Experimental Characterization of Two-Photon Optical Beam Induced Current Imaging for Microelectronics Assurance

Current post-silicon physical and functional verification and validation strategies that rely on physical delayering of ICs suffer from high cost and time requirements which prohibit assuring microelectronics at scale. Two-photon Optical Beam Induced Current (TOBIC) imaging is a hybrid physical/functional signature useful for non-destructive analysis of integrated circuits from the backside. The approach, however, has been limited by a lack of suitable test targets to quantitatively characterize system performance. Here, we present a custom test target fabricated for TOBIC in a 130 nm CMOS process. TOBIC images are used to estimate the modulation transfer function and resolution of the TOBIC system. The estimated resolution is
$\mathbf{2.5}\ \boldsymbol{\mu} \mathbf{m}$
and agrees with theoretical predictions. Furthermore, we collect TOBIC images of SPI and AES test articles to illustrate TOBIC's applicability to functional circuits.