Dynamic optical beam induced current variation mapping: A fault isolation technique

• Published in: Microelectronics and reliability 2020-04, Vol.107, p.113603, Article 113603
• Main Authors: Thor, M.H., Goh, S.H., Yeoh, B.L., Hao, Hu, Chan, Y.H., Lin, Zhao
• Format: Article
• Language: English
• Subjects: Cross correlation; Digital pixel binning; Dynamic electrical fault isolation; Laser-assisted Device Alteration (LADA); Optical beam induced current (OBIC)
• ISSN: 0026-2714; 1872-941X
• DOI: 10.1016/j.microrel.2020.113603

In this paper, we describe the concept and applications of a dynamic laser stimulation technique based on optical beam-induced current (OBIC) variation mapping for global fault localization. A production tester exercised the chip dynamically while a 1064 nm wavelength laser interrogates the devices in the region of interest from the chip backside. OBIC variations at different test cycles are recorded for every scanned pixel and translated into a current profile. A post-processing scheme then determines the suspected defect location. Unlike laser-assisted device-alteration (LADA) which uses the same laser, this technique applies to hard defects localization. Five case studies will be presented as proof of concept. •Concept and applications of a new dynamic laser stimulation technique based on optical beam-induced current (OBIC) variation mapping•Fault isolation is accomplished by applying an offline post-processing scheme to the OBIC profiles to discriminate abnormal sites•Post-processing scheme can be either thresholding or a combination of digital pixel binning and cross-correlation•This technique has been proven effective on both open and short defects on embedded memory and ATPG's real test cases•Key advantage lies in reuse of readily available production test patterns and does not require any additional detection system