Online proceedings - EDA Publishing Association

24-26 September 2008, Rome, ItalyMaterial Characterization and Non-Destructive FailureAnalysis by Transient Pulse Generation andIR-ThermographyD. May 1 , B. Wunderle 1 , M. Abo Ras 1 , W. Faust 1 , A. Gollhard 3 , R. Schacht 1,2 , B. Michel 11 Fraunhofer Institute Reliability and Microintegration, Volmerstraße 9 B (1.OG), 12489 Berlin, GermanyEmail: daniel.may@izm.fraunhofer.de2 Fachhochschule Lausitz (University of Applied Sciences Lausitz), 01968 Senftenberg, Germany3 AMIC Angewandte Micro-Messtechnik GmbH, Volmerstraße 9B, 12489 BerlinAbstract-IR-thermography has become increasingly importantfor non-destructive testing of microelectronic devices andstructures on chip, package and board-level. This paper focuseson the evaluation of best applicability for different pulse excitationmodes to detect flaws and damages as well as to determinematerial properties. Pulse IR thermography using electricaland laser excitation was chosen as an analytic method to observeand quantify crack growths in vias under thermal cyclingload. We found that cracks are detectable unambiguously andits advantage over the ohmic test. The laser excitation in contrastto the electrical excitation has a good potential for largescalescreening as the board can be stepwise thermally excitedand screened in one go without having any additional measuringlines. A new concept detecting crack tips was demonstrated.I. INTRODUCTIONShort time to market and product expectations rise regardingsystem reliability provide need for fast and accurate failureanalysis in industry. Parametric lifetime model helps todesign reliable products. In order to have good statements oflifetime, these models have to be validated experimental. Sofar people use x-ray, ultrasound microscopy, optical microscopy,grayscale correlation and destructive methods likecross sectioning. All these methods have shortcomings theyare destructive, sometimes not applicable or deliver low contrast.Infrared thermography could be used to complementthese other methods. The combination of two or more methodshelps to increase accuracy of failure analysis. Advantagesof IR-thermography are non-destructive, intuitive contrastand surface-tolerant. It can be used with many differentenergy excitation methods (ultra sonic, light, laser, flash,electric). This opens a lot of new possibilities. These possibilitiesshould be tested and investigated as well as explainedand understood physically. Therefore we have tested theseanalysis methods and designed experimental setups, whichare suitable for real applications what also can be relevantfor industry test field examinations.II.A. Infrared CameraEQUIPMENTIn non destructive analysis of electronic components andsystems an IR camera with high time resolution and lowNETD is necessary to measure very small differences intemperature. The detector area of the used camera is build upof 640 x 512 pixels. The geometrical resolution goes up to 8µm per pixel using certain macro objectives. Depending onthe temperature range and the amount of pixel a frame rateof up to 20 kHz is possible as shown in Fig. 1. The higher atemperature of a scene is the higher frame rate can beachieved. Because of the frame rate is correlated with theexposure time of IR-detector.Fig. 1 State of the art IR-Camera and its technical detailsDepending on application passive or active IR- thermographyis used. For active pulse- or lock-in thermographydifferent excitation sources are available. Therefore flashlights, diode laser, ultra sonic, eddy current and electricalcurrent sources are available.©EDA Publishing/THERMINIC 2008 47ISBN: 978-2-35500-008-9