Semiconductor device and system having semiconductor device mounted thereon

Abstract

There is provided a semiconductor device that is capable of reducing wring density of the wiring pattern on a mounting board on which it is mounted, thereby facilitating routing of the wiring pattern. Pads are formed which are connected to pads on a bare chip by bonding wires. There are formed vias extending from the respective pads to a bottom surface of a package, and vias extending from the respective pads to a top surface of the package. This makes it possible to connect the mounting boards to the top and bottom surfaces of the package, thereby enabling reduction of the wiring density of wiring patterns on the mounting boards, thereby facilitating routing of the wiring patterns on the mounting boards.

1 . A method of mounting a semiconductor device having pads formed on a top surface and a bottom surface of a package thereof, the pads being provided for mounting said semiconductor device on a board, 
 the method comprising the steps of:    attaching solder balls having a melting temperature lower than that of solder balls attached to the bottom surface of the package, to the top surface of the package;    connecting a first board to the bottom surface of the package by reflow; and    connecting a second board to the top surface of the package by reflow at a temperature which has reached the melting temperature.    
   
   
       2 . A method of mounting a semiconductor device having pads formed on a top surface and a bottom surface of a package thereof, the pads being provided for mounting said semiconductor device on a board, 
 the method comprising the steps of:    attaching solder balls having a melting temperature lower than that of solder balls attached to the bottom surface of the package, to a first board to be connected to the top surface of the package;    connecting a second board to the bottom surface of the package by reflow; and    connecting said first board to the top surface of the package by reflow at a temperature which has reached the melting temperature.