A Standard Multilayer Printed Wiring Board for Material Reliability Evaluations
This paper details the Alcatel-Lucent Pb-free Material Reliability Test board (MRT) used in two different High Density Packaging User Group tests covering 56 different constructions and in numerous other independent material analysis studies [1-7]. In total,this test vehicle has been used in over 80 different material evaluations (and still growing) encompassing materials from almost every major material manufacturer and fabricated by multiple PWB manufacturers. The test vehicle,currently in its 5th generation (MRT-5),is very comprehensive and includes sections for evaluation of material survivability through Pb-free reflow at different via hole pitches,air-to-air thermal cycling,interconnect stress testing (IST) – including the new DELAM methodology introduced by PWB Interconnect Solutions [5,9],conductive anodic filament (CAF) evaluation,moisture sensitivity and its effect on Pb-free reflow survivability,electrical characterization,provides BGA pads for pad pull testing,and incorporates specific design features to enable characterization of material properties (such as DMA) in a multilayer construction in a consistent manner. The design is flexible including 3 different standard constructions and resin contents (12 layer,and 20 layer with 2 different constructions) and can be adapted to other configurations if necessary. This paper presents the design and provides example results and information on how to evaluate these results. The design is made available to all in the industry to facilitate a standard test methodology – and has been offered to IPC as a standard test vehicle for multilayer material evaluations.