CN210243053U - Pressure sensor core body based on flip chip and pressure sensor - Google Patents
Pressure sensor core body based on flip chip and pressure sensor Download PDFInfo
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- CN210243053U CN210243053U CN201921052241.5U CN201921052241U CN210243053U CN 210243053 U CN210243053 U CN 210243053U CN 201921052241 U CN201921052241 U CN 201921052241U CN 210243053 U CN210243053 U CN 210243053U
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Abstract
The utility model discloses a pressure sensor core and pressure sensor based on flip-chip bonding chip, the core includes: a rigid housing having a through hole therein; one end of the terminal is in flip-chip welding with the MEMS pressure sensitive chip through a welding flux, and the other end of the terminal is connected with a circuit board of the sensor after penetrating through the through hole on the rigid shell so as to realize signal processing; the isolation medium is filled in the through hole of the rigid shell and used for sealing and fixedly connecting the part of the terminal, which is positioned in the through hole, with the inner wall of the through hole; the epoxy filler is filled among the MEMS pressure sensitive chip, the terminal and the solidified isolation medium and the periphery of the MEMS pressure sensitive chip, the terminal and the solidified isolation medium and is used for protecting the solder joint; when the MEMS pressure sensitive chip works, the pressure of a measured medium acts on the MEMS pressure sensitive chip, and signal change caused by the pressure is output through the terminal.
Description
Technical Field
The utility model relates to a pressure sensor makes the field, specifically is a pressure sensor core and pressure sensor based on flip-chip bonding chip.
Background
The pressure sensor generally comprises a pressure sensing element and a signal processing unit, senses a pressure signal through the pressure sensing unit, converts the pressure signal into an available output electric signal according to a certain rule, and processes the electric signal into required analog output or digital output through the signal processing unit. The sensor has complex use environment including complex medium environment such as water, oil, various liquids, gas, refrigerant and the like.
The pressure sensitive unit of the common pressure sensor comprises the following technologies: ceramic capacitors, ceramic resistors, glass micro-melting, sputtered thin films, micro-electro-mechanical systems (MEMS). The ceramic capacitor/ceramic resistor can only be sealed by adopting an O-shaped ring, cannot be compatible with various pressure media, has the risk of failure and leakage for a long time under certain media (such as refrigerants), and has large packaging volume. The glass micro-melting is used for sintering the sensing chip on the diaphragm by glass, the process is complex, and the equipment investment is large. The sputtering film sputters the pressure induction module on the base, so the equipment investment is large, the cost is high, and the sputtering film is not popularized.
MEMS pressure sensors based on MEMS can be mass produced with high precision and low cost in a similar integrated circuit technology. However, the packaging technology and process severely limit the application range of the MEMS pressure sensor. At present, the common technology based on the MEMS pressure sensor comprises the modes of back glue chip sticking, eutectic welding and oil filling. The back adhesive chip is connected with the pressure chip through adhesive, and then the gold wire or the aluminum wire is used for realizing electric connection, so that the back adhesive chip cannot be used for pressure measurement of complex media, and the chip has the risk of falling off from the adhesive under pressure and cannot bear large pressure. The eutectic welding mode seals the pressure chip on the metal tube shell by eutectic welding and then realizes electric connection through a gold wire or an aluminum wire, so that the material cost (chip/welding flux/kovar and the like) is high, the eutectic welding mode and the laser welding mode are used for resistance welding, and the process is complex.
The oil-filled core body encapsulates the MEMS pressure sensing chip in a closed structure filled with silicone oil, external pressure is transmitted to the pressure sensor chip from the stainless steel diaphragm through the silicone oil, and the oil-filled core body can realize good isolation of media, but the process is complex, the cost of the product is very high, and the volume is large.
Flip chip technology is an advanced packaging technology that directly interconnects a die to a substrate. In the packaging process, the bonding points on the chip are connected to the bonding points on the substrate through the metal conductors in a face-down manner, as shown in fig. 2. The flip chip bonding has many excellent packaging characteristics such as short interconnection, small area, three-dimensional channel, high mounting density and the like, can realize miniaturized packaging, and has been widely applied to the semiconductor industry.
In the field of pressure sensors, flip chip bonding of pressure chips has not been widely used due to limitations in packaging technology. The main packaging form is flip chip bonding of the chip on a PCB or a ceramic substrate. The PCB or the ceramic substrate is sealed in a mode of gluing or compressing an O-shaped ring.
The main defects of flip chip bonding on the PCB are as follows: the expansion coefficients of the PCB and the chip are greatly different, the welding spot has the risk of cracking failure caused by stress in the application field with large temperature difference change, the precision drift is caused by the action of the stress on the MEMS chip, the tolerance of the PCB medium is limited, and the PCB medium can not be applied to liquid or corrosive gas. The PCB and the shell are bonded by glue, and the risk of glue falling due to back pressure is easily caused.
The ceramic substrate is adopted, signals of the pressure chip can be led out from the back face only by adopting a double-sided board or other complicated modes, the circuit of the pressure sensing face needs to be coated and protected, and the substrate and the shell can only adopt a mode of gluing or sealing an O-shaped ring. Gluing also has the disadvantage of a small adaptation range of the medium. The O-shaped ring cannot be sealed in a small size, and cannot be realized in an application environment with a small size requirement. The O-shaped ring seal also has leakage risk in the application fields of refrigerants and the like.
SUMMERY OF THE UTILITY MODEL
To the technical problem, the utility model provides a simple process's pressure sensor core, this sensor core can lead to signal processing unit one side with pressure sensing signal from pressure sensing one side in minimum space, can use in the multiple medium including the refrigerant. The pressure core body is small in size, and different packaging forms can be realized according to different applications. The core body structure is simple in process and easy to realize large-scale production.
In order to realize the technical purpose, the utility model adopts the following technical scheme:
a flip chip based pressure sensor core comprising:
a rigid housing having a through hole therein;
one end of the terminal is in flip-chip welding with the MEMS pressure sensitive chip through a welding flux, and the other end of the terminal is connected with a circuit board of the sensor after penetrating through the through hole on the rigid shell so as to realize signal processing;
the isolation medium is filled in the through hole of the rigid shell and used for sealing and fixedly connecting the part of the terminal, which is positioned in the through hole, with the inner wall of the through hole;
the epoxy filler is filled among the MEMS pressure sensitive chip, the terminal and the solidified isolation medium and the periphery of the MEMS pressure sensitive chip, the terminal and the solidified isolation medium and is used for protecting the solder joint;
when the MEMS pressure sensitive chip works, the pressure of a measured medium acts on the MEMS pressure sensitive chip, and signal change caused by the pressure is output through the terminal.
The rigid shell is made of kovar or stainless steel.
The isolation medium is glass.
The epoxy filler is an epoxy resin having a high Tg.
A pressure sensor adopts the pressure sensor core body based on the flip chip.
Has the advantages that:
the utility model relates to a pressure sensor core compares current pressure sensor core and has following advantage based on flip-chip bonding chip:
1. the utility model discloses pressure sensor core simple structure based on flip-chip bonding chip, spare part is few, can standardize automatic batch production.
2. The pressure signal can be connected to one side of the circuit processing through the terminal in a small volume, and the core body structure is small, so that different forms of packaging can be realized.
3. The core terminals are packaged by the isolation medium, so that the position degree between the terminals is kept, the influence of stress on the MEMS pressure chip is greatly reduced, and the reliability and the precision can be ensured.
4. The core body has good adaptability to various media, can be applied to various media such as refrigerants and the like, can be designed in a fully-sealed mode, and solves the problem of medium compatibility of the MEMS pressure chip.
Drawings
Fig. 1 is a schematic structural diagram of a pressure sensor core body based on a flip chip of the present invention;
1, an MEMS pressure sensitive chip; 2. welding flux; 3. an epoxy filler; 4. a rigid housing; 5. an isolation medium; 6. and a terminal.
Fig. 2 is a schematic structural diagram of a pressure sensor core package type 1 based on a flip chip according to the present invention;
wherein, 4, the core body; 5. a sensor housing; 6. welding the part by laser;
fig. 3 is a schematic structural diagram of a pressure sensor core package type 2 (a) based on a flip chip according to the present invention;
wherein 7, the O-shaped ring is sealed;
fig. 4 is a schematic structural diagram of a flip chip based pressure sensor core package type 2 (b) of the present invention;
8, a connector assembly;
fig. 5 is a schematic structural diagram of a pressure sensor core package type 3 based on a flip chip according to the present invention;
wherein, 9, adhesive glue.
Detailed Description
The technical solution of the present invention will be further described in detail with reference to the drawings and specific embodiments of the present invention.
As shown in fig. 1, the utility model adopts the following technical scheme:
a flip chip based pressure sensor core comprising:
a rigid shell 4, wherein the rigid shell 4 is provided with a through hole;
one end of the terminal 6 is in flip-chip welding with the MEMS pressure sensitive chip 1 through the welding flux 2, and the other end of the terminal 6 is connected with a circuit board of the sensor after penetrating through the through hole on the rigid shell 4 so as to realize signal processing;
the isolating medium 5 is filled in the through hole of the rigid shell 4 and is used for sealing and fixedly connecting the part of the terminal 6 in the through hole and the inner wall of the through hole;
the epoxy filler 3 is filled among the MEMS pressure sensitive chip, the terminal and the solidified isolation medium and the periphery of the MEMS pressure sensitive chip, the terminal and the solidified isolation medium and is used for protecting the solder joint;
when the MEMS pressure sensitive chip works, the pressure of a measured medium acts on the MEMS pressure sensitive chip, and signal change caused by the pressure is output through the terminal.
As a preferred embodiment of the present invention, the material of the rigid casing is kovar or stainless steel. The coefficient of expansion of kovar or stainless steel is relatively low.
As a preferred embodiment of the present invention, the isolation medium is glass. The glass has small thermal expansion coefficient, can endure the application fields of refrigerants with rapid temperature change and the like, and has good medium compatibility with oil and various gases.
As a preferred embodiment of the present invention, the epoxy filler is an epoxy resin having a high Tg. The high-Tg epoxy filler 3 is filled between the flip chip 1 and the glass 5 and at the periphery of the flip chip to protect a welding joint, the stress of the high-Tg epoxy on a welding spot and the chip is small, the welding spot can be prevented from cracking in a large temperature range, the chip cannot generate precision drift due to the stress, and the filler can bear various media such as refrigerant oil and the like.
Manufacturing approach of pressure sensor core based on flip-chip bonding chip, the utility model discloses the key technical essential of scheme:
1. the applicability of the core body to media such as refrigerants and the like;
2. the flatness of the head part of the terminal is in a controllable range so as to ensure the flip chip bonding effect of the chip;
3. the influence of stress on the chip under the condition of temperature change is minimized;
4. the chip is required to be accurately positioned with the terminal when being pasted;
5. the solder joints need to be protected from the medium.
The method comprises the following steps:
s1, fixing the terminal in the through hole of the rigid shell through an isolation medium, and enabling the other end of the terminal to penetrate out of the through hole of the rigid shell; the terminal is sealed by high-temperature glass (FS 139, Elan48 and other air conditioner compressor wiring terminal sealing glass) and Kovar alloy or stainless steel rigid body, and the glass and Kovar or stainless steel have low thermal expansion coefficient and do not generate stress cracking when the temperature is changed violently. The glass body has excellent air tightness, low thermal expansion coefficient and high temperature resistance, the air tightness can reach 10^ -9pa.cm & lt 3 & gt/sec, the working temperature can reach 180 ℃, and the glass body can be applied to measurement environments with high sealing requirements and large temperature change (-40 ℃ to 150 ℃) such as compressor refrigerants and the like. And glass has good compatibility with most media,
s2, welding the MEMS pressure sensitive chip with one end of the terminal through solder to realize the electrical connection of the MEMS pressure sensitive chip and the terminal, and connecting the other end of the terminal with a circuit board of the sensor to realize signal processing; and sealing the terminal in the through hole of the rigid shell through glass, wherein the other end of the terminal penetrates out of the through hole of the rigid shell, and after the glass and the terminal are sintered, the head of the terminal is pressed or ground to ensure the flatness of the four terminals.
The linear expansion coefficient of the glass is 4.6ppm (3 ppm) close to that of silicon, the low glass expansion coefficient ensures that the relative positions of the 4 terminals and the welding points of the chip are unchanged under the environment of frequent temperature change, and the output accuracy of the chip cannot be greatly influenced by tensile stress to generate large drift. The chip is accurately attached to the 4 terminals by positioning the terminals through an image system with the positioning precision +/-0.05 mm.
And S3, filling epoxy filler with high Tg among the MEMS pressure sensitive chip, the terminal and the solidified isolation medium and at the periphery of the MEMS pressure sensitive chip, the terminal and the solidified isolation medium to protect the welding nodes. The heating system of the dispenser heats the core body to 60 ℃, epoxy is scribed from the side surface of the chip and dispensed, the epoxy has extremely low viscosity in a heating state, the epoxy is sucked into the bottom through capillary phenomenon, and high-temperature curing is carried out after dispensing is finished. The epoxy forms a protection against liquid or gas attack to the weld spot. The high Tg epoxy reduces stress mismatch between the chip and the epoxy filler, and does not cause large tensile stress to the chip to cause precision drift.
The packaging type of the pressure sensor core body based on the flip chip comprises the following three types:
the first method comprises the following steps: as shown in fig. 2, the metal sensor housing is sealed by laser welding, and for the weldable metal sensor housing, the metal sensor housing and the rigid housing are sealed by laser welding to realize complete sealing; can be applied to the fields of refrigerants and the like with strict requirements on leakage.
And the second method comprises the following steps: an O-ring seal, as shown in fig. 3, is provided between the outer wall of the rigid housing of the core body and the inner wall of the sensor housing, and assists the connector or other components to apply a certain pressure to the upper part of the core body under the application condition of a large pressure so as to prevent the core body from falling off;
or an O-shaped ring seal is arranged at the bottom of the rigid shell of the core body, as shown in figure 4, the pressure core body is fixed after the connector or other parts are riveted by the shell body at the upper part, and the seal is formed by the compression of the O-shaped ring; the packaging volume is small, and the packaging process is simple.
And the third is that: and (3) gluing and sealing, as shown in fig. 5, wherein the side surface or the bottom surface of the outer wall of the rigid shell of the core body is connected with the inner wall of the sensor shell in a sealing way by using adhesive glue. The packaging process is simple and easy to control, does not need expensive equipment investment, and is suitable for some gas application fields.
A pressure sensor adopts the pressure sensor core body based on the flip chip.
Claims (5)
1. A pressure sensor core based on a flip chip, comprising:
a rigid housing having a through hole therein;
one end of the terminal is in flip-chip welding with the MEMS pressure sensitive chip through a welding flux, and the other end of the terminal is connected with a circuit board of the sensor after penetrating through the through hole on the rigid shell so as to realize signal processing;
the isolation medium is filled in the through hole of the rigid shell and used for sealing and fixedly connecting the part of the terminal, which is positioned in the through hole, with the inner wall of the through hole;
the epoxy filler is filled among the MEMS pressure sensitive chip, the terminal and the solidified isolation medium and the periphery of the MEMS pressure sensitive chip, the terminal and the solidified isolation medium and is used for protecting the solder joint;
when the MEMS pressure sensitive chip works, the pressure of a measured medium acts on the MEMS pressure sensitive chip, and signal change caused by the pressure is output through the terminal.
2. The flip chip based pressure sensor core of claim 1 wherein the rigid housing material is kovar or stainless steel.
3. The flip chip based pressure sensor core of claim 1 wherein said isolation medium is glass.
4. The flip chip based pressure sensor core of claim 1 wherein the epoxy filler is an epoxy resin having a high Tg.
5. A pressure sensor, characterized in that a flip chip based pressure sensor core according to any of claims 1 to 4 is used.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921052241.5U CN210243053U (en) | 2019-07-08 | 2019-07-08 | Pressure sensor core body based on flip chip and pressure sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921052241.5U CN210243053U (en) | 2019-07-08 | 2019-07-08 | Pressure sensor core body based on flip chip and pressure sensor |
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| CN210243053U true CN210243053U (en) | 2020-04-03 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110207885A (en) * | 2019-07-08 | 2019-09-06 | 南京新力感电子科技有限公司 | Pressure sensor core, core manufacture and packaging method and pressure sensor based on upside-down mounting welding core |
| CN111397668A (en) * | 2020-06-03 | 2020-07-10 | 南京新力感电子科技有限公司 | Sensor core, core manufacturing and packaging method and sensor |
-
2019
- 2019-07-08 CN CN201921052241.5U patent/CN210243053U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110207885A (en) * | 2019-07-08 | 2019-09-06 | 南京新力感电子科技有限公司 | Pressure sensor core, core manufacture and packaging method and pressure sensor based on upside-down mounting welding core |
| WO2021004165A1 (en) * | 2019-07-08 | 2021-01-14 | 南京新力感电子科技有限公司 | Flip chip-based pressure sensor core, core manufacturing and packaging method, and pressure sensor |
| CN111397668A (en) * | 2020-06-03 | 2020-07-10 | 南京新力感电子科技有限公司 | Sensor core, core manufacturing and packaging method and sensor |
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