Next Generation Laser Voltage Probing

We present an overview of Ruby, the latest generation of backside optical laser voltage probing (LVP) tools [1, 2]. Carrying over from the previous generation of IDS2700 systems, Ruby is capable of measuring waveforms up to 15GHz at low core voltages 0.500V and below. Several new optical capabilities are incorporated; these include a solid immersion lens (SIL) for improved imaging resolution [3] and a polarization difference probing (PDP) optical platform [4] for phase modulation detection. New developments involve Jitter Mitigation, a scheme that allows measurements of jittery signals from circuits that are internally driven by the IC's onboard Phase Locked Loop (PLL). Additional timing features include a Hardware Phase-Locked Loop (HWPLL) scheme for improved locking of the LVP's Mode-Locked Laser (MLL) to the tester clock as well as a clockless scheme to improve the LVP's usefulness and user friendliness. This paper presents these new capabilities and compares these with those of the previous generation of LVP systems [5, 6].