An Adaptive Interpolator Algorithm For Area-Array Fine Guidance Sensors

1984 ◽  
Author(s):  
Thomas A. Glavich
Keyword(s):  
Area Array ◽  
Adaptive Interpolator

Case Studies of Brittle Interfacial Failures in Area Array Solder Interconnects

2000 ◽  
Author(s):  
George M. Wenger ◽  
Richard J. Coyle ◽  
Patrick P. Solan ◽  
John K. Dorey ◽  
Courtney V. Dodd ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Case Studies ◽  
Failure Modes ◽  
Electroless Nickel ◽  
Electrical Performance ◽  
Printed Wiring Board ◽  
Solder Interconnects ◽  
Area Array ◽  
Surface Finishes ◽  
Soldering Reaction

Abstract A common pad finish on area array (BGA or CSP) packages and printed wiring board (PWB) substrates is Ni/Au, using either electrolytic or electroless deposition processes. Although both Ni/Au processes provide flat, solderable surface finishes, there are an increasing number of applications of the electroless nickel/immersion gold (ENi/IAu) surface finish in response to requirements for increased density and electrical performance. This increasing usage continues despite mounting evidence that Ni/Au causes or contributes to catastrophic, brittle, interfacial solder joint fractures. These brittle, interfacial fractures occur early in service or can be generated under a variety of laboratory testing conditions including thermal cycling (premature failures), isothermal aging (high temperature storage), and mechanical testing. There are major initiatives by electronics industry consortia as well as research by individual companies to eliminate these fracture phenomena. Despite these efforts, interfacial fractures associated with Ni/Au surface finishes continue to be reported and specific failure mechanisms and root cause of these failures remains under investigation. Failure analysis techniques and methodologies are crucial to advancing the understanding of these phenomena. In this study, the scope of the fracture problem is illustrated using three failure analysis case studies of brittle interfacial fractures in area array solder interconnects. Two distinct failure modes are associated with Ni/Au surface finishes. In both modes, the fracture surfaces appear to be relatively flat with little evidence of plastic deformation. Detailed metallography, scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and an understanding of the metallurgy of the soldering reaction are required to avoid misinterpreting the failure modes.

Area Array Solder Joints for Passive Alignment

1992 ◽  
Vol 264 ◽  
Author(s):  
John McGroarty ◽  
Boris Yost ◽  
Peter Børgesen ◽  
Che-Yu Li
Keyword(s):  
Optical Interconnects ◽  
Solder Joints ◽  
Cost Effective ◽  
Scientific Basis ◽  
Electronic Packages ◽  
Liquid Solder ◽  
Area Array ◽  
Cost Effective Method ◽  
Passive Alignment

AbstractPassive alignment techniques using area array solder joints are currently under investigation as a cost effective method of achieving electro-optical interconnects in electronic packages. Several investigators have developed models that describe the shapes of and forces produced by the liquid solder drops during reflow. These models are reviewed to provide a scientific basis for the application of such techniques.

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