Appendix Formal Proof of Optimum Single Via Placement In this appendix, the Lemma used to determine the optimum via location for an interplane interconnect that includes only one via for different values of r 21 , c 12 , and l. 1 is stated and proved. Lemma 1: If f(x) ¼ Ax 2 þBxþC and d 2 f ð x Þ < 0; dx 2 B