1. A structure comprising: a substrate comprising a backside surface; through vias comprising nubs extending from the backside surface; a backside passivation layer coupled to the backside surface, the backside passivation layer comprising only a single layer of material; and circuit features embedded within the backside passivation layer and coupled to the nubs, the circuit features comprising recessed surfaces, at least a portion of the backside passivation layer between the recessed surfaces and a first passivation layer surface of the backside passivation layer.