A method for designing a base includes (1) selecting a location of a first center of expansion of a child part (CE.sub.child) relative to a parent part; (2) determining a location of a second center of expansion of a bond joint (CE.sub.bond) bonding the child part to the base; and (3) determining a location of a third center of expansion of the base (CE.sub.base) on a centerline, which is defined by the CE.sub.child and the CE.sub.bond, so the CE.sub.child does not substantially move relative to the parent part under a temperature change. To determine the location of the CE.sub.base, the method further includes (a) determining a length change to the child part from the CE.sub.bond to the CE.sub.child under the temperature change; (b) determining a length of the base that produces the same length change under the temperature change; and (c) locating the CE.sub.base at the length away from the CE.sub.bond.