Probabilistic Failure Modes Characterization for Viscoelastoplastic IC Packages

• Main Authors: Hsien-Shun Huang, 黃顯順
• Other Authors: Hsin-Yi Lai
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/65897574055713971448

碩士 === 國立成功大學 === 機械工程學系 === 89 === ABSTRACT The increase in circuit density and decrease in volume size in IC packages have emerged as an inevitable trend in recent years. As a result, the reliability of IC packages becomes very stern. The study of impact factors such as the properties of packaging materials, geometric shapes and process parameters on probabilistic failure of IC packages becomes a major research issue. In an attempt to increase packaging yield, the paper proposes a systematic modeling procedure to characterize probabilistic failure mode, especially induced by thermal-moisture effect. The systematic modeling procedure to establish probabilistic failure modes for various elastic, viscoelastic and elastoplastic material models is first constructed in the report. Two-dimensional eight-node structural brick element models are employed to build a finite element model for TSOPI-48L. Based on moisture diffusion equation, ideal-gas equation and the plate theory, the constructed model is used to evaluate moisture content and popcorn crack of the packages for various packaging materials and different parameters for reflow soldering processes. The energy release rate, the J integral and the crack tip displacement of cracking are evaluated by using the theory of fracture mechanics. Both experimental results and numerical modeling solutions are applied to fit the failure data using Weibull distribution functions. The model parameters are accurately evaluated by the total least squares method. Probabilistic failure models thus developed are then used for package redesign, process parameters improvement and reliability enhancement of the packages. The computed solutions obtained from the study are compared with those of experimental results and the solutions given in the literature. It was found that the results obtained by the proposed method, experimental data and literature data all agree well with each other. The theory and the modeling procedure can then be used to predict the failure of hygrothermal effect of IC packages. They can also be used for package redesign, improvement of process parameters and prevention of package failure.