Novel MEMS pressure sensor chip

Abstract

The utility model relates to a novel MEMS pressure sensor chip. The novel MEMS pressure sensor chip comprises a chip main body, a pressure diaphragm, a bonding layer and four bonding pads, the four bonding pads are all arranged at the bottom of the pressure sensor chip, the chip body is connected with the bonding pads, the bonding layer is arranged between the pressure diaphragm and the chip body in an attached mode, and the pressure diaphragm is arranged in a hole-free mode and located at the top of the novel MEMS pressure sensor chip. A vacuum cavity is formed in the top of the chip main body; the pressure diaphragm comprises a main board body, a light doping piezoresistor and a heavy doping circuit, and the light doping piezoresistor and the heavy doping circuit form a Wheatstone detection bridge. According to the novel MEMS pressure sensor chip, a bonding wire is not needed for circuit connection, the pressure diaphragm and the chip main body are bonded through the bonding layer, connection is simplified, the pressure diaphragm is arranged in a hole-free mode, abnormal diaphragm pressure sensing caused by impurity blockage is avoided, wire binding and oil filling are not needed, the structure is simple, the size is small, and the cost is low.

Description

Technical Field

[0001] The utility model belongs to the technical field of pressure chips, and particularly relates to a novel MEMS pressure sensor chip. Background Art

[0002] A MEMS pressure sensor is a pressure sensor manufactured based on micro-electro-mechanical system (MEMS) technology, and has characteristics such as being tiny, high-precision, low-power consumption, and high reliability. A MEMS pressure sensor usually consists of a micro-electro-mechanical system chip, a pressure sensor chip, a signal processing circuit, etc., and can convert a pressure signal into an electrical signal for output. However, conventional MEMS pressure sensor chips require wire bonding, oil filling, and diaphragm to transmit pressure, and the product size is relatively large and the cost is relatively high.

[0003] Therefore, aiming at the problems of relatively large product size and relatively high cost in the prior art, a novel MEMS pressure sensor chip needs to be provided. Summary of the Utility Model

[0004] The utility model provides a novel MEMS pressure sensor chip, which solves the problems that conventional MEMS pressure sensor chips require wire bonding, oil filling, and diaphragm to transmit pressure, and the product size is relatively large and the cost is relatively high.

[0005] The utility model is realized through the following technical solutions: it includes a chip body, a pressure diaphragm, a bonding layer, and four pads; the four pads are all arranged at the bottom of the pressure sensor chip, the chip body is connected to the pads, the bonding layer is adhesively arranged between the pressure diaphragm and the chip body, the pressure diaphragm is non-porous and is located at the top of the novel MEMS pressure sensor chip; a vacuum cavity is arranged at the top of the chip body; the pressure diaphragm includes a main board body, lightly doped piezoresistors, and heavily doped circuits, and the lightly doped piezoresistors and the heavily doped circuits form a Wheatstone detection bridge.

[0006] In order to better realize the utility model, further optimization is made to the above structure, and each of the pads includes a base and a connecting rod, and the connecting rod is vertically arranged on the base.

[0007] In order to better realize the utility model, further optimization is made to the above structure, the chip body is a cuboid, the vacuum cavity is a square groove, and first through holes are arranged at the four corner positions of the chip body.

[0008] In order to better realize the utility model, further optimization is made to the above structure, second through holes are arranged at the four corners of the bonding layer, the positions of the first through holes and the second through holes are opposite and communicated, and the connecting rods of the four pads respectively pass through the first through holes and the second through holes in sequence and then are connected to the pressure diaphragm.

[0009] To better implement the present utility model, further optimization is made to the above structure. The lightly doped piezoresistor includes a first resistor, a second resistor, a third resistor, and a fourth resistor.

[0010] To better implement the present utility model, further optimization is made to the above structure. The heavily doped circuit includes a first circuit, a second circuit, a third circuit, and a fourth circuit.

[0011] To better implement the present utility model, further optimization is made to the above structure. The lightly doped piezoresistor and the heavily doped circuit are arranged at the bottom of the main board body; the heavily doped circuit is in contact electrical connection with four pads.

[0012] To better implement the present utility model, further optimization is made to the above structure. The first resistor and the second resistor are connected in series on the first circuit, the third resistor and the fourth resistor are connected in series on the second circuit, and the first circuit and the second circuit are connected in parallel on the third circuit and the fourth circuit.

[0013] To better implement the present utility model, further optimization is made to the above structure. The bonding layer is a square plate and has the same size as the top surface area of the chip body, and a square hollow is provided in the middle of the bonding layer.

[0014] To better implement the present utility model, further optimization is made to the above structure. The connecting rod passes through the first through hole of the chip body and the second through hole of the bonding layer and is then electrically connected to the heavily doped circuit, and the bottom of the chip body is attached to the surface of the base.

[0015] The present utility model has the following beneficial effects compared with the prior art: This new type of MEMS pressure sensor chip does not require wire bonding for circuit connection. The pressure diaphragm is bonded to the chip body through the bonding layer, simplifying the connection, eliminating the need for wire tying and oil filling. It has a simple structure, small size, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 is the front view of the new type of MEMS pressure sensor chip in the present utility model;

[0018] Figure 2 is the front view of the pressure diaphragm in the present utility model.

[0019] In the figure:

[0020] 1 - Chip body; 2 - Pressure diaphragm; 3 - Bonding layer; 4 - Pad; 5 - Main board body; 6 - Lightly doped piezoresistor; 7 - Heavily doped circuit; 8 - Base; 9 - Connecting rod; 10 - First through hole; 11 - Second through hole; 61 - First resistor; 62 - Second resistor; 63 - Third resistor; 64 - Fourth resistor; 71 - First circuit; 72 - Second circuit; 73 - Third circuit; 74 - Fourth circuit. Detailed implementation manner

[0021] To make the objectives, technical solutions and advantages of the present utility model clearer, the technical solutions of the present utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other implementation manners obtained by those of ordinary skill in the art without creative efforts shall fall within the scope protected by the present utility model.

[0022] In the description of the present utility model, it should be noted that unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present utility model. In addition, terms such as "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0023] In the description of the present utility model, it should also be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0024] Embodiment 1:

[0025] A novel MEMS pressure sensor chip, such as Figure 1 、 2As shown in the figure, it includes a chip body 1, a pressure diaphragm 2, a bonding layer 3, and four pads 4. The four pads 4 are all arranged at the bottom of the pressure sensor chip. The chip body 1 is connected to the pads 4. The bonding layer 3 is adhesively disposed between the pressure diaphragm 2 and the chip body 1, so that the pressure diaphragm 2 is bonded to the chip body 1 through the bonding layer 3. The pressure diaphragm 2 is non-porous and is located at the top of the novel MEMS pressure sensor chip. A vacuum cavity is provided at the top of the chip body 1. Therefore, the pressure diaphragm 2 is located at the top of the pressure sensor chip to serve as a pressure-bearing component.

[0026] With this structure, the novel MEMS pressure sensor chip does not require wire bonding for circuit connection. The pressure diaphragm 2 and the chip body 1 are bonded through the bonding layer 3, which simplifies the connection. The main board body 5 is a circuit board. The pressure diaphragm 2 is non-porous, avoiding abnormal pressure sensing of the diaphragm caused by impurity blockage. There is no need for wire tying or oil filling. The structure is simple, the size is small, and the cost is low.

[0027] It should be noted that the principle of the MEMS pressure sensor chip in the present utility model is that after the pressure diaphragm 2 bears an external pressure, four strain resistors that are respectively in tension and compression are generated, forming a Wheatstone detection bridge, becoming a pressure sensing module that integrates stress sensitivity and force-electricity conversion detection. Under the action of pressure, two resistors in the Wheatstone bridge become larger and two resistors become smaller, and a voltage signal is output. The voltage signal is conditioned by the ASIC circuit and then a voltage signal linearly related to the pressure signal is output.

[0028] The four pads 4 have the same structure and each includes a base 8 and a connecting rod 9. The connecting rod 9 is vertically arranged on the base 8. The chip body 1 is a cuboid. A square groove is provided on the chip body 1. First through holes 10 are provided at the four corner positions of the chip body 1. Similarly, second through holes 11 are provided at the four corners of the bonding layer 3. The first through holes 10 and the second through holes 11 are opposite in position and communicate with each other. The connecting rods 9 of the four pads 4 respectively pass through the first through holes 10 and the second through holes 11 in sequence and then are connected to the pressure diaphragm 2.

[0029] The pressure diaphragm 2 includes a main board body 5, lightly doped piezoresistors 6, and heavily doped circuits 7. The main board body 5 is a silicon substrate. The lightly doped piezoresistors 6 and the heavily doped circuits 7 are both arranged on the main board body 5. The lightly doped piezoresistors 6 and the heavily doped circuits 7 are ion-implanted at the bottom of the main board. The lightly doped piezoresistors 6 and the heavily doped circuits 7 are electrically connected to form a Wheatstone detection bridge. The square groove cooperates with the main board to form a vacuum cavity.

[0030] The lightly doped piezoresistor 6 includes a first resistor 61, a second resistor 62, a third resistor 63, and a fourth resistor 64; the heavily doped circuit 7 includes a first circuit 71, a second circuit 72, a third circuit 73, and a fourth circuit 74. The lightly doped piezoresistor 6 and the heavily doped circuit 7 are disposed at the bottom of the main board body. The heavily doped circuit 7 is in contact electrical connection with four pads 4. The four pads 4 are connected to an external circuit to form a path. The first resistor 61 and the second resistor 62 are connected in series on the first circuit 71, the third resistor 63 and the fourth resistor 64 are connected in series on the second circuit 72, and the first circuit 71 and the second circuit 72 are connected in parallel on the third circuit 73 and the fourth circuit 74. Further, the first resistor and the third resistor can be used as power supply resistors, and the second resistor and the fourth resistor can output signals; or the first resistor and the third resistor can output signals, and the second resistor and the fourth resistor can be used as power supply resistors.

[0031] The bonding layer 3 is a square plate and has the same size as the top surface area of the chip body 1. A square hollow is provided in the middle, and the square hollow is slightly smaller than the square groove of the chip body 1.

[0032] Further, the connecting rod 9 passes through the first through hole 10 of the chip body 1 and the second through hole 11 of the bonding layer 3 and is electrically connected to the heavily doped circuit 7. The bottom of the chip body 1 is attached to the surface of the base 8, so that the chip body 1 and the pressure diaphragm 2 are electrically connected through the pads 4.

[0033] The above is only the specific implementation manner of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of changes or substitutions, which should all be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope of the claimed rights.

Claims

1. A novel MEMS pressure sensor chip, characterized in that: The invention comprises a chip body (1), a pressure diaphragm (2), a bonding layer (3) and four pads (4); the four pads (4) are all arranged at the bottom of the pressure sensor chip, the chip body (1) is connected to the pads (4), the bonding layer (3) is laminated between the pressure diaphragm (2) and the chip body (1), the pressure diaphragm (2) is non-porous and is located on the top of the novel MEMS pressure sensor chip; a vacuum cavity is provided on the top of the chip body (1); the pressure diaphragm (2) comprises a main body (5), a lightly doped piezoresistance (6) and a heavily doped circuit (7), the lightly doped piezoresistance (6) and the heavily doped circuit (7) forming a Wheatstone detection bridge electrically connected to the pads (4).

2. A novel MEMS pressure sensor chip according to claim 1, characterized in that: The welding pads (4) each comprise a base (8) and a connecting rod (9), and the connecting rod (9) is vertically arranged on the base (8).

3. A novel MEMS pressure sensor chip according to claim 2, characterized in that: The chip body (1) is a rectangular parallelepiped, the vacuum chamber is a square groove, and first through holes (10) are provided at the four corners of the chip body (1).

4. A novel MEMS pressure sensor chip according to claim 3, characterized in that: The bonding layer (3) is provided with a second through hole (11) at each of its four corners, the first through hole (10) and the second through hole (11) are located opposite to and communicate with each other, and the connecting rods (9) of the four pads (4) respectively pass through the first through hole (10) and the second through hole (11) in sequence and are connected to the pressure diaphragm (2).

5. A novel MEMS pressure sensor chip according to any one of claims 1 to 4, characterized in that: The lightly doped piezoresistor (6) comprises a first resistor (61), a second resistor (62), a third resistor (63) and a fourth resistor (64).

6. The novel MEMS pressure sensor chip according to claim 5 is characterized in that: The heavy-doping circuit (7) comprises a first circuit (71), a second circuit (72), a third circuit (73) and a fourth circuit (74).

7. The novel MEMS pressure sensor chip according to claim 6 is characterized in that: The lightly doped piezoresistors (6) and heavily doped circuits (7) are arranged at the bottom of the main board body (5); the heavily doped circuits (7) are electrically connected to the four pads (4) in a contact manner.

8. The novel MEMS pressure sensor chip according to claim 7 is characterized in that: The first resistor (61) and the second resistor (62) are connected in series to the first circuit (71), the third resistor (63) and the fourth resistor (64) are connected in series to the second circuit (72), and the first circuit (71) and the second circuit (72) are connected in parallel to the third circuit (73) and the fourth circuit (74).

9. The novel MEMS pressure sensor chip according to claim 7, characterized in that: The bonding layer (3) is a square plate and has a size that is consistent with the area of ​​the top surface of the chip body (1). A square hollow is provided in the middle of the bonding layer (3).

10. The novel MEMS pressure sensor chip according to claim 4, characterized in that: The connecting rod (9) passes through the first through hole (10) of the chip body (1) and the second through hole (11) of the bonding layer (3) and is electrically connected to the heavy-doping circuit (7), and the bottom of the chip body (1) is in contact with the surface of the base (8).

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