Semiconductor assembly having substrate with electroplated contact pads

A semiconductor assembly comprising:

• a semiconductor chip having an active circuit and at least one metallization layer thereover;
• an electrically conductive bonding surface positioned directly over said metallization layer;
• said bonding surface having connector stacks to said metallization layer, each of said stacks comprising a seed metal layer in contact with said metallization layer capable of providing an adhesive and conductive layer for electroplating on its surface, an electroplated support layer secured to said seed metal layer, and at least one sacrificial metal layer on said support layer so that each stack defines a chip bond pad;
• a reflow metal connection element attached to each of said chip bond pads;
• an insulating substrate having first and second surfaces and a plurality of metal-filled vias extending from said first to said second surface;
• said first substrate surface having contact pads in matching position to said chip bond pads, each contact pad comprising a connector stack to at least one of said vias, each of said stacks comprising a seed metal layer in contact with said via metal capable of providing an adhesive and conductive layer for electroplating on its surface, a first electroplated support metal layer secured to said seed metal layer, a second electroplated support metal layer on said first support layer, and at least one sacrificial metal layer on said second support layer, said support and sacrificial metals having a purity of at least 99.0%;
• each contact pad attached to the reflow metal connection element of the respective chip bond pad;
• and
• said second substrate surface having contact pads in positions operable for connections to external parts, each contact comprising a connector stack to at least one of said vias, each of said stacks comprising a seed metal layer in contact with said via metal capable of providing an adhesive and conductive layer for electroplating on its surface, a first electroplated support metal layer secured to said seed metal layer, a second support metal layer on said first support layer, and at least one sacrificial metal layer on said second support layer, said support and sacrificial layers having a purity of at least 99.0%.