A semiconductor device substrate assembly may include a first substrate, comprising: a first insulator plate; and a first patterned metal layer, disposed on the first insulator plate, wherein the first insulator plate comprises a first material and a first thickness. The assembly may include a second substrate, comprising: a second insulator plate; and a second patterned metal layer, disposed on the second insulator plate, wherein the second insulator plate comprises the first material and the first thickness. The assembly may also include a third substrate, disposed between the first substrate and the second substrate, comprising: a third insulator plate; and a third patterned metal layer, disposed on the third insulator plate, wherein the third insulator plate comprises a second material and a second thickness, wherein at least one of the second material and the second thickness differs from the first material and the first thickness, respectively.