Package and methods for the fabrication and testing thereof

Provided are methods of forming sealed via structures. One method involves: (a) providing a semiconductor substrate having a first surface and a second surface opposite the first surface; (b) forming a layer on the first surface of the substrate; (c) etching a via hole through the substrate from the second surface to the layer, the via hole having a first perimeter at the first surface; (d) forming an aperture in the layer, wherein the aperture has a second perimeter within the first perimeter; and (e) providing a conductive structure for sealing the via structure. Also provided are sealed via structures, methods of detecting leakage in a sealed device package, sealed device packages, device packages having cooling structures, and methods of bonding a first component to a second component.