Flip chip interconnect solder mask

Abstract

A solder mask for flip chip interconnection has a common opening that spans a plurality of circuit elements. The solder mask allows confinement of the solder during the remelt stage of interconnection, yet it is within common design rules for solder mask patterning. Also, a substrate for flip chip interconnection includes a substrate having the common opening that spans a plurality of circuit elements. Also, a flip chip package includes a substrate having a common opening that spans a plurality of circuit elements.

1 . A solder mask for flip chip interconnection having a common opening that spans a plurality of circuit elements.  
   
   
       2 . A flip-chip package substrate, comprising a patterned metal layer on a die attach side of a dielectric substrate layer, the metal layer including interconnect sites, the substrate including a solder mask having an opening spanning a plurality of the interconnect sites.  
   
   
       3 . The substrate of  claim 2  wherein the plurality of interconnect sites comprises interconnect sites arranged in a row, and the opening comprises a elongate opening spanning the row.  
   
   
       4 . The substrate of  claim 2  wherein the opening has an irregular shape.  
   
   
       5 . The substrate of  claim 2  wherein the interconnect sites are arranged in an array of rows, and the opening comprises an elongate opening spanning one of the rows of interconnect sites.  
   
   
       6 . A method for making a flip chip interconnection, comprising providing a substrate including a solder mask having an opening spanning a plurality of the interconnect sites, and mounting the chip onto the substrate.