Die fracture probability prediction and design guidelines for laminate-based over-molded packages

Abstract

Transferring molding process is widely used in the plastic IC packaging. Die cracking failures due to transfer molding process may occur. In this paper, an investigation on the die fracture and its failure probability is conducted. The approaches and results of die strength characterization, FE modeling on the laminate-based packages, and simulation-based prediction of the die fracture probability rate are presented. Weibull statistics model was used to describe the probability distribution. Model parameters were obtained by fitting to the test results. 3D parametric FE models were established to conduct numerical simulations to predict the stress field and die fracture probability caused during the transfer molding process. For a BGA package, the influence of the solder mask opening under the die on the fracture probability was investigated. For the capped MEMS, high stress levels are induced in the cap and the MEMS die during the molding process. The cavity size, cap thickness, the molding pressure, and the wafer surface finishing process have significant influences on the fracture failure probability. It shows that improvement of die fracture probability can be achieved by changing the designs or the die surface finishing process to meet the reliability requirements.

Thin silicon wafer processing and strength characterization

“…12) [57][58][59][60][61]; In all the methods, the sample is placed on a support, then a load is applied to the top of the sample, and the force at which the sample breaks is recorded. The three-point bend test and four-point bend test are sensitive to edge damage (i.e.…”

An evaluation of die crack risk of over-molded packages due to external impact

“…[2,3] For this work, a 3D finite element model is established using ANSYS for the MAPBGA component to analyze the impact-induced stress and strain distribution within the silicon. Figure 7 is an overview of the implemented model.…”

Chip-side-healing as a basis for robust bare-chip assemblies

“…Because of ever increasing electronic applications especially in safety-relevant systems e.g. for automotive electronic stability control, also rare failure mechanisms like chip fracture, have become more and more of interest [1][2][3]. The chip fracture is essentially determined by two primary parameters.…”

“…For instance, Fig.1 shows stress sensor chips prepared for in situ analysis during the die attachment process [4]. An overview of previous investigations revealed typical silicon die stresses in the range of ±50 MPa up to ±200 MPa [1][2][3][4][5][6][7].…”