Production methods for a leadframe and electronic devices

Abstract

A leadframe for semiconductor chips and electronic devices produced on the leadframe includes providing the leadframe with a basic substrate, on which are disposed external contact elements exhibiting a rivet-shaped cross-section with a rivet head region, a rivet shank region, and a rivet foot region, as a result of which, the external contact elements are securely anchored in the housing made of a plastics compound.

1 . A method for producing a leadframe for packaging semiconductor chips to form electronic devices in housings of a plastics compound, which comprises: 
 providing a basic substrate with an electrically conductive surface;    applying on the basic substrate a patterned electrically insulating layer having uncovered electrically conductive surface regions in a contact element configuration;    applying a conductive material to form external contact elements in the contact element configuration, the external contact elements having a rivet-shaped cross-section with a rivet head region, a rivet shank region, and a rivet foot region, the rivet foot region being fixed on the basic substrate; and    removing the patterned electrically insulating layer.    
     
     
         2 . The method according to  claim 1 , which further comprises carrying out the insulating layer application step by applying the patterned electrically insulating layer on the electrically conductive surface.  
     
     
         3 . The method according to  claim 1 , which further comprises carrying out the insulating layer application step by first applying a closed insulating layer and then patterning the closed insulating layer by photoresist technology to form the patterned electrically insulating layer.  
     
     
         4 . The method according to  claim 1 , which further comprises carrying out the insulating layer application step by applying the patterned electrically insulating layer by a screenprinting process.  
     
     
         5 . The method according to  claim 1 , which further comprises applying a patterned electrically conductive layer by a screenprinting process.  
     
     
         6 . The method according to  claim 1 , which further comprises carrying out the insulating layer application step by sputtering a patterning of an initially closed insulating layer onto the basic substrate through a mask.  
     
     
         7 . The method according to  claim 1 , which further comprises carrying out the insulating layer application step by vapor phase depositing an initially closed insulating layer to the basic substrate.  
     
     
         8 . The method according to  claim 1 , which further comprises carrying out the insulating layer application step by plasma etching a patterning of an initially closed insulating layer through a mask.  
     
     
         9 . The method according to  claim 1 , which further comprises carrying out the insulating layer application step by laser raster irradiating a patterning of an initially closed insulating layer.  
     
     
         10 . The method according to  claim 1 , which further comprises carrying out the conductive material application step by electrodepositing the conductive material on the uncovered electrically conductive surface regions until overgrowth of the deposited material forms a rivet head.  
     
     
         11 . The method according to  claim 1 , which further comprises carrying out the conductive material application step by vapor phase depositing a metal.  
     
     
         12 . The method according to  claim 1 , which further comprises carrying out the conductive material application step by currentlessly electrodepositing the conductive material.  
     
     
         13 . The method according to  claim 1 , which further comprises forming a metallic base in a chip carrier region of the basic substrate at the same time the external contact elements are formed.  
     
     
         14 . A method for producing an electronic device, which comprises: 
 providing a leadframe having: 
 a basic substrate; and  
 external contact elements having a rivet-shaped cross-section with a rivet head region, a rivet shank region, and a rivet foot region, the rivet foot region being fixed on the basic substrate;  
   applying semiconductor chips to the leadframe, the semiconductor chips having contact areas;    producing connections between the contact areas and the external contact elements;    potting the leadframe having the applied semiconductor chips and the connections with a plastics compound to form electronic devices with a housing of the plastics compound, the external contact elements being anchored with the rivet head region in the plastics compound; and    singulating the electronic devices produced on the leadframe.    
     
     
         15 . The method according to  claim 14 , which further comprises, during potting, potting the leadframe, for a multiplicity of discrete electronic devices, with a uniform thickness of the plastics compound substantially over an entire expanse of the leadframe to form a plastic plate having the basic substrate on one side of the plastic plate.  
     
     
         16 . The method according to  claim 15 , which further comprises, etching away the basic substrate from the plastic plate before carrying out the singulating step.  
     
     
         17 . The method according to  claim 15 , which further comprises coating the plastic plate with an adhesive film before singulation.  
     
     
         18 . The method according to  claim 16 , which further comprises coating the plastic plate with an adhesive film before singulation.  
     
     
         19 . The method according to  claim 15 , which further comprises carrying out the singulating step by sawing the plastic plate to form discrete electronic devices.  
     
     
         20 . The method according to  claim 14 , which further comprises producing the connections between the contact areas and the external contact elements by bonding bumps onto the rivet head regions of the external contact elements and flip-chip mounting the leadframe and the semiconductor chips through the bumps.  
     
     
         21 . The method according to  claim 14 , which further comprises producing the connections between the contact areas and the external contact elements by flip-chip technology utilizing bonding bumps bonded onto the rivet head regions of the external contact elements.  
     
     
         22 . The method according to  claim 14 , which further comprises producing the connections between contact areas of the semiconductor chip and the external contact elements by connecting the contact areas of the semiconductor chip to the rivet head regions of the external contact elements with bonding wires.  
     
     
         23 . The method according to  claim 14 , which further comprises one of soldering and adhesively bonding the semiconductor chips onto a metallic base during application of semiconductor chips to the leadframe.  
     
     
         24 . The method according to  claim 14 , wherein the basic substrate is a carbon-coated film, and which further comprises stripping the film away from the electronic devices during the singulation of the electronic devices.  
     
     
         25 . The method according to  claim 24 , which further comprises removing a carbon layer from the electronic devices by plasma incineration after stripping away the film.  
     
     
         26 . The method according to  claim 14 , wherein the basic substrate is a metal-coated plastic film and which further comprises, during the singulation of the electronic devices: 
 stripping away the plastic film of the metal-coated plastic film; and    removing the metallic coating of the metal-coated plastic film by one of wet-chemical etching and dry etching.    
     
     
         27 . The method according to  claim 14 , wherein the basic substrate is a metallic foil and which further comprises, during the singulation of the electronic devices, completely removing the metallic foil by one of wet etching and dry etching until an etching stop is reached between the material of the external contact elements and the metallic material of the basic substrate.