Projection moiré method and apparatus for dynamic measuring of thermal induced warpage

Abstract

The projection moiré and temperature controlled chamber system houses a workpiece in the chamber and subjects the workpiece to changing temperatures according to a predefined temperature/time profile. As the workpiece is subjected to changing temperatures, a projection moiré system projects a plurality of moiré fringe patterns onto the workpiece, and a camera detects thermally induced warpage in the workpiece. The detection of thermally induced warpage, indicated by changes in the projected fringe moiré patterns on the workpiece, is analyzed by a processing unit. The temperature controlled chamber includes a plurality of heating sources, at least one cooling source, temperature probes and an adjustable support frame. Output temperature of the heating/cooling sources may be variable. The position of the support frame is adjustable and controlled by the processor in a manner such that a reference point associated with the workpiece or the frame is held in a stationery manner. The chamber may also include a plurality of air blowers and exhaust vents to facilitate temperature control within the chamber. An alternative embodiment includes a supplemental shadow moiré system.