Thermal diffusivity sensor chip with silicon cup structure and preparation method of thermal diffusivity sensor chip

Abstract

The invention provides a thermal diffusivity sensor chip with a silicon cup structure and a preparation method of the thermal diffusivity sensor chip. The chip comprises an SOI (silicon on insulator) wafer, the SOI wafer consists of monocrystalline silicon, buried-layer silicon dioxide and a silicon substrate, the buried-layer silicon dioxide is arranged on the monocrystalline silicon, the silicon substrate is disposed on the buried-layer silicon dioxide, a heat-insulation cavity is disposed on the silicon substrate, the bottom buried-layer silicon dioxide is exposed via the heat-insulation cavity, heaters, a first temperature sensor and second temperature sensors are arranged on the bottom surface of the heat-insulation cavity, the heaters and the second temperature sensors are arranged around the first temperature sensor in a centrosymmetric manner, and each heater is disposed between the first temperature sensor and the corresponding second temperature sensor. Heat is transferred in the corroded heat-insulation cavity during measurement, a heat-insulation effect is good, measurement precision is high, the chip can sufficiently detect heat transfers in all directions, is fast in response and can detect differences among the heat transfers of fluid in the different directions, and more data can be obtained by means of selectively energizing the four heaters or selectively loading different powers on the four heaters, so that measurement results are true and more reliable.

Description

technical field [0001] The invention relates to the technical field of thermal diffusivity sensor chips, in particular to a thermal diffusivity sensor chip with a silicon cup structure and a preparation method thereof, which are used for measuring fluid thermal diffusivity. Background technique [0002] Thermal diffusivity is a physical quantity that reflects the thermal conductivity of a material. There are generally two ways to determine the thermal diffusivity of a substance through theoretical calculation and experimental measurement. From the aspect of theoretical calculation, the thermal diffusivity of the material can be obtained by mathematical analysis and calculation by determining the heat conduction mechanism of the material and analyzing the physical model. However, the thermal diffusivity varies greatly due to the difference in material composition and structure, so it is very difficult to determine it theoretically. Except for a few substances, it is difficul...

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Problems solved by technology

Although the measurement accuracy can be improved to a certain extent, the influence of the heat capacity and diameter of the thermal probe itself is not considered, and the system error cannot be avoided.

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