CN-120057845-B - Multi-temperature-zone micro-heating plate based on thermal cross and manufacturing method

CN120057845BCN 120057845 BCN120057845 BCN 120057845BCN-120057845-B

Abstract

The invention belongs to the technical field of MEMS (micro electro mechanical systems), and particularly relates to a multi-temperature-zone micro thermal plate based on thermal cross and a manufacturing method thereof. The micro-hotplate integrates a plurality of heaters on the supporting layer, each heater corresponds to one working area, temperature control is achieved through adjusting input voltage or current of each heater, the working areas are communicated with each other, the thermal cross effect among the working areas is further fully utilized, linkage control of a plurality of temperature working areas on a single micro-hotplate is achieved, accordingly a working mode of single micro-hotplate multi-temperature area coding control is achieved, the thermal cross effect is effectively utilized through the communication among the temperature areas, and overall power consumption of the micro-hotplate is reduced.

Inventors

WEI GUANGFEN
YANG YOUPENG
JIAO SHASHA
LIN ZHONGHAI
ZHANG WEI

Assignees

山东工商学院

Dates

Publication Date: 20260512
Application Date: 20250226

Claims (7)

1. The multi-temperature-zone micro-heating plate based on thermal cross is characterized by comprising a silicon-based substrate, a supporting layer, a heating unit, an insulating layer and a detection unit; the support layer is positioned above the silicon-based substrate and used for supporting the upper structure of the micro-hotplate and isolating heat generated by the heating unit; The heating unit is arranged above the supporting layer and comprises a plurality of heaters, wherein each heater corresponds to one working area to form a plurality of encodable temperature areas; The insulating layer covers the heating unit and is used for electrically isolating and reducing heat conduction loss; The detection unit is positioned above the insulating layer and comprises a plurality of detection electrodes which are in one-to-one correspondence with the heaters and are used for sensing and reading response signals of the gas-sensitive functional material to target gas; The distance between the working areas is optimally set according to the comprehensive influence of the thermal cross effect on the peak temperature, mechanical deformation and temperature distribution uniformity of the micro-hotplate; the peak temperature model of the micro-hotplate is the peak temperature of the micro-hotplate With distance Is in a non-linear decreasing trend at a spacing approaching a critical value Tend to stabilize, expressed as: ; Wherein, the A fourth term coefficient is expressed for describing a nonlinear rapid change in peak temperature with increasing spacing; representing a cubic term coefficient reflecting trend correction of the next level in the nonlinear variation; Representing the quadratic coefficient for controlling the degree of curvature of the peak temperature drop curve; Representing a first term coefficient, describing the basic trend of linear decrease of peak temperature along with the distance, and directly relating to the linear part of integral change; a constant term, i.e., a theoretical peak temperature when the spacing approaches a minimum; through the space The corresponding peak temperature is obtained, so that the peak temperature and the change rule of the micro-hotplate under different intervals are evaluated, and a reference basis is provided for optimizing the structural design and performance regulation of the micro-hotplate; Temperature distribution model of the micro-hotplate With distance The increase gradually flattens out, and the relation is expressed as: ; Wherein, the Represents a lateral distance; And (3) with The amplitude weights of the two Gaussian distributions are respectively expressed and used for describing the influence intensity of the transverse distance and the distance on the temperature distribution; And (3) with Respectively representing the central positions of two Gaussian distributions and the peak positions of corresponding temperature distributions; And (3) with Standard deviation of the gaussian distribution is respectively represented, reflecting the extended width and range of the peak temperature; Quadratic function part The definition is as follows: ; In the above-mentioned method, the step of, 、、 The specific influence of the high-order nonlinearity on the temperature distribution is reflected for the coupling coefficient of the high-order nonlinearity change related to the distance and the transverse distance in the temperature distribution; 、、 The coefficient for describing medium nonlinear variation in the temperature distribution reflects the medium nonlinear trend of the temperature distribution along with the change of the distance and the transverse distance, and plays a role in smooth adjustment in the overall distribution; 、、 The coefficient for describing the integral linear change trend in the temperature distribution characterizes the change rule of the temperature in the transverse distance and the integral distribution characteristic of the change along with the distance.
2. A multi-temperature zone micro-hotplate based on thermal crossover according to claim 1, wherein the heater employs segmented discontinuous graded width heater electrodes.
3. A multi-temperature zone micro-hotplate based on thermal crossover according to claim 2, wherein the electrode width of the heating electrode increases progressively and discontinuously from edge to center, and the electrode spacing of the heating electrode is uniform.
4. The multi-temperature zone micro-hotplate based on thermal crossover of claim 1, wherein the mechanical deformation model of the micro-hotplate is mechanical deformation With distance Is in a decreasing trend, the relationship is expressed as: ; Wherein, the The fourth term coefficient is used for describing the enhancement trend of nonlinear change of mechanical deformation along with the increase of the distance, and reflects the influence of a higher nonlinear part in the deformation descending process; Representing a third-order term coefficient, describing a second-order nonlinear trend of deformation change, and adjusting the integral smoothness of a deformation curve; the secondary coefficient is represented, the medium trend regulation of deformation change influences the curvature characteristic of mechanical deformation when the distance is decreased; Representing a primary term coefficient, describing a part which is linearly related to the distance in the deformation descending process, and providing support for the linear reference trend of the curve; Representing a constant term, i.e. an initial value of theoretical mechanical deformation at minimum spacing; and calculating corresponding mechanical deformation through inputting the distance d, so as to analyze the mechanical response characteristics of the micro-hotplate at different distances.
5. The multi-temperature zone micro-hotplate based on thermal crossover of claim 1, wherein the material used for the supporting layer is SiO 2 , and the insulating layer comprises a high-thermal-conductivity material Si 3 N 4 and a low-thermal-conductivity material SiO 2 to form a Si 3 N 4 -SiO 2 composite film.
6. The multi-temperature-zone micro-hotplate based on thermal cross of claim 5, wherein the support layer and the insulating layer form a SiO 2 -Si 3 N 4 -SiO 2 composite dielectric film, and a plurality of rectangular etching windows penetrating through the composite dielectric film are distributed on the composite dielectric film.
7. A method of manufacturing a thermal crossover-based multiple temperature zone micro-hotplate as claimed in any one of claims 1 to 6, comprising the steps of: step 1, preparing a silicon-based substrate; step 2, forming a supporting layer on the silicon-based substrate by adopting a thermal oxidation process; step 3, manufacturing a heating unit by using a sputtering process and a photoetching-stripping process, wherein each heater in the heating unit corresponds to one working area; step 4, chemical vapor deposition of Si 3 N 4 above the heating unit; Step 5, continuing vapor deposition of SiO 2 above Si 3 N 4 to form a Si 3 N 4 -SiO 2 composite film; Step 6, introducing an annealing process and a chemical mechanical polishing process to eliminate residual force and planarize the surface; Step 7, forming a detection unit above the insulating layer by adopting a sputtering process and a photoetching-stripping process, wherein detection electrodes in the detection unit correspond to the heaters one by one; And 8, forming a back etching area by wet etching, dry etching or combination etching of the wet etching and the dry etching, and forming a front etching window structure on the front.

Description

Multi-temperature-zone micro-heating plate based on thermal cross and manufacturing method Technical Field The invention belongs to the technical field of MEMS (Micro-Electro-MECHANICAL SYSTEMS, micro Electro mechanical system), and particularly relates to a multi-temperature zone Micro-thermal plate based on thermal cross and a manufacturing method thereof. Background In the field of gas detection, metal oxide semiconductor (Metal Oxide Semiconductor, MOX) gas sensors are the preferred solution for practical gas sensors by virtue of excellent physical and chemical properties. The working principle of the metal oxide semiconductor gas sensor is based on the response of the gas-sensitive functional material to the target gas, and the gas-sensitive functional material generally shows the best detection performance at the working temperature of 100-500 ℃. With the development of Micro-electro-mechanical system technology, micro-heat plates (Micro-hotplate, MHP) are widely used in metal oxide semiconductor gas sensors to provide an operating temperature environment required for a gas-sensitive functional material by embedding a heating wire into a dielectric film. Although the micro-hotplate-based metal oxide semiconductor gas sensor has remarkable advantages in terms of providing heating conditions, the problems of poor gas selectivity and cross sensitivity are still faced in practical application, namely, the response of the gas-sensitive functional material to various gases is non-unique, and accurate distinction of the various gases is difficult to realize. In order to solve the selectivity problem, the existing research mostly adopts the design of an integrated sensor array, and the overall selectivity is improved by increasing the number of sensing elements. However, one significant drawback of this approach is a significant increase in power consumption. Meanwhile, although the design of integrating multiple sensors on a single chip can achieve miniaturization and high integration of devices, it is difficult to perform accurate temperature regulation for each working area. Therefore, an innovative micro-hotplate design is needed in the art to optimize temperature control and balance power consumption, and lay a foundation for the development and wide application of subsequent high-performance portable gas sensors. Disclosure of Invention In order to overcome the problems in the prior art, the invention provides a multi-temperature-zone micro-hotplate based on thermal cross and a manufacturing method thereof. The technical scheme for solving the technical problems is as follows: In a first aspect, the invention provides a multi-temperature-zone micro-thermal plate based on thermal cross, which comprises a silicon-based substrate, a supporting layer, a heating unit, an insulating layer and a detection unit; the support layer is positioned above the silicon-based substrate and used for supporting the upper structure of the micro-hotplate and isolating heat generated by the heating unit; The heating unit is arranged above the supporting layer and comprises a plurality of heaters, wherein each heater corresponds to one working area to form a plurality of encodable temperature areas; The insulating layer covers the heating unit and is used for electrically isolating and reducing heat conduction loss; The detection unit is positioned above the insulating layer and comprises a plurality of detection electrodes which are in one-to-one correspondence with the heaters and are used for sensing and reading response signals of the gas-sensitive functional material to target gas. Further, the heater adopts a heating electrode with a segmented discontinuous and gradual width. Further, the electrode width of the heating electrode is gradually increased from the edge to the center in a discontinuous mode, and the electrode spacing of the heating electrode is uniform. Further, each heater corresponds to one working area, temperature control is achieved by adjusting input voltage or current of each heater, and a plurality of encodable temperature areas are formed and are communicated with each other. Further, the distance between the heaters needs to be comprehensively considered and set according to the uniformity of the temperature distribution of the micro-hotplate, the power consumption and the mechanical deformation of the micro-hotplate. Further, the peak temperature model of the micro-hotplate is characterized in that the peak temperature T (d) of the micro-hotplate has a nonlinear descending trend along with the increase of the spacing d, and the peak temperature T (d) of the micro-hotplate tends to be stable at the spacing close to a critical value d critical, and is expressed as: T(d)＝a4d4+a3d3+a2d2+a1d+a0,d≤dcritical; Wherein a 4 represents a fourth term coefficient for describing a nonlinear rapid change of peak temperature with increasing pitch, a 3 represents a third term coefficient reflecting a trend correct