Patent ID: 9506973
Filing Date: 2016-11-29
CPC Classification: G01R,H01L,Y10T

Claim Text:
1. A chuck comprising: (a) an upper conductive layer having a lower surface and an upper surface suitable to contact and support a device under test; (b) an upper insulating layer having an upper surface at least in partial face-to-face contact with said lower surface of said upper conductive layer, and a lower surface, wherein the upper insulating layer is horizontally distinct from the upper conductive layer; and (c) a middle conductive layer having an upper surface at least in partial face-to-face contact with said lower surface of said upper insulating layer, and a lower surface, wherein the middle conductive layer is horizontally distinct from the upper insulating layer; wherein the chuck is an assembly of separate parts, wherein the separate parts include the upper conductive layer, the upper insulating layer, and the middle conductive layer; wherein the upper conductive layer includes a conductive layer vacuum path configured to apply a vacuum to the lower surface of the upper conductive layer to retain the lower surface of the upper conductive layer in at least partial face-to-face contact with the upper surface of the upper insulating layer; wherein the upper insulating layer includes an insulating layer vacuum path configured to apply a vacuum to the lower surface of the upper insulating layer to retain the lower surface of the upper insulating layer in at least partial face-to-face contact with the upper surface of the middle conductive layer; and further wherein no vacuum path extends between the upper surface of the upper insulating layer and the lower surface of the upper insulating layer.