Solder joint fatigue models: review and applicability to chip scale packages

A review of fourteen solder joint fatigue models is presented here with an emphasis on summarizing the features and applications of each fatigue model . The models are classified into five categories: stress-based, plastic str ain-based, creep strain-based, energy-based, and damage-based. Fatigue mode ls falling outside these categories are categorized as 'other empirical mod els'. Each model is presented under one category with the relevant paramete rs and applicable packages. Following each category, common issues such as thermal cycling conditions, solder joint geometry, and coverage are address ed. Two fatigue model application scenarios are discussed. In the first sce nario, a set of existing fatigue test data is given to the engineer who mus t determine how best to interpret the data and which fatigue model(s) best apply. In the second scenario, a test scheme must be devised for a new chip scale package product. The number of cycles to failure (N-f) or Fatigue li fe must be determined. A general procedure is presented for choosing an app ropriate fatigue model(s) based on the package conditions and limited Finit e Element Analysis time. This procedure is summarized in a flowchart. (C) 2 000 Elsevier Science Ltd. All rights reserved.