阅读说明：本技术 一种集成温控的微小型硅压阻式压力传感器及其制造方法 (Integrated temperature control micro-miniature silicon piezoresistive pressure sensor and manufacturing method thereof ) 是由 王新亮 罗芳海 雷中柱 俞骁 于 2021-08-09 设计创作，主要内容包括：本发明涉及一种集成温控的微小型硅压阻式压力传感器及其制造方法,该集成温控的微小型硅压阻式压力传感器包含基板、盖板、恒温管壳、硅压阻式压力传感器芯片、温度传感器芯片和PI加热片；所述恒温管壳设置在基板和盖板之间,且两端分别与基板和盖板固定连接,形成恒温腔室；所述恒温管壳上还设置有导气管；所述硅压阻式压力传感器芯片和温度传感器芯片设置在基板上,且均位于恒温腔室内；所述PI加热片设置在恒温管壳上,用于给恒温腔室加热,使硅压阻式压力传感器芯片温度恒定；本发明不仅能保证硅压阻式压力传感器芯片温度恒定,避免温度波动对压力测量的影响,且结构简单、体积小,能满足压力传感器小型化、低功耗的要求。(The invention relates to an integrated temperature-controlled micro-miniature silicon piezoresistive pressure sensor and a manufacturing method thereof, wherein the integrated temperature-controlled micro-miniature silicon piezoresistive pressure sensor comprises a substrate, a cover plate, a constant-temperature tube shell, a silicon piezoresistive pressure sensor chip, a temperature sensor chip and a PI heating sheet; the constant-temperature pipe shell is arranged between the base plate and the cover plate, and two ends of the constant-temperature pipe shell are fixedly connected with the base plate and the cover plate respectively to form a constant-temperature chamber; the constant temperature pipe shell is also provided with an air duct; the silicon piezoresistive pressure sensor chip and the temperature sensor chip are arranged on the substrate and are both positioned in the constant-temperature cavity; the PI heating sheet is arranged on the constant-temperature tube shell and used for heating the constant-temperature cavity to enable the temperature of the silicon piezoresistive pressure sensor chip to be constant; the silicon piezoresistive pressure sensor chip temperature control device can not only ensure that the temperature of the silicon piezoresistive pressure sensor chip is constant, avoid the influence of temperature fluctuation on pressure measurement, but also has simple structure and small volume, and can meet the requirements of miniaturization and low power consumption of the pressure sensor.)

1. An integrated temperature control micro-miniature silicon piezoresistive pressure sensor is characterized in that: the constant temperature sensor comprises a substrate, a cover plate, a constant temperature tube shell, a silicon piezoresistive pressure sensor chip, a temperature sensor chip and a PI heating plate;

the substrate and the cover plate are arranged in parallel;

the constant-temperature pipe shell is arranged between the base plate and the cover plate, and two ends of the constant-temperature pipe shell are fixedly connected with the base plate and the cover plate respectively to form a constant-temperature chamber; the constant temperature pipe shell is also provided with an air duct communicated with the constant temperature chamber;

the silicon piezoresistive pressure sensor chip and the temperature sensor chip are arranged on the substrate and are both positioned in the constant-temperature cavity, and the leads respectively penetrate through the substrate and extend out of the constant-temperature cavity;

the PI heating sheet is arranged on the constant-temperature tube shell and used for heating the constant-temperature cavity, so that the temperature of the silicon piezoresistive pressure sensor chip is constant.

2. The integrated temperature controlled micro miniature silicon piezoresistive pressure sensor according to claim 1, wherein: the constant temperature tube shell adopts 3D printing technology integration printing shaping.

3. The integrated temperature controlled micro miniature silicon piezoresistive pressure sensor according to claim 2, wherein: the 3D printing material of the constant temperature pipe shell is ceramic or metal material.

4. The integrated temperature controlled micro miniature silicon piezoresistive pressure sensor according to claim 3, wherein: and two ends of the constant-temperature pipe shell are respectively bonded and fixed with the base plate and the cover plate.

5. The integrated temperature controlled micro miniature silicon piezoresistive pressure sensor according to any of the claims 1-4, wherein: and the PI heating sheet is fixed on the constant-temperature pipe shell through adhesion.

6. A manufacturing method of an integrated temperature control micro-miniature silicon piezoresistive pressure sensor is characterized by comprising the following steps: comprises the following steps:

s1, manufacturing a PI heating plate, namely processing by adopting a PI sacrificial layer process to obtain the PI heating plate;

s2, assembling, namely carrying out a mounting process on the substrate, the cover plate, the constant-temperature tube shell, the silicon piezoresistive pressure sensor chip, the temperature sensor chip and the PI heating sheet to obtain the integrated temperature-controlled micro silicon piezoresistive pressure sensor;

and S3, detecting that the air tightness of the integrated temperature control micro-miniature silicon piezoresistive pressure sensor is detected.

7. The method of claim 6, wherein the integrated temperature control micro-miniature silicon piezoresistive pressure sensor comprises: the PI sacrificial layer process comprises the following steps:

s11: spin-coating a layer of photo-etching PI glue on the surface of a silicon wafer, wherein the thickness of the PI glue is 3-20 microns;

s12: sputtering or electroplating a metal layer on the surface of the PI adhesive, wherein the thickness of the metal layer is 150-600 nm;

s13: spin-coating a layer of PI glue on the surface of the metal layer, wherein the thickness of the PI glue is 3-20 microns;

s14: carrying out photoetching and developing on the film;

s15: washing away the exposed metal layer after development by using an ion milling process;

s16: and releasing by utilizing a sacrificial layer technology to form a complete PI heating plate.

8. The method of claim 7, wherein the integrated temperature control micro-miniature silicon piezoresistive pressure sensor comprises: the release by using the sacrificial layer technology is specifically that the whole wafer is placed into PI developing solution to be soaked for 10-60min, and each independent PI heating sheet is released along with the gradual dissolution of the PI sacrificial layer.

9. The method of claim 8, wherein the integrated temperature control micro-miniature silicon piezoresistive pressure sensor comprises: the metal layer is one of gold, nickel and platinum.

10. The method of claim 9, wherein the integrated temperature control micro-miniature silicon piezoresistive pressure sensor comprises: the mounting process adopts epoxy adhesive or silicon rubber adhesive for sealing and bonding.

Technical Field

The invention relates to the technical field of pressure sensors, in particular to an integrated temperature control micro-miniature silicon piezoresistive pressure sensor and a manufacturing method thereof.

Background

The pressure sensors are classified into piezoresistive type, resonant type, capacitive type and the like according to the pressure measurement principle, wherein the silicon piezoresistive pressure sensors are the most widely applied type; the silicon piezoresistive pressure sensor is characterized in that a resistor with a Wheatstone bridge structure is prepared on the surface of a silicon film by diffusion or ion implantation by utilizing the piezoresistive property of diffused silicon, and the resistance voltage of the bridge is changed by sensing the deformation of external pressure through a sensitive film, so that the change of the external pressure is measured.

However, due to the sensitivity of semiconductor physical properties to temperature, the silicon piezoresistive pressure sensor is affected by temperature, so that zero point and sensitivity can drift along with the change of temperature, and the silicon piezoresistive pressure sensor without temperature compensation cannot be applied in most fields, so that in practical application, the temperature compensation is an important component of the silicon piezoresistive pressure sensor; with the development of temperature compensation technology, various temperature compensation methods have appeared, which are mainly divided into two types, namely analog circuit compensation and digital circuit compensation; the analog circuit compensation comprises temperature sensitive devices such as series-parallel resistors, series-parallel diodes or series-parallel thermistors, and the voltage or current applied to a pressure sensor bridge is changed under different temperatures to achieve the compensation effect; the digital compensation technology is that under the control of the singlechip, the outputs of the pressure sensor and the temperature sensor are respectively collected, and the zero point and full-range outputs of the pressure sensor are compensated to different degrees under different temperatures; but the following problems are inevitably caused thereby: 1. the circuit is complex; 2. the reliability is low; 3. the temperature sensitive element or the temperature sensor and the pressure sensor are not consistent in environmental temperature, so that the compensation error is large; 4. the temperature characteristic of each sensor needs to be tested to make accurate compensation, the production process is complex, and the like, the temperature drift problem cannot be solved fundamentally, in addition, the compensation accuracy depends on the accuracy and the algorithm of the temperature sensor, and the compensation accuracy is also influenced by the difference between the ambient temperature of the temperature sensor and the temperature of the pressure chip in many cases.

Therefore, the existing method introduces a temperature control system to maintain the sensor chip in a relatively stable temperature environment, thereby reducing the temperature drift and improving the performance of the sensor in the full temperature range; for example, 201811208601.6 discloses a packaging assembly structure of a silicon piezoresistive pressure sensor, which adopts a three-layer tube-shell structure to realize integrated packaging and assembly of a chip temperature control and multi-range chip composite scheme of the silicon piezoresistive pressure sensor, resulting in a complex structure and a large volume, and failing to meet the requirements of miniaturization and low power consumption of the pressure sensor.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an integrated temperature control micro-miniature silicon piezoresistive pressure sensor and a manufacturing method thereof.

In order to achieve the purpose, the invention adopts the technical scheme that: an integrated temperature control micro silicon piezoresistive pressure sensor comprises a substrate, a cover plate, a constant temperature tube shell, a silicon piezoresistive pressure sensor chip, a temperature sensor chip and a PI heating plate;

the substrate and the cover plate are arranged in parallel;

the constant-temperature pipe shell is arranged between the base plate and the cover plate, and two ends of the constant-temperature pipe shell are fixedly connected with the base plate and the cover plate respectively to form a constant-temperature chamber; the constant temperature pipe shell is also provided with an air duct communicated with the constant temperature chamber;

the silicon piezoresistive pressure sensor chip and the temperature sensor chip are arranged on the substrate and are both positioned in the constant-temperature cavity, and the leads respectively penetrate through the substrate and extend out of the constant-temperature cavity;

the PI heating sheet is arranged on the constant-temperature tube shell and used for heating the constant-temperature cavity, so that the temperature of the silicon piezoresistive pressure sensor chip is constant.

Preferably, the thermostatic cartridge is integrally printed and molded by adopting a 3D printing technology.

Preferably, the 3D printing material of the thermostatic cartridge is a ceramic or metal material.

Preferably, two ends of the thermostatic tube shell are respectively bonded and fixed with the base plate and the cover plate.

Preferably, the PI heating plate is fixed to the thermostatic cartridge by adhesion.

The invention also discloses a manufacturing method of the integrated temperature control micro-miniature silicon piezoresistive pressure sensor, which comprises the following steps:

s1, manufacturing a PI heating plate, namely processing by adopting a PI sacrificial layer process to obtain the PI heating plate;

s2, assembling, namely carrying out a mounting process on the substrate, the cover plate, the constant-temperature tube shell, the silicon piezoresistive pressure sensor chip, the temperature sensor chip and the PI heating sheet to obtain the integrated temperature-controlled micro silicon piezoresistive pressure sensor;

and S3, detecting that the air tightness of the integrated temperature control micro-miniature silicon piezoresistive pressure sensor is detected.

Preferably, the PI sacrificial layer process comprises the following steps:

s11: spin-coating a layer of photo-etching PI glue on the surface of a silicon wafer, wherein the thickness of the PI glue is 3-20 microns;

s12: sputtering or electroplating a metal layer on the surface of the PI adhesive, wherein the thickness of the metal layer is 150-600 nm;

s13: spin-coating a layer of PI glue on the surface of the metal layer, wherein the thickness of the PI glue is 3-20 microns;

s14: carrying out photoetching and developing on the film;

s15: washing away the exposed metal layer after development by using an ion milling process;

s16: and releasing by utilizing a sacrificial layer technology to form a complete PI heating plate.

Preferably, the release by using the sacrificial layer technology is to put the whole wafer into a PI developing solution to be soaked for 10-60min, and each independent PI heating sheet is released along with the gradual dissolution of the PI sacrificial layer.

Preferably, the metal layer is one of gold, nickel and platinum.

Preferably, the mounting process uses an epoxy adhesive or a silicone adhesive for sealing and bonding.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:

1. according to the invention, the PI heating sheet is arranged on the constant-temperature tube shell, so that the temperature of the silicon piezoresistive pressure sensor chip can be ensured to be constant, the influence of temperature fluctuation on pressure measurement can be avoided, the structure is simple, the size is small, and the requirements of miniaturization and low power consumption of the pressure sensor can be met;

2. the PI heating sheet adopts the PI sacrificial layer process, so that the PI heating sheet has the characteristic of being bendable, and therefore the PI heating sheet and the constant-temperature tube shell can be seamlessly combined, the whole surface area is hardly occupied, and the heating efficiency and the temperature control precision are greatly improved;

3. the PI heating plate adopts the PI sacrificial layer process, so that the volume and the cost of the heater can be obviously reduced.

Drawings

The technical scheme of the invention is further explained by combining the accompanying drawings as follows:

FIG. 1 is a schematic structural diagram of an integrated temperature control micro-miniature silicon piezoresistive pressure sensor according to the present invention;

FIG. 2 is a flow chart of the PI heating plate processing technology.

Wherein: 1. a substrate; 2. a cover plate; 3. a constant temperature pipe shell; 4. a silicon piezoresistive pressure sensor chip; 5. a temperature sensor chip; 6. a PI heating plate; 7. a thermostatic chamber; 8. an air duct; 9. and (7) leading wires.

Detailed Description

The invention is described in further detail below with reference to the figures and the embodiments.

The first embodiment is as follows:

FIG. 1 is an integrated temperature control micro-miniature silicon piezoresistive pressure sensor, which comprises a substrate 1, a cover plate 2, a constant temperature tube shell 3, a silicon piezoresistive pressure sensor chip 4, a temperature sensor chip 5 and a PI heating plate 6; the base plate 1 and the cover plate 2 are arranged in parallel; the constant-temperature pipe shell 3 is arranged between the base plate 1 and the cover plate 2, and two ends of the constant-temperature pipe shell are respectively bonded and fixedly connected with the base plate 1 and the cover plate 2 to form a constant-temperature chamber 7; the thermostatic tube shell 3 is also provided with an air duct 8 communicated with the thermostatic chamber 7; the silicon piezoresistive pressure sensor chip 4 and the temperature sensor chip 5 are arranged on the substrate 1 and are both positioned in the constant temperature chamber 7, and the leads 9 respectively penetrate through the substrate 1 and extend out of the constant temperature chamber 7; and the PI heating sheet 6 is fixedly bonded on the constant temperature tube shell 3 and used for heating the constant temperature chamber 7 so as to ensure that the temperature of the silicon piezoresistive pressure sensor chip 4 is constant.

When in work: the temperature sensor chip 5 is used for measuring the temperature of the silicon piezoresistive pressure sensor chip 4, and the heating current of the PI heating sheet 6 is controlled according to the difference value between the measured temperature of the temperature sensor chip 5 and a preset standard temperature value so as to maintain the silicon piezoresistive pressure sensor chip 4 at a constant temperature and avoid the influence of temperature fluctuation on pressure measurement; in order to ensure that the temperature measured by the temperature sensor chip 5 is as same as the temperature of the silicon piezoresistive pressure sensor chip 4 as possible, the temperature sensor chip 5 and the silicon piezoresistive pressure sensor chip 4 are packaged on the surface of the same substrate 1 as close as possible.

Further, the constant temperature tube 3 adopts the integration of 3D printing technique to print the shaping, can promote the integration technique and the temperature field distribution of constant temperature tube 3, avoids constant temperature tube 3 to be heated and produces stress deformation to influence the whole precision of showing.

Further, the 3D printing material of the constant temperature tube shell 3 is a material with good heat conductivity such as ceramic or metal, so that the constant temperature tube shell 3 has a good heat conduction effect.

The invention also discloses a manufacturing method of the integrated temperature control micro-miniature silicon piezoresistive pressure sensor, which comprises the following steps:

s1, manufacturing a PI heating plate, namely processing by adopting a PI sacrificial layer process to obtain a PI heating plate 6;

s2 assembling, namely, carrying out mounting technology on the substrate 1, the cover plate 2, the constant-temperature tube shell 3, the silicon piezoresistive pressure sensor chip 4, the temperature sensor chip 5 and the PI heating sheet 6 by adopting an epoxy adhesive or a silicon rubber adhesive to obtain the integrated temperature-controlled miniature silicon piezoresistive pressure sensor;

and S3, detecting that the air tightness of the integrated temperature control micro-miniature silicon piezoresistive pressure sensor is detected.

Further, as shown in fig. 2, the PI sacrificial layer process includes the following steps:

s11: spin-coating a layer of photo-lithograpable PI (polyimide) glue on the surface of a monocrystalline silicon wafer, wherein the thickness is 3-20 microns;

s12: sputtering or electroplating a layer of gold with the thickness of 150-600 nm on the surface of the PI glue to form a metal layer;

s13: spin-coating a layer of PI (polyimide) glue on the surface of the metal layer, wherein the thickness of the PI glue is 3-20 micrometers;

s14: carrying out photoetching and developing on the film;

s15: washing away the exposed metal layer after development by using an ion milling process;

s16: the complete PI heating plate 6 is released by using a sacrificial layer technique.

Further, the release by using the sacrificial layer technology is specifically to put the whole wafer into a PI developing solution to be soaked for 10-60min, and each independent PI heating plate 6 is released along with the gradual dissolution of the PI sacrificial layer.

Example two:

the difference from the first implementation is that: in step S12, a layer of nickel with a thickness of 150-600 nm is sputtered or electroplated on the PI glue surface to form a metal layer.

Example three:

the difference from the first implementation is that: in step S12, a layer of platinum with a thickness of 150-600 nm is sputtered or electroplated on the PI glue surface to form a metal layer.

Example four:

the difference from the first implementation is that: in step S1, a LIFT-OFF process is used for processing to obtain the PI heating sheet 6.

The integrated temperature-controlled micro-miniature silicon piezoresistive pressure sensor obtained in the embodiments 1-4 has the following advantages:

1. according to the invention, the PI heating sheet is arranged on the constant-temperature tube shell, so that the temperature of the silicon piezoresistive pressure sensor chip can be ensured to be constant, the influence of temperature fluctuation on pressure measurement can be avoided, the structure is simple, the size is small, and the requirements of miniaturization and low power consumption of the pressure sensor can be met;

2. the PI heating sheet adopts the PI sacrificial layer process, so that the PI heating sheet has the characteristic of being bendable, and therefore the PI heating sheet and the constant-temperature tube shell can be seamlessly combined, the whole surface area is hardly occupied, and the heating efficiency and the temperature control precision are greatly improved;

3. the PI heating plate adopts the PI sacrificial layer process, so that the volume and the cost of the heater can be obviously reduced.

The above is only a specific application example of the present invention, and the protection scope of the present invention is not limited in any way. All the technical solutions formed by equivalent transformation or equivalent replacement fall within the protection scope of the present invention.