Thermal deformation measurement of electronic package using advanced moire methods

Abstract

In this paper, the laser moire interferometry method, the electron beam moire method, the atomic force microscope (AFM) scanning moire method, and the scanning electronic microscope (SEM) scanning moire method are used to measure the thermal deformation of electronic packages. The measurement principle and the adaptability of these methods are discussed and compared. 1200 lines/mm holographic gratings in ultra low expansion (ULE) mold plates were replicated on the cross section of the measured sections in a ball grid array (BGA) electronic package and a quad flat package (QFP). These holographic gratings were fabricated on ULE mold plates and were replicated on the measured area at 100/spl deg/C and 150/spl deg/C, respectively. The deformation measurement principles and experimental techniques using these moire methods are described. As an application, the deformation in the different solder joints in the BGA electronic package and in the area near the die corner of the QFP electronic package was measured using these methods. Some useful results were obtained.