Contactless Testing of Pulse Propagation in IC’s - A Comparison Between OBIC and Captive-Coupling Detection Techniques

Internal IC probing has become an important tool for failure analysis and defect localization. Optical stimulation of logical transients enables the investigation of electrical pulse propagation through IC-regions which are not directly connected to an external input. The signal detection should be as directly as possible to avoid misinterpretation of experimental results, especially for time-resolved measurements. This paper describes the implementation of a capacitive coupling technique on a laser scanning microscope and on a needle prober. Results of static and time-resolved measurements are presented and compared to those obtained by OBIC measurements.