Methods for producing an electronic device having microscopically small contact areas

Abstract

A method for producing an electronic device, which has at least one microscopically small contact area for an electronic circuit having interconnects on a surface of a substrate. A three-dimensionally extending microscopically small contact element is integrally connected to the contact area in one piece.

1 . A method for producing an electronic device having microscopically small contact areas and interconnects formed on a surface of a substrate being one of a semiconductor chip and a semiconductor wafer, the contact areas having microscopically small contact elements respectively integrally connected to the contact areas in one piece and extending three-dimensionally at an oblique angle, the method which comprises: 
 patterning a conductive layer on a surface of a substrate to form interconnects and microscopically small contact areas;    applying a passivation layer to the patterned conductive layer;    opening contact windows in the passivation layer in order to uncover the contact areas;    applying a closed conductive layer in order to connect the contact areas;    applying a masking layer to the closed conductive layer;    patterning the masking layer with through openings that extend to the closed conductive layer near the contact areas;    filling the through openings with conductive material to form three-dimensionally extending microscopically small contact elements that are respectively integrally connected to the contact areas in one piece;    removing the masking layer; and    removing the closed conductive layer.    
     
     
         2 . The method according to  claim 1 , which comprises using photolithography methods to perform the steps of patterning the conductive layer and opening the contact windows in the passivation layer.  
     
     
         3 . The method according to  claim 1 , which comprises performing the step of applying the closed conductive layer using a technology selected from the group consisting of vapor-deposition technology, sputtering technology and deposition technology.  
     
     
         4 . The method according to  claim 1 , which comprises using a copper alloy layer as the closed conductive layer.  
     
     
         5 . The method according to  claim 1 , which comprises performing the step of applying the masking layer to the closed conductive layer using a process selected from the group consisting of spinning on, spraying on, and immersion.  
     
     
         6 . The method according to  claim 1 , which comprises using a photosensitive dielectric as the masking layer.  
     
     
         7 . The method according to  claim 6 , which comprises exposing the masking layer made of the photosensitive dielectric at a solid angle with respect to the contact areas in order to produce three-dimensionally angled contact elements.  
     
     
         8 . The method according to  claim 1 , which comprises using photolithography to perform the step patterning of the masking layer.  
     
     
         9 . The method according to  claim 1 , which comprises using a resin layer as the masking layer that is applied to the closed conductive layer.  
     
     
         10 . The method according to  claim 1 , which comprises using a process selected from the group consisting of laser removal technology, ion beam sputtering, and plasma etching to perform the step of patterning the masking layer with through openings.  
     
     
         11 . The method according to  claim 1 , which comprises using electro-deposition to perform the step of filling the through openings with conductive material.  
     
     
         12 . The method according to  claim 1 , which comprises using electroless deposition technology to perform the step of filling the through openings with conductive material.  
     
     
         13 . The method according to  claim 1 , which comprises using etching technology to perform the step of removing the closed conductive layer.  
     
     
         14 . The method according to  claim 1 , which comprises forming contact heads using a process selected from the group consisting of electrodeposition and an electroless process.  
     
     
         15 . The method according to  claim 1 , which comprises potting spaces between the contact elements.  
     
     
         16 . The method according to  claim 15 , which comprises performing the step of potting the spaces using a technology selected from the group consisting of spraying technology and injection-molding technology.  
     
     
         17 . The method according to  claim 1 , which comprises: 
 forming contact heads using a process selected from the group consisting of electrodeposition and an electroless process;    potting interspaces between the contact elements; and    uncovering the contact heads after performing the step of potting of the interspaces between the contact elements.    
     
     
         18 . The method according to  claim 17 , which comprises using laser removal technology to perform the step of uncovering the contact heads.  
     
     
         19 . The method according to  claim 1 , which comprises coating the contact heads with a metal selected from the group consisting of nickel and gold.  
     
     
         20 . A method for producing an electronic device having at least one microscopically small contact area, which comprises: 
 providing a substrate having a surface and a plurality of contact areas that are integrally connected to a plurality of three-dimensional microscopically small contact elements, the plurality of the contact areas being for at least one electronic circuit having interconnects located on the surface of the substrate;    patterning a metal sheet to produce a plurality of uncovered contact spring contours having breaking locations that are connected to the metal sheet and having uncovered ends which correspond in size, configuration and position to the plurality of the contact areas of the substrate;    aligning and pressing the patterned metal sheet onto the substrate so that the uncovered ends of the plurality of the contact spring contours are pressed onto the plurality of the contact areas;    heating the metal sheet and the substrate to bond the uncovered ends of the plurality of the contact spring contours to the plurality of the contact areas; and    cooling and stripping-off of the metal sheet, leaving behind three-dimensionally extending, bonded or soldered contact springs on each of the plurality of the contact areas.    
     
     
         21 . The method according to  claim 20 , which comprises, before pressing the metal sheet onto the substrate, coating the uncovered ends of the plurality of the contact spring contours with a layer that is selected from the group consisting of a nickel layer and a gold layer.  
     
     
         22 . The method according to  claim 20 , which comprises coating the plurality of the contact spring contours with a solderable metal alloy near the breaking locations.  
     
     
         23 . The method according to  claim 20 , which comprises: 
 providing a spring-elastic material having a thickness between 30 and 100 μm with a solderable tin layer; and then providing the material as the metal sheet that is patterned.    
     
     
         24 . The method according to  claim 20 , which comprises, before pressing the metal sheet onto the substrate, soft annealing regions of the plurality the contact spring contours.  
     
     
         25 . The method according to  claim 24 , wherein the regions are central regions of the plurality the contact spring contours.  
     
     
         26 . The method according to  claim 20 , which comprises: 
 using a soft metal sheet as the metal sheet that is patterned; and    after the metal sheet has been stripped off, heat-treating the three-dimensionally extending contact springs to obtain a desired spring property.    
     
     
         27 . The method according to  claim 20 , which comprises providing the metal sheet as a copper alloy metal sheet having patterns.