Mercury probe
AssigneeMSI Electronics Inc.
InventorJohn H. Greig
Life of this patent
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Abstract
The disclosed apparatus provides a mercury electrode for making non-destructive tests, especially for Schottky-diode tests of semi-conductors such as silicon. By developing vacuum under a test wafer on a support, a column of mercury is drawn into contact with the test wafer through a bore in the support that accurately establishes the area of the contact. The vacuum system also holds the test wafer securely in position, it avoids spillage of mercury, and additional circuit-completing contact can be made to the wafer with independently controlled pressure.
Claims11
Electrical test apparatus, including means for supporting a test wafer at the face thereof to be tested, the supporting means providing a wafer-engaging face, a reservoir of mercury below said supporting means, means providing a passage from the reservoir through at least part of said supporting means to the wafer-engaging face thereof for enabling the mercury to contact said test face of the wafer, said passage means terminating in an aperture in said wafer-engaging face accurately determining an area of contact of the mercury to a wafer on said wafer-engaging face, said supporting means providing electrical insulation between the wafer and the mercury that contacts the wafer during use of the apparatus except for said determined contact area, means for developing a vacuum in the interface between the wafer-engaging face of said supporting means and the wafer near and at said aperture for drawing mercury from the reservoir to said contact area and for holding the wafer against said wafer-engaging face.
Electrical test apparatus including a support, an orifice plate on the support, said orifice plate having a flat surface for supporting a flat test wafer, said support and said orifice plate having aligned bores extending to an aperture in said flat surface, means for developing vacuum at the flat surface of the orifice plate at and near said aperture but only when a test wafer is disposed thereon for elevating mercury through said aligned bores to said aperture to form an electrode engaging a wafer on the orifice plate, said orifice plate being separably received on the support for providing a desired electrode area in the orifice plate.
Dependencies are inferred from the claim text.