US2006082021A1PendingUtilityA1

Leadframe and method for reducing mold compound adhesion problems

45
Individually held — no corporate assignee on recordPriority: Oct 10, 2001Filed: Nov 30, 2005Published: Apr 20, 2006
Est. expiryOct 10, 2021(expired)· nominal 20-yr term from priority
Inventors:Vernon WilliamsMichael Gifford
H10W 74/016H10W 70/458H10W 70/457H10W 70/438H10W 70/048Y10T29/49146Y10T29/49121Y02P70/50
45
PatentIndex Score
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Cited by
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References
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Claims

Abstract

An integrated circuit leadframe has a pair of leadframe rails that are specially treated to adhere to injection mold compounds to a lesser or greater degree than portions of the leadframe rails outside of the treated areas. By adhering to mold compounds to a greater degree, mold compound not removed during a deflashing procedure does not flake off to form mold compound debris during a trimming and forming procedure. By adhering to mold compounds to a lesser degree, substantially all of the mold compound is removed during the deflashing procedure so there is no mold compound to flake off to form mold compound debris during the trimming and forming procedure. The leadframe rails may be treated by forming apertures in the rails, by increasing or decreasing the roughness of the leadframe rails, or by coating the leadframe rails with an adhesion promoting or reducing material.

Claims

exact text as granted — not AI-modified
1 - 60 . (canceled)  
   
   
       61 . A method of reducing the formation of mold compound flash debris during the packaging of an integrated circuit in which a leadframe is placed in a mold into which a mold compound is injected, and the leadframe is subsequently trimmed and formed, the method comprising treating a portion of the leadframe so that mold compound adheres to the treated area to a significantly different degree than the mold compound adheres to portions of the leadframe outside the treated area.  
   
   
       62 . The method of  claim 61  wherein the act of treating the portion of the leadframe so that mold compound adheres to the treated area to a significantly different degree than the mold compound adheres to portions of the leadframe outside the mold compound adherence area comprises treating the portion of the leadframe so that mold compound adheres to the treated area significantly more securely than the mold compound adheres to portions of the leadframe outside the mold compound adherence area.  
   
   
       63 . The method of  claim 61  wherein the act of treating the portion of the leadframe so that mold compound adheres to the treated area to a significantly different degree than the mold compound adheres to portions of the leadframe outside the mold compound adherence area comprises treating the portion of the leadframe so that mold compound adheres to the treated area significantly less securely than the mold compound adheres to portions of the leadframe outside the mold compound adherence area.  
   
   
       64 . The method of  claim 61  wherein the act of treating the portion of the leadframe so that mold compound adheres to the treated area to a significantly different degree than the mold compound adheres to portions of the leadframe outside the mold compound adherence area comprises treating respective areas on each leadframe rail of the leadframe so that mold compound adheres to the treated area to a significantly different degree than the mold compound adheres to portions of the leadframe outside the mold compound adherence area.  
   
   
       65 . The method of  claim 64  wherein the act of treating respective areas on each leadframe rail comprises treading opposite surfaces on each of the leadframe rails.  
   
   
       66 . The method of  claim 64  wherein the act of treating respective areas on each leadframe rail comprises forming at least one aperture in each of the leadframe rails.  
   
   
       67 . The method of  claim 66  wherein the act of forming at least one aperture in each of the leadframe rails comprises forming a plurality of apertures in each of the leadframe rails.  
   
   
       68 . The method of  claim 66  wherein the act of forming at least one aperture in each of the leadframe rails comprises forming an aperture having an elongated shape in each of the leadframe rails.  
   
   
       69 . The method of  claim 64  wherein the act of treating respective areas on each leadframe rail comprises forming an area of surface treatment on each of the leadframe rails.  
   
   
       70 . The method of  claim 69  wherein the act of forming an area of surface treatment on each of the leadframe rails comprises forming an area of increased surface roughness on each of the leadframe rails.  
   
   
       71 . The method of  claim 70  wherein the act of forming an area of increased surface roughness on each of the leadframe rails comprises mechanically forming an area of increased surface roughness on each of the leadframe rails.  
   
   
       72 . The method of  claim 70  wherein the act of forming an area of increased surface roughness on each of the leadframe rails comprises chemically forming an area of increased surface roughness on each of the leadframe rails.  
   
   
       73 . The method of  claim 70  wherein the act of forming an area of increased surface roughness on each of the leadframe rails comprises chemically forming an area of increased surface roughness on each of the leadframe rails.  
   
   
       74 . The method of  claim 69  wherein the act of forming an area of surface treatment on each of the leadframe rails comprises forming an area of a material on each of the leadframe rails that is different from a material used to form another portion of the leadframe.  
   
   
       75 . The method of  claim 64  wherein the act of treating respective areas on each leadframe rail comprises coating respective areas on each of the leadframe rails with a material that alters the adherence of the mold compound to the leadframe rails.  
   
   
       76 . The method of  claim 75  wherein the act of coating respective areas on each of the leadframe rails with a material that alters the adherence of the mold compound to the leadframe rails comprises coating respective areas on each of the leadframe rails with a material that increases the adherence of the mold compound to the leadframe rails.  
   
   
       77 . The method of  claim 75  wherein the act of coating respective areas on each of the leadframe rails with a material that alters the adherence of the mold compound to the leadframe rails comprises coating respective areas on each of the leadframe rails with a material that decreases the adherence of the mold compound to the leadframe rails.  
   
   
       78 . A method of packaging an integrated circuit, comprising: 
 treating a portion of a leadframe so that a mold compound adheres to the treated area to a significantly different degree than the mold compound adheres to portions of the leadframe outside the treated area;    mounting an integrated circuit on the leadframe;    placing the leadframe in a mold having a plurality of mold cavities;    injecting a mold compound into the mold cavities;    allowing the mold compound to solidify;    after the mold compound has solidified, removing the leadframe and a package formed by the mold compound from the mold as a unit; and    trimming and forming the leadframe.    
   
   
       79 . The method of  claim 78 , further comprising deflashing the leadframe after removing the leadframe and package from the mold and before the trimming and forming of the leadframe.  
   
   
       80 . The method of  claim 78  wherein the act of treating the portion of the leadframe so that mold compound adheres to the treated area to a significantly different degree than the mold compound adheres to portions of the leadframe outside the mold compound adherence area comprises treating the portion of the leadframe so that mold compound adheres to the treated area significantly more securely than the mold compound adheres to portions of the leadframe outside the mold compound adherence area.  
   
   
       81 . The method of  claim 78  wherein the act of treating the portion of the leadframe so that mold compound adheres to the treated area to a significantly different degree than the mold compound adheres to portions of the leadframe outside the mold compound adherence area comprises treating the portion of the leadframe so that mold compound adheres to the treated area significantly less securely than the mold compound adheres to portions of the leadframe outside the mold compound adherence area.  
   
   
       82 . The method of  claim 78  wherein the act of treating the portion of the leadframe so that mold compound adheres to the treated area to a significantly different degree than the mold compound adheres to portions of the leadframe outside the mold compound adherence area comprises treating respective areas on each leadframe rail of the leadframe so that mold compound adheres to the treated area to a significantly different degree than the mold compound adheres to portions of the leadframe outside the mold compound adherence area.  
   
   
       83 . The method of  claim 82  wherein the act of treating respective areas on each leadframe rail comprises treading opposite surfaces on each of the leadframe rails.  
   
   
       84 . The method of  claim 82  wherein the act of treating respective areas on each leadframe rail comprises forming at least one aperture in each of the leadframe rails.  
   
   
       85 . The method of  claim 84  wherein the act of forming at least one aperture in each of the leadframe rails comprises forming a plurality of apertures in each of the leadframe rails.  
   
   
       86 . The method of  claim 84  wherein the act of forming at least one aperture in each of the leadframe rails comprises forming an aperture having an elongated shape in each of the leadframe rails.  
   
   
       87 . The method of  claim 82  wherein the act of treating respective areas on each leadframe rail comprises forming an area of surface treatment on each of the leadframe rails.  
   
   
       88 . The method of  claim 87  wherein the act of forming an area of surface treatment on each of the leadframe rails comprises forming an area of increased surface roughness on each of the leadframe rails.  
   
   
       89 . The method of  claim 88  wherein the act of forming an area of increased surface roughness on each of the leadframe rails comprises mechanically forming an area of increased surface roughness on each of the leadframe rails.  
   
   
       90 . The method of  claim 88  wherein the act of forming an area of increased surface roughness on each of the leadframe rails comprises chemically forming an area of increased surface roughness on each of the leadframe rails.  
   
   
       91 . The method of  claim 88  wherein the act of forming an area of increased surface roughness on each of the leadframe rails comprises chemically forming an area of increased surface roughness on each of the leadframe rails.  
   
   
       92 . The method of  claim 87  wherein the act of forming an area of surface treatment on each of the leadframe rails comprises forming an area of a material on each of the leadframe rails that is different from a material used to form another portion of the leadframe.  
   
   
       93 . The method of  claim 82  wherein the act of treating respective areas on each leadframe rail comprises coating respective areas on each of the leadframe rails with a material that alters the adherence of the mold compound to the leadframe rails.  
   
   
       94 . The method of  claim 93  wherein the act of coating respective areas on each of the leadframe rails with a material that alters the adherence of the mold compound to the leadframe rails comprises coating respective areas on each of the leadframe rails with a material that increases the adherence of the mold compound to the leadframe rails.  
   
   
       95 . The method of  claim 93  wherein the act of coating respective areas on each of the leadframe rails with a material that alters the adherence of the mold compound to the leadframe rails comprises coating respective areas on each of the leadframe rails with a material that decreases the adherence of the mold compound to the leadframe rails.  
   
   
       96 . A method of packaging an integrated circuit, comprising: 
 mounting an integrated circuit on a leadframe, the leadframe having a pair of leadframe rails;    placing the leadframe in a mold having a plurality of mold cavities;    injecting a mold compound into the mold cavities;    allowing the mold compound to solidify;    after the mold compound has solidified, removing the leadframe and a package formed by the mold compound from the mold as a unit, the rails of the leadframe being at least partially coated with mold compound after being removed from the mold; and    trimming the leadframe while maintaining substantially all of the mold compound on the leadframe rails that was on the leadframe rails when the leadframe and package were removed from the mold.    
   
   
       97 . The method of  claim 96 , further comprising deflashing the leadframe after removing the leadframe and package from the mold and before the trimming the leadframe.  
   
   
       98 . The method of  claim 96  wherein the act of maintaining substantially all of the mold compound on the leadframe rails comprises, prior to the act of placing the leadframe in the mold, treating at least part of the leadframe rails so that the mold compound adheres to the treated area significantly more securely than the mold compound adheres to portions of the leadframe rails outside the treated area.  
   
   
       99 . A method of packaging an integrated circuit, comprising: 
 mounting an integrated circuit on a leadframe, the leadframe having a pair of leadframe rails;    placing the leadframe in a mold having a plurality of mold cavities;    injecting a mold compound into the mold cavities;    allowing the mold compound to solidify;    after the mold compound has solidified, removing the leadframe and a package formed by the mold compound from the mold as a unit, the rails of the leadframe being at least partially coated with mold compound after being removed from the mold; and    deflashing the leadframe after removing the leadframe and package from the mold, the act of deflashing removing substantially all of the mold compound from the leadframe rails; and    trimming the leadframe.    
   
   
       100 . The method of  claim 99  wherein the act of removing substantially all of the mold compound from the leadframe rails comprises, prior to the act of placing the leadframe in the mold, treating at least part of the leadframe rails so that the mold compound adheres to the treated area significantly less securely than the mold compound adheres to portions of the leadframe rails outside the treated area.

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