Securing lids to semiconductor packages

Abstract

A bridge clip can provide off center loading between a lid and a semiconductor package during curing of adhesive for attachment of the lid to the integrated circuit die. This may be done, in some embodiments, without requiring an inventory of different parts and a variety of different assembly techniques by providing a leaf spring on the bridge clip which may be adapted for off center loading. The leaf spring may have its apex or centroid displaced with respect to the length of the bridge clip, transversely thereto or some combination thereof as needed. Thus, in some embodiments, a different leaf spring is all that needs to be provided to implement off center loading.

1 . A method comprising: 
 forming a bridge clip with a leaf spring offset with respect to the centroid of the bridge clip.    
   
   
       2 . The method of  claim 1  including offsetting said leaf spring along the length of said bridge clip.  
   
   
       3 . The method of  claim 1  including offsetting said leaf spring transversely to the length of said bridge clip.  
   
   
       4 . The method of  claim 1  including providing a leaf spring for a bridge clip that has a curved portion and a straight portion, the straight portion being longer on one side of said bridge clip than on the other side.  
   
   
       5 . The method of  claim 1  including providing a leaf spring having a curved portion and a pair of straight portions on opposed sides of said curved portion, said curved portion having an apex, said apex having an offset portion offset away from the centroid of said leaf spring.  
   
   
       6 . A method comprising: 
 using a bridge clip to provide off center loading between a die and a lid.    
   
   
       7 . The method of  claim 1  including providing a leaf spring having a curved portion to apply force to said lid, the apex of said curved portion being offset with respect to the centroid of said bridge clip.  
   
   
       8 . The method of  claim 7  including offsetting said leaf spring along the length of said bridge clip.  
   
   
       9 . The method of  claim 7  including offsetting said leaf spring transversely to the length of said bridge clip.  
   
   
       10 . The method of  claim 7  including providing a leaf spring for a bridge clip that has a curved portion and a straight portion, the straight portion being longer on one side of said bridge clip that on the other side.  
   
   
       11 . The method of  claim 7  including providing a leaf spring having a curved portion and a straight portion and a pair of straight portions on opposed sides of said curved portion, said curved portion having an apex, said apex being offset away from the centroid of said leaf spring.  
   
   
       12 . A bridge clip comprising: 
 a bridge;    a stiffener coupled to said bridge; and    a leaf spring mounted on said stiffener in an offset position.    
   
   
       13 . The bridge clip of  claim 12  wherein said leaf spring includes a curved portion and two opposed straight portions on either side of said curved portion, one of said straight portions being longer than the other of said straight portions.  
   
   
       14 . The bridge clip of  claim 12  wherein said leaf spring includes a curved portion and a pair of straight portions on opposite sides of said curved portion, said straight portions to engage said stiffener, said curved portion having an apex and a length, the apex of said curved portion being offset in a direction transverse to the length of said leaf spring.  
   
   
       15 . The bridge clip of  claim 12  including a pair of louvers in said stiffener, said louvers engaged by said leaf spring, said louvers being symmetrically positioned on said stiffener.  
   
   
       16 . A leaf spring for a bridge clip comprising: 
 a curved portion; and    two opposed straight portions on either side of said curved portion, one of said straight portions being longer than the other of said straight portions.    
   
   
       17 . The leaf spring of  claim 16  wherein said straight portions to fit into louvers in a bridge clip.  
   
   
       18 . A leaf spring for a bridge clip comprising: 
 a curved portion; and    a pair of straight portions on opposite sides of said curved portion, said straight portions to engage a stiffener, said curved portions including an apex and a length, the apex of said curved portions being offset in a direction transverse to the length of said leaf spring.    
   
   
       19 . The leaf spring of  claim 18  wherein the apex is indented on one side and includes an outwardly extending prong on the opposite side.