CN212988661U

CN212988661U - MEMS pressure chip

Info

Publication number: CN212988661U
Application number: CN202021751220.5U
Authority: CN
Inventors: 聂泳忠; 吴桂珊; 李腾跃; 卢法光
Original assignee: Xirenma Combined Measurement And Control Quanzhou Technology Co ltd
Current assignee: Xirenma Combined Measurement And Control Quanzhou Technology Co ltd
Priority date: 2020-08-20
Filing date: 2020-08-20
Publication date: 2021-04-16
Anticipated expiration: 2030-08-20

Abstract

The utility model discloses a MEMS pressure chip, MEMS pressure chip includes the supporting part, response layer and truss structure, the supporting part has logical chamber, the response layer is unsettled in logical chamber and includes bed frame and two at least corbels through supporting part support truss structure, be equipped with first fretwork region on the bed frame, the one end of each corbel is connected to the bed frame, the other end extends to the supporting part, make to enclose between corbel, the bed frame and the supporting part and establish and form two at least second fretwork regions, the response layer exposes through first fretwork region and second fretwork region. The utility model discloses can improve linearity, the temperature performance of wafing of pressure chip output and the performance of wafing in time to reduce the acceleration interference that causes because of the additional mass that truss structure introduced to pressure chip's output.

Description

MEMS pressure chip

Technical Field

The utility model relates to a micro-electromechanical system technical field, concretely relates to MEMS pressure chip.

Background

The pressure sensitive chip is a sensitive unit for converting a pressure signal into an electrical signal, and a Micro-Electro-Mechanical System (MEMS) pressure chip prepared by a semiconductor process has the advantages of miniaturization, low power consumption, low cost, good uniformity and convenience for mass production, so the MEMS pressure chip is widely applied to various fields of consumer electronics, medical electronics, industrial electronics, aerospace and the like.

Pressure chips for measuring pressure changes in a minute range (ranging from several hundred pascals to several tens of kilopascals) are generally collectively called as minute pressure chips, and since pressure changes in a minute range need to be measured, minute pressure chips should have extremely high sensitivity to have detectable voltage output changes under minute pressure changes, and at the same time, minute pressure chips should have good stability in order to ensure accuracy of output results.

Therefore, it is desirable to provide a MEMS pressure chip with high sensitivity and good stability.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides a MEMS pressure chip that sensitivity is high and stability is good.

The embodiment of the utility model provides a MEMS pressure chip, MEMS pressure chip includes: a support portion having a through cavity; the induction layer is suspended in the through cavity and supported by the support part; the truss structure is arranged on the surface of one side of the induction layer and comprises a base frame and at least two supporting beams, at least one first hollow area enabling the induction layer to be exposed is arranged on the base frame, one end of each supporting beam is connected to the base frame, the other end of each supporting beam extends to the supporting portion, and at least two second hollow areas enabling the induction layer to be exposed are formed by enclosing among the supporting beams, the base frame and the supporting portion.

According to one aspect of the embodiment of the present invention, the number of the support beams is two, and the two support beams extend in the same direction and are respectively disposed on both sides of the base frame; or the like, or, alternatively,

the number of the supporting beams is three, two of the supporting beams extend along a first direction and are respectively arranged on two sides of the base frame, and the extending direction of the other supporting beam is perpendicular to the first direction.

According to an aspect of the embodiment of the present invention, the cross section of the through cavity of the supporting portion is square, the number of the supporting beams is four, one end of each of the four supporting beams is connected to the base frame, and the other end of each of the four supporting beams extends to four sides of the supporting portion;

preferably, the base frame is arranged at the center of the induction layer, and the supporting beams are distributed around the base frame at equal intervals.

According to the utility model discloses an aspect, the figure of truss structure is at least two, and two truss structure intervals set up.

According to the utility model discloses an aspect, supporting part, response layer and truss structure formula structure as an organic whole.

According to an aspect of the embodiment of the present invention, the sensor further comprises a piezoresistor assembly, the piezoresistor assembly comprises a lead and a plurality of piezoresistors electrically connected through the lead, the piezoresistors are in contact connection with the sensing layer, and the piezoresistor assembly generates an electrical signal according to the deformation of the sensing layer;

preferably, each piezoresistor of the piezoresistor assembly is electrically connected into a Wheatstone bridge through a lead;

preferably, the piezoresistors are arranged in stress concentration zones of the truss structure.

According to an aspect of the embodiment of the present invention, the sensor further comprises a passivation layer, the passivation layer is located at one side of the sensing layer where the truss structure is arranged and covers the truss structure and the first surface of the supporting portion in the thickness direction of the sensor;

preferably, the passivation layer covering the support portion is provided with a connection hole exposing at least a portion of the lead, and a pad connected to the lead is formed in the connection hole.

According to an aspect of the embodiment of the utility model, still include the silicon oxidation layer, the silicon oxidation layer is located the first surface that the response layer was provided with one side of truss structure and covered truss structure and supporting part, and the silicon oxidation layer is located between the first surface and the passivation layer of supporting part.

According to the utility model discloses an aspect, the second surface that truss structure was kept away from to the supporting part is provided with the connection substrate, and the connection substrate seals to lead to the chamber and keeps away from the accent of truss structure one side.

According to the utility model discloses an aspect, the connection substrate has the external inlet channel who leads to the chamber of intercommunication, and on the plane of perpendicular to thickness direction, inlet channel's size is less than the size that leads to the chamber.

The embodiment of the utility model provides a MEMS pressure chip, MEMS pressure chip is including specifically having the supporting part that leads to the chamber and unsettled in the response layer that leads to the chamber and support through the supporting part, one side of response layer is provided with truss structure on the surface, truss structure includes bed frame and two at least corbels, be equipped with first fretwork region on the bed frame, the response layer exposes through first fretwork region, truss structure has increased the holistic rigidity of response layer and pressure chip's effective surface area, make the response layer be difficult for the thermal deformation, pressure chip changes the heat dissipation, consequently, the temperature that can improve pressure chip output can wafts the performance and when wafting the performance, in addition, be equipped with first fretwork region on truss structure's the bed frame, can reduce the acceleration interference that the additional quality that introduces because of truss structure causes pressure chip's output.

Drawings

Other features, objects and advantages of the invention will become apparent from the following detailed description of non-limiting embodiments thereof, when read in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof, and which are not to scale.

Fig. 1 is a schematic diagram illustrating a planar structure of a MEMS pressure chip according to an embodiment of the present invention;

FIG. 2 shows a schematic cross-sectional view at the location A-A in FIG. 1;

FIG. 3 shows a schematic cross-sectional view at the location B-B in FIG. 1;

FIG. 4 shows a schematic cross-sectional view at the position C-C in FIG. 1;

fig. 5 is a schematic diagram illustrating a layer structure of a MEMS pressure chip according to another embodiment of the present invention.

Description of reference numerals:

110-a support; 111-the back cavity;

120-a varistor assembly; 121-a lead; 122-a voltage dependent resistor;

130-a sensing layer;

140-truss structure; 141-a base frame; 142-corbel; 143-a first hollowed-out area; 144-a second hollowed-out area;

150-a passivation layer;

160-a pad;

20-a connection substrate; 201-air intake passage.

Detailed Description

The features and exemplary embodiments of various aspects of the present invention will be described in detail below, and in order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It will be apparent to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

It will be understood that when a layer, region or layer is referred to as being "on" or "over" another layer, region or layer in describing the structure of the component, it can be directly on the other layer, region or layer or intervening layers or regions may also be present. Also, if the component is turned over, one layer or region may be "under" or "beneath" another layer or region.

Referring to fig. 1 to 4, fig. 1 is a schematic diagram illustrating a planar structure of an MEMS pressure chip according to an embodiment of the present invention; FIG. 2 shows a schematic cross-sectional view at the location A-A in FIG. 1; FIG. 3 shows a schematic cross-sectional view at the location B-B in FIG. 1; fig. 4 shows a schematic cross-sectional view at the position C-C in fig. 1. The layer structure schematic diagram in the application is a schematic diagram on the structure principle, and the actual size, the detail position and the like of each part contained in the MEMS pressure chip can be adjusted according to the actual situation.

An embodiment of the present invention provides a MEMS pressure chip, which includes a supporting portion 110, an inductive layer 130 and a truss structure 140.

The supporting portion 110 has a through cavity, the sensing layer 130 is suspended in the through cavity and supported by the supporting portion 110, the truss structure 140 is disposed on a side surface of the sensing layer 130, the truss structure 140 includes a base frame 141 and at least two support beams 142, at least one first hollow area 143 for exposing the sensing layer 130 is disposed on the base frame 141, one end of each support beam 142 is connected to the base frame 141, and the other end extends to the supporting portion 110, so that at least two second hollow areas 144 for exposing the sensing layer 130 are defined between the support beams 142, the base frame 141, and the supporting portion 110.

According to the MEMS pressure chip provided by the embodiment of the present invention, the sensing layer 130 can be made very thin according to actual needs, so that the MEMS pressure chip has higher sensitivity, the truss structure 140 is disposed on the surface of one side of the sensing layer 130, the rigidity of the whole sensing layer 130 is increased, when the external environment temperature changes, the sensing layer 130 is not easily deformed by heat, and the temperature drift performance of the output of the pressure chip can be improved; in addition, the truss structure 140 increases the effective surface area of the pressure chip, is more conducive to heat dissipation of the chip, and can improve the time drift caused by resistance thermal power consumption.

In addition, the base frame 141 of the truss structure 140 has the first hollow area 143, which can reduce the additional mass introduced by the truss structure 140 and reduce the acceleration interference of the truss structure 140 to the output of the pressure chip.

It can be understood that, in the MEMS pressure chip provided in the embodiment of the present invention, the truss structure 140 includes a base frame 141 and a plurality of support beams 142, and the number of the support beams 142 can be selected according to actual needs, which is not specifically limited by the present application.

In some alternative embodiments, the truss structure 140 may include a base frame 141 and four support beams 142, the cross section of the through cavity of the support portion 110 may be square, the inner edge of the support portion 110 and the sensing layer 130 are both square, one end of each of the four support beams 142 is connected to the base frame 141, and the other end of each of the four support beams 142 may extend to four sides of the support portion 110, so that the rigidity of the whole sensing layer 130 can be maximized.

Alternatively, the base frame 141 may be disposed at the center of the sensing layer 130, and the four support beams 142 may be distributed around the base frame 141 at equal intervals, so that the truss structure 140 is overall cross-shaped. In addition, the outer and inner edges of the base frame 141 may be square, and one end of each of the joists 142 may be connected to the central position of the outer edge of the base frame 141 and the other end extends to the central position of the inner edge of the support part 110.

Alternatively, the number of the corbels 142 may be two, and the two corbels 142 may extend in the same direction and be disposed on two sides of the base frame 141 respectively.

Alternatively, the number of the corbels 142 may be three, two corbels 142 may extend along the first direction and are respectively disposed on two sides of the base frame 141, and the extending direction of the other corbel 142 may be perpendicular to the first direction. Of course, the three support beams 142 may also be distributed around the base frame 141 at equal intervals, and the present invention is also within the protection scope of the present invention.

In some optional embodiments, the MEMS pressure chip provided in the present invention may include a plurality of truss structures 140, optionally, the number of truss structures 140 may be two, and two truss structures 140 may be disposed at an interval.

In some optional embodiments, the MEMS pressure chip provided in the embodiment of the present invention may further include a piezo-resistor component 120, the piezo-resistor component 120 includes a lead 121 and a plurality of piezo-resistors 122 electrically connected through the lead 121, the piezo-resistor 122 is in contact with the sensing layer 130, and the piezo-resistor component 120 can generate an electrical signal according to the deformation of the sensing layer 130, thereby realizing the measurement of the relative external pressure.

As an optional implementation manner, the piezoresistor 122 may be disposed in the stress concentration region of the truss structure 140, and the performance index of the pressure chip when measuring a micro-range pressure change can be significantly improved, which is specifically represented as: when the pressure chip provided with the truss structure 140 and the pressure chip not provided with the truss structure 140 have the same sensitivity, the linearity characteristic of the pressure chip provided with the truss structure 140 may be more excellent.

Alternatively, the piezoresistor 122 may be provided at a connection position of the corbel 142 and the support 110. When the MEMS pressure chip is subjected to a pressure load, the stress is more concentrated at the connection position of the support beam 142 and the supporting portion 110.

Alternatively, the number of the support beams 142 may be the same as the number of the piezoresistors 122, and the piezoresistors 122 are arranged in one-to-one correspondence with the support beams 142.

The piezo-resistor assembly 120 includes a plurality of piezo-resistors 122, and in some alternative embodiments, the number of piezo-resistors 122 may be four, and the four piezo-resistors 122 may be electrically connected by wires 121 to form a wheatstone bridge, so that the pressure chip can accurately measure pressure changes.

Alternatively, when the piezoresistors 122 of the piezoresistor assembly 120 are electrically connected to form a wheatstone bridge through the leads 121, the cross section of the through cavity of the supporting part 110 is square, the piezoresistor 122 is disposed at the center of the inner edge of the supporting part 110, the truss structure 140 may include a base frame 141 and four support beams 142, one end of each support beam 142 is connected to the base frame 141, and the other end extends to the center of each of the four sides of the supporting part 110.

In some alternative embodiments, the support portion 110, the sensing layer 130 and the truss structure 140 of the MEMS pressure chip may be a one-piece structure with higher structural strength and stability. Alternatively, the supporting portion 110, the sensing layer 130 and the truss structure 140 of the MEMS pressure chip may be patterned from one supporting substrate to facilitate manufacturing and reduce manufacturing cost.

Alternatively, the support substrate may be an SOI (Silicon-On-Insulator) Silicon substrate.

Alternatively, the piezoresistors 122 can be formed by performing P-type light doping on a predetermined region selected on the first surface of the supporting portion 110 in the thickness direction thereof through an ion implantation or thermal diffusion process, the leads 121 can be formed by performing P-type heavy doping on a predetermined region selected on the first surface of the supporting portion 110 through an ion implantation or thermal diffusion process, and the leads 121 electrically connect the piezoresistors 122 to each other.

In some optional embodiments, the MEMS pressure chip provided in the present invention may further include a silicon oxide layer, which is located on the side of the sensing layer 130 where the truss structure 140 is disposed and covers the truss structure 140 and the first surface of the supporting portion 110. When the pressure chip is manufactured by using the silicon substrate, a silicon dioxide layer can be grown on the surface of the silicon substrate to form a silicon oxide layer, and then P-type doping is performed in the surface layer of the silicon substrate to form the lead 121 and the piezoresistor 122, so that the P-type doping is more uniform in the thickness direction of the silicon substrate, and the electrical properties of the lead 121 and the piezoresistor 122 are better.

In some optional embodiments, the MEMS pressure chip may further include a patterned passivation layer 150, and the patterned passivation layer 150 is located at a side of the sensing layer 130 where the truss structure 140 is disposed and covers at least the first surface of the supporting part 110. Alternatively, the passivation layer 150 may be composed of silicon oxide or silicon nitride, or may be a composite film of silicon oxide and silicon nitride.

A connection hole may be provided on the passivation layer 150 covering the support part 110, the connection hole exposing at least a portion of the lead 121, and a pad 160 connected to the lead 121 may be formed in the connection hole, the varistor assembly 120 being communicated with an external circuit through the pad 160.

Optionally, the material of the bonding pad 160 may be one or a combination of metals selected from Al, Cu, Ti, Ni, Ta, Au, Pt, and the like.

It can be understood that when the first surface of the supporting portion 110 and the surface of the truss structure 140 facing away from the sensing layer 130 are formed with a silicon oxide layer, the silicon oxide layer is located between the first surface of the supporting portion 110 and the passivation layer 150, and the connection hole penetrates through the passivation layer 150 and the silicon oxide layer.

In some alternative embodiments, the passivation layer 150 covers both the first surface of the support part 110 and the truss structure 140 to increase the rigidity of the truss structure 140.

Referring to fig. 5, fig. 5 is a schematic diagram illustrating a layer structure of a MEMS pressure chip according to another embodiment of the present invention.

In some optional embodiments, to further improve the temperature drift and the time drift stability of the pressure chip, a connection substrate 20 may be disposed on a second surface of the support portion 110 away from the truss structure 140, and the connection substrate 20 closes a cavity opening of the through cavity on a side away from the truss structure 140. The portion of the through cavity on the side of the sensing layer 30 remote from the truss structure 140 may be defined as the back cavity 111.

Alternatively, the connection substrate 20 may be a glass substrate. The connection substrate 20 may be bonded to the second surface of the support 110 through an anodic bonding process.

According to the above-mentioned the embodiment of the utility model provides a MEMS pressure chip, when connection substrate 20 seals the accent of back of the body chamber 111, the different atmospheric pressure of gas makes response layer 130 produce different deformation in the environment that pressure chip is located, and the response layer 130 of different deformation volume makes the piezo-resistor subassembly 120 of being connected with response layer 130 produce different signals of telecommunication, and then realizes the measurement to external pressure. The electrical signal may be a change signal in the resistance value of the piezo 122 of the piezo-resistive assembly 120.

In some alternative embodiments, the connection substrate 20 has a gas inlet passage 201 communicating the outside with the back cavity 111, and the size of the gas inlet passage 201 is smaller than that of the back cavity 111 in a plane perpendicular to the thickness direction.

When inlet channel 201 communicates the external world with back of the body chamber 111, the gas in the environment that the pressure chip is located can get into the back of the body chamber 111 of supporting part 110 through inlet channel 201, and the different atmospheric pressure difference in response layer 130 both sides makes response layer 130 produce different deformations, and piezo-resistor subassembly 120 of being connected with response layer 130 then can produce different signals of telecommunication, and then realizes the measurement to relative pressure.

In accordance with the embodiments of the present invention as set forth above, these embodiments do not set forth all of the details nor limit the invention to the specific embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and its various embodiments with various modifications as are suited to the particular use contemplated. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A MEMS pressure chip, comprising:

a support portion having a through cavity;

the induction layer is suspended in the through cavity and supported by the supporting part;

the truss structure is arranged on the surface of one side of the sensing layer and comprises a base frame and at least two supporting beams, at least one first hollow area enabling the sensing layer to be exposed is arranged on the base frame, one end of each supporting beam is connected to the base frame, the other end of each supporting beam extends to the supporting portion, and therefore at least two second hollow areas enabling the sensing layer to be exposed are formed among the supporting beams, the base frame and the supporting portion in an enclosing mode.

2. The MEMS pressure chip of claim 1, wherein the number of the support beams is two, and the two support beams extend in the same direction and are respectively disposed on two sides of the base frame; or the like, or, alternatively,

3. The MEMS pressure chip of claim 1, wherein the cross section of the through cavity of the support portion is square, the number of the support beams is four, one end of each of the four support beams is connected to the base frame, and the other end of each of the four support beams extends to four sides of the support portion.

4. The MEMS pressure chip of claim 1, wherein the pedestal is disposed at a center of the sensing layer, and the support beams are equally spaced around the pedestal.

5. The MEMS pressure chip of claim 1, wherein the number of truss structures is at least two, and the two truss structures are spaced apart.

6. The MEMS pressure chip of any of claims 1 to 5, wherein the support portion, the sensing layer, and the truss structure are a unitary structure.

7. The MEMS pressure chip of any one of claims 1 to 5, further comprising a piezoresistor assembly, wherein the piezoresistor assembly comprises a lead and a plurality of piezoresistors electrically connected through the lead, the piezoresistors are in contact connection with the sensing layer, and the piezoresistor assembly generates an electrical signal according to the deformation of the sensing layer.

8. The MEMS pressure chip of claim 7, wherein each of the piezoresistors of the piezoresistor assembly is electrically connected as a wheatstone bridge by the wire.

9. The MEMS pressure chip of claim 7, wherein the piezoresistors are disposed in stress concentration regions of the truss structure.

10. The MEMS pressure chip of claim 7, further comprising a passivation layer on a side of the sensing layer where the truss structure is disposed and covering the truss structure and the first surface of the support portion in its thickness direction.

11. The MEMS pressure chip of claim 10, wherein the passivation layer covering the support portion is provided with a connection hole exposing at least a portion of the lead, the connection hole having a pad formed therein to be connected to the lead.

12. The MEMS pressure chip of claim 10, further comprising a silicon oxide layer on a side of the sensing layer on which the truss structure is disposed and covering the truss structure and the first surface of the support portion, the silicon oxide layer being between the first surface of the support portion and the passivation layer.

13. The MEMS pressure chip of any of claims 1 to 5, wherein a second surface of the support portion remote from the truss structure is provided with a connection substrate that closes a port of the through cavity on a side remote from the truss structure.

14. The MEMS pressure chip of claim 13, wherein the connection substrate has a gas inlet channel communicating with the outside and the through cavity, and a size of the gas inlet channel is smaller than a size of the through cavity in a plane perpendicular to a thickness direction.