Stacked lens structure and method of use thereof for preventing electrical breakdown
View Patent ↗A micro-electrical system, such as a lens stack for use in a scanning electron microscope, analysis tool, etc., comprises recesses and/or serrations that increase the surface path breakdown, thereby increasing reliability and enabling high voltage operations.
1. An electron beam column lens stack, comprising:
two conductive layers; and
an insulator layer between the two conductive layers;
wherein the conductive layers and the insulator layer form a recess that increases the breakdown path.
2. The lens stack of claim 1 , wherein the recess is at a sidewall of the lens stack.
3. The lens stack of claim 1 , wherein the conductive layers and the insulator layer form a plurality of recesses at sidewalls of the lens stack.
4. The lens stack of claim 3 , wherein a first recess in one of the conductive and insulator layers is perpendicular to a second recess in another layer.
5. The lens stack of claim 3 , wherein the conductive layers are recessed with respect to the insulator layer at each conductor layer edge.
6. The lens stack of claim 1 , wherein the conductive layers and the insulator layer form apertures and recesses within the conductive and insulator layers.
7. The lens stack of claim 1 , wherein the conductive layers and the insulator layer form apertures within the layers and further form serrations extending outwards from the apertures.
8. The lens stack of claim 1 , wherein the conductive layers form cutouts therein and the insulator layer is shaped to form an aperture therein, wherein one of the conductive layers has an air-bridge that spans one of the cutouts and is suspended over the aperture.
9. The lens stack of claim 1 , wherein the conductive layers form cutouts therein that increase surface breakdown.
10. The lens stack of claim 1 , each conductive layer having isolated conductive regions, the regions formed by recessed and trenches located at edges of the conductive layers.
11. The lens stack of claim 10 , wherein the layers form apertures and vias therein and wherein the vias or the apertures are increasingly smaller from top to bottom.
12. A scanning electron microscope incorporating the lens stack of claim 1 .
13. A lithography tool incorporating the lens stack of claim 1 .
14. An analysis tool incorporating the lens stack of claim 1 .
15. An inspection tool incorporating the lens stack of claim 1 .
16. A method, comprising:
generating an electron beam;
focusing the beam with an electron beam column incorporating a lens stack, the lens stack having two conductive layers and an insulator layer between the two conductive layers, wherein the conductive layers and the insulator layer form a recess that increases the breakdown path; and
scanning the beam over a target.
17. The method of claim 16 , wherein the recess is at a sidewall of the lens stack.
18. The method of claim 16 , wherein the conductive layers and the insulator layer form a plurality of recesses at sidewalls of the lens stack.
19. The method of claim 18 , wherein a first recess in one of the conductive and insulator layers is perpendicular to a second recess in another layer.
20. The method of claim 18 , wherein the conductive layers are recessed with respect to the insulator layer at each conductor layer edge.
21. The method of claim 16 , wherein the conductive layers and the insulator layer form apertures and recesses within the conductive and insulator layers.
22. The method of claim 16 , wherein the conductive layers and the insulator layer form apertures within the layers and further form serrations extending outwards from the apertures.
23. The method of claim 16 , further comprising:
collecting electrons or photons from the target; and
generating an image based on the collected electrons or photons.
24. The method of claim 16 , wherein the target is a wafer and wherein the scanning imprints a pattern onto the wafer for a circuit.
25. The method of claim 16 , wherein the conductive layers form cutouts therein and the insulator layer is shaped to form an aperture therein, wherein one of the conductive layers has an air-bridge that spans one of the cutouts and is suspended over the aperture.
26. The method of claim 16 , wherein the conductive layers form cutouts therein that increase surface breakdown.
27. The method of claim 16 , each conductive layer having isolated conductive regions, the regions formed by recessed and trenches located at edges of the conductive layers.
28. The method of claim 16 , wherein the layers form apertures and vias therein and wherein the vias or the apertures are increasingly smaller from top to bottom.
29. A electron beam column lens stack, comprising:
two conductive layers; and
an insulator layer between the two conductive layers;
wherein the conductive layers and the insulator layer form at least one aperture within the layers and form serrations, which increase the surface breakdown path and extend outward from the at least one aperture.