Modeling of board-level package by Finite Element Analysis and laser interferometer measurements

Board-level package is a complicated multi-components structure. It can be simulated by an equivalent Finite Element Analysis (FEA) model of the board-level package, in which detailed layer structure of the Print Circuit Board (PCB), signal wires and through-holes were ignored. For this purpose, it is necessary to obtain the equivalent material properties of the board-level package. In this work, a laser-based interferometric technique was used to measure the modal parameters of the board-level package. By fitting the FEA results with the experimental results, we can obtain equivalent material properties of the board-level package by means of the Taguchi method. Four control factors (Young's modulus in the x and y direction, mass density and shear modulus in the xy plane) at three levels are explored and assigned to the columns of a L₉(3⁴) saturated orthogonal array. The so obtained equivalent parameters provided the best fit between the FEA results and the experimental observations.