A dielectric element has a plurality of contacts at a first surface and a plurality of first traces coupled thereto which extend in directions parallel to the first surface. A circuit structure made of a plurality of dielectric layers and electrically conductive features thereon includes a plurality of bumps at a first surface which face the contacts of the dielectric element and are joined thereto. Circuit structure contacts at a second surface opposite the first surface are electrically coupled with the bumps through second traces on the circuit structure, the circuit structure contacts configured for connection with a plurality of element contacts of each of a plurality of microelectronic elements, wherein the microelectronic elements can be assembled therewith such that element contacts thereof face and are joined with the circuit structure contacts.