Sensor and electronic device

Abstract

The invention discloses a sensor and electronic equipment, and the sensor comprises a supporting structure which is internally provided with a cavity; the silicon thin film is arranged on the supporting structure, and at least one piezoresistor and at least one heavily doped interconnection resistor are arranged at the positions, corresponding to the cavity, of the silicon thin film; the metal wire is electrically connected with the piezoresistor and the heavily doped interconnection resistor, and a groove is formed between the metal wire and the cavity so as to protect the piezoresistor from being influenced by the stress of the metal wire. According to the sensor, the groove is formed between the metal wire and the cavity of the supporting structure, stress isolation is carried out on the area of the metal wire through the groove, and the thermal hysteresis performance of the chip is improved.

Description

Technical Field

[0001] The present invention relates to the field of micro-mechanical electronics, and more specifically, to a sensor and electronic equipment. Background Art

[0002] Piezoresistive pressure sensors have the characteristics of small size, light weight, easy integration, ultra-high sensitivity and resolution. In the field of consumer electronics, pressure sensors can provide altitude information reference for mobile phones and drones. In the biomedical field, they are also used as electronic blood pressure monitors, respiratory flow meters, etc. to provide health monitoring for people. In the automotive field, they can also be used for tire pressure monitoring. With the development of information technology, combined with other types of sensors to form intelligent control systems, pressure sensors will be more widely used in smart homes, manufacturing and other fields in the future.

[0003] As the application field expands, the requirements for pressure sensors are getting higher and higher, such as high precision and higher reliability, better thermal hysteresis and anti-interference ability, etc. The thermal stress caused by the thermal mismatch between the different metal traces on the chip surface and the CTE (coefficient of thermal expansion, CTE) of the silicon material will greatly affect the thermal hysteresis performance of the chip.

[0004] Therefore, the thermal hysteresis performance of traditional pressure sensor chips needs to be further improved. At the same time, the noise level and reliability of traditional piezoresistive pressure sensors will be affected to a certain extent because the piezoresistors are susceptible to external electromagnetic interference. Summary of the invention

[0005] An object of the present invention is to provide a new technical solution for sensors and electronic devices, which can at least solve the problems such as thermal hysteresis existing in the prior art.

[0006] According to a first aspect of the present invention, a sensor is provided, comprising: a support structure, wherein a cavity is provided in the support structure; a silicon film, wherein the silicon film is provided on the support structure, and wherein at least one varistor and at least one heavily-doped interconnect resistor are provided at a position of the silicon film corresponding to the cavity; and a metal wiring, wherein the metal wiring is electrically connected to the varistor and the heavily-doped interconnect resistor, and a groove is provided between the metal wiring and the cavity to protect the varistor from being affected by the stress of the metal wiring.

[0007] Optionally, the silicon film is etched with the groove at the periphery of the cavity, and the etching depth of the groove is located above the silicon film.

[0008] Optionally, the groove is etched around the periphery of the metal wiring, and the etching depth of the groove is located above the silicon film.

[0009] Optionally, an electromagnetic isolation layer is deposited on the groove.

[0010] Optionally, the electromagnetic isolation layer is a composite material of Ag / Si3N4 or a metal material.

[0011] Optionally, there are at least four varistors, and the at least four varistors are spaced apart and distributed in a ring shape to form a Wheatstone bridge.

[0012] Optionally, the metal wiring is made of aluminum material, aluminum-silicon-copper composite material or aluminum-copper composite material.

[0013] Optionally, the electromagnetic isolation layer (60) is a mesh structure.

[0014] Optionally, a passivation layer, a first protective layer, and a second protective layer are sequentially provided on the silicon film, wherein both the first protective layer and the second protective layer are nitride layers.

[0015] A second aspect of the present invention provides an electronic device, comprising the sensor described in the above embodiment, wherein the sensor is an absolute pressure sensor or a differential pressure sensor.

[0016] The sensor of the present invention provides a groove between the metal wiring and the cavity of the support structure, and utilizes the groove to perform stress isolation on the area of ​​the metal wiring, so as to improve the thermal hysteresis performance of the chip.

[0017] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0019] Figure 1 is a plan view of a sensor according to an embodiment of the present invention;

[0020] Figure 2 yes Figure 1 Section view of midline AA;

[0021] Figure 3 yes Figure 1 Section view of midline BB;

[0022] Figure 4 is another plan view of a sensor according to an embodiment of the present invention;

[0023] Figure 5 yes Figure 4 Section view of the midline CC.

[0024] Reference numerals:

[0025] Support structure 10; cavity 11;

[0026] Silicon film 20;

[0027] Varistor 31; heavily doped interconnect resistor 32;

[0028] Metal trace 40;

[0029] Groove 50;

[0030] Electromagnetic isolation layer 60;

[0031] Oxide layer 71 ; passivation layer 72 ; first protective layer 73 ; second protective layer 74 . DETAILED DESCRIPTION

[0032] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0033] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0034] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0035] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0036] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0037] In the specification and claims of the present invention, if the term "first" or "second" is involved, it may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the related objects are in an "or" relationship.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" involved 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 a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] The sensor according to the embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0041] like Figures 1 to 5 As shown, the sensor according to the embodiment of the present invention includes a support structure 10 , a silicon film 20 and a metal trace 40 .

[0042] Specifically, a cavity 11 is provided in the support structure 10. A silicon film 20 is provided on the support structure 10, and at least one varistor 31 and at least one heavily doped interconnect resistor 32 are provided at positions of the silicon film 20 corresponding to the cavity 11. A metal wiring 40 is electrically connected to the varistor 31 and the heavily doped interconnect resistor 32, and a groove 50 is provided between the metal wiring 40 and the cavity 11 to protect the varistor 31 from being affected by the stress of the metal wiring 40.

[0043] In other words, see Figures 1 to 5 The sensor according to the embodiment of the present invention is mainly composed of a support structure 10, a silicon film 20 and a metal wiring 40. The support structure 10 is a supporting silicon structure at the bottom of the sensor, and a cavity 11 is provided in the support structure 10. The silicon film 20 can be provided on the support structure 10, such as Figure 1 and Figure 4As shown, at least one piezoresistor 31 and at least one heavily doped interconnect resistor 32 are arranged at the position of the silicon film 20 corresponding to the cavity 11. The piezoresistor 31 can measure the pressure according to the change in the resistance value of the piezoresistor 31 when the sensor pressure changes. The heavily doped interconnect resistor 32 is an interconnect resistor formed by heavy P-type doping. The metal wiring 40 is electrically connected to the piezoresistor 31 and the heavily doped interconnect resistor 32 to realize the series connection between the piezoresistor 31 and the heavily doped interconnect resistor 32. Figures 1 to 5 As shown, a groove 50 is provided between the metal wiring 40 and the cavity 11. By providing the groove 50 between the metal wiring 40 and the cavity 11 of the support structure 10, the groove 50 is used to perform stress isolation on the area of ​​the metal wiring 40, so as to improve the thermal hysteresis performance of the chip.

[0044] In the present invention, due to the difference in CTE (coefficient of thermal expansion, CTE for short) between the metal on the chip surface and the silicon material, the stress at the piezoresistor position will change during the chip temperature change, affecting the output, and the metal on the chip surface will also affect the thermal hysteresis performance of the chip. At the same time, the piezoresistive pressure sensor is susceptible to external electromagnetic interference, which in turn affects the noise and reliability performance of the sensor. Based on the above problems, the purpose of the present invention is to provide a MEMS (Micro-Electro-Mechanical System: MEMS for short) pressure chip with good thermal hysteresis performance and anti-electromagnetic interference capability.

[0045] The pressure MEMS structure (sensor) with the trench 50 isolation of the present invention can isolate the structural stress of the metal wiring 40 on the chip surface and improve the thermal hysteresis performance of the pressure sensor.

[0046] Therefore, according to the sensor of the embodiment of the present invention, a groove 50 is provided between the metal wiring 40 and the cavity 11 of the support structure 10, and the groove 50 is used to perform stress isolation on the area of ​​the metal wiring 40, so as to improve the thermal hysteresis performance of the chip.

[0047] According to an embodiment of the present invention, the silicon film 20 is etched with a groove 50 at the periphery of the cavity 11, and the etching depth of the groove 50 is located above the silicon film 20. In other words, Figures 1 to 3 As shown, the silicon film 20 may be a P-type sensitive film, and a groove 50 may be etched on the silicon film 20 at the periphery of the cavity 11, and the etching depth of the groove 50 is located above the silicon film 20. By etching the groove 50 at the periphery of the cavity 11, the groove 50 is used to perform stress isolation on the area of ​​the metal wiring 40, so as to improve the thermal hysteresis performance of the chip.

[0048] According to one embodiment of the present invention, Figure 4 and Figure 5 As shown, a groove 50 is etched around the metal trace 40, and the etching depth of the groove 50 is located above the silicon film 20. By setting the groove 50 isolation structure at the edge of the metal trace 40, it is used to prevent the stress generated by the metal CTE thermal mismatch caused by the change of the external environment on the metal trace 40, thereby effectively improving the thermal hysteresis performance of the pressure MEMS sensor.

[0049] According to one embodiment of the present invention, Figures 1 to 3 As shown, an electromagnetic isolation layer 60 is deposited on the groove 50. The electromagnetic isolation layer 60 is formed by a deposition process in the groove 50 to protect the pressure sensitive resistor from electromagnetic interference from the external environment. The pressure MEMS structure (sensor) with the isolation of the groove 50 of the present invention can isolate the structural stress of the metal wiring 40 on the chip surface and improve the thermal hysteresis performance of the pressure sensor.

[0050] According to one embodiment of the present invention, the electromagnetic isolation layer 60 is a composite material or metal material of Ag / Si3N4. In other words, the electromagnetic isolation layer 60 can be made of a composite material or metal material of Ag / Si3N4, such as copper, aluminum and other metal materials, to shield the external electromagnetic interference and improve the anti-interference ability and reliability performance of the pressure sensor.

[0051] According to one embodiment of the present invention, Figure 1 and Figure 4 As shown, there are at least four piezoresistors 31, and at least four piezoresistors 31 are spaced apart and distributed in a ring shape, for example, the four piezoresistors 31 are distributed in a rectangular or diamond shape. At least four piezoresistors 31 can form a Wheatstone bridge. When the pressure of the sensor changes, the piezoresistors 31 can measure the pressure according to the change in the resistance value of the piezoresistors 31.

[0052] According to an embodiment of the present invention, the metal wiring 40 is made of aluminum material, aluminum-silicon-copper composite material or aluminum-copper composite material. The metal wiring 40 can be made of aluminum material, ALSiCu or ALCu material, which has good conductivity and low cost.

[0053] According to one embodiment of the present invention, Figure 2 , Figure 3 and Figure 5 As shown, an oxide layer 71 is disposed between the support structure 10 and the silicon film 20. That is, an oxide layer 71 may be deposited between the support structure 10 and the silicon film 20 to achieve protection between the support structure 10 and the silicon film 20.

[0054] According to an embodiment of the present invention, the electromagnetic isolation layer 60 is a mesh structure, which can shield the external electromagnetic interference and improve the anti-interference capability and reliability performance of the pressure sensor.

[0055] According to an embodiment of the present invention, a passivation layer 72 , a first protective layer 73 , and a second protective layer 74 are sequentially disposed on the silicon film 20 , wherein the first protective layer 73 and the second protective layer 74 are both nitride layers.

[0056] That is to say, Figure 2 , Figure 3 and Figure 5 As shown, a passivation layer 72, a first protective layer 73 and a second protective layer 74 may be sequentially arranged on the silicon film 20, wherein the first protective layer 73 and the second protective layer 74 are nitride layers respectively. A passivation layer 72 covering the sensitive film (silicon film 20) may be an oxidizing layer, and the covering layer (first protective layer 73) and the passivation protective layer (second protective layer 74) on the passivation layer 72 may be a nitride layer, which covers and protects the metal wiring 40. In the actual manufacturing process, the first protective layer 73 and the second protective layer 74 are both formed by a deposition process, and a passivation layer is first deposited on the passivation layer 72 as the first protective layer 73. After the deposition is completed, another passivation layer is deposited on the first protective layer 73 as the second protective layer 74, wherein the materials deposited on the first protective layer 73 and the second protective layer 74 are the same, but the deposition parameters (for example, deposition time, speed, thickness, etc.) are different.

[0057] In summary, according to the sensor of the embodiment of the present invention, the groove 50 is provided between the metal wiring 40 and the cavity 11 of the support structure 10, and the region of the metal wiring 40 is stress-isolated by the groove 50, so as to improve the thermal hysteresis performance of the chip. At the same time, the electromagnetic isolation layer 60 is provided to shield the external electromagnetic interference, thereby improving the anti-interference ability and reliability performance of the pressure sensor.

[0058] Of course, for those skilled in the art, other structures and working principles of the sensor are understandable and achievable, and will not be described in detail in the present invention.

[0059] According to the second aspect of the present invention, an electronic device is provided, comprising the sensor in the above embodiment. Since the sensor according to the embodiment of the present invention has the above technical effects, the electronic device according to the embodiment of the present invention should also have the corresponding technical effects, that is, the electronic device of the present invention can use the groove 50 to stress isolate the area of ​​the metal wiring 40 by adopting the sensor, so as to improve the thermal hysteresis performance of the chip. At the same time, by setting the electromagnetic isolation layer 60, shielding of external electromagnetic interference can be achieved, thereby improving the anti-interference ability and reliability performance of the pressure sensor.

[0060] Of course, for those skilled in the art, other structures and working principles of the electronic device are understandable and achievable, and will not be described in detail in the present invention.

[0061] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A sensor, characterized in that: include: A support structure (10), wherein a cavity (11) is provided in the support structure (10); A silicon film (20), the silicon film (20) being arranged on the support structure (10), and at least one varistor (31) and at least one heavily-doped interconnect resistor (32) being arranged at a position of the silicon film (20) corresponding to the cavity (11); A metal wiring (40) is electrically connected to the varistor (31) and the heavily-doped interconnect resistor (32), and a groove (50) is provided between the metal wiring (40) and the cavity (11) to protect the varistor (31) from being affected by the stress of the metal wiring (40).

2. The sensor according to claim 1, characterized in that The silicon film (20) is etched with the groove (50) at the periphery of the cavity (11), and the etching depth of the groove (50) is located above the silicon film (20).

3. The sensor according to claim 1, characterized in that The groove (50) is etched around the periphery of the metal wiring (40), and the etching depth of the groove (50) is located above the silicon film (20).

4. The sensor according to claim 1, characterized in that An electromagnetic isolation layer (60) is deposited on the groove (50).

5. The sensor according to claim 4, characterized in that The electromagnetic isolation layer (60) is a composite material of Ag / Si3N4 or a metal material.

6. The sensor according to claim 1, characterized in that There are at least four varistors (31), and the at least four varistors (31) are spaced apart and distributed in a ring shape to form a Wheatstone bridge.

7. The sensor according to claim 1, characterized in that The metal wiring (40) is made of aluminum material, aluminum-silicon-copper composite material or aluminum-copper composite material.

8. The sensor according to claim 4, characterized in that The electromagnetic isolation layer (60) is a mesh structure.

9. The sensor according to claim 1, characterized in that A passivation layer (72), a first protective layer (73) and a second protective layer (74) are sequentially arranged on the silicon film (20), wherein the first protective layer (73) and the second protective layer (74) are both nitride layers.

10. An electronic device, characterized in that: The sensor comprises the sensor described in any one of claims 1 to 9, wherein the sensor is an absolute pressure sensor or a differential pressure sensor.

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