Patent ID: 7999379

Claim:
A microelectronic assembly comprising: a microelectronic element having a first surface and contacts accessible at the first surface; a compliant layer overlying a portion of the first surface of said microelectronic element, the compliant layer having a top surface remote from the first surface and a sloping transition surface extending away from the top surface, wherein at least a portion of at least one of the contacts is exposed beyond the sloping transition surface of the compliant layer; conductive traces extending along the sloping transition surface and the top surface of said compliant layer, said traces connected with the contacts; a plurality of substantially rigid metal posts overlying said compliant layer and projecting away from the first surface of said microelectronic element, said substantially rigid metal posts disposed remote from said contacts, each said substantially rigid metal post having a monolithic metal layer extending directly from a trace of said traces and extending above a height of said traces and to a majority of a height of such post, wherein said monolithic metal layer consists essentially of at least one metal selected from the group consisting of: copper, copper alloys, gold and combinations thereof, and nickel, each said substantially rigid metal post having a base adjacent said compliant layer and a tip remote from said compliant layer, said base having a width along a surface of the compliant layer not greater than a width of any other portion of said substantially rigid metal post; a solder mask overlying portions of the conductive traces, the solder mask having an exposed top surface and openings, wherein the substantially rigid metal posts extend through the openings to a height above the top surface of the solder mask; and wherein said solder mask is a conformal layer such that a height of the to surface of the solder mask above the first surface of the microelectronic element varies with a shape of the compliant layer.