Browse Prior Art Database

I/O Pin Attach/ Repair with Polymer Metal Composite Paste (PMC)

IP.com Disclosure Number: IPCOM000109141D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 1 page(s) / 70K

Publishing Venue

IBM

Related People

Booth, R: AUTHOR [+7]

Abstract

Disclosed is a method of attaching pins to an electronic substrate with a conductive adhesive material. The conductive adhesive consists of a soluble thermoplastic material loaded with metal particles such as silver or gold which is formulated into a screenable paste. Since the thermoplastic material is both soluble and ablatable with excimer laser, attached pins may be removed and repaired.

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I/O Pin Attach/ Repair with Polymer Metal Composite Paste (PMC)

      Disclosed is a method of attaching pins to an electronic
substrate with a conductive adhesive material.  The conductive
adhesive consists of a soluble thermoplastic material loaded with
metal particles such as silver or gold which is formulated into a
screenable paste.  Since the thermoplastic material is both soluble
and ablatable with excimer laser, attached pins may be removed and
repaired.

      The conductive adhesive pin attachment process has several
advantages compared to traditional soldering or brazing.  It is a
fluxless process which is contamination insensitive.  The attachment
process uses low modulus, low temperature materials resulting in
little thermal stress on the joint and substrate during bonding.
Lastly, the materials are not susceptible to atmospheric moisture and
corrosion as are Pb-Sn and Pb-In.

      A cross-section of the pin attachment procedure is shown in
Figure 1.  Conductive adhesive material may be screened onto the pin
or the substrate or onto both surfaces.  The pin is encapsulated for
mechanical reinforcement with a polymer films(s) consisting of
thermoplastic materials, glass or ceramic reinforced thermoplastic
materials, or high Tg materials with a thermoplastic adhesive
coating.  Reinforcing and encapsulating polymers may be similar
materials or may be individually selected for desired properties as
shown in the Figure.  The encapsulation and rei...