CN211373906U

CN211373906U - Pressure sensor

Info

Publication number: CN211373906U
Application number: CN202021479529.3U
Authority: CN
Inventors: 娄帅
Original assignee: Nanjing Xinligan Electronic Technology Co ltd
Current assignee: Nanjing Xinligan Electronic Technology Co ltd
Priority date: 2020-07-24
Filing date: 2020-07-24
Publication date: 2020-08-28
Anticipated expiration: 2030-07-24

Abstract

The utility model provides a pressure sensor, including the substrate, be located the support of substrate top to and be used for the pressure sensitive diaphragm of induced pressure, still including the pressure processing subassembly that is used for receiving and handling the pressure signal that the pressure sensitive diaphragm sensed, be equipped with conductive component in the support, conductive component's one end with pressure processing subassembly connects, and conductive component's the other end extends to the outside of support, the substrate is equipped with an opening chamber, and the opening direction in opening chamber dorsad conductive component's extending direction, be equipped with the pressure sensitive diaphragm in the opening chamber, be equipped with a vacuum cavity among the pressure sensor, be equipped with the pressure drag diaphragm in the vacuum cavity, the pressure drag diaphragm is used for the protection the pressure processing subassembly, pressure sensor passes through conductive component or conductive component with the substrate is together packaged. The pressure sensor can be packaged in different modes, and the use requirements of different environments are met.

Description

Pressure sensor

Technical Field

The utility model relates to a pressure sensing technical field, in particular to pressure sensor.

Background

The pressure sensor has wide application in various fields such as industrial production, medical care and health, environmental monitoring, scientific research and the like, and the basic principle of the pressure sensor is to convert a pressure change value into a change of an electric signal. The pressure sensor is utilized to integrate the acquisition, processing and execution of the pressure change information together to form a multifunctional composite micro intelligent system, which not only can reduce the cost of the whole electromechanical system, but also can complete the tasks which can not be completed by a large-size electromechanical system; in addition, the pressure sensor can be embedded into a large-size system, so that the automation, intelligence and reliability level of the system are greatly improved. The pressure sensor is a microminiaturization result on the traditional machinery and is an important component of the whole nanometer science and technology. In recent years, silicon piezoresistive pressure sensors manufactured by adopting an MEMS (micro-electromechanical systems) process have the characteristics of small volume, high precision, low cost and the like, and are widely applied to the industrial field.

When the pressure sensor is used for pressure measurement, the sensor chip of the pressure sensor must be directly exposed to various harsh environments to be measured, which requires that the package of the pressure sensor can both protect the chip and actually transmit pressure, and therefore, the package requirement and difficulty are high. The reliability of the pressure sensor depends on the reliability of the package to a great extent, so that the design of the package structure and the process of the pressure sensor is very important.

For a silicon piezoresistive pressure sensor manufactured by adopting an MEMS (micro-electromechanical systems) process, a packaging mode that a pressure sensing surface is directly adhered to a measured medium or the back of a chip is generally adopted at present, and the packaging requirements under various environments are difficult to meet by the conventional packaging mode due to different use environments of the pressure sensor.

Disclosure of Invention

Based on this, the utility model aims at providing a can adopt different modes to carry out the pressure sensor who encapsulates.

A pressure sensor comprises a substrate, a support above the substrate, a pressure sensitive diaphragm sensing pressure, and a pressure processing assembly receiving and processing pressure signals sensed by the pressure sensitive diaphragm, a conductive component is arranged in the support, one end of the conductive component is connected with the pressure processing component, the other end of the conductive component extends to the outside of the support, the substrate is provided with an open cavity, the opening direction of the opening cavity is back to the extending direction of the conductive component, a pressure sensitive membrane is arranged in the opening cavity, the pressure sensor is internally provided with a vacuum cavity, the vacuum cavity is internally provided with a piezoresistive membrane, the piezoresistive membrane is used for protecting the pressure processing assembly, the pressure sensor is packaged together with the substrate through the conductive component or the conductive component.

In the above scheme, the pressure drag diaphragm in the vacuum cavity plays the guard action to pressure processing assembly, conducting component communicates pressure processing assembly and outside, the support can be kept apart the stress of sensing, thereby whole guard action that plays of pressure sensors, make pressure sensors can adapt to different environment, in concrete encapsulation, can only encapsulate through conducting component also can together encapsulate through conducting component and substrate, make in the face of different environment, can choose for use more suitable encapsulation mode, satisfy user's user demand.

Furthermore, an insulating layer is arranged between the substrate and the support, the pressure processing assembly comprises a piezoresistor and an electrode connected with the piezoresistor, the electrode and the piezoresistor are fixed on the substrate, the orifice of the vacuum cavity faces the insulating layer, and the piezoresistor, the electrode and the insulating layer are attached.

Further, the conductive assembly comprises a conductive column, and a first conductive gasket and a second conductive gasket which are respectively arranged at two ends of the conductive column, the first conductive gasket penetrates through the insulating layer and is connected with the electrode, the second conductive gasket is arranged at the outer side of the support, the pressure sensor is packaged through the second conductive gasket, and when the length and width of the pressure processing assembly is smaller than 1.6 x 1.6mm, the larger center distance between the two groups of second conductive gaskets is larger than 1.1 mm.

Furthermore, the conductive column comprises a metal layer and a filling layer, a through hole is formed in the support, the metal layer is coated on the surface of the through hole, the filling layer is filled in the through hole, and the depth-to-width ratio of the through hole is larger than or equal to 3: 1.

Furthermore, the shape of the open cavity is trapezoidal or rectangular, and the bottom of the open cavity is provided with a fillet structure.

Furthermore, one side of support is equipped with conducting material, electrically conductive component passes through conducting material and external equipment electric connection, the support is fixed to through the mode of welding or adhesion on the external equipment.

Furthermore, the part of the conductive component, which is positioned outside the support, is connected with a lead, a base is fixed at the bottom of the substrate, and a via hole is formed in the base and enables the pressure sensitive membrane to be communicated with the outside.

Furthermore, the outside of the support is provided with a solder ball tightly attached to the conductive component.

Furthermore, the solder balls are welded on the circuit board.

Furthermore, the solder ball is welded on the glass sealing conductive column.

Further, the substrate is bonded with the support, and the substrate and the surface of the support are both subjected to polishing treatment.

Drawings

Fig. 1 is a schematic structural diagram of a pressure sensor according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of a substrate and a pressure processing assembly of a pressure sensor according to a first embodiment of the present invention;

fig. 3 is a schematic structural view of a conductive assembly according to a first embodiment of the present invention;

fig. 4 is a schematic structural diagram of a pressure sensor in a first embodiment of the present invention;

fig. 5 is a schematic structural diagram of a pressure sensor in a second embodiment of the present invention;

fig. 6 is a schematic structural view of a pressure sensor in a third embodiment of the present invention;

fig. 7 is a schematic structural diagram of a pressure sensor in a third embodiment of the present invention.

Description of the symbols of the main elements

A substrate-10; a support-20; pressure treatment assembly-30; -40 an electrically conductive member; an insulating layer-50; a pressure sensitive diaphragm-60; a varistor-31; an electrode-32; a first conductive pad-41; a conductive post-42; a second conductive pad-43; a vacuum chamber-21; an open cavity-11; a metal layer-421; a fill layer-422; a base-70; a via-71; a wire-72; solder ball-80; a circuit board-81; glass seal conductive post-82; conductive adhesive-83.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. Several embodiments of the invention are given in the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. As used herein, the terms "vertical," "horizontal," "left," "right," "up," "down," and the like are for illustrative purposes only and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1-4, a pressure sensor according to a first embodiment of the present invention is shown, including a substrate 10, a support 20 located above the substrate 10, and a pressure processing assembly 30 for sensing and processing pressure, a conductive assembly 40 is disposed in the support 20, one end of the conductive assembly 40 is connected to the pressure processing assembly 30, the other end of the conductive assembly 40 extends to the outside of the support 20, the substrate 10 is provided with an open cavity 11, an opening direction of the open cavity 11 faces away from an extending direction of the conductive assembly 40, a pressure sensitive membrane 60 is disposed in the open cavity 11, and the pressure sensor is packaged together with the substrate 10 through the conductive assembly 40 or the conductive assembly 40.

In order to protect the pressure processing assembly 30 and to adapt the pressure sensor to various environments, a vacuum chamber 21 is disposed in the pressure sensor, and a piezoresistive membrane is disposed in the vacuum chamber 21 and used for protecting the pressure processing assembly 30, and when the pressure processing assembly 30 is disposed, the vacuum chamber 21 is located above or below the pressure processing assembly 30, specifically, one side of the etching support 20 or one side of the substrate 10.

In this embodiment, the pressure drag diaphragm in the vacuum cavity 21 plays the guard action to pressure processing assembly 30, conductive component 40 communicates pressure processing assembly 30 with the outside, support 20 can keep apart the stress of sensing, thereby play the guard action to pressure sensor is whole, make pressure sensor can adapt to different environment, in concrete encapsulation, can only encapsulate through conductive component 40 and also can encapsulate together through conductive component 40 and substrate 10, make in the face of different environment, can choose for use more suitable encapsulation mode, satisfy user's user demand.

In this embodiment, regarding the portion of the pressure processing assembly 30, an insulating layer 50 is disposed between the substrate 10 and the support 20, the pressure processing assembly 30 further includes a pressure sensitive resistor 31 and an electrode 32 connected to the pressure sensitive resistor 31, the electrode 32 and the pressure sensitive resistor 31 are fixed on the substrate 10, the opening of the vacuum chamber 21 faces the insulating layer 50, and the pressure sensitive resistor 31, the electrode 32 and the insulating layer 50 are attached.

Specifically, in the manufacturing process:

a varistor 31 and an extraction electrode 32 are formed on a substrate 10, and a device layer is formed by implanting silicon ions doped with a low-concentration boron element into one surface of the substrate 10.

The piezoresistor 31 is patterned, that is, the device layer of the non-resistor bar pattern part in the device region is etched away by adopting an etching process to manufacture the piezoresistor 31.

And forming a deposition passivation layer to protect the piezoresistor 31, namely sequentially depositing SiO2 and Si3N4 by adopting a PECVD (plasma enhanced chemical vapor deposition) process to manufacture a passivation protection layer of the piezoresistor 31.

And etching the ohmic contact area, namely etching the passivation layer of the ohmic contact area between the tops of the piezoresistors 31 and the metal lead by adopting an etching process, and heavily doping the ohmic contact area by adopting an ion implantation process in order to reduce the contact impedance between the metal lead and the piezoresistor 31.

And manufacturing a metal lead, namely manufacturing the metal lead and a lead bonding pad by sequentially sputtering three layers of metals such as Ti, Pt, Au and the like by adopting a sputtering process, wherein Ti is an adhesion layer, Pt is a barrier layer, and Au is a passivation conducting layer. And then forming alloy on the ohmic contact area of the metal lead wire and the resistance strip through a rapid annealing process, so as to reduce the interface contact resistance. In actual production, other MEMS electrode materials can be selected according to the situation to be manufactured.

In this embodiment, regarding the part of the conductive assembly 40, the conductive assembly 40 includes a conductive pillar 42 and a first conductive pad 41 and a second conductive pad 43 respectively located at two ends of the conductive pillar 42, the first conductive pad 41 penetrates through the insulating layer 50 and is connected to the electrode 32, the second conductive pad 43 is located at the outer side of the support 20, and the pressure sensor is packaged by the second conductive pad 43.

It can be understood that, after the above-mentioned fabrication, the piezoresistor 31 and the electrode 32 are located on the surface layer of the substrate 10, and then the insulating layer 50 is disposed above the piezoresistor 31 and the electrode 32, the insulating layer 50 is provided with a through hole, and the first conductive pad 41 is located in the through hole, so as to electrically connect the conductive pillar 42 and the electrode 32.

In addition, the conductive column 42 includes a metal layer and a filling layer, a through hole is formed in the support 20, the metal layer 421 is coated on the surface of the through hole, and the filling layer 422 is filled in the through hole.

In the specific manufacturing of the through hole on the support 20 and the first conductive gasket 41:

forming a through-hole on the support 20 by a deep reactive ion etching process;

depositing insulating layer 50 materials such as SiO2, Si3N4 and the like by a PECVD process;

depositing a metal adhesion layer/barrier layer/seed layer on the through hole and the lower surface by PVD, PECVD or magnetron sputtering technology;

filling the through hole with organic epoxy;

flattening the surface of the wafer by polishing or grinding;

patterning the electrode 32 by a photolithography and etching process;

a first conductive pad 41 and a second conductive pad 43 are formed on the through hole.

In this embodiment, the through holes are through silicon holes, and the conductive elements 40 disposed in the through holes need to be protected from external stress, so that a larger diameter of the through silicon hole is needed, and the aspect ratio of the through holes is greater than or equal to 3: 1. The filling layer 422 is filled with organic epoxy or other organic insulating materials, so that cracking of the metal layer 421 caused by inconsistent thermal expansion coefficients of different metals in the metal layer 421 can be avoided, and the filling layer is particularly important for large-diameter through silicon vias. The first conductive pad 41 and the second conductive pad 43 may be disposed outside the through hole or inside the through hole, and the first conductive pad 41 and the second conductive pad 43 may be formed outside the through hole under the condition that the pressure processing assembly 30 has a small size, specifically, a length and a width of less than 1.6 × 1.6 mm.

In this embodiment, the first conductive pads 41 and the second conductive pads 43 are located outside the through holes, and at least two sets of through holes are provided on the support 20, and a set of conductive assemblies 40 is correspondingly provided in each through hole, so that a larger distance can be maintained between the two sets of through holes under the condition that the pressure processing assembly 30 has a smaller size as described above, and further, the distance between the two sets of second conductive pads 43 is larger than 1.1mm, thereby facilitating the subsequent packaging on the component.

Regarding the part of the pressure sensitive membrane 60, during the specific manufacturing, in this embodiment, the substrate 10 is etched back to form a cavity structure, i.e. the open cavity 11, and then the pressure sensitive membrane 60 is manufactured to a required thickness, where the thickness of the pressure sensitive membrane 60 is set according to the size of the cavity and the size of the pressure range. The shape of the open cavity 11 may be rectangular, trapezoidal or other realizable shape structure, and in this embodiment, the open cavity 11 is trapezoidal, and specifically, the open cavity 11 is gradually narrowed from the cavity mouth to the cavity bottom. And in order to better mount the pressure sensitive diaphragm 60, the cavity bottom of the open cavity is provided with a rounded corner structure in the present embodiment.

In addition, in this embodiment, the substrate 10 is bonded to the support 20, the surfaces of the substrate 10 and the support 20 are both subjected to polishing treatment, and the roughness of both is less than 2nm, and the piezoresistor 31, the electrode 32 and the like to be bonded are subjected to wet chemical cleaning. And aligning and attaching the piezoresistor 31 and the electrode 32 which are subjected to wet chemical cleaning and plasma treatment by using the positioning alignment function of a double-sided photoetching machine for fusion silicon bonding.

In this embodiment, the pressure sensor is packaged by the conductive component 40, specifically, a conductive material is disposed on one side of the support 20 where the second conductive pad 43 is disposed, the support 20 is fixed to an external device by welding or adhering, the conductive material is specifically a conductive adhesive 83 in this embodiment, and the pressure processing component 30 is electrically connected to the external device by the conductive component 40 and the conductive adhesive 83.

Referring to fig. 5, a pressure sensor according to a second embodiment of the present invention is shown, in this embodiment, a portion of the conductive element 40 located outside the support 20 is connected to a conductive wire 72, a base 70 is fixed to the bottom of the substrate 10, a through hole 71 is formed in the base 70, and the through hole 71 connects the pressure sensitive membrane 60 to the outside.

Specifically, the pressure sensor in this embodiment is packaged together with the substrate 10 by the conductive element 40.

Referring to fig. 6, a pressure sensor according to a second embodiment of the present invention is shown, in this embodiment, a solder ball 80 is disposed outside the support 20 and clings to the conductive element 40. Specifically, the solder ball 80 abuts against the second conductive pad 43. The solder ball 80 is soldered to the circuit board 81.

Referring to fig. 7, a pressure sensor according to a fourth embodiment of the present invention is shown, in this embodiment, a solder ball 80 is disposed outside the support 20 and clings to the conductive element 40. Specifically, the solder ball 80 abuts against the second conductive pad 43. The solder ball 80 is soldered to the glass sealing conductive pillar 82.

The above-described embodiments describe the technical principles of the present invention, and these descriptions are only for the purpose of explaining the principles of the present invention, and should not be interpreted as limiting the scope of the present invention in any way. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without any inventive effort, which would fall within the scope of the present invention.

Claims

1. A pressure sensor, characterized by: the pressure sensor comprises a substrate, a support above the substrate, a pressure sensitive membrane for sensing pressure, and a pressure processing assembly for receiving and processing a pressure signal sensed by the pressure sensitive membrane, wherein a conductive assembly is arranged in the support, one end of the conductive assembly is connected with the pressure processing assembly, the other end of the conductive assembly extends to the outside of the support, the substrate is provided with an opening cavity, the opening direction of the opening cavity faces back to the extending direction of the conductive assembly, the pressure sensitive membrane is arranged in the opening cavity, a vacuum cavity is arranged in the pressure sensor, a piezoresistive membrane is arranged in the vacuum cavity and used for protecting the pressure processing assembly, and the pressure sensor passes through the conductive assembly or the conductive assembly and the substrate are packaged together.

2. The pressure sensor of claim 1, wherein: an insulating layer is arranged between the substrate and the support, the pressure processing assembly comprises a piezoresistor and an electrode connected with the piezoresistor, the electrode and the piezoresistor are fixed on the substrate, the orifice of the vacuum cavity faces the insulating layer, and the piezoresistor, the electrode and the insulating layer are attached.

3. The pressure sensor of claim 2, wherein: the conductive assembly comprises a conductive column, a first conductive gasket and a second conductive gasket, wherein the first conductive gasket and the second conductive gasket are respectively positioned at two ends of the conductive column, the first conductive gasket penetrates through the insulating layer and is connected with the electrode, the second conductive gasket is positioned at the outer side of the support, the pressure sensor is packaged through the second conductive gasket, and when the length and width of the pressure processing assembly is smaller than 1.6 multiplied by 1.6mm, the larger center distance between the two conductive gaskets is larger than 1.1 mm.

4. The pressure sensor of claim 3, wherein: the conductive column comprises a metal layer and a filling layer, a through hole is formed in the support, the metal layer is coated on the surface of the through hole, the filling layer is filled in the through hole, and the depth-to-width ratio of the through hole is larger than or equal to 3: 1.

5. The pressure sensor of claim 1, wherein: the shape of the opening cavity is trapezoidal or rectangular, and a round corner structure is arranged at the bottom of the opening cavity.

6. The pressure sensor of claim 1, wherein: one side of support is equipped with conducting material, electrically conductive subassembly passes through conducting material and external equipment electric connection, the support is fixed to through the mode of welding or adhesion on the external equipment.

7. The pressure sensor of claim 1, wherein: the part of the conductive component, which is positioned outside the support, is connected with a lead, a base is fixed at the bottom of the substrate, and a via hole is formed in the base and enables the pressure sensitive membrane to be communicated with the outside.

8. The pressure sensor of claim 1, wherein: and a solder ball clinging to the conductive assembly is arranged outside the support, and the solder ball is welded on the circuit board.

9. The pressure sensor of claim 1, wherein: and a solder ball tightly attached to the conductive assembly is arranged outside the support, and the solder ball is welded on the glass sealing conductive column.

10. The pressure sensor of claim 1, wherein: and the substrate is bonded with the support, and the surfaces of the substrate and the support are polished.