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Wide Bandwidth, Low Crosstalk Connections to Chips Containing Cryogenic Circuitry

IP.com Disclosure Number: IPCOM000081711D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Warren, RS: AUTHOR

Abstract

Ultrahigh speed Josephson junction circuitry requires wide bandwidth chip-to-chip interconnections as well as chip-to-input and output cables. Such connections must be capable of a bandwidth greater than 10 GH(z) and be able to carry pulses of up to 50 mA with rise times less than a1 ns, without inducing crosstalk in neighboring lines which is greater than a few tens of microvolts. Finally, a high contact density must be permitted along with a simple approach for mounting and dismounting the chips.

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Wide Bandwidth, Low Crosstalk Connections to Chips Containing Cryogenic Circuitry

Ultrahigh speed Josephson junction circuitry requires wide bandwidth chip- to-chip interconnections as well as chip-to-input and output cables. Such connections must be capable of a bandwidth greater than 10 GH(z) and be able to carry pulses of up to 50 mA with rise times less than a1 ns, without inducing crosstalk in neighboring lines which is greater than a few tens of microvolts. Finally, a high contact density must be permitted along with a simple approach for mounting and dismounting the chips.

Fig. 1 shows an arrangement which fulfills all the above requirements.

With respect to chip-to-chip connections strip lines I which are insulated from a floating ground plane, are laid out or arranged to mate with contact pads 3 disposed on the edge of chips 4 as shown in Fig. 2, to interconnect with other circuit chips 4. Thus, in Fig. 1, chips 4 are positioned over apertures 5 in substrate 2 in such a way that the contact pads 3 mate with strip lines 1, which are formed on the surface of circuit connection pad 2. The latter may be formed from copper-clad MYLAR* one side of which carries strip lines 1 which are formed by well-known photolithographic and etching techniques, while the unetched back side forms a floating ground plane for strip lines 1.

To insure contact between the ends of strip lines 1 and contact pads 3, a soft metal such as indium is applied locally to strip lines 1 and to pads 3 to a thickness sufficient for good contact. The soft metal covering the contact area is then pressed with an optically flat tool to a...