| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 87 === A miniature thermal conductivity detector has been designed and fabricated by silicon based micromachining. The sensor consists of four serpentine nickel thin films, which has highest temperature coefficient of resistivity than other common metal. The Ni film resistors are supported on a Pyrex glass membrane. The Pyrex glass of 500μm is anodically bonded on a silicon chip first, and then ecthed and lapped to 40μm. The silicon chip has been previously etched with two cavities to reduce heat dissipation. The Pyrex glass serves as substrate for Ni film resistors that are aligned with silicon cavities. Gold films are also deposited for wire bonding pads. Another piece of silicon chip etched with two gas channels of 500X10000X20μm are aligned with Ni film resistors and then bonded with epoxy. With wire bonding on the gold pads, a micro-gas thermal conductivity detector is finished. The resistances are also calibrated. The miniature thermal conductivity detector not only can be used in a micro gas chromatography but also be formed a gas flow sensor, vacuum sensor, gas leak sensor, temperature sensor and microcalorimeter.
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