Physical Mask creates an illusion
that affects technological sensors as well.
Just off the cuff, if it could work, the caster would need to know the biometrics he's trying to imitate, the same way you can't passably imitate the face of someone you've never seen. Not so hard for voice. A lot harder for retina, fingerprints, DNA etc. Assuming you had the information you needed, the spellcasting success would be the threshold the sensor needs to beat to see through it.
Then again, since the wording of the spell is that it makes someone look different, rather than that it specifically allows imitation of someone in particular, I might also have the caster make a disguise check. Seeing through the spell reveals the person for who they really are. Seeing through the disguise reveals them as not being the person they're imitating. Electronic sensors would use the lower roll as the threshold, since either will cause the Masked person to fail the biometric check.