MEMS (Micro Electro Mechanical System) technology-based thermal diffusivity sensor chip and manufacturing method thereof

Abstract

The invention provides an MEMS (Micro Electro Mechanical System) technology-based thermal diffusivity sensor chip and a manufacturing method thereof. The sensor chip comprises a silicon dioxide isolation layer deposited on the upper surface of an SOI (Silicon On Insulator) wafer, a heater and temperature sensors deposited on the upper surface of the silicon dioxide isolation layer and formed by etching, as well as silicon nitride protective layers which are deposited on the upper surface of the silicon dioxide isolation layer, the upper surface of the heater and the upper surfaces of the temperature sensors, wherein a heat insulation cavity is etched on the SOI wafer upwards from the lower surface to the lower surface; the heater is positioned in the central position of the upper surface of the silicon dioxide isolation layer; and the temperature sensors are uniformly distributed in the radial direction taking the heater as a center. According to the sensor chip provided by the invention, the thermal conductivity factor of fluids can be measured in dozens of seconds only by means of a few microliters of sample liquid, and the measurement can be realized in a large temperature range.

Description

technical field [0001] The invention relates to a thermal diffusivity sensor chip based on MEMS (microelectronic system), in particular to a thermal diffusivity sensor chip based on MEMS technology and a preparation method thereof, which are used for measuring fluid thermal diffusivity. Background technique [0002] There are many ways to measure the thermal diffusivity of a fluid. The thermal diffusivity is an important transfer property of a fluid. To determine the thermal diffusivity of a fluid, there are generally two ways: theoretical calculation and experimental measurement. Since there is no complete theory of the packing structure of fluid molecules, the formulas and models assumed by these estimates are idealized and simplified, and do not fully conform to the complex actual situation, often resulting in large errors, and these equations are generally only applicable to Specific systems and ranges, many fluids still need experimental determination. Therefore, exper...

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Problems solved by technology

For example, the thermal probe measurement method and the transient double-heated wire method are used to measure the thermal diffusivity. Although the above technologies can improve the measurement accuracy to a certain extent, there are still problems that require too many samples, long time or complicated equipment. Happening

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