Focused ion beam systems and methods of operation

1. A focused ion beam (FIB) system comprising:

a plasma generation chamber configured to contain a source gas that is radiated with microwaves to produce plasma, wherein the plasma generation chamber comprises:

a multicusp plasma confinement device having a first set of magnets to confine the plasma in radial and axial directions within the plasma generation chamber and a second set of magnets to facilitate formation of a plasma meniscus at an extraction end of the plasma generation chamber; and

a beam extraction chamber comprises:

a plasma electrode configured to receive ions from the plasma generation chamber;

a first Einzel lens configured to extract a focused ion beam from the confined plasma;

a beam limiting slit disposed adjacent to the first Einzel lens to reduce a size of the extracted focused ion beam; and

a second Einzel lens disposed adjacent to the beam limiting slit, configured to focus the extracted focused ion beam on a workpiece, wherein a beam spot formed on the workpiece by the focused ion beam has a diameter of about 10 microns to about 20 microns.

2. The system of claim 1 , wherein the plasma confinement device further comprises magnetic multipole ion reflecting walls having the first set of magnets with alternating polarity.

3. The system of claim 1 , wherein the plasma electrode is held at ground potential.

4. The system of claim 1 , wherein the plasma electrode comprises an aperture having a size of about 10 microns to about 1 mm.

5. The system of claim 1 , wherein the beam limiting slit has a diameter of about 0.2 mm to about 0.5 mm.

6. The system of claim 1 , wherein the beam extraction chamber is maintained at a pressure of about 10 −5 Torr to about 10 −6 Torr.

7. The system of claim 1 , wherein the microwaves have a frequency of about 4 GHz about 18 GHz.

8. The system of claim 1 , wherein the generated plasma has a plasma density of about 10 10 cm −3 to about 10 11 cm −3 .

9. The system of claim 1 , wherein each of the first Einzel lens and the second Einzel lens comprises a first electrode, a second electrode, and a third electrode, wherein the second electrode of each of the first Einzel lens and the second Einzel lens is held at ground potential.

10. The system of claim 9 , wherein the first electrode and the third electrode of each of the first Einzel lens and the second Einzel lens are maintained at a potential of about 1.5 kV to about 18 kV.

11. A method for generating focused ion beams, the method comprising:

radiating a source gas with microwaves have a frequency in a range of 4 GHz to about 18 GHz to generate plasma within a plasma generation chamber; confining the plasma in radial and axial directions within the plasma generation chamber and forming a plasma meniscus near an extraction end of the plasma generation chamber;

extracting focused ion beams from the confined plasma in a beam extraction chamber using a first Einzel lens;

limiting a size of the extracted focused ion beams using a beam limiting slit placed adjacent to the first Einzel lens; and

focusing the focused ion beams on a workpiece using a second Einzel lens disposed adjacent to the beam limiting slit.

12. The method of claim 11 , wherein confining the plasma in the radial and axial direction comprises applying multicusp magnetic fields within the plasma generation chamber.

13. The method of claim 12 , further comprising tailoring a spatial distribution of the applied magnetic fields to form the plasma meniscus adjacent to the extraction end of the plasma generation chamber.

14. A focused ion beam (FIB) system, the system comprising:

a plasma generation chamber configured to contain a source gas that is radiated with microwaves have a frequency in a range of 4 GHz to 18 GHz to produce plasma, wherein the plasma generation chamber comprises:

a multicusp plasma confinement device having a first set of magnets to confine the plasma in radial and axial directions within the plasma generation chamber and a second set of magnets to facilitate formation of a plasma meniscus at the extraction end of the plasma generation chamber; and

a beam extraction chamber comprises:

a plasma electrode configured to receive ions from the plasma generation chamber;

a first Einzel lens configured to extract a focused ion beam from the confined plasma;

a beam limiting slit disposed adjacent to the first Einzel lens to reduce a size of the extracted focused ion beam; and

a second Einzel lens disposed adjacent to the beam limiting slit, configured to focus the extracted beams onto a workpiece placed in a workpiece processing chamber.

15. The system of claim 14 , wherein the multicusp plasma confinement device is formed of magnetic multipole ion reflecting walls, each wall having at least six magnets with alternating polarity.

16. The system of claim 14 , wherein the plasma electrode comprises an aperture having a size of about 10 microns to about 100 microns.

17. The system of claim 11 , wherein the plasma generation chamber is maintained at a pressure of about 10 −3 Torr to about 10 −4 Torr.

18. The system of claim 14 , wherein the focused ion beams have an energy spread of equal to or less than about 8 eV.

19. The system of claim 14 , wherein the focused ion beams have a power density of about 5 W/cm 2 to about 10 W/cm 2 .

20. The system of claim 14 , wherein the focused ion beams have a focused beam current of equal to or greater than about 10 microamperes.