Authored By:
Phil Isaacs and Sven Peng
IBM Corporation
Rochester, MN, USA, and Shenzen, China
Seow Wah Sng, Wai Mun Lee, and Alex Chen
Celestica
Song Shan Lake, China, and Toronto, Canada
Summary
The advancement in performance of motherboard-daughter-card interconnects has been significantly increasing for several years. Due to the constraint of board surface real estate, the increase is seen in the higher I/O counts and the decrease in the signal integrity acceptance window. Through this evolution there has been a migration to ever more complex surface mount connectors. The complexity factor creates new challenges in assembly and rework of these connectors. The difficulty manifests itself through a number of factors; the increase in connector body size, the increase in mass, a significant increase in the number of contacts, or leads, the increase in lead density, the number of rows of leads which are now hidden by the connector housing from inspection or from touch-up all make the assembly and rework of the connector much more challenging. The use of advanced vapor phase reflow equipment is a key element to the success of this process. This paper discusses how to assemble this type of connector, how to rework the connectors and how to assure compliance to all connector requirements without sacrificing solder joint reliability and performance.
Initially Published in the SMTA Proceedings
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