Requirements specification and verification of environmental protection and life of solder joints to components
|Swerea IVF AB - Avdelningen för materialapplikationer
|Funding from Vinnova
|SEK 4 000 000
|July 2015 - December 2017
|The strategic innovation programme Electronic Components and Systems:
Purpose and goal
The aim of the project has been to develop the knowledge required to ensure the reliability of solder joints for various types of components early in product development by being able to predict, evaluate and verify reliability. The project has provided knowledge about shortcomings of today´s testing methods and how tests should be designed to be more relevant for evaluating reliability. It has also provided knowledge of which components involve the greatest reliability risks and that the choice of conformal coatings/underfill can both deteriorate and improve reliability.
Expected results and effects
The project has shown that tests carried out today can give an overestimation of the life of solder joints and the environmental protection of coated boards. By using more relevant tests, developed and evaluated in the project, better estimates of reliability can be made. The microstructure of lead-free soldering joints affects the life of these. It can vary widely and is affected by, for example, plating on solder pad and solder volume. Cracks in PCBs can also affect life expectancy. Another important result is that acrylic coatings can cause a reduction of up to 90% of solder joint life.
Planned approach and implementation
Test boards for evaluation of test methods and reliability of solder joints to components were designed and manufactured by participating companies in the project according to these companies’ design rules and manufacturing processes. Selection of components and PCBs was also determined by participating companies to ensure that they were representative of true assemblies and of what they use today. These were then tested and evaluated at Swerea IVF after joint decision on which tests were to be performed. Thereby, a high relevance of the results has been ensured.