CN113985069A - Dynamic heat source pendulum type omnibearing micro mechanical accelerometer and processing method thereof - Google Patents
Dynamic heat source pendulum type omnibearing micro mechanical accelerometer and processing method thereof Download PDFInfo
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Abstract
The application discloses a dynamic heat source pendulum type omnibearing micro mechanical accelerometer and a processing method thereof, wherein the accelerometer comprises a substrate layer, a sensitive layer and a cover plate, the sensitive layer comprises a middle heating cavity and a middle detection cavity, and the upper surface of the sensitive layer is provided with an omnibearing dynamic heat source pendulum heater and four pairs of thermistors; the omnidirectional moving heat source swinging heater is suspended at the central position of the sensitive layer through six completely symmetrical semicircular spokes; the electrifying modes of the heater and the thermistor are constant current; the cover plate is etched with a groove and is hermetically connected with the upper surface of the sensitive layer. The invention can realize the omnibearing measurement of the acceleration, has high sensitivity, high response speed, small structural stress, small volume and light weight, and can realize batch production. Meanwhile, the structure and the processing technology are very simple, the cost is extremely low, the reliability is high, and the micro-accelerometer market which is competitive with the solid pendulum type micro-mechanical accelerometer and has low precision and low price becomes possible.
Description
Technical Field
The invention relates to the technical field of detecting acceleration attitude parameters of a motion carrier by utilizing the swing of an omnidirectional moving heat source pendulum under the action of linear acceleration, in particular to a moving heat source pendulum type omnidirectional micro mechanical accelerometer and a processing method thereof, and belongs to the field of inertial measurement.
Background
Due to the application requirements of the carrier attitude measurement in various fields of civil vehicles, railway construction, industrial production, bridge construction, seismic research, geodetic surveying, geological exploration, marine investigation, satellite communication, robot engineering and the like, in recent years, the organic combination between the sensor technology and the emerging scientific technology enables the attitude sensor to develop towards microminiature, comprehensive and intelligent. Current attitude sensors include gyros and accelerometers. The uniaxial accelerometer is used for sensing the acceleration applied to the plane of the carrier along a specific direction, such as an X sensitive axis or a Y sensitive axis in a rectangular coordinate system of the carrier. However, in practical use of the sensor, the acceleration applied to the carrier can be applied along any azimuth angle of the carrier plane, and it is difficult to predict the acceleration input in a certain direction, so that an accelerometer capable of sensing the input along any azimuth angle in the carrier plane, namely an omnidirectional accelerometer, is needed. In the robot industry, detection is desired to be carried out in all directions for controlling the walking and working postures of the robot and in the fields of aviation, aerospace, ships, weapons and automation, and the detection is particularly significant for controlling the postures of shaking carriers such as ships, buoys, floating sonars and the like.
The most common among accelerometers is the pendulum acceleration sensor. The pendulum tilt sensor commonly used at present has three types, namely a liquid pendulum type sensor, a solid pendulum type sensor and a heat flow type sensor. The solid pendulum type tilt angle sensor has the advantages of complex structure, high cost, large motion amplitude of the solid pendulum and difficulty in bearing high overload or impact. The main problems of the liquid pendulum tilt angle sensor are that the number of structural components is large, the response time is long, and the performance changes greatly along with the temperature. The heat flow type accelerometer has the characteristics of small sensitive mass, simple structure, high overload bearing capacity, short response time, good temperature performance, low cost and the like, and can be applied to severe environments. Therefore, in the micro-acceleration sensor, the micro-mechanical (MEMS) heat flow acceleration is unique in the MEMS sensor by its ultra-high impact resistance and ultra-low manufacturing cost, and is not comparable to other MEMS sensors.
The working principle of the micro-mechanical (MEMS) heat flow accelerometer is as follows: the resistance heater is arranged in the closed cavity, the parallel detection thermistors are symmetrically distributed around the resistance heater, the resistance heater is electrified and heated to form a heat source to emit heat flow to the periphery, and the temperature fields are symmetrically distributed, so that the influence on the thermistors is consistent. When the external wired acceleration is input, the flowing direction of hot air flow is the same as the acceleration direction, and the hot air flow changes towards the input acceleration direction, so that the temperature field of the air flow is asymmetrically distributed, the temperature changes of two adjacent detection thermistors in the same direction are opposite, and the two detection thermistors generate temperature difference. The acceleration can be detected by detecting the temperature difference through the Wheatstone bridge. Chinese patent: a micro silicon bridge type thermal convection acceleration sensor (patent application No. 02116842.3) is a sensor sensitive to an input acceleration in a specific direction, and cannot perform omnidirectional acceleration measurement. The prior art generally uses the projection of the input acceleration on the sensitive axis to calculate the magnitude of the acceleration. On one hand, the method needs a large amount of subsequent calculation, has slow response speed, can not carry out rapid measurement and is inconvenient to introduce into an automatic control system; on the other hand, the loss of sensitivity is replaced by the loss of sensitivity, and the sensitivity of the sensor is low. In the prior art, because the velocity of hot air flow is very low, and the gradient of an asymmetric temperature field caused by the movement of air flow under the action of acceleration is very small, the unbalanced voltage output by a Wheatstone bridge consisting of thermistors is small, and the sensitivity of a sensor is low. Although the sensitivity can be improved by increasing the heater power, the sensitivity is not substantially changed or improved due to the limitation of power consumption, and it is difficult to break through the bottleneck of practical use.
Disclosure of Invention
The invention aims to provide a dynamic heat source pendulum type omnibearing micro mechanical accelerometer to solve the technical problems in the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a pendulum type omnibearing micro mechanical accelerometer with a dynamic heat source, which comprises a cover plate and a sensitive layer, wherein,
the sensitive layer comprises a middle heating cavity and a middle detection cavity, and an omnidirectional movable heat source swinging heater and four pairs of thermistors are arranged at the central position of the sensitive layer;
defining the length and width directions of the rectangular accelerometer as X and Y directions respectively, and the height direction of the sensitive layer as Z direction; the heater is suspended at the center of the sensitive layer through six completely symmetrical semicircular spokes, and the thermistors are distributed around the heater in a regular octagon shape; the eight thermistors are arranged oppositely in pairs and used for detecting the acceleration in all directions;
the heater is suspended at the center of the sensitive layer through six completely symmetrical semicircular spokes, a circular middle heating cavity is arranged below the heater, and eight thermistors are arranged around the position of the heater in a regular octagonal distribution manner;
two ends of the omnidirectional moving heat source pendulum heater are covered with symmetrical electrodes along the Y direction to form a moving resistance type heat source;
the electrifying modes of the heater and the thermistor are constant current;
as a further technical scheme, a groove is etched in the cover plate and is connected with the upper surface of the sensitive layer in a sealing mode.
As a further technical scheme, the cover plate and the substrate layer isolate the gas media of the intermediate heating cavity and the intermediate detection cavity from the outside to form a sealed working system; the height of the middle heating cavity and the middle detection cavity and the depth of the groove in the upper sealing layer are the total cavity height z, and z is more than or equal to 300 mu m and less than or equal to 1000 mu m.
As a further technical solution, the depth of the groove of the cover plate is 2/3 of the height of the cover plate.
As a further technical scheme, the height of the heater and the thermistor is 100nm to 1000 nm.
As a further technical scheme, the length of the thermistor is 1/6-1/5 of the width of the whole sensitive layer.
As a further technical scheme, the heater and the thermistor are both composed of metal layers consisting of a chromium adhesion layer and a platinum layer.
A method for processing a pendulum type omnibearing micro mechanical accelerometer with a dynamic heat source comprises the following specific process flows:
the method comprises the following steps: thermally oxidizing a 0.5 μm thick silicon dioxide film on an N-type (100) single crystal silicon wafer;
step two: photoetching the silicon dioxide film to form structural patterns of an omnidirectional dynamic heat source pendulum heater and a thermistor;
step three: sputtering a metal layer consisting of a chromium adhesion layer and a platinum layer on the photoresist and the silicon dioxide in sequence by a magnetron sputtering process;
step four: stripping off the metal layer outside the all-directional movable heat source pendulum heater and the thermistor structure pattern by adopting an ultrasonic stripping process to form an all-directional movable heat source pendulum heater and a thermistor structure;
step five: etching off a part of silicon dioxide by adopting photoetching and wet etching processes;
step six: a groove with the depth of 300 mu m is formed by corrosion processing by adopting a silicon etching process, so that the omnidirectional moving heat source pendulum heater and the thermistor are suspended and fixed on the sensitive layer through a silicon dioxide film to finish the processing of the sensitive layer;
step seven: and bonding the cover plate and the sensitive layer by a bonding process to enable the upper surface of the sensitive layer to be positioned in the closed cavity to complete the processing of the sensitive element.
By adopting the technical scheme, the invention has the following beneficial effects:
1. the dynamic heat source pendulum type omnibearing micro mechanical accelerometer inherits the advantages of an MEMS heat flow accelerometer, and is small in size, light in weight and easy to intelligentize and integrate.
2. The sensitive structure of the accelerometer is an omnidirectional moving heat source pendulum heater. The omnidirectional movable heat source pendulum can swing up and down along a Z axis vertical to the plane of the sensitive layer, can swing on any azimuth angle on the plane of the sensitive layer XOY, and can sense the input acceleration on any azimuth angle of the plane of the XOY, so that the omnidirectional measurement of the acceleration is realized without the limitation of the azimuth angle, and the omnidirectional movable heat source pendulum has high sensitivity and high response speed.
3. The omnibearing movable heat source pendulum is suspended on the plane of the vibrator through six completely symmetrical high-elasticity semicircular spokes, so that the omnibearing movable heat source pendulum has high structural symmetry and small structural stress, and can realize the consistency of detection of any azimuth angle.
4. The omnibearing movable heat source pendulum adopts a wind-fire wheel type sensitive structure, and a central wheel hub is a mass block and is also a heater. The sensitive structure of the wind-fire wheel type has the following advantages: the sensitive structure is adopted for central support, so that the structural stress is small; the structure symmetry is high, and the consistency of detection of any azimuth angle can be realized; the wind-fire wheel type sensitive structure can realize that a relatively long elastic element and a relatively large mass block are manufactured in a small area, so that high inertia force sensitivity is obtained. 5. The sensitive element is manufactured on a silicon chip by the processes of photoetching, corrosion and the like, has good consistency, is convenient for introducing a microcomputer embedded system (singlechip), is easy to realize intellectualization and integration, and accords with the development direction of the sensor towards microminiature, synthesis and intelligence. .
6. The micro-accelerometer has the advantages of simple structure and processing technology, extremely low cost and high reliability, and makes the micro-accelerometer market with low precision and low price possible to compete with a solid pendulum type micro-mechanical accelerometer.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic three-dimensional structure diagram of an accelerometer according to an embodiment of the present invention;
fig. 2 is a schematic three-dimensional structure diagram of a cover plate according to an embodiment of the present invention;
FIG. 3 is a top view of a sensitive layer provided by an embodiment of the present invention;
FIG. 4 is a sectional view taken along line A-A of FIG. 3;
FIG. 5 is a schematic diagram of the operation of a pendulum-type omni-directional micro-mechanical accelerometer according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of an output circuit provided by an embodiment of the invention;
FIG. 7 is a flow chart of a manufacturing process of a pendulum-type omnidirectional micro-mechanical accelerometer with a dynamic heat source according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of an output circuit provided by an embodiment of the invention;
icon: the device comprises a sensitive layer 1, a substrate layer 2, a middle detection cavity 3, a middle heating cavity 4, a cover plate 5, a groove 6, an omnidirectional movable heat source swinging heater 7, a thermistor 8, a thermistor 9, a thermistor 10, a thermistor 11, a thermistor 12, a thermistor 13, a thermistor 14, a thermistor 15 and an electrode 16.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
Referring to fig. 1-4, the present embodiment provides a pendulum-type omni-directional micro-mechanical accelerometer with a dynamic heat source, which includes a sensitive layer 1, a substrate layer 2 and a cover plate 5, wherein,
an omnidirectional dynamic heat source pendulum heater and eight thermistors are arranged at the central position of the upper surface of the sensitive layer 1;
defining the length and width directions of the rectangular sensitive layer as X and Y directions respectively, and the height direction of the sensitive layer as Z direction; the thermistor is arranged around the sensitive layer in a regular octagon shape by taking the heater as a center; the eight thermistors are arranged oppositely in pairs and used for detecting the omnibearing acceleration;
the omnidirectional moving heat source pendulum heater 7 is suspended at the central position of the sensitive layer 1 through six completely symmetrical semicircular spokes, and a circular middle heating cavity 4 is arranged below the omnidirectional moving heat source pendulum heater; the heater 7 can swing along any azimuth angle in an XOY plane of the sensitive layer 1 besides the z-axis vertical to the sensitive layer;
eight thermistors are distributed around the position of the heater in a regular octagon shape. The thermistor 8 and the thermistor 12 are symmetrically arranged in the left and right directions of the omnidirectional movable heat source pendulum heater 7, the thermistor 10 and the thermistor 14 are symmetrically arranged in the upper and lower directions of the heater, and the thermistor 9, the thermistor 11, the thermistor 13 and the thermistor 15 are symmetrically arranged in the diagonal direction of the sensitive layer; the power-on modes of the omnidirectional moving heat source pendulum heater and the thermistor are constant current; two ends of the omnidirectional moving heat source pendulum heater are covered with symmetrical electrodes 16 along the Y direction to form a moving resistance type heat source;
and a groove is etched in the cover plate 5 and is hermetically connected with the upper surface of the sensitive layer 1.
In this embodiment, as a further technical solution, as shown in fig. 5 and fig. 6, the resistance-type heater 7 is energized with a constant current, the resistance of the heater is energized to generate joule heat, and the joule heat releases heat to the surrounding air to perform heat diffusion, and the temperature field generated by the heat flow is symmetrically distributed between the two thermistors in the same direction. Four thermistors T1 (thermistor 8), T5 (thermistor 12), T3 (thermistor 10), and T7 (thermistor 14) having the same resistance value constitute one acceleration detection unit. The four thermistors T2 (thermistor 9), T6 (thermistor 13), T4 (thermistor 11), and T8 (thermistor 15) having the same resistance value constitute another acceleration detecting unit. Taking one of the acceleration detecting units as an example, there is a linear acceleration a along the x-axis (the line connecting the thermistors T1 and T5)X1When the heat source pendulum moves along the direction of the X axis which is the same as the direction of the acceleration under the action of the acceleration during input, the temperature field generated by hot air flow is asymmetrically distributed, the temperature changes of the two thermistors T1 and T5 in the same direction are opposite, the temperature of the thermistor deflected by the heat source pendulum is higher than that of the thermistor parallel to the thermistor, and the two symmetrical thermistors T1 and T5 generate temperature difference. Thermistors T1 and T5 are used as two bridge arms of a Stefan bridge, and the temperature difference caused by the input acceleration is converted into the change of the resistance of the bridge arms according to the thermal resistance effect, so that the unbalanced voltage V of the bridge proportional to the input acceleration is causedX. The linear acceleration of the X axis can be calculated according to the output voltage, so that the acceleration a in the X direction is sensitiveX1. Similarly, the thermistors T2 and T6, and T4 and T8 constitute another acceleration detecting unit which can sense aX1Or aY1。
As shown in fig. 8, when the plane of the sensor rotates around any azimuth (the azimuth angle is α), the coordinate axes are changed from X, Y, Z to X ', Y', Z ', the angular velocity a to be measured input along the azimuth angle α is projected as a on the coordinate axes X', YX、aY，aX、aYThe relation with the angular velocity a to be measured is as follows:
by measuring aX、aYThe magnitude of the acceleration a input along any azimuth angle can be known. A hereX、aYCan be obtained by measurement by the acceleration detection unit described above. According to a output of the first acceleration detecting unitX、aYCalculating the acceleration input along any azimuth angle by a formula1And (4) showing. Based on a output of the second acceleration detecting unitX1、aY1Calculating the acceleration input along any azimuth angle by formula (1), and using a2And (4) showing. Get a1And a2The average of (a) yields the size of a:
the detection method can avoid errors caused by process reasons to a greater extent and improve the detection precision. The direction of acceleration can be determined by the change in resistance of the eight thermistors, in which quadrant the azimuth angle is.
In this embodiment, as a further technical solution, the cover plate 5 and the substrate layer 2 isolate the gas media of the intermediate heating chamber 4 and the intermediate detection chamber 3 from the outside, so as to form a sealed working system; the height of the middle heating cavity 4 and the middle detection cavity 3 and the depth of the groove 6 in the upper sealing layer are the total cavity height z, and z is more than or equal to 300 mu m and less than or equal to 1000 mu m; the total cavity height in this embodiment is hundreds of microns in magnitude, and natural convection motion of the gas flow in the cavity can be effectively inhibited.
In this embodiment, as a further technical solution, the gas flowing space is increased by increasing the depth of the groove of the cover plate, and the depth of the groove 6 is 2/3 of the height of the cover plate 5.
In this embodiment, as a further technical solution, in order to form a more stable and reliable thin film resistor having a resistance value with a small change with temperature, the heights of the heater and the thermistor on the upper surface of the sensitive layer are 100nm to 1000 nm.
In this embodiment, as a further technical solution, to increase the stability and shock resistance of the sensor, the two pairs of thermistors have the same length, which is 1/6 to 1/5 of the width of the whole sensitive layer.
In this embodiment, as a further technical solution, the heater and the thermistor are each formed by a metal layer composed of a chromium adhesion layer and a platinum layer.
Referring to fig. 7, the specific process flow of the dynamic heat source pendulum type omnidirectional micro mechanical accelerometer disclosed by the invention is as follows:
step (a): a0.5 μm thick silicon dioxide film was thermally oxidized on an N-type (100) single crystal silicon wafer.
Step (b): and photoetching the silicon dioxide film to form structural patterns of the omnidirectional movable heat source pendulum heater and the thermistor.
Step (c): and sputtering a metal layer consisting of a chromium adhesion layer and a platinum layer on the photoresist and the silicon dioxide in sequence by using a magnetron sputtering process.
Step (d): and stripping off the metal layers outside the structure patterns of the omnidirectional moving heat source pendulum heater and the thermistor by adopting an ultrasonic stripping process to form the omnidirectional moving heat source pendulum heater and the thermistor structure.
A step (e): and etching off a part of silicon dioxide by adopting photoetching and wet etching processes.
Step (f): and etching and processing the substrate to form a groove with the depth of 300 mu m by adopting a silicon etching process, so that the omnidirectional moving heat source pendulum heater and the thermistor are suspended and fixed on the sensitive layer through the silicon dioxide film to complete the processing of the sensitive layer.
Step (g): and bonding the cover plate and the sensitive layer by a bonding process to enable the upper surface of the sensitive layer to be positioned in the closed cavity to complete the processing of the sensitive element.
In summary, the invention breaks through the inherent mode of the previous research on the heat flow accelerometer, and provides a dynamic heat source pendulum type omnibearing micro mechanical accelerometer, which enables a heater with a very high temperature gradient to move, and the heater deflects under the action of inertia force to form a large temperature gradient at a thermistor, thereby realizing high-sensitivity output. The omnibearing moving heat source pendulum heater is suspended in the center of the sensitive layer through six completely symmetrical semicircular supporting beams, can realize omnibearing measurement of acceleration, and has high sensitivity and high response speed. The central heater adopts a wind-fire wheel type sensitive structure, so that a relatively long elastic element and a relatively large mass block can be manufactured in a small area, and high inertia force sensitivity is obtained. When the acceleration is input along the carrier around any azimuth angle, the output voltage of the acceleration is averaged and then output, the detection sensitivity is always kept at a constant value, the change caused by the difference of the azimuth angles is avoided, and meanwhile, the quadrant where the acceleration is located and the azimuth angle can be accurately judged. Therefore, the measurement error is small, and the detection accuracy is high. Meanwhile, the micro-accelerometer has the advantages of simple structure and processing technology, extremely low cost, high reliability and excellent vibration and impact resistance, so that the micro-accelerometer can compete with a solid pendulum type micro-mechanical accelerometer in the micro-accelerometer market with medium, low precision and low price. Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (6)
1. A pendulum type omnibearing micro mechanical accelerometer with dynamic heat source is characterized by that it includes base layer, sensitive layer and cover plate, in which,
the sensitive layer comprises a middle heating cavity and a middle detection cavity, and the upper surface of the sensitive layer is provided with an omnidirectional movable heat source swinging heater and four pairs of thermistors;
defining the length and width directions of the accelerometer as X and Y directions respectively, and the height direction of the sensitive layer as Z direction; the heater is suspended at the center of the sensitive layer through six completely symmetrical semicircular spokes, and the thermistors are distributed around the omnidirectional moving heat source swinging heater in a regular octagon shape; the eight thermistors are arranged oppositely in pairs and used for detecting the acceleration in all directions;
the omnidirectional moving heat source swinging heater is suspended at the center of the sensitive layer through six completely symmetrical semicircular spokes, a circular middle heating cavity is arranged below the omnidirectional moving heat source swinging heater, and eight thermistors are distributed around the position of the heater in a regular octagon shape;
the omnidirectional moving heat source swinging heater can swing along a Z axis vertical to the sensitive layer and also can swing along any azimuth angle in an XOY plane where the sensitive layer is located;
the power-on modes of the omnidirectional moving heat source pendulum heater and the thermistor are constant current;
the cover plate and the substrate layer isolate the gas media of the intermediate heating cavity and the intermediate detection cavity from the outside to form a sealed working system; the height of the middle heating cavity and the middle detection cavity and the depth of the groove on the cover plate are the total cavity height z, and z is more than or equal to 300 mu m and less than or equal to 1000 mu m.
2. The dynamic heat source pendulum all-dimensional micromachined accelerometer of claim 1, wherein the depth of the recess of said cover plate is 2/3 of the height of the cover plate.
3. The dynamic heat source pendulum type omni-directional micro-machined accelerometer according to claim 1, wherein the height of the heater and the thermistor is 100nm to 1000 nm.
4. The dynamic heat source pendulum type omni-directional micro-machined accelerometer according to claim 1, wherein the eight thermistors on the upper surface of the sensitive layer have the same length, which is 1/6 to 1/5 of the width of the whole sensitive layer.
5. The dynamic heat source pendulum type omni-directional micro-mechanical accelerometer of claim 1, wherein the heater and the thermistor are both made of metal layers consisting of a chromium adhesion layer and a platinum layer.
6. A method for processing the dynamic heat source pendulum type omnibearing micro-mechanical accelerometer according to any one of claims 1 to 5, characterized by comprising the following specific process flows:
the method comprises the following steps: thermally oxidizing a 0.5 μm thick silicon dioxide film on an N-type (100) single crystal silicon wafer;
step two: photoetching the silicon dioxide film to form structural patterns of an omnidirectional dynamic heat source pendulum heater and a thermistor;
step three: sputtering a metal layer consisting of a chromium adhesion layer and a platinum layer on the photoresist and the silicon dioxide in sequence by a magnetron sputtering process;
step four: stripping off the metal layer outside the all-directional movable heat source pendulum heater and the thermistor structure pattern by adopting an ultrasonic stripping process to form an all-directional movable heat source pendulum heater and a thermistor structure;
step five: etching off a part of silicon dioxide by adopting photoetching and wet etching processes;
step six: a groove with the depth of 300 mu m is formed by corrosion processing by adopting a silicon etching process, so that the omnidirectional moving heat source pendulum heater and the thermistor are suspended and fixed on the sensitive layer through a silicon dioxide film to finish the processing of the sensitive layer;
step seven: and bonding the cover plate and the sensitive layer by a bonding process to enable the upper surface of the sensitive layer to be positioned in the closed cavity to complete the processing of the sensitive element.
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