In a method of manufacturing a semiconductor device, an initial structure is provided. The replicas of the pulses, relatively delayed in time, are generated by an interferometer. An address selector selects and outputs an external address to the memory cell array, in response to the activation of the mode register set signal, during the automatic refresh operation in the test mode. A fluid return line is connected between the mixing unit and at least one of the interim tank and the ink tank, the mixing unit receiving fluid from at least one of the interim tank and the ink tank and mixing the fluid with the high solids content ink. The apparatus reproduces a partial signal having a length of time based on the weight point and the period of time. According to the invention, a fastening element is provided that couples both coupling covers.