Chuck with triaxial construction
View Patent ↗A chuck with triaxial construction comprises a receiving surface for a test substrate and arranged below the receiving surface: an electrically conductive first surface element, an electrically conductive second surface element electrically insulated therefrom, and an electrically conductive third surface element electrically insulated therefrom, and, between the first and the second surface element, a first insulation element and, between the second and the third surface element, a second insulation element. A chuck for very low current measurements which can be used to prevent the occurrence of leakage currents and a triboelectric charge and which is configured favourably in terms of production, is achieved because at least one of the electrically conductive surface elements is mechanically connected to at least one insulation element and has an elasticity that compensates for an expansion difference resulting from differences in different coefficients of expansion between a respective surface element and an adjoining insulation element.
1. A chuck with triaxial construction, the chuck comprising:
a receiving surface that is configured to receive a test substrate;
a first surface element, wherein the first surface element is electrically conductive;
a second surface element, wherein the second surface element is electrically conductive and is separated from the receiving surface by the first surface element;
a third surface element, wherein the third surface element is electrically conductive and is separated from the first surface element by the second surface element;
a first insulation element, wherein the first insulation element is located between and electrically isolates the first surface element and the second surface element;
a second insulation element, wherein at least one of the surface elements is held in contact with at least one insulation element by vacuum and has an elasticity that compensates for an expansion difference resulting from differences in different coefficients of thermal expansion between a respective surface element and an adjoining insulation element; and
an electrically insulating baseplate that includes the second insulation element, wherein the electrically insulating baseplate includes a vacuum clamping opening that is configured to be connected to a vacuum source, wherein the third surface element is included in the baseplate, and further wherein the second surface element is placed onto a top side of the baseplate and is configured to be fixed to the baseplate by a vacuum that is applied to the vacuum clamping opening.
2. Chuck according to claim 1 , wherein at least one of the first surface element, the second surface element, and the third surface element comprises a film.
3. Chuck according to claim 2 , wherein the film has a thickness of 5 to 10 μm.
4. Chuck according to claim 1 , wherein the second surface element is provided with a plurality of through openings, wherein the first insulation element is composed of a porous insulation material, and further wherein the second surface element is located on a top side of the second insulation element and configured to be fixed within the chuck by the vacuum.
5. Chuck according to claim 4 , wherein the second surface element comprises a perforated film.
6. Chuck according to claim 1 , wherein at least one of the first, insulation element and the second insulation element comprises a ceramic.
7. Chuck according to claim 6 , wherein the ceramic comprises boron nitride.
8. Chuck according to claim 1 , further comprising an electrically insulating baseplate that includes a vacuum clamping opening that is configured to be connected to a vacuum source, wherein the third surface element is located on a top side of the baseplate and is configured to be fixed to the baseplate by a vacuum that is applied to the vacuum clamping opening.
9. Chuck according to claim 8 , wherein the third surface element is provided with a first plurality of through openings, wherein the second insulation element is composed of a first porous insulation material, and further wherein the second surface element is located on a top side of the second insulation element and configured to be fixed within the chuck by the vacuum.
10. Chuck according to claim 9 , wherein the second surface element is provided with a second plurality of through openings, wherein the first insulation element is composed of a second porous insulation material, and further wherein the first surface element is located on a top surface of the first insulation element and configured to be fixed within the chuck by the vacuum.
11. Chuck according to claim 10 , wherein at least one of the third surface element and the second surface element comprises a perforated film.
12. Chuck according to claim 8 , wherein the baseplate is formed as an independent thermochuck.
13. Chuck according to claim 1 , wherein an exposed surface of the first surface element defines the receiving surface.
14. Chuck according to claim 1 , wherein a top side of the first surface element is provided with a metal plate, and further wherein a top side of the metal plate defines the receiving surface.
15. Chuck according to claim 14 , wherein the metal plate includes a first vacuum clamping opening that is configured to affix the test substrate to the metal plate when a vacuum is applied thereto, and further wherein the metal plate includes a second vacuum clamping opening that is configured to affix the metal plate to the first surface element when a vacuum is applied thereto.
16. Chuck according to claim 14 , wherein the first surface element is provided with a plurality of through openings.