An apparatus is provided which includes: a first stack including a lower, a middle, and an upper layer of conductive material with insulator layers therebetween, and a second stack including the middle and upper layers with one of the insulator layers therebetween. In an example, a first of the insulator layers has a lower breakdown voltage than a second of the insulator layers. The apparatus further includes a first via over the first stack, wherein the first via is in contact with a pair of the lower, middle and upper layers that have the first of the insulator layers therebetween. The apparatus further includes a second via over the second stack, wherein the second via extends through the upper layer and is in contact with the middle layer. In an example, the second via is isolated from a sidewall of the upper layer by a spacer.