A hybrid method using response surface and pattern search for design optimization of microelectronics packaging system

This study presents a new method to construct the response surface function and a new hybrid optimization method. For the response surface function, the radial basis function (RBF) is used for a zeroth-order approximation, while a set of new bases is proposed for the moving least squares (MLS) method for first-order approximation. For the new hybrid optimization method, the gradient-based algorithm and pattern search algorithm are integrated to obtain a robust and efficient optimization process. The hybrid optimization method is based on: (1) multi-point approximation of objective and constraint functions; (2) a multi-quadric RBF for the zeroth-order function representation and/or RBF plus polynomial based MLS approximation for first-order function approximation; and (3) a pattern search algorithm to impose a descent condition. Function approximation examples indicate that the multi-quadric radial basis function and the proposed RBF plus the polynomial based MLS method can yield accurate estimates of arbitrary multivariate functions. Results also show that the developed hybrid method provides efficient and convergent solutions for both mathematical and structural optimization problems.; Microelectronic packaging design is a complex multidisciplinary task. A global-local methodology is presented to predict mechanical deformation and fatigue durability of solder joints in a microelectronic packaging system subject to cyclic thermal loading. This methodology involves global deformation analysis, local critical solder-joint analysis, and fatigue life analysis. Good agreement between the simulated results and experimental observations is obtained. The proposed hybrid method is employed for design optimization of microelectronic packaging. The fatigue life is selected as the objective function and the material properties of the printed circuit board (PCB) and package, and the diameter parameters of the solder joint are selected as the design variables. Different combinations of material properties and shape parameters are evaluated in several case studies. It is observed that material properties and solder ball shape parameters have significant influences to the thermal fatigue life of solder joints. Through design optimization, the durability performance of the microelectronics packaging system is improved significantly.