A MEMS packaging structure and manufacturing method thereof

Abstract

The present invention discloses a MEMS packaging structure and a manufacturing method thereof, belonging to the technical field of integrated circuit packaging. A pressure inlet channel (1‑1) is provided in the center of the pressure connector body, and a pressure dispersion port (1‑2) is provided at the outlet of the pressure inlet channel (1‑1). The pressure dispersion port (1‑2) includes a plurality of pairs of inverted Y-shaped dispersion ports. The pressure sensor chip (6) is adhered to the center of the base (4‑3) of the base (4) by an adhesive (7). The base (4) is fixedly connected to the adapter (2) upward, and a pressure sensitive diaphragm (3) is fixed between the base (4) and the adapter (2). The connector structure proposed by the present invention adopts a Y-shaped dispersion port to realize pressure diversion, and a pressure diversion channel is provided, which can effectively avoid the frontal impact of pressure on the MEMS chip.

Description

Technical Field

[0001] The invention relates to a MEMS packaging structure and a manufacturing method thereof, belonging to the technical field of integrated circuit packaging. Background Art

[0002] The fluid pressure sensor uses a pressure sensor chip based on silicon-based MEMS technology, called a MEMS pressure sensor chip. In the fluid pressure sensor, when the fluid pressure acts on the MEMS pressure sensor chip, the pressure-sensitive diaphragm is deformed, and the piezoresistors on the pressure-sensitive diaphragm change resistance due to the piezoresistance effect, which causes the Wheatstone bridge composed of piezoresistors in the pressure sensing element to generate an electrical signal output, realizing the conversion of pressure signals to electrical signals.

[0003] In the prior art, a fluid pressure sensor includes a sampling tube and a shell base connected to the sampling tube. A MEMS pressure sensor chip and a calibration chip are arranged in the shell base. The MEMS pressure sensor chip and the calibration chip are separately arranged in the shell base, so that a large space is occupied by the sensor, the material cost is high, the production cycle is long, and the stress generated by welding is large, which often causes product output drift. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a MEMS packaging structure with a pressure joint structure having an integrated pressure joint design and a manufacturing method thereof.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a MEMS packaging structure, which includes, from top to bottom, a pressure joint, a switching joint, a pressure sensitive diaphragm, a metal wire, a base, a metal pin and a pressure sensor chip.

[0007] The pressure joint comprises a pressure joint body and an interface, wherein a pressure inlet channel is provided at the center of the upper end of the pressure joint body and runs through the pressure joint body from top to bottom, and a pressure dispersion port is provided at the outlet of the pressure inlet channel, wherein the pressure dispersion port comprises a plurality of pairs of inverted Y-shaped dispersion ports, and the interface protrudes from the lower end side of the pressure joint body;

[0008] The adapter includes an adapter body, an adapter front interface, an adapter rear interface and a through hole I, wherein the through hole I is arranged at the center of the adapter body, the adapter front interface is arranged at the outer side of the upper end of the adapter body, and the adapter rear interface is arranged at the inner side of the lower end of the adapter body;

[0009] The base has a base in the center, and the outer edge of the base is provided with a plurality of terminals extending outward to form a MEMS pressure sensor detection cavity. A through hole II is provided at the middle end of the terminal, and a metal pin is passed through the through hole II. The upper end of the metal pin is fixedly connected to the terminal of the base through a glass sinter;

[0010] The pressure sensor chip is adhered to the center of the base of the base by adhesive, and the pressure sensor chip is electrically connected to the metal pin by a metal wire;

[0011] The terminals of the base and the edge of the pressure-sensitive membrane are aligned with the adapter rear interface of the adapter, the base is fixedly connected to the adapter upward, and the pressure-sensitive membrane is fixed between the base and the adapter;

[0012] The adapter front interface of the adapter is inserted into the interface of the pressure connector and fixedly connected.

[0013] Optionally, the pressure dispersion port is a pair of inverted Y-shaped dispersion ports.

[0014] Optionally, the pressure inlet channel is located directly above the through hole I.

[0015] Optionally, the pressure sensor chip is located directly below the through hole I.

[0016] Optionally, the lower end of the metal pin extends downward beyond the bottom of the base.

[0017] The present invention also provides a method for manufacturing a MEMS packaging structure, and the process is as follows:

[0018] Step 1: Take the raw material of the pressure joint body of appropriate size, use a lathe to process it into a symmetrical stepped shape, and leave enough size;

[0019] Step 2: Process the pressure distribution port of the pressure joint body. The specific steps are as follows:

[0020] Step 2.1, use a fixture to clamp the upper end of the pressure joint body horizontally, adjust the drill bit of the lathe horizontally to align with the axial symmetry center line of the pressure joint body, then make the pressure joint body deviate arbitrarily at an angle of α=45 degrees, feed the drill bit horizontally, stop at the axial symmetry center line of the pressure joint body, retract the drill, and form the first pressure dispersion port of the Y-shaped hole pointing obliquely upward to the center of the pressure joint body, and return the fixture to its original position;

[0021] Step 2.2, the pressure joint body is rotated circumferentially by an angle β, and step 2.1 is repeated to complete the second pressure dispersion port of the Y-shaped hole;

[0022] Step 2.3, repeat steps 2.1 and 2.2 to evenly complete all drillings;

[0023] Step 3: Replace the drill bit of the lathe with a milling cutter, and start from the axial symmetric center line of the pressure joint body and mill out the useless part of the interface at the lower end of the pressure joint body, and then close the cutter;

[0024] Step 4: Use a fixture to clamp the lower end of the pressure joint body, adjust the level, change the lathe to a larger drill bit, and use the lathe drill bit to horizontally cut along the axial symmetry center line of the pressure joint body, directly reach the depth of the pressure dispersion port, open all the pressure dispersion ports, form a pressure entry channel, and close the drill bit;

[0025] Step 5: Check and polish the entire pressure joint, remove burrs, and complete the manufacture of the pressure joint;

[0026] Step 6: Take an adapter, insert the front interface of the adapter into the interface of the pressure connector and connect them together by welding;

[0027] Step 7: Take a base, open a through hole II at the middle end of the terminal of the base, pass the metal pin through the through hole II, and use a glass sintering process to fix the upper end of the metal pin to the base through the glass sinter;

[0028] Step 8: Take a pressure sensor chip, and stick the pressure sensor chip to the center of the base of the base through adhesive, the pressure sensor chip is fixedly connected to one end of the metal wire through flux, and the other end of the metal wire is fixedly connected to the metal pin on the base through flux;

[0029] Step nine, align the terminals of the base, the edge of the pressure-sensitive membrane with the adapter rear interface of the adapter, fix the base upward with the adapter by welding, and fix the pressure-sensitive membrane between the base and the adapter.

[0030] Optionally, the angle β of the uniform circumferential rotation of the pressure joint body is calculated as follows:

[0031] If the dispersion port is a pair, the angle β rotates 180 degrees;

[0032] If there are two pairs of dispersion ports, the angle β rotates 90 degrees each time;

[0033] If there are three pairs of dispersion ports, the angle β rotates by 60 degrees each time; and so on.

[0034] Optionally, in step three, the cutting depth of the milling cutter is half the depth of the interface at the lower end of the joint body.

[0035] Optionally, in step six, the welding method is argon arc welding, laser welding or electron beam welding.

[0036] Optionally, in step nine, the welding method is argon arc welding, laser welding or electron beam welding.

[0037] Beneficial Effects

[0038] 1. The pressure joint in the MEMS package of the present invention adopts a Y-shaped pressure dispersion port, and the pressure entering the channel is diverted through the Y-shaped dispersion port, which can effectively avoid the frontal impact of the pressure on the MEMS chip. The pressure inlet connects the detected space and the pressure sensor chip, so that the MEMS chip (i.e., the pressure sensor chip) is in contact with the pressure source, which simplifies the structure, reduces the production cycle and cost, and reduces the material cost by about 50%;

[0039] 2. The pressure joint and the adapter, as well as the adapter and the base in the present invention are fixedly connected, which reduces one welding operation and avoids the negative impact of stress generated during the welding process on the pressure sensor chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A cross-sectional schematic diagram of a pressure joint structure for reducing welding according to the present invention;

[0041] Figure 2 for Figure 1 Usage status diagram;

[0042] FIG. 3A to FIG. 3I for Figure 1 A schematic diagram of a forming manufacturing method;

[0043] In the figure:

[0044] Pressure connector 1

[0045] Pressure inlet 1-1

[0046] Pressure dispersion port 1-2

[0047] Interface 1-3

[0048] Adapter 2

[0049] Adapter front interface 2-1

[0050] Adapter rear interface 2-2

[0051] Through hole Ⅰ2-3

[0052] Pressure sensitive diaphragm 3

[0053] Base 4

[0054] Glass sinter 4-1

[0055] Metal pin 4-2

[0056] Abutment 4-3

[0057] Through hole II 4-7

[0058] Metal Wire 5

[0059] Pressure sensor chip 6

[0060] Adhesive 7

[0061] Circuit board 8

[0062] Components on the circuit board 8-1

[0063] Connect through hole 8-2. DETAILED DESCRIPTION

[0064] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. For ease of description, spatial relative terms (such as "below", "beneath", "lower", "above", "upper", etc.) may be used to describe the relationship of one element or component to another element or component shown in the figures. In addition to the orientation shown in the figures, spatial relative terms also include different orientations of the device in use or operation. The device can be oriented in other ways, rotated 90 degrees or in other orientations, and the spatial relative descriptions used herein may be interpreted similarly accordingly.

[0065] like Figure 1 As shown, a MEMS packaging structure of the present invention includes, from top to bottom, a pressure joint 1, an adapter 2, a pressure sensitive diaphragm 3, a metal wire 5, a base 4, metal pins 4-5 and a pressure sensor chip 6.

[0066] The pressure connector 1 includes a pressure connector body and an interface 1-3. A pressure inlet channel 1-1 is provided at the center of the upper end of the pressure connector body, and a pressure dispersion port 1-2 is provided at the outlet of the pressure inlet channel 1-1. The pressure dispersion port 1-2 includes a plurality of pairs of inverted Y-shaped dispersion ports. A pair of inverted Y-shaped dispersion ports is shown in the figure, and two, three or four pairs may be provided, depending on actual needs, to disperse the instantaneous increased pressure entering from the channel 1-1, change the pressure flow direction, avoid the impact on the pressure sensor chip 6, and avoid deformation and damage to the chip. The interface 1-3 protrudes from the lower end side of the pressure connector body.

[0067] The adapter 2 includes an adapter body, an adapter front interface 2-1, an adapter rear interface 2-2, and a through hole I 2-3. The through hole I 2-3 is arranged in the center of the adapter body, directly below the pressure inlet channel 1-1. The adapter front interface 2-1 is arranged on the outer side of the upper end of the adapter body, and the adapter rear interface 2-2 is arranged on the inner side of the lower end of the adapter body.

[0068] The base 4 has a base 4-3 in the center, and a plurality of terminals 4-2 extending outward are provided on its side to form a MEMS pressure sensor detection cavity. A through hole II 4-7 is opened at the middle end of the terminal 4-2, and a metal pin 4-5 is passed through the through hole II 4-7. The upper end of the metal pin 4-5 is fixedly connected to the terminal 4-2 of the base 4 through a glass sinter 4-1.

[0069] The pressure sensor chip 6 is adhered to the center of the base 4-3 of the base 4 by adhesive 7, and is located directly below the pressure sensitive diaphragm 3. The pressure sensor chip 6 is electrically connected to the metal pin 4-5 by a metal wire 5, and the metal wire 5 enables the pressure chip 5 to communicate with the outside world, and is used for input voltage and signal output.

[0070] The terminal 4-2 of the base 4 and the edge of the pressure sensitive membrane 3 are aligned with the adapter rear interface 2-2 of the adapter 2, and the base 4 is welded upward with the adapter 2 by argon arc welding (or laser welding, electron beam welding), and the pressure sensitive membrane 3 is fixed between the base 4 and the adapter 2. The channel 1-1 of the pressure connector 1 and the pressure dispersion port 1-2 set at its outlet connect the pressure to the detected space and the test pressure sensor chip 6, so that the pressure sensor chip 6 contacts the pressure source, which simplifies the structure.

[0071] The adapter front interface 2 - 1 of the adapter 2 is inserted into the interface of the pressure connector 1 and is welded together and fixedly connected by argon arc welding (or laser welding, electron beam welding).

[0072] When in use, the lower end of the metal pin 4-5 of the base 4 is connected to the connecting through hole II 8-2 of the circuit board by soldering. The circuit board 8 is provided with components 8-1 such as capacitors and resistors for balancing the bridge circuit on the circuit board 8.

[0073] The present invention provides a method for manufacturing a MEMS packaging structure. FIG. 3A to FIG. 3I for Figure 1 The process diagram of the forming manufacturing method is as follows:

[0074] Step 1: Figure 3A As shown, take the raw material of the pressure joint body of appropriate size, use a lathe to process it into a symmetrical stepped shape, and leave enough size;

[0075] Step 2: Process the pressure distribution port 1-2 of the pressure connector body. The specific steps are as follows:

[0076] 1) Use a fixture to clamp the upper end of the pressure joint body horizontally, adjust the drill bit of the lathe horizontally to align with the axial symmetry center line of the pressure joint body, and then make the pressure joint body deviate arbitrarily at an angle of α=45 degrees. The drill bit is fed horizontally and stops at the axial symmetry center line of the pressure joint body. The drill is retracted to form the first pressure dispersion port 1-2 of the Y-shaped hole pointing obliquely upward to the center of the pressure joint body. The fixture is returned to its original position. Figure 3B As shown;

[0077] 2) The pressure joint body is rotated circumferentially by an angle β, and step 1) is repeated to complete the second pressure dispersion port 1-2 of the Y-shaped hole. Figure 3C As shown;

[0078] 3) Repeat steps 1) and 2) to complete all drilling;

[0079] In order to make the drilling holes evenly distributed, the angle β of the pressure joint body circumferential rotation is calculated as follows:

[0080] If the dispersion ports 1-2 are a pair, the angle β is rotated 180 degrees;

[0081] If there are two pairs of dispersion ports 1-2, the angle β rotates 90 degrees each time;

[0082] If there are three pairs of dispersion ports 1-2, the angle β rotates by 60 degrees each time; and so on.

[0083] Step 3: Replace the drill bit of the lathe with a milling cutter, and start from the axial symmetric center line of the pressure joint body to the outside, and mill off the useless part of the interface 1-3 at the lower end of the pressure joint body. The feed depth of the milling cutter is half of the depth of the interface 1-3 at the lower end of the joint body. Figure 3D As shown;

[0084] Step 4: Use a fixture to clamp the lower end of the pressure connector body, adjust the level, change the lathe to a larger drill bit, and let the drill bit of the lathe cut horizontally along the axial symmetry center line of the pressure connector body, directly reaching the depth of the pressure dispersion port 1-2, opening all the pressure dispersion ports 1-2, forming a pressure entry channel 1-1, and closing the drill bit. Figure 3E As shown;

[0085] Step 5: Check and polish the entire pressure joint 1 to remove burrs, and complete the manufacture of the pressure joint 1;

[0086] Step 6: Take an adapter 2, insert the adapter front interface 2-1 of the adapter 2 into the interface of the pressure connector 1 and use argon arc welding, laser welding or electron beam welding to fix them together, such as Figure 3F As shown;

[0087] Step 7: Take a base 4, open a through hole II 4-7 at the middle end of the terminal 4-2 of the base 4, pass the metal pin 4-5 through the through hole II 4-7, and fix the upper end of the metal pin 4-5 to the base 4 through the glass frit 4-1 through the glass sintering process, as shown in FIG. Figure 3G As shown;

[0088] Step 8: Take a pressure sensor chip 6, and stick the pressure sensor chip 6 to the center of the base 4-3 of the base 4 through the adhesive 7. The pressure sensor chip 6 is fixedly connected to one end of the metal wire 5 through the solder, and the other end of the metal wire 5 is fixedly connected to the metal pin 4-5 on the base 4 through the solder. Figure 3H As shown;

[0089] Step 9: Align the terminal 4-2 of the base 4 and the edge of the pressure sensitive membrane 3 with the adapter rear interface 2-2 of the adapter 2, and fix the base 4 upward to the adapter 2 by argon arc welding, laser welding or electron beam welding, and fix the pressure sensitive membrane 3 between the base 4 and the adapter 2. Fig. 3I The channel 1-1 of the pressure connector 1 and the pressure dispersion port 1-2 provided at its outlet connect the pressure to the detected space and the test pressure sensor chip 6, allowing the pressure sensor chip 6 to directly contact the pressure source, thus simplifying the structure.

[0090] The specific implementation methods described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A MEMS packaging structure, characterized in that: It comprises, from top to bottom, a pressure joint (1), an adapter (2), a pressure sensitive diaphragm (3), a metal wire (5), a base (4), a metal pin (4-5) and a pressure sensor chip (6); the pressure joint (1) comprises a pressure joint body and an interface (1-3); a pressure inlet channel (1-1) which passes through the pressure joint body from top to bottom is provided in the center of the upper end; a pressure dispersion port (1-2) is provided at the outlet of the pressure inlet channel (1-1); the pressure dispersion port (1-2) comprises a plurality of pairs of inverted Y-shaped dispersion ports; and the interface (1-3) protrudes from the lower end side of the pressure joint body; The adapter (2) comprises an adapter body, an adapter front interface (2-1), an adapter rear interface (2-2) and a through hole I (2-3), wherein the through hole I (2-3) is arranged at the center of the adapter body, the adapter front interface (2-1) is arranged at the outer side of the upper end of the adapter body, the adapter rear interface (2-2) is arranged at the inner side of the lower end of the adapter body, and the pressure inlet channel (1-1) is located directly above the through hole I (2-3); The base (4) has a base (4-3) in the center, and the outer edge of the base (4-3) is provided with a plurality of terminals (4-2) extending outward to form a MEMS pressure sensor detection cavity, and a through hole II (4-7) is provided at the middle end of the terminal (4-2), and the metal pin (4-5) passes through the through hole II (4-7), and the upper end of the metal pin (4-5) is fixedly connected to the terminal (4-2) of the base (4) through a glass sinter (4-1); The pressure sensor chip (6) is adhered to the center of the base (4-3) of the base (4) by means of an adhesive (7); the pressure sensor chip (6) is electrically connected to the metal pin (4-5) by means of a metal wire (5); and the pressure sensor chip (6) is located directly below the through hole I (2-3); The terminal (4-2) of the base (4) and the edge of the pressure-sensitive membrane (3) are aligned with the adapter rear interface (2-2) of the adapter (2), the base (4) is fixedly connected to the adapter (2) upward, and the pressure-sensitive membrane (3) is fixed between the base (4) and the adapter (2); The adapter front interface (2-1) of the adapter (2) is inserted into the interface (1-3) of the pressure connector (1) and is fixedly connected.

2. The MEMS packaging structure according to claim 1, characterized in that: The pressure dispersion ports (1-2) are a pair of inverted Y-shaped dispersion ports.

3. The MEMS packaging structure according to claim 1, characterized in that: The lower end of the metal pin (4-5) extends downward beyond the bottom of the base (4-3).

4. A method for manufacturing a MEMS packaging structure, the process of which is as follows: Step 1: Take the raw material of the pressure joint body of appropriate size, use a lathe to process it into a symmetrical stepped shape, and leave enough size; Step 2: Process the pressure distribution port (1-2) of the pressure connector body. The specific steps are as follows: Step 2.1, use a fixture to clamp the upper end of the pressure joint body horizontally, adjust the drill bit of the lathe horizontally to align with the axial symmetry center line of the pressure joint body, then make the pressure joint body deviate arbitrarily at an angle of α=45 degrees, feed the drill bit horizontally, stop at the axial symmetry center line of the pressure joint body, retract the drill, and form the first pressure dispersion port of the Y-shaped hole pointing obliquely upward to the center of the pressure joint body, and return the fixture to its original position; Step 2.2, the pressure joint body is rotated circumferentially by an angle β, and step 2.1 is repeated to complete the second pressure dispersion port of the Y-shaped hole; Step 2.3, repeat steps 2.1 and 2.2 to evenly complete all drillings; Step 3: Replace the drill bit of the lathe with a milling cutter, and start from the axial symmetry center line of the pressure connector body and mill off the useless part of the interface (1-3) at the lower end of the pressure connector body, and then put the cutter away; Step 4: Use a clamp to clamp the lower end of the pressure connector body, adjust the level, replace the lathe with a larger drill bit, and use the lathe drill bit to horizontally cut along the axial symmetry center line of the pressure connector body, directly reaching the deep end of the pressure dispersion port (1-2), opening all the pressure dispersion ports (1-2), forming a pressure inlet channel (1-1), and then close the drill bit; Step 5: Check and polish the entire pressure joint (1) to remove burrs, thereby completing the manufacture of the pressure joint (1); Step 6: Take an adapter (2), insert the adapter front interface (2-1) of the adapter (2) into the interface of the pressure connector (1) and fix them together by welding; Step 7, take a base (4), open a through hole II (4-7) at the middle end of the terminal (4-2) of the base (4), pass the metal pin (4-5) through the through hole II (4-7), and use a glass sintering process to fix the upper end of the metal pin (4-5) to the base (4) through the glass sinter (4-1); Step 8, take a pressure sensor chip (6), adhere the pressure sensor chip (6) to the center of the base (4-3) of the base (4) by means of adhesive (7), the pressure sensor chip (6) is fixedly connected to one end of the metal wire (5) by means of flux, and the other end of the metal wire (5) is fixedly connected to the metal pin (4-5) on the base (4) by means of flux; Step nine: align the terminal (4-2) of the base (4), the edge of the pressure-sensitive membrane (3) and the adapter rear interface (2-2) of the adapter (2), fix the base (4) upwards and the adapter (2) together by welding, and fix the pressure-sensitive membrane (3) between the base (4) and the adapter (2).

5. The manufacturing method according to claim 4, characterized in that: The angle β of the circumferential rotation of the pressure joint body is calculated as follows: If the dispersion ports (1-2) are a pair, the angle β is rotated 180 degrees; If there are two pairs of dispersion ports (1-2), the angle β rotates 90 degrees each time; If there are three pairs of dispersion ports (1-2), the angle β rotates by 60 degrees each time; and so on.

6. The manufacturing method according to claim 4, characterized in that: In step three, the cutting depth of the milling cutter is half the depth of the interface (1-3) at the lower end of the joint body.

7. The manufacturing method according to claim 4, characterized in that: In step six, the welding method is argon arc welding, laser welding or electron beam welding.

8. The manufacturing method according to claim 4, characterized in that: In step nine, the welding method is argon arc welding, laser welding or electron beam welding.

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