CN220772418U

CN220772418U - Pressure sensor

Info

Publication number: CN220772418U
Application number: CN202321714568.0U
Authority: CN
Inventors: 王小平; 曹万; 杨军; 李凡亮; 王红明; 梁世豪
Original assignee: Wuhan Finemems Inc
Current assignee: Wuhan Finemems Inc
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2024-04-12
Anticipated expiration: 2033-06-30

Abstract

A pressure sensor capable of improving a drop between a pressure measurement assembly and a pin to meet bonding requirements, comprising: a housing defining a mounting cavity; the pressure measurement assembly is arranged in the mounting cavity and comprises a substrate for dividing the mounting cavity into a front side cavity and a back side cavity and a pressure element for blocking one front end of a pressure hole formed in the substrate, a processing circuit and a plurality of bonding pads connected with the processing circuit are arranged on the front side of the substrate, one back end of the pressure hole is communicated to the back side cavity, and the pressure element is electrically connected with the processing circuit; a plurality of pressure ports connected to the backside cavity; a plurality of contact pins fixed on the shell and arranged corresponding to the plurality of bonding pads, wherein one end of the inner side of the contact pins extends into the positive side cavity and is provided with a connecting plane; at least one metal gasket; and one end of the bonding wire is connected to the connecting plane or the corresponding metal gasket surface, the other end of the bonding wire is connected to the bonding pad surface or the corresponding metal gasket surface, and at least one end of the bonding wire is connected with one metal gasket.

Description

Pressure sensor

Technical Field

The application relates to the technical field of sensors, in particular to a pressure sensor.

Background

Pressure sensors are used to measure the pressure of a fluid and generally include a housing for forming an internal cavity, and a pressure measurement assembly disposed within the housing, wherein the pressure measurement assembly is required to be powered by a pin and output a measurement signal to an external device. The bonding pads of the pressure measurement assembly are typically connected to the pins by bonding wires using a bonding machine, and the drop between bonding planes should be limited to typically within 2 millimeters. Because the measurement conditions, the electrical interfaces and the mechanical installation modes of different devices are mostly different, the pressure sensor needs to be specially designed according to different use requirements. For small volume pressure sensor manufacturing, the die cost is relatively expensive. Thus, it is sometimes necessary to verify and/or mass manufacture the pressure sensor housing with other similar structural parameters, but the planar drop of the pad surface to the pin surface is not always satisfactory for bonding.

The statements in this section merely provide background information related to the present application and may not constitute prior art.

Disclosure of Invention

In response to the deficiencies of the prior art, the present application is directed to providing a pressure sensor that enables the head between the pressure measurement assembly and the pin to be improved so that it meets the bonding requirements.

The pressure sensor provided by the application comprises: a housing defining a mounting cavity; the pressure measurement assembly is arranged in the mounting cavity and comprises a substrate for dividing the mounting cavity into a front side cavity and a back side cavity and a pressure element for blocking one front end of a pressure hole formed in the substrate, a processing circuit and a plurality of bonding pads connected with the processing circuit are arranged on the front side of the substrate, one back end of the pressure hole is communicated to the back side cavity, and the pressure element is electrically connected with the processing circuit; a plurality of pressure ports connected to the backside cavity; a plurality of contact pins fixed on the shell and arranged corresponding to the plurality of bonding pads, wherein one end of the inner side of the contact pins extends into the positive side cavity and is provided with a connecting plane; the metal gaskets comprise first metal gaskets welded on the connecting plane and/or second metal gaskets welded on the surfaces of the corresponding bonding pads; and a bonding wire which connects the bonding pad and the connection plug correspondingly, wherein one end of the bonding wire is connected with the corresponding connection plane or the surface of the metal gasket arranged on the corresponding connection plane, the other end of the bonding wire is connected with the corresponding bonding pad surface or the surface of the metal gasket arranged on the corresponding bonding pad surface, and at least one end of the bonding wire is connected with one metal gasket.

Preferably, the connection plane and/or the pad surface of the pin is provided with a positioning structure for positioning the metal pad.

Preferably, the positioning structure is a groove matched with the shape of the metal gasket, and the metal gasket is arranged in the groove through soldering.

Preferably, the bonding wire and the metal pad are both aluminum.

Preferably, the bonding wire is an aluminum tape.

Preferably, the shell comprises a main shell body with a first opening at one forward side and a first cover body which is buckled on the first opening in a sealing way.

Preferably, the shell further comprises a second cover body which is buckled on a second opening formed in the back side of the main shell in a sealing way, the main shell comprises a first cavity and a second cavity which are isolated from each other, the first cavity is communicated with the pressure hole, and the second cavity is communicated to the positive side cavity; the plurality of pressure interfaces includes a first pressure interface that communicates with the first chamber and a second pressure interface that communicates with the second chamber.

Preferably, the pressure element is a semiconductor pressure chip.

Preferably, the front face of the base plate is fixed with a frame surrounding the pressure element, and the frame is filled with a protective gel covering the pressure element.

Preferably, the back surface of the substrate is supported on a first supporting surface formed on the housing, the back surface of the inner end of the pin is supported on a second supporting surface formed on the housing, and a partition groove is formed on the housing to be partitioned between the first supporting surface and the second supporting surface.

Drawings

FIG. 1 is a schematic top view of a pressure sensor according to a preferred embodiment of the present utility model (with the first cover removed);

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1;

FIG. 3 is an enlarged schematic view of the portion B shown in FIG. 2;

FIG. 4 is an enlarged schematic view of the portion C shown in FIG. 1;

in the figure: 100. a backside cavity; 10. a main housing; 11. a partition groove; 12. a connection part; 13. a second cover; 14. a bushing; 1a, positive side cavity; 1b, a first cavity; 1c, a second cavity; 1. a housing; 20. a substrate; 21. a pressure element; 22. a conditioning element; 23. a bonding pad; 24. a frame; 25. protecting the gel; 26. a pressure hole; 2. a pressure measurement assembly; 3. an end button; 41. an inner section; 42. a middle section; 43. an outer section; 44. a groove; 4. a contact pin; 5. bonding wires; 6a, a first pressure interface; 6b, a second pressure interface; 6. a metal gasket;

Detailed Description

The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. The following examples are illustrative only and are not to be construed as limiting the present application. In the following description, the same reference numerals are used to designate the same or equivalent elements, and duplicate descriptions are omitted.

In the description of the present application, it should be understood that the azimuth or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. are based on the azimuth or positional relationship shown in the drawings, or the azimuth or positional relationship in which the product of the present application is conventionally put in use, or the azimuth or positional relationship as is conventionally understood by those skilled in the art, are merely for convenience of description of the present application and for simplification of description, and are not indicative or implying that the apparatus or element to be referred to must have a specific azimuth, be configured and operated in a specific azimuth, and therefore should not be construed as limiting the present application.

In addition, the terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application can be understood as appropriate by one of ordinary skill in the art.

It should be further understood that the term "and/or" as used in this specification and the corresponding claims refers to any and all possible combinations of one or more of the listed items.

As shown in fig. 1 to 4. In a preferred embodiment of the present application, the pressure sensor comprises a housing 1 and a pressure measuring assembly 2. Wherein the housing 1 defines a mounting cavity for mounting the pressure measuring assembly 2. The pressure measuring component 2 is arranged in the mounting chamber and comprises a base plate 20 and a pressure element 21. The base plate 20 divides the mounting cavity into a front side cavity 1a and a back side cavity 100, and the pressure element 21 is plugged at a forward end of a pressure hole 26 formed in the base plate 20. The substrate 20 is preferably a ceramic plate such as an aluminum oxide plate, an aluminum nitride plate, a magnesium oxide plate, or the like. The front surface of the substrate 20 is provided with a processing circuit and a pad 23 connected to the processing circuit. The opposite end of the pressure port 26 communicates with the backside chamber 100. The pressure element 21 is electrically connected to the processing circuit. These processing circuits may include conditioning elements 22 and other circuit elements. The processing circuit is electrically connected to a plurality of pads 23 provided on the front surface of the substrate 20.

The pressure sensor further comprises a first pressure port 6a connected to the housing 1, the first pressure port 6a being connected to the back side chamber 100 for introducing a pressure medium to be measured into the back side chamber 100.

The shell 1 is fixedly provided with a plurality of contact pins 4 which sequentially comprise an inner section 41, a middle section 42 and an outer section 43 from inside to outside. The inner section 41 extends into the front side chamber 1a and has a connection plane protruding from the housing 1 toward the front side, the middle section 42 is embedded in the housing 1, and the outer section 43 extends into the end button 3 integrally connected to the housing 1. A metal pad 6 is welded to each connection plane. The metal pad 6 and the bonding pad 23 are electrically connected by a bonding wire 5.

The pressure sensor can be welded to the front surface of the inner end of the pin 4 by selecting a metal pad 6 with a proper thickness, so that the drop between the front surface of the metal pad 6 and the bonding pad 23 is suitable for connection by the bonding wire 5.

In other embodiments, it is preferable that the connection plane of the pin 4 is provided with a positioning structure for positioning the metal pad 6. For example, the positioning structure may be a groove 44 (see fig. 4) adapted to the shape of the metal pad 6, and the metal pad 6 is disposed in the groove 44 by soldering. Preferably, the bonding wire 5 and the metal pad 6 are both made of aluminum, and more preferably, the bonding wire 5 may be an aluminum tape, and a flat surface of the aluminum tape is bonded to the bonding pad 23 and the metal pad 6.

In other embodiments, the housing 1 may preferably include a main casing 10 having a first opening provided at a forward side thereof and a first cover (not shown) sealingly engaged with the first opening. In other preferred embodiments, the main housing 10 includes a first chamber 1b and a second chamber 1c that are isolated, and the first chamber 1b communicates with the pressure hole 26, so that pressure sensing surfaces on both sides of the pressure element 21 (e.g., a differential pressure chip or a gauge pressure chip) respectively receive pressures of two pressure interfaces to measure a pressure difference thereof, and the pressure sensor may be referred to as a differential pressure sensor; when one of the pressures is atmospheric, the pressure sensor may be referred to as a gauge pressure sensor. The second chamber 1c communicates with the positive side chamber 1a. The number of pressure interfaces comprises a first pressure interface 6a communicating to the first chamber 1b and a second pressure interface 6b communicating to the second chamber 1 c. The housing 1 may further include a second cover 13 that is sealed and fastened to a second opening formed on the back side of the main housing 10, so that the first cavity 1b and the second cavity 1c are named for molding with plastic. The first pressure port 6a and the second pressure port 6b are integrally connected to the main casing 10. The end button 3 is integrally connected to one end of the main casing 10, a connecting portion 12 is formed at the other end of the main casing 10 away from the end button 3, a connecting mounting hole (not labeled) is formed in the connecting portion 12, and a bushing 14 is fixed in the mounting hole to be connected with the equipment through a fastener.

In the above embodiments, the pressure element 21 may be a semiconductor pressure chip, a strain gauge, or the like. Preferably, the pressure element 21 is a semiconductor pressure chip. The front face of the base plate 20 may be fixed with a frame 24 surrounding the pressure element 21. The housing 24 is filled with a protective gel 25 covering the pressure element 21. The pressure port 26 may also be filled with a protective gel. The back surface of the substrate 20 may be supported on a first supporting surface formed on the housing 1. The back surface of the inner end of the pin 4 may be supported on a second support surface formed on the housing 1. The housing 1 is formed with a separation groove 11 which is cut off between the first support surface and the second support surface, so that when the substrate 20 is adhered to the first support surface by glue, the overflowed glue can be contained to avoid contaminating the bonding surface.

Not shown in the figures, in other embodiments, one of ordinary skill in the art may alternatively or additionally provide one of the above-described metal pads on the surface of the pads 23 of the substrate 20 in light of the above description. The surface of the bonding pad 23 can be correspondingly provided with a positioning structure for positioning the metal pad (6). This also enables the difference in height between the ends of the wire to be kept small during wire bonding. In addition, when metal gaskets are provided at both ends of the bonding wire 5, the risk of contamination of the bonding surface with glue can be better avoided.

The scope of the present disclosure is defined not by the detailed description but by the claims and their equivalents, and all modifications within the scope of the claims and their equivalents are to be construed as being included in the present disclosure.

Claims

1. A pressure sensor, comprising:

a housing (1) defining a mounting cavity;

the pressure measurement assembly (2) is arranged in the mounting cavity and comprises a substrate (20) for dividing the mounting cavity into a front side cavity (1 a) and a back side cavity (100) and a pressure element (21) for blocking one forward end of a pressure hole (26) formed in the substrate (20), a processing circuit and a plurality of bonding pads (23) connected with the processing circuit are arranged on the front side of the substrate (20), one back end of the pressure hole (26) is communicated to the back side cavity (100), and the pressure element (21) is electrically connected with the processing circuit;

a plurality of pressure ports that communicate to the backside cavity (100);

a plurality of contact pins (4) fixed on the shell (1) and arranged corresponding to the plurality of bonding pads (23), and one end of the inner side of the contact pins extends into the positive side cavity (1 a) and is provided with a connecting plane;

a metal pad (6) comprising a first metal pad welded to the connection plane and/or a second metal pad welded to the surface of the corresponding pad (23);

and a bonding wire (5) correspondingly connecting the bonding pad (23) and the connection pin (4), wherein one end of the bonding wire is connected with the corresponding connection plane or the surface of the metal gasket arranged on the corresponding connection plane, the other end of the bonding wire is connected with the surface of the corresponding bonding pad (23) or the surface of the metal gasket arranged on the surface of the corresponding bonding pad (23), and at least one end of the bonding wire (5) is connected with one metal gasket.

2. Pressure sensor according to claim 1, characterized in that the connection plane of the pins (4) and/or the surface of the corresponding pads (23) are provided with positioning structures for positioning the metal pads (6).

3. Pressure sensor according to claim 2, characterized in that the positioning structure is a groove (44) adapted to the shape of the metal gasket (6), the metal gasket (6) being arranged in the groove (44) by soldering.

4. Pressure sensor according to claim 1, characterized in that the bonding wire (5) and the metal pad (6) are both aluminum.

5. Pressure sensor according to claim 4, characterized in that the bonding wire (5) is an aluminum strip.

6. Pressure sensor according to any of claims 1 to 5, characterized in that the housing (1) comprises a main housing (10) provided with a first opening on the forward side and a first cover which is sealed and snapped onto the first opening.

7. The pressure sensor according to claim 6, wherein the housing (1) further comprises a second cover (13) sealingly fastened to a second opening formed in the back side of the main housing (10), the main housing (10) comprising a first cavity (1 b) and a second cavity (1 c) isolated from each other, the first cavity (1 b) being in communication with the pressure hole (26), the second cavity (1 c) being in communication with the front side cavity (1 a); the plurality of pressure interfaces comprises a first pressure interface (6 a) communicated to the first cavity (1 b) and a second pressure interface (6 b) communicated to the second cavity (1 c).

8. Pressure sensor according to any of claims 1 to 5, characterized in that the pressure element (21) is a semiconductor pressure chip.

9. Pressure sensor according to any of claims 1 to 5, characterized in that a frame (24) surrounding the pressure element (21) is fixed to the front side of the base plate (20), and that a protective gel (25) covering the pressure element (21) is filled in the frame (24).

10. Pressure sensor according to any of claims 1 to 5, characterized in that the back side of the substrate (20) is supported on a first support surface formed on the housing (1), the back side of the inner end of the pin (4) is supported on a second support surface formed on the housing (1), and a partition (11) is formed on the housing (1) which is partitioned between the first support surface and the second support surface.