Method And Apparatus For Measuring Thermal Warpage

Abstract

A method and apparatus for measuring thermally induced warpage in test elements such as printed wiring boards and printed wiring assemblies, including a heating chamber having a transparent window and support structure for supporting a printing wiring board in an observation orientation and position parallel to the transparent window. A glass grating placed adjacent the window and a light source shines through the window onto the printed wiring board under test. A camera is positioned for capturing images of shadow moire fringes formed over time as the oven heats up the printed wiring board or printed wiring assembly to simulate actual process conditions. A computer is used for controlling operation of the apparatus and for evaluating the captured images of the moire fringes in relation to the temperature as a function of time.