Method and Apparatus for Ion Milling

• US 20080302657A1
• Filed: 06/12/2008
• Published: 12/11/2008
• Est. Priority Date: 03/05/2007
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Neuman, George A., Luten, Henry A., Olesen, Niels Alfred
• Granted Patent: US 10,017,847 B2
• Time in Patent Office: Days
• US Class Current: 204/298.36
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 14/185 by cathodic sputtering
• CPC Class Codes: C23C 14/5833 Ion beam bombardment
• CPC Class Codes: C23C 14/5873 Removal of material
• CPC Class Codes: G02F 1/163 Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor

Abstract

The present invention relates to methods and apparatus for ion milling, and more particularly relates to methods and apparatus for smoothing a surface using ion milling.

Claims

1. An anode layer ion source comprising:

an inner cathode;

an outer cathode disposed around said inner cathode with a gap therebetween to define an elongated loop having straight portions joined by turns;

an anode disposed proximate said gap between said cathodes and behind said cathodes relative to ejection of electrons, wherein electrons travel around said loop in response to an electric field appearing between said anode and said cathodes, and a magnetic field appearing between said cathodes; and

means for reducing electron loss at the turns in said loops.

2. The anode layer ion source of claim 1, wherein said means for confining said electrons comprises configuring said anode and said cathodes such that an ion beam is generated that is emitted at an angle relative to a central axis of the ion source, wherein the angle is at least about 15 degrees.

3. The anode layer ion source of claim 2, wherein the angle is at least about 30 degrees.

4. The anode layer ion source of claim 3, wherein the angle is at least about 45 degrees.

5. The anode layer ion source of claim 4, wherein the angle is at least about 60 degrees.

6. The anode layer ion source of claim 1, wherein the central axis of the ion source is normal to a surface to be exposed to an ion beam from the ion source.

7. The anode layer ion source of claim 1, wherein said means for confining said electrons comprises an arrangement of magnets underlying said outer cathode around the perimeter of the turn.

8. The anode layer ion source of claim 1, wherein said means for confining said electrons comprises an arrangement of magnets underlying at least one of said cathodes, where an angle of orientation of the magnetic field is selected to reduce loss of the electrons in the turn.

9. The anode layer ion source of claim 1, wherein said means for confining said electrons comprises an arrangement of magnets underlying said inner cathode, where said magnets closest the turn have a different magnetic strength.

10. The anode layer ion source of claim 1, wherein the strength of the magnetic field is at least about 2600 gauss

11. An anode layer ion source comprising:

a magnetic backplane;

a plurality of pairs of cathodes with a gap therebetween to define an elongated loop having straight portions joined by turns; and

a plurality of anodes, wherein one of said anodes underlies the gap between each of said pairs of cathodes,

wherein electrons travel around the plurality of loops defined by the gaps of said plurality of pairs of cathodes, and wherein said magnetic backplane is common to all of said pairs of cathodes.

12. The anode layer ion source of claim 11 and further comprising means for confining said electrons at the turns in said loops.

13. The anode layer ion source of claim 11, wherein electrons travel around said loops in response to electric fields appearing between said anodes and respective pairs of said cathodes, and in response to magnetic fields appearing between said pairs of cathodes, wherein the strength of the magnetic field is at least about 2600 gauss.

14. An anode layer ion source comprising:

an inner cathode;

an outer cathode disposed around said inner cathode with a gap therebetween to define an elongated loop having straight portions joined by turns; and

an anode disposed below said gap between said cathodes, wherein electrons travel around said loop in response to an electric field appearing between said anode and said cathodes, and a magnetic field appearing between said cathodes, wherein the strength of the magnetic field is at least about 2600 gauss.

15. The anode layer ion source of claim 14, wherein the magnetic strength of the magnetic field is at least about 5000 gauss.

16. The anode layer ion source of claim 15, wherein the magnetic strength of the magnetic field is at least about 7500 gauss.

17. The anode layer ion source of claim 14, wherein the strength of the magnetic field is at least about 2600 gauss at both turns of said loop.

18. The anode layer ion source of claim 14, wherein the strength of the magnetic field is at least about 2600 gauss at substantially all locations along said loop.

19. The anode layer ion source of claim 14, wherein the strength of the magnetic field is greater at both turns of said loop than at other portions of said loop.

20. The anode layer ion source of claim 14 and further comprising a row of magnets underlying said inner cathode, wherein the strength of the magnetic field is increased by providing using magnets of with sufficient strength to create the magnetic field of at least about 2600 gauss.

21. The anode layer ion source of claim 14 and further comprising a first row of magnets underlying said inner cathode;

and a second row of magnets underlying said outer cathode.