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High-Speed Chip Carrier Connections (Two-Wire Bonds)

IP.com Disclosure Number: IPCOM000101073D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 30K

Publishing Venue

IBM

Related People

Miersch, EF: AUTHOR

Abstract

To eliminate the high series inductance of a single wire connecting a semiconductor chip 1 to circuit lines on a multilayer substrate 2, every signal wire 3 is complemented by another wire 4 connected to ground plane 5 of multilayer substrate 2. Ground wire 4 is glued to the signal wire (Figs. 1 and 2) by, e.g. polyimide 6, so that the wire pair represents a primitive transmission line with a defined characteristic impedance. The return current of the signals is kept as close as possible to the signal currents, minimizing the self-inductance of the current conducting loop and increasing the mutual inductance of signal wire 3 and return path 4. Magnetic coupling field H is closely adjacent to the individual signal wires 3. High magnetic field densities exist only in the vicinity of signal wires 3.

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High-Speed Chip Carrier Connections (Two-Wire Bonds)

       To eliminate the high series inductance of a single wire
connecting a semiconductor chip 1 to circuit lines on a multilayer
substrate 2, every signal wire 3 is complemented by another wire 4
connected to ground plane 5 of multilayer substrate 2.  Ground wire 4
is glued to the signal wire (Figs. 1 and 2) by, e.g. polyimide 6, so
that the wire pair represents a primitive transmission line with a
defined characteristic impedance.  The return current of the signals
is kept as close as possible to the signal currents, minimizing the
self-inductance of the current conducting loop and increasing the
mutual inductance of signal wire 3 and return path 4.  Magnetic
coupling field H is closely adjacent to the individual signal wires
3.  High magnetic field densities exist only in the vicinity of
signal wires 3.  This reduces the mutual inductance of those wires
and, thus, the mutually generated noise.  Each signal wire 3 and its
associated ground wire 4 may be coated (6).  The reduced noise can be
directly transformed into increased circuit speed.