Measuring propagation delays of critical paths using time-resolved LADA

Laser-assisted device alteration is an established technique used to identify critical speed paths in integrated circuits. By using a synchronized pulsed laser, logic transition waveforms have been acquired that can be used to measure propagation delays of the critical path signals. A method for determining the polarity of the transitions is presented for LADA sites on bulk 28nm CMOS technology. The time-resolved LADA logic waveforms are compared to, and are in close agreement with, laser voltage probe waveforms acquired from the same device.