Browse Prior Art Database

Lead Modification for Solderless Attachment of Flatpack Components

IP.com Disclosure Number: IPCOM000103323D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 37K

Publishing Venue

IBM

Related People

Chalco, P: AUTHOR [+2]

Abstract

One key problem in attempting single-point solderless thermocompression bonding of leads to FR-4 cards is overheating caused by the relatively large masses of the leads to be bounded sequentially. Another major problem is the high rigidity of the thick leads which transmits readily high stresses to the joint exposing the lead attachment to fatigue failures.

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Lead Modification for Solderless Attachment of Flatpack Components

      One key problem in attempting single-point solderless
thermocompression bonding of leads to FR-4 cards is overheating
caused by the relatively large masses of the leads to be bounded
sequentially.  Another major problem is the high rigidity of the
thick leads which transmits readily high stresses to the joint
exposing the lead attachment to fatigue failures.

      A solution to these problems consists of flattening the ends of
the leads to reduce their mass as shown in the Figure.  It is
desirable to reduce the thickness of the leads to about 1 to 2 mils
and the width to 6 to 10 mils. This reshaping operation can be
achieved by several means such as mechanical impact followed by
trimming, chemical or electrochemical machining, or
electrostatic-discharge machining.  For existing components the leads
can be modified in a tool designed to flatten and trim the leads to
any desired size and shape.  However, for components to be built, the
forming process of the leadframe can be modified to provide the
desired reduced-mass features of the leads.

      Disclosed anonymously.