Interconnect layer contact and method for improved packaged integrated circuit reliability

Abstract

Packaged photosensor ICs are made by fabricating an integrated circuit (IC) with multiple bondpads; forming vias from IC backside through semiconductor to expose a first layer metal; depositing conductive metal plugs in the vias; depositing interconnect metal; depositing solder-mask dielectric over the interconnect metal and openings therethrough; forming solder bumps on interconnect metal at the openings in the solder-mask dielectric; and bonding the solder bumps to conductors of a package. The photosensor IC has a substrate; multiple metal layers separated by dielectric layers formed on a first surface of the substrate into which transistors are formed; multiple bondpad structures formed of at least a first metal layer of the metal layers; vias with metal plugs formed through a dielectric over a second surface of the semiconductor substrate, interconnect metal on the dielectric forming connection shapes, and shapes of the interconnect layer coupled to each conductive plug and to solder bumps.