Detection and resolution enhancement of laser induced fault localization techniques

Abstract

The 2 keys limiting factors for the application of laser induced fault localization detection systems on advanced technology node below 90 nm are detection sensitivity and resolution. In this work, sensitivity is enhanced through the development of new localization method and the optimization of pulsed laser with lock-in detection with in-depth theoretical and experimental study. A sensitivity enhancement factor of more than 20 times has been achieved. It is demonstrated on the localization of Cu/Low-k interconnect reliability defects which were otherwise not detectable with conventional laser induced techniques. Resolution is enhanced by optimizing Refractive Solid Immersion Lens (RSIL) technology for backside failure analysis. Spatial resolution down to 300 nm has been achieved with additional signal enhancement of approximately 15 times. Combining lock-in detection with RSIL, the significant enhancement in detection sensitivity and localization precision was demonstrated on 65 nm microprocessor devices.