Pressure sensor, preparation method thereof and electronic equipment

Abstract

The invention discloses a pressure sensor, a preparation method thereof and electronic equipment. The pressure sensor comprises a substrate and a sensitive body, wherein the sensitive body comprises a base and a sensitive film which are connected with each other; a first cavity part is formed in the position, corresponding to the sensitive film, of the substrate; the base and the substrate are stacked along a first direction, and the first direction corresponds to the thickness direction of the substrate; a gap part is arranged between the base and the substrate, and the gap part is communicated with the first cavity part; the substrate is provided with a first surface far away from the substrate and a second surface close to the substrate, a groove part is formed in the substrate, and the groove part extends into the substrate from the first surface and / or the second surface.

Description

Technical Field

[0001] This application relates to the field of electronic product technology, and more specifically, to a pressure sensor, a method for manufacturing the same, and an electronic device thereof. Background Technology

[0002] In the field of sensor technology, micro-electro-mechanical systems (MEMS) differential pressure sensors are an important type of sensing device, widely used in many fields such as industrial control, automotive electronics, medical equipment, and consumer electronics. They are used to accurately measure the pressure difference between two sides, providing key data for the precise control and monitoring of the system.

[0003] Traditional MEMS differential pressure products have certain limitations in structural design. In actual use, when the chip motherboard or packaging structure is subjected to stress by external factors, due to the mechanical relationship between the structures, the external stress will be transmitted from the substrate to the pressure-sensitive membrane. As the core sensing component of the MEMS differential pressure sensor, the pressure-sensitive membrane's surface piezoresistor is extremely sensitive to pressure changes; the transmission of external stress will cause a change in the stress state of the piezoresistor, thereby causing unexpected changes in the piezoresistor's output signal.

[0004] This variation in varistor output caused by external stress interference has a significant negative impact on sensor performance. From a long-term stability perspective, as usage time increases, repeated external stress on the sensor causes the varistor's output characteristics to gradually deviate from the initial set value, leading to decreased measurement accuracy and reduced reliability. This not only affects the system control accuracy based on the sensor data but may also cause system misjudgments or malfunctions, increasing equipment maintenance costs and operational risks.

[0005] In view of this, a new technical solution is needed to solve the above-mentioned technical problems. Summary of the Invention

[0006] One objective of this application is to provide a new technical solution for a pressure sensor, its fabrication method, and an electronic device thereof.

[0007] According to a first aspect of this application, a pressure sensor is provided, the pressure sensor comprising:

[0008] Substrate;

[0009] A sensitive body, the sensitive body comprising a substrate and a sensitive membrane interconnected thereto; the substrate having a first cavity portion formed at a position corresponding to the sensitive membrane;

[0010] The substrate and the substrate are stacked along a first direction corresponding to a thickness direction of the substrate.

[0011] A gap portion is provided between the substrate and the substrate, and the gap portion is in communication with the first cavity portion.

[0012] The substrate has a first surface away from the substrate and a second surface close to the substrate, and the substrate is formed with a groove portion extending from the first surface and / or the second surface to the inside of the substrate.

[0013] Optionally, the thickness of the sensitive film is less than the depth of the groove portion.

[0014] Optionally, the groove portion includes a first groove and a second groove, the first groove extending from the first surface to the inside of the substrate; the second groove extending from the second surface to the inside of the substrate, and the second groove being in communication with the gap portion.

[0015] Optionally, the first groove and the second groove are both annular grooves arranged around the sensitive film.

[0016] Optionally, the number of first grooves is the same as the number of second grooves.

[0017] Optionally, the number of first grooves is greater than the number of second grooves, or the number of second grooves is greater than the number of first grooves.

[0018] According to a second aspect of the present application, a preparation method of the pressure sensor of the first aspect is provided, and the preparation method comprises:

[0019] A first silicon substrate is provided, the first silicon substrate is etched to form a first cavity portion, and the side of the first silicon substrate with the first cavity portion is surface treated to form an oxide layer;

[0020] The surface of the first silicon substrate with the oxide layer and / or the other surface opposite to it are etched to form a groove portion;

[0021] A second silicon substrate is provided, and the first silicon substrate is stacked on the second silicon substrate with the oxide layer facing the second silicon substrate;

[0022] The second silicon substrate is etched to form a second cavity portion, and the second cavity portion is in communication with the first cavity portion;

[0023] A gap portion is etched between the first silicon substrate and the second silicon substrate.

[0024] Optionally, the groove portion is formed by dry etching or formed by wet etching.

[0025] Optionally, the etching of the second silicon substrate to form the second cavity portion is performed by wet etching first and then by dry etching.

[0026] Optionally, the gap portion is formed by wet etching.

[0027] According to a third aspect of the present application, an electronic device is provided, which comprises the pressure sensor according to the first aspect.

[0028] In the pressure sensor provided by the embodiments of the present application, the gap portion is arranged between the substrate and the base of the sensitive body, and the groove portion is formed in the base; the gap portion and the groove portion function like a spring, effectively absorbing the effect of external stress, so that the sensitive film is isolated from the external stress to a certain extent, reducing the degree of transmission of the external stress to the sensitive film through the substrate, i.e., reducing the influence of the external stress on the sensitive film, improving the measurement accuracy and working stability of the pressure sensor.

[0029] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the following drawings. BRIEF DESCRIPTION OF DRAWINGS

[0030] The accompanying drawings incorporated in and forming a part of the specification, illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application.

[0031] Fig. la is a sectional structure schematic view of a pressure sensor according to an embodiment of the present application;

[0032] Fig. lb is a schematic view of groove portion arrangement in a pressure sensor according to an embodiment of the present application;

[0033] Fig. lc is a schematic view of groove portion arrangement in a pressure sensor according to an embodiment of the present application;

[0034] Fig. Id is a schematic view of groove portion arrangement in a pressure sensor according to an embodiment of the present application;

[0035] Figs. 2a-2g is a process step schematic view of a preparation method of a pressure sensor according to an embodiment of the present application.

[0036] BRIEF DESCRIPTION OF DRAWINGS

[0037] 1, pressure sensor; 11, substrate; 110, second cavity portion; 12, sensitive body; 121, base; 122, sensitive film; 123, groove portion; 1231, first groove; 1232, second groove; 120, first cavity portion; 100, gap portion. DETAILED DESCRIPTION

[0038] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of the components and steps set forth in the examples, as well as the numerical expressions and values, are not limitations on the scope of the present application, unless otherwise specifically stated.

[0039] The following description of at least one example embodiment is merely illustrative in nature and is in no way limiting to the scope of the application or its applications or uses.

[0040] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein, but should be considered as part of the specification, where appropriate.

[0041] In all of the examples shown and discussed herein, any specific values should be interpreted as merely illustrative, and not as a limitation on the scope of the exemplary embodiments.

[0042] It should be noted that like reference numerals and letters in the various figures indicate similar items, and thus, once any term is defined in the context of a particular figure, further discussion of that term need not be repeated in subsequent figures. It is to be expressly understood that such is in no way limiting to the scope of the application, as described.

[0043] SUMMARY Figs. la-Id As shown, according to one embodiment of the present application, a pressure sensor 1 is provided. The pressure sensor 1 includes a substrate 11 and a sensitive body 12, the sensitive body 12 including a base 121 and a sensitive film 122 connected to each other; the base 121 is formed with a first cavity portion 120 at a position corresponding to the sensitive film 122;

[0044] The base 121 and the substrate 11 are stacked along a first direction, the first direction corresponding to a thickness direction of the substrate 11; a gap portion 100 is provided between the base 121 and the substrate 11, the gap portion 100 being in communication with the first cavity portion 120;

[0045] The base 121 has a first surface away from the substrate 11 and a second surface close to the substrate 11, the base 121 is formed with a groove portion 123, the groove portion 123 extending from the first surface and / or the second surface to the inside of the base 121.

[0046] The pressure sensor 1 provided by the embodiment of the present application comprises a substrate 11 and a sensitive body 12; wherein the sensitive body 12 comprises a substrate 121 and a sensitive film 122 connected with each other, specifically, the sensitive film 122 is arranged at the middle part of the substrate 121, and the substrate 121 is arranged around the sensitive film 122; further, a pressure-sensitive resistor is arranged on the sensitive film 122.

[0047] In the pressure sensor 1 provided by the embodiment of the present application, since the gap part 100 is arranged between the substrate 11 and the substrate 121 of the sensitive body 12, and the gap part 100 is in communication with the first cavity part 120 arranged in the sensitive body 12 and corresponding to the sensitive film 122; therefore, the substrate 121 and the substrate 11 are not rigidly connected, but are flexibly connected through the gap part 100; and the groove part 123 is formed in the substrate 121; the gap part 100 and the groove part 123 play a role similar to a spring, can effectively absorb the effect of external stress, so that the sensitive film 122 is isolated from the external stress to a certain extent, reduces the degree of transmission of the external stress to the sensitive film 122 through the substrate 11, that is, reduces the influence of the external stress on the sensitive film 122, improves the measurement accuracy and working stability of the pressure sensor 1. The pressure sensor 1 provided by the embodiment of the present application can effectively solve the problem of interference of external stress on the pressure-sensitive film and the pressure-sensitive resistor in the traditional MEMS differential pressure product, and improve the long-term stability of the sensor under complex working conditions.

[0048] Optionally, the groove part 123 is arranged in extension along the first direction (that is, the thickness direction of the substrate 121 and the substrate 11), which can enhance the buffering capacity of the groove part 123 to stress, and the process implementation of the groove part 123 is relatively simple.

[0049] Referring to Fig. la As shown in the figure, in one embodiment, the thickness of the sensitive film 122 is less than the depth of the groove part 123.

[0050] In this specific example, the thickness of the sensitive film 122 is arranged to be less than the depth of the groove part 123. In this way, the stress condition of the sensitive film 122 can be further optimized; the thinner sensitive film 122 is more sensitive to pressure changes, and the depth of the groove part can better play the role of buffering and isolating stress, so that the sensitive film can respond more accurately when subjected to pressure, while reducing external interference and improving the performance and stability of the sensor. For example, when the external air pressure changes slightly, the sensitive film 122 can sense the pressure change, while the groove part 123 is not affected.

[0051] Referring to Figs. lb-IdAs shown, in one embodiment, the groove portion 123 includes a first groove 1231 extending from the first surface to the interior of the base 121, and a second groove 1232 extending from the second surface to the interior of the base 121, the second groove 1232 being in communication with the gap portion 100.

[0052] In this specific example, the groove portion 123 is formed from both the first surface and the second surface to the interior of the base 121, and the second groove 1232 formed on the second surface is in communication with the gap portion 100. This can more comprehensively isolate the sensitive film 122 from stress from different directions, and the first groove 1231 and the second groove 1232 work together to further reduce the influence of external stress on the sensitive film, and improve the anti-interference ability and long-term stability of the sensor.

[0053] Referring to Fig. la As shown, in one embodiment, the first groove 1231 and the second groove 1232 are both annular grooves arranged around the sensitive film 122.

[0054] In this specific example, the first groove 1231 and the second groove 1232 are both annular grooves arranged around the sensitive film 122. The design of the annular groove can uniformly disperse and isolate external stress from all directions, so that the sensitive film 122 is in a relatively stable stress environment, and no matter which direction the external stress comes from, it can be effectively buffered and isolated by the annular groove, thereby ensuring the measurement accuracy and working stability of the sensitive film 122.

[0055] Referring to Fig. lc As shown, in one embodiment, the number of the first grooves 1231 is the same as the number of the second grooves 1232.

[0056] In this specific example, the number of the first grooves 1231 is the same as the number of the second grooves 1232, and the symmetrical arrangement helps to provide uniform stress isolation effect in all directions, so that the stress on the sensitive film 122 in different directions is more balanced, the measurement error caused by uneven stress distribution is reduced, and the overall performance of the sensor is improved.

[0057] Referring to Fig. Id As shown, in one embodiment, the number of the first grooves 1231 is greater than the number of the second grooves 1232.

[0058] In this specific example, considering that the second grooves 1232 are in communication with the gap portion 100, they can directly cooperate with the gap portion 100 to buffer external stress, and therefore the number of the first grooves 1231 is set to be greater than that of the second grooves 1232, which can also achieve a good stress isolation effect. However, in other embodiments, according to different application scenarios and performance requirements, the number of the second grooves 1232 can also be set to be greater than that of the first grooves 1231.

[0059] Referring to Figs. 2a-2g According to another embodiment of the present application, a method for manufacturing the pressure sensor as described above is provided, and the method comprises:

[0060] S101, referring to Fig. 2a A first silicon substrate is provided, and the first silicon substrate is etched to form a first cavity portion 120. One side of the first silicon substrate on which the first cavity portion 120 is formed is surface treated to form an oxide layer O. The structure of the first silicon substrate corresponding to the first cavity portion 120 forms a sensitive film 122, and the remaining structure surrounding the sensitive film 122 forms a substrate 121.

[0061] S102, referring to Fig. 2a , Fig. 2b The surface of the first silicon substrate having the oxide layer O and / or the other surface opposite to it is etched to form a groove portion 123.

[0062] S103, referring to Fig. 2c A second silicon substrate is provided, and the first silicon substrate is stacked on the second silicon substrate with the oxide layer O facing the second silicon substrate. Then, referring to Fig. 2d The sensitive film 122 portion of the first silicon substrate is manufactured into a piezoresistor, a metal pad, and a passivation layer.

[0063] S104, referring to Fig. 2e , Fig. 2f The second silicon substrate is etched to form a second cavity portion 110, and the second cavity portion 110 is in communication with the first cavity portion 120. At this time, the second silicon substrate forms a substrate 11.

[0064] S105, referring to Fig. 2g The first silicon substrate and the second silicon substrate are etched to form a gap portion 100.

[0065] In the method for manufacturing the pressure sensor provided in the embodiments of the present application, through a reasonable manufacturing process, each structure required by the pressure sensor, such as the first cavity portion 120, the groove portion 123, the second cavity portion 110 and the gap portion 100, can be accurately formed, so as to ensure that the sensor has good performance and stability.

[0066] In one embodiment, the groove portion 123 is formed by dry etching or wet etching.

[0067] In this specific example, the groove portion 123 is formed by dry etching or wet etching, and different etching methods have different characteristics. Dry etching has higher precision and can form a relatively regular groove shape; wet etching can have better etching effect and selectivity on some materials. According to actual needs, a suitable etching method can be selected to better control the size and shape of the groove portion 123, thereby optimizing the performance of the sensor.

[0068] Referring to FIGS. 1 to 3, Fig. 2e , Fig. 2f In one embodiment, the etching of the second silicon substrate to form the second cavity portion 110 is performed by wet etching first and then by dry etching.

[0069] In this specific example, when the second silicon substrate is etched to form the second cavity portion 110, wet etching is performed first and then dry etching is performed. Wet etching can quickly remove most of the material and improve etching efficiency; dry etching can finely trim the structure after wet etching, so as to ensure the size precision and shape regularity of the second cavity portion. This combined etching method allows the second silicon substrate (substrate 11) to have a larger thickness, thereby further reducing the influence of stress on the sensitive film 122.

[0070] In one embodiment, the gap portion 100 is formed by wet etching.

[0071] In this specific example, the gap portion 100 is formed by wet etching. Wet etching can control the etching depth and range to some extent, and can better form the required gap portion structure, so that the sensitive film is suspended and arranged, further reducing the influence of external stress on the sensitive film and improving the stability of the sensor.

[0072] According to still another embodiment of the present application, an electronic device is provided, which includes the pressure sensor 1 as described above.

[0073] The electronic device provided by the embodiments of the present application has a more accurate pressure measurement function due to the pressure sensor 1, and the sensor itself has higher stability and anti-interference capability, so that the electronic device can maintain good performance in the long-term use process, reduce the measurement error caused by sensor drift and other problems, and improve the overall quality of the electronic device.

[0074] The difference between the various embodiments is mainly described in the above embodiments, and the optimization features different between the various embodiments can be combined to form a better embodiment as long as they are not contradictory. In view of the brevity of the writing, it will not be repeated here.

[0075] Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration, but not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A pressure sensor, characterized in that, The pressure sensor includes: Substrate (11); The sensor (12) includes a substrate (121) and a sensitive membrane (122) connected to each other; the substrate (121) has a first cavity (120) formed at a position corresponding to the sensitive membrane (122); The substrate (121) and the substrate (11) are stacked along a first direction, which corresponds to the thickness direction of the substrate (11); A gap (100) is provided between the substrate (121) and the substrate (11), and the gap (100) communicates with the first cavity (120); The substrate (121) has a first surface away from the substrate (11) and a second surface close to the substrate (11), and the substrate (121) is formed with a groove (123) extending from the first surface and / or the second surface into the interior of the substrate (121).

2. The pressure sensor according to claim 1, characterized in that, The thickness of the sensitive membrane (122) is less than the depth of the groove (123).

3. The pressure sensor according to claim 1 or 2, characterized in that, The groove portion (123) includes a first groove (1231) and a second groove (1232), the first groove (1231) extending from the first surface to the interior of the substrate (121); the second groove (1232) extending from the second surface to the interior of the substrate (121), and the second groove (1232) communicating with the gap portion (100).

4. The pressure sensor according to claim 3, characterized in that, Both the first groove (1231) and the second groove (1232) are annular grooves arranged around the sensitive membrane (122).

5. The pressure sensor according to claim 4, characterized in that, The number of the first groove (1231) is the same as the number of the second groove (1232).

6. The pressure sensor according to claim 4, characterized in that, The number of the first groove (1231) is greater than the number of the second groove (1232), or the number of the second groove (1232) is greater than the number of the first groove (1231).

7. A method for manufacturing a pressure sensor as described in any one of claims 1-6, characterized in that, The preparation method includes: A first silicon substrate is provided, and the first silicon substrate is etched to form a first cavity (120). The side of the first silicon substrate where the first cavity (120) is formed is surface treated to form an oxide layer. The surface of the first silicon substrate having an oxide layer and / or the opposite surface are etched to form a groove (123); A second silicon substrate is provided, wherein the first silicon substrate is stacked on the second silicon substrate with the oxide layer facing the second silicon substrate; The second silicon substrate is etched to form a second cavity (110), and the second cavity (110) is connected to the first cavity (120); An interstic space (100) is formed between the first silicon substrate and the second silicon substrate.

8. The pressure sensor according to claim 7, characterized in that, The groove (123) is formed by dry etching or by wet etching.

9. The pressure sensor according to claim 7, characterized in that, The etching of the second silicon substrate to form the second cavity (110) is performed by first wet etching and then dry etching.

10. The pressure sensor according to claim 7, characterized in that, The gap (100) is formed by wet etching.

11. An electronic device, characterized in that, The electronic device includes a pressure sensor (1) as described in any one of claims 1-6.

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