Patent ID: 7393793

Claim:
A method of manufacturing a tunable wavelength optical filter, comprising the steps of: (a) forming a first sacrificial oxide film for floating a lower mirror on a semiconductor substrate; (b) sequentially laminating conductive silicon films and oxide films for defining a mirror region on said first sacrificial oxide film in a multi-layer and laminating another conductive silicon film to form a lower mirror; (c) forming a second sacrificial film on the resultant; (d) sequentially laminating conductive silicon films and oxide films for defining the mirror region on said second sacrificial oxide film in a multi-layer and laminating another conductive silicon film to form an upper mirror; (e) etching the rear side of said semiconductor substrate to form an opening for inserting an optical fiber thereinto; (f) forming electrode pads for controlling the gap between said lower mirror and said upper mirror by an electrostatic force; (g) etching the silicon film around said upper mirror in a dry etching method to expose said second sacrificial oxide film, such that said upper mirror is suspended by a connecting means; and (h) forming an optical tuning space between said lower mirror and said upper mirror and etching said first sacrificial oxide film and said second sacrificial oxide film such that said lower mirror is floated on said semiconductor substrate.