Gyroscope

A method of making a gyroscope,

• said gyroscope comprising an outer frame, an inner frame, proof masses, outer support suspensions which connect said outer frame and said inner frame, and inner support suspensions which connect said inner frame and each of said proof masses,
• said gyroscope being made integrally from an SOI (Silicon on Insulator) substrate which includes a silicon oxide film, a first silicon layer on one side of said silicon oxide film and a second silicon layer on the other side thereof,
• the method comprising:
• (a) depositing a silicone oxide film on a first surface of said SOI substrate and patterning said silicone oxide film,
• depositing an aluminum layer on said silicone oxide film and patterning said aluminum layer,
• depositing an aluminum layer on a second surface of said SOI substrate and patterning said aluminum layer;
• (b) etching portions that are not masked by said aluminum layer from said first surface, thereby forming a structure of the first silicone layer;
• (c) removing said aluminum layer from said first surface to expose said silicone oxide film, and then etching from said first surface again, thus etching portions that are not masked by said silicone oxide film, thereby forming the structure of said first silicone layer so that movable portions are spaced from an underlying surface;
• (d) etching from said second surface, thus etching portions that are not masked by said aluminum layer, thereby forming a structure of the second silicone layer;
• and
• (e) removing said silicone oxide film on said SOI substrate by sacrificial etching, thus separating said structures of said first and second silicone layers from said outer frame.