Protection circuit device using MOSFETs and a method of manufacturing the same

Abstract

A protection circuit device using a MOSFET has a plural of conductive paths separated electrically, a MOSFET chip integrating two power MOSFETs in one chip where a gate electrode and a source electrode are fixed on the desired conductive path, conductive material provided on a common drain electrode of the MOSFET, and insulating resin covering said MOSFET, and supporting said conductive path in one body. Removing a drawing-around of the common drain electrode and fixing the source electrode directly on the conductive path, low ON-state resistance is realized.

1 - 8 . (Canceled)  
     
     
         9 . A method for manufacturing a protection circuit device using MOSFETs comprising the steps of: 
 forming a trench on a surface of a conductive foil, except for a region to be a conductive path, a thickness of the trench is thinner than that of the conductive;    bonding each gate electrode and each source electrode of a MOSFET chip integrating two MOSFETs on said desired conductive path in one chip;    bonding conductive material on a common electrode of the MOSFET;    molding said MOSFET chip so as to be covered with insulating resin and to fill into said trench; and    removing said conductive foil of part of thickness where said trench is not provided.    
     
     
         10 . A method for manufacturing a protection circuit device using MOSFETs according to  claim 9 , wherein the step of forming a trench comprises the steps of: 
 forming an etching-tolerant conductive film on a region to be a conductive path on a surface of a conductive foil; and    forming the trench by using the etching-tolerant conductive film as a mask.    
     
     
         11 . A method for manufacturing a protection circuit device using MOSFETs according to  claim 9 , further comprising: 
 dividing into a plurality of devices by said insulating resin, wherein the devices comprises each of chip mounting portions.    
     
     
         12 . A method for manufacturing a protection circuit device using MOSFETs, further comprising the step of: 
 removing uniformly said conductive foil from a back face so that a back face of said conductive path and said insulating resin embedded between said trench, are substantially flat face.    
     
     
         13 . A method for manufacturing a protection circuit device using MOSFETs according to  claim 9 , comprising the steps of: 
 forming a conductive path having a lot of mounting portions by forming a thinner separated groove than thickness of said leading foil on at least said leading foil except area becoming the leading path;    bonding each gate electrode and each source electrode of a MOSFET chip integrating two MOSFETs on said desired conductive path of each mounting portion in one chip;    bonding conductive material on a common electrode of the MOSFET;    removing uniformly said conductive foil from a back face so that a back face of said conductive path and said insulating resin embedded between said trench, are substantially flat face; and    dividing into a plurality of devices by said insulating resin, wherein the devices comprises each of chip mounting portions.    
     
     
         14 . A method for manufacturing a protection circuit device using MOSFETs according to  claim 9 , wherein said conductive foil consists of any of copper, aluminum, iron-nickel.  
     
     
         15 . A method for manufacturing a protection circuit device using MOSFETs according to  claim 10 , characterized by that said conductive film is plated with any of nickel, gold and silver  
     
     
         16 . A method for manufacturing a protection circuit device using MOSFETs according to  claim 9 , wherein said trench formed selectively at said conductive foil is formed by chemical or physical etching.  
     
     
         17 . A method for manufacturing a protection circuit device using MOSFETs according to  claim 15 , wherein said conductive film is used as a part of a mask at forming said trench  
     
     
         18 . A method for manufacturing a protection circuit device using MOSFETs according to  claim 9 , wherein said conductive material is formed by a conductive metal plate or conductive brazing material.  
     
     
         19 . A method for manufacturing a protection circuit device using MOSFETs according to  claim 9 , wherein said insulating resin is a package formed by transfer mould.  
     
     
         20 . A method for manufacturing a protection circuit device using MOSFETs according to  claim 11 , wherein said dividing step comprises a step of forming notches having a predetermined depth by using a dicing saw and dividing into each of the chip mounting areas.