Wafer processing techniques for near field magneto-optical head

Abstract

A method of making and self-aligning a disk data storage read/write head that uses a catadioptric focusing device (or lens) having a high numerical aperture (NA), which does not introduce significant spot aberration on a storage medium. The manufacturing process of the head is carried out at a wafer level, and is facilitated significantly by the flatness of the focusing device. An exemplary manufacturing process is implemented as follows: A lens coil/plate is formed by molding a flat optical substrate to form the desired lens shapes. Coil cavities or depressions are formed simultaneously with the lens to accommodate a coil. Conductive plugs are formed in proximity to cutting lines for wire bonding attachment to the coil. A slider wafer is formed and bonded to the lens/coil wafer. Coils and pedestals are also formed on the lens/coil plate using thin-film processing techniques, and reflective surfaces are deposited on the bottom surface of the substrate, opposite the lens. The focusing device includes an incident surface, a reflective surface, a focal pedestal, and a body. The incident surface is generally flat and is comprised of a central diffractive, optically transmissive surface and a peripheral reflector. The peripheral reflector is comprised of a reflective-diffractive surface, or alternatively, a reflective-kinoform phase profile.