| 摘要 |
PURPOSE:To save use of Au and stabilize quality to providing a sintered body consisting of W or Mo powder or metal powder mainly consisting of W or Mo to a part of an insulating substrate and by providing a B-added Ni layer through the electroless plating and Au layer recrystallized at a lower temperature. CONSTITUTION:A paste mainly consisting of the specified metal powder such as W etc. is printed to a part of an alumina substrate 1, it is inserted and thereby a conductive part 2 is formed, it is then immersed into an aqueous solution of HCl+KF and thereafter washed by water. An element is then immersed into the aqueous solution of gold potassium cyanide + citric acid soda + sodium hydroxide for the Au substitution and then it is washed by water. Next, the Ni film 3 containing phosphorus P of 1% or less and boron B of 0.25-1% is deposited in the thickness of about 5mum by the electroless plating. After is washed by water and is then dried up, the element is heat-processed at a temperature of 650-900 deg.C in the H2 ambient for 30min. Thereby, the layer 3 is re-crystallized in the thickness of about 2-5mum. The electroless plating is then carried out again and thereby the Au film 4 is deposited in the thickness of about 0.1-5mum and the element is washed by water. Moreover, it is heated up to about 300 deg.C and thereby the Au film is re-crystallized. According to this structure, Au can be saved and a casing having good junctionability can be obtained in high quality. |
