Abstract
To verify the reliability of a typical Pb-free circuit board applied for space exploration, five circuits were put into low temperature and shock test. However, after the test, memories on all five circuits were out of function. To investigate the cause of the failure, a series of methods for failure analysis was carried out, including X-ray detection, cross-section analysis, Scanning Electron Microscope (SEM) analysis, and contrast test. Through failure analysis, the failure was located in the Pb-free (Sn-3.0Ag-0.5Cu) solder joint, and we confirmed that the failure occurred because of the low temperature and change of fracture characteristic of Sn-3.0Ag-0.5Cu (SAC305). A verification test was conducted to verify the failure mechanism. Through analyzing data and fracture surface morphology, the cause of failure was ascertained. At low temperature, the fracture characteristic of SAC305 changed from ductileness to brittleness. The crack occurred at solder joints because of stress loaded by shock test. When the crack reached a specific length, the failure occurred. The temperature of the material’s characteristic change was −70–−80 °C. It could be a reference for Pb-free circuit board use in a space environment.
Highlights
Because of the importance of space exploration, more and more institutions are turning their research direction to the deep space
Considering the special environmental condition, there may be a variety of composite reliability issues, especially the reliability problems of electronic components operating under low-temperature conditions [1]
The results showed that the components themselves were intact
Summary
Because of the importance of space exploration, more and more institutions are turning their research direction to the deep space. Considering the special environmental condition, there may be a variety of composite reliability issues, especially the reliability problems of electronic components operating under low-temperature conditions [1]. The design of the low-temperature tensile test, corresponding samples of SAC305 material4.2. 9 is the design of the According to the of the low-temperature tensile Figure test, corresponding samplesdrawing of SAC305. According requirements for obtaining the low-temperature mechanical material and clamp to forthe theexperimental tensile test were designed. According to the design of the low-temperature tensile test, corresponding samples of SAC305. According the experimental requirements the low-temperature mechanical characteristics of thetosolder joint, Cu was selected as for the obtaining base material for welding. SAC305 was used material and clamp for the tensile test were designed.
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