Browse Prior Art Database

New Transistor and Schottky Diode Chain Test Structure

IP.com Disclosure Number: IPCOM000040607D
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Magdo, S: AUTHOR [+2]

Abstract

This is a method of forward biasing in test site chain structures of semiconductor devices. By forward biasing, it is possible to function without wiring the separate collector contacts. This improves the design density of the system. Transistors and Schottky barrier diode (SBD) chains are used to monitor masterslice defects such as emitter-to-collector shorts or leakages, base-to-collector shorts or leakages, and Schottky diode shorts and leakages. In the figure the chains 1 are wired in parallel 2. It is not possible to separate metal shorts between these parallel wires from masterslice defects. A short between the emitter and collector wire, for instance, shows up as a pipe. Here a new chain structure eliminates the metal short interference.

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New Transistor and Schottky Diode Chain Test Structure

This is a method of forward biasing in test site chain structures of semiconductor devices. By forward biasing, it is possible to function without wiring the separate collector contacts. This improves the design density of the system. Transistors and Schottky barrier diode (SBD) chains are used to monitor masterslice defects such as emitter-to-collector shorts or leakages, base-to- collector shorts or leakages, and Schottky diode shorts and leakages. In the figure the chains 1 are wired in parallel 2. It is not possible to separate metal shorts between these parallel wires from masterslice defects. A short between the emitter and collector wire, for instance, shows up as a pipe. Here a new chain structure eliminates the metal short interference. The collector 3 is contacted with a remotely located substrate contact 4 through the forward-biased collector isolation junction. The remoteness of the contact serves to eliminate shorts. Collector wiring may thus be omitted from the chain while keeping the the collector contacts so as to preserve the product's personality. Emitter 5 and base 6 wire shorts do not interfere since the emitter-base junction is zero-biased during the emitter-to-collector leakage test. The principle applies to Schottky diode chains where the cathodes can be contacted through the substrate.

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