Method of wafer bumping for enabling a stitch wire bond in the absence of discrete bump formation, and method of forming semiconductor device assembly including same

Abstract

A method of bumping a wafer for facilitating bonding of bond wires to elevate the bond location above the passivation layer. The wafer is bumped by disposing the wafer in at least one electroless bath having a nickel-containing solution therein, wherein bumps having a nickel-containing material are formed simultaneously on the exposed bond pads to an elevation sufficient to prevent damage to a passivation layer surrounding the bond pads by contact of a wire bonding capillary. A gold or palladium cap may optionally be formed over the nickel-containing material of the bumps. A method of forming a semiconductor device assembly is also disclosed.

What is claimed is:  
     
         1 . A method of bumping wafers, comprising: 
 providing at least one wafer having an active surface and a back surface, the active surface having bond pads exposed thereon through a passivation layer; and    disposing the at least one wafer in at least one bath including a nickel material to form a nickel-containing bump on each of the exposed bond pads.    
     
     
         2 . The method of  claim 1 , wherein disposing comprises disposing the at least one wafer in at least one of an electroless bath and an electrolytic bath.  
     
     
         3 . The method of  claim 1 , wherein disposing comprises disposing multiple wafers simultaneously in the at least one bath.  
     
     
         4 . The method of  claim 1 , further comprising disposing the at least one wafer in at least another bath including a gold material to form a gold-containing cap over each of the nickel-containing bumps.  
     
     
         5 . The method of  claim 1 , further comprising disposing the at least one wafer in at least another bath including a palladium material to form a palladium-containing cap over each of the nickel-containing bumps.  
     
     
         6 . The method of  claim 1 , wherein disposing comprises forming the nickel-containing bumps with an outer surface thereof displaced above an outer surface of the passivation layer.  
     
     
         7 . The method of  claim 1 , wherein disposing comprises forming the nickel-containing bumps with an outer surface thereof substantially coplanar with an outer surface of the passivation layer.  
     
     
         8 . The method of  claim 1 , wherein forming comprises forming the nickel-containing bumps with an outer surface thereof displaced above an outer surface of the passivation layer approximately 0.2 microns to 2.5 microns.  
     
     
         9 . A method of forming a semiconductor device assembly, the method comprising: 
 providing at least one semiconductor die having an active surface with bond pads formed thereon and a back surface, the bond pads being exposed through a passivation layer and each of the bond pads including a nickel-containing bump formed thereon;    providing a carrier substrate having conductive portions exposed on a surface thereof; and    attaching the at least one semiconductor die to the surface of the carrier substrate in a location and orientation exposing the nickel-containing bumps on the bond pads; and    bonding bond wires to the nickel-containing bumps on the active surface and to the conductive portions of the carrier substrate without contacting the passivation layer with a wire bond capillary.    
     
     
         10 . The method of  claim 9 , wherein providing the at least one semiconductor die comprises forming each of the nickel-containing bumps with an outer surface thereof displaced above an outer surface of the passivation layer.  
     
     
         11 . The method of  claim 9 , wherein providing the at least one semiconductor die comprises forming each of the nickel-containing bumps with an outer surface thereof substantially coplanar with an outer surface of the passivation layer.  
     
     
         12 . The method of  claim 9 , wherein providing the at least one semiconductor die comprises forming each of the nickel-containing bumps with an outer surface thereof displaced above an outer surface of the passivation layer approximately 0.2 microns to 2.5 microns.  
     
     
         13 . The method of  claim 9 , wherein providing the at least one semiconductor die comprises providing the at least one semiconductor die with at least some of the nickel-containing bumps proximate a periphery of the active surface thereof.  
     
     
         14 . The method of  claim 13 , wherein attaching comprises attaching the back surface of the at least one semiconductor die to the surface of the carrier substrate.  
     
     
         15 . The method of  claim 9 , wherein providing the at least one semiconductor die comprises providing the at least one semiconductor die with at least some of the nickel-containing bumps centrally aligned on the active surface thereof.  
     
     
         16 . The method of  claim 15 , wherein providing the carrier substrate comprises providing the carrier substrate with a slot defined therein, wherein the slot extends between the surface of the carrier substrate and an opposing, second surface of the carrier substrate, and wherein attaching comprises attaching the active surface of the at least one semiconductor die to the second surface of the carrier substrate so that the nickel-containing bumps are exposed through the slot.  
     
     
         17 . The method of  claim 9 , further comprising encapsulating at least the nickel-containing bumps and the bond wires with a dielectric encapsulant.  
     
     
         18 . A method of preparing wafers for bonding bond wires thereto, the method comprising: 
 providing at least one wafer having an active surface and a back surface, the active surface having bond pads exposed thereon through a passivation layer;    disposing the at least one wafer in at least one bath including a nickel material to form nickel-containing bumps on each of the exposed bond pads.    
     
     
         19 . The method of  claim 18 , further comprising cleaning the nickel-containing bumps.  
     
     
         20 . The method of  claim 19 , wherein cleaning comprises performing an argon plasma cleaning.  
     
     
         21 . The method of  claim 18 , wherein disposing comprises disposing the at least one wafer in at least one of an electroless bath and an electrolytic bath.  
     
     
         22 . The method of  claim 21 , wherein disposing comprises disposing a plurality of wafers simultaneously.  
     
     
         23 . The method of  claim 18 , further comprising disposing the at least one wafer in at leat another bath including a gold material to form a gold-containing cap over each of the nickel-containing bumps.  
     
     
         24 . The method of  claim 18 , further comprising disposing the at least one wafer in at least another bath including a palladium material to form a palladium-containing cap over each of the nickel-containing bumps.  
     
     
         25 . The method of  claim 18 , wherein disposing comprises forming the nickel-containing bumps with an outer surface thereof displaced above an outer surface of the passivation layer.  
     
     
         26 . The method of  claim 18 , wherein disposing comprises forming the nickel-containing bumps with an outer surface thereof substantially coplanar with an outer surface of the passivation layer.  
     
     
         27 . The method of  claim 18 , wherein disposing comprises forming the nickel-containing bumps with an outer surface thereof displaced above the outer surface of the passivation layer approximately 0.2 microns to 2.5 microns.