Semiconductor device

Abstract

In a semiconductor device having a heat radiation plate, the tips of inner leads connected to a semiconductor chip have a lead width w and a lead thickness t, the width being less than the thickness. The inner leads are secured to the heat radiation plate. Fastening the inner leads to the heat radiation plate supports the latter and eliminates the need for suspending leads. A lead pitch p, the lead width w and lead thickness t of the inner lead tips connected to the semiconductor chip have the relations of w<t and p≧1.2 t, with the inner leads secured to the heat radiation plate. The heat radiation plate has slits made therein to form radially shaped heat propagation paths between a semiconductor chip mounting area and the inner leads. In a molding member-sealed semiconductor device wherein the semiconductor chip is fixed to the heat radiation plate, the tip thickness t′ of the inner leads is made less than the thickness t of the other portions of the inner leads secured to the heat radiation plate.

What is claimed is:  
     
         1 . A semiconductor device comprising: 
 a heat radiation plate including a main surface and a back surface opposite to said main surface, said heat radiation plate having slits penetrating from said main surface to said back surface;    a semiconductor chip having a semiconductor element and a plurality of electrodes furnished on a principal plane, said semiconductor chip being fastened to said main surface of said heat radiation plate;    a plurality of leads each having an inner lead and an outer lead, tips of the inner leads being fixed to said heat radiation plate, said inner leads being connected electrically to electrodes of said semiconductor chip; and    a molding member sealing said heat radiation plate, said semiconductor chip, and said inner leads;    wherein said slits are laid out in a radial direction radiating from outside a semiconductor chip mounting area of said heat radiation plate toward a region surrounded by said tips of said inner leads.    
     
     
         2 . A semiconductor device according to  claim 1 , wherein a tip lead width w of said inner leads is less than a lead thickness t of said inner leads.  
     
     
         3 . A semiconductor device according to  claim 2 , wherein a tip lead pitch p of said inner leads is equal to or less than 1.2 times said lead thickness t of said inner leads.  
     
     
         4 . A semiconductor device according to  claim 2 , wherein a tip lead thickness t′ of said inner leads fixed to said heat radiation plate is less than said lead thickness t of said inner leads.  
     
     
         5 . A semiconductor device according to  claim 1 , wherein said slits are fabricated in such a manner that heat propagation paths are formed radially in said heat radiation plate.  
     
     
         6 . A semiconductor device according to  claim 1 , wherein pads of said electrodes are laid out in an alternately arrangement on said semiconductor chip.  
     
     
         7 . A semiconductor device according to  claim 1 , wherein said tips of said inner leads are laid out in an alternately arrangement.  
     
     
         8 . A semiconductor device according to  claim 1 , wherein said heat radiation plate is rectangular in shape and said slits are fabricated to extend toward four corners of said heat radiation plate.  
     
     
         9 . A semiconductor device comprising: 
 a heat radiation plate including a main surface and a back surface opposite to said main surface, said heat radiation plate having slits penetrating from said main surface to said back surface;    a semiconductor chip having a semiconductor element and a plurality of electrodes furnished on a principal plane, said semiconductor chip being fastened to said main surface of said heat radiation plate;    a plurality of leads each having an inner lead and an outer lead, tips of the inner leads being fixed to said heat radiation plate, said inner leads being connected electrically to electrodes of said semiconductor chip; and    a molding member sealing said heat radiation plate, said semiconductor chip, and said inner leads;    wherein said slits are laid out in a radial direction radiating toward a region surrounded by said inner leads on said heat radiation plate.    
     
     
         10 . A semiconductor device according to  claim 9 , wherein said slits are fabricated so that said back of said semiconductor chip is partially exposed.  
     
     
         11 . A semiconductor device according to  claim 9 , wherein said slits are fabricated in such a manner that heat propagation paths are formed radially in said heat radiation plate.  
     
     
         12 . A semiconductor device according to  claim 9 , wherein said heat radiation plate is rectangular in shape and said slits are fabricated to extend toward four corners of said heat radiation plate.  
     
     
         13 . A semiconductor device according to  claim 9 , wherein pads of said electrodes are laid out in an alternately arrangement on said semiconductor chip.  
     
     
         14 . A semiconductor device according to  claim 9 , wherein said tips of said inner leads are laid out in an alternately arrangement.