Capacitive pressure sensor and manufacturing method thereof

Abstract

The invention discloses a capacitive pressure sensor and a manufacturing method thereof, the capacitive pressure sensor comprises a plurality of capacitive pressure sensor cells, and each capacitive pressure sensor cell comprises a supporting structure, a detection capacitor and a reference capacitor which are located on the same substrate. The supporting structure comprises a first supporting structure, a second supporting structure and a third supporting structure, the first supporting structure and the second supporting structure surround the detection capacitor, and the second supporting structure and the third supporting structure surround the reference capacitor; the upper pole plate of the detection capacitor, the lower pole plate of the detection capacitor, the upper pole plate of the reference capacitor and the lower pole plate of the reference capacitor are mutually independently arranged in physical space. The detection capacitor and the reference capacitor are on the same substrate, the process is simpler to implement, and the upper and lower electrode plates of the detection capacitor and the upper and lower electrode plates of the reference capacitor are mutually independent in physical space, so that mutual interference and misoperation are prevented, and the sensitivity of the capacitive pressure sensor is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor device manufacturing, and more specifically, to a capacitive pressure sensor and a manufacturing method thereof. Background Art

[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 categorized by their principle, including strain gauge, piezoresistive, piezoelectric, vibration frequency, and capacitive pressure sensors. MEMS capacitive pressure sensors typically consist of a pressure-sensitive movable electrode and a fixed electrode. By reducing the gap between the movable and fixed electrodes, the sensitivity of the capacitive pressure sensor can be effectively improved.

[0003] The spacing between the plates 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, the present application provides a capacitive pressure sensor and a manufacturing method thereof, thereby solving the above-mentioned problems.

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

[0006] A support structure, a detection capacitor, and a reference capacitor, wherein 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, the second support structure and the third support structure surround the reference capacitor, and 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 independently arranged in physical space.

[0008] Optionally, it also includes:

[0009] substrate;

[0010] an insulating layer, the insulating layer being located on the substrate;

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

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

[0013] a second conductive 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;

[0014] a third conductive layer, the third conductive layer including a seventh conductive region, the eighth conductive region, and the ninth conductive region;

[0015] The first conductive area is electrically connected to the fourth conductive area and serves as a lower plate of the detection capacitor; the seventh conductive area serves as an upper plate of the detection capacitor, and a first cavity is defined between the seventh conductive area, the fourth conductive area, and the first conductive area;

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

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

[0018] Optionally, the first supporting structure is connected to the third conductive layer in the second supporting structure, the second supporting structure is connected to the third conductive layer in the third supporting structure, and the seventh conductive area is movable.

[0019] Optionally, the second supporting structure is an integrated structure.

[0020] Optionally, the second supporting structure includes at least two parts, and the ninth conductive regions of each part are separated from each other.

[0021] Optionally, it also includes:

[0022] a plurality of first release paths, wherein the first release paths partially penetrate 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;

[0023] A plurality of second release paths are provided, wherein the second release paths penetrate a portion of the fifth conductive region in the reference capacitor, and the second release paths are connected to the first cavity and / or the second cavity to release the sacrificial layer.

[0024] Optionally, it also includes:

[0025] The first conductive area and the fourth conductive area are connected by a first connecting structure, the width of the first connecting structure is smaller than the width of the fourth conductive area after being penetrated, and a seventh release path is formed between adjacent first connecting structures;

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

[0027] Optionally, it also includes:

[0028] A third release path, wherein the third release path passes through part of the third conductive area, the sixth conductive area, and the ninth conductive area in at least one supporting structure, and is connected to 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, the fifth release path is located in the third support structure, the ninth conductive area forming the fourth release path has a first release hole connected to the fourth release path, and the ninth conductive area forming the fifth release path has a second release hole connected to the fifth release path.

[0030] Optionally, the third release path further includes a sixth release path, the sixth release path is located in the second supporting structure, and the ninth conductive area forming the sixth release path has a third release hole connected to the sixth release path.

[0031] Optionally, it also includes:

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

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

[0034] Optionally, it also includes:

[0035] A passivation layer is 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 release path, the fifth release path, the seventh release path and the eighth release path between the first conductive layer and the second conductive layer.

[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 supporting structure, the seventh conductive region is also connected to the first supporting structure, and the eighth conductive region is also connected to the third supporting structure.

[0041] Optionally, it also includes:

[0042] A first conductive contact is connected to the first supporting structure or the third supporting structure.

[0043] Optionally, it also includes:

[0044] a second conductive contact connected to the first conductive region;

[0045] A third conductive contact is connected to the second conductive region.

[0046] Optionally, the number of cells of the capacitive pressure sensor is 2n, 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, the first capacitive pressure sensor unit and the second capacitive pressure sensor unit form a Wheatstone bridge, the first capacitive pressure sensor unit includes a detection capacitor of the first capacitive pressure sensor unit and a reference capacitor of the first capacitive pressure sensor unit, and the second capacitive pressure sensor unit includes a detection capacitor of the second capacitive pressure sensor unit and a reference capacitor of the second capacitive pressure sensor unit.

[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, and 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 of the reference capacitor 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 of the detection capacitor 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 the present 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 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.

[0054] Optionally, it also includes:

[0055] forming an insulating layer on the substrate;

[0056] forming a stop layer on the insulating layer;

[0057] forming a first conductive layer on the stop layer, wherein the first conductive layer includes a first conductive region, a second conductive region, and a third conductive region that are independent of each other;

[0058] forming a first sacrificial layer on the first conductive layer;

[0059] forming a second conductive layer on the first sacrificial layer, wherein the second conductive layer includes a fourth conductive region, a fifth conductive region, and a sixth conductive region that are independent of each other;

[0060] forming a second sacrificial layer and a third sacrificial layer stacked in sequence on the second conductive layer;

[0061] forming a third conductive layer on the third sacrificial layer, wherein the third conductive layer includes a seventh conductive region, the eighth conductive region, and the ninth conductive region;

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

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

[0064] removing at least a portion of the second sacrificial layer and the third sacrificial layer 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, part of the sixth conductive region, and the ninth conductive region are electrically connected and serve as the supporting structure.

[0066] Optionally, the first supporting structure is connected to the third conductive layer in the second supporting structure, the second supporting structure is connected to the third conductive layer in the third supporting structure, and the seventh conductive area is movable.

[0067] Optionally, the second supporting structure is an integrated structure.

[0068] Optionally, the second supporting structure includes at least two parts, and the ninth conductive regions of each part are separated from each other.

[0069] Optionally, it also includes:

[0070] forming a plurality of first release paths, wherein the first release paths partially penetrate 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, wherein the second release paths penetrate a portion of the fifth conductive region in the reference capacitor, and the second release paths are connected to the first cavity and / or the second cavity to release the sacrificial layer.

[0072] Optionally, it also includes:

[0073] forming a first connection structure and a second connection structure, wherein the first conductive region and the fourth conductive region are connected via the first connection structure, wherein the width of the first connection structure is smaller than the width of the fourth conductive region after the connection is established, and the second conductive region and the fifth conductive region are connected via the second connection structure, wherein the width of the second connection structure is smaller than the width of the fifth conductive region after the connection is established;

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

[0075] Optionally, it also includes:

[0076] A third release path is formed, which runs through part of the third conductive area, the sixth conductive area, and the ninth conductive area in at least one supporting structure and is connected to 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, the fifth release path is located in the third support structure, the ninth conductive area forming the fourth release path has a first release hole connected to the fourth release path, and the ninth conductive area forming the fifth release path has a second release hole connected to the fifth release path.

[0078] Optionally, the third release path further includes a sixth release path, the sixth release path is located in the second supporting structure, and the ninth conductive area forming the sixth release path has a third release hole connected to the sixth release path.

[0079] Optionally, it also includes:

[0080] forming a sealing layer over 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,

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

[0082] Optionally, it also includes:

[0083] A passivation layer is formed over the sealing layer.

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

[0085] Optionally, it also includes:

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

[0087] Optionally, it also includes:

[0088] forming a second conductive contact connected to the first conductive region;

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

[0090] Optionally, the number of cells of the capacitive pressure sensor is 2n, 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, the first capacitive pressure sensor unit and the second capacitive pressure sensor unit form a Wheatstone bridge, the first capacitive pressure sensor unit includes a detection capacitor of the first capacitive pressure sensor unit and a reference capacitor of the first capacitive pressure sensor unit, and the second capacitive pressure sensor unit includes a detection capacitor of the second capacitive pressure sensor unit and a reference capacitor of the second capacitive pressure sensor unit.

[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, and 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 of the reference capacitor 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 of the detection capacitor 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 by the present application are characterized in that the detection capacitor and reference capacitor in the capacitive pressure sensor cell are formed on the same substrate, which simplifies the process implementation. Furthermore, the support structure in the capacitive pressure sensor cell 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, which can prevent mutual interference and malfunction.

[0098] Furthermore, the capacitive pressure sensor also includes a grid-shaped second conductive layer, a plurality of first release paths that penetrate part of the fourth conductive area in the second conductive layer, and a plurality of second release paths that penetrate part of the fifth conductive area in the second conductive layer, which are connected to the first cavity and / or the second cavity to release the sacrificial layer. The release efficiency of the sacrificial layer can be improved and the difficulty of releasing the sacrificial layer can be reduced, so that the sensitivity of the capacitive pressure sensor can be improved by reducing the distance between the plates. Furthermore, the capacitive pressure sensor also includes a first connection structure that connects the first conductive area of the first conductive layer and the fourth conductive area of the second conductive layer, and a second connection structure that connects the second conductive area of the first conductive layer and the fifth conductive area of the second conductive layer. The width of the first connection structure is smaller than the width of the fourth conductive area after penetration, and the width of the second connection structure is smaller than the width of the fifth conductive area 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 to further improve the release efficiency of the sacrificial layer and reduce the difficulty of releasing the sacrificial layer.

[0099] Furthermore, the capacitive pressure sensor includes a third release path connected to the first cavity and / or the second cavity to release the sacrificial layer in the capacitive pressure sensor, and a release hole extending through the ninth conductive region of the third conductive layer and connected to the corresponding third release path. Furthermore, the release hole is located in the support structure (i.e., at the edge of the capacitive pressure sensor), and the sealing layer seals the release hole. This reduces the impact of the sealing layer on the enclosed cavities within the detection capacitor and the reference capacitor, further improving the reliability of the capacitive pressure sensor.

[0100] Furthermore, the capacitive pressure sensor provided herein 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 that comprise the Wheatstone bridge have similar structures and can be obtained simultaneously during the manufacturing process without the need for additional material layers, thus reducing manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0102] Figure 1 A schematic plan view of a capacitive pressure sensor according to an embodiment of the present application is shown.

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

[0104] Figure 3a The capacitive pressure sensor of the embodiment of the present application is shown along Figure 1 A schematic diagram of a cross section taken along line A1.

[0105] Figure 3b The capacitive pressure sensor of the embodiment of the present application is shown along Figure 1 Another cross-sectional diagram taken along line A1.

[0106] Figure 3c The capacitive pressure sensor of the embodiment of the present application is shown along Figure 1 A schematic diagram of a cross section taken along line A2.

[0107] Figure 4 A schematic plan view of the second conductive layer in the capacitive pressure sensor according to an embodiment of the present application is shown.

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

[0109] Figures 6a to 6i The cross-sectional views at various stages of a method for manufacturing a capacitive pressure sensor according to an embodiment of the present application are shown. DETAILED DESCRIPTION

[0110] The present application will be described in more detail below with reference to the accompanying drawings. Like reference numerals are used throughout the various figures to represent identical elements. For clarity, parts in the figures are not drawn to scale. Furthermore, certain well-known components may not be shown. For simplicity, a semiconductor device obtained after several steps may be depicted in a single figure.

[0111] Many specific details of the present application are described below, such as device structure, materials, dimensions, processing techniques, and technologies, to provide a clearer understanding of the present application. However, as will be appreciated by those skilled in the art, the present application may be implemented without following these specific details.

[0112] The current sacrificial layer release technology is to set a sacrificial layer release opening on the surface of the pressure-sensitive movable electrode. In the subsequent sealing process, it often brings problems 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 embodied in various forms, some examples of which are described below.

[0114] Figure 1 A schematic plan view of a capacitive pressure sensor according to an embodiment of the present application is shown. Figure 2 A schematic diagram of an equivalent circuit of a capacitive pressure sensor according to an embodiment of the present application is shown. Figure 3aThe capacitive pressure sensor of the embodiment of the present application is shown along Figure 1 A schematic diagram of a cross section taken along line A1. Figure 3b The capacitive pressure sensor of the embodiment of the present application is shown along Figure 1 Another cross-sectional diagram taken along line A1. Figure 3c The capacitive pressure sensor of the embodiment of the present application is shown along Figure 1 A schematic diagram of a cross section taken along line A2.

[0115] The capacitive pressure sensor provided in the present application includes a plurality of capacitive pressure sensor cells. Further, the number of the capacitive pressure sensor cells is 2n, where n is a positive integer greater than or equal to 1. Exemplarily, 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, each of the first capacitive pressure sensor unit 10 and the second capacitive pressure sensor unit 20 includes one capacitive pressure sensor cell. The first capacitive pressure sensor unit 10 includes a detection capacitor Cm-1 of the first capacitive pressure sensor unit and a reference capacitor Cref-1 of the first capacitive pressure sensor unit, and the second capacitive pressure sensor unit 20 includes a detection capacitor Cm-2 of the second capacitive pressure sensor unit and a reference capacitor Cref-2 of the second capacitive pressure sensor unit.

[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, and 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 embodiment of the present application proposes that the upper plate of the detection capacitor in the same capacitive pressure sensor cell is connected to the upper plate of the reference capacitor, and the lower plate of the detection capacitor in an adjacent capacitive pressure sensor cell is connected to the lower plate of the reference capacitor in another capacitive pressure sensor cell. This is only one embodiment of the present application. In the present application, it is also possible to connect the lower plate of the detection capacitor in the same capacitive pressure sensor cell to the lower plate of the reference capacitor, and connect the upper plate of the detection capacitor in an adjacent capacitive pressure sensor cell to the upper plate of the reference capacitor in another capacitive pressure sensor cell (for example, the same capacitive pressure sensor cell includes a reference capacitor Cref-1 and a detection capacitor Cm-2, or includes a reference capacitor Cref-2 and a detection capacitor Cm-1, and correspondingly, 2n capacitive pressure sensor cells are arranged in parallel).

[0120] Figure 3a A cross-sectional diagram of a capacitive pressure sensor cell is shown in FIG. Figure 3b Another cross-sectional diagram of a capacitive pressure sensor cell is shown in FIG. Figure 3c A cross-sectional diagram illustrating 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, while the second support structure 113b and the third support structure 113c 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.

[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 a first conductive region 401a, a second conductive region 401b, and a third conductive region 401c that are independent of each other; a second conductive layer 601, including a fourth conductive region 601a, a fifth conductive region 601b, and a sixth conductive region 601c that are independent of each other; and a third conductive layer 901, including a seventh conductive region 901a, an eighth conductive region 901b, and a ninth conductive region 901c.

[0123] The first conductive region 401a is electrically connected to the fourth conductive region 601a and serves as the lower plate of the detection capacitor. The seventh conductive region 901a serves as the upper plate of the detection capacitor. A first cavity 121 is defined 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 plate of the reference capacitor. The eighth conductive region 901b serves as the upper plate of the reference capacitor. A second cavity 122 is defined 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.

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

[0125] Furthermore, the second support structure 113b is a one-piece structure. Exemplarily, the second support structure 113b includes at least two parts, and the ninth conductive region 901c of each part is separated from each other. Furthermore, the separated ninth conductive regions 901c in the second support structure 113b are connected via the third conductive layer 401c below the sixth conductive region 601c to which they are connected. The seventh conductive region 901a and the eighth conductive region 901b are connected via the indirectly connected ninth conductive region 901c in the second support structure 113b, thereby connecting the top plate of the detection capacitor and the top plate of the reference capacitor in the same capacitive pressure sensor cell.

[0126] Furthermore, the capacitive pressure sensor cell includes a plurality of first release paths 141 and a plurality of second release paths 142. The first release paths 141 partially penetrate the fourth conductive region 601a and communicate with the first cavity 121 and / or the second cavity 122 to release the sacrificial layer. The second release paths 142 partially penetrate the fifth conductive region 601b in the reference capacitor and communicate 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 connection structure 111, a second connection 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 connection structure 111. The width of the first connection structure is smaller than the width of the fourth conductive region 601a after the connection is established. The seventh release path 147 is formed between adjacent first connection structures 111. The second conductive region 401b and the fifth conductive region 601b are connected by the second connection structure 112. The width of the second connection structure 112 is smaller than the width of the fifth conductive region 601b after the connection is established. The eighth release path 148 is formed between adjacent second connection structures 112.

[0128] Furthermore, the capacitive pressure sensor cell also includes a third release path 143, which passes through part of the third conductive area 401c, the sixth conductive area 601c, and the ninth conductive area 901c in at least one supporting structure, and is connected to 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 on the first support structure 113a, the fifth release path 145 is located on the third support structure 113c, and the sixth release path is located on the second support structure 113b. The ninth conductive region 901c forming the fourth release path 144 has a first release hole 151 connected to the fourth release path 144, the ninth conductive region 901c forming the fifth release path 145 has a second release hole 152 connected to the fifth release path 145, and the ninth conductive region 901c forming the sixth release path 146 has a third release hole 153 connected to 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 in 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 further 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, and at least a portion of the first sacrificial layer 501 is 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 further 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 . At least a portion of the second sacrificial layer 701 and the third sacrificial layer 801 are removed to form the first cavity 121 and the 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. The eighth conductive region 901b is also connected to the third support structure 113c.

[0135] Furthermore, the capacitive pressure sensor cell further 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. The second conductive contact C is directly connected to the first conductive region 401a of the capacitive pressure sensor cell or indirectly connected to the first conductive region 401a of the capacitive pressure sensor cell via the first conductive region 401a of another capacitive pressure sensor cell, and / or the third conductive contact E is directly connected to the second conductive region 401b of the capacitive pressure sensor cell or indirectly connected to the first conductive region 401a of the capacitive pressure sensor cell via the second conductive region 401b of another capacitive pressure sensor cell.

[0136] Furthermore, the distance between the upper plate of the reference capacitor and the lower plate of the reference capacitor is limited by the thickness of the second sacrificial layer 701. The distance between the upper plate of the detection capacitor and the lower plate of the detection capacitor is limited by the sum of the thicknesses of the second sacrificial layer 701 and the third sacrificial layer 801. Furthermore, during the manufacturing process, the capacitance of the detection capacitor and the reference capacitor can be adjusted by adjusting the thickness 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 capacitive pressure sensor cell shown is Figure 3a The difference between the capacitive pressure sensor cell in the embodiment of the present invention lies in the third release path and the second support structure.

[0138] like Figure 3b As shown, the second support structure 113b is an integrated structure. Exemplarily, the seventh conductive region 901a and the eighth conductive region 901b are connected via the ninth conductive region 901c in the second support structure 113b, thereby achieving 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 on the first support structure 113a, and the fifth release path 145 is located on the third support structure 113c. The ninth conductive region 901c forming the fourth release path 144 has a first release hole 151 connected to the fourth release path 144, while the ninth conductive region 901c forming the fifth release path 145 has a second release hole 152 connected to 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 a third terminal C. Furthermore, the second conductive region 401b of the capacitive pressure sensor cell 10 is connected to the first conductive region 401a of the capacitive pressure sensor cell 20 via the third conductive region 401c of the second support structure 113b of the capacitive pressure sensor cell 10 and the capacitive pressure sensor cell 20. A conductive contact is drawn through the third support structure 113c of the capacitive pressure sensor cell 10, which is connected to the second conductive region 401b, to form a third terminal C. The seventh conductive region 901a of the capacitive pressure sensor cell 20 is drawn through the first support structure 113a to form a fourth terminal F. The eighth conductive region 901b of the capacitive pressure sensor cell 10 is drawn through a corresponding support structure to form a conductive contact (not shown) to form a first terminal D.

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

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

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

[0144] Furthermore, substrate 100 includes a first surface and a second surface facing each other. An isolation layer and a first conductive layer 401 are sequentially formed on the first surface of substrate 100. The isolation layer electrically isolates the first conductive layer 401 from substrate 100. Exemplarily, the isolation layer includes an insulating layer 201 located on the first surface of 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 a first conductive region 401a, a second conductive region 401b, and a third conductive region 401c that are independent of each other.

[0145] For example, in the crystal direction <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. A stop layer 301 is then 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 cutoff layer for releasing the sacrificial layer in the capacitive pressure sensor. Then, 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 mutually independent first conductive regions 401a, second conductive regions 401b, and third conductive regions 401c. 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 further includes a first through hole 502 penetrating the first sacrificial layer 501 and reaching 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, for example, low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition (PECVD), and the silicon dioxide layer is photolithographically and etched to form a first sacrificial layer 501. The first sacrificial layer 501 includes a first through hole 502 that reaches the surface of the first conductive layer 401.

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

[0150] Furthermore, 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 some 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 with the sixth conductive region 601c of the second conductive layer 601. Furthermore, the second conductive layer 601 also includes a second through hole 502 that penetrates the second conductive layer 601 and reaches 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 conductive layers, each row including, for example, 5 block conductive layers. In an alternative embodiment, see Figure 5 The second conductive layer 601 shown, the fourth conductive region 601a includes multiple rows of block-shaped conductive layers, each row, for example, including one block-shaped conductive layer, thereby increasing the effective area of the lower plate of the detection capacitor. Furthermore, the width of the second through hole 602 is 0.3μm to 1.0μm. The thickness of the second conductive layer 601 is 1.0 to 3.0μm. Furthermore, the width of the second through hole 602 matches the thickness of the second through hole 602, so that the second through hole 602 has a relatively high aspect ratio. Exemplarily, the aspect ratio of the second through hole 602 is approximately 3.

[0151] Exemplarily, a conductive material layer is deposited on the surface of the first sacrificial layer 501 and within the first through-hole 502. The conductive material layer is then photolithographically and etched to form a plurality of second through-holes 602 that penetrate the conductive material layer and reach the surface of the first sacrificial layer 501. The second through-holes 602 mesh the conductive material layer on the surface of the first sacrificial layer 501 and within the first through-holes 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 to 3.0 μm. The width of the second through-hole 602 is 0.3 μm to 1.0 μm. The thickness of the second conductive layer 601 is 1.0 to 3.0 μm. Furthermore, the width of the second through-hole 602 matches its thickness, resulting in a relatively high aspect ratio for the second through-hole 602. Exemplarily, the aspect ratio of the second through hole 602 is approximately 3, for example.

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

[0153] Then, a second sacrificial layer 701 and a third sacrificial layer 801 are sequentially stacked 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 second conductive layer 601 and the surface of the first sacrificial layer 501 exposed through the second through-holes 602, a plurality of first release paths 141 and a plurality of second release paths 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 through-hole 702 that reaches 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, using low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition (PECVD). Because the second through-hole 602 has a high aspect ratio, the silicon dioxide layer does not completely fill the second through-hole 602. Consequently, a plurality of first release paths 141 and a plurality of second release paths 142 are formed 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. The second sacrificial layer 701 also includes a third through-hole 702 that reaches the surface of the fifth conductive region 601b of the second conductive layer 601. The third through-hole 702 is subsequently used to define the distance between the upper and lower plates of the reference capacitor.

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

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

[0159] Exemplarily, the second sacrificial layer 701 is etched by photolithography, and the remaining conductive material layer at the bottom is further isotropically etched 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 the corrosion gas / liquid and the reaction products when the sacrificial layer is subsequently released.

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

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

[0162] Exemplarily, 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). The silicon dioxide layer is then photolithographically and etched to form a third sacrificial layer 801 and a fourth through hole 802 located in the support region and extending through the second and third sacrificial layers 701, 801, to the surface of the sixth conductive region 601c of the second conductive layer 601. The fourth through hole 802 is used for the subsequent formation of a 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 third sacrificial layer 801 and the surface of the second conductive layer 601 exposed through the fourth through hole 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] For example, a conductive material layer is deposited on the third sacrificial layer 801 and the surface of the second conductive layer 601 exposed through the fourth through-hole 802, for example, by low-pressure chemical vapor deposition (LPCVD) or epitaxy. This conductive material layer is then photolithographically and etched to form the seventh conductive region 901a, the eighth conductive region 901b, and the ninth conductive region 901c. A first release hole 151, a second release hole 152, and a third release hole 153 are also 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, which is exposed in the fourth through-hole 802, is then filled to form a support structure.

[0166] Furthermore, the seventh conductive region 901 a serves as an upper plate of the detection capacitor, and the eighth conductive region 901 b serves as an upper plate 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] Illustratively, selective wet etching with 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 (for example, 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. The first sacrificial layer 501, the second sacrificial layer 701, and the third sacrificial layer 801 are then released through the above-mentioned release paths to form the first cavity 121 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, while the second support structure 113b and the third support structure 113c surround the reference capacitor.

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

[0170] Then as Figure 3a As shown, a sealing layer 1001 is formed on a portion of the surface 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 in the vertical direction, while the peripheral portion of the sealing layer 1001 restricts the movement of the eighth conductive region 901b and the ninth conductive region 901c in the vertical direction.

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

[0173] Exemplarily, 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 first release hole 151, second release hole 152, and 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. Furthermore, the pressure within the closed cavity is, for example, 100 mTorr to 5 Torr. Specifically, sealing layer 1001 may be a silicon dioxide layer, a silicon nitride layer, or a borosilicate glass (BPSG) layer. The thickness of sealing layer 1001 is 1.0 μm to 4.0 μm.

[0174] The sealing layer 1001 is then photolithographically etched to form lead holes. A metal layer is then 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, aluminum silicon (Al-Si1%), or Ti+TiN+Al-Si. The thickness of the conductive contacts is generally 0.5μm to 2μm.

[0175] Then, a plasma enhanced chemical vapor deposition (PECVD) method and patterning are used to form a passivation layer 1201 . The passivation layer 1201 may 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 by the present application are characterized in that the detection capacitor and reference capacitor in the cell of the capacitive pressure sensor are formed on the same substrate, which simplifies the process implementation. 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 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, which can prevent mutual interference and malfunction.

[0177] Furthermore, the capacitive pressure sensor also includes a grid-shaped second conductive layer, a plurality of first release paths that penetrate part of the fourth conductive area in the second conductive layer, and a plurality of second release paths that penetrate part of the fifth conductive area in the second conductive layer, which are connected to the first cavity and / or the second cavity to release the sacrificial layer. The release efficiency of the sacrificial layer can be improved and the difficulty of releasing the sacrificial layer can be reduced, so that the sensitivity of the capacitive pressure sensor can be improved by reducing the distance between the plates. Furthermore, the capacitive pressure sensor also includes a first connection structure that connects the first conductive area of the first conductive layer and the fourth conductive area of the second conductive layer, and a second connection structure that connects the second conductive area of the first conductive layer and the fifth conductive area of the second conductive layer. The width of the first connection structure is smaller than the width of the fourth conductive area after penetration, and the width of the second connection structure is smaller than the width of the fifth conductive area 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 to further improve the release efficiency of the sacrificial layer and reduce the difficulty of releasing the sacrificial layer.

[0178] Furthermore, the capacitive pressure sensor includes a third release path connected to the first cavity and / or the second cavity to release the sacrificial layer in the capacitive pressure sensor, and a release hole extending through the ninth conductive region of the third conductive layer and connected to the corresponding third release path. Furthermore, the release hole is located in the support structure (i.e., at the edge of the capacitive pressure sensor), and the sealing layer seals the release hole. This reduces the impact of the sealing layer on the enclosed cavities within the detection capacitor and the reference capacitor, further improving the reliability of the capacitive pressure sensor.

[0179] Furthermore, the capacitive pressure sensor provided herein 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 that comprise the Wheatstone bridge have similar structures and can be obtained simultaneously during the manufacturing process without the need for additional material layers, thus reducing manufacturing costs.

[0180] In the above description, the technical details of patterning and etching of each layer are not described in detail. However, those skilled in the art will understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, those skilled in the art may also design methods that are not identical to the methods described above to form the same structure. In addition, although each embodiment is described separately above, this does not mean that the measures in each embodiment cannot be used in combination to advantage.

[0181] The above describes the embodiments of the present application. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this application. The scope of this application is defined by the appended claims and their equivalents. Without departing from the scope of this application, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of this application.

Claims

1. A capacitive pressure sensor, characterized in that: The device comprises a plurality of capacitive pressure sensor cells, wherein the capacitive pressure sensor cells include: A support structure, a detection capacitor, and a reference capacitor, wherein 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, the second support structure and the third support structure surround the reference capacitor, and 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 independently arranged in physical space.

2. The capacitive pressure sensor according to claim 1, wherein: Also includes: substrate; an insulating layer, the insulating layer being located on the substrate; a stop layer, the stop layer being located on the insulating layer; a first conductive layer, the first conductive layer comprising a first conductive area, a second conductive area, and a third conductive area that are independent of each other; a second conductive 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; a third conductive layer, the third conductive layer including a seventh conductive region, the eighth conductive region, and the ninth conductive region; The first conductive area is electrically connected to the fourth conductive area and serves as the lower plate of the detection capacitor; The seventh conductive area serves as the upper plate of the detection capacitor, and a first cavity is defined between the seventh conductive area, the fourth conductive area, and the first conductive area; The second conductive region is electrically connected to the fifth conductive region and serves as a lower plate of the reference capacitor; The eighth conductive region serves as an upper plate of the reference capacitor, and a second cavity is defined between the eighth conductive region, the fifth conductive region, and the second conductive region; The third conductive region, part 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, wherein: The first supporting structure is connected to the third conductive layer in the second supporting structure, the second supporting structure is connected to the third conductive layer in the third supporting structure, and the seventh conductive area is movable.

4. The capacitive pressure sensor according to claim 3, wherein: The second supporting structure is an integrated structure.

5. The capacitive pressure sensor according to claim 4, characterized in that: The second supporting structure includes at least two parts, and the ninth conductive regions of each part are separated from each other.

6. The capacitive pressure sensor according to claim 2, characterized in that: Also includes: a plurality of first release paths, wherein the first release paths partially penetrate 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 provided, wherein the second release paths penetrate a portion of the fifth conductive region in the reference capacitor, and the second release paths are connected to 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 area and the fourth conductive area are connected by a first connecting structure, the width of the first connecting structure is smaller than the width of the fourth conductive area after being penetrated, and a seventh release path is formed between adjacent first connecting structures; The second conductive area and the fifth conductive area are connected via a second connecting structure. The width of the second connecting structure is smaller than the width of the fifth conductive area after being penetrated. 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, wherein the third release path passes through part of the third conductive area, the sixth conductive area, and the ninth conductive area in at least one supporting structure, and is connected to 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, the fifth release path is located in the third support structure, the ninth conductive area forming the fourth release path has a first release hole connected to the fourth release path, and the ninth conductive area forming the fifth release path has a second release hole connected to the fifth release path.

10. The capacitive pressure sensor according to claim 8, characterized in that: The third release path further includes a sixth release path, the sixth release path is located in the second supporting structure, and the ninth conductive region forming the sixth release path has a third release hole communicating with the sixth release path.

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

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

13. The capacitive pressure sensor according to claim 9, wherein: 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 release path, the fifth release path, the seventh release path and the eighth release path between the first conductive layer and the second conductive layer.

14. The capacitive pressure sensor according to claim 2, wherein: 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, wherein: The seventh conductive region and the eighth conductive region are connected to the ninth conductive region in the second supporting structure. The seventh conductive region is also connected to the first supporting structure. The eighth conductive region is also connected to the third supporting structure.

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

17. The capacitive pressure sensor according to claim 2, wherein: Also includes: a second conductive contact connected to the first conductive region; A third conductive contact is connected to the second conductive region.

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

19. The capacitive pressure sensor according to claim 18, wherein: The 2n capacitive pressure sensor cells are arranged side by side.

20. The capacitive pressure sensor according to claim 18, wherein: The capacitive pressure sensor includes a first capacitive pressure sensor unit and a second capacitive pressure sensor unit, wherein the first capacitive pressure sensor unit and the second capacitive pressure sensor unit form a Wheatstone bridge, wherein the first capacitive pressure sensor unit includes a detection capacitor of the first capacitive pressure sensor unit and a reference capacitor of the first capacitive pressure sensor unit, and the second capacitive pressure sensor unit includes a detection capacitor of the second capacitive pressure sensor unit and a reference capacitor of the second capacitive pressure sensor unit. 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, and 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, wherein: The distance between the upper plate of the reference capacitor and the lower plate of the reference capacitor is limited by the thickness of the second sacrificial layer.

22. The capacitive pressure sensor according to claim 14, wherein: The distance between the upper plate of the detection capacitor 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 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.

24. The method for manufacturing a capacitive pressure sensor according to claim 23, wherein: Also includes: forming an insulating layer on the substrate; forming a stop layer on the insulating layer; forming a first conductive layer on the stop layer, wherein the first conductive layer includes a first conductive region, a second conductive region, and a third conductive region that are independent of each other; forming a first sacrificial layer on the first conductive layer; forming a second conductive layer on the first sacrificial layer, wherein the second conductive layer includes a fourth conductive region, a fifth conductive region, and a sixth conductive region that are independent of each other; forming a second sacrificial layer and a third sacrificial layer stacked in sequence on the second conductive layer; forming a third conductive layer on the third sacrificial layer, wherein the third conductive layer includes a seventh conductive region, the eighth conductive region, and the ninth conductive region; The first conductive area is electrically connected to the fourth conductive area and serves as the lower plate of the detection capacitor; the seventh conductive area serves as the upper plate of the detection capacitor; The second conductive region is electrically connected to the fifth conductive region and serves as a lower plate of the reference capacitor; The eighth conductive region serves as the upper plate of the reference capacitor; removing at least a portion of the second sacrificial layer and the third sacrificial layer 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, part 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, wherein: The first supporting structure is connected to the third conductive layer in the second supporting structure, the second supporting structure is connected to the third conductive layer in the third supporting structure, and the seventh conductive area is movable.

26. The method for manufacturing a capacitive pressure sensor according to claim 25, wherein: The second supporting structure is an integrated structure.

27. The method for manufacturing a capacitive pressure sensor according to claim 26, wherein: The second supporting structure includes at least two parts, and the ninth conductive regions of each part are separated from each other.

28. The method for manufacturing a capacitive pressure sensor according to claim 25, wherein: Also includes: forming a plurality of first release paths, wherein the first release paths partially penetrate 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, wherein the second release paths penetrate a portion of the fifth conductive region in the reference capacitor, and the second release paths are connected to 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, wherein: Also includes: forming a first connection structure and a second connection structure, wherein the first conductive region and the fourth conductive region are connected via the first connection structure, wherein the width of the first connection structure is smaller than the width of the fourth conductive region after the connection is established, and the second conductive region and the fifth conductive region are connected via the second connection structure, wherein the width of the second connection structure is smaller than the width of the fifth conductive region after the connection is established; At least a portion of the first sacrificial layer is removed to form a seventh release path between adjacent first connection structures and an eighth release path between adjacent second connection structures.

30. The method for manufacturing a capacitive pressure sensor according to claim 28 or 29, wherein: Also includes: A third release path is formed, which runs through part of the third conductive area, the sixth conductive area, and the ninth conductive area in at least one supporting structure and is connected to 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, wherein: 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, the fifth release path is located in the third support structure, the ninth conductive area forming the fourth release path has a first release hole connected to the fourth release path, and the ninth conductive area forming the fifth release path has a second release hole connected to the fifth release path.

32. The method for manufacturing a capacitive pressure sensor according to claim 30, wherein: The third release path further includes a sixth release path, the sixth release path is located in the second supporting structure, and the ninth conductive region forming the sixth release path has a third release hole communicating with the sixth release path.

33. The method for manufacturing a capacitive pressure sensor according to claim 24, wherein: Also includes: forming a sealing layer over 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 of the sealing layer allows the seventh conductive region to move along the vertical direction, and the peripheral portion of the sealing layer restricts the movement of the eighth conductive region and the ninth conductive region along the vertical direction.

34. The method for manufacturing a capacitive pressure sensor according to claim 33, wherein: Also includes: A passivation layer is formed over the sealing layer.

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

36. The method for manufacturing a capacitive pressure sensor according to claim 35, wherein: Also includes: A first conductive contact is formed, which 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, wherein: Also includes: forming a second conductive contact connected to the first conductive region; A third conductive contact is formed, wherein the third conductive contact is connected to the first conductive region.

38. The method for manufacturing a capacitive pressure sensor according to any one of claims 23 to 29, wherein: The number of cells of the capacitive pressure sensor is 2n, 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, wherein: The 2n capacitive pressure sensor cells are arranged side by side.

40. The method for manufacturing a capacitive pressure sensor according to claim 38, wherein: The capacitive pressure sensor includes a first capacitive pressure sensor unit and a second capacitive pressure sensor unit, wherein the first capacitive pressure sensor unit and the second capacitive pressure sensor unit form a Wheatstone bridge, wherein the first capacitive pressure sensor unit includes a detection capacitor of the first capacitive pressure sensor unit and a reference capacitor of the first capacitive pressure sensor unit, and the second capacitive pressure sensor unit includes a detection capacitor of the second capacitive pressure sensor unit and a reference capacitor of the second capacitive pressure sensor unit. 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, and 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, wherein: The distance between the upper plate of the reference capacitor and the lower plate 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, wherein: The distance between the upper plate of the detection capacitor 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, wherein: 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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