US2006197233A1PendingUtilityA1

Die attach material for TBGA or flexible circuitry

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Assignee: JIANG TONGBIPriority: Dec 21, 1999Filed: May 2, 2006Published: Sep 7, 2006
Est. expiryDec 21, 2019(expired)· nominal 20-yr term from priority
Inventors:Tongbi Jiang
H10W 72/922H10W 72/29H10W 70/60H10W 72/983H10W 72/07633H10W 72/07338H10W 72/07336H10W 72/354H10W 72/352H10W 72/07251H10W 72/251H10W 72/20H10W 72/244H10W 72/652H10W 72/655H10W 72/90H10W 76/40H10W 74/129H10W 70/688
48
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Claims

Abstract

An attachment material is provided between the die and the solder balls of a TBGA or other flexible circuitry package that is sufficiently compliant to absorb pressure between the two, so as not to apply stress to the solder balls. The attachment material is also sufficiently rigid, with a low coefficient of thermal expansion (CTE), so that the material does not excessively expand and contract during thermal cycling relative to the die. More preferably, the attachment material has a CTE close to that of the die to prevent breakage of the tape at the junction between the tape and the die.

Claims

exact text as granted — not AI-modified
1 . A method of preventing breakage of a flexible tape bonded to a chip and connected to an array of solder balls, comprising: 
 providing a compliant material between the chip and array of solder balls, the material having a coefficient of thermal expansion of less than about 200 ppm/° C. and a modulus of elasticity greater than about 100 ksi.    
   
   
       2 . The method of  claim 1 , wherein the modulus of elasticity is less than about 126 ksi.  
   
   
       3 . The method of  claim 1 , wherein the coefficient of thermal expansion is less than about 150 ppm/° C.  
   
   
       4 . The method of  claim 3 , wherein the modulus of elasticity is less than about 126 ksi.  
   
   
       5 . The method of  claim 3 , wherein the coefficient of thermal expansion is less than about 106 ppm/° C.  
   
   
       6 . The method of  claim 5 , wherein the modulus of elasticity is less than about 126 ksi.  
   
   
       7 . The method of  claim 5 , wherein the coefficient of thermal expansion is less than about 100 ppm/° C.  
   
   
       8 . The method of  claim 7 , wherein the modulus of elasticity is less than about 126 ksi.  
   
   
       9 . A method of preventing breakage of a flexible tape bonded to a chip and connected to an array of solder balls, comprising: 
 providing a compliant material between the chip and array of solder balls, the material having a coefficient of thermal expansion of less than about 100 ppm/° C. and a modulus of elasticity greater than about 10 ksi.    
   
   
       10 . The method of  claim 9 , wherein the modulus of elasticity is greater than about 50 ksi.  
   
   
       11 . The method of  claim 9 , wherein the modulus of elasticity is greater than about 100 ksi.

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