Resin-molded semiconductor device and method for manufacturing the same

Abstract

A semiconductor chip ( 15 ) is bonded on a die pad ( 13 ) of a leadframe, and inner leads ( 12 ) are electrically connected to electrode pads of the semiconductor chip ( 15 ) with metal fine wires ( 16 ). The die pad ( 13 ), semiconductor chip ( 15 ) and inner leads are molded with a resin encapsulant ( 17 ). However, no resin encapsulant ( 17 ) exists on the respective back surfaces of the inner leads ( 12 ), which protrude downward from the back surface of the resin encapsulant ( 17 ) so as to be external electrodes ( 18 ). That is to say, since the external electrodes ( 18 ) protrude, a standoff height can be secured in advance for the external electrodes ( 18 ) in bonding the external electrodes ( 18 ) to electrodes of a motherboard. Thus, the external electrodes ( 18 ) may be used as external terminals as they are, and no ball electrodes of solder or the like need to be provided for the external electrodes ( 18 ). Accordingly, this process is advantageous in terms of the number of manufacturing process steps and the manufacturing costs.

1 . A resin-molded semiconductor device comprising: 
 a semiconductor chip having electrode pads;    inner leads;    connection members for electrically connecting the electrode pads of the semiconductor chip to the inner leads; and    a resin encapsulant for molding the semiconductor chip, the inner leads and the connection members together,    characterized in that the lower part of each said inner lead, including at least part of the back surface thereof, functions as an external electrode, the external electrode protruding downward from the back surface of the resin encapsulant.    
     
     
         2 . The resin-molded semiconductor device of    claim 1   , further comprising: 
 a die pad for supporting the semiconductor chip thereon; and    support leads for supporting the die pad,    characterized in that each said support lead includes a depressed portion for elevating the die pad above the inner leads.    
     
     
         3 . The resin-molded semiconductor device of    claim 1    or    2   , characterized in that a protrusion height of the external electrode as measured from the back surface of the resin encapsulant is in the range from 10 μm to 40 μm.