CN217654652U

CN217654652U - Capacitive pressure sensitive chip

Info

Publication number: CN217654652U
Application number: CN202220348834.1U
Authority: CN
Inventors: 姜贵民; 杨宇新; 杨超
Original assignee: Wuxin Liaoning High Tech Co ltd
Current assignee: Wuxin Liaoning High Tech Co ltd
Priority date: 2022-02-21
Filing date: 2022-02-21
Publication date: 2022-10-25
Anticipated expiration: 2032-02-21

Abstract

A capacitive pressure sensitive chip belongs to the technical field of Micro Electro Mechanical Systems (MEMS), and particularly relates to a capacitive pressure sensitive chip. The invention provides a capacitive pressure sensitive chip with excellent performance. The invention comprises a substrate, and is characterized in that a pressure-sensing lower polar plate is arranged on the substrate, a pressure-sensing upper polar plate is arranged above the lower polar plate, and a cavity is arranged between the upper polar plate and the lower polar plate.

Description

Capacitive pressure sensitive chip

Technical Field

The utility model belongs to the technical field of micro-electro-mechanical system (MEMS), especially, relate to a capacitanc pressure sensitive chip.

Background

With the development of the MEMS technology, the pressure sensor becomes an indispensable key device in various industries, and has been widely applied in the fields of automotive electronics, petrochemical industry, biomedicine, national defense, military industry, and the like. Compared with a piezoresistive pressure sensor, the capacitive pressure sensor has the advantages of high sensitivity, low power consumption, good temperature characteristic and the like, and is more suitable for developing a high-precision pressure sensor. Particularly, under the background that the requirements on the pressure measurement precision and the reliability are increasingly increased in the aspects of modern aerospace technology, modern national defense equipment and the like, the research of the MEMS capacitive pressure sensor is highly emphasized at home and abroad.

For a common capacitive pressure sensor, a parallel plate capacitor structure is generally adopted, the parallel plate capacitor structure mainly comprises a movable polar plate and a fixed polar plate, when pressure acts on the movable polar plate, the distance between the two polar plates is changed, so that a capacitance value is changed, the pressure is measured by detecting the capacitance value, but the defects of serious nonlinearity between input and output, low overload capacity and the like exist.

In addition, a contact capacitance type pressure sensitive structure is provided, which is mainly characterized in that a pressure sensing upper polar plate can contact a dielectric layer on a lower polar plate along with the continuous increase of the external pressure in the working process, and at the moment, an output capacitance value and the pressure change present an approximate linear relation, so that the linearity of the common capacitance type pressure sensor is improved to a certain extent, but the sensitivity is relatively low, and the linearity and the linear response range are required to be further improved.

SUMMERY OF THE UTILITY MODEL

The utility model discloses to above-mentioned problem, provide a capacitanc pressure sensitive chip of excellent performance.

In order to achieve the purpose, the utility model adopts the following technical scheme, the utility model discloses a basement, its characterized in that is provided with pressure sensing bottom plate on the basement, and the bottom plate top is provided with pressure sensing upper polar plate, is provided with the cavity between upper polar plate and the bottom plate.

As a preferable scheme, the substrate of the invention adopts monocrystalline silicon or polycrystalline silicon or glass or ceramic substrate.

As another preferred scheme, the substrate of the utility model adopts glass.

As another preferred scheme, the utility model discloses set up into pressure passageway or into pressure cavity on the basement.

As another preferred scheme, the pressure sensing lower polar plate of the utility model is provided with a dielectric layer.

As another preferred scheme, the cavity of the utility model is a sealed cavity.

As another preferred scheme, the utility model discloses upper polar plate and bottom plate pass through pressure welding point and metal lead wire or pressure welding point and external circuit connection.

As another preferred scheme, the lower extreme of basement be provided with the cushion.

As another preferred scheme, the basement is the cyclic annular basement that the middle part was opened.

Secondly, be provided with the draw-in groove that can make the unsettled setting of chip make bottom plate pressure sensing on the basement that the middle part was opened.

Additionally, the draw-in groove sets up periphery lower extreme or the peripheral middle part at the basement.

The utility model has the advantages of.

The utility model provides a double acting polar plate capacitanc pressure sensitive structure, upper and lower bipolarplate all can the pressure sensing movable. When external pressure exists, the upper polar plate and the lower polar plate can deform under the action of the pressure at the same time to form a double-acting effect, and capacitance values between the two polar plates change to convert pressure signals into electric signals to be output; with the continuous increase of the pressure, the upper polar plate and the lower polar plate are contacted with each other, the contact area is changed at a nearly constant increasing rate, and the rate is faster than that of the common contact capacitance type pressure sensitive structure. Therefore, the pressure sensitive chip shows higher sensitivity and more excellent output characteristic, improves the performance of the sensor and is particularly suitable for developing a micro-range pressure sensor.

Drawings

The present invention will be further described with reference to the accompanying drawings and the following detailed description. The scope of protection of the present invention is not limited to the following description.

Fig. 1 is a schematic diagram of the structure of the present invention using an annular base and a cushion block.

Fig. 2 is a schematic view of the structure of the clamping groove arranged on the base of the present invention.

In the figure, 1 is a substrate, 2 is a dielectric layer, 3 is a lower polar plate, 4 is an upper polar plate, 5 is a dielectric layer, 8 is a cushion block, 9 is a cavity, 10 is a clamping groove, and 11 is a pressure inlet cavity.

Detailed Description

As shown in the figure, the utility model discloses a basement 1 is provided with pressure sensing bottom plate 3 on the basement 1, and bottom plate 3 top is provided with pressure sensing top plate 4, is provided with cavity 9 between top plate 4 and the bottom plate 3.

The lower polar plate 3 and the upper polar plate 4 which are arranged on the substrate 1 are both pressure-sensitive movable structures, when external pressure exists, the upper polar plate 4 and the lower polar plate 3 can be simultaneously deformed under the action of pressure to form a double-acting effect, so that the capacitance value between the two polar plates is changed, and a pressure signal is converted into an electric signal to be output.

The substrate 1 may be a monocrystalline silicon substrate, may also be glass, and may also be other materials.

And a dielectric layer 5 is arranged on the pressure sensing lower polar plate 3. When external pressure exists, the upper polar plate and the lower polar plate can deform under the action of the pressure at the same time to form a double-acting effect; with the increasing of the pressure, the upper polar plate 4 and the medium layer 5 on the lower polar plate 3 are contacted with each other.

The cavity 9 is a sealed cavity.

The upper polar plate 4 and the lower polar plate 3 are connected with an external circuit through a pressure welding point and a metal lead wire or a pressure welding point. The upper polar plate 4 and the lower polar plate 3 can be connected with an external circuit through a pressure welding point and a metal lead wire or a pressure welding point to form a pressure detection circuit, and pressure signals are converted into electric signals to be output.

And a pressure inlet chamber 11 is arranged below the pressure sensing lower polar plate 3.

As shown in fig. 1, the lower end of the substrate 1 is provided with a spacer 8. The cushion blocks 8 lift the substrate 1 by a certain height, so that a gap is reserved between the lower end face of the substrate 1 and the upper end face of the circuit board, the cushion blocks 8 are not annular bodies, the cushion blocks 8 can be arranged along the circumferential direction, and pressure inlet channels are formed between the adjacent cushion blocks 8.

As shown in fig. 2, a clamping groove 10 for suspending the chip to enable the lower plate 3 to sense pressure is disposed on the annular substrate 1 opened in the middle.

The clamping groove 10 is arranged at the lower end of the periphery of the substrate 1.

The upper and lower pressure sensing polar plates of the utility model can be designed into any expected shape, such as square, rectangle, circle, ring, etc.

The dielectric layer 2 is arranged on the lower polar plate 3, the dielectric layer 2 is arranged on the upper polar plate 4, and the silicon dioxide 2 plays an insulating protection role.

As shown in the figure, the upper and lower polar plates of the utility model are both pressure-sensitive movable structures, the lower polar plate 3 can be arranged on the substrate 1, and the lower polar plate 3 is suspended and movable relative to the substrate 1; the upper and lower polar plates sense pressure simultaneously, the upper and lower polar plates 3 are connected with an external circuit through pressure welding points and metal leads, and pressure signals are converted into electric signals to be output.

When external pressure exists, the upper polar plate and the lower polar plate are simultaneously under the action of pressure, the pressure sensing deformation of the two polar plates is bent, the distance between the polar plates is changed, and therefore the capacitance value is changed; when the pressure is higher than a certain pressure value, namely the contact pressure, the upper electrode plate 4 and the dielectric layer 5 on the lower electrode plate 3 are mutually contacted, the contact area is increased at an approximately constant increasing rate in the process, so that the contact capacitance value is very fast far larger than the non-contact capacitance value, and the measurement capacitance is mainly contact capacitance. Therefore, in the pressure range, the sensor shows more excellent linearity and higher output capacitance value, and the performance of the sensor is improved.

The upper and lower pressure sensing polar plates can adopt diaphragms with any shapes.

The utility model provides a double acting polar plate capacitanc pressure sensitive chip can be used to consumer electronics, petrochemical, automotive electronics, medical treatment, aerospace and national defense war industry etc. a plurality of fields medium pressure measurement.

It should be understood that the above detailed description of the present invention is only for illustrating the present invention and is not limited by the technical solutions described in the embodiments of the present invention, and those skilled in the art should understand that the present invention can still be modified or equivalently replaced to achieve the same technical effects; as long as the use requirement is satisfied, the utility model is within the protection scope.

Claims

1. The capacitive pressure sensitive chip comprises a substrate and is characterized in that a pressure sensing lower polar plate is arranged on the substrate, a pressure sensing upper polar plate is arranged above the lower polar plate, and a cavity is arranged between the upper polar plate and the lower polar plate; a pressure inlet chamber is arranged on the substrate; a pressure inlet chamber is arranged below the pressure sensing lower polar plate; the substrate is an annular substrate with the middle part opened;

a cushion block is arranged at the lower end of the substrate; or a clamping groove which can enable the chip to be suspended in the air and enable the lower polar plate to sense pressure is arranged on the substrate opened in the middle.

2. The capacitive pressure sensitive chip of claim 1, wherein the substrate is a single crystal silicon or polysilicon or a glass or ceramic substrate.

3. The capacitive pressure sensitive chip according to claim 1, wherein a dielectric layer is disposed on the pressure sensitive bottom plate.

4. The capacitive pressure sensitive chip according to claim 1, wherein the cavity is a sealed cavity.

5. The capacitive pressure sensitive chip according to claim 1, wherein the upper plate and the lower plate are connected to an external circuit through a bonding pad and a metal lead or a bonding pad.

6. The capacitive pressure sensitive chip according to claim 1, wherein the card slot is disposed at a lower end or a central portion of an outer periphery of the substrate.