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Tdb 05-84 P.6240 Improved Wiring Test Site Yield

IP.com Disclosure Number: IPCOM000042396D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kleinsasser, AW: AUTHOR

Abstract

Fabricating a superconducting integrated circuit device with a groundplane having a reduced critical temperature permits testing at a temperature where the circuitry under test is superconductive but the groundplane is resistive. This permits isolation of faults which might otherwise be masked by zero-resistance short circuits through the groundplane. At the present time, niobium-based technologies offer the greatest promise for the manufacture of a digital computer based on Josephson circuits. The package for such a technology is necessarily niobium based, and will involve a niobium groundplane as well as several levels of niobium wiring. The package must contain large amounts of wiring in order to provide for interconnections between the logic and memory chips and communication with the outside world.

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Tdb 05-84 P.6240 Improved Wiring Test Site Yield

Fabricating a superconducting integrated circuit device with a groundplane having a reduced critical temperature permits testing at a temperature where the circuitry under test is superconductive but the groundplane is resistive. This permits isolation of faults which might otherwise be masked by zero-resistance short circuits through the groundplane. At the present time, niobium-based technologies offer the greatest promise for the manufacture of a digital computer based on Josephson circuits. The package for such a technology is necessarily niobium based, and will involve a niobium groundplane as well as several levels of niobium wiring. The package must contain large amounts of wiring in order to provide for interconnections between the logic and memory chips and communication with the outside world. The measurement of the wiring yield and critical current is obviously a very important part of process development. Shorts between the wiring level of interest and the groundplane render a test site useless because a pair of shorts can mask a discontinuous section of wire. The large length of wiring necessary for a meaningful test site limits the number of test sites per wafer; the loss of information from even a few sites due to insulator failure is highly undesirable. The groundplane in the wiring test vehicle is intentionally fabricated with a groundplane having a reduced critical temperature. Testing is done as...