High-temperature pressure sensor and manufacturing method thereof

Abstract

The invention relates to a high-temperature pressure sensor and a manufacturing method thereof, and belongs to the field of micro-mechanical manufacturing. The high-temperature pressure sensor comprises a silicon substrate, sensitive elements arranged on the substrate, middle substrates, and upper layer silicon sheets. The middle substrates are arranged on the silicon substrate and made of high temperature resisting non-conductive materials. The upper layer silicon sheets are arranged on the middle substrates. The silicon substrate, the middle substrates and the upper silicon sheets are successively bonded. Cavity bodies for collecting the sensitive elements are arranged between the silicon substrate and the middle substrates. According to the invention, the silicon substrate, the middle substrates and the upper silicon sheets are successively superposed to form a silicon substrate-middle substrates-silicon sheets sandwich structure, so stress mismatch is mutually counteracted and stress balancing is achieved; and by adopting the manufacturing method of the high-temperature pressure sensor, the above mentioned effects can be achieved.

Description

technical field [0001] The invention relates to a high-temperature pressure sensor and a manufacturing method thereof, belonging to the field of micro-mechanical manufacturing. Background technique [0002] As one of the main products of micro-electromechanical systems (MEMS), high-temperature resistant pressure sensors have been widely used for pressure measurement in high-temperature environments in petrochemical, automotive electronics, aerospace and other fields. The current commercial pressure sensors are mainly silicon diffused piezoresistive pressure sensors. Because they use single crystal silicon as the substrate, P-type diffused resistors are made on N-type silicon substrates, and rely on reverse-biased PN junctions to achieve electrical isolation. When working When the temperature exceeds 120°C, the leakage current of the PN junction will increase, and the performance of the sensor will seriously deteriorate and even fail. [0003] In addition, high temperature r...

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Problems solved by technology

In addition, Colette also assembles the sensor chip and the protective layer wafer into a sensor diaphragm through electrostatic bonding technology, and then uses high-temperature conductive glass as a circuit connection between the sensor chip and the specially designed joint, which solves the problem of gold wire welding of traditional pressure sensors The problem of easy fatigue, but the stress balance problem after bonding and packaging is still difficult to eliminate

[0007] In summary, the packaging of existing high-temperature pressure sensors mostly adopts the method of low-temperature sintering of glass paste or the technology of monolithic silicon wafer-glass electrostatic bonding, which has the problem of stress balance; traditional sensors combine silicon chips and circuits through thin Gold wires are connected, and thin gold wires or welds are prone to fatigue and even failure due to high vibration or rapid pressure cycles; some high-temperature pressure sensors in existing technical solutions can not withstand very high temperatures and need to be further improved High temperature performance

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