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Metal Insulator Semiconductor Probe

IP.com Disclosure Number: IPCOM000078287D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Tietjen, PA: AUTHOR

Abstract

The figure shows a tool for making an immediate and intimate contact at room temperature with, for example, an insulating layer on a silicon wafer.

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Metal Insulator Semiconductor Probe

The figure shows a tool for making an immediate and intimate contact at room temperature with, for example, an insulating layer on a silicon wafer.

In the evaluation of the properties of insulating layers on silicon surfaces, it is often necessary to make intimate, clean electrical contact with the insulator. Then, the capacitance formed between the contact and the silicon wafer can be used to investigate impurities in the insulator, and at the silicon/insulator interface.

A tool for making such a contact comprises a probe 1 of hard material which does not react with indium at room temperature, e.g. stainless steel. The probe has a central hole 2 formed throughout its length. At the top of the probe the hole has a portion 3 of larger diameter, which accommodates an extrusion screw 4 and contains indium 5 of high purity. The lower face of the probe is of relatively small area compared with the overall cross-sectional area of the probe. The probe is mounted on two supporting columns 6 and is downwardly biased by the springs 7. Below the lower face of the probe is an electrical contact pad 8. which is gold or gold-plated to ensure good electrical contact with a silicon wafer placed upon it. The contact pad may be a vacuum chuck. Beneath the contact pad is a slab of insulator 9 to prevent shorting between the pad 8 and the stand.

In operation, the probe 1 is raised and a wafer 10 is placed on the pad 8 with its insulating surface u...