Layered scanning charged particle microscope with differential pumping aperture
View Patent ↗A scanning charged particle apparatus includes a layered charged particle beam column package; a sample holder; and a layered differential pumping aperture that assists in maintaining two different vacuums.
1. A charged particle apparatus, comprising:
a layered charged particle beam column package having components for charged beam column operation;
a sample holder; and
a layered differential pumping aperture assembly integrated with the package and located between the sample holder and a charged particle source.
2. The apparatus of claim 1 , wherein the layers of the package are ceramic.
3. The apparatus of claim 2 , wherein the package layers are made of LTCC or HTCC.
4. The apparatus of claim 1 , further comprising additional apertures integrated with the package.
5. The apparatus of claim 4 , wherein the apertures are of different sizes.
6. The apparatus of claim 1 , wherein the assembly includes a two-stage or multi stage aperture in series.
7. The apparatus of claim 1 , wherein the assembly includes a metal insert.
8. The apparatus of claim 1 , wherein the aperture assembly is attached to the package.
9. The apparatus of claim 1 , further comprising a heater embedded in the column package configured to conductively heat the assembly.
10. The apparatus of claim 1 , further comprising electrical connections to a tube of the assembly configured such that current flows between the connections on the tube.
11. The apparatus of claim 1 , wherein the assembly includes a metalized tube.
12. The apparatus of claim 1 , wherein the assembly includes a hermetically sealed plug.
13. The apparatus of claim 11 , wherein the plug has a drilled aperture.
14. The apparatus of claim 1 , wherein the differential aperture assembly comprises silicon-on-insulator substrates comprising at least two electrically conductive silicon layers isolated by a buried oxide box layer.
15. A method, comprising:
generating a charged particle beam;
focusing the beam with a charged particle beam column onto a sample, the column having a layered charged particle beam column package with components for charged particle beam column operation; a sample holder holding the sample; and a layered differential pumping aperture assembly integrated with the package and located between a charged particle source and the sample holder;
maintaining a first vacuum at a region above the assembly at the charged particle source;
maintaining a second vacuum at a region below the assembly at the sample holder, the first vacuum being stronger than second vacuum;
scanning the beam over the sample; and
detecting charged particles from the sample.
16. The method of claim 15 , wherein the layers of the package are ceramic.
17. The method of claim 16 , wherein the package layers are made of LTCC or HTCC.
18. The method of claim 15 , further comprising conductively heating the assembly with a heater embedded in the package.
19. The method of claim 15 , further comprising running a current through a tube in the assembly to generate heat.
20. The method of claim 15 , wherein the assembly includes a metalized tube.
21. The method of claim 15 , wherein the assembly includes a metal insert.
22. The method of claim 15 , wherein the assembly includes a hermetically sealed plug.
23. The method of claim 15 , wherein the assembly includes a two-stage or multi-stage aperture in series configured to create a pressure differential inside the aperture assembly to minimize the flow of contamination from the sample to components.
24. The method of claim 23 , wherein the apertures are of different sizes.
25. The method of claim 15 , wherein the differential aperture assembly comprises silicon-on-insulator substrates comprising at least two electrically conductive silicon layers isolated by a buried oxide box layer.