Advanced Fault Isolation Technique Using Electro-optical Terahertz Pulse Reflectometry

Electro-optical terahertz pulse reflectometry (EOTPR) was introduced recently to isolate faults in advanced IC packages. The EOTPR system provides 10 mu m in distance accuracy that can be used to localize package-level open and short failures non-destructively. In this paper, an EOTPR system was used to determine the location of open and short failures and to identify impedance variations in a series of package substrates. The experimental results demonstrate the higher accuracy of the EOTPR system in determining the distance to defect compared to traditional time-domain reflectometry systems. Finally, physical failure analysis was used to verify the accuracy of the EOTPR results.