2017 Volume 2 Pages 71-75
Electronic packages are composed of various components that have different coefficients of thermal expansion (CTE) values. Thermal strain occurs due to CTE mismatch of the components. However, when the thermal strain distributions are measured by digital image correlation (DIC), a periodical measurement error is observed. In this study, a displacement measurement method with periodical error elimination is applied to the measurement of thermal strain in an electronic package structure. In this method, rotated and multiple translated images in the horizontal and vertical directions are used to determine actual translation amounts. The periodical errors are eliminated using the relation between measured and actual translation amounts. As a result, the periodical errors in the measured thermal strain distributions on a test specimen can be eliminated, and measurement spatial resolution and accuracy are improved. In addition, precise thermal strain distributions can be observed. This method is effective for in-plane thermal strain measurement of electronic packages.
