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Soft Metal Probe for Rapid Testing of Silicon Oxide Layers

IP.com Disclosure Number: IPCOM000079223D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Adley, JM: AUTHOR [+2]

Abstract

Conventional C-T and C-V testing of silicon oxide layers ordinarily requires the formation of aluminum contact dots on the layers. The dot formation introduces objectionable time lag between device processing and data collection. Test probing without requiring conductive contact dots is achieved by using a soft metal pressure contact probe, which assumes the same surface contour of the surface being tested to establish sound electrical contact.

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Soft Metal Probe for Rapid Testing of Silicon Oxide Layers

Conventional C-T and C-V testing of silicon oxide layers ordinarily requires the formation of aluminum contact dots on the layers. The dot formation introduces objectionable time lag between device processing and data collection. Test probing without requiring conductive contact dots is achieved by using a soft metal pressure contact probe, which assumes the same surface contour of the surface being tested to establish sound electrical contact.

As shown in the figure, a drop of solder 1 is formed on the end of solderable metal wire 2 and allowed to harden. Hardening may be done on a glass plate or similar flat surface 4 to produce a flat spot, if a large area probe is needed. The solder drop is next placed in gallium-indium alloy, such as 80% gallium 20% indium, for a short period of time allowing the gallium-indium to alloy in region 3 with the solder. A wire with the alloyed solder drop may now be placed in any probing station equipment and used for C-T or C-V testing (N material). The very soft lead-tin-gallium-indium alloy forms a metal dot of large area. The area depends on the shape of the solder drop, but remains constant for a given drop and for a given probe loading pressure. The present probe yields excellent C-T measurement results, producing an area (capacitance) equivalent to 30 mil aluminum dot.

Mercury may be substituted for the gallium and has been found to work equally well. This use of m...