Surface insulation resistance (SIR) response to various processing parameters

SIR testing is in practice carried out under a wider range of experimental conditions than those detailed in standards. The work presented here explores some of the issues when using a range of fluxes with various processing conditions and also examines the influence of substrate finish, test bias and the reflow process. These results clearly show that care must be exercised when using different test set‐ups, and when extrapolating between testing and use conditions. In particular the use of a 50V test bias voltage can produce anomalous results when compared to a 5V use environment.