Backside and Topside OBIRCH Defect Localization on Multi-layer Finger Structure MOSFET Capacitor with the aid of Focused Ion Beam (FIB)

Abstract

Fault localization using backside OBIRCH (Optical Beam Induced Resistance Change) on metal finger structures is not always effective, especially when the Integrated Circuit (IC) device is composed of multiple metal layers and the defect is located on the mid or upper metal lines. The use of both backside and topside OBIRCH techniques is a known effective approach that increases the success rate in determining the failure mechanism for these cases. However, fault isolation systems are either configured for backside or topside method only. In the Maxim Integrated Philippines Failure Analysis laboratory, only the backside OBIRCH system is available. Thus, defect localization on faulty internal nodes becomes a challenge when only one type of fault isolation system configuration is available. This study presents a new method by doing FIB (Focused Ion Beam) circuit edit to enable topside OBIRCH using the available backside-configured OBIRCH system. The new method was found to be an effective alternative in resolving particle-related problem on multi-layer finger metal structure MOSFET capacitor.