A test program debugging apparatus of the present invention includes a device under test simulator and a semiconductor testing apparatus simulator. A cleaning and sterilizing unit is provided between the outlet end of the emptying station and the inlet end of the filling station. A batched request is allowed to indicate that it depends on the response to another request. The processor may forward the frame to a first loop if the address field of the frame is associated with the first loop. In a first alternative method, an ammonia high-temperature treatment is conducted to remove undesirable impurities within the refractory metal nitride layer lining the contact hole and to replace the impurities with more nitrogen.