Laser Voltage Probe (LVP): A Novel Optical Probing Technology for Flip-Chip Packaged Microprocessors

Abstract

Abstract A novel optical probing technique to measure voltage waveforms from flip-chip packaged complementary metal-oxide-semiconductor (CMOS) integrated circuits (IC) is described. This infrared (IR) laser based technique allows signal waveform acquisition and high frequency timing measurement directly from active PN junctions through the silicon backside substrate on IC’s mounted in flip-chip, stand-alone, or multi-chip module packages as well as wire-bond packages on which the chip backside is accessible. The technique significantly improves silicon debug & failure analysis (FA) through-put time (TPT) as compared to backside electron-beam (E-beam) probing because of the elimination of backside trenching and probe hole generation operations.