Design for Manufacture and Test Using Thermal Cycling Under Bias to Measure Electrochemical Reliability on Bottom Terminated Components

Abstract

There are many factors contributing to electrochemical failures on electronic devices including pitch, electrical field, ionic contamination and environmental conditions. Each of these factors is dependent on the installation location, with exposure to varying temperatures and humidity. The interactions of all these factors are quite complex, and being able to predict potential electrochemical failures is challenging. A series of detection and preventive measures from the qualification of solder pastes to controlling the ionic contamination levels of the materials in production is needed. The purpose of this research is to characterize this problem by varying humidity and temperature conditions. Humid heat simulates the thermal load of the components under test at high humidity levels with cyclic temperature conditions. Condensation tests verify the design, materials, and remaining electronic circuit residues' resistance to moisture. The test methodology used for this research study will subject the test cards to humid heat and cyclic temperatures with frost conditions. The harsh environment simulates the thermal load including frost cycling to induce low dewing point conditions through cyclic temperature changes at high humidity. Humid environments challenge no-clean electronics and the basis for detecting electrochemical robustness at various points during the design validation testing.