A process for the preparation of a photoactive substrate, which is suitable for microfabrication

Methods of manufacture and apparatus with holes for electrical conductivity, which is produced by a photosensitive glass substrate is prepared which comprises at least silica, lithia, aluminum oxide and cerium oxide, a design layout is masked, which comprises one or more holes, so that one or more electrically conductive paths are formed on the photosensitive glass substrate, at least a portion of the photosensitive glass substrate to an activating energy source is exposed to the photosensitive glass substrate a heating phase of at least ten minutes is exposed to its glass transition temperature, the photosensitive glass substrate is cooled by at least a portion of the exposed convert the glass to a crystalline material, so that a glass-crystalline substrate is formed, and the glass-crystalline substrate is etched with an etching solution to the f one or more recesses or through holes UR to form the electrical conductivity in the device.