Manufacturing method of absolute pressure type sensor and absolute pressure type sensor structure

Abstract

The invention provides a manufacturing method of an absolute pressure sensor and an absolute pressure sensor structure, and the method comprises the steps: firstly, etching a plurality of release holes in a first passivation layer on the surface of a substrate, and then carrying out the wet etching of the substrate through the plurality of release holes, so as to form an initial cavity; a first deposition layer is formed on the first passivation layer to seal the initial cavity, and a sealed cavity is formed; and finally, manufacturing a device region on the first deposition layer to form an absolute pressure type sensor. According to the method provided by the invention, the depth of the initial cavity can be controlled on the basis of saving the cost and avoiding the problem of poor alignment precision of the sealed cavity and the device region, so that more absolute pressure type sensors with different performance requirements can be manufactured.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor device manufacturing, and in particular to a manufacturing method and structure of an absolute pressure sensor. Background Art

[0002] The absolute pressure sensor is a common MEMS pressure sensor. Its main functional structure is a sealed cavity. The sealed cavity can be made into a normal pressure sealed cavity or a high vacuum sealed cavity according to the practical scenario of the sensor.

[0003] There are two main methods for making a sealed cavity for a MEMS pressure sensor in the prior art:

[0004] The first method is to use a bonding process route, first etching a cavity on the first wafer, and then bonding the cavity wafer to the second wafer to form a sealed cavity. However, the problem with this method is that it requires the use of two wafers, which makes the production cost relatively high, and the final product is thicker. In addition, this method involves front and back lithography when making the device area, which will result in poor alignment accuracy between the sealed cavity and the device area, thereby affecting product performance.

[0005] The second method is to use the cavity-on-silicon process route, first forming a porous structure on the surface of the wafer, and then forming a sealed cavity structure through the self-migration of silicon at high temperature. However, the problem with this method is that the cavity-on-silicon process is complicated and cannot form a sealed cavity with a depth greater than 10 microns, which will affect the final performance of the absolute pressure sensor.

[0006] Therefore, providing a method for manufacturing an absolute pressure sensor that can reduce manufacturing costs, eliminate the problem of alignment accuracy between the sealed cavity and the device area, and control the depth of the sealed cavity has become a technical problem that the industry urgently needs to solve. Summary of the invention

[0007] The present invention provides a manufacturing method of an absolute pressure sensor and an absolute pressure sensor structure, so as to solve the problems of high manufacturing cost and shallow sealing cavity formed in the prior art.

[0008] According to a first aspect of the present invention, there is provided a method for manufacturing an absolute pressure sensor, comprising:

[0009] Providing a substrate, wherein the crystal orientation of the substrate is (100);

[0010] Forming a first passivation layer and a second passivation layer on two opposite surfaces of the substrate respectively;

[0011] Forming a plurality of release holes in a preset position area of ​​the first passivation layer, and the release holes penetrate the first passivation layer;

[0012] Wet-etching the substrate through the plurality of release holes to form an initial cavity of a preset depth at a preset cavity position of the substrate, wherein the preset cavity position corresponds to the preset position area;

[0013] forming a first deposition layer on the first passivation layer to seal the initial cavity to form a sealed cavity;

[0014] A device region is formed at a preset device position of the first deposition layer to form an absolute pressure sensor; wherein the preset device position corresponds to the preset cavity position in a vertical direction.

[0015] Optionally, forming a plurality of release holes at preset positions of the first passivation layer specifically includes:

[0016] forming a patterned mask layer on the first passivation layer of the substrate, wherein the patterned mask layer comprises a plurality of release hole patterns;

[0017] The first passivation layer is etched using the patterned mask layer as a mask to form a plurality of release hole patterns in a preset position area of ​​the first passivation layer.

[0018] Optionally, the plurality of release holes are evenly distributed in the preset position area.

[0019] Optionally, the first deposition layer is formed on the surface of the first passivation layer by a chemical vapor deposition process; the pressure of the chemical vapor deposition process is 0.1 Torr-1.0 Torr.

[0020] Optionally, the first deposition layer is formed on the surface of the first passivation layer by an epitaxial process; the pressure of the epitaxial process is 1e -4 Millitorr - 760 Torr.

[0021] Optionally, the first deposition layer is a polysilicon layer.

[0022] Optionally, the thickness of the polysilicon layer is 1 micron-50 microns.

[0023] Optionally, the initial cavity has an inverted terrace shape, and the preset depth is greater than 10 microns.

[0024] Optionally, the wet etching solution is an alkaline etching solution.

[0025] According to a second aspect of the present invention, there is provided an absolute pressure sensor structure, comprising:

[0026] A substrate, wherein the crystal orientation of the substrate is (100);

[0027] A first passivation layer and a second passivation layer, wherein the first passivation layer and the second passivation layer are respectively formed on two opposite surfaces of the substrate;

[0028] A plurality of release holes are formed in a preset position region of the first passivation layer, and the release holes penetrate the first passivation layer; wherein the preset position region corresponds to a preset cavity position;

[0029] A sealed cavity is formed in the preset cavity position area of ​​the substrate, and the sealed cavity is in an inverted terrace shape; wherein the position of the sealed cavity corresponds to the preset position area;

[0030] A first deposition layer, formed on the first passivation layer, the first deposition layer serving as a sealing layer of the sealed cavity;

[0031] A device area is formed at a preset device position in the first deposition layer; the preset device position corresponds to the position of the sealed cavity in a vertical direction.

[0032] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0033] In a method for manufacturing an absolute pressure sensor provided in an embodiment of the present invention, a plurality of release holes are etched in a first passivation layer on a surface of a substrate; then the substrate is wet-etched through the plurality of release holes to form an initial cavity; then a first deposition layer is formed on the first passivation layer to seal the initial cavity to form a sealed cavity; finally, a device area is fabricated on the first deposition layer to form an absolute pressure sensor; so that the embodiment of the present invention only needs to use one substrate to form the sealed cavity, thereby saving fabrication costs; and the embodiment of the present invention avoids the front and back photolithography overlay in the prior art by fabricating the device area on the deposition layer grown on the front side, thereby improving the alignment accuracy between the fabricated sealed cavity and the device area.

[0034] In addition, the embodiment of the present invention can form an initial cavity of any depth through wet etching, so that the depth of the initial cavity can be unrestricted, thereby manufacturing an absolute pressure sensor that meets the product performance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a flow chart of a method for manufacturing an absolute pressure sensor provided by one embodiment of the present invention;

[0036] Figure 2-Figure 8 It is a schematic cross-sectional diagram of a device structure corresponding to each step of a method for manufacturing an absolute pressure sensor provided by an embodiment of the present invention;

[0037] Fig. 9 This is an arrangement of a plurality of release holes provided in one embodiment of the present invention.

[0038] Reference numerals:

[0039] 1- substrate;

[0040] 2- first passivation layer;

[0041] 3- second passivation layer;

[0042] 4-Release hole;

[0043] 5-initial cavity;

[0044] 6-Seal the cavity;

[0045] 7- Sedimentary layer;

[0046] 8-Device area;

[0047] 9- The third passivation layer. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the embodiments in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. The terms "first", "second", "third", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0049] As described in the background technology, in order to complete the production of absolute pressure sensors, the existing technology usually adopts a bonding process route or a cavity-on-silicon process route to form a sealed cavity. However, these two methods have their own disadvantages, namely, the bonding process route has a high production cost and will result in poor alignment accuracy between the sealed cavity and the device area; the cavity-on-silicon process route can only produce a shallower sealed cavity, which affects the performance of the produced absolute pressure sensor.

[0050] In view of this, the present invention creatively proposes a method for manufacturing an absolute pressure sensor, comprising:

[0051] Providing a substrate, wherein the crystal orientation of the substrate is (100);

[0052] Forming a first passivation layer and a second passivation layer on two opposite surfaces of the substrate respectively;

[0053] Forming a plurality of release holes in a preset position area of ​​the first passivation layer, and the release holes penetrate the first passivation layer;

[0054] Wet-etching the substrate through the plurality of release holes to form an initial cavity of a preset depth at a preset cavity position of the substrate, wherein the preset cavity position corresponds to the preset position area;

[0055] forming a first deposition layer on the first passivation layer to seal the initial cavity to form a sealed cavity;

[0056] A device region is formed at a preset device position of the first deposition layer to form an absolute pressure sensor; wherein the preset device position corresponds to the preset cavity position in a vertical direction.

[0057] In the method for manufacturing an absolute pressure sensor provided by the technical solution of the present invention, a plurality of release holes are first etched in the first passivation layer on the surface of the substrate; then the substrate is wet-etched through the release holes to form an initial cavity; then a first deposition layer is formed on the first passivation layer to seal the initial cavity to form a sealed cavity; finally, a device area is formed on the first deposition layer to form an absolute pressure sensor; thus, the present invention can use only one substrate to complete the manufacture of the absolute pressure sensor, thereby saving the manufacturing cost. In addition, in the method provided by the present invention, the initial cavity is formed by etching on the front side, and then the sealed cavity is formed by growing the first deposition layer on the front side, so that the alignment accuracy between the sealed cavity and the device area is improved, thereby solving the problem of poor alignment accuracy between the sealed cavity and the device area caused by the photolithography overlay on the front and back sides in the prior art. And because the initial cavity is formed by wet etching in the method provided by the present invention, there is no limit on the depth of the initial cavity, so that technicians can manufacture the corresponding absolute pressure sensor according to the product performance requirements.

[0058] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0059] in, Figure 1 is a flow chart of a method for manufacturing an absolute pressure sensor provided by one embodiment of the present invention; Figure 2-Figure 8 It is a schematic cross-sectional diagram of a device structure corresponding to each step of a method for manufacturing an absolute pressure sensor provided by an embodiment of the present invention; Fig. 9 This is an arrangement of a plurality of release holes provided in one embodiment of the present invention.

[0060] Please refer to Figure 1 Combined with Figure 2-Figure 8 The manufacturing method of the absolute pressure sensor provided by the embodiment of the present invention may include:

[0061] S1: providing a substrate 1, wherein the crystal orientation of the substrate 1 is (100); Figure 2 shown.

[0062] The substrate 1 is a clean substrate after cleaning to prevent the impurities on the substrate 1 from affecting the subsequent manufacture of the absolute pressure sensor.

[0063] In this embodiment, the substrate 1 is a silicon substrate.

[0064] S2: forming a first passivation layer 2 and a second passivation layer 3 on two opposite surfaces of the substrate 1; Figure 3 shown.

[0065] The materials of the first passivation layer 2 and the second passivation layer 3 may be, for example, silicon nitride or silicon oxide or silicon oxynitride. Of course, those skilled in the art should be aware that the materials of the first passivation layer 2 and the second passivation layer 3 are not limited thereto, and any material that can protect the substrate 1 during wet etching is within the protection scope of the present invention.

[0066] In one embodiment, the thickness of the first passivation layer 2 and the second passivation layer 3 are both 100 nanometers to 2000 nanometers.

[0067] It should be noted that the present invention does not make any requirements on the number of passivation layers on the surface of the substrate 1. As long as the substrate 1 can be protected, the number of passivation layers on any surface of the substrate 1 can be multiple layers, such as two or three layers.

[0068] In one embodiment, the first passivation layer 2 and the second passivation layer 3 are formed by, for example, plasma enhanced chemical vapor deposition, low pressure chemical vapor deposition or thermal oxidation. If plasma enhanced chemical vapor deposition is used, the process temperature is generally about 400°C; if low pressure chemical vapor deposition is used, the process temperature is generally 500°C-700°C; if thermal oxidation is used, the process temperature is generally 80°C-1000°C. Of course, those skilled in the art should be aware that there are many other ways to form the first passivation layer 2 and the second passivation layer 3 and the corresponding process conditions, and the present invention is not limited thereto.

[0069] S3: forming a plurality of release holes 4 in a preset position area of ​​the first passivation layer 2, and the release holes 4 penetrate the first passivation layer 2; Figure 4 shown.

[0070] The preset cavity position may be understood as a sealed cavity formed at this position being vertically opposite to a position of a device region formed subsequently.

[0071] As an implementation mode, S3 may specifically include:

[0072] S31: forming a patterned mask layer on the first passivation layer 2 of the substrate 1, wherein the patterned mask layer includes a plurality of release hole patterns;

[0073] S32 : using the patterned mask layer as a mask, etching the first passivation layer 2 to form a plurality of release holes in the first passivation layer 2 .

[0074] As a specific implementation, step S3 may include:

[0075] S311: spin coating a photoresist layer on the first passivation layer 2 of the substrate 1;

[0076] S312: using a photomask to expose and develop the photoresist layer to achieve patterning of the photoresist layer, thereby forming a patterned photoresist layer; the patterned photoresist layer includes a plurality of release hole patterns;

[0077] S321 : using the patterned photoresist layer as a mask, etching the first passivation layer 2 on the substrate 1 to form a plurality of release holes 4 in the first passivation layer 2 .

[0078] In this embodiment, after step S321 is completed, the following step may further include: removing the remaining patterned photoresist layer.

[0079] In addition, it should be appreciated that the above example uses the material of the first patterned mask layer as photoresist. In actual applications, the patterned mask layer may also be made of other materials and may also be formed in other ways, and the present invention is not limited thereto.

[0080] Preferably, please refer to Figure 8 , the plurality of release holes 4 are evenly distributed in the first passivation layer 2 corresponding to the preset cavity position. The evenly distributed release holes 4 enable the etching liquid in the subsequent wet etching to better contact with the substrate 1, which is beneficial to control the morphology of the sealed cavity 6 formed at the preset cavity position of the substrate 1.

[0081] In one embodiment, the size of the release hole 4 can be, for example, 3 microns to 10 microns. Of course, the present invention is not limited thereto, and the size of the release hole 4 can be set according to actual conditions. Of course, it should be noted that the size of the release hole 4 is positively correlated with the etching rate of the substrate 1, and those skilled in the art can reasonably select the size of the release hole 4 according to the requirements of the etching rate of the substrate 1.

[0082] In one embodiment, the shape of the release hole 4 can be circular, such as Fig. 9 However, it should be appreciated that the release hole 4 may also be in other shapes, such as a square or other irregular shapes, etc., and the present invention is not limited thereto.

[0083] The method for etching the first passivation layer 2 may be wet etching or dry etching, but the present invention is not limited thereto.

[0084] S4: wet-etching the substrate 1 through the plurality of release holes 4 to form an initial cavity 5 of a preset depth at a preset cavity position of the substrate 1, wherein the preset cavity position corresponds to the preset position area; Figure 5 shown.

[0085] In this embodiment, the crystal orientation of the substrate 1 is (100), and an inverted terraced initial cavity 5 can be formed in the substrate 1 by etching with an alkaline etching solution.

[0086] In this embodiment, the formed inverted terraced initial cavity 5 is an inverted terraced initial cavity 5 with an inclined angle of about 54.7° downward.

[0087] In this embodiment, the depth of the initial cavity 5 is greater than 10 micrometers. Those skilled in the art will appreciate that the initial cavity 5 does not penetrate the substrate 1 .

[0088] The formation of the initial cavity 5 is described in detail below through a specific embodiment.

[0089] As a typical example, the size of the opening of the inverted terraced initial cavity 5 is 1×1 mm-2×2 mm, and the depth is about 300 μm-500 μm. Of course, those skilled in the art should realize that the size and depth of the initial cavity 5 formed can also be other values, and the present invention is not limited thereto.

[0090] As an implementation manner, the wet etching solution used when performing the wet etching on the substrate 1 may be, for example, a potassium hydroxide solution or a tetramethylammonium hydroxide solution.

[0091] For example, if the size of the release hole 4 is 3 microns, the number of the release holes 4 is 9, the opening size is 1×1 mm, and the depth is about 300 microns, if a potassium hydroxide solution is used, the solubility of the potassium hydroxide solution is 10%, the temperature of the solution is 80° C., and the etching time is 4 hours to 6 hours. The higher the concentration of the potassium hydroxide solution and the higher the temperature, the faster the etching rate and the shorter the etching time.

[0092] If a tetramethylammonium hydroxide solution is used, the solubility of the tetramethylammonium hydroxide solution is 10%, the temperature of the solution is 90° C., and the etching time is 6 to 8 hours. The lower the concentration of the tetramethylammonium hydroxide solution and the higher the temperature, the faster the etching rate and the shorter the etching time.

[0093] It should be noted that the present invention does not limit the type, concentration, temperature and etching time of the etching solution, and those skilled in the art can select the etching solution, the concentration and temperature of the etching solution and the etching time according to actual conditions.

[0094] In this embodiment, after step S4 is completed, the following steps may be further included: cleaning the substrate 1 and then drying it to remove the residual etching solution and pollutants on the substrate 1, thereby obtaining a clean substrate 1 to avoid affecting subsequent process steps.

[0095] S5: forming a first deposition layer 7 on the first passivation layer 2 to seal the initial cavity 5 to form a sealed cavity 6; Figure 6 shown.

[0096] As an example, the first deposition layer 7 is a polysilicon layer.

[0097] As an embodiment, the first deposition layer 7 is formed on the surface of the first passivation layer 2 by a chemical vapor deposition process, and the process pressure of the chemical vapor deposition is 0.1 Torr-1.0 Torr. Since the pressure of the sealed cavity 6 is the same as the process pressure, the pressure inside the sealed cavity 6 is also 0.1 Torr-1.0 Torr, that is, a high vacuum sealed cavity 6 is formed.

[0098] As another embodiment, the first deposition layer 7 is formed on the surface of the first passivation layer 2 by an epitaxial process, and the pressure of the epitaxial process is 1e -4 mTorr-760Torr. Wherein, when the pressure during the epitaxial growth is 1e -4 Between mTorr and 760 Torr, since the pressure inside the sealed cavity 6 is the same as the process pressure, the pressure inside the sealed cavity 6 is also 1e -4mTorr-760 Torr, that is, forming a high vacuum sealed cavity 6. When the pressure during the epitaxial growth is normal pressure, generally about 760 Torr, since the pressure inside the sealed cavity 6 is the same as the process pressure, the pressure inside the sealed cavity 6 is also normal pressure, that is, forming a normal pressure sealed cavity 6.

[0099] In one example, the thickness of the first deposition layer 7 is 1 micrometer to 50 micrometers.

[0100] In this embodiment, by forming the first deposition layer 7 on the first passivation layer 2 , the first deposition layer 7 can seal the release hole 4 on the first passivation layer 2 , thereby obtaining the sealed cavity 6 .

[0101] S6: forming a device region 8 at a preset device position of the first deposition layer 7 to form an absolute pressure sensor; wherein the preset device position corresponds to the preset cavity position in a vertical direction; Figure 7 shown.

[0102] Among them, S6 may include:

[0103] S61: forming a patterned mask layer on the first deposition layer 7, wherein the patterned mask layer includes a device region pattern;

[0104] S62 : using the patterned mask layer as a mask, performing ion implantation on the first deposition layer 7 to form a device region 8 in the first deposition layer 7 .

[0105] Preferably, please refer to Figure 8 A third passivation layer 9 is formed on the first deposition layer 7 having the device region 8 formed thereon, and the third passivation layer 9 covers the device region 8 to protect the device region 8 in the subsequent manufacture of the absolute pressure sensor.

[0106] The material of the third passivation layer 9 may be silicon nitride, silicon oxide, or silicon oxynitride.

[0107] In summary, the method for manufacturing an absolute pressure sensor provided by the technical solution of the present invention is to first etch a plurality of release holes in the first passivation layer on the surface of the substrate, and then wet-etch the substrate through the release holes to form an initial cavity, and then form a first deposition layer on the first passivation layer to seal the cavity to form a sealed cavity, and finally make a device area on the first deposition layer to form an absolute pressure sensor; thus, the technical solution of the present invention can use only one substrate to complete the manufacture of the absolute pressure sensor, thereby saving the manufacturing cost. In addition, the technical solution of the present invention is to form the initial cavity by etching the front side, and then form the sealed cavity by growing the first deposition layer on the front side, so that the alignment accuracy of the sealed cavity and the device area is improved, thereby solving the problem of poor alignment accuracy between the sealed cavity and the device area caused by the photolithography overlay of the front and back sides in the prior art. And because the technical solution of the present invention forms the initial cavity by wet etching, there is no limit on the depth of the initial cavity, so that technicians can make the corresponding absolute pressure sensor according to the product performance requirements.

[0108] Please refer to Figure 7 The embodiment of the present invention further provides an absolute pressure sensor structure, including:

[0109] A substrate 1, wherein the crystal orientation of the substrate 1 is (100);

[0110] A first passivation layer 2 and a second passivation layer 3, wherein the first passivation layer 2 and the second passivation layer 3 are respectively formed on two opposite surfaces of the substrate 1;

[0111] A plurality of release holes 4 are formed in a preset position area of ​​the first passivation layer 2, and the release holes 4 penetrate the first passivation layer 2;

[0112] A sealed cavity 6 is formed in a preset cavity position of the substrate 1, and the sealed cavity 6 is in an inverted terrace shape; wherein the position of the sealed cavity 6 corresponds to the preset position area;

[0113] A first deposition layer 7 is formed on the first passivation layer 7, and the first deposition layer 7 serves as a sealing layer of the sealed cavity 6;

[0114] The device area 8 is formed at a preset device position in the first deposition layer 7 ; the preset device position corresponds to the position of the sealed cavity 6 in the upper and lower directions.

[0115] Preferably, if Figure 8 As shown, the absolute pressure sensor structure further includes a third passivation layer 9 which is formed on the first deposition layer 7 and covers the device region 8 to protect the device region 8 .

[0116] Among them, the absolute pressure sensor structure provided by the present invention has a sealed cavity formed on the front side of the substrate, which improves the alignment accuracy between the sealed cavity and the device area, thereby solving the problem of poor alignment accuracy between the sealed cavity and the device area caused by front and back photolithography in the prior art.

[0117] The materials, formation process, working principle, specific implementation method and beneficial effects involved in the absolute pressure sensor structure in the embodiment of the present invention can all be found in the manufacturing method of the absolute pressure sensor in the embodiment of the present invention, and will not be repeated here.

[0118] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for manufacturing an absolute pressure sensor, characterized in that: include: Providing a substrate, wherein the crystal orientation of the substrate is (100); Forming a first passivation layer and a second passivation layer on two opposite surfaces of the substrate respectively; Forming a plurality of release holes in a preset position area of ​​the first passivation layer, and the release holes penetrate the first passivation layer; Wet-etching the substrate through the plurality of release holes to form an initial cavity of a preset depth at a preset cavity position of the substrate, wherein the preset cavity position corresponds to the preset position area; forming a first deposition layer on the first passivation layer to seal the initial cavity to form a sealed cavity; A device region is formed at a preset device position of the first deposition layer to form an absolute pressure sensor; wherein the preset device position corresponds to the preset cavity position in a vertical direction.

2. The method for manufacturing the absolute pressure sensor according to claim 1, characterized in that: A plurality of release holes are formed at preset positions of the first passivation layer, including: forming a patterned mask layer on the first passivation layer of the substrate, wherein the patterned mask layer comprises a plurality of release hole patterns; The first passivation layer is etched using the patterned mask layer as a mask to form a plurality of release hole patterns in a preset position area of ​​the first passivation layer.

3. The method for manufacturing the absolute pressure sensor according to claim 1, characterized in that: The plurality of release holes are evenly distributed in the preset position area.

4. The method for manufacturing the absolute pressure sensor according to claim 1, characterized in that: The first deposition layer is formed on the surface of the first passivation layer by a chemical vapor deposition process; the pressure of the chemical vapor deposition process is 0.1 Torr-1.0 Torr.

5. The method for manufacturing the absolute pressure sensor according to claim 1, characterized in that: The first deposition layer is formed on the surface of the first passivation layer by an epitaxial process; the pressure of the epitaxial process is 1e -4 Millitorr - 760 Torr.

6. The method for manufacturing the absolute pressure sensor according to any one of claims 1 to 5, characterized in that: The first deposition layer is a polysilicon layer.

7. The method for manufacturing the absolute pressure sensor according to claim 6, characterized in that: The thickness of the polysilicon layer is 1 micrometer to 50 micrometers.

8. The method for manufacturing an absolute pressure sensor according to claim 1, characterized in that: The initial cavity has an inverted terrace shape, and the preset depth is greater than 10 microns.

9. The method for manufacturing an absolute pressure sensor according to claim 1, characterized in that: The wet etching solution is an alkaline etching solution.

10. An absolute pressure sensor structure, characterized in that: The absolute pressure sensor is manufactured according to the manufacturing method of any one of claims 1 to 9, and the sensor comprises: A substrate, wherein the crystal orientation of the substrate is (100); A first passivation layer and a second passivation layer, wherein the first passivation layer and the second passivation layer are respectively formed on two opposite surfaces of the substrate; A plurality of release holes are formed in a preset position area of ​​the first passivation layer, and the release holes penetrate the first passivation layer; A sealed cavity is formed in a preset cavity position of the substrate, and the sealed cavity is in an inverted terrace shape; wherein the position of the sealed cavity corresponds to the preset position area; A first deposition layer, formed on the first passivation layer, the first deposition layer serving as a sealing layer of the sealed cavity; A device area is formed at a preset device position in the first deposition layer; the preset device position corresponds to the position of the sealed cavity in a vertical direction.

Images