Temperature and pressure integrated sensor with flat membrane characteristic and back bottom pressure bearing function and preparation method of temperature and pressure integrated sensor

Abstract

The invention discloses a temperature and pressure integrated sensor with flat membrane characteristics and back bottom pressure bearing and a preparation method thereof, and belongs to the field of microsensors, the sensor comprises a substrate and bonding glass which are in bonding connection, a through hole is formed in the bonding glass, and the part, located on the inner side of the through hole, of the substrate is divided into a sensitive membrane; a first piezoresistor, a second piezoresistor, a third piezoresistor, a fourth piezoresistor, a temperature-sensitive resistor and a doped lead are arranged on the substrate, and the temperature-sensitive resistor is arranged in a bonding area; the first piezoresistor, the second piezoresistor, the third piezoresistor and the fourth piezoresistor are located on the edge of a pressure bearing area and are symmetrically arranged in the circumferential direction. A metal electrode is arranged on each doped lead; the first piezoresistor, the second piezoresistor, the third piezoresistor, the fourth piezoresistor, the temperature-sensitive resistor and all the metal electrodes are connected to form a Wheatstone measuring circuit. According to the invention, the zero temperature drift in a wide temperature range is smaller, and the pressure measurement precision error in the wide temperature range is smaller.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro sensors, and in particular relates to a temperature-pressure integrated sensor with a flat film characteristic and back-end pressure bearing, and a preparation method thereof. Background Art

[0002] The application field of piezoresistive pressure sensors based on micro-electromechanical systems (MEMS) technology is very broad, involving aerospace, petrochemical, industrial control, power and medical fields. Temperature, as an industrial basic parameter, is also important in the above fields. As the requirements for industry intelligent sensors, equipment status monitoring, multi-parameter fusion and analysis become higher and higher, temperature-pressure integrated, temperature-pressure composite and even temperature-pressure integrated sensors are an important form of multi-parameter integrated sensors.

[0003] Temperature and pressure integrated sensors usually refer to temperature sensors and pressure sensors that are packaged separately and then integrated as a whole. The two parameters are essentially two independent sensors; temperature and pressure composite sensors usually refer to temperature sensitive chips and pressure sensitive chips that are relatively independent and integrated during packaging. Their volume and mass are further optimized compared to temperature and pressure integrated sensors. Temperature and pressure integrated sensors are developed based on the integration of the above two sensors, with the temperature and pressure sensitive units directly integrated on the core, that is, two parameters, the same chip, and the same packaging form of the sensor. It is a further improved form of the sensor that measures both temperature and pressure parameters at the same time.

[0004] At present, most of the temperature and pressure composite sensors are discrete chips. The temperature sensor and the pressure sensor are manufactured separately and packaged together, which makes it impossible to reduce the package volume and weight, and the measurement is limited in some special environments of aerospace. There are very few temperature and pressure integrated sensors integrated in the core chip, and most temperature sensors are made of platinum resistors. However, the annealing temperature of platinum resistors to form good performance is relatively high, which is close to the annealing temperature of the sensor to form piezoresistance. This leads to the inability of the temperature sensor and the pressure sensor to achieve performance coupling, and the pressure measurement accuracy and temperature measurement accuracy cannot be improved at the same time. Secondly, the pressure measurement accuracy of the existing temperature and pressure integrated sensors is insufficient, the zero point temperature drift is large, and they are rarely resistant to external interference. Due to their huge advantages in volume and quality, temperature and pressure integrated sensors are in urgent need in important fields such as aerospace. At the same time, for the temperature and pressure integrated solution, facing the same medium and the same measuring point, the temperature parameter can also be used as a temperature compensation of the pressure parameter to provide reference information and improve the pressure measurement accuracy.

[0005] Therefore, it is necessary to design an integrated sensor that can meet the simultaneous measurement of temperature and pressure in the aerospace field. While ensuring the measurement of temperature and pressure parameters, it can meet the use requirements of special fields by further reducing the volume and mass of the sensor. Summary of the invention

[0006] In order to overcome the technical deficiencies of existing integrated temperature-pressure and temperature-pressure composite sensors, the purpose of the present invention is to provide a temperature-pressure integrated sensor with flat membrane characteristics and back pressure bearing and a preparation method thereof, which can be used to achieve simultaneous and accurate measurement of pressure and temperature parameters.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A temperature-pressure integrated sensor with flat film characteristics and back-end pressure, comprising a substrate and a bonding glass that are bonded together, wherein a through hole is provided on the bonding glass, and the substrate portion located inside the through hole is a sensitive membrane; a first varistor, a second varistor, a third varistor, a fourth varistor, a temperature-sensitive resistor and a plurality of doped leads are arranged on the substrate, and the temperature-sensitive resistor is arranged in a bonding area; the first varistor, the second varistor, the third varistor and the fourth varistor are located at the edge of the pressure-bearing area and are arranged symmetrically in the circumferential direction; a metal electrode is respectively provided on each doped lead; the first varistor, the second varistor, the third varistor, the fourth varistor, the temperature-sensitive resistor and all the metal electrodes are connected to form a Wheatstone measurement circuit.

[0009] Furthermore, the orthographic projection of the metal electrode is located within the area covered by the doped lead where the metal electrode is located.

[0010] Furthermore, the substrate is in the form of an integral flat film.

[0011] Furthermore, the structure of the temperature-sensitive resistor is the same as that of the varistor.

[0012] Furthermore, the substrate is prepared by using SOI silicon wafer.

[0013] Furthermore, the metal electrode is prepared using a titanium, platinum, gold material system or a titanium, aluminum material system.

[0014] A method for preparing a temperature-pressure integrated sensor with flat film characteristics and back pressure bearing comprises the following steps:

[0015] S1, heavily doping the front side of the SOI silicon wafer with boron ions to obtain a heavily doped region with boron ions, annealing the entire SOI silicon wafer, and then etching a first varistor, a second varistor, a third varistor, a fourth varistor, a temperature-sensitive resistor, and a doped lead in the heavily doped region with boron ions;

[0016] S2, preparing an insulating layer in the non-metal electrode area on the front side of the silicon wafer, preparing a metal electrode in the metal electrode area, and then annealing, so that the doped lead area and the metal electrode are connected to conduct a stable electrical signal, thereby obtaining a pressure core;

[0017] S3, bonding the pressure core to the bonding glass with holes punched;

[0018] S4. Thinning the entire surface of the SOI silicon wafer to the designed sensitive membrane thickness to form a sensitive membrane.

[0019] Furthermore, in step S1, the doping amount is 5e 15 ~1e 16 atms / cm 2 .

[0020] Furthermore, in step S2, a metal electrode is prepared by evaporation or sputtering.

[0021] Furthermore, in step S3, during bonding, the entire SOI silicon wafer is bonded.

[0022] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0023] 1) The present invention removes the metal lead area and uses the doped area as a low-resistance lead. It is only necessary to make a metal electrode on the doped area to lead out the electrical signal. This design can prepare the varistor strip and the doped lead in the same process, simplifying the process flow; at the same time, compared with the conventional method of preparing a small ohmic contact area, that is, a small heavily doped area and then preparing a metal lead and a metal electrode, this large doped area is used as a lead structure. Since the contact area between the metal electrode and the heavily doped area is larger, firstly, it is less likely to form defects during metal preparation, and secondly, a smaller contact resistance can be formed when the metal contacts the doped lead, which improves the quality of the electrical signal transmitted between the metal and the semiconductor, reduces the transmission loss of the electrical signal, and has a smaller zero-point temperature drift in a wide temperature range. After adding a voltage input to the sensor, the electrical output is more stable; as the temperature rises, the resistance value of the metal and the semiconductor contact of the doped area changes very little, making the pressure measurement accuracy error in a wide temperature range smaller.

[0024] 2) Thermistors and varistors are prepared in the same step, which simplifies the process flow. At the same time, since thermistors are also made with heavy doping, in order to eliminate the influence of the central stress area on them, the thermistor is set in the non-stress area, and the layout direction of the thermistor is in the direction of sensitivity coefficient 0. This design simplifies the process flow. At the same time, since thermistors are made with heavy doping, their resistance temperature coefficient changes less with temperature, which is conducive to improving the temperature measurement accuracy. The designed position is close to the varistor, realizing the in-situ measurement of temperature.

[0025] 3) The sensor provided by the present invention is back-pressure-bearing. The diaphragm is not prepared by conventional back-etching back cavity, but by grinding the whole surface after the sensor device layer is prepared. This whole-surface grinding can prepare a diaphragm with a smooth surface, realizing the preparation of wafer-level back-pressure-bearing chips. The existing back-pressure-bearing is usually prepared by micro-nano manufacturing process and the diaphragm is prepared by etching. In the subsequent bonding process, each chip needs to be individually anodic bonded.

[0026] 4) The present invention performs temperature and pressure integration on a back-end flat-film pressure-bearing structure, and the size of the prepared sensor can be controlled at about 3 mm, which is smaller than the existing flat-film back-end pressure-bearing structure. This sensor is packaged in an inverted manner, with the back facing outward, and the glass is packaged inside the tube shell. The prepared varistors are not in direct contact with the external environment, thereby increasing the anti-interference ability in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a temperature-pressure integrated sensor with flat film characteristics and back pressure in Example 1;

[0028] Figure 2 A schematic side view of a temperature-pressure integrated sensor with flat film characteristics and back pressure in Example 1;

[0029] Figure 3 A three-dimensional schematic diagram of a temperature-pressure integrated sensor with flat film characteristics and back pressure in Example 1;

[0030] Figure 4 The basic circuit diagram of the temperature and pressure integrated sensor in Example 1 consisting of a Wheatstone pressure measurement bridge and a temperature measuring resistor;

[0031] Figure 5 Schematic diagram of the bonding connection structure between the glass ring and the SOI core in Example 1;

[0032] Figure 6 is a schematic diagram of a glass ring with a square hole in Example 1;

[0033] Figure 7 A flow chart of the sensor preparation method provided for Example 1;

[0034] Figure 8 A schematic diagram of a core structure of a circular membrane temperature-pressure integrated sensor with flat membrane characteristics and back pressure in Example 2;

[0035] Fig. 9 Schematic diagram of the circular glass ring in Example 2.

[0036] In the figure, 1 is a substrate; 2 is a first varistor; 3 is a temperature-sensitive resistor; 4 is a second varistor; 5 is a third varistor; 6 is a fourth varistor; 7 is a sensitive membrane; 8 is a doped lead; 9 is a metal electrode; 10 is a bonding glass; and 11 is a metal lead. DETAILED DESCRIPTION

[0037] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0039] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be another element centered thereon. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be another element centered thereon at the same time. The terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc. used herein indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0041] Reference Figure 1A temperature and pressure integrated sensor core with a flat membrane structure and back pressure, comprising a substrate 1 and a bonding glass 10 connected by bonding, the bonding glass 10 constituting a supporting structure for subsequent core packaging, the portion of the substrate 1 within the closed curve formed at the intersection of the inner cavity of the bonding glass 10 and the profile of the substrate 1 constituting a square sensitive membrane 7, the sensitive membrane 7 being the pressure-bearing area; the substrate 1 is in the form of an integral flat membrane; the substrate 1 is provided with a first varistor 2, a second varistor 4, a third varistor 5, a fourth varistor 6, a temperature-sensitive resistor 3 and six doped leads 8 constituting the first varistor 2, the second varistor 4, the third varistor 5 and the fourth varistor 6 of a Wheatstone bridge, which are located at the edge of the pressure-bearing area and are arranged symmetrically in the circumferential direction; the six doped leads 8 are respectively provided with six metal electrodes 9, namely, metal electrode a, metal electrode b, metal electrode c, metal electrode d, metal electrode e and metal electrode f. The orthographic projections of the metal electrode a, the metal electrode b, the metal electrode c, the metal electrode d, the metal electrode e and the metal electrode f are located within the area covered by the doped lead 8 where they are located.

[0042] The temperature-sensitive resistor 3 is located in the non-pressure-bearing area outside the sensitive diaphragm 7, one end of which is connected to the metal electrode e, and the other end of which is connected to the metal electrode f. The temperature-sensitive resistor 3, the doped lead 8, the metal electrode e and the metal electrode f work together to achieve temperature measurement.

[0043] The substrate 1 is made of SOI silicon wafer, with a top silicon thickness of 300-600 nm. The material properties of the SOI substrate are used to improve the temperature operating range and sensor accuracy of the pressure sensor.

[0044] The bonding glass 10 and all the varistors, thermistors 3 and the doped leads 8 are located on the top silicon layer of the substrate 1. The inner ring bottom edge of the bonding glass 10 forms the boundary of the sensitive diaphragm 7. The first varistor 2, the second varistor 4, the third varistor 5 and the fourth varistor 6 are located in the stress concentration area of ​​the sensitive diaphragm 7.

[0045] Furthermore, the sensitive membrane 7, ie, the inner ring of the bonding glass, is rectangular in shape.

[0046] Furthermore, the shape of the sensitive diaphragm 7 may also be other shapes such as a circle. When the sensitive diaphragm 7 is a circle, the first varistor 2, the second varistor 4, the third varistor 5 and the fourth varistor 6 are respectively located at four equal parts of the inner edge of the circular diaphragm.

[0047] The non-top silicon side of the SOI substrate serves as the pressure-bearing surface, forming a back-to-bottom pressure-bearing solution. The temperature-sensitive resistor 3 is located in the non-pressure-bearing non-deformation zone, and the substrate is used as an armored protective layer. While measuring the temperature parameter, it provides an in-situ on-chip temperature reference for temperature compensation of pressure measurement.

[0048] The temperature-sensitive resistor 3 is formed by a doped resistor strip having the same structure and process as the varistor.

[0049] Furthermore, the temperature-sensitive resistor 3 can also be prepared by etching in steps instead of etching together with the varistor, so that a larger doping dose than the varistor can be designed, and the doping dose range can be between 5e 15 ~1e 16 atms / cm 2 , since the greater the doping dose, the smaller the resistance changes with temperature, thus achieving good control of the temperature coefficient of resistance TCR.

[0050] Metal electrodes a, b, c, d, e and f are all located on the doped wires 8 of the sensitive film 7, i.e., the inner side of the bonding glass cavity. The metal electrodes are independent of each other, and are connected to the doped wires 8. The doped wires 8 are connected to each other through the first varistor 2, the second varistor 4, the third varistor 5, the fourth varistor 6, and the temperature-sensitive resistor 3, forming an on-chip integrated Wheatstone measurement circuit.

[0051] Furthermore, the metal electrode 9 may be a titanium, platinum, gold material system, or a titanium, aluminum material system.

[0052] Furthermore, the doped lead 8 is obtained by boron ion heavy doping and etching process.

[0053] The following are specific embodiments. It should be noted that these embodiments are preferred examples of the present invention and are used for those skilled in the art to understand the present invention, but the present invention is not limited to these embodiments.

[0054] Example 1

[0055] Reference Figures 1 to 6, a temperature-pressure integrated sensor with flat film characteristics and back-to-bottom pressure, including substrate 1, varistor 2, temperature-sensitive resistor 3, varistor 4, varistor 5, varistor 6, doped lead 8, metal electrode 9 and bonding glass 10. The substrate 1 is a double-sided polished flat film structure, and the top silicon thickness is 300nm-600nm; the beginning of the bonding glass 10 has a rectangular hole, and the closed curve formed at the intersection of the rectangular hole and the substrate 1 constitutes a square sensitive diaphragm 7. When the sensitive diaphragm 7 is deformed under pressure, the resistance values ​​of the first varistor 2, the second varistor 4, the third varistor 5 and the fourth varistor 6 change to form an electrical output signal of the pressure parameter; the temperature-sensitive resistor 3 is located in the non-stress deformation zone, and its resistance value changes with the change of the sensor temperature, and the temperature measurement is realized by measuring the resistance change of the temperature-sensitive resistor 3; the bonding glass 10 is connected to the substrate 1 through anodic bonding, and the four varistors are located in the stress concentration zone of the sensitive diaphragm 7. The temperature-sensitive resistor 3, four varistors, doped wires 8 and bonding glass 10 are all located on the top silicon side of the substrate 1, as shown in FIG. Figure 3 The first varistor 2, the second varistor 4, the third varistor 5 and the fourth varistor 6 constitute the four resistors required for the Wheatstone bridge in the pressure sensitive unit, and are interconnected through the doped lead 8 to form a Wheatstone measurement circuit, as shown in FIG. Figure 4 shown.

[0056] The back side of the temperature and pressure sensor core bears the pressure of the measured medium. Figure 5 As shown in the figure, after the sensitive diaphragm 7 is subjected to pressure and deformation, the first piezoresistors 2, 4, 5 and 6 are subjected to symmetrical tension or pressure respectively, resulting in resistance changes, which are reflected in the Wheatstone measurement circuit to form an electrical signal output corresponding to the pressure. The temperature-sensitive resistor 3 is in the non-stress deformation zone, and its resistance is not affected by pressure changes, but only depends on temperature changes.

[0057] Reference Figures 1 to 4 A plurality of doped leads 8 are formed by overall ion implantation and heavy doping of the top silicon layer of SOI, and are isolated from each other by etching to block the varistors that should not be connected, thereby forming a Wheatstone circuit. Metal electrodes of a titanium-platinum material system are prepared on the doped leads, and ohmic contact is achieved between the contact interface between the doped leads and the metal electrodes by nitrogen annealing to conduct electrical signals.

[0058] Reference Figures 1 to 5 The temperature-sensitive resistor 3 adopts the same structure and material as the first varistor 2 , the second varistor 4 , the third varistor 5 and the fourth varistor 6 .

[0059] Bonding glass 10 Figure 6 As shown, the inner ring is a rectangle, and the shape of the outer ring is not specifically restricted.

[0060] The method for preparing the pressure sensor of Example 1 comprises the following steps:

[0061] S1, such as Figure 7 As shown in (1), a piece of SOI silicon wafer is selected, cleaned and dried, and then heavily doped with boron ions on the entire front surface of the SOI silicon wafer by ion implantation, with a doping dose of 6e 14 ~5e 15 atms / cm 2 , the resistance values ​​of sensitive resistors of different ranges (sensitive resistors include thermistor 3 and all varistors.) can be the same, so the injection dose is the same. After the injection is completed, the entire SOI silicon wafer is annealed in a high-temperature nitrogen atmosphere at 350-550°C, and then the first varistor 2, the second varistor 4, the third varistor 5, the fourth varistor 6, the thermoresistor 3 and the doped lead 8 are etched in the heavily boron ion doped area. The doped lead 8 area uses the same doping dose as the varistor and is square or rectangular. In order to minimize the resistance value and at the same time lead out the signal of the thermoresistor, the doped lead shape corresponding to the metal electrode e is two large rectangles with a shorter small rectangle in the middle. According to the nature of the square resistance formed by doping, the resistance of this area is only tens of ohms, which can be ignored compared to the thousands of ohms of the varistor, and can stably conduct electrical signals. Thermistor 3 and all varistors are prepared at the same time. The structure of thermistor 3 is consistent with that of the varistor. The difference is that the arrangement direction of the varistor is the crystal direction with a sensitivity of 0, that is, there will be no change in resistance after being subjected to stress, and it will not affect the Wheatstone measurement circuit composed of the varistor. In addition, the position of thermistor 3 is arranged in the bonding area. After bonding, thermistor 3 will not be affected by the stress generated by the sensitive diaphragm. The resistance value formed by thermistor within the selected doping dosage range tends to change linearly with temperature changes, which is more conducive to accurate in-situ temperature measurement.

[0062] S2, such as Figure 7 As shown in (2), a nanometer-scale insulating layer is prepared on the non-metallic electrode area on the front side of the silicon wafer where the sensitive resistor has been prepared, and a metal electrode 9 is prepared on the metal electrode area by evaporation or sputtering. Then, nitrogen annealing is performed in an annealing furnace to connect the doped lead area and the metal electrode to conduct a stable electrical signal, thereby obtaining a pressure core.

[0063] S3, such as Figure 7 As shown in (3), the pressure core is bonded to the bonding glass 10 with holes drilled in it. The material of the bonding glass 10 is BF33. The bonding environment is a vacuum environment below 1e-4Pa. The bonding unit is the entire wafer, rather than bonding each pressure core individually.

[0064] S4, such as Figure 7As shown in (4), the entire bonded wafer is ground and polished, and the entire surface of the SOI flat film substrate 1 is thinned to the designed sensitive film thickness to form the sensitive film 7, instead of using a complex photolithography and then etching method. The wafer is diced to obtain a single temperature-pressure integrated sensor core.

[0065] Example 2

[0066] Reference Figures 8 to 9 , a temperature and pressure integrated sensor with flat film characteristics and back pressure, based on Example 1, the difference between this embodiment and Example 1 is that the structures of the bonding glass 10 and the doped lead 8 are different. A circular through hole is opened on the bonding glass 10, and correspondingly, the sensitive membrane 7 is circular to meet different subsequent packaging requirements; in this embodiment, there are 10 doped leads 8, and the first varistor 2, the second varistor 4, the third varistor 5, the fourth varistor 6 and the temperature-sensitive resistor 3 are respectively connected with a doped lead 8, the doped lead 8 is very small, and is connected to the metal lead 11, and then connected to the metal electrode 9, there are six metal electrodes a, b, c, d, e, and f, the shape of the metal lead 11 is a long rectangular strip with a bend, and the material of the metal electrode is consistent with that of the metal lead; the core dynamic characteristics are differentiated from the rectangular diaphragm to meet different dynamic characteristics requirements.

[0067] Reference Figures 8 to 9 The small square areas at both ends of the varistor are doped leads 8, which are used to contact with the metal to form an electrical connection, and a metal lead 11 is prepared on the area to form an electrical connection. The metal material is aluminum or titanium platinum.

[0068] The term "consisting of" describing a combination shall include the identified elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe a combination of elements, ingredients, parts or steps herein also contemplates embodiments that consist essentially of these elements, ingredients, parts or steps. By using the term "may", it is intended to illustrate that any of the attributes described that "may" be included are optional.

[0069] Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "an" used to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0070] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the foregoing claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A temperature and pressure integrated sensor with flat film characteristics and back pressure, characterized in that: The invention comprises a substrate (1) and a bonding glass (10) which are bonded to each other, wherein a through hole is provided on the bonding glass (10), and a portion of the substrate (1) located inside the through hole is a sensitive film (7); a first varistor (2), a second varistor (4), a third varistor (5), a fourth varistor (6), a temperature-sensitive resistor (3) and a plurality of doped leads (8) are arranged on the substrate (1), and the temperature-sensitive resistor (3) is arranged in a bonding area; the first varistor (2), the second varistor (4), the third varistor (5) and the fourth varistor (6) are located at the edge of the pressure-bearing area and are arranged symmetrically in the circumferential direction; a metal electrode (9) is provided on each doped lead (8); the first varistor (2), the second varistor (4), the third varistor (5), the fourth varistor (6), the temperature-sensitive resistor (3) and all the metal electrodes (9) are connected to form a Wheatstone measurement circuit.

2. The temperature and pressure integrated sensor with flat film characteristics and back pressure according to claim 1, characterized in that: The orthographic projection of the metal electrode (9) is located within the area covered by the doped lead (8) where the metal electrode (9) is located.

3. The temperature and pressure integrated sensor with flat film characteristics and back pressure according to claim 1, characterized in that: The substrate (1) is in the form of an integral flat film.

4. The temperature and pressure integrated sensor with flat film characteristics and back pressure according to claim 1, characterized in that: The temperature-sensitive resistor (3) has the same structure as the varistor.

5. The temperature and pressure integrated sensor with flat film characteristics and back pressure according to claim 1, characterized in that: The substrate (1) is prepared using an SOI silicon wafer.

6. The temperature and pressure integrated sensor with flat film characteristics and back pressure according to claim 1, characterized in that: The metal electrode (9) is prepared using a titanium, platinum, gold material system or a titanium, aluminum material system.

7. A method for preparing a temperature-pressure integrated sensor with flat film characteristics and back pressure, characterized in that: The following steps are involved: S1, heavily doping the front side of the SOI silicon wafer with boron ions to obtain a heavily doped region with boron ions, annealing the entire SOI silicon wafer, and then etching a first varistor (2), a second varistor (4), a third varistor (5), a fourth varistor (6), a temperature-sensitive resistor (3), and a doped lead (8) in the heavily doped region with boron ions; S2, preparing an insulating layer in the non-metallic electrode area on the front side of the silicon wafer, preparing a metal electrode (9) in the metal electrode area, and then annealing to connect the doped lead area and the metal electrode to conduct a stable electrical signal, thereby obtaining a pressure core; S3, bonding the pressure core to the bonding glass (10) with holes punched therein; S4, thinning the entire surface of the SOI silicon wafer to the designed thickness of the sensitive membrane to form a sensitive membrane (7).

8. The method for preparing a temperature-pressure integrated sensor with flat film characteristics and back pressure according to claim 7, characterized in that: In step S1, the doping amount is 5e 15 ~1e 16 atms / cm 2 .

9. The method for preparing a temperature-pressure integrated sensor with flat film characteristics and back pressure bearing according to claim 7, characterized in that: In the step S2, a metal electrode (9) is prepared by evaporation or sputtering.

10. The method for preparing a temperature-pressure integrated sensor with flat film characteristics and back pressure according to claim 7, characterized in that: In the step S3, during bonding, the entire SOI silicon wafer is bonded.

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