A superjunction can have much lower specific on-resistance, RONSP, for a given breakdown voltage, VBR, as compared to a one-dimensional (1-D) p-n junction. However, the VBR of a superjunction whose parameters are optimized to yield the least RONSP for the specified VBR falls drastically for even small charge imbalances. Hence, a structure fabricated with these target parameter values often has a VBR much lower than specified due to the charge imbalance caused by random process variations. We give an analytical solution for alternate target parameter values which yield the specified VBR in spite of process variations, with minimum sacrifice in RONSP. Although illustrated for 4H-SiC structures with VBR of 1-10 kV, our solution should work for any semiconductor after material specific changes.