Through type and differential pressure type combined dual-redundancy pressure sensor and preparation method thereof

Abstract

The invention discloses a through type and differential pressure combined dual-redundancy pressure sensor and a preparation method thereof, the sensor comprises a differential pressure type pressure-sensitive chip and a through type pressure-sensitive chip which are sequentially stacked from bottom to top, and a bonding layer is arranged between the differential pressure type pressure-sensitive chip and the through type pressure-sensitive chip. The preparation method comprises the following steps: preparing the differential pressure type pressure-sensitive chip and the through type pressure-sensitive chip, and respectively bonding the differential pressure type pressure-sensitive chip and the through type pressure-sensitive chip with the bonding layer to form a sandwich structure to finish preparation. The sensor can realize dual-redundancy measurement of a single pressure point under the cooperative use of the through-type pressure-sensitive chip and the differential pressure-type pressure-sensitive chip, has the advantages of high sensitivity, quick response, good stability and the like, is a novel pressure sensor with excellent performance and convenience in use, and can reduce the number and the size of the pressure sensor by the preparation method, so that the production cost is reduced. The method has the advantages of being simple in process, convenient to operate, low in cost, high in yield and the like, is suitable for large-scale preparation, and facilitates industrial application.

Description

Technical Field

[0001] The invention belongs to the technical field of thin film sensors and relates to a dual-redundancy pressure sensor combining a through-type and a differential pressure type and a preparation method thereof. Background Art

[0002] Pressure sensor is an important physical quantity acquisition sensor. The accuracy and stability of its information are of great significance to system performance and safety. At present, a single pressure sensor is often used to collect pressure information. However, when the pressure sensor collects information errors, the system cannot quickly determine whether it is a system failure or a pressure sensor failure. To solve the above problems, a direct and effective measure is to increase the pressure sensor to form a redundant design. However, in the redundant design of existing pressure measurement, multiple pressure sensors are arranged at multiple locations, and distributed measurement of multiple pressure sensors is used for information filtering. This design requires the preparation of multiple sensors and signal acquisition systems, which has defects such as high cost, complex design, complex wiring, and low reliability, and distributed measurement cannot measure a single pressure point. In addition, the use of distributed design also has defects such as large volume, low sensitivity, slow response rate, and poor stability, which makes it difficult to meet the use requirements of aerospace and other fields. In addition, the preparation method of the existing distributed residual pressure sensor also has the disadvantages of multiple packaging times, complex process, difficult operation, high cost, and low yield, which makes it difficult to achieve large-scale industrial application of sensors. Therefore, obtaining a dual-redundant pressure sensor with small size, high sensitivity, rapid response, good stability, and a matching preparation method with simple process, convenient operation, low cost, and high yield is of great significance for promoting the widespread use of pressure sensors in aerospace and other fields. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a dual redundant pressure sensor that combines a through-type and a differential pressure type with a small size, high sensitivity, rapid response and good stability, as well as a method for preparing the dual redundant pressure sensor with a simple process, convenient operation, low cost and high yield.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A dual redundant pressure sensor combining a through-type and a differential pressure type comprises a differential pressure type pressure sensitive chip and a through-type pressure sensitive chip stacked in sequence from bottom to top, wherein a bonding layer is provided between the differential pressure type pressure sensitive chip and the through-type pressure sensitive chip.

[0006] The above-mentioned dual redundant pressure sensor combining through-type and differential pressure type is further improved in that a pressure conducting hole is provided at the center of the bonding layer, and the pressure chambers of the differential pressure-sensitive chip and the through-type pressure-sensitive chip are connected to the outside through the pressure conducting hole.

[0007] The above-mentioned dual-redundant pressure sensor combining the through-type and the differential pressure type is further improved in that the pressure-conducting hole is aligned with the through hole of the through-type pressure-sensitive chip.

[0008] The above-mentioned dual redundant pressure sensor combining through-type and differential pressure type is further improved, and the through-type pressure-sensitive chip is one of a cross-beam stress concentration pressure-sensitive chip, an island membrane stress concentration pressure-sensitive chip, and a beam-groove combination stress concentration pressure-sensitive chip.

[0009] The above-mentioned dual-redundant pressure sensor combining the through-type and the differential pressure type is further improved, and the differential pressure type pressure-sensitive chip is a flat film type piezoresistive pressure-sensitive chip or an island film type piezoresistive pressure-sensitive chip.

[0010] The above-mentioned dual-redundant pressure sensor combining the through-type and the differential pressure type is further improved in that the thickness of the bonding layer is 200 μm to 1000 μm.

[0011] The above-mentioned dual-redundancy pressure sensor combining the through-type and the differential pressure type is further improved in that the material of the bonding layer is glass or silicon.

[0012] As a general technical concept, the present invention also provides a method for preparing a dual redundant pressure sensor combining a through-type and a differential pressure type, comprising the following steps:

[0013] S1, preparing a differential pressure varistor chip and a through-type varistor chip respectively;

[0014] S2, aligning the through-type pressure-sensitive chip with the bonding layer so that the pressure-conducting holes of the bonding layer correspond to the through holes of the through-type pressure-sensitive chip, and bonding the through-type pressure-sensitive chip with the bonding layer to form a double-layer structure;

[0015] S3. Align the differential pressure piezoresistance chip with the bonding layer so that the pressure-conducting hole of the bonding layer corresponds to the silicon cup of the differential pressure piezoresistance chip. Bond the differential pressure piezoresistance chip with the bonding layer to form a sandwich structure, thereby completing the preparation of a dual redundant pressure sensor combining the through-type and differential pressure types.

[0016] The above preparation method is further improved and further comprises the following steps:

[0017] S4. Slice the sandwich structure to obtain a dual redundant pressure sensor combining a through-type and a differential pressure type.

[0018] The above-mentioned preparation method is further improved, and the preparation method of the differential pressure type pressure sensitive chip comprises the following steps:

[0019] (a1) Cleaning the ion-implanted SOI wafer;

[0020] (a2) performing dry etching on the front side of the SOI wafer to form an electrode structure;

[0021] (a3) Depositing a metal electrode on the front side of the SOI wafer;

[0022] (a4) Wet etching is performed on the back side of the SOI wafer to form a strain diaphragm structure, thereby completing the preparation of the differential pressure varistor chip.

[0023] The above-mentioned preparation method is further improved, and the preparation method of the through-type pressure-sensitive chip comprises the following steps:

[0024] (b1) Cleaning the ion-implanted SOI wafer;

[0025] (b2) performing dry etching on the front side of the SOI wafer to form an electrode structure and remove the oxide layer at the through-hole position;

[0026] (b3) Depositing a metal electrode on the front side of the SOI wafer;

[0027] (b4) Wet etching is performed on the back side of the SOI wafer to form a strain diaphragm structure, thereby completing the preparation of the through-type varistor chip.

[0028] The above preparation method is further improved, wherein the bonding layer further comprises the following treatment before use:

[0029] (c1) cleaning the bonding layer;

[0030] (c2) Punching holes in the bonding layer to form pressure-conducting holes.

[0031] The above-mentioned preparation method is further improved. In step S2, a double-sided photolithography machine is used to align the through-type varistor chip with the bonding layer; and the through-type varistor chip and the bonding layer are bonded by anodic bonding.

[0032] The above-mentioned preparation method is further improved, in step S3, a double-sided photolithography machine is used to align the differential pressure type varistor chip with the bonding layer; and an anodic bonding method is used to bond the differential pressure type varistor chip with the bonding layer.

[0033] The above-mentioned preparation method is further improved, and the dual redundant pressure sensor combining the through-type and differential pressure types includes a differential pressure type pressure sensitive chip and a through-type pressure sensitive chip stacked in sequence from bottom to top, and a bonding layer is provided between the differential pressure type pressure sensitive chip and the through-type pressure sensitive chip to form a sandwich structure.

[0034] The above-mentioned preparation method is further improved in that a pressure-conducting hole is provided at the center of the bonding layer, and the pressure chambers of the differential pressure-type piezoresistance chip and the through-type piezoresistance chip are connected to the outside through the pressure-conducting hole.

[0035] The above-mentioned preparation method is further improved in that the pressure-conducting hole is aligned with the through hole of the through-type pressure-sensitive chip.

[0036] The above-mentioned preparation method is further improved, and the through-type varistor chip is one of a cross-beam stress concentration varistor chip, an island membrane stress concentration varistor chip, and a beam-groove combination stress concentration varistor chip.

[0037] The above-mentioned preparation method is further improved, and the differential pressure piezoresistive piezoresistive chip is a diaphragm type or island membrane type piezoresistive piezoresistive chip.

[0038] The above preparation method is further improved in that the thickness of the bonding layer is 200 μm to 1000 μm.

[0039] The above preparation method is further improved in that the material of the bonding layer is glass or silicon.

[0040] Compared with the prior art, the advantages of the present invention are:

[0041] (1) In view of the shortcomings of existing multi-redundant pressure sensors, such as large size, low sensitivity, slow response rate, and poor stability, the present invention creatively provides a dual-redundant pressure sensor combining a through-type and a differential pressure type. The through-type pressure-sensitive chip and the differential pressure-sensitive chip are stacked and bonded to form a sandwich structure. This structure ensures that the pressure medium flows into the through-type pressure-sensitive chip through the through-hole of the bonding rubbing and then exerts pressure on the differential pressure-sensitive chip. Therefore, when measuring a certain pressure point, the through-type pressure-sensitive chip and the differential pressure-sensitive chip can be used to collect pressure information, thereby realizing dual-redundant measurement of a single pressure point. In particular, when a certain pressure-sensitive chip fails, the system can still operate effectively. It has the advantages of high sensitivity, rapid response, good stability, etc. It is a new type of pressure sensor with excellent performance and easy use, high use value, and good application prospects.

[0042] (2) In view of the defects of the existing multi-redundant pressure sensor preparation methods, such as many packaging times, complex process, difficult operation, high cost, and low yield rate, as well as the large volume, low sensitivity, slow response rate, poor stability, etc., in the multi-redundant pressure sensors obtained therefrom, the present invention creatively provides a preparation method for a dual-redundant pressure sensor combining a through-type and a differential pressure type. First, the through-type pressure-sensitive chip and the differential pressure-sensitive chip are prepared separately, and then the through-type pressure-sensitive chip and the differential pressure-sensitive chip are stacked and bonded to form a sandwich structure, thereby preparing a dual-redundant pressure sensor with high sensitivity, rapid response, and good stability. In addition, the preparation method of the present invention can reduce the number and volume of pressure sensors, reduce the number of pressure sensor packaging times, and reduce the complexity of sensor wiring. It has the advantages of simple process, convenient operation, low cost, high yield rate, etc., is suitable for large-scale preparation, and is convenient for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0044] Figure 1 It is a schematic diagram of the three-dimensional structure of a dual redundant pressure sensor combining the through-type and the differential pressure type in Example 1 of the present invention.

[0045] Figure 2 It is a schematic diagram of the cross-sectional structure of a dual redundant pressure sensor combining the through-type and the differential pressure type in Example 1 of the present invention.

[0046] Figure 3 This is a flow chart of the preparation process of a dual redundant pressure sensor combining a through-type and a differential pressure type in Example 1 of the present invention.

[0047] Legend:

[0048] 1. Through-type varistor chip; 2. Bonding layer; 3. Differential pressure varistor chip. DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0050] Embodiment 1:

[0051] like Figure 1 and Figure 2As shown, a dual redundant pressure sensor combining through-type and differential pressure types includes a differential pressure-sensitive chip 3 and a through-type pressure-sensitive chip 1 stacked in sequence from bottom to top (the through-type pressure-sensitive chip refers to a pressure-sensitive diaphragm with an open hole feature, and the pressure fluid can pass through the pressure-sensitive diaphragm), and a bonding layer 2 is provided between the differential pressure-sensitive chip 3 and the through-type pressure-sensitive chip 1 to form a sandwich structure.

[0052] In this embodiment, a pressure conducting hole is provided in the center of the bonding layer 2, through which the pressure chambers of the differential pressure piezoresistance chip and the through-type piezoresistance chip are connected to the outside, thereby ensuring that the pressure medium can enter the pressure chamber through the through hole (the opening on the pressure-sensitive diaphragm) of the through-type piezoresistance chip, and enter the pressure chamber of the differential pressure piezoresistance chip after passing through the pressure conducting hole.

[0053] In this embodiment, the pressure conducting hole is aligned with the through hole of the through-type pressure-sensitive chip to facilitate the pressure medium to enter the pressure chamber of the sensor.

[0054] In this embodiment, the through-type varistor chip 1 is a cross-beam stress concentration varistor chip. In another embodiment, the through-type varistor chip 1 is an island film stress concentration varistor chip, or a beam-groove combined stress concentration varistor chip.

[0055] In this embodiment, the pressure-type piezoresistive piezoresistive chip 3 is a diaphragm-type piezoresistive piezoresistive chip. In another embodiment, the differential pressure-type piezoresistive chip 3 is a flat-film piezoresistive piezoresistive chip or an island-film piezoresistive piezoresistive chip.

[0056] In this embodiment, the thickness of the bonding layer 2 is 500 μm, and the material of the bonding layer 2 is glass. In another embodiment, the material of the bonding layer 2 is silicon.

[0057] A method for preparing a dual redundant pressure sensor combining a through-type and a differential pressure type in the above-mentioned embodiment, the preparation process flow chart thereof is as follows: Figure 3 As shown, the following steps are included:

[0058] (1) Preparation of differential pressure varistor chip:

[0059] (a) Cleaning: The ion-implanted SOI wafer is cleaned using a standard cleaning method.

[0060] (b) Preparation of front electrode: The front side of the SOI wafer is dry-etched to generate the electrode structure, and the metal electrode is deposited by ion beam plating.

[0061] (c) Etching the strain diaphragm: The back side of the SOI wafer is wet-etched using a KOH solution to form a strain diaphragm structure, thereby completing the preparation of the differential pressure varistor chip.

[0062] (2) Bonding glass preparation:

[0063] (d) Cleaning: Take a glass sheet with a thickness of 500 μm and perform RCA standard cleaning.

[0064] (e) Punching: Use laser to punch holes in the glass sheet to form pressure-conducting holes.

[0065] (3) Preparation of through-type pressure-sensitive chip:

[0066] (f) Cleaning: The ion-implanted SOI wafer is cleaned using a standard cleaning method.

[0067] (g) Preparation of front electrode and etching of through structure: The front electrode is formed by dry etching to generate the electrode structure and ion beam plating to deposit the metal electrode. The oxide layer at the through position is completely etched by dry etching to form a through hole.

[0068] (h) Etching the strain diaphragm: The SOI sheet is wet-etched using a KOH solution to form a strain diaphragm structure, thereby completing the preparation of the through-type varistor chip.

[0069] (4) Dual redundant pressure-sensitive chip bonding combining through-type and differential pressure type:

[0070] (a) Alignment: A double-sided photolithography machine is used to align the through-type pressure-sensitive wafer and the through-hole anode glass respectively to ensure that the through-hole of the glass corresponds to the through-hole of the through-type pressure-sensitive wafer to ensure pressure conduction.

[0071] (b) Anodic bonding: Anodic bonding is used to bond the through-type varistor wafer and the through-hole anode glass to form a double-layer structure.

[0072] (c) Alignment: A double-sided photolithography machine is used to align the double-layer structure and differential pressure sensitive wafer obtained in b) to ensure that the glass through hole corresponds to the membrane structure (silicon cup) of the differential pressure sensitive chip to ensure pressure conduction.

[0073] (d) Anodic bonding: The double-layer structure and differential pressure sensitive wafer obtained in b) are bonded by anodic bonding to form a sandwich structure.

[0074] (e) Slicing: Slicing the final sandwich structure to form a dual-redundant pressure-sensitive chip structure combining a through-type and a differential pressure type, thereby completing the preparation of a dual-redundant pressure sensor combining a through-type and a differential pressure type.

[0075] After testing, the dual redundant pressure sensor combining the through-type and differential pressure types prepared in Example 1 of the present invention has a sensitivity of 10mV / V, a cost of one-fifth of that of a conventional distributed dual redundant pressure sensor, and a service life of thirty years.

[0076] It can be seen that compared with the conventional distributed dual redundant pressure sensor, the dual redundant pressure sensor combining the through-type and differential pressure type of the present invention has higher sensitivity, faster response rate, lower cost, and longer service life; in addition, the dual redundant pressure sensor combining the through-type and differential pressure type of the present invention has a smaller volume, is more convenient to use, has fewer packaging times, and has a simpler wiring method. Therefore, the dual redundant pressure sensor combining the through-type and differential pressure type of the present invention stacks and bonds the through-type pressure sensitive chip and the differential pressure sensitive chip into a sandwich structure, so when measuring a certain pressure point position, the through-type pressure sensitive chip and the differential pressure sensitive chip can be used to collect pressure information, thereby realizing dual redundant measurement of a single pressure point, especially when a certain pressure sensitive chip fails, the system can still operate effectively, and has the advantages of high sensitivity, rapid response, good stability, etc. It is a new type of pressure sensor with excellent performance and easy use, high use value, and good application prospects. In addition, the preparation method of the dual redundant pressure sensor combining the through-type and the differential pressure type of the present invention can reduce the number and volume of pressure sensors, reduce the number of times the pressure sensors are packaged, and reduce the complexity of sensor wiring. It has the advantages of simple process, convenient operation, low cost, and high yield rate. It is suitable for large-scale preparation and convenient for industrial application.

[0077] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A dual redundant pressure sensor combining through-type and differential pressure type, characterized in that: It comprises a differential pressure type pressure sensitive chip and a through type pressure sensitive chip which are stacked in sequence from bottom to top, and a bonding layer is arranged between the differential pressure type pressure sensitive chip and the through type pressure sensitive chip.

2. The dual redundant pressure sensor combining through-type and differential pressure type according to claim 1, characterized in that: A pressure-conducting hole is provided at the center of the bonding layer, and the pressure chambers of the differential pressure-sensitive chip and the through-type pressure-sensitive chip are connected to the outside through the pressure-conducting hole.

3. The dual redundant pressure sensor combining through-type and differential pressure type according to claim 2, characterized in that: The pressure-conducting hole is aligned with the through hole of the through-type pressure-sensitive chip.

4. The dual redundant pressure sensor combining through-type and differential pressure type according to any one of claims 1 to 3, characterized in that: The through-type varistor chip is one of a cross-beam stress concentration varistor chip, an island membrane stress concentration varistor chip, and a beam-groove combination stress concentration varistor chip; the differential pressure varistor chip is a flat membrane piezoresistive varistor chip or an island membrane piezoresistive varistor chip; the thickness of the bonding layer is 200μm to 1000μm; the material of the bonding layer is glass or silicon.

5. A method for preparing a dual redundant pressure sensor combining a through-type and a differential pressure type, characterized in that: The following steps are involved: S1, preparing a differential pressure varistor chip and a through-type varistor chip respectively; S2, aligning the through-type pressure-sensitive chip with the bonding layer so that the pressure-conducting holes of the bonding layer correspond to the through holes of the through-type pressure-sensitive chip, and bonding the through-type pressure-sensitive chip with the bonding layer to form a double-layer structure; S3. Align the differential pressure piezoresistance chip with the bonding layer so that the pressure-conducting hole of the bonding layer corresponds to the silicon cup of the differential pressure piezoresistance chip. Bond the differential pressure piezoresistance chip with the bonding layer to form a sandwich structure, thereby completing the preparation of a dual redundant pressure sensor combining the through-type and differential pressure types.

6. The preparation method according to claim 5, characterized in that: The following steps are also included: S4. Slice the sandwich structure to obtain a dual redundant pressure sensor combining a through-type and a differential pressure type.

7. The preparation method according to claim 5 or 6, characterized in that: The method for preparing the differential pressure type pressure sensitive chip comprises the following steps: (a1) Cleaning the ion-implanted SOI wafer; (a2) performing dry etching on the front side of the SOI wafer to form an electrode structure; (a3) Depositing a metal electrode on the front side of the SOI wafer; (a4) performing wet etching on the back side of the SOI wafer to form a strain diaphragm structure, thereby completing the preparation of the differential pressure varistor chip; The method for preparing the through-type pressure-sensitive chip comprises the following steps: (b1) Cleaning the ion-implanted SOI wafer; (b2) performing dry etching on the front side of the SOI wafer to form an electrode structure and remove the oxide layer at the through-hole position; (b3) Depositing a metal electrode on the front side of the SOI wafer; (b4) performing wet etching on the back side of the SOI wafer to form a strain diaphragm structure, thereby completing the preparation of the through-type varistor chip; The bonding layer also includes the following treatments before use: (c1) cleaning the bonding layer; (c2) Punching holes in the bonding layer to form pressure-conducting holes.

8. The preparation method according to claim 5 or 6, characterized in that: In step S2, a double-sided photolithography machine is used to align the through-type pressure-sensitive chip with the bonding layer; and an anodic bonding method is used to bond the through-type pressure-sensitive chip with the bonding layer; In step S3, a double-sided photolithography machine is used to align the differential pressure type varistor chip with the bonding layer; and an anodic bonding method is used to bond the differential pressure type varistor chip with the bonding layer.

9. The preparation method according to claim 5 or 6, characterized in that: The dual redundant pressure sensor combining the through-type and differential pressure types comprises a differential pressure type pressure sensitive chip and a through-type pressure sensitive chip stacked in sequence from bottom to top, and a bonding layer is provided between the differential pressure type pressure sensitive chip and the through-type pressure sensitive chip to form a sandwich structure.

10. The preparation method according to claim 9, characterized in that: A pressure conducting hole is provided at the center of the bonding layer, through which the pressure chambers of the differential pressure varistor chip and the through-type varistor chip are connected to the outside; the pressure conducting hole is aligned with the through hole of the through-type varistor chip; the through-type varistor chip is one of a cross-beam stress concentration varistor chip, an island membrane stress concentration varistor chip, and a beam-groove combination stress concentration varistor chip; the differential pressure varistor chip is a diaphragm type or island membrane type piezoresistive varistor chip; the thickness of the bonding layer is 200μm to 1000μm; the material of the bonding layer is glass or silicon.

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