The present invention provides a method of fabricating an airgap-containing interconnect structure in which a patternable low-k material replaces the need for utilizing a separate photoresist and a dielectric material. The reducing agent supply device injects the reducing agent in a flat form in a direction intersecting a center line of the NOx catalyst from a nozzle hole disposed in the casing. The retry period increases as the number of retries increases. The second programmable transistor includes a second gate terminal, a second source terminal, and a second drain terminal, and a second programmable terminal. By this configuration, a semiconductor laser can be obtained which operates up to a high power without generating a kink.