| 摘要 |
PURPOSE:To set the length of the weak coupling part formed later in the prescribed thickness by employing a plasma etching using a gas having an etching rate of an insulator higher than that of a superconductor and a plasma etching using inert gas continued to the previous plasma etching when a thin superconductor film of the uppermost layer forming a Josephson junction element is sputter cleaned. CONSTITUTION:The first thin superconductive film 2 is covered with superconductive substance such as Nb, Ta on a substrate 1, and the second thin superconductive film 4 is formed through an insulator layer 3 such as SiO2 or the like on the film 2. Before a weak coupling part 5 of the prescribed pattern is formed with weak coupling material such as Nb, Bi or the like on the film 4, it is necessary to sputter clean the oxidized film produced when the film 4 is formed. At this time the cleaning is performed by plasma using active gas such as CF4, F2F6 of high etching rate of the insulator layer than the superconductor film and plasma etching using inert gas is then performed. |
