WO2015014179A1

WO2015014179A1 - Capacitive mems acceleration sensor

Info

Publication number: WO2015014179A1
Application number: PCT/CN2014/080645
Authority: WO
Inventors: 陈学峰; 钟利强; 杨小平
Original assignee: 苏州固锝电子股份有限公司
Priority date: 2013-07-30
Filing date: 2014-06-24
Publication date: 2015-02-05
Also published as: CN103412146B; CN104880572A; CN104880573B; CN104880573A; CN104880572B; CN103412146A

Abstract

A capacitive MEMS acceleration sensor comprising an MEMS acceleration chip (1), a signal processing chip (2) and a substrate (3). The MEMS acceleration chip (1) comprises a cover body (4), a micromechanical system (5) and a circuit substrate (6), the micromechanical system (5) is composed of an X-axis acceleration induction area (7), a Y-axis acceleration induction area (8) and a Z-axis acceleration induction area (9); the Y-axis acceleration induction area (8) comprises a Y-direction 'H'-shaped moving sheet (81) with two through holes, two Y-direction moving electrodes (82) and two Y-direction fixed electrodes (83); the Z-axis acceleration induction area (9) comprises a mass block (24) and a supporting shaft (25) for supporting the center of the mass block (24); the lower surface of the circuit substrate (6) is bonded with a partial area on the upper surface of the signal processing chip (2) through a first insulation adhesive layer (12); the upper surface of the circuit substrate (6) is provided with a plurality of chip welding points (14), the upper surface of the substrate (3) is provided with a plurality of substrate welding points (15) which are distributed in the edge areas on the two sides of the substrate (3), and the upper surface of the signal processing chip (2) is provided with signal input welding points (16) and signal output welding points (17) respectively. The capacitive MEMS acceleration sensor improves the reliability of a device and effectively reduces stress damage to the chips by an external force.

Description

Capacitive MEMS accelerometer

Technical field

[0001] The present invention relates to the field of acceleration sensor technologies, and in particular, to a capacitive MEMS acceleration sensor. Background technique

[0002] MEMS accelerometers have attracted much attention due to their small size, light weight, low cost, and high reliability, especially in the aerospace and weapon science fields where the size, quality and reliability of devices are very high. Great application prospects. The research of accelerometers has developed rapidly in recent years, and various range and range of high-range accelerometers have been reported. However, the acceleration sensor has high requirements for high overload capability and natural frequency. Generally, the anti-high overload capability can withstand hundreds of thousands of range impact loads, and the natural frequency requirements are up to tens of kHz or even hundreds of kHz. Therefore, in applications, MEMS high-range accelerometers often suffer from structural failure due to poor resistance to high overload. In order to ensure the reliability of MEMS high-range accelerometers in application, the packaging of MEMS high-range accelerometers is particularly important. Practice shows that the existing sensor packaging technology generally suffers from the problem of poor high overload resistance, low natural frequency, and poor package reliability, that is, the MEMS high-range acceleration sensor packaged by the existing sensor packaging technology encounters a harsh application environment. Problems such as cracking of the shell, depression of the cover, peeling of the chip from the shell substrate, and breakage of the lead often occur. Based on this, it is necessary to invent a capacitive MEMS accelerometer to ensure the reliability of the acceleration sensor in application.

Summary of the invention

[0003] It is an object of the present invention to provide a capacitive MEMS accelerometer that improves the reliability of the device and effectively reduces stress damage to the chip by external forces.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: A capacitive MEMS acceleration sensor, comprising a MEMS acceleration chip, a signal processing chip and a substrate for filtering an interference signal and processing the sensing signal, the MEMS acceleration chip The micro-mechanical system is composed of a cover body, a micro-mechanical system and a circuit substrate for generating an induced signal, and the micro-mechanical system is composed of an X-axis acceleration sensing region, a Y-axis acceleration sensing region, and a Z-axis acceleration sensing region for sensing an external Z-axis motion. The cover body and the peripheral edge of the circuit substrate are bonded by a sealant layer to form a sealed cavity. The micromechanical system is located in the sealed cavity and on the upper surface of the circuit substrate, and the height of the sealed cavity is 45~55 μm _;

The X-axis acceleration sensing region includes an X-direction "Η"-shaped moving piece having two through holes, two X-direction moving electrodes, and two X-direction fixed electrodes, and the first spring and the second spring are respectively mounted to the X side. To the left and right ends of the "Η" shaped moving piece, the other ends of the first spring and the second spring are respectively mounted on the circuit substrate, and the two X-direction moving electrodes are respectively located in the X-direction "Η"-shaped moving piece 2 through holes and movable together with the X-direction "Η"-shaped moving piece, the X-direction fixed electrode and the X-direction moving electrode are disposed face to face and directly below the X-direction moving electrode;

The cymbal acceleration sensing region includes a Η""" moving piece having two through holes, two slanting moving electrodes, and two slanting fixed electrodes, and the third spring and the fourth spring are respectively mounted to the Υ The other ends of the upper and lower ends of the "Η" shaped moving piece are respectively mounted on the circuit substrate, and the two moving moving electrodes are respectively located in the through holes of the "Η" shaped moving piece And movable along with the "Η"-shaped moving piece, the facing fixed electrode and the moving moving electrode are disposed face to face and directly below the moving moving electrode; The shape moving piece, the third spring and the fourth spring are arranged in a direction perpendicular to the X-direction moving electrode, the first spring and the second spring in the X-axis acceleration sensing area; the ζ-axis acceleration sensing area includes the mass bar and the a support shaft for supporting a center of the mass bar, wherein the two ends of the mass strip are respectively provided with a 感应-axis sensing electrode, and the limit bar is respectively disposed above the two ends of the mass bar;

The lower surface of the circuit substrate is bonded to the upper surface portion of the signal processing chip through the first insulating adhesive layer, and the lower surface of the signal processing chip is bonded to the substrate partial region through the second insulating adhesive layer, the circuit substrate and the substrate Each of the upper surfaces respectively has a plurality of chip soldering points and a plurality of substrate soldering points on both sides of the distributed substrate. The upper surface of the signal processing chip has a plurality of signal input soldering points and signal output soldering points respectively, and the signal output soldering points are respectively outputted. Located in the second insulating adhesive layer and distributed in the edge regions of the signal processing chip, the first metal wire is connected between the solder joint of the chip and the signal input soldering point, and the second metal wire is distributed across the two sides. Between the signal output solder joint and the substrate solder joint.

[0005] The solution of the above technical solution is further improved as follows: 1. In the above solution, the upper and lower ends of the X-direction "H"-shaped motion piece are respectively provided with a first bump, and the first bump is located between the two first limiting portions of the circuit substrate.

[0006] 2. In the above solution, the Y-direction "H"-shaped motion piece is provided with a second bump on the upper and lower ends, and the second bump is located between the two second limit portions of the circuit substrate. .

[0007] 3. In the above solution, the height of the sealed cavity is 50 μm.

[0008] 4. In the above solution, the X-axis acceleration sensing area and the Υ-axis acceleration sensing area are located in a row, and the 加-axis acceleration sensing area is disposed in parallel with the X-axis acceleration sensing area and the Υ-axis acceleration sensing area.

[0009] 5. In the above solution, the substrate solder joint opens the upper surface of the circuit substrate and is located on the side of the cover.

[0010] 6. In the above solution, the through hole is square.

[0011] Due to the above technical solutions, the present invention has the following advantages and effects compared with the prior art:

1. The capacitive MEMS accelerometer of the present invention, the lower surface of the circuit substrate is bonded to the upper surface portion of the signal processing chip through the first insulating adhesive layer, and the lower surface of the signal processing chip passes through the second insulating adhesive layer and the substrate portion The surface bonding, the upper surface of the circuit substrate and the substrate respectively have a plurality of chip soldering points and a plurality of substrate soldering points on both side edges of the distributed substrate, and the signal processing chip has a plurality of signal input soldering points and signals respectively on the upper surface of the signal processing chip Outputting a soldering point, the signal output soldering point is located in the second insulating adhesive layer and distributed on both edge regions of the signal processing chip, and the first metal line is connected between the solder joint of the chip and the signal input soldering point, and is distributed The second metal wires on both sides are connected between the signal output soldering point and the substrate soldering point, and the package reliability is high. The welding of the insulating rubber layer effectively reduces the stress damage of the external force on the chip, and the position layout of the soldering point is designed. It is possible to perform wire bonding in a very small package space. The first is to make the wire of the wire shorter and the cost is lower. Gel threading technology to solve high level of diversity is not stable arc wire line problems and improve the feasibility of mass production.

[0012] 2. The capacitive MEMS accelerometer of the present invention has a first bump on the upper and lower ends of the X-direction "H"-shaped moving piece, and the first bump is located at two first limits of the circuit substrate. Between the parts, the Y-direction "H"-shaped moving piece is provided with a second bump at the upper and lower ends, and the second protrusion is located between the two second limiting portions of the circuit substrate, thereby effectively preventing production Under the action of acceleration, the internal structure damage of the X-axis and Y-axis acceleration sensing areas is avoided.

[0013] 3. The capacitive MEMS acceleration sensor of the present invention, the Z-axis acceleration sensing region includes a mass strip and a support shaft for supporting the center of the mass strip, and the Z-axis sensing electrode is disposed directly below both ends of the mass strip A limit stop is arranged directly above the two ends of the mass bar, which can effectively protect the mechanical damage of the internal structure, and at the same time greatly improve the sensitivity of the induction.

[0014] 4. The capacitive MEMS acceleration sensor of the present invention has an X-axis acceleration sensing area and a Y-axis acceleration sensing area in a row, and the z-axis acceleration sensing area is arranged in parallel with the X-axis acceleration sensing area and the Y-axis acceleration sensing area. Effectively reducing the position of the sensing area in the chip circuit, which is more advantageous in terms of cost and package feasibility. Secondly, the substrate soldering point opens the upper surface of the circuit substrate and is located on the side of the cover body, which is beneficial to the chip arrangement and Reduce the difficulty of cutting and threading during the packaging process.

DRAWINGS

1 is a schematic structural view of a capacitive MEMS acceleration sensor according to the present invention;

Figure 2 is a schematic left side view of Figure 1;

Figure 3 is a bottom plan view of Figure 1;

4 is a schematic structural view of a MEMS acceleration chip according to the present invention;

Figure 5 is a schematic structural view of a micromechanical system of the present invention;

6 is a schematic structural view of an X-axis acceleration sensing area in an acceleration sensor according to the present invention;

7 is a partial structural schematic view of an X-axis acceleration sensing area of the present invention;

8 is a schematic structural view of a Y-axis acceleration sensing area in an acceleration sensor according to the present invention;

9 is a schematic structural view of a Z-axis acceleration sensing area in an acceleration sensor according to the present invention;

Figure 10 is a bottom plan view of Figure 9;

In the above drawings: 1. MEMS acceleration chip; 2. Signal processing chip; 3. Substrate; 4. Cover; 5. Micro-mechanical system; 6. Circuit substrate; 7. X-axis acceleration sensing area; "H" shaped moving piece; 72, X-direction moving electrode; 73, X-direction fixed electrode; 74, first spring; 75, second spring; 8, Y-axis acceleration sensing area; 81, Y-direction "H"-shaped moving piece; 82, Y-direction moving electrode; 83, Y-direction fixed 84; third spring; 85, fourth spring; 9, Z-axis acceleration sensing area; 10, sealant layer; 11, sealing cavity; 12, first insulating adhesive layer; 13, second insulating adhesive layer 14, chip solder joints; 15, substrate solder joints; 16, signal input solder joints; 17, signal output solder joints; 18, the first metal line; 19, the second metal line; 20, the first bump; The first limiting portion; 22, the second convex portion; 23, the second limiting portion; 24, the mass bar; 25, the supporting shaft; 26, the Z-axis sensing electrode; 27, the limiting block.

detailed description

[0016] The present invention will be further described below in conjunction with the embodiments:

Embodiments: A capacitive MEMS acceleration sensor comprising a MEMS acceleration chip 1, a signal processing chip 2 for filtering an interference signal and processing an induced signal, and a substrate 3, the MEMS acceleration chip 1 being covered by a cover 4, a micromechanical system 5 And a circuit substrate 6 for generating an inductive signal, the micromechanical system 5 being composed of an X-axis acceleration sensing region 7, a Y-axis acceleration sensing region 8, and a Z-axis acceleration sensing region 9 for sensing an external Z-axis motion, The cover 4 and the peripheral edge of the circuit substrate 6 are bonded by a sealant layer 10 to form a sealed cavity 11. The micromechanical system 5 is located in the sealed cavity 11 and on the upper surface of the circuit substrate 6, the height of the sealed cavity 11. 45~55 μ ιη _;

The X-axis acceleration sensing region 7 includes an X-direction "Η"-shaped moving piece 71 having two through holes, two X-direction moving electrodes 72, and two X-direction fixed electrodes 73, a first spring 74 and a second spring 75. The respective ends are respectively mounted to the left and right ends of the X-direction "Η"-shaped moving piece 71, and the other ends of the first spring 74 and the second spring 75 are respectively mounted on the circuit substrate 6, and the two X-direction moving electrodes are respectively mounted. 72 are respectively located in the two through holes of the X-direction "Η"-shaped moving piece 71 and are movable along with the X-direction "Η"-shaped moving piece 71, and the X-direction fixed electrode 73 and the X-direction moving electrode 72 are disposed face to face. And it is directly below the X-direction moving electrode 72;

The cymbal acceleration sensing region 8 includes a Η"" shaped moving piece 81 having two through holes, two slanting moving electrodes 82, and two slanting fixed electrodes 83, a third spring 84 and a fourth spring 85. One end of each of the third spring 84 and the fourth spring 85 is respectively mounted on the circuit substrate 6, and the other end is respectively mounted on the upper and lower ends of the "Η"-shaped moving piece 81, The two Y-direction moving electrodes 82 are respectively located in the through holes of the "Η"-shaped moving piece 81 and can move with the "Η"-shaped moving piece 81, and move toward the fixed electrode 83 and the tilting movement. The electrodes 82 are disposed face to face and are directly below the moving moving electrode 82; the direction of the "Η" shaped moving piece 81, the third spring 84 and the fourth spring 85 in the x-axis acceleration sensing area 8 and the X-axis acceleration The X-direction moving electrode 72, the first spring 74 and the second spring 75 in the sensing area 7 are arranged in a vertical direction; the Ζ-axis acceleration sensing area 9 includes a mass bar 24 and a support shaft 25 for supporting the center of the mass bar 24, The first end of the mass bar 24 is provided with a cymbal sensing electrode 26, and a limit stop 27 is disposed above the two ends of the mass bar 24;

The lower surface of the circuit substrate 6 is bonded to the upper surface portion of the signal processing chip 2 through the first insulating adhesive layer 12, and the lower surface of the signal processing chip 2 is bonded to the partial region of the substrate 3 through the second insulating adhesive layer 13. The upper surface of the circuit substrate 6 and the substrate 3 respectively have a plurality of chip soldering points 14 and a plurality of substrate soldering points 15 on both side edges of the distributed substrate 3. The signal processing chip 2 has a plurality of signal input soldering on the upper surface thereof. Point 16 and signal output solder joint 17, the signal output solder joint 17 is located in the second insulating adhesive layer 13 and distributed on both edge regions of the signal processing chip 2, and the first metal line 18 is connected across the chip solder joint 14 Between the signal input pads 16 and the second metal lines 19 distributed on both sides are bridged between the signal output pads 17 and the substrate pads 15.

[0017] The upper and lower ends of the X-direction "Η"-shaped moving piece 71 are respectively provided with a first bump 20, and the first bump 20 is located between the two first limiting portions 21 of the circuit substrate 6.

[0018] The upper and lower ends of the "Η"-shaped moving piece 81 are provided with second bumps 22, and the second bumps 22 are located between the two second limiting portions 23 of the circuit substrate 6.

[0019] The above sealed chamber 11 has a height of 50 μm.

[0020] The X-axis acceleration sensing area 7 and the Y-axis acceleration sensing area 8 are located in a row, and the Z-axis acceleration sensing area

9 is set in parallel with the X-axis acceleration sensing zone 7 and the Y-axis acceleration sensing zone 8.

[0021] The substrate soldering point 15 is formed on the upper surface of the circuit substrate 6 and on the side of the cover 4; the through hole is square.

[0022] The above embodiments are only for explaining the technical idea and features of the present invention, and the purpose thereof is to enable those skilled in the art. The contents of the present invention can be understood and implemented, and the scope of the present invention is not limited thereby. Equivalent variations or modifications made in accordance with the spirit of the invention are intended to be included within the scope of the invention.

Claims

Claim

A capacitive MEMS acceleration sensor, comprising: a MEMS acceleration chip (1), a signal processing chip (2) for filtering an interference signal and processing an induced signal, and a substrate (3), the MEMS acceleration chip ( 1) by the cover body (4), the micromechanical system (5) and the circuit substrate (6) for generating an induced signal, the micromechanical system (5) is induced by the X-axis acceleration sensing region (7), Y-axis acceleration The region (8) is composed of a Z-axis acceleration sensing region (9) for sensing the external Z-axis motion, and the cover body (4) is bonded to the peripheral edge of the circuit substrate (6) through the sealant layer (10) to form a sealed chamber (11), the micromechanical system (5) located in the seal chamber (11) and the upper surface of the circuit substrate (6), the height of the sealing chamber (11) is 45 ~ _55μιη;

The X-axis acceleration sensing region (7) includes an X-direction "Η" shaped moving piece (71) having two through holes, two X-direction moving electrodes (72), and two X-direction fixed electrodes (73), One end of each of a spring (74) and a second spring (75) is respectively mounted to the left and right ends of the X-direction "Η"-shaped moving piece (71), and the other ends of the first spring (74) and the second spring (75) are respectively Mounted on the circuit substrate (6), two of the X-direction moving electrodes (72) are respectively located in two through holes of the X-direction "Η"-shaped moving piece (71) and can follow the X-direction "Η" a "moving motion piece (71) - a movement, the X-direction fixed electrode (73) being disposed face-to-face with the X-direction moving electrode (72) and being directly below the X-direction moving electrode (72);

The cymbal acceleration sensing region (8) includes a Η"" shaped moving piece (81) having two through holes, two slanting moving electrodes (82), and two slanting fixed electrodes (83), One end of each of the three springs (84) and the fourth spring (85) is respectively mounted on the upper and lower ends of the "Η"-shaped moving piece (81), and the other ends of the third spring (84) and the fourth spring (85) are respectively mounted. On the circuit substrate (6), two of the moving moving electrodes (82) are respectively located in the through holes of the "Η" shaped moving piece (81) and can move with the "Η" shape. a piece (81)-moving, the slanting fixed electrode (83) is disposed face-to-face with the slanting moving electrode (82) and is directly below the slanting moving electrode (82); the yaw axis acceleration sensing area (8) The direction of the "Η" shaped moving piece (81), the third spring (84) and the fourth spring (85) and the X-direction moving electrode (72) in the X-axis acceleration sensing area (7), the first spring (74) ) is perpendicular to the arrangement direction of the second spring (75); the yoke acceleration sensing region (9) includes a mass bar (24) and a support mass bar (2) 4) a support shaft (25) of the center, a shaft sensing electrode (26) is disposed directly below the two ends of the mass bar (24), and a limit stop is arranged directly above the two ends of the mass bar (24) 27);

The lower surface of the circuit substrate (6) is bonded to the upper surface portion of the signal processing chip (2) through the first insulating adhesive layer (12), and the lower surface of the signal processing chip (2) passes through the second insulating adhesive layer. (13) bonding to a partial region of the substrate (3), the upper surface of each of the circuit substrate (6) and the substrate (3) is respectively provided with a plurality of chip soldering points (14) and a plurality of distributed substrates (3) The substrate soldering point (15), the signal processing chip (2) has a plurality of signal input soldering points (16) and a signal output soldering point (17) on the upper surface, and the signal output soldering point (17) is located in the second insulating layer The adhesive layer (13) is disposed on both side edge regions of the signal processing chip (2), and the first metal wire (18) is bridged between the chip soldering point (14) and the signal input soldering point (16). A second metal line (19) distributed on both sides is bridged between the signal output pad (17) and the substrate pad (15).

The capacitive MEMS accelerometer according to claim 1, wherein: the X-direction "H"-shaped moving piece (71) is provided with a first protrusion (20) at the upper and lower ends, the first protrusion The block (20) is located between the two first limiting portions (21) of the circuit substrate (6).

The capacitive MEMS accelerometer according to claim 1, wherein: the Y-direction "H"-shaped moving piece (81) is provided with a second bump (22) at the upper and lower ends, the second convex The block (22) is located between the two second limiting portions (23) of the circuit substrate (6).

The capacitive MEMS accelerometer according to claim 1, wherein the sealing chamber (11) has a height of 50 μm.

The capacitive MEMS acceleration sensor according to claim 1, wherein: the X-axis acceleration sensing area (7) and the Y-axis acceleration sensing area (8) are located in a row, and the Z-axis acceleration sensing area ( 9) Set in parallel with the X-axis acceleration sensing area (7) and the Y-axis acceleration sensing area (8).

The capacitive MEMS accelerometer according to claim 1, characterized in that the substrate soldering point (15) is provided on the upper surface of the circuit substrate (6) and on the side of the cover (4).

7. The capacitive MEMS accelerometer according to claim 1, wherein: the through hole is square.