Manufacture of field emission elements

A method of manufacturing a field emission element, comprising the steps of:

• (a) forming a surface layer including a gate film made of a conductive material on a substrate;
• (b) forming a resist pattern on the surface layer by photolithography, the resist pattern having an opening with a predetermined shape;
• (c) reflowing the resist pattern to make the opening have an inner diameter gradually reducing toward the substrate;
• (d) anisotropically etching the gate film by using the reflowed resist pattern as a mask to form an opening through the gate film, the opening having an inner diameter reducing gradually toward the substrate;
• (e) forming a first sacrificial film covering the gate film having the opening;
• (f) forming an emitter film made of a conductive material on the first sacrificial film;
• and
• (g) removing a portion or a whole of the substrate and a portion of the first sacrificial film to expose the emitter film and the gate film.