Noninvasive Localization of IGBT Faults by High-Sensitivity Magnetic Probe With RF Stimulation

• Published in: IEEE transactions on instrumentation and measurement Vol. 67; no. 4; pp. 745 - 753
• Main Authors: Mai-Khanh, Nguyen Ngoc, Nakajima, Shigeru, Iizuka, Tetsuya, Mita, Yoshio, Asada, Kunihiro
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analysis; Bias; Circuit faults; Cleanrooms; CMOS; detection; downconversion; fault; gate; inductor; Insulated gate bipolar transistors; insulated-gate bipolar transistor (IGBT); integrated circuit; Leakage currents; Localization; Logic gates; Low pass filters; low-noise amplifier (LNA); Magnetic circuits; Magnetic fields; magnetic probe; Magnetic probes; Magnetoelectric effects; mixer; Modules; noninvasive; pickup coil; Pickup coils; position; Probes; Scanning; Sensitivity; sensor; Silicon carbide; Silicon substrates
• ISSN: 0018-9456; 1557-9662
• DOI: 10.1109/TIM.2017.2789038

This paper presents a new and simple method to noninvasively localize failure sites in an insulated-gate bipolar transistor (IGBT) module by using a magnetic probe. The method detects the magnetic field generated by leakage currents occurring at the broken gates of an IGBT module. In this method, not only an RF stimulus signal but also a dc bias voltage is applied to the IGBT module under test, because the resistance of the failure site's change depends upon the dc bias condition. A high-sensitivity magnetic probe is used to detect the magnetic field to locate the corresponding fault positions. The magnetic probe is fully integrated onto a chip by a 180-nm CMOS process and includes a magnetic pickup coil, a low-noise amplifier, a downconversion mixer, and a low-pass filter. Magnetic scanning experiments are implemented for two kinds of IGBT module samples to demonstrate the detection of the broken gate positions. In addition, a visual confirmation of the broken gate positions is performed. Several postprocessing steps in a clean room are applied to these samples in order to visually confirm the scanning results of the proposed method. Experimental results successfully demonstrate that our method can be used for noninvasive localization of small intrinsic faults, on two kinds of SiC and Si substrates, of IGBT modules.