The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 12, 1996
Filed:
Jun. 19, 1995
Alberta Microelectronic Centre, Edmonton, CA;
Harris Canada Inc., Calgary, CA;
Abstract
Capacitive microphones are fabricated using etch-release of sacrificial silicon by an isotropic dry etchant. The process allows the production of a microphone largely from CVD processes with flexibility in materials selection. The dry etch chemistry does not require freeze-drying after release. The etchant does not attack electrodes or metallized circuitry and so allows the placement of the electrodes between the backplate and diaphragm dielectric layers. Diffusion barrier layers between the sacrificial and electrode layers protect both materials from interdiffusion during device fabrication. The process is especially fitting for a microphone comprising silicon nitride dielectric layers with aluminum electrodes.