Leadframe with pad anchoring members and method of forming the same

Abstract

A leadframe having extensions around an outer edge of a die pad are disclosed. More specifically, leadframes are created with a flange formed at the outer edge of the die pad and extending away from the die pad. The flange is bent, such that it is positioned at an angle with respect to the die pad. Leadframes are also created with anchoring posts formed adjacent the outer edge of the die pad and extending away from the die pad. The anchoring posts have a central thickness that is less than a thickness of first and second portions opposite the central portion. When the leadframe is incorporated into a package, molding compound completely surrounds each flange or anchoring post, which increases the bond strength between the leadframe and the molding compound due to increased contact area. The net result is a reduced possibility of delamination at edges of the die pad.

1 . A method, comprising:
 forming a die pad of a leadframe; and   forming a plurality of first flanges along a first edge of the die pad, forming the plurality of first flanges including:
 spacing adjacent ones of the plurality of first flanges from each other separating each respective first flange of the plurality of first flanges from each other. 
   
     
     
         2 . The method of  claim 1 , further comprising:
 forming a plurality of second flanges at a second edge of the die pad opposite to the first edge, forming the plurality of second flanges including:
 spacing adjacent ones of the plurality of second flanges from each other separating each respective second flange of the plurality of second flanges from each other. 
   
     
     
         3 . The method of  claim 2 , wherein:
 separating each of the respective first flanges of the plurality of first flanges further includes forming respective first indentations of a plurality of first indentations between adjacent ones of the plurality of first flanges; and   separating each of the respective second flanges of the plurality of second flanges further include forming respective second indentations of a plurality of second indentations between adjacent ones of the plurality of second flanges.   
     
     
         4 . The method of  claim 1 , further comprising:
 forming a plurality of second flanges at a second edge of the die pad transverse to the first edge of the die pad, forming the plurality of second flanges including:
 spacing adjacent ones of the plurality of second flanges from each other separating each respective second flange of the plurality of second flanges from each other. 
   
     
     
         5 . The method of  claim 1 , wherein separating each of the respective first flanges of the plurality of first flanges further includes forming respective first indentations of a plurality of first indentations between adjacent ones of the plurality of first flanges. 
     
     
         6 . A method, comprising:
 forming a die pad with a first thickness by removing a first portion from the leadframe at and along the first surface of the lead frame;   forming a plurality of flanges with a second thickness greater than the first thickness and at one or more outermost edges of the die pad by removing one or more second portions spaced apart from the first portion of the leadframe at and along a first surface of the leadframe and spaced outward from a center of the die pad; and   forming one or more leads of the leadframe by removing one or more third portions from the leadframe at and along a second surface of the leadframe opposite to the first surface of the leadframe.   
     
     
         7 . The method of  claim 6 , wherein forming the die pad and the plurality of flanges further includes:
 forming one or more first flanges of the plurality of flanges at a first outermost edge of the one or more outermost edges of the die pad; and   forming one or more second flanges of the plurality of flanges at a second outermost edge of the one or more outermost edges of the die pad.   
     
     
         8 . The method of  claim 7 , wherein:
 forming the one or more first flanges includes forming only one first flange that extends a majority of the first outermost edge of the one or more outermost edges of the die pad; and   forming the one or more second flanges includes forming only one second flange that extends a majority of the second outermost edge of the one or more outermost edges of the die pad.   
     
     
         9 . The method of  claim 7 , wherein:
 forming the one or more first flanges includes forming a plurality of first flanges that are separate and distinct from each other and spaced apart from each other; and   forming the one or more second flanges includes forming a plurality of second flanges that are separate and distinct from each other and spaced apart from each other.   
     
     
         10 . The method of  claim 6 , wherein respective third portions of the one or more third portions of leadframe are aligned with and overlapped by the respective second portions of the one or more second portions of the leadframe. 
     
     
         11 . The method of  claim 6 , further comprising positioning one or more end surfaces of the plurality of flanges at an angle transverse to a mounting surface of the die pad by bending the leadframe. 
     
     
         12 . The method of  claim 11 , wherein the angel is equal to 90 degrees. 
     
     
         13 . The method of  claim 11 , wherein the angle is less than 90 degrees. 
     
     
         14 . The method of  claim 11 , wherein the angle is less than or equal to 90 degrees. 
     
     
         15 . The method of  claim 11 , wherein bending the leadframe includes bending the leadframe at a peripheral region around the mounting surface of the die pad. 
     
     
         16 . The method of  claim 6 , wherein forming the die pad and the forming the plurality of flanges occurs simultaneously. 
     
     
         17 . The method of  claim 6 , further comprising:
 coupling a die to a mounting surface of the die pad;   forming one or more bonding wires coupling the die to the one or more leads;   forming a molding compound on the die, the one or more bonding wires, the die pad, the plurality of flanges, and the one or more leads.   
     
     
         18 . A device, comprising:
 a leadframe including:
 a first surface; 
 a second surface opposite to the first surface; 
 a die pad including:
 a mounting region along the first surface 
 a peripheral region extending around the mounting region; and 
 a first thickness that extends from the first surface to the second surface; 
 
 a plurality of flanges at the plurality of outermost regions of the die pad, each respective flange of the plurality of flanges includes an end surface, and each respective flange of the plurality of flanges includes a second thickness that extends from first surface to the corresponding end surface of the end surfaces of the plurality of flanges. 
   
     
     
         19 . The device of  claim 18 , wherein the end surfaces of the plurality of flanges are substantially parallel with the first surface and the second surface of the die pad. 
     
     
         20 . The device of  claim 18 , wherein:
 the die pad includes a first outmost region and a second outmost region opposite to the first outermost region about the mounting region; and   the plurality of flanges includes:
 a first flange at the first outermost region, the first flange extends a majority of the first outermost region; and 
 a second flange at the second outermost region, the second flange extends a majority of the second outermost region.