| abstract |
Vias ( 210, 210 B) are formed in a surface of a substrate. At least portions of contact pads ( 139, 350 ) are located in the vias. Contact pads ( 150, 340 ) of an integrated circuit structure are inserted into the vias and attached to the contact pads ( 139, 350 ) of the substrate. The vias provide a strong, reliable mechanical and electrical connection. A via may expose not only a contact pad ( 350 ) in the substrate but also a surrounding region. Solder ( 930 ) wets the contact pad better than the surrounding region, resulting in a stronger solder joint and better electrical conductivity. Alternatively, the contact may include multiple conductive layers ( 910.1, 910.2 ), with the top layer ( 910.2 ) being more solder wettable than the bottom layer ( 910.1 ) and the top layer covering only a portion of the bottom layer. |