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Tip and Probe Fabrication Method

IP.com Disclosure Number: IPCOM000034170D
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-26
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Smith, DA: AUTHOR [+2]

Abstract

A technique is described whereby tips and needle-shaped probes are fabricated with extremely sharp points. The concept provides for the reproducible fabrication of probes with controlled sharpness. It is an improvement over previous methods in that tips and probes are sharper and uniform and are reproducible with a controllable radii. Extremely sharp needle-shaped tips and probes, typically with a radius of less than 500 angstroms, are required in field ion microscopy (FIM), scanning tunneling microscopy (STM), electrical probe contacts for integrated circuits, and medical instrumentation applications. The concept described herein provides a method for fabricating extremely sharp needle-shaped tips and probes that have uniform and reproducible tips with a controllable radii.

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Tip and Probe Fabrication Method

A technique is described whereby tips and needle-shaped probes are fabricated with extremely sharp points. The concept provides for the reproducible fabrication of probes with controlled sharpness. It is an improvement over previous methods in that tips and probes are sharper and uniform and are reproducible with a controllable radii. Extremely sharp needle-shaped tips and probes, typically with a radius of less than 500 angstroms, are required in field ion microscopy (FIM), scanning tunneling microscopy (STM), electrical probe contacts for integrated circuits, and medical instrumentation applications. The concept described herein provides a method for fabricating extremely sharp needle-shaped tips and probes that have uniform and reproducible tips with a controllable radii. Fine wire 10, as shown in the figure, typically ten to twenty mils in diameter, fastened to aluminum holder 11 and upper tip holder/electrode contact 12, is suspended in electro-polishing solution 13. Aluminum holder 14 fastened to the bottom end of fine wire 10 is positioned inside hollow cylinder sleeve guide 17. Low voltage is applied to fine wire 10 and counter electrode 15, so that current flows on the order of 50 to 500 ma. Either a one- or two-layer system may be used. In a one-layer system, the tip is formed at the interface of electro-polishing solution 13 and its surface. In a two-layer system, formation of the tip occurs inside a thin, approximately 2 mm, floating second layer of solution. The bottom layer, dense non-electrolyte 16, is usually carbon tetrochloride. When the specimen necks down and brea...