New Methods for Mechanical Mating Characterization of Surface Mount Technology Card to Board Interconnections

Large scale system packaging density requirements continue to place increased demand on improving card to board interconnections in the areas of electrical performance as well as physical density. To address these needs, card to board assemblies with new high density, surface mount technology (SMT) waferized interconnect systems have been developed, along with new methods to assess their mating characteristics to ensure both sufficient initial mating as well as long-term connection reliability. Applying existing measurement devices, new methodologies are presented to record interconnection alignment and the stress in solder connections. Exploiting the physical construction of the interconnection system, analytical and experimental techniques are detailed to reveal how solder attach strength and connector mating strains can be coupled to predict SMT solder strains during the mating cycle as well as during package environmental stress testing.