Development of a New Automatic Fault Diagnosis System for Fine Pattern Transmission Lines

This paper presents a new automatic fault diagnosis and detection system for fine pattern interconnects. It is verified by performance of the proposed system for COFs (chip-on-films) with width of less than 20 mu m and pitch of less than 25 mu m as fine pattern transmission lines. The proposed system detects and diagnoses variety of faults such as open, short, near open (mouse bite) and near short (soft short) after fabrication cycle of fine pattern transmission lines. This system consists of RF source, variable gain amplifier (VGA), multi-lead probe card, AC generator, Look-Up Table (LUT), signal processing block, and monitoring block. It also utilizes new techniques to differentiate very small voltage changes due to the faults using VGA and programmable gain amplifier (PGA), and to detect barely detectable far-end near open and near short faults. The proposed system showed very low test overhead and significantly high fault coverage as conventional test systems. It is expected that this system is an effective alternative to decrease test overhead and increase fault coverage for the fine pattern transmission lines.