Electrical connection through a substrate to a microelectromechanical device

An electrical through-connection, or via, that passes through a substrate (22) to a bus (28) on a first surface (21) of the substrate (22). The via may be configured with an interlock (46) such that the electrically conductive core (60) of the via is constrained to thermally expand towards the second surface (23), away from the bus (28), thus preventing damage to the bus (28). The interlock (46) may be a local constriction or enlargement of the via near the first surface (21) of the substrate (22). The via may be greater in length along the bus (28) than a unit spacing of beams (30) in a parallel microswitch array (20) actuated in unison along the bus (28). The via may be narrower in width than in length, and may form a trapezoidal geometry that is larger at the second surface (23) of the substrate (22) than at the first surface (21).