Method for fabricating three-dimensional microstructures and a high-sensitivity integrated vibration sensor using such microstructures

Abstract

Abstract A method for preferentially etching phosphosilicate glass to form a micromechanical structure includes forming a layer of phosphosilicate glass on a substrate and opening at least one via in the phosphosilicate glass layer. A layer of material which is patterned to produce a micromechanical structure is formed over the phosphosilicate glass layer which extends through the via and adheres to the substrate. The phosphosilicate glass layer is then removed by immersing the device in an etchant bath containing an aqueous ammoniacal hydrogen peroxide solution. The resulting micromechanical structure has at least one point of attachment to the substrate and is otherwise spaced apart from the substrate by an air gap. A method for attaching an overhanging mass to a miniature cantilever beam using microelectronics fabrication technology is also provided in which the center of gravity is shifted to the endpoint of the free end of the beam. There is further provided an integrated sensor which includes at least one micromechanical transducing structure and on-board detection circuitry which detects extremely small motions of the structure and produces a corresponding digital output.

Inventors

• 👤 Kailash C. Jain
• 👤 Jacob A. Abraham

Bibliographic Details