Method of fabricating deflection aperture array e.g.for electron beam exposure apparatus; wet etching

摘要

A method for fabricating a deflection aperture array having deflection electrodes adjacent each aperture, e.g. a blanking aperture array for electron beam lithography, comprises forming a wiring pattern 305 on a substrate 301 of a wafer, covering the pattern with a dielectric layer 306, forming recesses 303 in the substrate in positions corresponding to the apertures, forming contact holes to expose parts of the wiring pattern, depositing a conductive film pattern 308 (fig 7L) over the dielectric layer and in the contact holes, using the conductive film pattern as an electrode to form the deflection electrodes 309 by plating, removing the conductive film 308 and then wet etching to remove part of the back of the substrate 301 opposite the recesses 303 so that apertures are formed through the substrate as in fig 9B. By removing the conductive film before wet etching, contamination of the finished array is reduced. A jig 51 for wet etching is described (fig 12B), the jig sealing the surface of the wafer 44 which is not to be etched in a gas filled chamber 53 so that it is not exposed to the etching liquid. The pressure in the chamber 53 may be controlled in response to the output of a sensor 64 to prevent the wafer breaking. Alternatively, the chamber may communicate with the atmosphere. Change in the pressure is one of several techniques described which be used to detect the endpoint of the etching.