Thermally-induced warpage measurement on small packages by a microscopic fringe projection system

Existing techniques for measuring thermomechanical warpage of electronic component packages run into limitations when the package size falls below 10 mm on a side. This paper presents a microscopic fringe projection technique to measure the warpage of small area substrates under thermal loading. A stereomicroscope is used as a platform to extend the measuring range of the fringe projection technique to micron-scale resolution in the X, Y, and Z dimensions at its highest magnification. The optical measurement system has been integrated with existing temperature-control equipment to control sample temperature from 25degC to 300degC. System design issues are discussed and experimental results demonstrate the feasibility of the proposed system. This research will result in a rapid, full-field, and low-cost method for characterizing the thermomechanical behavior of millimeter-scale devices