Browse Prior Art Database

Structure for Package Interconnection

IP.com Disclosure Number: IPCOM000109465D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 1 page(s) / 60K

Publishing Venue

IBM

Related People

Horton, RR: AUTHOR [+6]

Abstract

It is desirable to be able to make reworkable package interconnections by soldering conducting leads or cable ends to a package or semiconductor substrate. The solder-joint structure, described here, solves the problem of vertical spatial control for joining of metal conductors to substrates by means of soldering.

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This is the abbreviated version, containing approximately 94% of the total text.

Structure for Package Interconnection

      It is desirable to be able to make reworkable package
interconnections by soldering conducting leads or cable ends to a
package or semiconductor substrate.  The solder-joint structure,
described here, solves the problem of vertical spatial control for
joining of metal conductors to substrates by means of soldering.

      The problem encountered with making a solder reflow bond to a
conducting lead is that the liquid solder does not support the lead
above the substrate surface.  It is necessary to do this to keep the
lead from damaging or shorting to the substrate during the attach
procedure or in subsequent stress during operation of the system.  It
is also necessary to maintain vertical spatial control where many
leads make up a multiconductor interconnection.

      The solution to the problem is to produce a solder joint
structure as shown in the figure.  The conducting lead has been made
to have a built-in standoff at the terminating end, shown as a sphere
in the figure.  The terminal end of the lead serves as a standoff to
keep the lead or an array of leads at a fixed height above the
surface of the substrate.  The termination becomes the center of the
solder bond, providing a large area of solder-tometal joining
surface.

      Solder is applied to the joint by any of several means; wave
soldering, solder dipping, solder evaporation, or solder paste
application etc., and subsequently the joint is forme...