Capacitive pressure sensor and method of manufacturing the same

Abstract

This application discloses a capacitive pressure sensor and its manufacturing method. The capacitive pressure sensor includes a plurality of capacitive pressure sensor cells, each cell comprising: a support structure, a detection capacitor, and a reference capacitor located on the same substrate. The support structure includes a first support structure, a second support structure, and a third support structure. The first and second support structures surround the detection capacitor, and the second and third support structures surround the reference capacitor. The upper and lower electrodes of the detection capacitor, the upper electrode of the reference capacitor, and the lower electrode of the reference capacitor are physically independent of each other. In this application, the detection capacitor and the reference capacitor are on the same substrate, simplifying the manufacturing process. Furthermore, the physical independence of the upper and lower electrodes of the detection capacitor and the reference capacitor prevents mutual interference and malfunctions, thereby improving the sensitivity of the capacitive pressure sensor.

Description

Technical Field

[0001] This application relates to the field of semiconductor device manufacturing, and more specifically, to a capacitive pressure sensor and a method for manufacturing the same. Background Technology

[0002] In recent years, capacitive pressure sensors have been widely used in consumer electronics, automotive systems, environmental monitoring, medical diagnostics, aerospace, and other fields. Capacitive pressure sensors can be classified according to their operating principle into strain gauge, piezoresistive, piezoelectric, frequency-resonance, and capacitive pressure sensors. MEMS capacitive pressure sensors typically consist of a pressure-sensitive movable electrode and a fixed electrode. Reducing the distance between the movable and fixed electrodes can effectively improve the sensitivity of the capacitive pressure sensor.

[0003] The electrode spacing of a MEMS capacitive pressure sensor is typically determined by the thickness of the sacrificial layer between them. However, as the thickness of the sacrificial layer decreases, the difficulty of releasing the sacrificial layer also increases significantly. Summary of the Invention

[0004] In view of this, this application provides a capacitive pressure sensor and a method for manufacturing the same, thereby solving the above-mentioned problems.

[0005] According to one aspect of this application, a capacitive pressure sensor is provided, comprising a plurality of capacitive pressure sensor cells, wherein the capacitive pressure sensor cells include:

[0006] The support structure, the detection capacitor, and the reference capacitor are located on the same substrate.

[0007] The support structure includes a first support structure, a second support structure, and a third support structure. The first support structure and the second support structure surround the detection capacitor, and the second support structure and the third support structure surround the reference capacitor. The upper plate of the detection capacitor, the lower plate of the detection capacitor, the upper plate of the reference capacitor, and the lower plate of the reference capacitor are physically independent of each other.

[0008] Optionally, it also includes:

[0009] Substrate;

[0010] An insulating layer located on the substrate;

[0011] A stop layer, the stop layer being located on the insulating layer;

[0012] A first conductive layer, comprising a first conductive region, a second conductive region, and a third conductive region that are independent of each other;

[0013] The second conductive layer includes a fourth conductive region, a fifth conductive region, and a sixth conductive region that are independent of each other;

[0014] The third conductive layer includes a seventh conductive region, an eighth conductive region, and a ninth conductive region;

[0015] The first conductive region is electrically connected to the fourth conductive region and serves as the lower electrode of the detection capacitor; the seventh conductive region serves as the upper electrode of the detection capacitor, and a first cavity is formed between the seventh conductive region, the fourth conductive region, and the first conductive region.

[0016] The second conductive region is electrically connected to the fifth conductive region and serves as the lower electrode of the reference capacitor; the eighth conductive region serves as the upper electrode of the reference capacitor, and a second cavity is formed between the eighth conductive region, the fifth conductive region, and the second conductive region.

[0017] The third conductive region, a portion of the sixth conductive region, and the ninth conductive region are electrically connected and serve as the supporting structure.

[0018] Optionally, the third conductive layer in the first support structure and the second support structure are connected, the third conductive layer in the second support structure and the third support structure are connected, and the seventh conductive region is movable.

[0019] Optionally, the second support structure is an integral structure.

[0020] Optionally, the second support structure comprises at least two parts, and the ninth conductive region of each part is separated from each other.

[0021] Optionally, it also includes:

[0022] A plurality of first release paths, the first release paths extending through a portion of the fourth conductive region, the first release paths communicating with the first cavity and / or the second cavity to release the sacrificial layer;

[0023] Several second release paths, each second release path penetrating a portion of the fifth conductive region in the reference capacitor, the second release path communicating with the first cavity and / or the second cavity to release the sacrificial layer.

[0024] Optionally, it also includes:

[0025] The first conductive region and the fourth conductive region are connected by a first connecting structure. The width of the first connecting structure is smaller than the width of the fourth conductive region after it is connected. A seventh release path is formed between adjacent first connecting structures.

[0026] The second conductive region and the fifth conductive region are connected by a second connecting structure. The width of the second connecting structure is smaller than the width of the fifth conductive region after it is connected. An eighth release path is formed between adjacent second connecting structures.

[0027] Optionally, it also includes:

[0028] A third release path extends through a portion of the third conductive region, the sixth conductive region, and the ninth conductive region in at least one support structure, and communicates with the first cavity and / or the second cavity to release the sacrificial layer in the capacitive pressure sensor.

[0029] Optionally, the three release paths include a fourth release path and a fifth release path. The fourth release path is located in the first support structure, and the fifth release path is located in the third support structure. The ninth conductive region forming the fourth release path has a first release hole communicating with the fourth release path, and the ninth conductive region forming the fifth release path has a second release hole communicating with the fifth release path.

[0030] Optionally, the third release path further includes a sixth release path, the sixth release path being located in the second support structure, and the ninth conductive region forming the sixth release path having a third release hole communicating with the sixth release path.

[0031] Optionally, it also includes:

[0032] A sealing layer located above the third conductive layer, the sealing layer including an opening corresponding to the seventh conductive region of the third conductive layer, and a peripheral portion surrounding the opening.

[0033] The opening in the sealing layer allows the seventh conductive region to move in the vertical direction, while the peripheral portion of the sealing layer restricts the movement of the eighth and ninth conductive regions in the vertical direction.

[0034] Optionally, it also includes:

[0035] A passivation layer located above the sealing layer.

[0036] Optionally, it also includes:

[0037] A first sacrificial layer is located between the first conductive layer and the second conductive layer, and at least a portion of the first sacrificial layer is removed to form the fourth, fifth, seventh, and eighth release pathways between the first and second conductive layers.

[0038] Optionally, it also includes:

[0039] A second sacrificial layer and a third sacrificial layer are located between the second conductive layer and the third conductive layer, and at least a portion of the second sacrificial layer and the third sacrificial layer are removed to form the first cavity and the second cavity.

[0040] Optionally, the seventh conductive region and the eighth conductive region are connected to the ninth conductive region in the second support structure, the seventh conductive region is also connected to the first support structure, and the eighth conductive region is also connected to the third support structure.

[0041] Optionally, it also includes:

[0042] The first conductive contact is connected to either the first support structure or the third support structure.

[0043] Optionally, it also includes:

[0044] The second conductive contact is connected to the first conductive area;

[0045] The third conductive contact is connected to the second conductive area.

[0046] Optionally, the capacitive pressure sensor has 2n cells, where n is a positive integer greater than or equal to 1.

[0047] Optionally, the 2n capacitive pressure sensor cells are arranged side by side.

[0048] Optionally, the capacitive pressure sensor includes a first capacitive pressure sensor unit and a second capacitive pressure sensor unit, which form a Wheatstone bridge. The first capacitive pressure sensor unit includes a detection capacitor and a reference capacitor, and the second capacitive pressure sensor unit includes a detection capacitor and a reference capacitor.

[0049] The upper plate of the detection capacitor of the first capacitive pressure sensor unit is electrically connected to the upper plate of the reference capacitor of the first capacitive pressure sensor unit to form a first terminal. The lower plate of the detection capacitor of the first capacitive pressure sensor unit is electrically connected to the lower plate of the reference capacitor of the second capacitive pressure sensor unit to form a second terminal. The lower plate of the reference capacitor of the first capacitive pressure sensor unit is electrically connected to the lower plate of the detection capacitor of the second capacitive pressure sensor unit to form a third terminal. The upper plate of the detection capacitor of the second capacitive pressure sensor unit is electrically connected to the upper plate of the reference capacitor of the second capacitive pressure sensor unit to form a fourth terminal.

[0050] Optionally, the distance between the upper plate and the lower plate of the reference capacitor is limited by the thickness of the second sacrificial layer.

[0051] Optionally, the distance between the upper plate and the lower plate of the detection capacitor is limited by the sum of the thicknesses of the second sacrificial layer and the third sacrificial layer.

[0052] According to another aspect of this application, a method for manufacturing a capacitive pressure sensor is provided, comprising:

[0053] A support structure, a detection capacitor, and a reference capacitor are formed on the same substrate. The support structure includes a first support structure, a second support structure, and a third support structure. The first support structure and the second support structure surround the detection capacitor, and the second support structure and the third support structure surround the reference capacitor. The upper electrode plate of the detection capacitor, the lower electrode plate of the detection capacitor, the upper electrode plate of the reference capacitor, and the lower electrode plate of the reference capacitor are physically independent of each other.

[0054] Optionally, it also includes:

[0055] An insulating layer is formed on the substrate;

[0056] A stop layer is formed on the insulating layer;

[0057] A first conductive layer is formed on the stop layer, the first conductive layer comprising a first conductive region, a second conductive region, and a third conductive region that are independent of each other;

[0058] A first sacrificial layer is formed on the first conductive layer;

[0059] A second conductive layer is formed on the first sacrificial layer, the second conductive layer including a fourth conductive region, a fifth conductive region, and a sixth conductive region that are independent of each other;

[0060] A second sacrificial layer and a third sacrificial layer are formed sequentially on the second conductive layer;

[0061] A third conductive layer is formed on the third sacrificial layer, the third conductive layer including a seventh conductive region, an eighth conductive region, and a ninth conductive region;

[0062] The first conductive region is electrically connected to the fourth conductive region and serves as the lower electrode of the detection capacitor; the seventh conductive region serves as the upper electrode of the detection capacitor.

[0063] The second conductive region is electrically connected to the fifth conductive region and serves as the lower electrode of the reference capacitor; the eighth conductive region serves as the upper electrode of the reference capacitor.

[0064] At least a portion of the second sacrificial layer and the third sacrificial layer are removed to form a first cavity between the seventh conductive region, the fourth conductive region and the first conductive region, and a second cavity between the eighth conductive region, the fifth conductive region and the second conductive region;

[0065] The third conductive region, a portion of the sixth conductive region, and the ninth conductive region are electrically connected and serve as the supporting structure.

[0066] Optionally, the third conductive layer in the first support structure and the second support structure are connected, the third conductive layer in the second support structure and the third support structure are connected, and the seventh conductive region is movable.

[0067] Optionally, the second support structure is an integral structure.

[0068] Optionally, the second support structure comprises at least two parts, and the ninth conductive region of each part is separated from each other.

[0069] Optionally, it also includes:

[0070] A plurality of first release paths are formed, the first release paths penetrate a portion of the fourth conductive region, and the first release paths are connected to the first cavity and / or the second cavity to release the sacrificial layer;

[0071] A plurality of second release paths are formed, the second release paths passing through a portion of the fifth conductive region in the reference capacitor, and the second release paths communicating with the first cavity and / or the second cavity to release the sacrificial layer.

[0072] Optionally, it also includes:

[0073] A first connection structure and a second connection structure are formed. The first conductive region and the fourth conductive region are connected through the first connection structure. The width of the first connection structure is smaller than the width of the fourth conductive region after it is penetrated. The second conductive region and the fifth conductive region are connected through the second connection structure. The width of the second connection structure is smaller than the width of the fifth conductive region after it is penetrated.

[0074] At least a portion of the first sacrificial layer is removed to form a seventh release pathway between adjacent first connection structures and an eighth release pathway between adjacent second connection structures.

[0075] Optionally, it also includes:

[0076] A third release path is formed, which extends through a portion of the third conductive region, the sixth conductive region, and the ninth conductive region in at least one support structure and communicates with the first cavity and / or the second cavity to release the sacrificial layer in the capacitive pressure sensor.

[0077] Optionally, the three release paths include a fourth release path and a fifth release path. The fourth release path is located in the first support structure, and the fifth release path is located in the third support structure. The ninth conductive region forming the fourth release path has a first release hole communicating with the fourth release path, and the ninth conductive region forming the fifth release path has a second release hole communicating with the fifth release path.

[0078] Optionally, the third release path further includes a sixth release path, the sixth release path being located in the second support structure, and the ninth conductive region forming the sixth release path having a third release hole communicating with the sixth release path.

[0079] Optionally, it also includes:

[0080] A sealing layer is formed above the third conductive layer. The sealing layer includes an opening corresponding to a seventh conductive region of the third conductive layer, and a peripheral portion surrounding the opening.

[0081] The opening in the sealing layer allows the seventh conductive region to move in the vertical direction, while the peripheral portion of the sealing layer restricts the movement of the eighth and ninth conductive regions in the vertical direction.

[0082] Optionally, it also includes:

[0083] A passivation layer is formed on top of the sealing layer.

[0084] Optionally, the seventh conductive region and the eighth conductive region are connected to the ninth conductive region in the second support structure, the seventh conductive region is also connected to the first support structure, and the eighth conductive region is also connected to the third support structure.

[0085] Optionally, it also includes:

[0086] A first conductive contact is formed, and the first conductive contact is connected to the first support structure or the third support structure.

[0087] Optionally, it also includes:

[0088] A second conductive contact is formed, and the second conductive contact is connected to the first conductive area;

[0089] A third conductive contact is formed, and the third conductive contact is connected to the first conductive region.

[0090] Optionally, the capacitive pressure sensor has 2n cells, where n is a positive integer greater than or equal to 1.

[0091] Optionally, the 2n capacitive pressure sensor cells are arranged side by side.

[0092] Optionally, the capacitive pressure sensor includes a first capacitive pressure sensor unit and a second capacitive pressure sensor unit, which form a Wheatstone bridge. The first capacitive pressure sensor unit includes a detection capacitor and a reference capacitor, and the second capacitive pressure sensor unit includes a detection capacitor and a reference capacitor.

[0093] The upper plate of the detection capacitor of the first capacitive pressure sensor unit is electrically connected to the upper plate of the reference capacitor of the first capacitive pressure sensor unit to form a first terminal. The lower plate of the detection capacitor of the first capacitive pressure sensor unit is electrically connected to the lower plate of the reference capacitor of the second capacitive pressure sensor unit to form a second terminal. The lower plate of the reference capacitor of the first capacitive pressure sensor unit is electrically connected to the lower plate of the detection capacitor of the second capacitive pressure sensor unit to form a third terminal. The upper plate of the detection capacitor of the second capacitive pressure sensor unit is electrically connected to the upper plate of the reference capacitor of the second capacitive pressure sensor unit to form a fourth terminal.

[0094] Optionally, the distance between the upper plate and the lower plate of the reference capacitor is limited by the thickness of the second sacrificial layer.

[0095] Optionally, the distance between the upper plate and the lower plate of the detection capacitor is limited by the sum of the thicknesses of the second sacrificial layer and the third sacrificial layer.

[0096] Optionally, the thickness of the second conductive layer is 1.0~3.0 μm, and the width of the first release path and / or the second release path is 0.3 μm~1.0 μm.

[0097] The capacitive pressure sensor and its manufacturing method provided in this application involve forming the detection capacitor and reference capacitor in the cell of the capacitive pressure sensor on the same substrate, simplifying the manufacturing process. Furthermore, the support structure in the cell of the capacitive pressure sensor includes a first support structure, a second support structure, and a third support structure. The first and second support structures surround the detection capacitor, and the second and third support structures surround the reference capacitor. The upper and lower electrodes of the detection capacitor, the upper electrode of the reference capacitor, and the lower electrode of the reference capacitor are physically independent of each other, preventing mutual interference and malfunction.

[0098] Furthermore, the capacitive pressure sensor also includes a grid-like second conductive layer, several first release paths penetrating a portion of the fourth conductive region in the second conductive layer, and several second release paths penetrating a portion of the fifth conductive region in the second conductive layer, communicating with the first cavity and / or the second cavity to release the sacrificial layer. This can improve the release efficiency of the sacrificial layer and reduce the difficulty of releasing the sacrificial layer, allowing for increased sensitivity of the capacitive pressure sensor by reducing the electrode spacing. Furthermore, the capacitive pressure sensor also includes a first connection structure connecting the first conductive region of the first conductive layer and the fourth conductive region of the second conductive layer, and a second connection structure connecting the second conductive region of the first conductive layer and the fifth conductive region of the second conductive layer. The width of the first connection structure is smaller than the width of the fourth conductive region after penetration, and the width of the second connection structure is smaller than the width of the fifth conductive region after penetration. A seventh release path is formed between adjacent first connection structures, and an eighth release path is formed between adjacent second connection structures, further improving the release efficiency of the sacrificial layer and reducing the difficulty of releasing the sacrificial layer.

[0099] Furthermore, the capacitive pressure sensor also includes a third release path communicating with the first cavity and / or the second cavity to release the sacrificial layer in the capacitive pressure sensor, and a ninth conductive region penetrating the third conductive layer and communicating with the corresponding third release path. Further, the release hole is located in the support structure (i.e., in the edge region of the capacitive pressure sensor), and a sealing layer seals the release hole. This reduces the impact of the sealing layer on the closed cavity within the sensing capacitor and the reference capacitor, further improving the reliability of the capacitive pressure sensor.

[0100] Furthermore, the capacitive pressure sensor provided in this application includes a reference capacitor and a detection capacitor. The detection capacitor and the reference capacitor form a half-bridge or full-bridge differential structure, which can improve the sensitivity of the capacitive pressure sensor. Furthermore, the first and second capacitive pressure sensor units forming the Wheatstone bridge have similar structures and can be obtained simultaneously during manufacturing without the need to introduce additional material layers, thus saving manufacturing costs. Attached Figure Description

[0101] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only involve some embodiments of this disclosure, and are not intended to limit this disclosure.

[0102] Figure 1 A planar schematic diagram of a capacitive pressure sensor according to an embodiment of this application is shown.

[0103] Figure 2 A schematic diagram of an equivalent circuit of a capacitive pressure sensor according to an embodiment of this application is shown.

[0104] Figure 3a The capacitive pressure sensor shown in this application embodiment is along Figure 1 A schematic diagram of a cross-section obtained by cutting line A1.

[0105] Figure 3b The capacitive pressure sensor shown in this application embodiment is along Figure 1 A schematic diagram of another cross-section obtained by cutting line A1.

[0106] Figure 3c The capacitive pressure sensor shown in this application embodiment is along Figure 1 A schematic diagram of a cross-section obtained by cutting line A2.

[0107] Figure 4 A planar schematic diagram of the second conductive layer in a capacitive pressure sensor according to an embodiment of this application is shown.

[0108] Figure 5 Another planar schematic diagram of the second conductive layer in a capacitive pressure sensor according to an embodiment of this application is shown.

[0109] Figures 6a to 6i Cross-sectional views of various stages of a method for manufacturing a capacitive pressure sensor according to an embodiment of this application are shown. Detailed Implementation

[0110] The present application will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale. Furthermore, some well-known parts may not be shown. For simplicity, a semiconductor device obtained after several steps can be depicted in a single figure.

[0111] Many specific details of this application, such as the structure, materials, dimensions, processing techniques, and methods of the devices, are described below to provide a clearer understanding of the application. However, as those skilled in the art will understand, this application may be implemented without adhering to these specific details.

[0112] Current sacrificial layer release technology involves setting a sacrificial layer release opening on the surface of a pressure-sensitive movable electrode. However, during the subsequent sealing process, problems often arise, such as the sealing material affecting the stress of the pressure-sensitive diaphragm and the sealing material entering the closed reference cavity.

[0113] This application may be presented in various forms, some of which will be described below.

[0114] Figure 1 A planar schematic diagram of a capacitive pressure sensor according to an embodiment of this application is shown. Figure 2 A schematic diagram of an equivalent circuit of a capacitive pressure sensor according to an embodiment of this application is shown. Figure 3aThe capacitive pressure sensor shown in this application embodiment is along Figure 1 A schematic diagram of a cross-section obtained by cutting line A1. Figure 3b The capacitive pressure sensor shown in this application embodiment is along Figure 1 A schematic diagram of another cross-section obtained by cutting line A1. Figure 3c The capacitive pressure sensor shown in this application embodiment is along Figure 1 A schematic diagram of a cross-section obtained by cutting line A2.

[0115] The capacitive pressure sensor provided in this application includes a plurality of capacitive pressure sensor cells. Further, there are 2n capacitive pressure sensor cells, where n is a positive integer greater than or equal to 1. For example, the 2n capacitive pressure sensor cells are arranged side-by-side.

[0116] like Figure 1 As shown, taking n=1 as an example, the capacitive pressure sensor includes a first capacitive pressure sensor unit 10 and a second capacitive pressure sensor unit 20. Exemplarily, the first capacitive pressure sensor unit 10 and the second capacitive pressure sensor unit 20 each include a capacitive pressure sensor cell. The first capacitive pressure sensor unit 10 includes a detection capacitor Cm-1 and a reference capacitor Cref-1, and the second capacitive pressure sensor unit 20 includes a detection capacitor Cm-2 and a reference capacitor Cref-2.

[0117] like Figure 1 , Figure 2 As shown, the first capacitive pressure sensor unit 10 and the second capacitive pressure sensor unit 20 in the capacitive pressure sensor form a Wheatstone bridge to obtain a differential capacitive pressure sensor, which can improve the sensitivity of the capacitive pressure sensor.

[0118] The upper plate of the detection capacitor Cm-1 of the first capacitive pressure sensor unit 10 is electrically connected to the upper plate of the reference capacitor Cref-1 of the first capacitive pressure sensor unit 10 to form a first terminal D. The lower plate of the detection capacitor Cm-1 of the first capacitive pressure sensor unit 10 is electrically connected to the lower plate of the reference capacitor Cref-2 of the second capacitive pressure sensor unit 20 to form a second terminal E. The lower plate of the reference capacitor Cref-1 of the first capacitive pressure sensor unit 10 is electrically connected to the lower plate of the detection capacitor Cm-2 of the second capacitive pressure sensor unit 20 to form a third terminal C. The upper plate of the detection capacitor Cm-2 of the second capacitive pressure sensor unit 20 is electrically connected to the upper plate of the reference capacitor Cref-2 of the second capacitive pressure sensor unit 20 to form a fourth terminal F.

[0119] It should be noted that the method proposed in this application, where the upper plates of the detection capacitor and the reference capacitor in the same capacitive pressure sensor cell are connected, and the lower plates of the detection capacitors in adjacent capacitive pressure sensor cells are connected to the lower plates of the reference capacitors in another capacitive pressure sensor cell, is only one embodiment of this application. In this application, the lower plates of the detection capacitor and the reference capacitor in the same capacitive pressure sensor cell can also be connected, and the upper plates of the detection capacitors in adjacent capacitive pressure sensor cells can be connected to the upper plates of the reference capacitors in another capacitive pressure sensor cell (for example, the same capacitive pressure sensor cell may include a reference capacitor Cref-1 and a detection capacitor Cm-2, or may include a reference capacitor Cref-2 and a detection capacitor Cm-1; correspondingly, 2n capacitive pressure sensor cells are arranged in parallel).

[0120] Figure 3a This is a schematic cross-sectional view of a cell in a capacitive pressure sensor. Figure 3b This is another schematic cross-sectional view of a cell in a capacitive pressure sensor. Figure 3c This is a cross-sectional schematic diagram showing the connection between the reference capacitor of one capacitive pressure sensor cell and the detection capacitor of another capacitive pressure sensor cell.

[0121] like Figure 3a As shown, the capacitive pressure sensor cell 10 (or capacitive pressure sensor cell 20) includes a support structure, a detection capacitor, and a reference capacitor located on the same substrate 100. The support structure includes a first support structure 113a, a second support structure 113b, and a third support structure 113c. The first support structure 113a and the second support structure 113b surround the detection capacitor, and the second support structure 113b and the third support structure 113c surround the reference capacitor. The upper electrode of the detection capacitor, the lower electrode of the detection capacitor, the upper electrode of the reference capacitor, and the lower electrode of the reference capacitor are physically independent of each other.

[0122] Furthermore, the capacitive pressure sensor cell also includes: a substrate 100; an insulating layer 201 located on the substrate 100; a stop layer 301 located on the insulating layer 201; a first conductive layer 401 including mutually independent first conductive regions 401a, second conductive regions 401b, and third conductive regions 401c; a second conductive layer 601 including mutually independent fourth conductive regions 601a, fifth conductive regions 601b, and sixth conductive regions 601c; and a third conductive layer 901 including seventh conductive regions 901a, eighth conductive regions 901b, and ninth conductive regions 901c.

[0123] The first conductive region 401a is electrically connected to the fourth conductive region 601a and serves as the lower electrode of the detection capacitor. The seventh conductive region 901a serves as the upper electrode of the detection capacitor. A first cavity 121 exists between the seventh conductive region 901a, the fourth conductive region, and the first conductive region 401a. The second conductive region 401b is electrically connected to the fifth conductive region 601b and serves as the lower electrode of the reference capacitor. The eighth conductive region 901b serves as the upper electrode of the reference capacitor. A second cavity 122 exists between the eighth conductive region 901b, the fifth conductive region 601b, and the second conductive region 401b. The third conductive region 401c, a portion of the sixth conductive region 601c, and the ninth conductive region 901c are electrically connected and serve as a supporting structure.

[0124] Furthermore, the third conductive layers in the first support structure 113a and the second support structure 113b are connected, the third conductive layers in the second support structure 113b and the third support structure 113c are connected, and the seventh conductive region 901a is movable.

[0125] Furthermore, the second support structure 113b is an integral structure. Exemplarily, the second support structure 113b comprises at least two parts, with the ninth conductive region 901c of each part being separated from each other. Further, the separated ninth conductive regions 901c in the second support structure 113b are connected via a third conductive layer 401c below their respective connected sixth conductive regions 601c. The seventh conductive region 901a and the eighth conductive region 901b are connected via the indirectly connected ninth conductive regions 901c in the second support structure 113b, thereby achieving connection between the upper electrode of the detection capacitor and the upper electrode of the reference capacitor in the same capacitive pressure sensor cell.

[0126] Furthermore, the capacitive pressure sensor cell also includes a plurality of first release paths 141 and a plurality of second release paths 142. The first release path 141 extends through a portion of the fourth conductive region 601a and communicates with the first cavity 121 and / or the second cavity 122 to release the sacrificial layer. The second release path 142 extends through a portion of the fifth conductive region 601b in the reference capacitor and communicates with the first cavity 121 and / or the second cavity 122 to release the sacrificial layer.

[0127] Furthermore, the capacitive pressure sensor cell also includes a first connecting structure 111, a second connecting structure 112, a seventh release path 147, and an eighth release path 148. The first conductive region 401a and the fourth conductive region 601a are connected by the first connecting structure 111. The width of the first connecting structure is smaller than the width of the fourth conductive region 601a after it is connected. A seventh release path 147 is formed between adjacent first connecting structures 111. The second conductive region 401b and the fifth conductive region 601b are connected by the second connecting structure 112. The width of the second connecting structure 112 is smaller than the width of the fifth conductive region 601b after it is connected. An eighth release path 148 is formed between adjacent second connecting structures 112.

[0128] Furthermore, the capacitive pressure sensor cell also includes a third release path 143, which extends through a portion of the third conductive region 401c, the sixth conductive region 601c, and the ninth conductive region 901c in at least one support structure, and communicates with the first cavity 121 and / or the second cavity 122 to release the sacrificial layer in the capacitive pressure sensor.

[0129] Furthermore, the three release paths 143 include a fourth release path 144, a fifth release path 145, and a sixth release path 146. The fourth release path 144 is located in the first support structure 113a, the fifth release path 145 is located in the third support structure 113c, and the sixth release path is located in the second support structure 113b. The ninth conductive region 901c forming the fourth release path 144 has a first release hole 151 communicating with the fourth release path 144, the ninth conductive region 901c forming the fifth release path 145 has a second release hole 152 communicating with the fifth release path 145, and the ninth conductive region 901c forming the sixth release path 146 has a third release hole 153 communicating with the sixth release path 146.

[0130] Furthermore, the capacitive pressure sensor cell also includes a sealing layer 1001 located above the third conductive layer 901. The sealing layer 1001 includes an opening 1002 corresponding to the seventh conductive region 901a of the third conductive layer 901, and a peripheral portion surrounding the opening 1002. The opening 1002 of the sealing layer 1001 allows the seventh conductive region 901a to move in the vertical direction, while the peripheral portion of the sealing layer 1001 restricts the vertical movement of the eighth conductive region 901b and the ninth conductive region 901c.

[0131] Furthermore, the capacitive pressure sensor cell also includes a passivation layer 1201 located above the sealing layer 1001.

[0132] Furthermore, the capacitive pressure sensor cell also includes a first sacrificial layer 501 located between the first conductive layer 401 and the second conductive layer 601, at least a portion of the first sacrificial layer 501 being removed to form a fourth release path 144, a fifth release path 145, a seventh release path 147 and an eighth release path 148 between the first conductive layer 401 and the second conductive layer 601.

[0133] Furthermore, the capacitive pressure sensor cell also includes a second sacrificial layer 701 and a third sacrificial layer 801 located between the second conductive layer 601 and the third conductive layer 901, and at least a portion of the second sacrificial layer 701 and the third sacrificial layer 801 are removed to form a first cavity 121 and a second cavity 122.

[0134] Furthermore, the seventh conductive region 901a and the eighth conductive region 901b are connected to the ninth conductive region 901c in the second support structure 113b. The seventh conductive region 901a is also connected to the first support structure 113a, and the eighth conductive region 901b is also connected to the third support structure 113c.

[0135] Furthermore, the capacitive pressure sensor cell also includes a first conductive contact D, a second conductive contact C, and a third conductive contact E. The first conductive contact D is connected to the first support structure 113a or the third support structure 113b. The second conductive contact C is connected to the first conductive region 401a. The third conductive contact E is connected to the second conductive region 401b. Specifically, the second conductive contact C is directly connected to the first conductive region 401a of the capacitive pressure sensor cell itself, or indirectly connected to its own first conductive region 401a via the first conductive region 401a of other capacitive pressure sensor cells, and / or the third conductive contact E is directly connected to the second conductive region 401b of the capacitive pressure sensor cell itself, or indirectly connected to its own first conductive region 401a via the second conductive region 401b of other capacitive pressure sensor cells.

[0136] Furthermore, the distance between the upper and lower plates of the reference capacitor is limited by the thickness of the second sacrificial layer 701. The distance between the upper and lower plates of the detection capacitor is limited by the sum of the thicknesses of the second sacrificial layer 701 and the third sacrificial layer 801. Therefore, during manufacturing, the capacitance values ​​of the detection capacitor and the reference capacitor can be adjusted by changing the thicknesses of the second sacrificial layer 701 and the third sacrificial layer 801, so that the capacitance value of the reference capacitor matches the capacitance value of the detection capacitor.

[0137] Figure 3b The cell of the capacitive pressure sensor shown is... Figure 3a The difference between the capacitive pressure sensor cells in the middle lies in the third release path and the second support structure.

[0138] like Figure 3b As shown, the second support structure 113b is an integral structure. For example, the seventh conductive region 901a and the eighth conductive region 901b are connected through the ninth conductive region 901c in the second support structure 113b, so as to realize the connection between the upper plate of the detection capacitor and the upper plate of the reference capacitor in the same capacitive pressure sensor cell.

[0139] Furthermore, the three release paths 143 include a fourth release path 144 and a fifth release path 145. The fourth release path 144 is located in the first support structure 113a, and the fifth release path 145 is located in the third support structure 113c. The ninth conductive region 901c forming the fourth release path 144 has a first release hole 151 communicating with the fourth release path 144, and the ninth conductive region 901c forming the fifth release path 145 has a second release hole 152 communicating with the fifth release path 145.

[0140] like Figure 3c As shown, the lower plate of the reference capacitor Cref-1 of the capacitive pressure sensor cell 10 is connected to the lower plate of the detection capacitor Cm-2 of the capacitive pressure sensor cell 20 to form the third terminal C. Further, the second conductive region 401b in the capacitive pressure sensor cell 10 and the first conductive region 401a in the capacitive pressure sensor cell 20 are connected via the third conductive region 401c in the second support structure 113b of the capacitive pressure sensor cell 10 and 20, respectively, and conductive contacts are led out through the third support structure 113c connected to the second conductive region 401b in the capacitive pressure sensor cell 10 to form the third terminal C. The seventh conductive region 901a in the capacitive pressure sensor cell 20 leads out conductive contacts through the first support structure 113a to form the fourth terminal F. The eighth conductive region 901b in the capacitive pressure sensor cell 10 leads out conductive contacts (not shown) through a corresponding support structure to form the first terminal D.

[0141] Figure 4 A planar schematic diagram of the second conductive layer in a capacitive pressure sensor according to an embodiment of this application is shown. Figure 5 Another planar schematic diagram of the second conductive layer in a capacitive pressure sensor according to an embodiment of this application is shown. Figures 6a to 6i Cross-sectional views of various stages of a method for manufacturing a capacitive pressure sensor according to an embodiment of this application are shown.

[0142] Figures 6a to 6i It shows Figure 3a The cross-sectional views of the capacitive pressure sensor cell at different stages shown can be understood. Figure 3b The manufacturing methods for the capacitive pressure sensor cells shown and the structures connecting adjacent cells are all applicable to the manufacturing methods described above.

[0143] like Figure 6a As shown, an isolation layer and a first conductive layer 401 are formed on the substrate 100.

[0144] Further, the substrate 100 includes opposing first and second surfaces. An isolation layer and a first conductive layer 401 are sequentially formed on the first surface of the substrate 100, the isolation layer electrically isolating the first conductive layer 401 from the substrate 100. Exemplarily, the isolation layer includes an insulating layer 201 located on the first surface of the substrate 100 and a stop layer 301 located on the surface of the insulating layer. The first conductive layer 401 is located on the surface of the stop layer 301. The first conductive layer 401 includes mutually independent first conductive regions 401a, second conductive regions 401b, and third conductive regions 401c.

[0145] For example, in the crystal orientation is <100> An insulating layer 201 is formed on a substrate 100, for example, by thermal oxidation, low-pressure chemical vapor deposition (LPCVD), or plasma-enhanced chemical vapor deposition (PECVD). The substrate 100 is, for example, a silicon substrate. The insulating layer 201 is, for example, a silicon dioxide layer, to electrically isolate the subsequently formed first conductive layer 401 from the substrate 100. The thickness of the insulating layer 201 is 0.5 μm to 3 μm. Next, a stop layer 301 is formed on the surface of the insulating layer 201, for example, by low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition (PECVD). The stop layer 301 is, for example, a silicon nitride layer, a silicon-rich silicon nitride layer, or an aluminum oxide layer, to serve as a stop layer for the release of the sacrificial layer in a subsequent capacitive pressure sensor. Next, a conductive material layer is deposited on the surface of the stop layer 301, and the conductive material layer is photolithographically and etched to form a first conductive layer 401 including a first conductive region 401a, a second conductive region 401b, and a third conductive region 401c that are independent of each other. The first conductive layer 401 is, for example, a doped polysilicon layer.

[0146] like Figure 6b As shown, a patterned first sacrificial layer 501 is formed on the surfaces of the first conductive layer 401 and the exposed stop layer 301.

[0147] Furthermore, the first sacrificial layer 501 also includes a first through-hole 502 that penetrates the first sacrificial layer 501 to reach the surface of the first conductive layer 401.

[0148] For example, a silicon dioxide layer is deposited on the surface of the first conductive layer 401 by means of low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition (PECVD), and the silicon dioxide layer is photolithographically etched to form a first sacrificial layer 501. The first sacrificial layer 501 includes a first via 502 reaching the surface of the first conductive layer 401.

[0149] like Figure 6cAs shown, a second conductive layer 601 is formed, comprising a fourth conductive region 601a, a fifth conductive region 601b, and a sixth conductive region 601c that are independent of each other.

[0150] Further, while forming the second conductive layer 601 above the first sacrificial layer 501, a first connection structure 111 and a second connection structure 112 are formed in a portion of the second through-holes, and a third connection structure is formed in the remaining second through-holes to connect the third conductive region 401c of the first conductive layer 401 in the support structure to the sixth conductive region 601c of the second conductive layer 601. Further, the second conductive layer 601 also includes a second through-hole 502 penetrating the second conductive layer 601 to reach the surface of the first sacrificial layer 501. In this embodiment, see... Figure 4 The fourth conductive region 601a of the second conductive layer 601 includes multiple rows of block-shaped conductive layers, each row including, for example, five block-shaped conductive layers. In an alternative embodiment, see... Figure 5 The second conductive layer 601 shown includes a fourth conductive region 601a comprising multiple rows of blocky conductive layers, each row including, for example, one blocky conductive layer, thereby increasing the effective area of ​​the lower electrode of the detection capacitor. Further, the width of the second via 602 is 0.3 μm to 1.0 μm. The thickness of the second conductive layer 601 is 1.0 to 3.0 μm. Further, the width of the second via 602 is matched with the thickness of the second via 602 to give the second via 602 a relatively high aspect ratio. For example, the aspect ratio of the second via 602 is approximately 3.

[0151] For example, a conductive material layer is deposited on the surface of the first sacrificial layer 501 and in the first via 502, and a plurality of second vias 602 are formed by photolithography and etching of the conductive material layer, penetrating the conductive material layer and reaching the surface of the first sacrificial layer 501. The second vias 602 mesh the conductive material layer on the surface of the first sacrificial layer 501 and in the first via 502 to form a second conductive layer 601 including mutually independent fourth conductive regions 601a, fifth conductive regions 601b, and sixth conductive regions 601c. The second conductive layer 601 is, for example, a doped polysilicon layer. The thickness of the second conductive layer 601 is 1.0~3.0 μm. The width of the second via 602 is 0.3 μm~1.0 μm. The thickness of the second conductive layer 601 is 1.0~3.0 μm. Further, the width of the second via 602 is matched with the thickness of the second via 602 so that the second via 602 has a relatively high aspect ratio. For example, the aspect ratio of the second through hole 602 is approximately 3.

[0152] Furthermore, the first conductive region 401a and the fourth conductive region 601a are connected by a first connecting structure 111 and serve as the lower electrode of the detection capacitor. The width of the first connecting structure 111 is smaller than the width of the fourth conductive region 601a after it is connected. The second conductive region 401b and the fifth conductive region 601b are connected by a second connecting structure 112 and serve as the lower electrode of the reference capacitor. The width of the second connecting structure 112 is smaller than the width of the fifth conductive region 601b after it is connected.

[0153] Next, a second sacrificial layer 701 and a third sacrificial layer 801 are formed sequentially on the second conductive layer 601.

[0154] like Figure 6d As shown, a patterned second sacrificial layer 701 is formed on the second conductive layer 601.

[0155] Furthermore, while forming the second sacrificial layer 701 on the surface of the second conductive layer 601 and the first sacrificial layer 501 exposed via the second via 602, a plurality of first release pathways 141 and a plurality of second release pathways 142 for subsequent release of the sacrificial layer are formed in the second conductive layer 601. The second sacrificial layer 701 also includes a third via 702 reaching the surface of the fifth conductive region 601b of the second conductive layer 601.

[0156] Exemplarily, a silicon dioxide layer is deposited over the second conductive layer 601, for example, by low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition (PECVD). Because the second via 602 has a high aspect ratio, the silicon dioxide layer does not completely fill the second via 602, thereby forming a plurality of first release paths 141 and a plurality of second release paths 142 in the second conductive layer 601 for subsequent release of the sacrificial layer. The deposited silicon dioxide layer is then photolithographically and etched to form a second sacrificial layer 701, which also includes a third via 702 reaching the surface of the fifth conductive region 601b of the second conductive layer 601. The third via 702 is subsequently used to define the spacing between the upper and lower electrodes of a reference capacitor.

[0157] like Figure 6e As shown, a cavity is formed in the third release path 143 that penetrates the sixth conductive region 601c of the second conductive layer 601 (including the cavity 144a in the subsequently formed fourth release path 144, the cavity 145a in the subsequently formed fifth release path 145, and the cavity 146a in the subsequently formed sixth release path 146).

[0158] Furthermore, cavities 144a, 145a, and 146a are connected to the first release passage 141 and / or the second release passage 142.

[0159] For example, the second sacrificial layer 701 is etched by photolithography, and the remaining conductive material layer at the bottom is further etched isotropically to form cavities 144a, 145a, and 146a in the sixth conductive region 601c of the second conductive layer 601. Cavities 144a, 145a, and 146a serve as exchange channels for corrosion gas / liquid and reaction products during the subsequent release of the sacrificial layer.

[0160] In other embodiments, such as Figure 6f As shown, only Figure 6e The structure of the middle part. In, for example... Figure 6e The structure shown also includes a release opening 149 located in the first sacrificial layer 501 and connected to the first release passage 141, the second release passage 142, the cavity 144a, the cavity 145a, and the cavity 146a, to further improve the release efficiency of the sacrificial layer. It can be used to manufacture small-pitch capacitive pressure sensors.

[0161] like Figure 6g As shown, a patterned third sacrificial layer 801 is formed on the surface of the second sacrificial layer 701 and the second conductive layer 601 exposed via the third via 702.

[0162] For example, a silicon dioxide layer is formed over the second sacrificial layer 701 using low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition (PECVD). A third sacrificial layer 801 and a fourth via 802, located in the support region and penetrating through the second sacrificial layer 701 and the third sacrificial layer 801 to reach the surface of the sixth conductive region 601c of the second conductive layer 601, are then formed. The fourth via 802 is used for subsequent formation of the support structure. The third sacrificial layer located on the surface of the fifth conductive region 601b is, for example, a conformal layer.

[0163] like Figure 6h As shown, a third conductive layer 901 is formed on the surface of the third sacrificial layer 801 and the second conductive layer 601 exposed via the fourth via 802.

[0164] Furthermore, the third conductive layer 901 includes a seventh conductive region 901a, an eighth conductive region 901b, and a ninth conductive region 901c. The third conductive layer 901 also includes a first release hole 151, a second release hole 152, and a third release hole 153 located in the ninth conductive region 901c.

[0165] Exemplarily, a conductive material layer is deposited on the surface of the third sacrificial layer 801 and the second conductive layer 601 exposed via the fourth via 802, for example by low-pressure chemical vapor deposition (LPCVD) or epitaxy. This conductive material layer is then photolithographically and etched to form a seventh conductive region 901a, an eighth conductive region 901b, and a ninth conductive region 901c, and a first release via 151, a second release via 152, and a third release via 153 are formed in the ninth conductive region 901c. The third conductive layer 901 is, for example, a doped polysilicon layer. The thickness of the third conductive layer 901 is 1.0 μm to 3.0 μm. A portion of the ninth conductive region 901c of the third conductive layer 901 fills the fourth via 802 to form a support structure.

[0166] Furthermore, the seventh conductive region 901a serves as the upper electrode of the detection capacitor, and the eighth conductive region 901b serves as the upper electrode of the reference capacitor.

[0167] like Figure 6i As shown, at least a portion of the first sacrificial layer 501, the second sacrificial layer 701, and the third sacrificial layer 801 are removed.

[0168] For example, selective wet etching of HF acid or BOE solution / gas is used to remove portions of the third sacrificial layer 801, the second sacrificial layer 701, and the first sacrificial layer 501 through the first release hole 151, the second release hole 152, the third release hole 153, the first release path 141, the second release path 142, the cavity 144a, the cavity 145a, and the cavity 146a to form the third release path 143 (e.g., including the fourth release path 144, the fifth release path 145, and the sixth release path 146), the seventh release path 147, and the eighth release path 148. Then, the first sacrificial layer 501, the second sacrificial layer 701, and the third sacrificial layer 801 are released through the above-mentioned release paths, and the first cavity 121 is formed between the seventh conductive region 901a, the fourth conductive region 601a, and the first conductive region 401a, and the second cavity 122 is formed between the eighth conductive region 901b, the fifth conductive region 601b, and the second conductive region 401b. The third conductive region 401c, a portion of the sixth conductive region 601c, and the ninth conductive region 901c are electrically connected and serve as a support structure. The support structure includes a first support structure 113a, a second support structure 113b, and a third support structure 113c. The first support structure 113a and the second support structure 113b surround the detection capacitor, and the second support structure 113b and the third support structure 113c surround the reference capacitor.

[0169] Based on the above manufacturing process, the electrode spacing between the upper and lower plates in the reference capacitor is determined by the thickness of the third sacrificial layer, while the electrode spacing between the upper and lower plates in the detection capacitor is determined by the total thickness of the second and third sacrificial layers. In other words, the thicknesses of the second and third sacrificial layers are controlled to ensure that the reference capacitor and the detection capacitor are matched.

[0170] Then as Figure 3a As shown, a sealing layer 1001 is formed on the surface of a portion of the third conductive layer 901 to seal the first release hole 151, the second release hole 152, and the third release hole 153.

[0171] Furthermore, the sealing layer 1001 includes an opening 1002 corresponding to the seventh conductive region 901a of the third conductive layer, and a peripheral portion surrounding the opening 1002. The opening 1002 of the sealing layer 1001 allows the seventh conductive region 901a to move vertically, while the peripheral portion of the sealing layer 1001 restricts the vertical movement of the eighth conductive region 901b and the ninth conductive region 901c.

[0172] Furthermore, a passivation layer 1201 is formed above the sealing layer 1001.

[0173] For example, a sealing layer 1001 is deposited using low-pressure chemical vapor deposition (LPCVD), plasma-enhanced chemical vapor deposition (PECVD), or high-density plasma (HDP) chemical vapor deposition to seal the first release hole 151, the second release hole 152, and the third release hole 153, thereby forming a closed cavity with a specific pressure in the capacitive pressure sensor. The pressure p0 within the closed cavity is typically much less than 1 Bar, and further, the pressure within the closed cavity is, for example, 100 mTorr to 5 Torr. Specifically, the sealing layer 1001 can be a silicon dioxide layer, a silicon nitride layer, or a borosilicate glass (BPSG) layer, etc. The thickness of the sealing layer 1001 is 1.0 μm to 4.0 μm.

[0174] Next, the sealing layer 1001 is photolithographically etched to form lead holes. Then, a metal layer is deposited by sputtering or evaporation and photolithographically etched to form conductive contacts. The conductive contacts can be Au or Al, or alloys such as Cr+Au or Ti+Pt+Au, or pure aluminum (Al), aluminum-silicon (Al-Si1%), or Ti+TiN+Al-Si. The thickness of the conductive contacts is generally 0.5μm to 2μm.

[0175] Next, a passivation layer 1201 is formed using plasma-enhanced chemical vapor deposition (PECVD) and patterning. The passivation layer 1201 can be silicon nitride, silicon-rich silicon nitride, or aluminum oxide, etc. The passivation layer 1201 is located on the sealing layer 1001 and exposes the conductive contacts.

[0176] The capacitive pressure sensor and its manufacturing method provided in this application involve forming the detection capacitor and reference capacitor in the cell of the capacitive pressure sensor on the same substrate, simplifying the manufacturing process. Furthermore, the support structure in the cell of the capacitive pressure sensor includes a first support structure, a second support structure, and a third support structure. The first and second support structures surround the detection capacitor, and the second and third support structures surround the reference capacitor. The upper and lower electrodes of the detection capacitor, the upper electrode of the reference capacitor, and the lower electrode of the reference capacitor are physically independent of each other, preventing mutual interference and malfunction.

[0177] Furthermore, the capacitive pressure sensor also includes a grid-like second conductive layer, several first release paths penetrating a portion of the fourth conductive region in the second conductive layer, and several second release paths penetrating a portion of the fifth conductive region in the second conductive layer, communicating with the first cavity and / or the second cavity to release the sacrificial layer. This can improve the release efficiency of the sacrificial layer and reduce the difficulty of releasing the sacrificial layer, allowing for increased sensitivity of the capacitive pressure sensor by reducing the electrode spacing. Furthermore, the capacitive pressure sensor also includes a first connection structure connecting the first conductive region of the first conductive layer and the fourth conductive region of the second conductive layer, and a second connection structure connecting the second conductive region of the first conductive layer and the fifth conductive region of the second conductive layer. The width of the first connection structure is smaller than the width of the fourth conductive region after penetration, and the width of the second connection structure is smaller than the width of the fifth conductive region after penetration. A seventh release path is formed between adjacent first connection structures, and an eighth release path is formed between adjacent second connection structures, further improving the release efficiency of the sacrificial layer and reducing the difficulty of releasing the sacrificial layer.

[0178] Furthermore, the capacitive pressure sensor also includes a third release path communicating with the first cavity and / or the second cavity to release the sacrificial layer in the capacitive pressure sensor, and a ninth conductive region penetrating the third conductive layer and communicating with the corresponding third release path. Further, the release hole is located in the support structure (i.e., in the edge region of the capacitive pressure sensor), and a sealing layer seals the release hole. This reduces the impact of the sealing layer on the closed cavity within the sensing capacitor and the reference capacitor, further improving the reliability of the capacitive pressure sensor.

[0179] Furthermore, the capacitive pressure sensor provided in this application includes a reference capacitor and a detection capacitor. The detection capacitor and the reference capacitor form a half-bridge or full-bridge differential structure, which can improve the sensitivity of the capacitive pressure sensor. Furthermore, the first and second capacitive pressure sensor units forming the Wheatstone bridge have similar structures and can be obtained simultaneously during manufacturing without the need to introduce additional material layers, thus saving manufacturing costs.

[0180] The above description does not provide detailed explanations of the technical aspects of each layer's patterning, etching, etc. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0181] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. The scope of this application is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this application, and all such substitutions and modifications should fall within the scope of this application.

Claims

1. A capacitive pressure sensor, characterized in that, It includes a plurality of capacitive pressure sensor cells, wherein the capacitive pressure sensor cells include: The support structure, the detection capacitor, and the reference capacitor are located on the same substrate. The support structure includes a first support structure, a second support structure, and a third support structure. The first support structure and the second support structure surround the detection capacitor, and the second support structure and the third support structure surround the reference capacitor. The upper plate of the detection capacitor, the lower plate of the detection capacitor, the upper plate of the reference capacitor, and the lower plate of the reference capacitor are physically independent of each other. A first conductive layer, comprising a first conductive region and a second conductive region that are independent of each other; The second conductive layer includes a fourth conductive region and a fifth conductive region that are independent of each other. The third conductive layer includes a seventh conductive region and an eighth conductive region; The first conductive region is electrically connected to the fourth conductive region and serves as the lower electrode of the detection capacitor; the seventh conductive region serves as the upper electrode of the detection capacitor, and a first cavity is formed between the seventh conductive region, the fourth conductive region, and the first conductive region. The second conductive region is electrically connected to the fifth conductive region and serves as the lower electrode of the reference capacitor; the eighth conductive region serves as the upper electrode of the reference capacitor, and a second cavity is formed between the eighth conductive region, the fifth conductive region, and the second conductive region.

2. The capacitive pressure sensor according to claim 1, characterized in that, Also includes: Substrate; An insulating layer located on the substrate; A stop layer, the stop layer being located on the insulating layer; A first conductive layer, the first conductive layer further includes a third conductive region that is independent of the first conductive region and the second conductive region; The second conductive layer further includes a sixth conductive region that is independent of the fourth conductive region and the fifth conductive region; The third conductive layer further includes a ninth conductive region; The third conductive region, a portion of the sixth conductive region, and the ninth conductive region are electrically connected and serve as the supporting structure.

3. The capacitive pressure sensor according to claim 1, characterized in that, The third conductive layer in the first support structure and the second support structure is connected, and the third conductive layer in the second support structure and the third support structure is connected, and the seventh conductive region is movable.

4. The capacitive pressure sensor according to claim 3, characterized in that, The second support structure is an integral structure.

5. The capacitive pressure sensor according to claim 4, characterized in that, The second support structure comprises at least two parts, and the ninth conductive region of each part is separated from each other.

6. The capacitive pressure sensor according to claim 2, characterized in that, Also includes: A plurality of first release paths, the first release paths extending through a portion of the fourth conductive region, the first release paths communicating with the first cavity and / or the second cavity to release the sacrificial layer; Several second release paths, each second release path penetrating a portion of the fifth conductive region in the reference capacitor, the second release path communicating with the first cavity and / or the second cavity to release the sacrificial layer.

7. The capacitive pressure sensor according to claim 6, characterized in that, Also includes: The first conductive region and the fourth conductive region are connected by a first connecting structure. The width of the first connecting structure is smaller than the width of the fourth conductive region after it is connected. A seventh release path is formed between adjacent first connecting structures. The second conductive region and the fifth conductive region are connected by a second connecting structure. The width of the second connecting structure is smaller than the width of the fifth conductive region after it is connected. An eighth release path is formed between adjacent second connecting structures.

8. The capacitive pressure sensor according to claim 6 or 7, characterized in that, Also includes: A third release path extends through a portion of the third conductive region, the sixth conductive region, and the ninth conductive region in at least one support structure, and communicates with the first cavity and / or the second cavity to release the sacrificial layer in the capacitive pressure sensor.

9. The capacitive pressure sensor according to claim 8, characterized in that, The three release paths include a fourth release path and a fifth release path. The fourth release path is located in the first support structure, and the fifth release path is located in the third support structure. The ninth conductive region forming the fourth release path has a first release hole communicating with the fourth release path, and the ninth conductive region forming the fifth release path has a second release hole communicating with the fifth release path.

10. The capacitive pressure sensor according to claim 8, characterized in that, The third release path also includes a sixth release path, which is located in the second support structure. The ninth conductive region forming the sixth release path has a third release hole that communicates with the sixth release path.

11. The capacitive pressure sensor according to claim 2, characterized in that, Also includes: A sealing layer located above the third conductive layer, the sealing layer including an opening corresponding to the seventh conductive region of the third conductive layer, and a peripheral portion surrounding the opening. The opening in the sealing layer allows the seventh conductive region to move in the vertical direction, while the peripheral portion of the sealing layer restricts the movement of the eighth and ninth conductive regions in the vertical direction.

12. The capacitive pressure sensor according to claim 11, characterized in that, Also includes: A passivation layer located above the sealing layer.

13. The capacitive pressure sensor according to claim 9, characterized in that, Also includes: A first sacrificial layer is located between the first conductive layer and the second conductive layer, and at least a portion of the first sacrificial layer is removed to form the fourth, fifth, seventh, and eighth release pathways between the first and second conductive layers.

14. The capacitive pressure sensor according to claim 2, characterized in that, Also includes: A second sacrificial layer and a third sacrificial layer are located between the second conductive layer and the third conductive layer, and at least a portion of the second sacrificial layer and the third sacrificial layer are removed to form the first cavity and the second cavity.

15. The capacitive pressure sensor according to claim 2, characterized in that, The seventh conductive region and the eighth conductive region are connected to the ninth conductive region in the second support structure. The seventh conductive region is also connected to the first support structure, and the eighth conductive region is also connected to the third support structure.

16. The capacitive pressure sensor according to claim 15, characterized in that, Also includes: The first conductive contact is connected to either the first support structure or the third support structure.

17. The capacitive pressure sensor according to claim 2, characterized in that, Also includes: The second conductive contact is connected to the first conductive area; The third conductive contact is connected to the second conductive area.

18. The capacitive pressure sensor according to any one of claims 1-7, characterized in that, The capacitive pressure sensor has 2n cells, where n is a positive integer greater than or equal to 1.

19. The capacitive pressure sensor according to claim 18, characterized in that, The 2n capacitive pressure sensor cells are arranged side by side.

20. The capacitive pressure sensor according to claim 18, characterized in that, The capacitive pressure sensor includes a first capacitive pressure sensor unit and a second capacitive pressure sensor unit, which form a Wheatstone bridge. The first capacitive pressure sensor unit includes a detection capacitor and a reference capacitor, and the second capacitive pressure sensor unit includes a detection capacitor and a reference capacitor. The upper plate of the detection capacitor of the first capacitive pressure sensor unit is electrically connected to the upper plate of the reference capacitor of the first capacitive pressure sensor unit to form a first terminal. The lower plate of the detection capacitor of the first capacitive pressure sensor unit is electrically connected to the lower plate of the reference capacitor of the second capacitive pressure sensor unit to form a second terminal. The lower plate of the reference capacitor of the first capacitive pressure sensor unit is electrically connected to the lower plate of the detection capacitor of the second capacitive pressure sensor unit to form a third terminal. The upper plate of the detection capacitor of the second capacitive pressure sensor unit is electrically connected to the upper plate of the reference capacitor of the second capacitive pressure sensor unit to form a fourth terminal.

21. The capacitive pressure sensor according to claim 14, characterized in that, The distance between the upper and lower plates of the reference capacitor is limited by the thickness of the second sacrificial layer.

22. The capacitive pressure sensor according to claim 14, characterized in that, The distance between the upper plate and the lower plate of the detection capacitor is limited by the sum of the thicknesses of the second sacrificial layer and the third sacrificial layer.

23. A method for manufacturing a capacitive pressure sensor, characterized in that, include: A support structure, a detection capacitor, and a reference capacitor are formed on the same substrate. The support structure includes a first support structure, a second support structure, and a third support structure. The first support structure and the second support structure surround the detection capacitor, and the second support structure and the third support structure surround the reference capacitor. The upper electrode plate of the detection capacitor, the lower electrode plate of the detection capacitor, the upper electrode plate of the reference capacitor, and the lower electrode plate of the reference capacitor are physically independent of each other. A first conductive layer is formed, the first conductive layer including a first conductive region and a second conductive region that are independent of each other; A second conductive layer is formed, the second conductive layer including a fourth conductive region and a fifth conductive region that are independent of each other; A third conductive layer is formed, the third conductive layer including a seventh conductive region and an eighth conductive region; The first conductive region is electrically connected to the fourth conductive region and serves as the lower electrode of the detection capacitor; the seventh conductive region serves as the upper electrode of the detection capacitor. The second conductive region is electrically connected to the fifth conductive region and serves as the lower electrode of the reference capacitor; The eighth conductive region serves as the upper plate of the reference capacitor; A first cavity is formed between the seventh conductive region, the fourth conductive region and the first conductive region, and a second cavity is formed between the eighth conductive region, the fifth conductive region and the second conductive region.

24. The method for manufacturing a capacitive pressure sensor according to claim 23, characterized in that, Also includes: An insulating layer is formed on the substrate; A stop layer is formed on the insulating layer; A first conductive layer is formed on the stop layer, and the first conductive layer further includes a third conductive region that is independent of the first conductive region and the second conductive region. A first sacrificial layer is formed on the first conductive layer; A second conductive layer is formed on the first sacrificial layer, and the second conductive layer further includes a sixth conductive region that is independent of the fourth conductive region and the fifth conductive region. A second sacrificial layer and a third sacrificial layer are formed sequentially on the second conductive layer; A third conductive layer is formed on the third sacrificial layer, and the third conductive layer further includes a ninth conductive region; At least a portion of the second sacrificial layer and the third sacrificial layer are removed to form a first cavity between the seventh conductive region, the fourth conductive region and the first conductive region, and a second cavity between the eighth conductive region, the fifth conductive region and the second conductive region; The third conductive region, a portion of the sixth conductive region, and the ninth conductive region are electrically connected and serve as the supporting structure.

25. The method for manufacturing a capacitive pressure sensor according to claim 23, characterized in that, The third conductive layer in the first support structure and the second support structure is connected, and the third conductive layer in the second support structure and the third support structure is connected, and the seventh conductive region is movable.

26. The method for manufacturing a capacitive pressure sensor according to claim 25, characterized in that, The second support structure is an integral structure.

27. The method for manufacturing a capacitive pressure sensor according to claim 26, characterized in that, The second support structure comprises at least two parts, and the ninth conductive region of each part is separated from each other.

28. The method for manufacturing a capacitive pressure sensor according to claim 25, characterized in that, Also includes: A plurality of first release paths are formed, the first release paths penetrate a portion of the fourth conductive region, and the first release paths are connected to the first cavity and / or the second cavity to release the sacrificial layer; A plurality of second release paths are formed, the second release paths passing through a portion of the fifth conductive region in the reference capacitor, and the second release paths communicating with the first cavity and / or the second cavity to release the sacrificial layer.

29. The method for manufacturing a capacitive pressure sensor according to claim 28, characterized in that, Also includes: A first connection structure and a second connection structure are formed. The first conductive region and the fourth conductive region are connected through the first connection structure. The width of the first connection structure is smaller than the width of the fourth conductive region after it is penetrated. The second conductive region and the fifth conductive region are connected through the second connection structure. The width of the second connection structure is smaller than the width of the fifth conductive region after it is penetrated. At least a portion of the first sacrificial layer is removed to form a seventh release pathway between adjacent first connection structures and an eighth release pathway between adjacent second connection structures.

30. The method for manufacturing a capacitive pressure sensor according to claim 28 or 29, characterized in that, Also includes: A third release path is formed, which extends through a portion of the third conductive region, the sixth conductive region, and the ninth conductive region in at least one support structure and communicates with the first cavity and / or the second cavity to release the sacrificial layer in the capacitive pressure sensor.

31. The method for manufacturing a capacitive pressure sensor according to claim 30, characterized in that, The three release paths include a fourth release path and a fifth release path. The fourth release path is located in the first support structure, and the fifth release path is located in the third support structure. The ninth conductive region forming the fourth release path has a first release hole communicating with the fourth release path, and the ninth conductive region forming the fifth release path has a second release hole communicating with the fifth release path.

32. The method for manufacturing a capacitive pressure sensor according to claim 30, characterized in that, The third release path also includes a sixth release path, which is located in the second support structure. The ninth conductive region forming the sixth release path has a third release hole that communicates with the sixth release path.

33. The method for manufacturing a capacitive pressure sensor according to claim 24, characterized in that, Also includes: A sealing layer is formed above the third conductive layer. The sealing layer includes an opening corresponding to a seventh conductive region of the third conductive layer, and a peripheral portion surrounding the opening. The opening in the sealing layer allows the seventh conductive region to move in the vertical direction, while the peripheral portion of the sealing layer restricts the movement of the eighth and ninth conductive regions in the vertical direction.

34. The method for manufacturing a capacitive pressure sensor according to claim 33, characterized in that, Also includes: A passivation layer is formed on top of the sealing layer.

35. The method for manufacturing a capacitive pressure sensor according to claim 24, characterized in that, The seventh conductive region and the eighth conductive region are connected to the ninth conductive region in the second support structure. The seventh conductive region is also connected to the first support structure, and the eighth conductive region is also connected to the third support structure.

36. The method for manufacturing a capacitive pressure sensor according to claim 35, characterized in that, Also includes: A first conductive contact is formed, and the first conductive contact is connected to the first support structure or the third support structure.

37. The method for manufacturing a capacitive pressure sensor according to claim 24, characterized in that, Also includes: A second conductive contact is formed, and the second conductive contact is connected to the first conductive area; A third conductive contact is formed, which is connected to the second conductive area.

38. A method for manufacturing a capacitive pressure sensor according to any one of claims 23-29, characterized in that, The capacitive pressure sensor has 2n cells, where n is a positive integer greater than or equal to 1.

39. The method for manufacturing a capacitive pressure sensor according to claim 38, characterized in that, The 2n capacitive pressure sensor cells are arranged side by side.

40. The method for manufacturing a capacitive pressure sensor according to claim 38, characterized in that, The capacitive pressure sensor includes a first capacitive pressure sensor unit and a second capacitive pressure sensor unit, which form a Wheatstone bridge. The first capacitive pressure sensor unit includes a detection capacitor and a reference capacitor, and the second capacitive pressure sensor unit includes a detection capacitor and a reference capacitor. The upper plate of the detection capacitor of the first capacitive pressure sensor unit is electrically connected to the upper plate of the reference capacitor of the first capacitive pressure sensor unit to form a first terminal. The lower plate of the detection capacitor of the first capacitive pressure sensor unit is electrically connected to the lower plate of the reference capacitor of the second capacitive pressure sensor unit to form a second terminal. The lower plate of the reference capacitor of the first capacitive pressure sensor unit is electrically connected to the lower plate of the detection capacitor of the second capacitive pressure sensor unit to form a third terminal. The upper plate of the detection capacitor of the second capacitive pressure sensor unit is electrically connected to the upper plate of the reference capacitor of the second capacitive pressure sensor unit to form a fourth terminal.

41. The method for manufacturing a capacitive pressure sensor according to claim 24, characterized in that, The distance between the upper and lower plates of the reference capacitor is limited by the thickness of the second sacrificial layer.

42. The method for manufacturing a capacitive pressure sensor according to claim 24, characterized in that, The distance between the upper plate and the lower plate of the detection capacitor is limited by the sum of the thicknesses of the second sacrificial layer and the third sacrificial layer.

43. The method for manufacturing a capacitive pressure sensor according to claim 28, characterized in that, The thickness of the second conductive layer is 1.0~3.0 μm, and the width of the first release path and / or the second release path is 0.3 μm~1.0 μm.

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