A microelectronic assembly may include a microelectronic element having a surface and a plurality of contacts at the surface; a first element consisting essentially of at least one of semiconductor or dielectric material, the first element having a surface facing the surface of the microelectronic element and a plurality of first element contacts at the surface of the first element; electrically conductive masses each joining a contact of the plurality of contacts of the microelectronic element with a respective first element contact of the plurality of first element contacts; a thermally and electrically conductive material layer between the surface of the microelectronic element and the surface of the first element and adjacent conductive masses of the conductive masses; and an electrically insulating coating electrically insulating the conductive masses and the surfaces of the microelectronic element and the first element from the thermally and electrically conductive material layer.