Thermal optical chuck
View Patent ↗An accessible optical path to a lower surface of a heatable device under test is provided by a thermal optical chuck comprising a transparent resistor deposited on transparent plate arranged to supporting the device in a probe station.
1. A thermal optical chuck for supporting a device under test in a probe station, said thermal optical chuck comprising:
(a) a transparent plate having an edge, a first surface for supporting said device under test, and an opposing second surface;
(b) a transparent conductor having a resistance, said transparent conductor being deposited over an area of at least one of said first and said second surfaces of said transparent plate;
(c) a first bus bar in conductive contact with said transparent conductor, said first bus bar being connectible to a source of electric current; and
(d) a second bus bar in conductive contact with said transparent conductor, said second bus bar being connectible to said source of electric current and spaced apart from said first bus bar.
2. The thermal optical chuck of claim 1 wherein said transparent conductor comprises indium tin oxide.
3. The thermal optical chuck of claim 1 wherein said transparent conductor comprises silver zinc oxide.
4. The thermal optical chuck of claim 1 wherein said transparent conductor comprises antimony tin oxide.
5. The thermal optical chuck of claim 1 wherein said transparent conductor comprises a conductive polymer.
6. The thermal optical chuck of claim 5 wherein said conductive polymer comprises poly(ethylenedioxythiophene).
7. The thermal optical chuck of claim 5 wherein said conductive polymer comprises polyaniline.
8. The thermal optical chuck of claim 1 wherein said transparent plate comprises glass.
9. The thermal optical chuck of claim 1 wherein said transparent plate comprises fused silica.
10. The thermal optical chuck of claim 1 wherein said transparent plate comprises quartz.
11. The thermal optical chuck of claim 1 wherein said transparent plate comprises sapphire.
12. The thermal optical chuck of claim 1 wherein said transparent plate comprises lithium niobate.
13. The thermal optical chuck of claim 1 wherein said area comprises a rectangle.
14. The thermal optical chuck of claim 1 wherein said area comprises a square.
15. The thermal optical chuck of claim 1 wherein said second bus bar includes a length arranged substantially parallel to a portion of said first bus bar.
16. The thermal optical chuck of claim 1 further comprising:
(a) a base; and
(b) a support maintaining said base and said transparent plate in a spaced relationship.
17. The thermal optical chuck of claim 1 further comprising:
(a) a frame adjacent to said edge of said transparent plate, said frame including a surface having portions defining an aperture, said aperture being connectible to a vacuum source; and
(b) a clamp including a first surface arranged to engage an upper surface of a device under test supported by said transparent plate and a second surface arranged to block a flow of air to said aperture when said first surface is engaged with said upper surface of said device under test and said aperture is connected to a vacuum source.