| 摘要 |
PURPOSE:To secure the connection between an upper- and lower-layer copper conductors and reduce the connection resistance and improve the connection reliability between the conductors by contriving such a structure that part of a different kind of metallic film on the boundary between the copper conductors connected to each other through an interlayer layer is removed so that the copper conductors can be directly connected to each other. CONSTITUTION:This hybrid circuit board comprises thin film circuits 2 and 3 formed on the surface of a thick substrate 1. Each layer is formed by the same forming method. After a Cr and Cu films are formed on the first-layer circuit 2 as base films for plating by a sputtering method, a photosensitive photoresist film is applied to the base films for plating as plating resist films and the plating resist films are patterned by exposure and development. Then, after removing the Cu and Cr from a part 10 where upper- and lower-layer conductor wirings are connected by irradiating the part 10 with a YAG laser beam, copper wiring 9 is formed by electrical plating by using the plating base films as cathodes. The parts from which the plating resist is removed are filled up with a polyimide material as an insulating film. |
