Transient thermal techniques as failure analytical tool

New packaging technologies are necessary to meet the demand for smaller and more reliable electronic devices. The so-called system-in-package (SiP) concept brings different technologies, material combinations and processes together in one package. To ensure the reliability of such a package reliable, fast and non-destructive failure analysis are needed. Transient thermal methods provide techniques for detection of different types of defects such as delaminations of interfaces, electrical short circuits and voids in die attach layer [1]-[3]. Especially for 3D integration such failures occur inside the system and therefore they are not visible for some failure analytical tools. Scanning acoustic microscopy (SAM) and X-Ray analysis are well-established techniques with some disadvantages. For example, one want to avoid that components are placed in a water bath as it is necessary for SAM investigations. Transient thermal methods were successfully applied to detect very weak thermal responses of joules heat sources in ~ 1 mK range and temperature changes [1] and periodic changing stress field of a crack tip [3]. This work gives an overview of the different analysis algorithms used in transient thermal investigations.