CN112985653B - Pressure sensor's chip package unit and pressure sensor - Google Patents
Pressure sensor's chip package unit and pressure sensor Download PDFInfo
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- CN112985653B CN112985653B CN202110174993.4A CN202110174993A CN112985653B CN 112985653 B CN112985653 B CN 112985653B CN 202110174993 A CN202110174993 A CN 202110174993A CN 112985653 B CN112985653 B CN 112985653B
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- chip
- piezoresistive
- pressure sensor
- packaging unit
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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
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
- G01L1/2287—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges constructional details of the strain gauges
- G01L1/2293—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges constructional details of the strain gauges of the semi-conductor type
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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
- G01L9/04—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 resistance-strain gauges
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The application relates to a pressure sensor's chip package unit and pressure sensor, this pressure sensor's chip package unit include base member and pressure drag chip, and the pressure drag chip is fixed in via the installation of paster seat the base member, the pressure drag chip is pasted the dress with its bottom surface on the paster seat, under the mounted state, paster seat protrusion in the installation face of base member makes the pressure drag chip the bottom surface and base member it has the clearance to keep between the installation face. According to the design scheme provided by the invention, the stress isolation and the electrical isolation of the sensor chip can be effectively realized, so that the pressure sensor achieves better measurement performance, and the stability of the pressure sensor product is better improved.
Description
Technical Field
The invention relates to the technical field of sensing devices, in particular to a chip packaging unit of a pressure sensor and the pressure sensor.
Background
The pressure sensor is a device or apparatus capable of sensing a pressure signal and converting the pressure signal into an electrical signal for output. The pressure sensor is the most common sensor in industrial practice, is widely applied to various industrial automatic control environments, and relates to a plurality of industries such as water conservancy and hydropower, railway traffic, intelligent buildings, production automatic control, aerospace, military industry, petrochemical industry, oil wells, electric power, ships, machine tools, pipelines and the like.
At present, piezoresistive chips, especially silicon piezoresistive chips, are generally adopted as sensitive elements in the field of high-precision pressure sensor manufacturing.
On the one hand, however, the silicon pressure sensor is susceptible to internal stress transmitted in all directions of the packaging material during packaging, which causes signal offset of the sensor, and the internal stress represents long-term change, so that the pressure sensor has long-term drift influence.
On the other hand, the silicon material is a semiconductor material, and since the silicon substrate pressure chip is mostly directly packaged on the conductive metal material in the current technical link, the silicon material and the housing part form a leakage loop under a certain electrical environment, so that the silicon pressure sensor has poor anti-electromagnetic interference characteristics, the sensor measurement is influenced, and even permanent non-recoverable damage of the piezoresistive chip in the sensor can be caused.
It is therefore desirable to design a suitable low stress and electrically isolated pressure sensor die package.
Disclosure of Invention
In order to overcome the stress and leakage current influence caused by the direct packaging of the current pressure sensor chip on the metal base, the invention provides an improved sensor chip packaging structure.
Particularly, this application provides a pressure sensor's chip package unit, including base member and piezoresistive chip, the piezoresistive chip is fixed in via the installation of paster seat the base member, the piezoresistive chip with its bottom surface paste the dress on the paster seat, under the mounted state, paster seat protrusion in the installation face of base member makes the piezoresistive chip the bottom surface and base member keep the clearance between the installation face.
Therefore, a suspended pressure sensor packaging structure is formed, and the piezoresistive chip is not in direct mechanical contact and electrical contact with the substrate based on the arrangement of the patch seat.
Advantageously, the patch seat is made of an electrically insulating material.
The wafer holder is expediently of cylindrical design, the base body has a mounting opening, the cylindrical wafer holder is inserted into the mounting opening and projects with an end face from the mounting face of the base body.
Suitably, the internal diameter of base member mounting hole is greater than the external diameter of the cylindrical structure of paster seat, and the radial space between the two is filled with the sealing filler, and paster seat and base member can fix a position through the sealing filler who fills.
The inner diameter of the base mounting bore can expediently be 1.2 to 2.5 times the outer diameter of the cylindrical arrangement of the wafer holder.
Advantageously, the sealing filler may be swellable polymer particles.
According to one embodiment of the invention, the piezoresistive chip is attached to the end face of the die pad by means of an encapsulation adhesive on at least a partial region of the bottom surface of the piezoresistive chip.
Furthermore, the area of the end surface of the cylindrical structure of the patch base is smaller than the area of the bottom surface of the piezoresistive chip, and the piezoresistive chip is attached to the end surface of the patch base in the central area of the bottom surface of the piezoresistive chip.
According to one embodiment of the invention, the gap may be 0.2 to 2 times the thickness of the piezoresistive die.
Suitably, the piezoresistive chip is a silicon piezoresistive chip.
For this purpose, the wafer seat is expediently made of a ceramic material whose coefficient of thermal expansion differs from that of the silicon material by no more than 10%. Thereby substantially avoiding thermal stresses that may be caused by bonding the die pad to the silicon piezoresistive die.
In another aspect, the present application further provides a pressure sensor, including: the sensor comprises a sensor base and the chip packaging unit, wherein the base body of the chip packaging unit is fixedly connected with the sensor base or integrally formed with the sensor base.
According to the invention, a 'suspension' packaging structure is adopted for the sensor chip. Therefore, the stress isolation and the electrical isolation of the sensor chip (such as a silicon piezoresistive chip) can be effectively realized, the electrical performance of the sensor chip is improved, and the stress generated during packaging of the sensor chip is reduced, so that the pressure sensor achieves better measurement performance, and the stability of the pressure sensor product is better improved.
Drawings
An exemplary embodiment of the invention is shown in the drawings. The embodiments and figures disclosed herein are to be regarded as illustrative rather than restrictive. It is also noted that for purposes of clarity of illustration, certain features are not necessarily drawn to scale in the drawings.
Fig. 1 is a schematic structural diagram of a chip packaging unit of the pressure sensor of the present invention.
Detailed Description
The following description is provided to illustrate the technical solutions of the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art. The principles of the invention, as defined in the following description, may be applied to other embodiments, variations, modifications, equivalents, and other technical solutions without departing from the spirit and scope of the invention. Also, it is noted that a feature, structure, or characteristic described herein in connection with one embodiment is not necessarily limited to the particular embodiment, nor is it intended to be mutually exclusive of other embodiments, as those skilled in the art will recognize various combinations of features of different embodiments as may be contemplated within the scope of the appended claims.
In the specification, the terms "including"/"comprising" and "having," and any variant thereof, are intended to cover non-exclusive inclusions. For example, a process, method, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus. In the description of the present application, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are merely for convenience in describing the present invention and simplifying the description, and do not mean that the corresponding device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus the above terms should not be construed as limiting the present invention. In addition, the terms "a" and "an" should be interpreted as "at least one" or "one or more," i.e., the number of an element can be one in one embodiment and the number of the element can be plural in another embodiment, i.e., the terms "a" and "an" should not be interpreted as limiting the number.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art and may be specifically interpreted based on their context within the context of the description of the relevant art.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
On the one hand, this application provides a pressure sensor's chip package unit, as shown in fig. 1, it includes base member 1 and piezoresistive chip 4, the piezoresistive chip is fixed in via the installation of sticker seat 5 the base member, piezoresistive chip 4 with its bottom surface subsides dress in on the sticker seat 5, under the mounted state, sticker seat 5 protrusion in the installation face of base member 1 makes piezoresistive chip 4 the bottom surface and base member 1 the installation face between keep the clearance.
Advantageously, the wafer holder 5 is made of an electrically insulating material.
Further, the patch holder 5 has a cylindrical structure, the base 1 has a mounting hole, and the cylindrical patch holder is inserted into the mounting hole and protrudes from the mounting surface of the base 1 with one end surface.
Further, the internal diameter of base member mounting hole is greater than the external diameter of the cylindrical structure of paster seat, and the radial space between the two is filled with sealing filler 2, and paster seat 5 and base member 1 can fix a position through the sealing filler 2 who fills.
For this purpose, the inner diameter of the base mounting bore is preferably 1.2 to 2.5 times the outer diameter of the cylindrical structure of the patch holder.
Advantageously, the sealing filler is a swelling polymer particle. In this way, during assembly, the granular filler can be easily filled into the radial gap between the base body and the patch holder, and the volume of the granular filler is expanded by adding a corresponding solvent, so that the base body and the patch holder can be firmly and hermetically bonded together after the material is cured. Of course, it is also contemplated that other suitable high strength seal fillers may be used, and the bond strength generated by the seal filler is preferably 1.2 times or more the maximum allowable value of the pressure sensor, for example, a level of more than 50MPa may be achieved depending on the actual application.
According to one embodiment of the present invention, the piezoresistive chip 4 is attached to the end surface of the die pad by a packaging adhesive 3 at least in a partial region of the bottom surface of the piezoresistive chip.
Suitably, as shown in figure 1, the area of the end face of the cylindrical structure of the patch holder is smaller than the area of the bottom face of the piezoresistive chip 4, which is attached to the end face of the patch holder in the central region of its bottom face.
According to one embodiment of the invention, the gap may be 0.2 to 2 times the thickness of the piezoresistive chip 4.
The piezoresistive chip 4 may be a silicon piezoresistive chip.
For this purpose, the wafer holder 5 is expediently made of a ceramic material whose coefficient of thermal expansion differs from that of the silicon material by no more than 10%.
In another aspect, the present application further provides a pressure sensor, including: the sensor comprises a sensor base and the chip packaging unit, wherein the base body 1 of the chip packaging unit is fixedly connected with the sensor base or integrally formed with the sensor base.
As described above, for the pressure sensor of the present application, the pressure sensor chip may be configured as a silicon pressure sensor chip, particularly a silicon piezoresistive pressure sensor chip based on the wheatstone bridge principle, such as two piezoresistive chips of diffused silicon and single crystal silicon. When pressure is applied to the pressure sensing surface of the chip, the resistance formed by the PN junction arranged on the pressure sensing surface becomes large and small in pairs, and differential mode output voltage is formed, namely the output signal of the sensor, and the signal is proportional to the excitation voltage and the excitation pressure.
Based on the pressure measuring principle of the pressure sensor, the pressure sensor designed by the invention can be widely applied to the field of industrial automation control for measuring pressure, differential pressure and flow, and is an important component of a pressure transmitter, a differential pressure transmitter and a flow transmitter, wherein the flow measurement can be obtained by converting the differential pressure measurement.
According to the invention, a "floating" package is used, in particular for the sensor chip. Therefore, the stress isolation and the electrical isolation of the sensor chip (such as a silicon piezoresistive chip) can be effectively realized, the electrical performance of the sensor chip is improved, and the stress generated during packaging of the sensor chip is reduced, so that the pressure sensor achieves better measurement performance, and the stability of the pressure sensor product is better improved.
Examples
Fig. 1 shows a chip package unit of a pressure sensor, which includes a base 1, a die pad 5, and a piezoresistive chip 4, wherein a sealing filler 2 is filled between the die pad 5 and the base 1, and the sealing filler 2 generates a force between the die pad 5 and the base 1, the force being radial with respect to the die pad 5, and the stress does not have an additional influence on the die pad 5 of the sensor. Thus, on the one hand, the filling of the sealing filler 2 ensures the relative stability of the patch seat 5 and the substrate 1, and on the other hand, the sealing filler 2 has the functions of sealing and isolating the inside and electrical interference.
The patch seat 5 is arranged to be a cylindrical structure, the structure of the patch seat is that a supporting plane is slightly higher than the base body 1, the material of the patch seat can be alumina ceramic, the thermal expansion coefficient of the alumina ceramic is close to that of silicon, and the patch seat is manufactured by adopting a preparation process which improves the electrical characteristic and avoids electric leakage.
The piezoresistive chip 4 and the patch base 5 can be fixed by packaging glue 3.
The piezoresistive chip 4 is typically a silicon pressure sensor chip, and can be applied to a pressure sensor for measuring pressure, and pressure to be measured is generally transmitted to the piezoresistive chip 4 of the pressure sensor through a diaphragm and a pressure-conducting medium, i.e., the pressure to be measured is transmitted from the P1 side of fig. 1, for example, and the piezoresistive chip converts a pressure signal into an electrical signal and transmits the electrical signal continuously, or is indicated by a pointer on an instrument panel. The side P2 shown in fig. 1 may be connected to the atmosphere, an absolute pressure chamber, a pressure chamber.
When the piezoresistive chip is used as a differential mode pressure sensing chip, the corresponding pressure sensor can be configured as a differential pressure sensor for measuring differential pressure. Generally, the pressure to be measured is transmitted to the piezoresistive chip of the pressure sensor through the diaphragm and the pressure-guiding medium, that is, for example, one pressure to be measured is transmitted from the P1 side of fig. 1, and the other pressure to be measured is transmitted from the P2 side of fig. 1, and then the pressure/differential pressure signal is sensed by the pressure sensor and is converted into an electrical signal after being calculated.
According to the preferred embodiment of the invention, the high-strength sealing filler is radially filled between the substrate and the patch base, so that the pressure on the P1 side (which can be set as a high-pressure side) and the P2 side (which can be set as a low-pressure side) is isolated, and the filling stress is perpendicular to the packaging direction of the pressure chip due to the radial filling, and no additional stress influence is generated on the pressure chip; the patch seat is of a cylindrical structure, and adopts a ceramic material with a coefficient of thermal expansion close to that of silicon, so that the packaging stress and the thermal stress generated by combining the patch seat with packaging glue and a piezoresistive chip are greatly reduced, and the electrical characteristics of the ceramic material are greatly improved by adopting a specific preparation process, so that the influence of electric leakage is avoided; the ceramic materials described therein may include alumina, aluminum nitride, silicon nitride, and the like.
The pressure sensor adopting the suspension type pressure sensor packaging structure has the advantages that the long-term drift influence of the pressure sensor adopting the suspension type pressure sensor packaging structure is greatly reduced, the leakage current of a silicon chip is reduced, and the long-term stability and the anti-interference capability of the sensor are improved.
The above description is only a preferred embodiment of the present application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.
Claims (10)
1. A chip packaging unit of a pressure sensor comprises a base body (1) and a piezoresistive chip (4),
the piezoresistive chip is characterized in that the piezoresistive chip is mounted and fixed on the base body through a patch seat (5), the bottom surface of the piezoresistive chip (4) is mounted on the patch seat (5), and in the mounting state, the patch seat (5) protrudes out of the mounting surface of the base body (1) so that a gap is reserved between the bottom surface of the piezoresistive chip (4) and the mounting surface of the base body (1);
the patch base (5) is of a cylindrical structure, the base body (1) is provided with a mounting hole, and the cylindrical patch base is inserted into the mounting hole and protrudes out of a mounting surface of the base body (1) by one end surface;
the internal diameter of base member mounting hole is greater than the external diameter of the cylindrical structure of paster seat, and it has packing (2) to fill in the radial space between the two, and paster seat (5) and base member (1) can fix a position fixedly through packing (2) that fill.
2. Chip packaging unit according to claim 1, characterized in that the die pad (5) is made of an electrically insulating material.
3. The chip packaging unit of claim 1, wherein the inner diameter of the substrate mounting hole is 1.2 to 2.5 times the outer diameter of the cylindrical structure of the die pad.
4. The chip packaging unit of claim 1, wherein the encapsulant is swellable polymer particles.
5. The chip packaging unit according to claim 1, wherein the piezoresistive chip (4) is attached to the end face of the die pad by a packaging adhesive (3) at least in a partial region of its bottom surface.
6. The chip packaging unit according to claim 5, characterized in that the area of the end face of the cylindrical structure of the die pad is smaller than the area of the bottom face of the piezoresistive chip (4), which is attached to the end face of the die pad in the central region of its bottom face.
7. The chip packaging unit according to any one of claims 1 to 6, characterized in that the gap is 0.2 to 2 times the thickness of the piezoresistive chip (4).
8. The chip packaging unit according to any one of claims 1 to 6, characterized in that the piezoresistive chip (4) is a silicon piezoresistive chip.
9. The chip packaging unit according to claim 8, wherein the die pad (5) is made of a ceramic material having a coefficient of thermal expansion that differs by no more than 10% from the coefficient of thermal expansion of the silicon material.
10. A pressure sensor, characterized in that it comprises:
a sensor base, and
the chip packaging unit according to any one of claims 1 to 9, wherein the base body of the chip packaging unit is fixedly connected with the sensor base or is integrally formed with the sensor base.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202110174993.4A CN112985653B (en) | 2021-02-09 | 2021-02-09 | Pressure sensor's chip package unit and pressure sensor |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110174993.4A CN112985653B (en) | 2021-02-09 | 2021-02-09 | Pressure sensor's chip package unit and pressure sensor |
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| CN112985653A CN112985653A (en) | 2021-06-18 |
| CN112985653B true CN112985653B (en) | 2022-04-12 |
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| CN116625559B (en) * | 2023-07-24 | 2023-10-13 | 昆山灵科传感技术有限公司 | Pressure sensor and pressure composite sensor |
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| JP3307268B2 (en) * | 1997-04-18 | 2002-07-24 | 松下電工株式会社 | Semiconductor pressure sensor |
| CN106134489B (en) * | 2012-12-26 | 2014-10-22 | 北京遥测技术研究所 | A kind of high-temp pressure sensor encapsulating structure |
| CN104132768B (en) * | 2014-07-01 | 2017-03-29 | 苏州大学 | A kind of pressure sensor of the insulation package stress based on Si-Si bonding |
| CN208399071U (en) * | 2018-07-27 | 2019-01-18 | 扬州扬杰电子科技股份有限公司 | Silicon piezoresistance type pressure sensor packaging structure |
| CN111128921A (en) * | 2020-01-08 | 2020-05-08 | 上海立格仪表有限公司 | Sensor packaging structure |
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