Sebastian Brand

For a couple of decades now acoustic microscopy is a relevant and widely used technique in quality assessment, technology development and microelectronic failure analysis. Due to its non-destructive mode of operation, it allows for contactless defect localization, full range quality screening as well as for repetitive screening and thus enables comprehensive investigations of material behaviors under normal operation- and harsh conditions. Those abilities render it particularly relevant in the context of advanced packaging and heterogeneous integration key aspects of next generation microelectronics.

In acoustics the contrast mechanism is based on the excitation and propagation of elastic mechanical waves which interact with interfaces and particles of differing mechanical properties where they get reflected and scattered. Since elastic waves have the ability of penetrating and propagating in opaque materials, imaging and characterization becomes possible without the need of destructive sample preparation to remove intermediate material layers. In microelectronics related applications microscopic imaging resolutions are necessary and thus require the employed acoustic wave fields to be tuned in frequency and appropriately focused into the depth of interest.

The tutorial introduces the basic principles of scanning acoustic microscopy relevant for inspection of microelectronic devices on package-, chip- and waver level. This includes the operational modes C-scan, B-scan, and through-scan in combination with the excitation and propagation phenomena of acoustic waves in solid media as well as the techniques and requirements necessary for appropriate focusing to obtain optimum inspection and analysis resolution for identifying defects such as delaminations, voids, cracks or inclusions. The fundamentals and specific details of the individual approaches will be illuminated along with demonstrations based on selected representative failure analysis cases. In addition, ongoing developments including the application of machine learning approaches employed for signal analysis and interpretation, automation and extended operator support will be presented with respect to the application in metrology and failure analysis.

Attendees will gain practical knowledge for interpreting acoustic signals and images, selecting appropriate parameters for different applications, and understanding the capabilities and limitations of acoustic microscopy inspection. This tutorial is intended for engineers, analysts, and researchers involved in microelectronics failure analysis, reliability engineering, and advanced packaging development.

Sebastian Brand is a senior scientist at the Fraunhofer IMWS, where he leads a research-, development and application team for non-destructive defect localization in the field of failure analysis and metrology. Sebastian holds a Ph.D. in electrical engineering which he received in 2004 from the University of Magdeburg, Germany. In 2004 and 2005 he joined the University of Toronto and Ryerson University in Toronto, Canada as a post-doctoral fellow working in the field of cancer research.
Sebastian has 19 years of experience in the field of acoustics in life- and material sciences and authored /coauthored more than 60 publications in this and adjacent research fields. His current research extends from acoustic methods over Lock-In-Thermography to magnetic imaging where he and his team undertake research and development for non-destructive defect localization and characterization.