PURPOSE: To prevent deterioration with time, to stabilize characteristics and to improve reliability, by bonding a function element to a thick film conductor, which is constituted on a insulating substrate through an intermediate layer comprising a nickel metal material, thereby rigidly bonding the function element to the thick film conductor.

CONSTITUTION: For example, in a thick film conductor 24 of silver palladium, an intermediate layer 26 of nickel alcholate, which is an organic metal, is formed at the bonding part of a terminal 28 of a function element such as a transistor and an IC by a printing method including screen printing and the like. The terminal 28 of the function element is soldered on the intermediate layer 26 with brazing filler metal 30. At this time, as the brazing filler metal, a high-melting point brazing filler metal comprising a mixture of silver and tin or a mixture of silver, thin and lead is used. In order to suppress the decrease in conductivity between the thick film conductor 24 and the terminal 28, the thickness of the intermediate layer 26 is made to be 1μm or less, e.g., about 0.5μm. The melting point of nickel is very higher than that of tin. Therefore, the nickel alcholate in the intermediate layer 26 is hardly fuzed and diffused into the side of the brazing filler metal 30 due to the heat when the brazing filler metal is fused.