Pan Pacific Symposium Conference Proceedings


QUALITY AND RELIABILITY TESTING OF CIRCUIT BOARDS ASSEMBLED WITH LEAD FREE COMPONENTS, FINISHES, SOLDERING MATERIALS AND PROCESSES IN SIMULATED PRODUCTION CONDITIONS

Authors: Sammy Shina, Ph.D., et al.
Date Published: 2/12/2009   Conference: Pan Pacific Symposium


Abstract: The New England Lead-free Electronics Consortium is a collaborative effort of New England companies spanning the electronics supply chain, created by the University of Massachusetts Lowell in 1999 and sponsored by the Toxics Use Reduction Institute and the U.S. EPA. The consortium has completed and published the results of three phases of manufacturing and testing of lead-free Printed Wiring Boards (PWBs) with the goal of achieving zero-defect leadfree soldering processes with comparable or superior reliability to that of leaded solder processes.

In this fourth phase of testing, which began in 2007, several simulated conditions of assembly and rework processes were evaluated in a matrix of multiple levels of components, PWB lead free surface finishes and solders, and compared to a baseline of leaded equivalent materials and processes. Both Through Hole (THT) and Surface Mount (SMT) Technologies were evaluated. The assembly portion of the testing and rework is completed and the long term reliability and vibration is ongoing.

All quality and reliability testing was performed with industry standard methodologies, using specially trained production inspectors for the quality evaluation, and extreme thermal cycling for reliability testing. Our results indicate that with proper selection of currently available (2008) materials and finishes and careful control of the assembly processes, successful lead free assembly and rework can be achieved. Comparison of different strategies for rework, and recommendations for least copper dissolution for THT technology processes are discussed in the published book by the paper authors. Reliability testing to date showed interesting inflection points for leaded versus lead free reliability that has to be resolved by additional thermal cycling, to be published when completed in 2009, together with vibration testing.

Key words: Lead Free, Visual Inspection, Rework, Reliability testing, Thermal Cycling, Design of Experiments.



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