Method and apparatus for measuring thermal warpage

A method for measuring thermally induced warpage in specimens using a heating chamber for housing and heating a specimen, an illumination source, a grating, and a camera, the method comprising the steps of:

• placing and supporting the specimen in the heating chamber;
• illuminating the specimen with light from the illumination source directed through the grating onto the specimen, thereby forming shadow moire fringes on the specimen;
• capturing a first image of the shadow moire fringes with the camera;
• heating the specimen in the heating chamber to cause the temperature of the specimen to follow a desired temperature profile over a period of time;
• capturing subsequent images of shadow moire fringes with the camera over the period of time while also recording the temperature of the specimen over the period of time;
• and
• determining the warpage of the specimen as a function of temperature by evaluating the first image of shadow moire fringes, the subsequent images of the shadow moire fringes captured over the period of time, and the temperature of the specimen recorded over the period of time.