THz radiation is capable of penetrating most of nonmetallic materials and allows THz spectroscopy to be used to image the interior structures and constituent materials of wide variety of objects including Integrated circuits (ICs). The fact that many materials in THz spectral region have unique spectral fingerprints provides an authentication platform to distinguish between authentic and counterfeit electronic components. Counterfeit and authentic ICs are investigated using a high-speed terahertz spectrometer with laser pulse duration of 90 fs and repetition rate of 250 MHz with spectral range up to 3 THz. Time delays, refractive indices and absorption characteristics are extracted to distinguish between authentic and counterfeit parts. Spot measurements are used to develop THz imaging techniques. In this work it was observed that the packaging of counterfeit ICs, compared to their authentic counterparts, are not made from homogeneous materials. Moreover, THz techniques were used to observe different layers of the electronic components to inspect die and lead geometries. Considerable differences between the geometries of the dies/leads of the counterfeit ICs and their authentic counterparts were observed. Observing the different layers made it possible to distinguish blacktopped counterfeit ICs precisely. According to the best knowledge of authors the reported THz inspection techniques in this paper are reported for the first time for authentication of electronic components.
Wide varieties of techniques such as X-ray tomography, scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and optical inspections using a high resolution microscope have also been being employed for detection of counterfeit ICs. In this paper, the achieved data from THz material inspections/ THz imaging are compared to the obtained results from other techniques to show excellent correlation. Compared to other techniques, THz inspection techniques have the privilege to be nondestructive, nonhazardous, less human dependent and fast.