阅读说明：本技术 一种mems压力传感器充油芯体及其封装方法 (MEMS pressure sensor oil-filled core and packaging method thereof ) 是由 王小平 曹万 李凡亮 王红明 施涛 吴登峰 李兵 于 2020-06-11 设计创作，主要内容包括：本发明涉及压力传感器技术领域,且公开了一种MEMS压力传感器充油芯体,包括上盖、底座和敏感组件；所述上盖的下端与底座密封连接,所述底座和上盖构成密封腔体,所述密封腔体内填充有检测介质；所述底座上且位于密封腔体内设有敏感组件。该MEMS压力传感器充油芯体及其封装方法,采用硅弹性膜片和半导体电阻与信号标定模块组成的芯片,外部无需设置信号处理电路,引线互连少、结构简单、成本低、产品可靠性高,便于生产,并且半导体电阻和信号标定模块位于不同的平面,并且信号标定模块位于硅弹性膜片的四周,避免硅弹性膜片的应力变化影响到信号标定模块,导致信号标定模块中的线路受损的风险,有利于保证精度。(The invention relates to the technical field of pressure sensors and discloses an oil-filled core body of an MEMS (micro-electromechanical system) pressure sensor, which comprises an upper cover, a base and a sensitive component, wherein the upper cover is provided with a first oil-filled core body; the lower end of the upper cover is hermetically connected with the base, the base and the upper cover form a sealed cavity, and a detection medium is filled in the sealed cavity; and a sensitive component is arranged on the base and positioned in the sealed cavity. According to the MEMS pressure sensor oil-filled core body and the packaging method thereof, a chip consisting of the silicon elastic membrane, the semiconductor resistor and the signal calibration module is adopted, a signal processing circuit is not required to be arranged outside, the interconnection of leads is less, the structure is simple, the cost is low, the product reliability is high, the production is convenient, the semiconductor resistor and the signal calibration module are located on different planes, the signal calibration module is located around the silicon elastic membrane, the risk that the stress change of the silicon elastic membrane affects the signal calibration module to cause the damage of a circuit in the signal calibration module is avoided, and the precision is favorably ensured.)

1. The utility model provides a MEMS pressure sensor oil charge core which characterized in that: comprises an upper cover (10), a base (20) and a sensitive component (40);

the lower end of the upper cover (10) is hermetically connected with a base (20), the base (20) and the upper cover (10) form a sealed cavity (16), and a detection medium (17) is filled in the sealed cavity (16);

a sensitive component (40) is arranged on the base (20) and in the sealed cavity (16); the sensitive assembly (40) comprises a silicon elastic diaphragm (41) and a signal calibration module (42) which are positioned on the same plane;

the signal calibration module (42) is positioned around the silicon elastic membrane (41);

and a semiconductor resistor (43) is arranged on the silicon elastic membrane (41).

2. The MEMS pressure sensor oil filled core of claim 1, wherein: the upper surface (202) of the base (20) is provided with patch glue (302) and positioning marks (206), the patch glue (302) is used for adhering the sensitive component (40), and the positioning marks (206) are distributed on the periphery of the patch glue (302).

3. The MEMS pressure sensor oil filled core of claim 2, wherein: and a back pressing sheet (44) is also arranged between the patch adhesive (302) and the sensitive component (40).

4. The MEMS pressure sensor oil filled core of claim 2, wherein: the center of paster glue (302) is equipped with the round hole, the lower surface of base (20) is equipped with through-hole (510) with the round hole intercommunication.

5. The MEMS pressure sensor oil filled core of claim 1, wherein: still be equipped with pin (201) on base (20), be equipped with on pin (201) with sensitive subassembly (40) electrical connection's lead wire (301), the junction of pin (201) and base (20) is equipped with fritted glass (205).

6. The MEMS pressure sensor oil filled core of claim 1, wherein: the base (20) is further provided with a filling hole (204), and the lower surface of the base (20) is located in the filling hole (204) and connected with a steel ball (15).

7. The MEMS pressure sensor oil filled core of claim 1, wherein: and a first welding ring (203) with a conical section is arranged on the contact surface of the base (20) and the lower end of the upper cover (10) in sealing connection.

8. The MEMS pressure sensor oil filled core of claim 1, wherein: upper cover (10) include ring (11), pressure diaphragm (12) and shell (13), be equipped with second welding circle (14) on shell (13), shell (13) are connected through second welding circle (14) and ring (11), pressure diaphragm (12) are located between shell (13) and ring (11), pressure diaphragm (12) and shell (13) are the metal of same model.

9. The MEMS pressure sensor oil filled core of claim 8, wherein: the upper surface (202) of the shell (13) is provided with a pressure-resistant blocking groove (131), and the lower surface of the shell (13) is provided with a medium groove (132); the dielectric groove (132) is communicated with the overpressure blocking groove (131).

10. A packaging method for an oil filling core of an MEMS pressure sensor comprises the following steps:

(a) the circular ring (11), the pressure diaphragm (12) and the shell (13) are coaxially combined in sequence, and the upper cover (10) is formed in a sealing welding mode through a second welding ring (14);

(b) bonding the sensitive component (40) on the patch adhesive (302) of the base (20), and positioning through the positioning mark (206) to realize rapid patch;

(c) carrying out ultrasonic thermal bonding on the sensitive component (40) and the pins (201) through leads (301) to form electrical connection;

(d) the base (20) and the upper cover (10) are hermetically welded in a resistance welding mode through a first welding ring (203) with a conical section;

(e) pouring liquid medium into a medium groove (132) in the shell (13) through the filling hole (204) in a vacuum environment;

(f) the steel ball (15) is hermetically welded with a filling hole (204) on the base (20) to form an oil-filled core body;

(g) and carrying out calibration test on the completed oil-filled core body.

Technical Field

The invention relates to the technical field of pressure sensors, in particular to an oil-filled core body of an MEMS pressure sensor and a packaging method thereof.

Background

The pressure sensor mainly has the function of converting an external pressure signal into an electric signal, and is widely applied to the fields of automotive electronics, aerospace, petrochemical industry, medical appliances, consumer electronics and the like.

The pressure chip is used as a core device of the pressure sensor and mainly can be divided into pressure sensors of diffused silicon piezoresistive type, capacitive type, piezoelectric type, resonant type and the like; the pressure-sensitive element is manufactured in the pressure-sensitive membrane area by an ion implantation mode; in addition, the MEMS pressure sensor has small volume, light weight, low cost, high sensitivity, wide application environment and different requirements on the packaging modes of the MEMS pressure sensor by different application environments, and the oil-filled cores of the pressure sensors with different packaging modes are published for meeting the medium compatibility of the sensors; the prior oil-filled core packaging mode is difficult to get rid of the defects of high product cost, complex manufacturing process, low precision, poor reliability and the like, and the patent CN106768592A discloses 'a pressure transmitter oil-filled core with a signal processing function', wherein a base is a high-pressure sintering seat, the base body is machined and manufactured, the machining efficiency is low, the cost is high, the manufacturing process cannot be compatible with the mature semiconductor packaging process, such as automatic high-speed paster and full-automatic high-speed lead bonding, in addition, the temperature measurement module, the signal processing unit and the pressure sensing unit are arranged on the same working surface, and because the pressure sensing unit belongs to the weakest region of a sensor chip and continuously deforms along with the pressure change, the signal processing unit is also arranged on the working surface, the internal microcircuit faces the risk of fatigue damage; in the medium isolation type pressure sensor packaging structure disclosed by the patent CN1056343A, a pressure sensor packaging module is arranged in an oil filling cavity, the packaging module cannot ensure that no gas remains in the sealed cavity due to the moisture absorption of the material and the existence of air holes, and meanwhile, the output temperature drift of the pressure sensor is increased due to the excessive filling volume of the internal silicone oil, so that the precision of the sensor is reduced; patent CN208721309U has announced "a simple and easy oil-filled core", paste the direct riveting of tube shell that has the pressure chip, and this process leads to the huge stress of tube shell product, and stress transfer to pressure chip to cause sensor output drift, uniformity and precision degrade, in addition, the inside sealing washer that is provided with the thermal expansion coefficient far surpasses the silicon chip of seal chamber, causes the output temperature drift of sensor increase sensor under high low temperature condition.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides an oil-filled core body of an MEMS pressure sensor and a packaging method thereof, which have the advantages of high detection precision of the oil-filled core body and the like, and solve the problem that in the prior art, a temperature measurement module, a signal processing unit and a pressure sensing unit are arranged on the same working surface, and because the pressure sensing unit belongs to the weakest area of a sensor chip and continuously deforms along with pressure change, the signal processing unit is also arranged on the surface, so that a microcircuit in the chip is exposed to the risk of fatigue damage, and the precision of the sensor is reduced.

(II) technical scheme

In order to realize the purpose of high detection precision of the oil-filled core body, the invention provides the following technical scheme: an oil-filled core body of an MEMS pressure sensor comprises an upper cover, a base and a sensitive component;

the lower end of the upper cover is hermetically connected with the base, the base and the upper cover form a sealed cavity, and a detection medium is filled in the sealed cavity;

a sensitive component is arranged on the base and positioned in the sealed cavity; the sensitive assembly comprises a silicon elastic membrane and a signal calibration module which are positioned on the same plane;

the signal calibration module is positioned around the silicon elastic membrane;

and the silicon elastic membrane is provided with a semiconductor resistor.

Preferably, the upper surface of the base is provided with a patch adhesive and positioning marks, the patch adhesive is used for adhering the sensitive components, and the positioning marks are distributed on the periphery of the patch adhesive.

Preferably, a back pressing sheet is further arranged between the patch glue and the sensitive component.

Preferably, the center that the paster was glued is equipped with the round hole, the lower surface of base is equipped with the through-hole with the round hole intercommunication.

Preferably, the base is further provided with a pin, the pin is provided with a lead electrically connected with the sensitive component, and the joint of the pin and the base is provided with sintered glass.

Preferably, the base is further provided with a filling hole, and the lower surface of the base is located in the filling hole and connected with a steel ball.

Preferably, a first welding ring with a conical section is arranged on a contact surface of the base and the lower end of the upper cover in sealing connection.

Preferably, the upper cover includes ring, pressure diaphragm and shell, be equipped with the second welding circle on the shell, the shell passes through the second welding circle and the ring is connected, the pressure diaphragm is located between shell and the ring, pressure diaphragm and shell are the metal of same model.

Preferably, the upper surface of the shell is provided with a pressure-resistant blocking groove, and the lower surface of the shell is provided with a medium groove; the medium groove is communicated with the overpressure blocking groove.

A packaging method for an oil filling core of an MEMS pressure sensor comprises the following steps:

(a) the circular ring, the pressure diaphragm and the shell are coaxially combined in sequence, and the upper cover is formed in a sealing welding mode through a second welding ring;

(b) bonding the sensitive assembly on the adhesive tape of the base, and positioning through the positioning mark to realize rapid adhesive tape pasting;

(c) carrying out ultrasonic thermal bonding on the sensitive assembly and the pin through a lead to form electrical connection;

(d) the base and the upper cover are hermetically welded in a resistance welding mode through a first welding ring with a conical section;

(e) pouring liquid medium into the medium groove in the shell through the filler hole under the vacuum environment;

(f) sealing and welding the steel balls with the filling holes on the base to form an oil-filled core body;

(g) and carrying out calibration test on the completed oil-filled core body.

(III) advantageous effects

Compared with the prior art, the invention provides an oil-filled core body of an MEMS pressure sensor and a packaging method thereof, and the oil-filled core body has the following beneficial effects:

1. according to the MEMS pressure sensor oil-filled core body and the packaging method thereof, a chip consisting of the silicon elastic membrane, the semiconductor resistor and the signal calibration module is adopted, a signal processing circuit is not required to be arranged outside, the interconnection of leads is less, the structure is simple, the cost is low, the product reliability is high, the production is convenient, the semiconductor resistor and the signal calibration module are located on different planes, the signal calibration module is located around the silicon elastic membrane, the risk that the stress change of the silicon elastic membrane affects the signal calibration module to cause the damage of a circuit in the signal calibration module is avoided, and the precision is favorably ensured.

2. According to the MEMS pressure sensor oil filling core and the packaging method thereof, the circular ring, the pressure diaphragm and the shell are made of metal of the same type, and are packaged by adopting all metal, so that materials with strong hygroscopicity and large thermal expansion coefficient, such as a PCB (printed Circuit Board) and plastic parts, are not arranged in the sealed cavity, and bubbles, moisture and thermal deformation generated in the sealed cavity are avoided, so that the reliability and the precision of a product are reduced.

3. According to the MEMS pressure sensor oil-filled core and the packaging method thereof, the medium filling amount in the sealed cavity is controlled to be the minimum volume, the smaller the medium filling volume is, the smaller the contraction and expansion amount of a product caused by the CTE of a medium material is correspondingly under the high and low temperature change, and the improvement of the high and low temperature precision of the MEMS pressure sensor oil-filled core is facilitated.

4. According to the oil-filled core body of the MEMS pressure sensor and the packaging method thereof, the surface-mounted adhesive and the positioning marks are arranged on the upper surface of the base, the surface-mounted adhesive is used for adhering sensitive components, and the positioning marks are distributed on the periphery of the surface-mounted adhesive for positioning, so that high-speed automatic surface mounting is realized conveniently.

Drawings

Fig. 1 is a cross-sectional view of a first embodiment of an oil filled core structure of a MEMS pressure sensor according to the present invention.

Fig. 2 is a structural diagram of an upper cover in a first embodiment of an oil core of a MEMS pressure sensor according to the present invention.

Fig. 3 is a structural diagram of a base and a sensitive component in a first embodiment of an oil core of a MEMS pressure sensor according to the present invention.

Fig. 4 is a structural diagram of a sensitive component in a first embodiment of an oil core of a MEMS pressure sensor according to the present invention.

Fig. 5 is a top view of a base in a first embodiment of an oil filled core of a MEMS pressure sensor according to the present invention.

Fig. 6 is a cross-sectional view of a second embodiment of an oil filled core of a MEMS pressure sensor according to the present invention.

Fig. 7 is a structural diagram of a sensitive component in a second embodiment of the oil core of the MEMS pressure sensor according to the present invention.

In the figure: 10 upper cover, 20 base, 201 pin, 202 base upper surface, 203 first welding ring, 204 filling hole, 205 sintered glass, 206 positioning mark, 301 lead, 302 patch glue, 40 sensitive component, 41 silicon elastic diaphragm, 42 signal calibration module, 43 semiconductor resistor, 44 backpressure sheet, 510 through hole, 11 ring, 12 pressure diaphragm, 13 shell, 131 overpressure blocking groove, 132 medium groove, 14 second welding ring, 15 steel ball, 16 sealing cavity, 17 detection medium.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.