Patent ID: 8430991

Claim:
A production apparatus for producing a near field optical head that includes, during its production process, a substrate, a protuberance extending from a surface of the substrate, an electrically conductive shielding film covering the protuberance and the substrate, and a parent film, as a mother material for an air bearing, covering the shielding film, the production apparatus comprising: a conductive etchant for etching the parent film to expose a portion of the protuberance corresponding to an apex of the shielding film so that the exposed apex protrudes from a surface of the parent film or lies on a common plane with the surface of the parent film; a container for storing the etchant and for containing the substrate, the shielding film, and the parent film so that the substrate, the shielding film, and the parent film are immersed in the etchant while the substrate and the shielding film are insulated from the etchant during etching of the parent film; a single electrode mounted in the container so as to be immersed in the etchant and disposed over the parent film, the electrode being electrically connected to the shielding film by an electrical connection passing via an exterior of the container; and measuring means for measuring an electrical characteristic between the electrode and the shielding film, the measuring means including stopping means for stopping etching of the parent film in accordance with the measured electrical characteristic corresponding to a conduction state in which the shielding film, the etchant, and the electrode become electrically conductive due to the exposed apex of the shielding film.