Method and composition for mounting an electronic component and device formed therewith

Abstract

A method of mounting a component on a substrate includes applying a conductive adhesive on a contact pad joined to a substrate, aligning a component with the substrate such that at least one lead of the component is juxtaposed with the conductive adhesive, performing a partial cure of the conductive adhesive, testing performance of the component, and performing a full cure of the conductive adhesive. Another method includes the additional steps of applying a tacky film to the substrate and juxtaposing the component with the tacky film. When the testing in either embodiment shows a defective or misaligned component, the component may be replaced or repositioned by cold separation of the at least one component lead from the partially cured conductive adhesive. Optionally, additional conductive adhesive may be applied, when needed, before replacement or repositioning of a component. A composition for mounting a component on a circuit board includes a conductive adhesive screened on a contact pad, the conductive adhesive being partially cured, wherein the composition allows cold separation of the component from the substrate and may be fully cured by heat exposure. An apparatus is also provided including a component, a substrate, and a means for temporarily mounting and electrically connecting the component on the substrate.

1 . A method for mounting a component on a substrate comprising the steps of: 
 a) applying a conductive adhesive on a contact pad joined to a substrate;    b) aligning a component with the substrate such that at least one lead of the component is juxtaposed with the conductive adhesive;    c) performing a partial cure of the conductive adhesive, such that an electrical and mechanical connection suitable for testing is formed;    d) testing the component; and    e) performing a full cure of the conductive adhesive, such that a permanent connection is formed.    
     
     
         2 . The method of  claim 1 , wherein the method additionally comprises the step of applying a tacky film to the substrate and wherein the step of aligning the component with the substrate additionally comprises juxtaposing the component with the tacky film.  
     
     
         3 . The method of  claim 1 , wherein the step of performing a partial cure comprises heat curing the conductive adhesive at 50 to 105° C. for 1 hour to 10 minutes.  
     
     
         4 . The method of  claim 1 , wherein the step of performing a full cure comprises heat curing the conductive adhesive at 50 to 200° C. for 12 hours to 15 seconds.  
     
     
         5 . The method of  claim 1 , additionally comprising the step of replacing the component, if defective, with a new component and the step of adjusting the position of or repositioning the component, if misaligned, wherein the replacing and repositioning include cold separation of the at least one component lead from the partially cured conductive adhesive.  
     
     
         6 . The method of  claim 2 , wherein the tacky film is selected from the group consisting essentially of pressure sensitive tape, silicon-based adhesive tape, acrylic-based adhesive tape, partially cured polymer resin, thermoset or thermoplastic adhesive, and pressure sensitive, thermoset, or thermoplastic preform films.  
     
     
         7 . The method of  claim 4 , wherein the step of performing a full cure comprises heat curing the conductive adhesive at 125 to 150° C. for approximately 1.5 hours.  
     
     
         8 . The method of  claim 5 , wherein additional conductive adhesive is applied on the contact pad before replacing the new component on the substrate and before repositioning the misaligned component to its correct position.  
     
     
         9 . A method for mounting a component on a substrate comprising the steps of: 
 a) applying a conductive adhesive on a contact pad joined to a substrate;    b) applying a tacky film to the substrate;    c) aligning a component with the substrate such that the component is juxtaposed with the tacky film and at least one lead of the component is juxtaposed with the conductive adhesive;    d) performing a partial cure of the conductive adhesive, such that an electrical and mechanical connection suitable for testing is formed;    e) testing the component; and    f) performing a full cure of the conductive adhesive, such that a permanent connection is formed.    
     
     
         10 . The method of  claim 9 , wherein the step of performing a partial cure comprises heat curing the conductive adhesive at 50 to 105° C. for 1 hour to 10 minutes.  
     
     
         11 . The method of  claim 9 , wherein the step of performing a full cure comprises heat curing the conductive adhesive at 50 to 200° C. for 12 hours to 15 seconds.  
     
     
         12 . The method of  claim 9 , additionally comprising the step of replacing the component, if defective, with a new component and the step of adjusting the position of or repositioning the component, if misaligned, wherein the replacing and repositioning include cold separation of the component from the tacky film and the at least one component lead from the partially cured conductive adhesive.  
     
     
         13 . The method of  claim 9 , wherein the tacky film is selected from the group consisting essentially of pressure sensitive tape, silicon-based adhesive tape, acrylic-based adhesive tape, partially cured polymer resin, thermoset or thermoplastic adhesive, and pressure sensitive, thermoset, or thermoplastic preform films.  
     
     
         14 . The method of  claim 11 , wherein the step of performing a full cure comprises heat curing the conductive adhesive at 125 to 150° C. for approximately 1.5 hours.  
     
     
         15 . The method of  claim 12 , wherein additional conductive adhesive is applied on the contact pad before replacing the new component on the substrate and before repositioning the misaligned component to its correct position.  
     
     
         16 . A composition for mounting a component on a substrate comprising a conductive adhesive applied on a contact pad, the conductive adhesive being partially cured, wherein the composition allows cold separation of the component from the substrate and may selectively be fully cured to permanently mount the component.  
     
     
         17 . The composition of  claim 16 , wherein the conductive adhesive may be fully cured by heat exposure.  
     
     
         18 . The composition of  claim 16 , wherein the conductive adhesive may be partially cured by heat exposure.  
     
     
         19 . The composition of  claim 16 , wherein the composition also allows cold remounting of a separated component on the substrate.  
     
     
         20 . An apparatus comprising: 
 a) a component;    b) a substrate; and    b) a means for temporarily mounting and electrically connecting the component on the substrate.    
     
     
         21 . The apparatus of  claim 20 , wherein the component is selected from the group consisting of a ball-grid array (BGA), a flip-chip, components with array-type connections, a quad flat package (QFP), a J-lead component, components suitable for tape automated bonding (TAB), and components with peripheral-type connections.  
     
     
         22 . The apparatus of  claim 20 , wherein the means for temporarily mounting and electrically connecting the component is also a means for selectively mounting the component permanently on the substrate.  
     
     
         23 . The apparatus of  claim 22 , wherein the means for temporarily mounting and electrically connecting the component and selectively mounting the component permanently on the substrate comprise a conductive adhesive applied on a contact pad, the conductive adhesive being partially cured, wherein the conductive adhesive allows cold separation of the component from the substrate and may be fully cured.  
     
     
         24 . The apparatus of  claim 23 , wherein the conductive adhesive is partially and fully cured by heat exposure.  
     
     
         25 . The apparatus of  claim 23 , wherein the means for temporarily mounting and electrically connecting the component and selectively mounting the component permanently on the substrate comprise, in combination, a conductive adhesive applied on a contact pad, the conductive adhesive being partially cured, and a tacky film applied to the substrate, wherein the conductive adhesive and tacky film allow cold separation of the component from the substrate and the conductive adhesive may be fully cured by heat exposure.