Abstract: A quantum device capable of effectively cooling a quantum chip and an area (e.g., a space) therearound is provided. A quantum device includes a quantum chip and an interposer on which the quantum chip is located. The interposer includes an interposer substrate and an interposer wiring layer. The interposer wiring layer is disposed on a surface of the interposer substrate on a side on which the quantum chip is located. The interposer wiring layer includes, in at least a part thereof, a superconducting material layer formed of a superconducting material and a non-superconducting material layer formed of a non-superconducting material.

Abstract: A method of manufacturing a semiconductor device includes the steps of forming barrier metals on first electrodes provided on a chip of the semiconductor device, implementing a predetermined test on the semiconductor device by applying a signal to the semiconductor device via at least one of the barrier metals, and forming second protruded electrodes on the barrier metals. The predetermined tests are implemented before forming second protruded electrodes on the barrier metals.

Abstract: A method of manufacturing a semiconductor device includes the steps of forming barrier metals on first electrodes provided on a chip of the semiconductor device, implementing a predetermined test on the semiconductor device by applying a signal to the semiconductor device via at least one of the barrier metals, and forming second protruded electrodes on the barrier metals. The predetermined tests are implemented before forming second protruded electrodes on the barrier metals.

Abstract: A method of manufacturing a semiconductor device includes the steps of forming barrier metals on first electrodes provided on a chip of the semiconductor device, implementing a predetermined test on the semiconductor device by applying a signal to the semiconductor device via at least one of the barrier metals, and forming second protruded electrodes on the barrier metals. The predetermined tests are implemented before forming second protruded electrodes on the barrier metals.

Abstract: A magnetooptical recording method for overwriting information on a magnetooptical recording medium, which has a first magnetic layer and a second magnetic layer having a larger coercive force and a lower Curie temperature than those of the first magnetic layer, comprises an initialization step of initializing magnetization of the first magnetic layer in one direction, a first recording step of radiating a light beam by repeating radiation and non-radiation states of the laser beam, while applying a bias magnetic field after the initialization step, a second recording step of continuously radiating a light beam while applying a bias magnetic field in a direction opposite to the one direction after the initialization step, and a step of selecting one of the first and second recording steps in accordance with recording information.

Abstract: A magnetooptical recording medium has first and second magnetic layers laminated in that order on a transparent substrate on which a received laser beam is incident. The coercive force of the second magnetic layer is greater than that of the first magnetic layer and is greater than .sigma..sub.w /2M.sub.s2 h.sub.2, where .sigma..sub.w is the magnetic wall energy between the first and second magnetic layers, M.sub.s2 is the saturation magnetization of the second magnetic layer, and h.sub.2 is the film thickness of the second magnetic layer. The coercive force of the first magnetic layer is greater that .sigma..sub.w /2M.sub.s1 h.sub.1, where M.sub.s1 is the saturation magnetization of the first magnetic layer and h.sub.1 is the film thickness of the first magnetic layer. The compensation temperature of the first magnetic layer is smaller than the Curie temperature of the first magnetic layer. Recording is performed by selectively applying a laser spot, having either a high power or a low power.