlling, using the combination of DC and RF power supplies, the ion flux density of the ion source.

9 . The method of claim 8 , further comprising:
disposing a pole of an anode between a center cathode and a surrounding cathode, wherein the anode pole surface extends above a surface of the center cathode and an adjacent surface of the surrounding cathode; and disposing a set of magnets and shunts relative to the anode and cathodes to generate convex magnetic flux lines across and above the surface of the anode pole.

10 . The method of claim 9 , further comprising:
constructing the center cathode of a non-magnetic material; constructing a top part of the surrounding cathode of a non-magnetic material; and constructing a lower part of the surrounding cathode of a magnetic steel.

11 . The method of claim 8 , further comprising controlling the ion energy output by adjusting the DC voltage from 0 to 300 V and controlling the ion flux density by adjusting the RF power frequency from 0.1 To 27 MHz.

12 . A process for generating a beam of ions comprising:
establishing a background pressure in the vacuum chamber in a range of 0.0001 to 10 Torr using a vacuum pump and introducing at least one processing gas into a vacuum chamber using a mass flow controller; applying combined DC and RF power from at least one power supply to an ion source disposed within the vacuum chamber with the DC voltage adjustable from 0 to 300 V and an RF frequency in the range of 0.1 to 27 MHz to generate an ion beam; orienting the ion beam generated by the ion source toward a specimen disposed in the vacuum chamber.

13 . The process of claim 12 , wherein the ion source further comprises:
configuring an anode pole located between a center cathode and a surrounding cathode with the anode pole surface extending above the center cathode surface and the inner part of the surrounding cathode surface; and configuring a set of magnets and shunts creating convex magnetic flux lines across and above the surface of the anode pole.

14 . The process of claim 13 , further comprising constructing the center cathode and the top part of the surrounding cathode of non-magnetic materials and constructing the lower part of the surrounding cathode of magnetic steel.

15 . The process of claim 12 , further comprising flowing part of the processing gas through the ion source at an adjustable flow rate starting from a 0 SCCM flow rate up to a predetermined process gas pressure flow rate, wherein introducing the processing gas into the vacuum chamber beginning at the 0 SCCM flow rate is via an additional process gas port.

16 . The process of claim 12 , further comprising decomposing, by the ion source, a process gas into its constituent species and depositing, at least one of the species onto the specimen, forming a solid thin film on the specimen.

17 . (canceled)

18 . (canceled)

19 . The ion source of claim 1 , wherein the magnetic shunts are composed of a ferromagnetic material having a relative permeability greater than 100.

20 . The ion source of claim 3 , wherein a ratio of RF power to DC power is adjustable to fine-tune ion flux independently of ion energy.

21 . The ion source of claim 6 , wherein the emitted ion beam has a substantially sharp energy distribution peak with a typical full-width-at-half-maximum value of less than 25 eV.

22 . The ion source of claim 1 , wherein the anode pole is formed of a material selected from the group consisting of aluminum, stainless steel, titanium, molybdenum, tungsten, and graphite.

23 . The ion source of claim 1 , wherein the convex magnetic flux lines create a confinement zone that stabilizes plasma discharge during operation.

24 . An apparatus for depositing thin films on a specimen in a vacuum chamber comprising:
a physical vapor deposition source oriented toward the specimen; an ion source oriented toward the specimen, the ion source comprising: an anode having a pole disposed between a center cathode and a surrounding cathode, with the anode pole having a pole surface extending above the center cathode surface and a portion of the surrounding cathode; the surrounding cathode having an upper surrounding part and a lower supporting part, wherein the anode pole extends above an inner portion of the upper surrounding part of the surrounding cathode; a set of magnets and magnetic shunts to generate convex magnetic flux lines across and above the anode pole surface; and a gas flow control unit configured to direct gases either entirely into the vacuum chamber or partially through the ion source to establish a working pressure and facilitate plasma discharge.

25 . The apparatus of claim 24 , wherein ion source comprises a center cathode and an upper surrounding cathode that are constructed of non-magnetic materials and a lower supporting part of the surrounding cathode that is constructed of magnetic steel.

26 . The apparatus of claim 24 , wherein the ion source is powered by a combined direct current (DC) and radio frequency (RF) power supplies.

27 . The apparatus of claim 26 , wherein the ion source includes an RF power supply operating at a frequency in the range of 0.1 to 27 MHz.

29 . The apparatus of claim 26 , wherein the ion source includes a DC power supply providing a voltage in the range of 0 to 300 V.

30 . The apparatus

Assignees

• Univ Michigan State
• Scion Plasma Llc

Inventors

• Fan Qi Hua
• Stevenson David
• Zhou Li Qin

Classifications

• H01J2237/332

  Coating · CPC title

• H01J2237/0815

  Methods of ionisation · CPC title

• H01J2237/081

  Sputtering sources · CPC title

• H01J2237/083

  Beam forming · CPC title

• C23C14/35

  by application of a magnetic field, e.g. magnetron sputtering {(C23C14/3457 takes precedence)} · CPC title