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Method for a serrated pin structure for wave soldered heatsink pins

IP.com Disclosure Number: IPCOM000010060D
Publication Date: 2002-Oct-16
Document File: 2 page(s) / 81K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a serrated pin structure for wave soldered heatsink pins. Benefits include improved reliability.

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Method for a serrated pin structure for wave soldered heatsink pins

Disclosed is a method for a serrated pin structure for wave soldered heatsink pins. Benefits include improved reliability.

Background

        � � � � � Weak mechanical strength causes reliability failures due to an electrical open for wave soldered heatsink pins. Cracks, which are detected post-assembly, initiate from the primary side of the pins at eutectic Sn-Pb solder to Cu-Sn intermetallic compound (IMC) interface. Propagation occurs along this interface at a relatively fast rate compared to other through-hole mount (THM) connectors or e-caps, due to the large heatsink structure. The conventional smooth pin structure does not present an obstruction to deter crack propagation (see Figure 1).

� � � � � Conventionally, careful handling of the wave solder heatsink minimizes mechanical bending due to compression stress, but this requires increased operator training.

Description

        � � � � � The disclosed method is a serrated heatsink pin structure that enhances mechanical strength (see Figure 2). The key elements of the method include:

•        � � � � A serrated pin structure for the wave soldered heatsink pins

•        � � � � An interlocking effect between the solder and IMC layer that prohibits mechanical cracking due to bending or compression stress

� � � � � The pin temperature (from 70oC to ~120oC) during the wave process enhances wetting of the pin coating layer when wave soldered, producing a homogenous eutectic Pb-Sn mi...