Ion milling device, ion source and ion milling method
View Patent ↗To provide an ion gun of a penning discharge type capable of achieving a milling rate which is remarkably higher than that in the related art, an ion milling device including the same, and an ion milling method. An ion generation unit includes a cathode that emits electrons, an anode that is provided within the ion generation unit and has an inner diameter of 5.2 mm or less, and magnetic-field generation means using a permanent magnet of which a maximum energy product ranges from 110 kJ/m 3 to 191 kJ/m 3 .
1. An ion milling device comprising:
an ion generator configured to cause electrons to collide with a gas supplied from an outside of the ion milling device and to generate ions; and
an acceleration electrode at which a voltage of 5 kV or more is applied as an electrode that accelerates the ions emitted from the ion generator, and that irradiates a sample with the accelerated ions so as to process the sample,
wherein the ion generator includes
a cathode from which the electrons are emitted;
an anode that is provided within the ion generator and has an inner diameter of 5.2 mm or less; and
a magnetic-field generator that generates a magnetic field within the ion generator by using a magnet having a maximum energy product ranging from 110 kJ/m 3 to 191 kJ/m 3 .
2. The ion milling device according to claim 1 ,
wherein the magnet is a samarium-cobalt magnet.
3. The ion milling device according to claim 1 ,
wherein a voltage of 6 kV or more is applied at the acceleration electrode.
4. The ion milling device according to claim 1 ,
wherein the ion generator is a penning type.
5. The ion milling device according to claim 1 ,
wherein a residual magnetic flux density remaining in a permanent magnet of the magnetic-field generator in an absence of a voltage being present at said anode of the ion generator ranges from 810 mT to 950 mT.
6. The ion milling device according to claim 1 ,
wherein a holding force of the magnetic-field generator ranges from 620 mT to 660 mT.
7. The ion milling device according to claim 1 ,
wherein a shape of the anode is a cylindrical shape, and an inner diameter of the anode is the same as a diameter of an outlet hole of the anode.
8. The ion milling device according to claim 1 ,
wherein a diameter of an outlet hole of the anode is smaller than an inner diameter of the anode.
9. The ion milling device according to claim 8 ,
wherein the diameter of the outlet hole of the anode is 4 mm.
10. An ion source that is used in an ion milling device that includes an ion generator which causes electrons to collide with a gas supplied from an outside of the ion milling device and that generates ions, and an acceleration electrode at which a voltage of 5 kV or more is applied as an electrode that accelerates the ions emitted from the ion generator, and that irradiates a sample with the accelerated ions so as to process the sample, the ion source comprising:
a cathode from which the electrons are emitted;
an anode which is provided within the ion generator, and has an inner diameter of 5.2 mm or less; and
a magnetic-field generator that generates a magnetic field within the ion generator by using a magnet having a maximum energy product ranging from 110 kJ/m 3 to 191 kJ/m 3 .
11. The ion source according to claim 10 ,
wherein the magnet is a samarium-cobalt magnet.
12. The ion source according to claim 10 ,
wherein a voltage of 6 kV or more is applied at the acceleration electrode.
13. The ion source according to claim 10 ,
wherein the ion source is a penning type.
14. The ion source according to claim 10 ,
wherein a residual magnetic flux density of a permanent magnet of the magnetic-field generator in an absence of a voltage being present at said anode of the ion generator ranges from 810 mT to 950 mT.
15. The ion source according to claim 10 ,
wherein a holding force of the magnetic-field generator ranges from 620 mT to 660 mT.
16. An ion milling device comprising:
an ion generator configured to cause electrons to collide with a gas supplied from an outside of the ion milling device and to generate ions; and
an acceleration electrode at which a voltage of 5 kV or more is applied as an electrode that accelerates the ions emitted from the ion generator, and that irradiates a sample with the accelerated ions so as to process the sample,
wherein the ion generator includes
a cathode from which the electrons are emitted;
an anode that is provided within the ion generator and has an inner diameter of 5.2 mm or less; and
a magnetic-field generator that generates a magnetic field on a central axis of the ion generator in a range of 140 mT to 160 mT.
17. The ion milling device according to claim 16 ,
wherein a voltage of 6 kV or more is applied at the acceleration electrode.
18. An ion milling method comprising:
an emission step of emitting electrons from a cathode;
an ion generation step of causing the electrons to collide with a gas supplied, from an outside of a milling device, on an inside of an anode having an inner diameter of 5.2 mm or less and generating ions;
a magnetic-field generation step of causing the ions to act on a magnetic field generated by a magnet having a maximum energy product ranging from 110 kJ/m 3 to 191 kJ/m 3 ;
an acceleration step of applying a voltage of 5 kV or more to the ions and accelerating the ions; and
a processing step of irradiating a sample with the accelerated ions so as to process the sample.
19. The ion milling method according to claim 18 ,
wherein the acceleration step is an acceleration step of applying a voltage of 6 kV or more to the ions and accelerating the ions.
20. The ion milling method according to claim 18 ,
wherein the magnetic-field generation step is a step of generating a magnetic field on a central axis of an ion generation unit in a range of 140 mT to 160 mT.