Interposer substrates with multi-segment interconnect slots, semiconductor die packages including same, semiconductor dice for use therewith and methods of fabrication

Abstract

A board-on-chip (BOC) semiconductor package includes a multisegmented, longitudinally slotted interposer substrate through which an elongate row of die bond pads is accessed for electrical attachment, as by wire bonding, to conductive traces on the opposite side of the interposer substrate. One or more reinforcements in the form of crosspieces or bridges span and segment intermediate portions of the substrate slot to resist bending stresses acting in the slot region proximate the centerline of the interposer substrate tending to crack or delaminate a polymer wire bond mold cap filling and covering the slot and the wire bonds. Various interposer substrate configurations are also disclosed, as are methods of fabrication.

1 . A method for forming an interposer substrate, comprising: 
 providing a substantially planar substrate;    forming an elongated interconnect slot comprising a plurality of longitudinally adjacent segments separated by at least one transversely extending crosspiece.    
     
     
         2 . The method of  claim 1 , further comprising forming the interconnect slot by milling through the substrate and the at least one transversely extending crosspiece comprises at least one unmilled portion of the substrate lying intermediate opposing ends of the interconnect slot.  
     
     
         3 . The method of  claim 2 , further comprising producing filleted side edges on the at least one transversely extending crosspiece during the milling.  
     
     
         4 . The method of  claim 1 , wherein forming the elongated interconnect slot comprises forming a unitary elongated interconnect slot and forming the at least one transversely extending crosspiece by bonding a segment of material transversely across the interconnect slot at a location intermediate opposing ends thereof.  
     
     
         5 . The method of  claim 4 , wherein forming the at least one transversely extending crosspiece comprises forming a tape segment coated with an adhesive on opposing sides thereof and adhering the tape segment to a surface of the substantially planar substrate.  
     
     
         6 . The method of  claim 1 , wherein forming the elongated interconnect slot comprises forming a unitary elongated interconnect slot, forming an “I”-shaped segment of material and bonding a head portion of the “I”-shaped segment to the substrate on one side of the interconnect slot and a foot portion of the “I”-shaped segment to the substrate on an opposing side of the interconnect slot with a body portion of the “I”-shaped segment extending transversely thereacross to form the at least one transversely extending crosspiece.  
     
     
         7 . The method of  claim 6 , further comprising forming the “I”-shaped segment as a film having an adhesive coating on opposing sides thereof.  
     
     
         8 . The method of  claim 6 , further comprising forming the “I”-shaped segment as a substantially rigid plastic segment.  
     
     
         9 . The method of  claim 1 , wherein forming the elongated interconnect slot comprises forming a unitary elongated interconnect slot, forming a “T”-shaped element having a body and a cap, extending the body into the interconnect slot in contact with opposing sides thereof and bonding legs of the cap extending transversely to the interconnect slot over a surface of the substrate thereto to form the at least one transversely extending crosspiece.  
     
     
         10 . The method of  claim 1 , wherein forming the elongated interconnect slot comprises forming a unitary elongated interconnect slot, forming a tape segment of a polymeric material containing a reinforcement material, disposing the tape segment transversely across the interconnect slot and bonding the tape segment to a surface of the substrate.  
     
     
         11 . The method of  claim 1 , wherein forming the elongated interconnect slot comprises forming a unitary elongated interconnect slot, interposing a bar of material transversely between opposing sides of the interconnect slot and bonding the bar thereto.  
     
     
         12 . The method of  claim 1 , further comprising forming the elongated interconnect slot to a length of about 67% or more of a length of the substrate.  
     
     
         13 . The method of  claim 12 , further comprising forming the elongated interconnect slot to a length of about 70 to 80% of a length of the substrate.  
     
     
         14 . The method of  claim 1 , further comprising locating the at least one transversely extending crosspiece substantially at a longitudinal midpoint of the interconnect slot.