Circuit device and manufacturing method therefor

Abstract

A circuit device is made smaller in higher. The circuit device includes a wiring substrate, a first circuit element, and a second circuit element. The circuit substrate includes an insulating resin layer, a wiring layer provided on a main surface of the insulating resin layer, and a wiring layer provided on the other main surface of the insulating resin layer. The wiring layer includes first interconnectors to which the first circuit element connects, and wiring portions. The film thickness of the first interconnector is made thinner than that of the wiring portion. The wiring layer includes second interconnectors and wiring portions. The first interconnectors and the second interconnectors are connected through the medium of conductors.

1 - 6 . (canceled) 
     
     
         7 . A method for manufacturing a circuit device, the method comprising:
 forming a first wiring layer which includes a first interconnector on one face of a substrate;   forming a second wiring layer which includes a second interconnector electrically connected to the first interconnector, the second interconnector being provided on the other face of the substrate;   covering the second interconnector with a metal whose ionization tendency is smaller than that of a metal forming the first interconnector;   forming a pre-flux film on a surface of the first interconnector by subjecting the first interconnector to an organic solderability preservative processing; and   mounting a circuit element on the first interconnector.   
     
     
         8 . A method for manufacturing a circuit device according to  claim 7 , wherein a metal forming the first interconnector is copper and a metal covering the second interconnector is gold. 
     
     
         9 . A method for manufacturing a circuit device according to  claim 7 , wherein said mounting a circuit element is such that the circuit element is connected to the first interconnector using a solder bump. 
     
     
         10 . A method for manufacturing a circuit device according to  claim 8 , wherein said mounting a circuit element is such that the circuit element is connected to the first interconnector using a solder bump.