Pressure sensor

Abstract

To provide a pressure sensor capable of reducing zero-point shift caused by deposition by film deposition process.SOLUTION: The pressure sensor comprises: a sensor element 9; a housing (package) 2; a support diaphragm 4 having a pressure guide opening 13; and a pedestal member 16 holding the support diaphragm 4 together with the sensor element 9. The sensor element 9 is bonded to the support diaphragm 4 with the opening 13 of the support diaphragm 4 closed. The pedestal member 16 includes a pressure guide part 18 which is bonded to the support diaphragm 4 so as to overlap the opening 13 of the support diaphragm 4. The pressure guide part 18 of the pedestal member 16 is composed of a plurality of pressure guide holes 17 with openings of the same shape. The plurality of pressure guide holes 17 is disposed on a plurality of concentric circles coaxial to the center of the support diaphragm 4, and uniformly distributed per unit area of an opening plane 4a of the support diaphragm 4.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pressure sensor having a diaphragm that comes into contact with a fluid to be measured. [Background technology]

[0002] Vacuum gauges using capacitance pressure sensors are used, for example, in semiconductor manufacturing equipment. Among the various processes performed in semiconductor manufacturing equipment, this type of vacuum gauge is used not only in the film deposition process but also in the process of etching wafers such as silicon wafers. Film deposition methods used in the film deposition process include sputtering, CVD (chemical vapor deposition), and ALD (atomic layer deposition).

[0003] In the film deposition and etching processes used in semiconductor manufacturing equipment, the films being deposited and by-products generated during the process accumulate to a greater or lesser extent inside chambers, piping, and pumps, causing various problems.Among these, the accumulation of the above-mentioned substances on the diaphragm pressure-receiving surface of the pressure sensor of the vacuum gauge, which measures and controls the gas pressure in the process, is known to cause a shift in the zero point and a change in pressure sensitivity, significantly affecting the quality of the film deposition and etching.

[0004] Diaphragm structures such as those shown in Patent Documents 1 and 2 have been proposed as attempts to suppress the effects of deposited films by structuring the pressure-receiving surface of the diaphragm of a diaphragm vacuum gauge. Patent Documents 1 and 2 describe methods for dividing the deposited film and suppressing the effects of film stress on the diaphragm by providing a table-shaped, inverted-tapered, or square-wave-shaped structure or a honeycomb-shaped beam structure on the pressure-receiving surface of the diaphragm. However, such measures are considered to be less effective for processes such as ALD, which deposit uniform films based on physical and chemical adsorption on the surface.

[0005] In order to suppress the influence of the deposited film, it is conceivable to provide the diaphragm with honeycomb-shaped irregularities, as disclosed in, for example, Patent Document 3. Patent Document 3 discloses a technology in which a diaphragm is provided with a large number of honeycomb-shaped irregularities to adjust the moment generated in the diaphragm due to the expansion and contraction of the deposited film.

[0006] Patent Document 4 discloses a technology that reduces the zero-point shift of the sensor output by directing contaminants, such as those contained in film-forming gas, to a diaphragm in a predetermined pattern, rather than suppressing the adhesion of a deposited film, while allowing the formation of a deposited film. The device described in Patent Document 4 has a baffle upstream of the pressure sensor. The baffle has multiple arc-shaped elongated holes for passing gas. These elongated holes are arranged in multiple concentric circles radially outward from the center of the diaphragm. The arc length of each arc-shaped hole increases radially outward from the center of the diaphragm. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2009-524024 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-107214 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-265041 [Patent Document 4] Patent No. 4607889 Summary of the Invention [Problem to be solved by the invention]

[0008] The method described in Patent Document 3 is extremely effective when a uniform, homogeneous film is formed uniformly on the diaphragm by forming the irregularities to ideal dimensions. However, there is a limit to how small the processing tolerances can be, and manufacturing variations can sometimes prevent sufficient processing at the center of the diaphragm, resulting in some cases where the effect of adjusting the moment is not achieved.

[0009] As a result of verifying the effects of the technology described in Patent Document 4, it was found that the effect of suppressing the zero point shift was not improved, and further improvement was found to be necessary, as will be described in detail later.

[0010] The effects of the accumulation of by-products as described above lead to a decrease in the measurement accuracy of the pressure sensor, so in order to realize a vacuum gauge with high measurement accuracy, it is necessary to make the zero point shift as small as possible, and improvements are being sought. An object of the present invention is to provide a pressure sensor in which the zero point shift caused by deposition in a film formation process is reduced. [Means for solving the problem]

[0011] The pressure sensor according to the present invention comprises a package that houses the sensor element, and a support structure that supports the sensor element within the package, the support structure having a ring-shaped support diaphragm whose outer edge is fixed to the package and has an opening in the center, and a base member that cooperates with the sensor element to sandwich the support diaphragm, the sensor element being bonded to the support diaphragm in a state where the opening of the support diaphragm is blocked, the base member having a pressure guiding portion that is bonded to the support diaphragm so as to overlap the opening of the support diaphragm, the pressure guiding portion of the base member being constituted by a plurality of pressure guiding holes of the same shape, the pressure guiding holes being arranged on a plurality of concentric circles that are coaxial with the center of the base member, and being arranged so as to be evenly distributed per unit area of ​​the opening plane of the pressure guiding portion of the base member.

[0012] In order to achieve this object, the pressure sensor of the present invention comprises a sensor element that detects pressure, a package that houses the sensor element, and a support structure that supports the sensor element within the package, wherein the support structure comprises a support diaphragm that is formed in a flat plate shape having an opening for introducing pressure and whose outer edge is fixed to the package, and a base member that cooperates with the sensor element to sandwich the support diaphragm, wherein the sensor element is joined to the support diaphragm in a state where it closes the opening of the support diaphragm, and the base member has a pressure introducing portion that is joined to the support diaphragm so as to overlap the opening of the support diaphragm, and the opening of the support diaphragm is constituted by pressure introducing holes having a plurality of openings of the same shape, and the pressure introducing holes are arranged on a plurality of concentric circles that are coaxial with the center of the support diaphragm and are arranged so as to be evenly distributed per unit area of ​​the opening plane of the pressure introducing hole of the support diaphragm.

[0013] In the pressure sensor of the present invention, the opening shape of the pressure introducing hole may be circular. In the pressure sensor of the present invention, the opening shape of the pressure introducing hole may be polygonal.

[0014] In the pressure sensor of the present invention, the sensor element has a first circular recess whose opening is blocked by the support diaphragm, a second circular recess that opens toward the opposite side of the support diaphragm, and a sensor diaphragm formed at the boundary between the first circular recess and the second circular recess, and the inner diameter of the first circular recess is larger than the inner diameter of the second circular recess, and the pressure guide hole may also be formed radially outward from the second circular recess when viewed in the thickness direction of the support diaphragm. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a pressure sensor in which the zero point shift caused by deposition in a film formation process is reduced. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view of a pressure sensor according to the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the sensor element and the support structure. [Figure 3] FIG. 3 is a perspective cross-sectional view of the sensor element and the support structure. [Figure 4] FIG. 4 is a plan view of the base member. [Figure 5] FIG. 5 is a graph showing the relationship between variations in the shape and arrangement of the pressure introducing holes and the magnitude of the zero point shift. [Figure 6] FIG. 6 is an exploded perspective view of a sensor element and a support structure according to the second embodiment. [Figure 7] FIG. 7 is a plan view of the base member. DETAILED DESCRIPTION OF THE INVENTION

[0017] (First embodiment) Hereinafter, an embodiment of a pressure sensor according to the present invention will be described in detail with reference to FIGS. The pressure sensor shown in FIG. 1 is a so-called capacitance type pressure sensor, and is configured by assembling various functional parts into a housing 2, which is the outermost package depicted in FIG. 1, a cylindrical upper housing 3, a cylindrical lower housing 5 welded to the upper housing 3 with a support diaphragm 4 sandwiched between the upper housing 3 and the lower housing 5, and a cover 6 that closes the opening of the lower housing 5. An electrode terminal 7 for transmitting signals passes through the cover 6. The electrode terminal 7 is connected to a sensor element 9 (described later) via a conductive contact spring 8.

[0018] The end of the upper housing 3 opposite to the lower housing 5 is an inlet 11 into which the fluid to be measured is introduced. The support diaphragm 4 constitutes part of a support structure 12 that supports the sensor element 9 within the housing 2. As shown in FIG. 2, the support diaphragm 4 in this embodiment is formed in a ring shape having one pressure-conducting opening 13, and its outer edge is fixed to the housing 2. As shown in FIG. 1, the support diaphragm 4 divides the interior of the housing 2 into a fluid chamber 14 that communicates with the introduction portion 11 and a vacuum chamber 15 within the lower housing 5. The fluid to be measured is introduced into the fluid chamber 14, and the interior of the vacuum chamber 15 is maintained in a vacuum state of a predetermined vacuum level.

[0019] The support structure 12 is made up of the support diaphragm 4 and a base member 16 which, together with the sensor element 9, sandwiches the outer edge of the central opening 13 of the support diaphragm 4. The sensor element 9 and base member 16 are joined so as to surround the central opening 13 of the support diaphragm 4. As shown in FIG. 3 , the base member 16 in this embodiment has a pressure guiding section 18 made up of a plurality of pressure guiding holes 17, and is joined to the surface 4a of the support diaphragm 4 facing the fluid chamber 14 so that the pressure guiding section 18 overlaps the opening 13 of the support diaphragm 4. The pressure guiding section 18 will be described later.

[0020] The sensor element 9 is joined to the surface 4b of the support diaphragm 4 on the vacuum chamber 15 side in a state where it closes the opening 13 of the support diaphragm 4. In this embodiment, the base member 16 and the sensor element 9 are formed so that their shapes match when viewed in the thickness direction of the support diaphragm 4. A base member 16 and a sensor element 9 are joined to both sides of the support diaphragm 4, respectively, so that the interior of the housing 2 is airtightly separated into a fluid chamber 14 and a vacuum chamber 15.

[0021] The sensor element 9 is configured to detect pressure based on capacitance that changes in response to the pressure difference between the pressure of the fluid to be measured and the pressure in the vacuum chamber. Specifically, as shown in Fig. 3, the sensor element 9 includes a sensor diaphragm 25 that bends toward the vacuum chamber 15 in response to the pressure difference between the pressure of the fluid to be measured acting on the pressure-receiving surface on the fluid chamber 14 side and the pressure acting on the pressure-receiving surface on the vacuum chamber 15 side, a sensor diaphragm support portion 21 that forms the outer edge of the sensor diaphragm 25 and has one end face joined to the surface 4b of the support diaphragm 4 on the vacuum chamber 15 side, and a sensor base 22 that is joined to the other end face of the sensor diaphragm support portion 21. The sensor diaphragm support portion 21 and the sensor base 22 are formed of, for example, sapphire.

[0022] A first circular recess 23 is formed by the pressure-receiving surface of the sensor diaphragm 25 on the fluid chamber 14 side and the inner wall of the sensor diaphragm support part 21 on the fluid chamber 14 side, while a second circular recess 24 is formed by the pressure-receiving surface of the sensor diaphragm 25 on the vacuum chamber 15 side and the inner wall of the sensor diaphragm support part 21 on the vacuum chamber 15 side. The centers of the first circular recess 23 and the second circular recess 24 are positioned on the same axis as the center of the support diaphragm 4. The opening of the first circular recess 23 is closed by the base member 16. The opening of the second circular recess 24 is closed by the sensor base 22. The inner diameter D1 of the first circular recess 23 is larger than the inner diameter D2 of the second circular recess 24. In this embodiment, the inner diameter D1 of the first circular recess 23 and the inner diameter D3 (see FIG. 2) of the opening of the support diaphragm 4 are approximately equal.

[0023] The thin disk-shaped portion that forms the boundary between the first circular recess 23 and the second circular recess 24 serves as the sensor diaphragm 25. The size of the movable part of sensor diaphragm 25 according to this embodiment is determined by the inner diameter of second circular recess 24. That is, the circular bottom surface of first circular recess 23, which is on the outer circumferential side of the inner diameter of second circular recess 24, does not function as sensor diaphragm 25.

[0024] By joining one end face of the sensor diaphragm support portion 21 to the support diaphragm 4, the space surrounded by the sensor diaphragm 25, the inner wall of the sensor diaphragm support portion 21 on the fluid chamber 14 side, and the base member 16 is formed as a pressure introducing chamber 26. Meanwhile, by joining the sensor pedestal 22 to the other end surface of the sensor diaphragm support portion 21, a space surrounded by the sensor diaphragm 25, the inner wall of the sensor diaphragm support portion 21 on the vacuum chamber 15 side, and the sensor pedestal 22 is formed as a reference vacuum chamber 27. This reference vacuum chamber 27 is in communication with the vacuum chamber 15 via a through-hole (not shown) that penetrates the sensor pedestal 22.

[0025] Electrodes 28, 29 for measuring capacitance are provided on the opposing surfaces of the sensor diaphragm 25 and the sensor base 22. These electrodes 28, 29 work together as a capacitor and are electrically connected to the above-mentioned contact spring 8 via conductors (not shown). Therefore, data on the capacitance of the capacitor formed by the electrodes 28, 29 detected by the sensor element 9 is sent from the sensor element 9 to a measurement circuit (not shown) via conductors (not shown), the contact spring 8, and the electrode terminal 7 of the cover 6.

[0026] Base member 16 is formed into a plate shape from, for example, sapphire. As shown in Fig. 3, a plurality of pressure introducing holes 17 constituting pressure introducing portion 18 of base member 16 are formed so as to penetrate base member 16 in the thickness direction. The opening shape of all pressure introducing holes 17 is the same circular shape, and all pressure introducing holes 17 have the same hole diameter. 4, the plurality of pressure guiding holes 17 formed in the pressure guiding portion 18 of the base member 16 are formed based on the following predetermined rule: The rule for forming the pressure guiding holes 17 is to arrange the plurality of pressure guiding holes 17, each having an opening of the same shape, on multiple concentric circles that are coaxial with the center C of the base member 16, and to arrange the pressure guiding holes 17 so that they are evenly distributed per unit area of ​​the opening plane 16a of the pressure guiding portion 18 of the base member 16.

[0027] The "plurality of concentric circles coaxial with the center C of the base member 16" referred to here refers to a plurality of imaginary circles 31 to 36 of different diameters that are positioned coaxially with the center C of the base member 16, as indicated by the two-dot chain line in Fig. 4. Furthermore, the "opening plane 16a of the pressure guiding portion 18 of the base member 16" refers to the surface 16a of the base member 16 on which the openings of the pressure guiding holes 17 provided in the pressure guiding portion 18 are formed. Furthermore, the phrase "evenly distributed per unit area" means that when the opening plane 16a is partitioned by a frame that surrounds a space of a predetermined unit area, the number of pressure guiding holes 17 within each frame is the same in all frames.

[0028] Furthermore, the outer edge of the range of the pressure guiding portion 18 in which the plurality of pressure guiding holes 17 are formed is near the inside of the opening 13 of the support diaphragm 4 when viewed from a direction perpendicular to the opening plane 16a (the thickness direction of the support diaphragm 4). In FIG. 4, the position of the opening 13 of the support diaphragm 4 is indicated by a dashed line L1, and the position of the outer circumferential surface of the second circular recess 24 of the sensor element 9 is indicated by a dashed line L2. As shown in FIG. 4, the plurality of pressure guiding holes 17 are also formed radially outward of the second circular recess 24 when viewed from the thickness direction of the base member 16. The size of the movable part of sensor diaphragm 25 is determined by the inner diameter of second circular recess 24. That is, of the circular bottom surface of first circular recess 23, a part on the outer periphery side (a part radially outward from second circular recess 24) does not function as sensor diaphragm 25.

[0029] In the capacitance type pressure sensor 1 configured as described above, the fluid to be measured introduced into the housing 2 from the introduction portion 11 of the housing 2 flows into the pressure introduction chamber 26 of the sensor element 9 through the multiple pressure introducing holes 17 of the base member 16 and the opening 13 of the support diaphragm 4. The sensor diaphragm 25 is displaced so as to bend toward the reference vacuum chamber 27 in accordance with the magnitude of the pressure difference between the pressure of the fluid to be measured in the pressure introduction chamber 26 and the pressure (vacuum) in the reference vacuum chamber 27. The pressure sensor 1 measures the pressure of the fluid to be measured based on the amount of displacement of the sensor diaphragm 25.

[0030] If the fluid to be measured contains a film-forming substance, the film-forming substance will flow into the pressure introducing chamber 26 along with the fluid to be measured and come into contact with the circular bottom surface of the first circular recess 23, i.e., the pressure-receiving surface of the sensor diaphragm 25, and eventually deposit on this pressure-receiving surface to form a film. The more extensive the film formed on the pressure-receiving surface of the sensor diaphragm 25 and the thicker the film, the more stress it will impart to the sensor diaphragm 25, causing deflection (zero point shift) of the sensor diaphragm 25 that is unrelated to the pressure of the fluid to be measured, and ultimately degrading the measurement accuracy of the pressure sensor 1. Therefore, to mitigate the adverse effects of a zero point shift on the pressure sensor 1 due to the deposition of the film-forming substance on the pressure-receiving surface of the sensor diaphragm 25, it is important to limit the film-forming area so that it does not spread too far and to ensure that the film-forming area on the pressure-receiving surface of the sensor diaphragm 25 is not displaced. In addition, the film formation status and film formation position of the film-forming substance on the pressure-receiving surface of the sensor diaphragm 25 depend on the position and shape of the opening of the pressure-guiding hole 17 formed in the base member 16, which is the end of the inflow path of the measured fluid into the pressure-introducing chamber 26.

[0031] Therefore, focusing on the above points, we have searched for the position and shape of the opening of the pressure-guiding hole 17 formed in the base member 16 that can effectively mitigate the effect of the zero-point shift on the pressure sensor 1, and as a result, we have come up with the first embodiment shown in Figures 1 to 4. According to this embodiment, the film-forming substance mixed in the fluid to be measured is dispersed among the multiple pressure introducing holes 17 formed in the base member 16 and flows into the pressure introducing chamber 26, but this dispersed film-forming substance accumulates and forms a film within an area defined by a vertical projection of the openings of each pressure introducing hole 17 on the pressure-receiving surface of the sensor diaphragm 25. That is, films each approximately the same size as the opening area of ​​a number of pressure introducing holes 17 are formed on the pressure-receiving surface of the sensor diaphragm 25 in a dispersed manner and isolated from one another (films are formed on the pressure-receiving surface of the sensor diaphragm 25 in the arrangement pattern of the pressure introducing holes 17 in the pressure-receiving surface of the sensor diaphragm 25 shown in FIG. 4). Therefore, the individual film formation areas are narrow, and adjacent films are isolated from each other so that adjacent films do not join together to form larger films. Furthermore, each film is uniformly distributed on the surface of the sensor diaphragm 25, so that the sensor diaphragm 25 is not affected by the films, or even if there is an effect, the effect of the films is negligible. As a result, the zero point shift is reduced. Therefore, according to this embodiment, it is possible to provide a pressure sensor in which the zero point shift caused by deposition in the film formation process is reduced.

[0032] When a simulation was carried out to examine the relationship between variations in the shape and arrangement of the pressure introducing holes 17 formed in the base member 16 and the zero point shift, the results shown in FIG. 5 were obtained. The upper part of Figure 5 shows a graph illustrating the relationship between eight types of pressure guide hole 17 shapes and zero point shift, and the lower part shows a schematic diagram illustrating four representative types of pressure guide hole 17 shapes.

[0033] Of the four types of configurations of the pressure introducing holes 17, it was found that when the configuration shown on the left side of the graph in Fig. 5, designated by reference numeral 1, in which the pressure introducing holes 17 are sparsely formed toward the center of the base member 16 and densely formed toward the outer periphery, is adopted, a large zero point shift occurs in the negative range. This configuration of the pressure introducing holes 17 is similar to the structure described in Patent Document 4, in which multiple arc-shaped elongated holes are provided. For this reason, when the structure described in Patent Document 4 is adopted, a large zero point shift occurs.

[0034] Of the four types of pressure introducing holes 17, if the number of pressure introducing holes 17 formed toward the center of the base member 16 is increased and the number of pressure introducing holes 17 formed toward the outer periphery of the base member 16 is reduced compared to the configuration depicted on the left side, the zero point shift gradually decreases in the negative range, as indicated by reference numeral 2 in the graph of Fig. 5. Furthermore, if the configuration in which the pressure introducing holes 17 are evenly formed in the base member 16, as indicated by reference numeral 3 in the graph of Fig. 5 (the embodiment shown in Figs. 1 to 4), is adopted, the zero point shift occurs only slightly in the positive range. This level of zero point shift is negligible.

[0035] It was found that by further increasing the number of pressure guiding holes 17 formed on the center side of the base member 16 and further reducing the number of pressure guiding holes 17 formed on the outer periphery of the base member 16 so that the pressure guiding holes 17 are denser on the center side of the base member 16 and sparser on the outer periphery side, the zero point shift becomes even larger in the positive region, as shown by symbols 4 to 7 in the graph of FIG. 5. As shown by reference numeral 8 in the graph of FIG. 5, when the base member 16 has four pressure introducing holes 17 formed therein, it was found that a zero point shift occurs in the negative region to an extent that cannot be ignored. In this way, by forming the pressure introducing holes 17 uniformly in the base member 16, the zero point shift can be reduced to a negligible level.

[0036] (Second embodiment) Instead of providing the pressure introducing holes in the base member 16 as shown in the first embodiment, they may be provided in the support diaphragm as shown in Fig. 6. In Fig. 6, the same or equivalent members as those described in Figs. 1 to 5 are designated by the same reference numerals, and detailed description thereof will be omitted where appropriate.

[0037] The support diaphragm 4 shown in Fig. 6 is formed in a disk shape and has, in its center, an opening 13 consisting of a plurality of pressure guiding holes 17. The base member 16 shown in Fig. 6 is formed in a ring shape and has, in its center, a pressure guiding part 18 consisting of a single hole. The plurality of pressure introducing holes 17 provided in the support diaphragm 4 are formed so as to penetrate the support diaphragm 4 in the thickness direction. The opening shape of all of the pressure introducing holes 17 is the same circular shape, and all of the pressure introducing holes 17 have the same hole diameter. These pressure introducing holes 17 are formed based on the same rules as when the first embodiment is adopted. That is, the pressure introducing holes 17 are arranged on multiple concentric circles that are coaxial with the center of the support diaphragm 4, and the pressure introducing holes 17 are arranged so that they are evenly distributed per unit area of ​​the pressure introducing hole opening plane 4a of the support diaphragm 4 (the surface on the fluid chamber 14 side).

[0038] The plurality of pressure introducing holes 17 provided in the support diaphragm 4 are formed in a circular range when viewed in the thickness direction of the support diaphragm 4. The outer edge of this circular range overlaps with the outer edge of the first circular recess 23 formed in the sensor element 9 when viewed in the thickness direction of the support diaphragm 4. In other words, the plurality of pressure introducing holes 17 in the support diaphragm 4 are also formed radially outward of the second circular recess 24 of the sensor element 9 when viewed in the thickness direction of the support diaphragm 4. Also in the second embodiment, similarly to the first embodiment, the inner diameter of the first circular recess 23 of the sensor element 9 is larger than the inner diameter of the second circular recess 24. The pressure introducing hole 17 is also formed radially outward of the second circular recess 24 when viewed in the thickness direction of the support diaphragm 4 (thickness direction of the base member 16).

[0039] Therefore, even when this embodiment is adopted, if the fluid to be measured contains a film-forming substance, the film-forming substance mixed in the fluid to be measured will disperse into the multiple pressure-conducting holes 17 formed in the support diaphragm 4 and flow into the pressure-introducing chamber 26, but this dispersed film-forming substance will accumulate almost entirely within the range defined by the vertical projection of the openings of each pressure-conducting hole 17 on the pressure-receiving surface of the sensor diaphragm 25, forming a film there. That is, films each having a size roughly equivalent to the opening area of ​​a single pressure lead hole 17 are formed on the pressure-receiving surface of sensor diaphragm 25 in a dispersed, spaced relationship (the films are formed on the pressure-receiving surface of sensor diaphragm 25 in the arrangement pattern of pressure lead holes 17 of pressure guiding section 18 shown in FIG. 4), so the individual film formation areas are narrow and adjacent films are isolated from each other, so adjacent films do not join together to form larger films, and the films on the surface of sensor diaphragm 25 are evenly distributed, so that sensor diaphragm 25 is not affected by the films, or any effect of the films is negligible. As a result, the zero point shift is reduced. Therefore, according to this embodiment, it is possible to provide a pressure sensor in which the zero point shift caused by deposition in the film formation process is reduced.

[0040] In the first and second embodiments described above, the pressure guiding hole 17 has been described as having a circular opening, but the shape of the pressure guiding hole 17 is not limited to this, and a shape having a polygonal opening, such as a hexagonal opening as shown in FIG. 7, can also be used. [Explanation of symbols]

[0041] 1...pressure sensor, 2...housing (package), 4...support diaphragm, 9...sensor element, 12...support structure, 13...opening, 16...base member, 17...pressure guiding hole, 18...pressure guiding portion, 23...first circular recess, 24...second circular recess, 25...sensor diaphragm

Claims

1. a sensor element for detecting pressure; a package that houses the sensor element; a support structure that supports the sensor element within the package, The support structure includes: a ring-shaped support diaphragm having an outer edge fixed to the package and an opening at its center; a base member that cooperates with the sensor element to sandwich the support diaphragm therebetween, the sensor element is bonded to the support diaphragm in a state where the sensor element closes an opening of the support diaphragm; the base member has a pressure guiding portion, and the pressure guiding portion is joined to the support diaphragm so as to overlap with the opening of the support diaphragm; the pressure guiding portion of the base member is configured by a plurality of pressure guiding holes of the same shape, The pressure sensor is characterized in that the pressure guide holes are arranged on a plurality of concentric circles that are coaxial with the center of the base member, and are arranged so as to be evenly distributed per unit area of ​​the opening plane of the pressure guide portion of the base member.

2. a sensor element for detecting pressure; a package that houses the sensor element; a support structure that supports the sensor element within the package, The support structure includes: a support diaphragm formed in a flat plate shape having a pressure-conducting opening and having an outer edge portion fixed to the package; a base member that cooperates with the sensor element to sandwich the support diaphragm therebetween, the sensor element is bonded to the support diaphragm in a state where the sensor element closes the opening of the support diaphragm; the base member has a pressure guiding portion, and the pressure guiding portion is joined to the support diaphragm so as to overlap with the opening of the support diaphragm; the opening of the support diaphragm is configured by a pressure guide hole having a plurality of openings of the same shape, The pressure sensor is characterized in that the pressure guide holes are arranged on a plurality of concentric circles that are coaxial with the center of the support diaphragm, and are arranged so as to be evenly distributed per unit area of ​​the pressure guide hole opening plane of the support diaphragm.

3. 3. The pressure sensor according to claim 1, A pressure sensor characterized in that the opening shape of the pressure introducing hole is circular.

4. 3. The pressure sensor according to claim 1, A pressure sensor characterized in that the opening shape of the pressure introducing hole is polygonal.

5. 3. The pressure sensor according to claim 1, The sensor element is a first circular recess whose opening is closed by the support diaphragm; a second circular recess that opens toward a side opposite to the support diaphragm; a sensor diaphragm formed at a boundary between the first circular recess and the second circular recess, an inner diameter of the first circular recess is larger than an inner diameter of the second circular recess; The pressure sensor is characterized in that the pressure introducing hole is also formed radially outward of the second circular recess when viewed in the thickness direction of the support diaphragm.

Images