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Low Inductance Josephson Contact Array

IP.com Disclosure Number: IPCOM000049988D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Bickford, HR: AUTHOR

Abstract

High density Josephson circuit chips have to be tested using contact arrays which have low inductance and high density. This testing must be at switching speeds on the order of 10-20 picoseconds. One such technique for doing this type of testing is shown in the IBM Technical Disclosure Bulletin 23, 4363-4364 (February 1981). However, in order to provide easy minimization in size of the contact array in order to reduce mutual inductance to an amount which would also minimize crosstalk for 10-20-picosecond rise-time signals, the present technique is preferred.

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Low Inductance Josephson Contact Array

High density Josephson circuit chips have to be tested using contact arrays which have low inductance and high density. This testing must be at switching speeds on the order of 10-20 picoseconds. One such technique for doing this type of testing is shown in the IBM Technical Disclosure Bulletin 23, 4363-4364 (February 1981). However, in order to provide easy minimization in size of the contact array in order to reduce mutual inductance to an amount which would also minimize crosstalk for 10-20-picosecond rise-time signals, the present technique is preferred.

The contact array includes a plurality of pins 10A, 10B and 10C which are used to provide electrical contact between a space transformer 12 and a Josephson circuit chip 14. Pins 10A, 10B and 10C are blunt-ended platinum pins which make contact at their ends to solder pads 16A, 16B and 16C on the chip 14, and to solder pads 18A, 18B and 18C at the space transformer 12. This contact array is completely demountable, captivated contacts relying at both ends on penetration of the contact pins 10A, 10B and 10C into solder pads, and on the perpendicular force of the solder on the side of the contact pins due to differential shrinkage.

The contact pin array is assembled in a silicon frame that is made by bonding two pieces of silicon 20A and 20B which have been electro-discharge machined to obtain the required hole profile for the pins, and have been subsequently passivated.

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