US Patent 7721422 Methods of making microelectronic assemblies

A method of making a microelectronic assembly includes providing a conductive metal layer having a first surface and a second surface, and etching the first surface of the conductive metal layer to form conductive protrusions, whereby after the etching step, the second surface of the conductive metal layer defines a substantially flat, continuous surface. The method includes juxtaposing a layer of an insulating material with tips of the conductive protrusions, and pressing the conductive protrusions through the layer of an insulating material so that the tips of the conductive protrusions are accessible at a first surface of the layer of an insulating material.