CN116839766A - High-precision silicon piezoresistive pressure sensor chip - Google Patents

High-precision silicon piezoresistive pressure sensor chip Download PDF

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Publication number
CN116839766A
CN116839766A CN202310679952.XA CN202310679952A CN116839766A CN 116839766 A CN116839766 A CN 116839766A CN 202310679952 A CN202310679952 A CN 202310679952A CN 116839766 A CN116839766 A CN 116839766A
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China
Prior art keywords
chip
silicon piezoresistive
pressure sensor
pressure sensitive
piezoresistive pressure
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Pending
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CN202310679952.XA
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Chinese (zh)
Inventor
王淞立
赵虎
申建武
徐林鹏
董奎
刘泽庆
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Xi'an Siwei Sensor Technology Co ltd
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Xi'an Siwei Sensor Technology Co ltd
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Application filed by Xi'an Siwei Sensor Technology Co ltd filed Critical Xi'an Siwei Sensor Technology Co ltd
Priority to CN202310679952.XA priority Critical patent/CN116839766A/en
Publication of CN116839766A publication Critical patent/CN116839766A/en
Pending legal-status Critical Current

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01LMEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00Measuring force or stress, in general
    • G01L1/18Measuring 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
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01LMEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00Measuring force or stress, in general
    • G01L1/20Measuring 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

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

The application provides a high-precision silicon piezoresistive pressure sensor chip, which comprises a substrate layer, wherein the upper end of the substrate layer is provided with a pressure sensitive layer, the pressure sensitive layer is provided with a pressure sensitive film, the pressure sensitive film is provided with a piezoresistor, the pressure sensitive layer is provided with a chip electrode corresponding to the piezoresistor, the chip electrode is used for intermediating the connection of the piezoresistor and an external lead, and the substrate layer is provided with a chip bonding area. The chip is designed in such a way that the bonding area is far away from the stress sensitive area as much as possible, so that the physical characteristic change of the adhesive is transmitted to the silicon piezoresistive pressure chip as little as possible, and the long-term stability of the silicon piezoresistive pressure sensor is improved.

Description

High-precision silicon piezoresistive pressure sensor chip
Technical Field
The application relates to the technical field of mechanical sensors, in particular to a high-precision silicon piezoresistive pressure sensor chip.
Background
The silicon piezoresistive pressure chip needs to be packaged when in use, and the silicon piezoresistive pressure chip is connected with the packaging shell in a manner of adhesive, as shown in fig. 1 a. Fig. 1a is a typical silicon piezoresistive pressure chip TO8 package, mainly comprising a base, a pressure chip, a cap and an adhesive, wherein the base is made of kovar alloy material for reducing the influence of a temperature sensor, because the kovar alloy has a higher matching degree with the thermal expansion coefficient of silicon.
The silicon piezoresistive pressure chip and the base are fixed in an adhesive mode, silicon rubber is generally used for adhesive bonding, and creep and aging effects naturally exist in the long-term use process of the silicon rubber, so that the external stress environment of the silicon piezoresistive pressure chip can be changed slowly, the silicon piezoresistive pressure chip belongs to a stress sensitive device, and creep and hysteresis of the adhesive are accumulated for a long time, so that slow drift of output of the pressure chip can be caused. In order to solve the problem of slow drift of the silicon piezoresistive pressure sensor in the current industry, some measures and measures are adopted:
1. the thickness of the silicon piezoresistive pressure chip glass substrate is increased. As shown in FIG. 1b, a silicon piezoresistive pressure chip is generally composed of a two-layer structure, with the upper layer being silicon and the lower layer being glass. In order to isolate the stress of the adhesive tape, a manufacturer thickens the glass and reduces the transmission of the stress from the bottom to the surface of the chip as much as possible, and the mode can reduce the influence of the stress on the performance of the chip to a certain extent, but the thickness of the glass cannot be too thick due to the limitation of the structural size of the sensor, otherwise, many application scenes cannot be used due to the limitation of the volume;
2. a low stress adhesive is used. In this respect, researches are always carried out at home and abroad, and various adhesives are tried, but as most of materials of the adhesives are based on silicon rubber, the hysteresis and creep effects of the silicon rubber naturally exist, so that the problem of long-term drifting of the silicon piezoresistive pressure chip is not fundamentally solved;
3. and (5) performing accelerated aging on the packaged pressure sensor. The research institutions at home and abroad accelerate the hysteresis and creep processes of the rubber by performing multiple physical field actions such as temperature circulation, pressure circulation, vibration and the like on the pressure sensor, and expect to reduce the slow drift of the silicon piezoresistive pressure sensor, so that the method can play a certain role, is considered as a more effective method by the industry, but does not fundamentally solve the slow drift problem of the silicon piezoresistive pressure sensor;
the means and measures can only improve the output slow drift of the silicon piezoresistive pressure sensor, and can not fundamentally solve the problems.
The phenomenon that the output of the silicon piezoresistive pressure sensor slowly drifts along with time is generally caused by slow creep and hysteresis of adhesive glue, and the current industry mainly adopts methods of increasing the thickness of a glass substrate of the silicon piezoresistive pressure sensor, adopting low-stress adhesive, carrying out accelerated aging and stress release on the pressure sensor and the like to relieve the problem of the slow drift along with time of the output of the sensor, and the methods only can improve the problem of the slow drift of the silicon piezoresistive pressure sensor and cannot fundamentally solve the problem.
Disclosure of Invention
The present application has been made to solve the technical problems occurring in the prior art. Therefore, a high-precision silicon piezoresistive pressure sensor chip is needed, the pressure sensor chip is provided with a region special for bonding the chip, and the region is far away from a pressure sensitive region, so that the problems of hysteresis and creep caused by adhesive can be solved, and the problem of slow drift of the output of the silicon piezoresistive pressure sensor is thoroughly solved fundamentally.
In order to solve the problems, the application provides a high-precision silicon piezoresistive pressure sensor chip, which adopts the following technical scheme:
the high-precision silicon piezoresistive pressure sensor chip comprises a substrate layer, wherein the upper end of the substrate layer is provided with a pressure sensitive layer, the pressure sensitive layer is provided with a pressure sensitive film, the pressure sensitive film is provided with a piezoresistor, the pressure sensitive layer is provided with a chip electrode corresponding to the piezoresistor, the chip electrode is used for intermediating the connection of the piezoresistor and an external lead, and the substrate layer is provided with a chip bonding area.
As a preferable technical scheme, the substrate layer is a glass substrate layer or a silicon substrate layer.
As a preferable technical scheme, the chip electrode is an aluminum electrode, and can also be a gold electrode or other composite metal electrodes.
As a preferable technical scheme, the pressure sensitive film is disposed on the left side of the pressure sensitive layer, and the die bonding area is disposed on the right side of the base layer.
As an optimal technical scheme, the high-precision silicon piezoresistive pressure sensor chip adopts a pneumatic TO8 package or an oil-filled isolation type package.
The beneficial effects of the application are as follows: the application provides a high-precision silicon piezoresistive pressure sensor chip, and the chip is designed in a way that an adhesion area is kept away from a stress sensitive area as far as possible, so that the physical characteristic change of glue is transferred to the silicon piezoresistive pressure chip as little as possible, and the long-term stability of the silicon piezoresistive pressure sensor is improved.
Drawings
FIG. 1a shows a schematic diagram of a typical TO8 package for a silicon piezoresistive pressure die according TO the prior art.
Figure 1b shows a block diagram of a silicon piezoresistive pressure die according to the prior art.
FIG. 2 illustrates a perspective view of a high precision silicon piezoresistive pressure sensor die according to an embodiment of the present application.
FIG. 3 (a) shows a schematic diagram of a pneumatic TO8 package for a high accuracy silicon piezoresistive pressure sensor die according TO embodiments of the application.
FIG. 3 (b) shows a schematic diagram of an oil filled isolation type package for a high precision silicon piezoresistive pressure sensor die according to an embodiment of the present application.
In the figure, 1 is a basal layer, 2 is a pressure sensitive layer, 3 is a pressure sensitive film, 4 is a piezoresistor, 5 is a chip electrode, and 6 is a chip bonding area.
Detailed Description
Other advantages and effects of the present application will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present application with reference to specific examples. The application may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present application. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.
In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front," "rear," "head," "tail," and the like are used as an orientation or positional relationship based on that shown in the drawings, merely to facilitate description of the application and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the application. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
The following describes in further detail the embodiments of the present application with reference to the drawings and examples.
The embodiment of the application provides a high-precision silicon piezoresistive pressure sensor chip. As shown in fig. 2, the high-precision silicon piezoresistive pressure sensor chip comprises a substrate layer 1, wherein a pressure sensitive layer 2 is arranged at the upper end of the substrate layer 1, a pressure sensitive film 3 is arranged on the pressure sensitive layer 2, a piezoresistor 4 is arranged on the pressure sensitive film 3, a chip electrode 5 is arranged on the pressure sensitive layer 2 corresponding to the piezoresistor 4, the chip electrode 5 is used for the intermediary of connecting the piezoresistor 4 with an external lead, and a chip bonding area 6 is arranged on the substrate layer 1.
According to the embodiment, the high-precision silicon piezoresistive pressure sensor chip provided in fig. 2 is generally represented by two layers, namely, a substrate layer 1 and a pressure sensitive layer 2, the substrate layer 1 is preferably a glass substrate layer, the pressure sensitive layer 2 is preferably made of silicon, a pressure sensitive film 3 with a certain thickness is manufactured on the pressure sensitive layer 2 according to different measuring ranges of the pressure chip, when external pressure acts on the pressure sensitive film 3, the pressure sensitive film 3 is bent to generate stress, so that a piezoresistor 4 is arranged on the pressure sensitive film to change, a pressure value can be obtained by measuring the change of resistance, the number of the piezoresistor 4 and the chip electrode 5 is determined according to practical situations, and the number of the piezoresistor 4 and the chip electrode 5 can be set to be 1 or more.
The chip electrode 5 is generally made of aluminum material, and the chip electrode is used as an intermediary for connecting the piezoresistor with an external wire, and the quality of ohmic contact resistance between the chip electrode and the silicon material can influence the performance of the whole chip.
The die attach area 6 is the area where bonding of the die to the package can is achieved, and as can be seen in fig. 2, the die attach area 6 is further from the pressure sensitive membrane, so that bond induced hysteresis and creep stresses are effectively isolated.
In practical applications, the two most common packaging forms of silicon piezoresistive pressure chips are pneumatic TO8 packaging, as shown in FIG. 3 (a), and oil-filled isolation packaging, as shown in FIG. 3 (b).
The area I circled in fig. 3 (a) is the glue area, and as can be seen from the TO8 package, the glue area is far away from the pressure sensitive film, and creep and hysteresis of the glue are well isolated; the area I circled in fig. 3 (b) is an adhesive area, which is far away from the chip pressure sensitive film, and can also play a role in isolating adhesive stress.
In summary, the high-precision silicon piezoresistive pressure sensor chip provided by the embodiment of the application is a high-precision pressure sensor chip structure capable of isolating adhesive stress, and has at least the following advantages:
1. a silicon piezoresistive pressure chip capable of isolating adhesive stress is designed;
2. the problem of long-term slow drift of the output of the silicon piezoresistive pressure sensor is solved;
3. the silicon piezoresistive pressure sensor chip can adapt TO a common pneumatic TO8 packaging structure and also can adapt TO a common oil-filled isolation type packaging structure;
4. the design concept can be popularized to other sensor chip structures needing to isolate adhesive stress.
The above embodiments are only for illustrating the present application, not for limiting the present application, and various changes and modifications may be made by one of ordinary skill in the relevant art without departing from the spirit and scope of the present application, and therefore, all equivalent technical solutions are also within the scope of the present application, and the scope of the present application is defined by the claims.

Claims (5)

1. The high-precision silicon piezoresistive pressure sensor chip is characterized by comprising a substrate layer, wherein the upper end of the substrate layer is provided with a pressure sensitive layer, the pressure sensitive layer is provided with a pressure sensitive film, the pressure sensitive film is provided with a piezoresistor, the pressure sensitive layer is provided with a chip electrode corresponding to the piezoresistor, the chip electrode is used for intermediating the connection of the piezoresistor and an external lead, and the substrate layer is provided with a chip bonding area.
2. The high precision silicon piezoresistive pressure sensor die according to claim 1, wherein the substrate layer is a glass substrate layer.
3. The high precision silicon piezoresistive pressure sensor die according to claim 1, wherein the die electrode is an aluminum electrode or other material electrode.
4. The high precision silicon piezoresistive pressure sensor die of claim 1, wherein the pressure sensitive membrane is disposed on top of one side of the pressure die and the die attach area is disposed on the bottom of the other side of the pressure die.
5. The high precision silicon piezoresistive pressure sensor die according TO any of claims 1 TO 4, characterized in that the high precision silicon piezoresistive pressure sensor die employs a pneumatic TO8 package or an oil filled isolation type package.
CN202310679952.XA 2023-06-08 2023-06-08 High-precision silicon piezoresistive pressure sensor chip Pending CN116839766A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310679952.XA CN116839766A (en) 2023-06-08 2023-06-08 High-precision silicon piezoresistive pressure sensor chip

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310679952.XA CN116839766A (en) 2023-06-08 2023-06-08 High-precision silicon piezoresistive pressure sensor chip

Publications (1)

Publication Number Publication Date
CN116839766A true CN116839766A (en) 2023-10-03

Family

ID=88159097

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310679952.XA Pending CN116839766A (en) 2023-06-08 2023-06-08 High-precision silicon piezoresistive pressure sensor chip

Country Status (1)

Country Link
CN (1) CN116839766A (en)

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