MEMS pressure sensor, manufacturing method thereof and electronic device

Abstract

The invention provides an MEMS pressure sensor, a manufacturing method thereof and an electronic device, and the method comprises the steps: providing a first substrate and a second substrate, forming a first pressure structure on the first substrate, and forming a second pressure structure on the second substrate; bonding the first pressure structure and the second pressure structure; the first substrate is removed, the first pressure structure and the second pressure structure jointly form a third pressure structure, the third pressure structure comprises a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer and a fifth electrode layer which are arranged at intervals from top to bottom, and a dielectric layer is formed between every two adjacent electrode layers; and cavities penetrating through the dielectric layers are formed in the dielectric layers. According to the scheme, the multiple electrode layers arranged from bottom to top are formed, the multiple electrode layers form the first capacitor, the second capacitor, the third capacitor and the fourth capacitor respectively, then the Wheatstone bridge is formed jointly, the measurement precision of the MEMS pressure sensor is improved, meanwhile, the plane size of the MEMS pressure sensor is reduced, and the integration level of the device is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a MEMS pressure sensor, its manufacturing method, and an electronic device. Background Technology

[0002] MEMS pressure sensors represent a cutting-edge research field developed based on MEMS technology. They are suitable for harsh environments such as high impact, high overload, conductivity, corrosion, and radiation, and are widely used in aerospace, electronics, industry, medical and health, and environmental monitoring. Among them, capacitive pressure sensors have advantages such as high sensitivity, low power consumption, and good temperature characteristics compared to piezoresistive pressure sensors, and are therefore widely used in various fields.

[0003] Based on the capacitance formula, capacitive pressure sensors can be divided into three types: variable-gap, variable-area, and variable-dielectric. Due to their ease of implementation, variable-gap capacitive pressure sensors are the most common. Their principle is that changes in the spacing cause changes in capacitance, and the integrated circuit amplifies the signal. However, variable-gap capacitive pressure sensors in related technologies suffer from low measurement accuracy, hindering mass production applications, or excessively large planar dimensions leading to wasted device area and significantly increased costs. Summary of the Invention

[0004] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0005] To address the existing problems, this invention provides a method for manufacturing a MEMS pressure sensor, comprising:

[0006] A first substrate and a second substrate are provided, wherein a first pressure structure is formed on the first substrate and a second pressure structure is formed on the second substrate;

[0007] The first pressure structure and the second pressure structure are bonded together;

[0008] The first substrate is removed to expose the first pressure structure. The first pressure structure and the second pressure structure together constitute a third pressure structure. The third pressure structure includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer and a fifth electrode layer arranged from top to bottom. A dielectric layer is formed between adjacent electrode layers. A cavity penetrating the dielectric layer is formed in each dielectric layer.

[0009] In this configuration, all electrode layers except the second electrode layer have through holes that penetrate the electrode layer, or all electrode layers except the third electrode layer have through holes that penetrate the electrode layer, or all electrode layers except the fourth electrode layer have through holes that penetrate the electrode layer, and the cavity exposes the through holes.

[0010] The first electrode layer and the second electrode layer constitute a first capacitor, the second electrode layer and the third electrode layer constitute a second capacitor, the third electrode layer and the fourth electrode layer constitute a third capacitor, and the fourth capacitor layer and the fifth capacitor layer constitute a fourth capacitor. The first capacitor, the second capacitor, the third capacitor and the fourth capacitor together constitute a Wheatstone bridge.

[0011] For example, the dielectric layer is formed on the bonding surface of at least one of the first pressure structure and the second pressure structure, and the first pressure structure and the second pressure structure are bonded through the dielectric layer.

[0012] For example, the bonding is performed using a low-temperature vacuum bonding process.

[0013] For example, when through holes are formed in all electrode layers except the third electrode layer, the through holes in the first electrode layer and the through holes in the second electrode layer are arranged alternately.

[0014] When through holes are formed in all electrode layers except the fourth electrode layer, the through holes in the first electrode layer, the through holes in the second electrode layer, and the through holes in the third electrode layer are arranged alternately.

[0015] For example, the first pressure structure includes a first electrode layer and a second electrode layer, and the second pressure structure includes a third electrode layer, a fourth electrode layer and a fifth electrode layer. In the bonding step, the side of the first pressure structure in which the second electrode layer is formed and the side of the second pressure structure in which the third electrode layer is formed are bonded together. In this case, all electrode layers except the second electrode layer have through holes that penetrate the electrode layers.

[0016] For example, the first pressure structure includes a first electrode layer, a second electrode layer and a third electrode layer, and the second pressure structure includes a fourth electrode layer and a fifth electrode layer. In the bonding step, the side of the first pressure structure with the third electrode layer and the side of the second pressure structure with the fourth electrode layer are bonded together. In this case, all electrode layers except the third electrode layer have through holes that penetrate the electrode layers.

[0017] For example, the first pressure structure includes a first electrode layer, a second electrode layer, a third electrode layer, and a fourth electrode layer, and the second pressure structure includes a fifth electrode layer. In the bonding step, the side of the first pressure structure with the fourth electrode layer and the side of the second pressure structure with the fifth electrode layer are bonded together. In this case, all electrode layers except the third electrode layer have through holes that penetrate the electrode layers.

[0018] Another aspect of the present invention provides a MEMS pressure sensor, comprising:

[0019] Substrate;

[0020] A pressure structure, located on the substrate, includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer and a fifth electrode layer arranged from top to bottom, with a dielectric layer formed between adjacent electrode layers, and a cavity penetrating the dielectric layer is formed in each dielectric layer;

[0021] In this configuration, all electrode layers except the second electrode layer have through holes that penetrate the electrode layer, or all electrode layers except the third electrode layer have through holes that penetrate the electrode layer, or all electrode layers except the fourth electrode layer have through holes that penetrate the electrode layer, and the cavity exposes the through holes.

[0022] The first electrode layer and the second electrode layer constitute a first capacitor, the second electrode layer and the third electrode layer constitute a second capacitor, the third electrode layer and the fourth electrode layer constitute a third capacitor, and the fourth capacitor layer and the fifth capacitor layer constitute a fourth capacitor. The first capacitor, the second capacitor, the third capacitor and the fourth capacitor together constitute a Wheatstone bridge.

[0023] For example, when through holes are formed in all electrode layers except the third electrode layer, the through holes in the first electrode layer and the through holes in the second electrode layer are arranged alternately.

[0024] When through holes are formed in all electrode layers except the fourth electrode layer, the through holes in the first electrode layer, the through holes in the second electrode layer, and the through holes in the third electrode layer are arranged alternately.

[0025] In another aspect, the present invention provides an electronic device comprising the aforementioned MEMS pressure sensor.

[0026] The MEMS pressure sensor and its manufacturing method, as well as the electronic device, of this invention, obtain a third pressure structure by bonding a first pressure structure and a second pressure structure. The third pressure structure includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer, and a fifth electrode layer spaced apart from top to bottom. The first electrode layer and the second electrode layer constitute a first capacitor, the second electrode layer and the third electrode layer constitute a second capacitor, the third electrode layer and the fourth electrode layer constitute a third capacitor, and the fourth capacitor layer and the fifth capacitor layer constitute a fourth capacitor. The first capacitor, the second capacitor, the third capacitor, and the fourth capacitor together form a Wheatstone bridge, i.e., a vertically integrated Wheatstone bridge. This improves the measurement accuracy of the MEMS pressure sensor while reducing its planar size, thereby increasing the device's integration and reducing costs. Attached Figure Description

[0027] The following drawings, which are incorporated herein by reference as part of this invention, are provided for understanding the invention. The drawings illustrate embodiments of the invention and their descriptions, serving to explain the principles of the invention.

[0028] In the attached image:

[0029] Figure 1 A flowchart illustrating a method for manufacturing a MEMS pressure sensor according to an exemplary embodiment of the present invention is shown.

[0030] Figures 2A-2C A cross-sectional schematic diagram of the device obtained by sequentially implementing a method for manufacturing a MEMS pressure sensor according to an exemplary embodiment of the present invention is shown.

[0031] Figures 3A-3C A cross-sectional schematic diagram of a method for manufacturing a MEMS pressure sensor according to another exemplary embodiment of the present invention is shown, illustrating the device obtained by sequentially performing the manufacturing method.

[0032] Figures 4A-4C A cross-sectional schematic diagram of a device obtained by sequentially implementing a method for manufacturing a MEMS pressure sensor according to another exemplary embodiment of the present invention is shown.

[0033] Figure 5 The present invention is shown as follows Figure 2C A schematic diagram of the circuit structure of a Wheatstone bridge according to the exemplary embodiment shown. Detailed Implementation

[0034] The invention will now be described more fully with reference to the accompanying drawings, which illustrate embodiments of the invention. However, the invention can be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0035] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0036] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0037] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprise” and / or “comprising,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0038] To fully understand this invention, detailed steps and structures will be set forth in the following description to illustrate the technical solution proposed by this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0039] In related technologies, variable-pitch capacitive pressure sensors generally use a single-capacitor structure to measure pressure. However, the measurement accuracy of the single-capacitor structure is low, which is not conducive to mass production applications. In order to improve the measurement accuracy, a planar bridge capacitor structure is often used to measure pressure. However, the planar bridge capacitor structure will increase the planar size of the device, resulting in wasted area and increased manufacturing costs.

[0040] Therefore, in view of the aforementioned technical problems, this invention proposes a method for manufacturing a MEMS pressure sensor, such as... Figure 1 As shown, it mainly includes the following steps:

[0041] Step S1: Provide a first substrate and a second substrate, wherein a first pressure structure is formed on the first substrate and a second pressure structure is formed on the second substrate;

[0042] Step S2: Bond the first pressure structure and the second pressure structure together;

[0043] Step S3: Remove the first substrate to expose the first pressure structure. The first pressure structure and the second pressure structure together constitute the third pressure structure. The third pressure structure includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer, and a fifth electrode layer arranged from top to bottom. A dielectric layer is formed between adjacent electrode layers. A cavity penetrating the dielectric layer is formed in each dielectric layer.

[0044] In this configuration, all electrode layers except the second electrode layer have through holes that penetrate the electrode layer, or all electrode layers except the third electrode layer have through holes that penetrate the electrode layer, or all electrode layers except the fourth electrode layer have through holes that penetrate the electrode layer, and the cavity exposes the through holes.

[0045] The first electrode layer and the second electrode layer constitute a first capacitor, the second electrode layer and the third electrode layer constitute a second capacitor, the third electrode layer and the fourth electrode layer constitute a third capacitor, and the fourth capacitor layer and the fifth capacitor layer constitute a fourth capacitor. The first capacitor, the second capacitor, the third capacitor and the fourth capacitor together constitute a Wheatstone bridge.

[0046] The manufacturing method of the MEMS pressure sensor of the present invention obtains a third pressure structure by bonding a first pressure structure and a second pressure structure. The third pressure structure includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer, and a fifth electrode layer arranged from top to bottom. The first electrode layer and the second electrode layer constitute a first capacitor, the second electrode layer and the third electrode layer constitute a second capacitor, the third electrode layer and the fourth electrode layer constitute a third capacitor, and the fourth capacitor layer and the fifth capacitor layer constitute a fourth capacitor. The first capacitor, the second capacitor, the third capacitor, and the fourth capacitor together constitute a Wheatstone bridge, that is, a vertically integrated Wheatstone bridge. This improves the measurement accuracy of the MEMS pressure sensor while reducing its planar size, thereby improving the integration of the device and reducing the cost.

[0047] Example 1

[0048] Below, for reference Figure 1 , Figures 2A-2C , Figures 3A-3C , Figures 4A-4C as well as Figure 5 The method for manufacturing the MEMS pressure sensor of the present invention is described in detail, wherein, Figure 1 A flowchart illustrating a method for manufacturing a MEMS pressure sensor according to an exemplary embodiment of the present invention is shown. Figures 2A-2C The diagram shows a cross-sectional view of the device obtained by sequentially implementing a method for manufacturing a MEMS pressure sensor according to an exemplary embodiment of the present invention. Figures 3A-3C The diagram illustrates a cross-sectional view of a device obtained by sequentially implementing a method for manufacturing a MEMS pressure sensor according to another exemplary embodiment of the present invention. Figures 4A-4C This diagram illustrates a cross-sectional view of a device obtained by sequentially implementing a method for manufacturing a MEMS pressure sensor according to another exemplary embodiment of the present invention. Figure 5 The present invention is shown as follows Figure 2C A schematic diagram of the circuit structure of a Wheatstone bridge according to the exemplary embodiment shown.

[0049] Exemplarily, the method for manufacturing the MEMS pressure sensor of the present invention includes the following steps:

[0050] First, step S1 is performed, providing a first substrate and a second substrate, wherein a first pressure structure is formed on the first substrate and a second pressure structure is formed on the second substrate.

[0051] In one example, such as Figures 2A to 4C As shown, the first substrate 210 and the second substrate 220 are bulk silicon substrates, which can be at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP, InGaAs or other III / V compound semiconductors, including multilayer structures composed of these semiconductors, or silicon on insulator (SOI), silicon on insulator stacked on insulator (SSOI), silicon on insulator stacked on insulator (S-SiGeOI), silicon on insulator (SiGeOI), and germanium on insulator (GeOI), etc.

[0052] In one example, such as Figures 2A to 2C As shown, the first pressure structure includes a first electrode layer 211 and a second electrode layer 212, and the second pressure structure includes a third electrode layer 213, a fourth electrode layer 214, and a fifth electrode layer 215. The second electrode layer 212 is located on the first electrode layer 211, the fourth electrode layer 214 is located on the fifth electrode layer 215, and the third electrode layer 213 is located on the fourth electrode layer 214. Each electrode layer except the second electrode layer 212 has a through-hole 250 forming within it; that is, through-holes 250 are formed in the first electrode layer 211, the third electrode layer 213, the fourth electrode layer 214, and the fifth electrode layer 215. Exemplarily, a dielectric layer 230 is formed between adjacent electrode layers.

[0053] In one example, such as Figures 3A to 3C As shown, the first pressure structure includes a first electrode layer 211, a second electrode layer 212, and a third electrode layer 213, and the second pressure structure includes a fourth electrode layer 214 and a fifth electrode layer 215. The second electrode layer 212 is located on the first electrode layer 211, the third electrode layer 213 is located on the second electrode layer 212, and the fourth electrode layer 214 is located on the fifth electrode layer 215. Except for the third electrode layer 213, each electrode layer has a through-hole 250, meaning that through-holes 250 are formed in the first electrode layer 211, the second electrode layer 212, the fourth electrode layer 214, and the fifth electrode layer 215.

[0054] In one example, such as Figures 4A to 4CAs shown, the first pressure structure includes a first electrode layer 211, a second electrode layer 212, a third electrode layer 213, and a fourth electrode layer 214, and the second pressure structure includes a fifth electrode layer 215. The second electrode layer 212 is located on the first electrode layer 211, the third electrode layer 213 is located on the second electrode layer 212, and the fourth electrode layer 214 is located on the third electrode layer 213. Except for the fourth electrode layer 214, each electrode layer has a through-hole 250, meaning that through-holes 250 are formed in the first electrode layer 211, the second electrode layer 212, the third electrode layer 213, and the fifth electrode layer 215.

[0055] In one example, the first electrode layer 211, the second electrode layer 212, the third electrode layer 213, the fourth electrode layer 214, and the fifth electrode layer 215 can be made of materials such as doped polycrystalline silicon, SiGe, or implanted and annealed amorphous silicon, and are not limited to any one of them. The first electrode layer 211 can be formed by chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD), or it can be formed by furnace tube growth or selective epitaxial growth (SEG). This application does not impose any limitations on this method.

[0056] In one example, the dielectric layer 230 serves a supporting function, which can be used to improve the strength of the device. Exemplarily, the dielectric layer 230 can be an oxide layer, such as silicon oxide and silicon carbon-doped oxide (SiOC), but is not limited to the examples described above. Furthermore, the dielectric layer 230 can be formed using various deposition methods commonly used in the art, such as plasma-enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), physical vapor deposition, or atomic layer deposition (ALD).

[0057] Next, step S2 is performed to bond the first pressure structure and the second pressure structure.

[0058] In one example, such as Figure 2C As shown, when the first pressure structure includes a first electrode layer 211 and a second electrode layer 212, and the second pressure structure includes a third electrode layer 213, a fourth electrode layer 214 and a fifth electrode layer 215, the side of the first pressure structure with the second electrode layer 212 formed is bonded to the side of the second pressure structure with the third electrode layer 213 formed in the bonding step.

[0059] In one example, such as Figure 3CAs shown, when the first pressure structure includes a first electrode layer 211, a second electrode layer 212 and a third electrode layer 213, and the second pressure structure includes a fourth electrode layer 214 and a fifth electrode layer 215, in the bonding step, the side of the first pressure structure in which the third electrode layer 213 is formed is bonded to the side of the second pressure structure in which the fourth electrode layer 214 is formed.

[0060] In one example, such as Figure 4C As shown, when the first pressure structure includes a first electrode layer 211, a second electrode layer 212, a third electrode layer 213 and a fourth electrode layer 214, and the second pressure structure includes a fifth electrode layer 215, the side of the first pressure structure with the fourth electrode layer 214 formed is bonded to the side of the second pressure structure with the fifth electrode layer 215 formed in the bonding step.

[0061] In one example, a low-temperature vacuum bonding process is used to perform the above bonding steps. Exemplarily, after the low-temperature vacuum bonding, a low-temperature annealing process is then performed. Exemplarily, the temperature of the low-temperature bonding process is below 450 degrees Celsius.

[0062] In one example, such as Figures 2A to 4C As shown, a dielectric layer 230 is formed on the bonding surface of at least one of the first pressure structure and the second pressure structure, and the first pressure structure and the second pressure structure are bonded through the dielectric layer. Exemplarily, the accompanying drawings of this application show that the dielectric layer 230 is formed on the bonding surfaces of both the first pressure structure and the second pressure structure. In other embodiments, the dielectric layer 230 may be formed only on the bonding surface of the first pressure structure, or only on the bonding surface of the second pressure structure.

[0063] Finally, step S3 is executed to remove the first substrate to expose the first pressure structure. The first pressure structure and the second pressure structure together constitute the third pressure structure. The third pressure structure includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer, and a fifth electrode layer arranged from top to bottom. A dielectric layer is formed between adjacent electrode layers, and a cavity penetrating the dielectric layer is formed in each dielectric layer.

[0064] In one example, such as Figure 2C , Figure 3C and Figure 4C As shown, the first substrate 210 needs to be removed after the bonding step to expose the first pressure structure. Exemplarily, conventional thinning and etching processes can be used to remove the first substrate 210.

[0065] In one example, such as Figures 2A to 4CAs shown, interconnecting layers may be formed between the first substrate 210 and the electrode layer, and between the second substrate 220 and the electrode layer. The material of this interconnecting layer may include any of several dielectric materials, with non-limiting examples including oxides, nitrides, and oxide oxynitrides, particularly oxides, nitrides, and oxides of silicon, but excluding oxides, nitrides, and oxides of other elements. This interconnecting layer can be formed using any of several methods, with non-limiting examples including ion implantation, thermal oxidation or plasma oxidation or thermal nitriding or plasma nitriding, plasma-enhanced chemical vapor deposition, low-pressure chemical vapor deposition, and physical vapor deposition. Exemplarily, when an interconnecting layer is also formed between the first substrate 210 and the electrode layer, a portion of the interconnecting layer should be removed when the first substrate 210 is removed to expose the via 250.

[0066] In one example, the via 250 can be formed using etching processes commonly used in the art, such as dry etching or wet etching. More specifically, buffered oxide etchants or gaseous hydrogen fluoride (VHF) can be used.

[0067] In one example, cavity 240 is obtained by removing a portion of dielectric layer 230 through via 250. Exemplarily, etching processes commonly used in the art can be employed to remove the portion of dielectric layer 230. For example, wet etching can be used, more specifically, buffer oxide etchant can be used, or gaseous hydrogen fluoride (VHF) can be used. Exemplarily, the release boundary range of dielectric layer 230 can be reasonably set according to actual needs, wherein the release boundary refers to the width of the remaining dielectric layer 230.

[0068] In one example, the cavity 240 and the through-hole 250 in the second pressure structure should be formed before the bonding step. In another example, the cavity 240 and the through-hole 250 in the first pressure structure can be formed before or after the bonding step. For example, the through-hole 250 can be formed first, then bonding can be performed, and then the cavity 240 can be formed; or the through-hole 250 and the cavity 240 can be formed first, and then bonding can be performed; or the bonding can be performed first, and then the through-hole 250 and the cavity 240 can be formed.

[0069] In one example, such as Figure 3C and Figure 4CAs shown, when through-holes 250 are formed in all electrode layers except the third electrode layer 213, the through-holes 250 in the first electrode layer 211 and the through-holes 250 in the second electrode layer 212 are staggered; when through-holes 250 are formed in all electrode layers except the fourth electrode layer 214, the through-holes 250 in the first electrode layer 211, the through-holes 250 in the second electrode layer 212, and the through-holes 250 in the third electrode layer 213 are staggered. For example, the staggered arrangement here refers to the fact that the positions of the through-holes are not one-to-one. For example, when through-holes 250 are formed in all electrode layers except the third electrode layer 213, the first electrode layer 211 and the second electrode layer 212 are in direct contact with the external environment. By staggering the through-holes 250 in the first electrode layer 211 and the second electrode layer 212, foreign objects from the external environment can be effectively prevented from entering the device and causing a decrease in device performance. Similarly, when through-holes 250 are formed in all electrode layers except the fourth electrode layer 214, the first electrode layer 211, the second electrode layer 212, and the third electrode layer 213 are in direct contact with the external environment. By staggering the through-holes 250 in the first electrode layer 211, the second electrode layer 212, and the third electrode layer 213, foreign objects from the external environment can be effectively prevented from entering the device and causing a decrease in device performance.

[0070] In one example, such as Figure 2C , Figure 3C and Figure 4C As shown, the first electrode layer 211 and the second electrode layer 212 constitute the first capacitor C1, the second electrode layer 212 and the third electrode layer 213 constitute the second capacitor C2, the third electrode layer 213 and the fourth electrode layer 214 constitute the third capacitor C3, and the fourth electrode layer 214 and the fifth electrode layer 215 constitute the fourth capacitor C4. The first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 together form... Figure 5 The Wheatstone bridge shown. Exemplarily, because the first electrode layer 211, second electrode layer 212, third electrode layer 213, fourth electrode layer 214, and fifth electrode layer 215 are spaced apart from top to bottom, the first capacitor C1, second capacitor C2, third capacitor C3, and fourth capacitor C4 are also arranged vertically, which can greatly reduce the planar size of the MEMS pressure sensor, improve the device integration, and thus reduce the device cost. Exemplarily, as... Figure 5The positions of the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 in the Wheatstone bridge shown are merely illustrative. In other embodiments, the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 can also be configured into a Wheatstone bridge through other connection methods. For example, the first capacitor C1 and the fourth capacitor C4 may be located on the same bridge arm, and the second capacitor C2 and the third capacitor C3 may be located on the same bridge arm. This application does not impose any limitations on this.

[0071] For example, such as Figure 2C As shown, the first capacitor C1, formed by the first electrode layer 211 and the second electrode layer 212, is a variable capacitor. When subjected to external pressure, the second electrode layer 212 deforms, increasing the distance between the first electrode layer 211 and the second electrode layer 212, thereby reducing the capacitance of the first capacitor C1. The second capacitor C2, formed by the second electrode layer 212 and the third electrode layer 213, is also a variable capacitor. When subjected to external pressure, the second electrode layer 212 deforms, decreasing the distance between the third electrode layer 213 and the second electrode layer 212, thereby increasing the capacitance of the second capacitor C2. The third capacitor C3, formed by the third electrode layer 213 and the fourth electrode layer 214, and the fourth capacitor C4, formed by the fourth electrode layer 214 and the fifth electrode layer 215, are both fixed reference capacitors. When subjected to external pressure, the capacitances of the third capacitor C3 and the fourth capacitor C4 remain unchanged.

[0072] In another example, such as Figure 3C As shown, the second capacitor C2, formed by the second electrode layer 212 and the third electrode layer 213, is a variable capacitor. When subjected to external pressure, the third electrode layer 213 deforms, increasing the distance between the second electrode layer 212 and the third electrode layer 213, thereby reducing the capacitance of the second capacitor C2. The third capacitor C3, formed by the third electrode layer 213 and the fourth electrode layer 214, is also a variable capacitor. When subjected to external pressure, the third electrode layer 213 deforms, decreasing the distance between the fourth electrode layer 214 and the third electrode layer 213, thereby increasing the capacitance of the third capacitor C3. The first capacitor C1, formed by the first electrode layer 211 and the second electrode layer 212, and the fourth capacitor C4, formed by the fourth electrode layer 214 and the fifth electrode layer 215, are both fixed reference capacitors. When subjected to external pressure, the capacitances of the first capacitor C1 and the fourth capacitor C4 remain unchanged.

[0073] In another example, such as Figure 4CAs shown, the third capacitor C3, formed by the third electrode layer 213 and the fourth electrode layer 214, is a variable capacitor. When subjected to external pressure, the fourth electrode layer 214 deforms, increasing the distance between the third electrode layer 213 and the fourth electrode layer 214, thereby reducing the capacitance of the third capacitor C3. The fourth capacitor C4, formed by the fourth electrode layer 214 and the fifth electrode layer 215, is also a variable capacitor. When subjected to external pressure, the fourth electrode layer 214 deforms, decreasing the distance between the fifth electrode layer 215 and the fourth electrode layer 214, thereby increasing the capacitance of the fourth capacitor C4. The first capacitor C1, formed by the first electrode layer 211 and the second electrode layer 212, and the second capacitor C2, formed by the second electrode layer 212 and the third electrode layer 213, are both fixed reference capacitors. When subjected to external pressure, the capacitances of the first capacitor C1 and the second capacitor C2 remain unchanged.

[0074] In one example, with Figure 2C The device structure shown and Figure 5 Taking the Wheatstone bridge structure shown as an example, one arm of the Wheatstone bridge has a first capacitor C1 and a third capacitor C3, while the other arm has a second capacitor C2 and a fourth capacitor C4. The first and second capacitors C1 and C2 are variable capacitors, while the third and fourth capacitors C3 and C4 are fixed reference capacitors. When subjected to external pressure, the capacitances of both capacitors C1 and C2 change, causing a change in the output voltage between V+ and V-. By measuring the output voltage, the change in capacitance of capacitors C1 and C2 can be obtained, and thus the corresponding pressure value can be determined, completing the pressure measurement. For example, compared to measuring pressure using a single capacitor structure, measuring pressure using a Wheatstone bridge, due to the differential output, offers higher measurement accuracy and effectively cancels common-mode noise interference. For example, the initial capacitances of the first capacitor C1, second capacitor C2, third capacitor C3, and fourth capacitor C4 can be set to be equal when no pressure is applied. In this case, the Wheatstone bridge is in a balanced state when no pressure is applied. When pressure is applied, the Wheatstone bridge becomes unbalanced, and the change in output voltage is easier to measure. Furthermore, the changes in capacitance of two of the variable capacitors in the first capacitor C1, second capacitor C2, third capacitor C3, and fourth capacitor C4 can be made equal when pressure is applied; in this case, the change in output voltage is also easier to measure.

[0075] It is worth mentioning that the above steps are only examples, and the order of the steps can be adjusted without conflict.

[0076] This concludes the description of the key steps in the manufacturing method of the MEMS pressure sensor of the present invention. The manufacturing of a complete MEMS pressure sensor may also include other steps, such as the step of forming the pads of the lead-out electrode layer, which will not be described in detail here.

[0077] In summary, the manufacturing method of the MEMS pressure sensor of the present invention obtains a third pressure structure by bonding a first pressure structure and a second pressure structure. The third pressure structure includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer, and a fifth electrode layer arranged from top to bottom. The first electrode layer and the second electrode layer constitute a first capacitor, the second electrode layer and the third electrode layer constitute a second capacitor, the third electrode layer and the fourth electrode layer constitute a third capacitor, and the fourth capacitor layer and the fifth capacitor layer constitute a fourth capacitor. The first capacitor, the second capacitor, the third capacitor, and the fourth capacitor together constitute a Wheatstone bridge, that is, a vertically integrated Wheatstone bridge. This improves the measurement accuracy of the MEMS pressure sensor while reducing its planar size, thereby improving the integration of the device and reducing the cost.

[0078] Example 2

[0079] The present invention also provides a MEMS pressure sensor, which is described below with reference to... Figure 2C , Figure 3C , Figure 4C and Figure 5 To describe an exemplary embodiment of the present invention, a MEMS pressure sensor is provided, which is manufactured by the method described in the first embodiment. The MEMS pressure sensor of the present invention includes:

[0080] Substrate 220;

[0081] The pressure structure, located on the substrate 200, includes a first electrode layer 211, a second electrode layer 212, a third electrode layer 213, a fourth electrode layer 214 and a fifth electrode layer 215 arranged from top to bottom. A dielectric layer 230 is formed between adjacent electrode layers, and a cavity 240 penetrating the dielectric layer 230 is formed in each dielectric layer 230.

[0082] In this process, through holes 250 are formed in all electrode layers except the second electrode layer 212, or through holes 250 are formed in all electrode layers except the third electrode layer 213, or through holes 250 are formed in all electrode layers except the fourth electrode layer 214, and the cavity 240 exposes the through holes 250.

[0083] The first electrode layer 211 and the second electrode layer 212 constitute the first capacitor, the second electrode layer 212 and the third electrode layer 213 constitute the second capacitor, the third electrode layer 213 and the fourth electrode layer 214 constitute the third capacitor, the fourth capacitor layer 214 and the fifth capacitor layer 215 constitute the fourth capacitor, and the first capacitor, the second capacitor, the third capacitor and the fourth capacitor together constitute a Wheatstone bridge.

[0084] In one example, the substrate 220 is a bulk silicon substrate, which may be at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP, InGaAs, or other III / V compound semiconductors, including multilayer structures composed of these semiconductors, or silicon-on-insulator (SOI), silicon-on-insulator stacked (SSOI), silicon-on-insulator stacked (S-SiGeOI), silicon-on-insulator (SiGeOI), and germanium-on-insulator (GeOI), etc.

[0085] In one example, such as Figure 3C and Figure 4C As shown, when through-holes 250 are formed in all electrode layers except the third electrode layer 213, the through-holes 250 in the first electrode layer 211 and the through-holes 250 in the second electrode layer 212 are staggered; when through-holes 250 are formed in all electrode layers except the fourth electrode layer 214, the through-holes 250 in the first electrode layer 211, the through-holes 250 in the second electrode layer 212, and the through-holes 250 in the third electrode layer 213 are staggered. For example, the staggered arrangement here refers to the fact that the positions of the through-holes are not one-to-one. For example, when through-holes 250 are formed in all electrode layers except the third electrode layer 213, the first electrode layer 211 and the second electrode layer 212 are in direct contact with the external environment. By staggering the through-holes 250 in the first electrode layer 211 and the second electrode layer 212, foreign objects from the external environment can be effectively prevented from entering the device and causing a decrease in device performance. Similarly, when through-holes 250 are formed in all electrode layers except the fourth electrode layer 214, the first electrode layer 211, the second electrode layer 212, and the third electrode layer 213 are in direct contact with the external environment. By staggering the through-holes 250 in the first electrode layer 211, the second electrode layer 212, and the third electrode layer 213, foreign objects from the external environment can be effectively prevented from entering the device and causing a decrease in device performance.

[0086] In one example, such as Figure 2C , Figure 3C and Figure 4CAs shown, the first electrode layer 211 and the second electrode layer 212 constitute the first capacitor C1, the second electrode layer 212 and the third electrode layer 213 constitute the second capacitor C2, the third electrode layer 213 and the fourth electrode layer 214 constitute the third capacitor C3, and the fourth electrode layer 214 and the fifth electrode layer 215 constitute the fourth capacitor C4. The first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 together form... Figure 5 The Wheatstone bridge shown. Exemplarily, because the first electrode layer 211, second electrode layer 212, third electrode layer 213, fourth electrode layer 214, and fifth electrode layer 215 are spaced apart from top to bottom, the first capacitor C1, second capacitor C2, third capacitor C3, and fourth capacitor C4 are also arranged vertically, which can greatly reduce the planar size of the MEMS pressure sensor, improve the device integration, and thus reduce the device cost. Exemplarily, as... Figure 5 The positions of the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 in the Wheatstone bridge shown are merely illustrative. In other embodiments, the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 can also be configured into a Wheatstone bridge through other connection methods. For example, the first capacitor C1 and the fourth capacitor C4 may be located on the same bridge arm, and the second capacitor C2 and the third capacitor C3 may be located on the same bridge arm. This application does not impose any limitations on this.

[0087] In one example, such as Figure 2C As shown, the first capacitor C1, formed by the first electrode layer 211 and the second electrode layer 212, is a variable capacitor. When subjected to external pressure, the second electrode layer 212 deforms, increasing the distance between the first electrode layer 211 and the second electrode layer 212, thereby reducing the capacitance of the first capacitor C1. The second capacitor C2, formed by the second electrode layer 212 and the third electrode layer 213, is also a variable capacitor. When subjected to external pressure, the second electrode layer 212 deforms, decreasing the distance between the third electrode layer 213 and the second electrode layer 212, thereby increasing the capacitance of the second capacitor C2. The third capacitor C3, formed by the third electrode layer 213 and the fourth electrode layer 214, and the fourth capacitor C4, formed by the fourth electrode layer 214 and the fifth electrode layer 215, are both fixed reference capacitors. When subjected to external pressure, the capacitances of the third capacitor C3 and the fourth capacitor C4 remain unchanged.

[0088] In another example, such as Figure 3CAs shown, the second capacitor C2, formed by the second electrode layer 212 and the third electrode layer 213, is a variable capacitor. When subjected to external pressure, the third electrode layer 213 deforms, increasing the distance between the second electrode layer 212 and the third electrode layer 213, thereby reducing the capacitance of the second capacitor C2. The third capacitor C3, formed by the third electrode layer 213 and the fourth electrode layer 214, is also a variable capacitor. When subjected to external pressure, the third electrode layer 213 deforms, decreasing the distance between the fourth electrode layer 214 and the third electrode layer 213, thereby increasing the capacitance of the third capacitor C3. The first capacitor C1, formed by the first electrode layer 211 and the second electrode layer 212, and the fourth capacitor C4, formed by the fourth electrode layer 214 and the fifth electrode layer 215, are both fixed reference capacitors. When subjected to external pressure, the capacitances of the first capacitor C1 and the fourth capacitor C4 remain unchanged.

[0089] In another example, such as Figure 4C As shown, the third capacitor C3, formed by the third electrode layer 213 and the fourth electrode layer 214, is a variable capacitor. When subjected to external pressure, the fourth electrode layer 214 deforms, increasing the distance between the third electrode layer 213 and the fourth electrode layer 214, thereby reducing the capacitance of the third capacitor C3. The fourth capacitor C4, formed by the fourth electrode layer 214 and the fifth electrode layer 215, is also a variable capacitor. When subjected to external pressure, the fourth electrode layer 214 deforms, decreasing the distance between the fifth electrode layer 215 and the fourth electrode layer 214, thereby increasing the capacitance of the fourth capacitor C4. The first capacitor C1, formed by the first electrode layer 211 and the second electrode layer 212, and the second capacitor C2, formed by the second electrode layer 212 and the third electrode layer 213, are both fixed reference capacitors. When subjected to external pressure, the capacitances of the first capacitor C1 and the second capacitor C2 remain unchanged.

[0090] In one example, with Figure 2C The device structure shown and Figure 5Taking the Wheatstone bridge structure shown as an example, one arm of the Wheatstone bridge has a first capacitor C1 and a third capacitor C3, while the other arm has a second capacitor C2 and a fourth capacitor C4. The first and second capacitors C1 and C2 are variable capacitors, while the third and fourth capacitors C3 and C4 are fixed reference capacitors. When subjected to external pressure, the capacitances of both capacitors C1 and C2 change, causing a change in the output voltage between V+ and V-. By measuring the output voltage, the change in capacitance of capacitors C1 and C2 can be obtained, and thus the corresponding pressure value can be determined, completing the pressure measurement. For example, compared to measuring pressure using a single capacitor structure, measuring pressure using a Wheatstone bridge, due to the differential output, offers higher measurement accuracy and effectively cancels common-mode noise interference. For example, the initial capacitances of the first capacitor C1, second capacitor C2, third capacitor C3, and fourth capacitor C4 can be set to be equal when no pressure is applied. In this case, the Wheatstone bridge is in a balanced state when no pressure is applied. When pressure is applied, the Wheatstone bridge becomes unbalanced, and the change in output voltage is easier to measure. Furthermore, the changes in capacitance of two of the variable capacitors in the first capacitor C1, second capacitor C2, third capacitor C3, and fourth capacitor C4 can be made equal when pressure is applied; in this case, the change in output voltage is also easier to measure.

[0091] This concludes the introduction to the structure of the MEMS pressure sensor of the present invention. The complete device may also include other components, such as pads for leading out the electrode layer, which will not be described in detail here.

[0092] Because the MEMS pressure sensor of the present invention has a pressure structure, the pressure structure includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer and a fifth electrode layer arranged from top to bottom. The first electrode layer and the second electrode layer constitute a first capacitor, the second electrode layer and the third electrode layer constitute a second capacitor, the third electrode layer and the fourth electrode layer constitute a third capacitor, and the fourth capacitor layer and the fifth capacitor layer constitute a fourth capacitor. The first capacitor, the second capacitor, the third capacitor and the fourth capacitor together constitute a Wheatstone bridge, that is, a vertically integrated Wheatstone bridge. This improves the measurement accuracy of the MEMS pressure sensor while reducing its planar size, thereby improving the integration of the device and reducing the cost.

[0093] Example 3

[0094] The present invention also provides an electronic device comprising the MEMS pressure sensor described in Embodiment 2 or the MEMS pressure sensor manufactured by the method described in Embodiment 1.

[0095] The electronic device can be any electronic product or device such as a mobile phone, tablet computer, laptop computer, netbook, game console, television, VCD player, DVD player, navigator, camera, camcorder, voice recorder, MP3 player, MP4 player, PSP, etc., or it can be an intermediate product with the aforementioned MEMS pressure sensor, such as a mobile phone motherboard with the integrated circuit. The electronic device of this embodiment of the invention has better performance because it uses the aforementioned MEMS pressure sensor.

[0096] Although several embodiments have been described herein, it should be understood that many other modifications and embodiments will be conceived by those skilled in the art, all of which will fall within the spirit and scope of the disclosed concept. More particularly, various modifications and changes can be made in terms of the arrangement and / or components of the subject matter within the scope of the disclosure, drawings, and appended claims. In addition to modifications and changes in components and / or arrangement, the use of alternative methods will also be obvious to those skilled in the art.

Claims

1. A method for manufacturing a MEMS pressure sensor, characterized in that, The method includes: A first substrate and a second substrate are provided, wherein a first pressure structure is formed on the first substrate and a second pressure structure is formed on the second substrate; The first pressure structure and the second pressure structure are bonded together; The first substrate is removed to expose the first pressure structure. The first pressure structure and the second pressure structure together constitute a third pressure structure. The third pressure structure includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer and a fifth electrode layer arranged from top to bottom. A dielectric layer is formed between adjacent electrode layers. A cavity penetrating the dielectric layer is formed in each dielectric layer. In this configuration, all electrode layers except the second electrode layer have through holes that penetrate the electrode layer, or all electrode layers except the third electrode layer have through holes that penetrate the electrode layer, or all electrode layers except the fourth electrode layer have through holes that penetrate the electrode layer, and the cavity exposes the through holes. The first electrode layer and the second electrode layer constitute a first capacitor, the second electrode layer and the third electrode layer constitute a second capacitor, the third electrode layer and the fourth electrode layer constitute a third capacitor, and the fourth capacitor layer and the fifth capacitor layer constitute a fourth capacitor. The first capacitor, the second capacitor, the third capacitor and the fourth capacitor together constitute a Wheatstone bridge.

2. The manufacturing method according to claim 1, characterized in that, The dielectric layer is formed on the bonding surface of at least one of the first pressure structure and the second pressure structure, and the first pressure structure and the second pressure structure are bonded through the dielectric layer.

3. The manufacturing method according to claim 1, characterized in that, The bonding is performed using a low-temperature vacuum bonding process.

4. The manufacturing method according to claim 1, characterized in that, When through holes are formed in all electrode layers except the third electrode layer, the through holes in the first electrode layer and the through holes in the second electrode layer are arranged alternately. When through holes are formed in all electrode layers except the fourth electrode layer, the through holes in the first electrode layer, the through holes in the second electrode layer, and the through holes in the third electrode layer are arranged alternately.

5. The manufacturing method according to claim 1, characterized in that, The first pressure structure includes a first electrode layer and a second electrode layer, and the second pressure structure includes a third electrode layer, a fourth electrode layer and a fifth electrode layer. In the bonding step, the side of the first pressure structure with the second electrode layer and the side of the second pressure structure with the third electrode layer are bonded together. In this case, all electrode layers except the second electrode layer have through holes that penetrate the electrode layers.

6. The manufacturing method according to claim 1, characterized in that, The first pressure structure includes a first electrode layer, a second electrode layer, and a third electrode layer. The second pressure structure includes a fourth electrode layer and a fifth electrode layer. In the bonding step, the side of the first pressure structure with the third electrode layer and the side of the second pressure structure with the fourth electrode layer are bonded together. In this case, all electrode layers except the third electrode layer have through holes that penetrate the electrode layers.

7. The manufacturing method according to claim 1, characterized in that, The first pressure structure includes a first electrode layer, a second electrode layer, a third electrode layer, and a fourth electrode layer. The second pressure structure includes a fifth electrode layer. In the bonding step, the side of the first pressure structure with the fourth electrode layer and the side of the second pressure structure with the fifth electrode layer are bonded together. In this case, all electrode layers except the third electrode layer have through holes that penetrate the electrode layers.

8. A MEMS pressure sensor, characterized in that, include: Substrate; A pressure structure, located on the substrate, includes a first electrode layer, a second electrode layer, a third electrode layer, a fourth electrode layer and a fifth electrode layer arranged from top to bottom, with a dielectric layer formed between adjacent electrode layers, and a cavity penetrating the dielectric layer is formed in each dielectric layer; In this configuration, all electrode layers except the second electrode layer have through holes that penetrate the electrode layer, or all electrode layers except the third electrode layer have through holes that penetrate the electrode layer, or all electrode layers except the fourth electrode layer have through holes that penetrate the electrode layer, and the cavity exposes the through holes. The first electrode layer and the second electrode layer constitute a first capacitor, the second electrode layer and the third electrode layer constitute a second capacitor, the third electrode layer and the fourth electrode layer constitute a third capacitor, and the fourth capacitor layer and the fifth capacitor layer constitute a fourth capacitor. The first capacitor, the second capacitor, the third capacitor and the fourth capacitor together constitute a Wheatstone bridge.

9. The MEMS pressure sensor according to claim 8, characterized in that, When through holes are formed in all electrode layers except the third electrode layer, the through holes in the first electrode layer and the through holes in the second electrode layer are arranged alternately. When through holes are formed in all electrode layers except the fourth electrode layer, the through holes in the first electrode layer, the through holes in the second electrode layer, and the through holes in the third electrode layer are arranged alternately.

10. An electronic device, characterized in that, The electronic device includes the MEMS pressure sensor according to any one of claims 8-9.

Images