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Browse Prior Art Database

Multi-Chip Module With Improved Engineering Change Rework Capability

IP.com Disclosure Number: IPCOM000100112D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 51K

Publishing Venue

IBM

Related People

Klink, E: AUTHOR [+3]

Abstract

In an exemplary embodiment, a multi-chip module (MCM) may have four chip locations. Each chip may have as many as 324 signal I/O pads. The module has 385 module signal pins. On the module substrate, there are chip pad/chip pad and chip pad/module pin connections.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 61% of the total text.

Multi-Chip Module With Improved Engineering Change Rework Capability

       In an exemplary embodiment, a multi-chip module (MCM) may
have four chip locations.  Each chip may have as many as 324 signal
I/O pads.  The module has 385 module signal pins.  On the module
substrate, there are chip pad/chip pad and chip pad/module pin
connections.

      Each chip I/O line is led across engineering change (EC) pads
which permit wiring changes on the module with soldered chips.
Connections may be interrupted by laser beam or be produced from thin
gold wires (wire bonding).  An EC module of this kind is used in the
test (bring-up) phase of a system.

      Non-used chip signal pads are led across the EC pad only up to
the end of the redistribution plane of the MCM substrate.  Non-used
module pins are not connected to the chip plane and thus are not
available for ECs from the chip pad to the circuit board.

      The MCM has two module EC pins for each chip location. These
are special connections between two module pins and two EC pads
especially provided for this purpose on the module substrate surface.

      If additional module pins are required, there are only two EC
pins per chip, which is insufficient.

      To improve the rework capability, it is proposed to provide
connections between unused module pins and unused chip pads.

      In one conceivable embodiment the module substrate is wired by
EDS (electronic design system).  The chip prot...