CN110749394A - High-reliability pressure sensor - Google Patents
High-reliability pressure sensor Download PDFInfo
- Publication number
- CN110749394A CN110749394A CN201911148984.7A CN201911148984A CN110749394A CN 110749394 A CN110749394 A CN 110749394A CN 201911148984 A CN201911148984 A CN 201911148984A CN 110749394 A CN110749394 A CN 110749394A
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- substrate
- chip
- glass
- pressure sensor
- silicon body
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/02—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning
- G01L9/06—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning of piezo-resistive devices
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/0032—Packages or encapsulation
- B81B7/007—Interconnections between the MEMS and external electrical signals
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/18—Measuring force or stress, in general using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B2201/00—Specific applications of microelectromechanical systems
- B81B2201/02—Sensors
- B81B2201/0264—Pressure sensors
Abstract
The invention relates to the technical field of sensors, in particular to a high-reliability pressure sensor which comprises a chip, wherein the chip comprises a silicon body and glass, the back surface of the glass is provided with a groove, so that a vacuum cavity is formed between the glass and the silicon body, a sensitive film and a bonding pad are arranged on the front surface of a front piezoresistor silicon body in the vacuum cavity, the chip is arranged on a substrate, the back surface of the substrate is provided with an air inlet, the substrate is provided with a shell, the shell is externally and plastically packaged with a plastic part, the air inlet penetrates through the plastic part and is communicated with the outside air, and the substrate is also provided with an outgoing terminal.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a high-reliability pressure sensor.
Background
The existing MEMS pressure sensor has become a mainstream product in the market due to its advantages of high process consistency, high precision, low cost, etc. However, the conventional MEMS pressure sensor, especially the absolute pressure sensor, has a pressed surface on the same side as the bonding pad due to the limitation of the chip structure, and in order to ensure that the bonding pad, the gold wire, and other elements are not affected by the measured medium, we usually use glue for sealing protection. However, such a method is only suitable for testing a conventional gas medium, and in some severe testing environments or when a corrosive medium needs to be tested, the conventional MEMS pressure sensor cannot ensure long-term reliability and stability, and the protective adhesive is easily corroded or the product wiring is easily damaged, so that the testing precision is reduced, the package is damaged, and the safety and reliability of the pressure sensor, the testing precision and the service life are seriously reduced.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a high-reliability pressure sensor, and aims to solve the technical problem of how to design a pressure sensor which can be used in a severe environment and has high reliability and high safety.
In order to solve the technical problems, the technical scheme provided by the invention is as follows: a high-reliability pressure sensor comprises a chip, wherein the chip comprises a silicon body and glass, the back surface of the silicon body is of a silicon cup structure, the back surface of the glass is arranged on the front surface of the silicon body in a bonding mode, a groove is formed in the back surface of the glass, a vacuum cavity is formed between the glass and the silicon body, a sensitive film and a front surface piezoresistor are arranged in the vacuum cavity, the sensitive film is arranged on the front surface of the silicon body in a bonding mode, a bonding pad is further arranged on the front surface of the silicon body, and the bonding pad is located;
the chip is arranged on the substrate, the back of the substrate is provided with an air inlet, and the air inlet is over against the silicon cup structure on the back of the silicon body;
the substrate is provided with a shell, the upper surface of the substrate and the chip are wrapped by the shell, a plastic part is plastically encapsulated outside the shell, and the air inlet hole penetrates through the plastic part and is communicated with the outside air;
the substrate is also provided with a leading-out terminal, and the leading-out terminal is in matched butt joint with an external circuit terminal.
Further, the substrate is made of ceramic.
Further, the substrate and the chip are fixedly connected in a sintering adhesion mode.
Further, the plastic part is injected on the shell in an integral injection molding mode.
The beneficial effect that this technical scheme brought is: the chip in the high-reliability pressure sensor enables a measured medium to be in contact with a silicon cup structure part positioned on the back of a silicon body through a back pressure test working mode, a sensitive film and a front piezoresistor in a vacuum cavity are protected, a PAD is arranged on the front of the silicon body and positioned outside glass, so that the whole body only keeps a PAD part exposed, the chip is ensured to be used under severe environmental conditions or other occasions with corrosive gas and liquid, the requirement of high reliability is met, the high-reliability pressure sensor comprising the chip adopts a whole injection molding mode, the movable visibility of a bonding alloy wire is greatly reduced, meanwhile, the oxidation of the gold wire and other exposed parts by the external environment is isolated, and the whole reliability of the sensor is greatly improved. Before the integral injection molding, the shell is adopted to protect the chip part, so that the wire bonding place is prevented from being damaged in the injection molding process. The substrate and the chip are bonded by sintering, so that the chronic corrosion of compounds such as corrosive gas, liquid and the like to the bonding layer is avoided, the service life of the pressure sensor is greatly prolonged, and the testing precision is greatly improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic structural diagram of a chip according to an embodiment of the present invention;
FIG. 2 is a top view of a die of the present invention attached to a substrate in an embodiment;
FIG. 3 is a side view of a die of the present invention attached to a substrate in an embodiment;
FIG. 4 is a top view of a highly reliable pressure sensor of the present invention;
FIG. 5 is a cross-sectional view taken at A-A of FIG. 4;
in the figure: 10-chip, 1-silicon body, 2-glass, 3-vacuum cavity, 31-sensitive film, 32-front piezoresistor, 4-bonding pad, 5-substrate, 51-air inlet, 52-shell, 6-plastic piece and 7-leading-out terminal.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and it should be understood that the preferred embodiments described herein are merely for purposes of illustration and explanation, and are not intended to limit the present invention.
As shown in fig. 1 to 5, the highly reliable pressure sensor includes a chip 10, the chip 10 includes a silicon body 1 and a glass 2, the back of the glass 2 is bonded to the front of the silicon body 1, the back of the glass 2 is provided with a groove so that a vacuum chamber 3 is formed between the glass 2 and the silicon body 1, a sensitive film 31 and a front piezoresistor 32 are arranged in the vacuum chamber 3, the sensitive film 31 is attached to the front of the silicon body 1, thereby the whole body becomes a back pressure working mode, the measured medium can contact the silicon cup structure part on the back of the silicon body 1, and the silicon cup structure has good corrosion resistance, so the sensitive film 31 and the front piezoresistor 32 in the vacuum chamber 3 are not corroded and protected, and the sensitive film 31 attached to the front of the silicon body 1 can fully sense the pressure transmitted from the silicon cup structure 1, the vacuum chamber 3 also provides a sufficient active space for the sensitive film 31. The tested medium only contacts with the silicon material on the whole, so that the chip is ensured to be used under severe conditions or other occasions with corrosive gas and liquid, the problem of use under severe conditions is solved, and the requirement of high reliability is met.
The bonding PAD 4 is arranged on the front surface of the silicon body 1, and the bonding PAD 4 is positioned outside the glass 2, so that only the PAD part is exposed on the whole, and other parts are formed and protected by the corrosion-resistant structure, therefore, the silicon body has good corrosion resistance, and meets the requirement of high reliability.
The device also comprises a substrate 5, wherein the chip 10 is arranged on the substrate 5, the back of the substrate 5 is provided with an air inlet 51, and the air inlet 51 is opposite to the silicon cup structure on the back of the silicon body 1, so that a measured medium can pass through the air inlet 51 to contact with the silicon cup structure.
Meanwhile, the shell 52 is arranged on the substrate 5, and the upper surface of the substrate 5 and the chip 10 are wrapped by the shell 52, so that the chip 10 can be prevented from being damaged when the injection molding piece 6 is molded, and the routing place is protected. The plastic part 6 is plastically packaged outside the shell 52, and the air inlet 51 penetrates through the plastic part 6 to be communicated with the outside air, so that the chip 10, the bonding alloy wire, the substrate 5 and the like are protected by the shell 52, the isolation of the chip 10 from the peripheral environment is realized, and the circuit part of the pressure sensor is effectively prevented from contacting the severe environment.
The base 5 is also provided with an outgoing terminal 7, and the outgoing terminal 7 is in matched butt joint with an external circuit terminal, and the main function of the outgoing terminal is to transmit signals with external butt joint to detect pressure.
In this embodiment, the substrate 5 is made of ceramic, and the ceramic has good corrosion resistance and sealing performance, and also has a certain strength, so as to meet the requirement of use under severe environmental conditions.
In this embodiment, the substrate 5 and the highly reliable pressure sensor are fixedly connected by sintering adhesion, and the sintering medium may be metal paste or glass paste, so that the packaging form of the traditional glue is replaced by the sintering method.
In this embodiment, the plastic part 6 is molded on the housing 52 by integral injection molding, so that unstable phenomena of falling, radian reduction, vibration desoldering and the like of a bonding wire adopted in the traditional process due to use are avoided, the blank part of the device is completely filled by the integral injection molding, movable visibility of the bonding wire is greatly reduced, oxidation of an external environment to a gold wire and other exposed parts is isolated, and the integral reliability of the sensor is greatly improved. The whole outgoing electric signal leading-out terminal and other parts of the air inlet are protected by the plastic package, the whole firmness is high, and meanwhile, the whole structure is simple and smooth, and subsequent assembly is facilitated.
In summary, the structure design of the chip 10 of the highly reliable pressure sensor of the present invention firstly enables the tested medium to contact the silicon cup structure portion located at the back of the silicon body 1 through the working mode of back pressure test, and protects the sensitive film 31 and the front piezoresistor 32 in the vacuum chamber 3, the front surface of the silicon body 1 is provided with the bonding pad 4, the bonding pad 4 is located outside the glass 2, thus, only the PAD part is left exposed on the whole, the chip 10 is ensured to be used under severe environmental conditions or other occasions with corrosive gas and liquid, the requirement of high reliability is met, then, the high-reliability pressure sensor adopts the integral injection molding mode to greatly reduce the movable visibility of the key alloy wire, meanwhile, the oxidation of the gold wire and other exposed parts by the external environment is isolated, and the overall reliability of the sensor is greatly improved. Before the integral injection molding, the shell 52 is used to protect the chip 10 part, so as to prevent the wire bonding part from being damaged in the injection molding process. The substrate 5 and the chip are bonded by sintering, so that the chronic corrosion of compounds such as corrosive gas, liquid and the like to the bonding layer is avoided, and the service life and the test precision of the pressure sensor are greatly improved.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (4)
1. A highly reliable pressure sensor characterized by: the chip comprises a chip (10), wherein the chip (10) comprises a silicon body (1) with a back surface in a silicon cup structure and glass (2), the back surface of the glass (2) is bonded and arranged on the front surface of the silicon body (1), the back surface of the glass (2) is provided with a groove, so that a vacuum cavity (3) is formed between the glass (2) and the silicon body (1), a sensitive film (31) and a front surface piezoresistor (32) are arranged in the vacuum cavity (3), the sensitive film (31) is attached to the front surface of the silicon body (1), a bonding pad (4) is further arranged on the front surface of the silicon body (1), and the bonding pad (4) is positioned outside the glass (2);
the silicon chip is characterized by further comprising a substrate (5), the chip (10) is arranged on the substrate (5), an air inlet hole (51) is formed in the back of the substrate (5), and the air inlet hole (51) is opposite to the silicon cup structure on the back of the silicon body (1);
a shell (52) is arranged on the substrate (5), the upper surface of the substrate (5) and the chip (10) are wrapped by the shell (52), a plastic part (6) is plastically packaged outside the shell (52), and the air inlet (51) penetrates through the plastic part (6) to be communicated with the outside air;
the substrate (5) is further provided with an extraction terminal (7), and the extraction terminal (7) is in matched butt joint with an external circuit terminal.
2. A highly reliable pressure sensor as in claim 1, wherein: the substrate (5) is made of ceramic.
3. A highly reliable pressure sensor as in claim 1, wherein: the substrate (5) and the chip (10) are fixedly connected in a sintering adhesion mode.
4. A highly reliable pressure sensor as in claim 1, wherein: the plastic part (6) is injected on the shell (52) in an integral injection molding mode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911148984.7A CN110749394A (en) | 2019-11-21 | 2019-11-21 | High-reliability pressure sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911148984.7A CN110749394A (en) | 2019-11-21 | 2019-11-21 | High-reliability pressure sensor |
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| Publication Number | Publication Date |
|---|---|
| CN110749394A true CN110749394A (en) | 2020-02-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911148984.7A Pending CN110749394A (en) | 2019-11-21 | 2019-11-21 | High-reliability pressure sensor |
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| CN (1) | CN110749394A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020192661A1 (en) * | 2019-03-27 | 2020-10-01 | 西人马联合测控（泉州）科技有限公司 | Pressure sensor and packaging method thereof |
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2019
- 2019-11-21 CN CN201911148984.7A patent/CN110749394A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020192661A1 (en) * | 2019-03-27 | 2020-10-01 | 西人马联合测控（泉州）科技有限公司 | Pressure sensor and packaging method thereof |
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