METHOD AND APPARATUS FOR MEASURING THERMAL WARPAGE

摘要

A method and apparatus (10) for measuring thermally induced warpage in test elements (27) such as printed wiring boards and printed wiring assemblies, including a heating chamber (11) having a transparent window (17) and support structure (21) for supporting a printing wiring board in an observation orientation and position parallel to the transparent window (17). A glass grating (18) placed adjacent the window (17) and a light source (53) shines through the window (17) onto the printed wiring board (27) under test. A camera (49) is positioned for capturing images of shadow moiré fringes formed over time as the heating chamber (11) heats up the printed wiring board or printed wiring assembly (27) to simulate actual process conditions. A computer (37) is used for controlling operation of the apparatus (10) and for evaluating the captured images of the moiré fringes in relation to the temperature as a function of time.