Patent ID: 7163872

Claim:
A method of manufacturing a tunable wavelength optical filter, comprising the steps of: (a) forming a sacrificial oxide film for floating a mirror on a semiconductor substrate; (b) sequentially laminating conductive silicon films and oxide films for defining a mirror region on said sacrificial oxide film in a multi-layer and laminating another conductive silicon film to form a mirror; (c) etching the rear side of said semiconductor substrate to form an opening for inserting an optical fiber thereinto; (d) forming electrode pads for controlling the gap between the mirrors by an electrostatic force; (e) etching the silicon film around said mirror in a dry etching method to expose said sacrificial oxide film, such that said mirror is suspended by a connecting means; and (f) etching said sacrificial oxide film with hydrogen fluoride such that said mirror is floated on said semiconductor substrate; wherein two semiconductor substrate formed by said steps (a) to (f) are prepared and are attached to each other through a spacer layer therebetween so that the mirrors of said semiconductor substrates are opposite to each other.