Charged particle blocking element, exposure apparatus comprising such an element, and method for using such an exposure apparatus
The invention relates to an exposure apparatus and a method for projecting a charged particle beam onto a target. The exposure apparatus comprises a charged particle optical arrangement comprising a charged particle source for generating a charged particle beam and a charged particle blocking element and/or a current limiting element for blocking at least a part of a charged particle beam from a charged particle source. The charged particle blocking element and the current limiting element comprise a substantially flat substrate provided with an absorbing layer comprising Boron, Carbon or Beryllium. The substrate further preferably comprises one or more apertures for transmitting charged particles. The absorbing layer is arranged spaced apart from the at least one aperture.
1. A charged particle blocking element, comprising:
a substrate comprising an aperture allowing passage of at least a part of a charged particle beam from a charged particle source; and
an absorbing layer configured to absorb at least a part of the charged particle beam from the charged particle source,
wherein the absorbing layer is provided on a surface of the substrate,
wherein the absorbing layer of a material comprises Carbon, Boron (B), or Beryllium (Be), and
wherein at least a part of the substrate comprises an electrically conductive material configured to remove absorbed electrical charges from the absorbing layer.
2. The charged particle blocking element according to claim 1 , wherein the absorbing layer is arranged spaced apart from an edge of the aperture to prevent the part of the charged particle beam passing through the aperture from being disrupted.
3. The charged particle blocking element according to claim 1 , wherein the absorbing layer has a thickness sufficient to prevent backscattering of the charged particles from a portion of the substrate located below the absorbing layer and thin enough for electrical charge of the charged particles to be received by the substrate.
4. The charged particle blocking element according to claim 1 , wherein the substrate comprises a connecting part for connecting the substrate to a voltage supply or to ground potential.
5. The charged particle blocking element according to claim 1 , wherein the absorbing layer is a coating of Boron, Boron Nitride, or Silicon Carbide.
6. The charged particle blocking element according to claim 1 , further comprising a cooling conduit for cooling the absorbing layer or the substrate.
7. The charged particle blocking element according to claim 1 , wherein the aperture comprises a plurality of apertures arranged to form one or more aperture arrays, each aperture array arranged in a corresponding array area of the substrate.
8. The charged particle blocking element according to claim 7 , wherein the absorbing layer at least partially extends in the array area of the substrate.
9. A charged particle blocking element, comprising:
a substrate comprising an aperture allowing passage of at least a part of a charged particle beam from a charged particle source;
an absorbing layer configured to absorb at least a part of the charged particle beam from the charged particle source; and
an electrically conductive layer at least partially arranged in between the substrate and the absorbing layer, the electrically conductive layer configured to remove absorbed electrical charges from the absorbing layer,
wherein the absorbing layer is at least partially provided on a surface of the substrate, and
wherein the absorbing layer of a material comprises Carbon, Boron (B), or Beryllium (Be).
10. The charged particle blocking element according to claim 9 , wherein the absorbing layer is arranged spaced apart from an edge of the aperture to prevent the part of the charged particle beam passing through the aperture from being disrupted.
11. The charged particle blocking element according to claim 9 , wherein the absorbing layer has a thickness sufficient to prevent backscattering of the charged particles from a portion of the substrate located below the absorbing layer and thin enough for electrical charge of the charged particles to be received by the substrate.
12. The charged particle blocking element according to claim 9 , wherein the electrically conductive layer is electrically connected to a voltage supply or to ground potential.
13. The charged particle blocking element according to claim 9 , wherein the absorbing layer is a coating of Boron, Boron Nitride, or Silicon Carbide.
14. The charged particle blocking element according to claim 9 , wherein the electrically conductive layer comprises Molybdenum (Mo) or Chromium (Cr).
15. The charged particle blocking element according to claim 9 , further comprising a cooling conduit for cooling the absorbing layer, the substrate, or the electrically conductive layer.
16. The charged particle blocking element according to claim 15 , further comprising a thermally conductive layer configured to provide a heat conducting path from the absorbing layer to the cooling conduit.
17. The charged particle blocking element according to claim 9 , wherein the aperture comprises a plurality of apertures arranged to form one or more aperture arrays, each aperture array arranged in a corresponding array area of the substrate.
18. The charged particle blocking element according to claim 17 , wherein the absorbing layer at least partially extends in the array area of the substrate.
19. A charged particle beam exposure apparatus, comprising:
a charged particle optical arrangement for forming a charged particle beam and projecting at least a part of the charged particle beam onto a target, comprising:
a charged particle source for generating the charged particle beam; and
a charged particle blocking element comprising:
a substrate comprising an aperture allowing passage of at least a part of a charged particle beam from a charged particle source; and
an absorbing layer configured to absorb at least a part of the charged particle beam from the charged particle source,
wherein the absorbing layer is provided on a surface of the substrate and arranged spaced apart from an edge of the aperture to prevent the part of the charged particle beam passing through the aperture from being disrupted,
wherein the absorbing layer of a material comprises Carbon, Boron (B), or Beryllium (Be), and
wherein at least a part of the substrate comprises an electrically conductive material configured to remove absorbed electrical charges from the absorbing layer.
20. The charged particle beam exposure apparatus according to claim 19 , wherein the aperture of the charged particle blocking element comprises a plurality of apertures arranged to form one or more aperture arrays, each aperture array arranged in a corresponding array area of the substrate of the charged particle blocking element.