Circuit analysis may be done by non-destructive imaging alone, but when you need to get to the depths of the problem, you must be able to reliably strip a circuit apart layer by layer. Reactive Ion Etch (RIE) can selectively remove the layers which make up your integrated circuit chip.
Choosing the right gases, plasma power, etc requires experience and experimentation - like perfecting a recipe. First you may choose a recipe to strip the dielectric passivation, then you may choose to strip the top layer of metal interconnects. Using repeated processes like this enable you to accurately reach the critical point of interest for your circuit analysis.
