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Method of Fabricating Metal Substrates with Feed-Through Pins by CVD Techniques

IP.com Disclosure Number: IPCOM000103510D
Original Publication Date: 1990-Dec-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 1 page(s) / 64K

Publishing Venue

IBM

Related People

Grebe, KR: AUTHOR [+3]

Abstract

In packaging high-speed large-scale integration (LSI) silicon chips, the use of a metal substrate as the chip carrier is advantageous because it serves as the ground plane for the signal and power supply. It also conducts heat out from the chip and, for molybdenum and tungsten, matches the thermal expansion coefficient of silicon and, therefore, reduces the fatigue of solder joints.

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Method of Fabricating Metal Substrates with Feed-Through Pins by CVD Techniques

      In packaging high-speed large-scale integration (LSI) silicon
chips, the use of a metal substrate as the chip carrier is
advantageous because it serves as the ground plane for the signal and
power supply.  It also conducts heat out from the chip and, for
molybdenum and tungsten, matches the thermal expansion coefficient of
silicon and, therefore, reduces the fatigue of solder joints.

      In certain situations, the requirements for the metal substrate
are such that there must be a matrix of high density of pins for both
signal (N 10 mils on 50-mil centers) and power (N 20 mils on 50-mil
centers) going through the substrate and electrically insulated from
it (see figure).  The dielectric isolation layer for the signal pins
should be thick for (5-mil) small capacitive loading (1-2 pf).  The
dielectric layer for the power pins should be thin (1-2) microns) for
small package inductances .01 nh).

      In order to meet all the above requirements and to be able to
batch fabricate, the following method is used:
      (1)  Precoat molybdenum or tungsten wires with dielectric
layers and cut into proper length (100-200 mils) to make discrete
signal and power pins.  For signal pins the wire can be coated by
using glass tubing and reflowing or by pulling the wire through a
solution containing suspended glass or ceramic particles and then
curing.  For power pins, the isolation...