Metal components with insulating films and physical quantity sensors

Abstract

To provide a metal film with an insulation film which can prevent occurrence of cracking or peeling in an edge part of an insulation film.SOLUTION: The metal film with an insulation film includes: a metal member having a film formation surface and a connection surface facing a direction different from the direction which the film formation surface faces and connecting to the film formation surface; an insulation film covering a part of the film formation surface and the connection surface across the connection position of the film formation surface and the connection surface; and a reinforcing part formed along an end part of the insulation film which covers the connection position of the insulation film, the reinforcing part covering at least a part of the edge part of the insulation film from the opposite side from the side where the metal member is formed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0005] ,

[0001] The present invention relates to a metal member with an insulating film, a physical quantity sensor having the same, and a pressure sensor.

Background Art

[0002] In pressure sensors and physical quantity sensors, a metal member with an insulating film formed on a metallic metal member may be used. In a metal member with an insulating film, while utilizing excellent characteristics such as mechanical characteristics such as the elasticity of the metal member and durability at high temperatures, by forming an insulating film, electrical elements such as a detection circuit using a strain resistance film or the like can be added to the conductive metal member in an insulated form.

[0003] However, since the insulating film has mechanical characteristics such as a linear expansion coefficient and Young's modulus that are significantly different from those of the metal member, and its mechanical strength tends to be inferior to that of the metal member, there is a problem that peeling and damage are likely to occur. In addition, since the insulating film tends to peel off from the outer edge, it is also conceivable to form the insulating film widely on the metal member so as to cover not only the film formation surface for forming a detection circuit or the like but also the connection surface such as the side surface connected to the film formation surface.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the insulating film edge portion where the surface of the insulating film changes its orientation along the orientation of the surface of the metal member, damage such as cracks tends to occur. Therefore, cracks and peeling from the insulating film edge portion to the insulating film on the film formation surface may progress, and the insulating film may deteriorate in performance with respect to insulation or shielding properties of liquids, gases, etc.

[0006] This disclosure provides a metal component with an insulating film that can prevent cracks and delamination at the edges of the insulating film. [Means for solving the problem]

[0007] The insulating metal member relating to this disclosure is A metal member having a film-forming surface and a connecting surface that faces a different direction from the film-forming surface and connects to the film-forming surface, An insulating film covering at least a portion of the film-forming surface and the connecting surface, spanning the connection position between the film-forming surface and the connecting surface, The insulating film has a reinforcing portion formed along the insulating film edge, which is the portion that covers the connection position, and covers at least a part of the insulating film edge from the side opposite to the metal member.

[0008] Such metal components with insulating films have reinforcing portions formed along the edges of the insulating film, which effectively prevents cracks and delamination at the edges of the insulating film and prevents a deterioration in the performance of the insulating film.

[0009] Furthermore, for example, the reinforcing portion may be made of a thin metal film.

[0010] The metal thin film possesses moderate strength and conformability to the insulating film, making it suitable as a reinforcement for the edges of the insulating film.

[0011] Furthermore, for example, the metal thin film may have an Au layer containing Au.

[0012] The Au layer has good ductility and is less prone to cracking, making it suitable as a reinforcement for the edges of the insulating film. Furthermore, the Au layer is chemically stable, has excellent weather resistance, and tends to have low stress levels, making it less susceptible to delamination due to stress.

[0013] Furthermore, for example, the metal thin film may have a Pt layer containing Pt.

[0014] The Pt layer exhibits excellent thermal stability, making it particularly suitable as a reinforcement layer for the edges of insulating films, especially in high-temperature environments.

[0015] Furthermore, for example, the metal thin film may have multiple layers. The metal thin film may have an adhesion layer that is in contact with the insulating film and has higher adhesion to the insulating film than other layers.

[0016] Because a metal thin film having such an adhesive layer has high adhesion to the insulating film, it can effectively reinforce the edges of the insulating film and effectively prevent cracks and delamination from occurring at the insulating edges.

[0017] Furthermore, the physical quantity sensor relating to the first aspect of this disclosure comprises the aforementioned insulating film-coated metal member, A detection unit is formed on the upper side of the film-forming surface and on the opposite side of the film-forming surface, with the insulating film in between, to detect a physical quantity relating to the metal member, The electrode film is formed so as to overlap a part of the detection unit from above, and a wiring portion is connected to the detection unit to ensure electrical conductivity to the outside of the detection unit. The metal thin film of the reinforcing portion includes a layer common to at least a portion of the layers included in the electrode film.

[0018] Physical quantity sensors having such reinforced sections prevent degradation of the insulating film performance and have good durability. Furthermore, since at least a portion of the reinforced section can be formed simultaneously during the layer formation process included in the electrode film, such physical quantity sensors offer excellent productivity.

[0019] Furthermore, the physical quantity sensor relating to the second aspect of this disclosure comprises the aforementioned insulating film-coated metal member, It has a detection unit that is formed on the upper side of the film-forming surface and on the opposite side of the film-forming surface, with the insulating film in between, for detecting a physical quantity relating to the metal member, The metal member has a stem shape comprising a membrane having the film-forming surface and a side wall portion having the connecting surface. The detection unit detects the amount of deformation of the membrane.

[0020] A physical quantity sensor having such a reinforcing portion preferably prevents damage and performance degradation of an insulating film formed on a stem-shaped metal member and has good durability.

[0021] In addition, the pressure sensor according to the present disclosure includes the above-described metal member with an insulating film, and a detection unit that is formed on the upper side of the film formation surface and on the opposite side of the film formation surface across the insulating film and detects a physical quantity related to the metal member. The metal member has a stem shape having a membrane having the film formation surface and a side wall portion having the connection surface. The detection unit detects a deformation amount of the membrane due to pressure.

[0022] A pressure sensor having such a reinforcing portion preferably prevents damage and performance degradation of an insulating film formed on a stem-shaped metal member and has good durability. Further, such a pressure sensor can be particularly preferably used as a pressure sensor under high temperature and high pressure because the insulating film has good durability.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a schematic cross-sectional view of a metal member with an insulating film according to the first embodiment. [Figure 2] FIG. 2 is a top view of the metal member with an insulating film shown in FIG. 1 and a metal member with an insulating film according to a modified example. [Figure 3] FIG. 3 is a schematic cross-sectional view of a metal member with an insulating film according to the second embodiment. [[ID=3,3]] [Figure 4] FIG. 4 is a schematic cross-sectional view of a metal member with an insulating film according to the third embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view of a pressure sensor according to the fourth embodiment. [Figure 6] FIG. 6 is a top view of the metal member with an insulating film included in the pressure sensor shown in FIG. 5. [Figure 7]Figure 7 is a schematic cross-sectional view showing the insulating metal component and its surrounding area in the pressure sensor shown in Figure 5. [Modes for carrying out the invention]

[0024] The present invention will be described below based on the embodiments shown in the drawings.

[0025] First Embodiment Figure 1 is a schematic cross-sectional view of the insulating film-coated metal member 10 according to the first embodiment, and Figure 2 is a top view of the insulating film-coated metal member 10 as seen from above. In each figure, for the purpose of explaining the various parts included in the insulating film-coated metal member 10, the dimensions of each part are shown in proportions different from those of the actual parts.

[0026] As shown in Figure 1, the insulating film-coated metal member 10 comprises a metal member 20, an insulating film 50, and a reinforcing portion 60. The metal member 20 shown in Figure 1 has a substantially cylindrical shape, but the shape of the metal member 20 used in the insulating film-coated metal member 10 is not limited to a cylindrical shape, and may be a rectangular parallelepiped or other polygonal prism, cylinder, or polygonal polyhedron.

[0027] The material of the metal component 20 can be any single metal or alloy, such as steel, aluminum alloy, stainless steel, or nickel alloy. Furthermore, it is preferable to use one material selected from austenitic stainless steels such as SUS304 and SUS316, or precipitation-type austenites such as SUS630 and SUS631, for the material of the metal component 20 from the viewpoint of improving the durability of the insulating film-coated metal component 10 in high-temperature environments.

[0028] As shown in Figure 1, the metal member 20 has a film-forming surface 22b and a connecting surface 24a. The film-forming surface 22b of the metal member 20 is one of the bottom surfaces of the cylinder, and the connecting surface 24a is a side surface of the cylinder. However, the shapes of the film-forming surface 22b and the connecting surface 24a are not limited to those shown in Figure 1, and any surface (film-forming surface) and any other surface (connecting surface) that faces a different direction from that surface and connects to it can be designated as the film-forming surface 22b and the connecting surface 24a.

[0029] The film-forming surface 22b is entirely covered by the insulating film 50. The film-forming surface 22b is directly covered by the insulating film 50, and the film-forming surface 22b is in contact with the lower surface of the insulating film 50. However, a portion of the film-forming surface 22b (for example, 20% or less of the total area) may be exposed from the insulating film 50. Also, although the film-forming surface 22b shown in Figure 1 is flat, the film-forming surface 22b may be curved.

[0030] As shown in Figure 1, the film-forming surface 22b faces upward, while the connecting surface 24a faces sideways (horizontally), meaning the connecting surface 24a faces a different direction from the film-forming surface 22b. The connecting surface 24a is connected to the film-forming surface 22b, and the orientation of the surface of the metal member 20 changes at the connection position 25 where the connecting surface 24a connects to the film-forming surface 22b. The orientation of the film-forming surface 22b and the connecting surface 24a is determined, for example, by the normal direction of each surface. The film-forming surface 22b and the connecting surface 24a face approximately 90 degrees apart, but the relationship between the film-forming surface 22b and the connecting surface 24a is not limited to the case where they face 90 degrees apart.

[0031] At least a portion of the connection surface 24a is covered with the insulating film 50. Since the connection surface 24a is the surface that connects to the film-forming surface 22b, the portion of the connection surface 24a that is particularly close to the connection position 25 is directly covered with the insulating film 50 that is continuous with the film-forming surface 22b. The connection surface 24a also comes into contact with the insulating film 50, similar to the film-forming surface 22b.

[0032] However, the connection surface 24a may be covered entirely or mostly by the insulating film 50, similar to the film-forming surface 22b, but unlike the film-forming surface 22b, only a portion (around the connection position 25) may be covered by the insulating film 50, with the remainder exposed from the insulating film 50. Furthermore, the boundary between the portion of the connection surface 24a covered by the insulating film 50 and the portion exposed from the insulating film 50 may be a transitional boundary due to the decrease in the thickness of the insulating film 50.

[0033] As shown in Figure 1, the insulating film 50 covers at least a portion of the film-forming surface 22b and the connecting surface 24a, spanning the connection position 25 between the film-forming surface 22b and the connecting surface 24a. The insulating film 50 is composed of, for example, silicon oxide such as SiO2, silicon nitride such as Si3N4, silicon oxynitride such as SiON, or other ceramics such as AlO3, but the material is not limited as long as it is an insulating film.

[0034] The insulating film 50 is formed on the film-forming surface 22b and connecting surface 24a of the metal member 20 by thin-film formation methods such as CVD, sputtering, or vapor deposition, but the method of forming the insulating film 50 is not particularly limited. The thickness of the insulating film 50 can be about 0.1 to 10 μm on the film-forming surface 22b, and is preferably 1 to 5 μm.

[0035] As shown in Figure 1, since the insulating film 50 is formed across the connection position 25 between the film-forming surface 22b and the connection surface 24a, an insulating film edge 57 is formed in the portion of the insulating film 50 that covers the connection position 25. In the insulating film edge 57, which is the portion of the insulating film 50 that covers the connection position 25, the direction of extension of the insulating film 50 changes in accordance with the change in the surface direction of the connection position 25 in the metal member 20, and the insulating film 50 forms an edge.

[0036] As shown in Figure 2(a), the insulating film edge 57 is formed corresponding to the outer edge of the film-forming surface 22b, i.e., the connection position 25. The insulating film edge 57 in the insulating film-coated metal member 10 has a circular shape. As shown in Figure 1, in the insulating film 50, the portion inside the insulating film edge 57 covers the film-forming surface 22b of the metal member 20, and this portion is the first insulating film portion 54. In the first insulating film portion 54, it is preferable that the thickness of the insulating film 50 is substantially constant from the viewpoint of ensuring the function of the insulating film 50 on the film-forming surface 22b.

[0037] Furthermore, in the insulating film 50, the portion outside the insulating film edge 57 covers the connection surface 24a of the metal member 20, and this portion is the second insulating film portion 56. The thickness of the second insulating film portion 56 may be the same as the thickness of the first insulating film portion 54, or it may be thinner than the first insulating film portion 54.

[0038] As shown in Figure 1, the reinforcing portion 60 covers at least a portion of the insulating film edge 57 from the side opposite to the metal member 20. That is, the reinforcing portion 60 is formed on the insulating film edge 57 and the insulating film 50 around it, and directly covers the insulating film edge 57.

[0039] As shown in Figure 2(a), the reinforcing portion 60 is formed in a ring shape along the insulating film edge 57. The reinforcing portion 60 is formed continuously along the insulating film edge 57, but does not cover the entire insulating film edge 57, and has a discontinuous portion 60a where a part of the insulating film edge 57 is exposed.

[0040] In other words, as shown in Figure 2(a), the reinforcing portion 60 of the insulating metal member 10 has a substantially C-ring shape with a non-continuous discontinuous portion 60a. However, the shape of the reinforcing portion 60 is not limited to the shape shown in Figure 2(a).

[0041] Figure 2(b) is a top view showing a metal member 110 with an insulating film according to the first modified example. As shown in Figure 2(b), the reinforcing portion 160 of the metal member 110 with an insulating film has a ring-shaped form that is continuous along the insulating film edge 57 so as to cover the entire insulating film edge 57. In addition to the shapes shown in Figures 2(a) and 2(b), other shapes of the reinforcing portion include those that are formed intermittently along the insulating film edge 57 and have multiple breaks.

[0042] The reinforcing portion 60 shown in Figures 1 and 2 is composed of a film formed on the insulating film 50, and is preferably composed of a metal thin film from the viewpoint of the ductility and strength required for the reinforcing portion 60. Examples of metals that make up the metal thin film include Au, Al, Ru, Rh, Pd, Os, Ir, Pt, Cr, Ti, Ni, and Mo, but is not particularly limited. Furthermore, the reinforcing portion 60 composed of a metal thin film may consist of a single layer as shown in Figure 1, or it may have multiple layers as in the second to fourth embodiments described later. Examples of films other than metal thin films that make up the reinforcing portion 60 include insulating films such as silicon oxide.

[0043] The metal thin film constituting the reinforcing portion 60 is formed on the insulating film 50 by a thin-film formation method such as sputtering or vapor deposition. The shape of the metal thin film constituting the reinforcing portion 60 can be formed into any shape along the edge 57 of the insulating film using photolithography or a metal mask.

[0044] The thickness of the reinforcing portion 60 shown in Figure 1 is preferably about 50 to 500 nm, and more preferably 100 to 200 nm, especially when the reinforcing portion 60 is made of a thin metal film. If the thickness of the reinforcing portion 60 is thinner than the predetermined value, it becomes difficult for the reinforcing portion 60 to form a continuous film, and the protective function of the reinforcing portion 60 on the edge of the insulating film 57 is reduced. On the other hand, if the thickness of the reinforcing portion 60 is thicker than the predetermined value, disadvantages such as a decrease in throughput due to an increase in film deposition time and an increase in raw material costs occur.

[0045] As shown in Figure 2(a), the reinforcing portion 60 may have a break 60a that exposes a part of the insulating film edge 57, but it is preferable that the reinforcing portion 60 covers 80% or more of the insulating film edge 57 from the viewpoint of preventing damage to the insulating film 50 originating from the insulating film edge 57.

[0046] As shown in Figure 2(a), the reinforcing portion 60 is formed in a strip shape along the insulating film edge 57, and as shown in Figure 1, the reinforcing portion 60 has a predetermined width from the insulating film edge 57 to the insulating film first portion 54 side and from the insulating film edge 57 to the insulating film second portion 56 side.

[0047] As shown in Figure 1, in the reinforcing portion 60, the first width W1, which is the width from the insulating film edge 57 to the end on the insulating film first portion 54 side, is preferably 50 to 350 μm, and more preferably 100 to 250 μm. By setting the first width W1 to a predetermined value or more, the insulating film edge 57 can be reliably covered and protected. Also, by setting the first width W1 to a predetermined value or less, a wide area exposed from the reinforcing portion 60 can be secured in the central part of the insulating film first portion 54. This makes it possible to secure an area on the insulating film first portion 54 for arranging other structures such as the detection unit 430 (see Figure 6), which will be described later, using a metal member 20 of a limited size.

[0048] Furthermore, in the reinforcing portion 60, the second width W2, which is the width from the insulating film edge 57 to the end of the insulating film second portion, is preferably 50 μm or more. By setting the second width W2 to a predetermined value or more, the insulating film edge 57 can be reliably covered and protected. Note that the portion of the reinforcing portion 60 from the insulating film edge 57 to the insulating film second portion 56 may have a different thickness from the portion from the insulating film edge 57 to the end of the insulating film first portion 54. For example, the portion of the reinforcing portion 60 from the insulating film edge 57 to the insulating film second portion 56 can be 10 to 110% of the maximum thickness of the portion from the insulating film edge 57 to the end of the insulating film first portion 54, and is preferably 70 to 100%.

[0049] The insulating film-coated metal member 10 having the insulating film 50 and reinforcing portion 60 as described above can reliably protect the film-forming surface 22b with the insulating film 50, and effectively prevent cracks and delamination from occurring in the first portion 54 of the insulating film on the film-forming surface 22b. Since the insulating film 50 continuously covers from the film-forming surface 22b to the connecting surface 24a, even if cracks or delamination occur at the outer edge of the insulating film 50, it is possible to prevent those cracks or delamination from propagating onto the film-forming surface 22b.

[0050] Furthermore, if the film-forming surface 22b to the connection surface 24a were simply covered with an insulating film, there is a tendency for cracks and delamination to occur at the insulating film edge 57 covering the connection position 25 between the film-forming surface 22b and the connection surface 24a. However, since the insulating film-coated metal member 10 has a reinforcing portion 60 formed along the insulating film edge 57 covering the connection position 25, the reinforcing portion 60 reinforces the insulating film edge 57, effectively preventing the problem of cracks and delamination occurring at the insulating film edge 57.

[0051] Second Embodiment Figure 3 is a schematic cross-sectional view of the insulating film-coated metal member 210 according to the second embodiment. The insulating film-coated metal member 210 is the same as the insulating film-coated metal member 10 shown in Figures 1 and 2, except that the reinforcing portion 260 is composed of a metal thin film having multiple layers. The insulating film-coated metal member 210 will be described focusing on the differences from the insulating film-coated metal member 10, and commonalities with the insulating film-coated metal member 10 will be denoted by the same reference numerals and their descriptions will be omitted.

[0052] As shown in Figure 3, the reinforcing portion 260 of the insulating film-coated metal member 210 is composed of a thin metal film formed along the insulating film edge 57, similar to the reinforcing portion 60 shown in Figure 1. The thin metal film constituting the reinforcing portion 260 has multiple layers that differ from each other in terms of their constituent elements or the composition ratio of their constituent elements.

[0053] As shown in Figure 3, the reinforcing portion 260 has an Au layer 262 containing Au and a Pt layer 264 containing Pt. The Au layer 262 constitutes the upper part of the reinforcing portion 260, and the Pt layer 264 constitutes the lower part of the reinforcing portion 260.

[0054] The Au layer 262, which contains Au, may contain elements other than Au, but at least considering the weight ratio of the elements contained in the Au layer 262, the proportion of Au is the largest. Because the Au layer 262 has high ductility, it is less prone to cracking, and can effectively prevent delamination and cracking at the insulating film edge 57 below the reinforcement part 60. In addition, because the Au layer 262 has good weather resistance, making the upper part of the reinforcement part an Au layer 262 suppresses the aging of the reinforcement part 60 and contributes to improving the durability of the film-coated metal part member 210. Furthermore, because the Au layer 262 has low stress, it is less prone to delamination due to stress with respect to the film and layer (Pt layer 264 in the case of the reinforcement part 260) in contact with the Au layer.

[0055] The Au layer 262 can be formed on the Pt layer 264 by thin-film formation methods such as sputtering or vapor deposition. The thickness of the Au layer 262 can be, for example, 50 to 500 nm, preferably 100 to 250 nm. If the thickness of the Au layer 262 is thinner than the predetermined value, it becomes difficult for the Au layer 262 to form a continuous film, and the function of the Au layer 262 deteriorates. On the other hand, if the thickness of the Au layer 262 is thicker than the predetermined value, disadvantages such as a decrease in throughput due to an increase in film formation time and an increase in raw material costs occur.

[0056] The Pt layer 264, which contains Pt, may contain elements other than Pt, but at least considering the weight ratio of the elements contained in the Pt layer 264, the proportion of Pt is the largest. The Pt layer 264 is in contact with the lower insulating film 50 and the rising Au layer. The Pt layer 264 functions suitably as a diffusion prevention layer. That is, the Pt layer 264 can effectively prevent elements contained in the lower layer or film from moving (diffusing) into the upper Au layer 262. As a result, the Pt layer 264 can prevent problems such as thermal surface deposition of elements from the lower layer in the upper Au layer 262, and maintain the thermal stability of the Au layer 262.

[0057] The Pt layer 264 can be formed on the insulating film 50 by, for example, a thin film formation method such as sputtering or vapor deposition. The thickness of the Pt layer 264 can be, for example, 1 to 500 nm, preferably 5 to 50 nm. If the thickness of the Pt layer 264 is thinner than the predetermined value, it becomes difficult for the Pt layer 264 to form a continuous film, and the diffusion prevention function of the Pt layer 264 deteriorates. On the other hand, if the thickness of the Pt layer 264 is thicker than the predetermined value, disadvantages such as a decrease in throughput due to an increase in film formation time and an increased likelihood of film delamination due to stress occur.

[0058] The insulating film-coated metal member 210 shown in Figure 3 has a reinforcing portion 260 composed of a metal thin film having an Au layer 262 and a Pt layer 264. Therefore, the reinforcing portion 260 can effectively prevent cracks and delamination at the insulating film edge 57 for a longer period of time. In addition, the insulating film-coated metal member 210 has the same effects as the insulating film-coated metal member 10 shown in Figures 1 and 2 in terms of common features with the insulating film-coated metal member 10.

[0059] Third Embodiment Figure 4 is a schematic cross-sectional view of the insulating film-coated metal member 310 according to the third embodiment. The insulating film-coated metal member 310 is the same as the insulating film-coated metal member 210 shown in Figure 3, except that the metal thin film constituting the reinforcing portion 360 has an adhesion layer 366 in addition to the Au layer 262 and the Pt layer 264. The description of the insulating film-coated metal member 310 will focus on the differences from the insulating film-coated metal member 210, and common parts with the insulating film-coated metal member 210 will be denoted by the same reference numerals and their description will be omitted.

[0060] As shown in Figure 4, the reinforcing portion 360 of the insulating film-coated metal member 310 is composed of a thin metal film having multiple layers (three layers in this embodiment) consisting of an Au layer 262, a Pt layer 264, and an adhesion layer 366. The reinforcing portion 360 is stacked in the order of adhesion layer 366, Pt layer 264, and Au layer 262 from the side closest to the insulating film 50, with the adhesion layer 366 being the lowest layer within the reinforcing portion 360.

[0061] The adhesion layer 366 is in contact with the insulating film 50 and has higher adhesion to the insulating film 50 than the other layers included in the reinforcing portion 360, namely the Au layer 262 and the Pt layer 264. Examples of metallic elements included in the adhesion layer 366 include Cr, Ti, Ni, and Mo. Since Cr, Ti, Ni, and Mo have a property of bonding more readily with other elements than metallic elements such as Au and Pt, the adhesion layer 366 containing these metallic elements has high adhesion to the insulating film 50 which contains Si and the like. In addition, Ti has a property of not diffusing easily with Au and is less likely to precipitate on the surface of the Au layer 262, so it is a preferred element to constitute the adhesion layer 366.

[0062] The adhesion layer 366 can be formed on the insulating film 50 by, for example, a thin film formation method such as sputtering or vapor deposition. The thickness of the adhesion layer 366 can be, for example, 1 to 50 nm, preferably 5 to 20 nm. If the thickness of the adhesion layer 366 is thinner than the predetermined value, it becomes difficult for the adhesion layer 366 to form a continuous film, and its function of enhancing adhesion decreases. On the other hand, if the thickness of the adhesion layer 366 is thicker than the predetermined value, disadvantages such as a decrease in throughput due to an increase in film formation time and an increased likelihood of film delamination due to stress occur. The Pt layer 264 of the reinforcing portion 360 is formed on top of the adhesion layer 366.

[0063] The insulating film-coated metal member 310 shown in Figure 4 has an adhesion layer 366 in which the reinforcing portion 360 contacts the insulating film 50. This improves the adhesion between the reinforcing portion 360 and the insulating film 50, and more effectively prevents cracks and peeling at the insulating film edge 57. In addition, the insulating film-coated metal member 310 has the same effects as the insulating film-coated metal member 210 shown in Figure 3 in terms of common features with the insulating film-coated metal member 210.

[0064] Fourth Embodiment Figure 5 is a schematic cross-sectional view of a pressure sensor 400 using an insulating film-coated metal member 410 according to the fourth embodiment. The pressure sensor 400 and the insulating film-coated metal member 410 will be described below with reference to Figures 5 to 7. The insulating film-coated metal member 410 is the same as the insulating film-coated metal member 310 according to the third embodiment, except that the metal member forming the insulating film 50 is a metal stem 420. The insulating film-coated metal member 410 according to the fourth embodiment will be described mainly in terms of the differences from the insulating film-coated metal member 310 shown in Figure 4, and common parts with the insulating film-coated metal member 310 will be denoted by the same reference numerals and their description will be omitted.

[0065] As shown in Figure 5, the pressure sensor 400 includes a metal member 410 with an insulating film, a metal stem 420, a detection unit 430 that detects the amount of deformation of the membrane 422 on the metal stem 420 due to pressure, and an electrode film 436 (see Figure 6) to which intermediate wiring 472 serving as wiring is connected.

[0066] As shown in Figure 5, the metal component of the pressure sensor 400 has a stem shape comprising a membrane 422 having a film-forming surface 422b and a connecting surface 424a connected to the membrane 422. That is, the membrane 422 constitutes an end wall formed at one end of a hollow cylindrical metal stem 420, and the outer surface of the membrane 422 is the film-forming surface 422b. In addition, the outer surface of the cylindrical side wall portion 424 connected to the membrane 422 in the metal stem 420 constitutes the connecting surface 424a connected to the film-forming surface 422b. Since the film-forming surface 422b faces upward and the connecting surface 424a faces sideways, the orientation of the surfaces changes by approximately 90 degrees at the connection position 425 between the film-forming surface 422b and the connecting surface 424a. The other end of the metal stem 420 is an open end of a hollow section, and the hollow section of the metal stem 420 is in communication with the flow path 412b of the connecting member 412.

[0067] In the pressure sensor 400, the fluid introduced into the flow path 412b is guided from the hollow portion of the metal stem 420 to the inner surface 422a of the membrane 422, so that the fluid pressure acts on the membrane 422. The metal stem 420 is made of a metal such as stainless steel, similar to the metal member 20 shown in Figure 1.

[0068] A flange portion 421 is formed around the open end of the metal stem 420 so as to protrude outward from the axis of the metal stem 420. The flange portion 421 is sandwiched between the connecting member 412 and the retaining member 414, sealing the flow path 412b leading to the inner surface 422a of the membrane 422.

[0069] The connecting member 412 has a screw groove 412a for fixing the pressure sensor 400. The pressure sensor 400 is fixed to a pressure chamber containing the fluid to be measured via the screw groove 412a. As a result, the flow path 412b formed inside the connecting member 412 and the inner surface 422a of the membrane 422 in the metal stem 420 are in airtight communication with the pressure chamber containing the fluid to be measured.

[0070] A circuit board 416 is attached to the upper surface of the retaining member 414. The circuit board 416 has a ring-shaped form that surrounds the metal stem 420, but the shape of the circuit board 416 is not limited to this. The circuit board 416 incorporates, for example, a circuit that transmits a detection signal from the detection unit 430.

[0071] As shown in Figure 5, a detection unit 430 is provided on the film-forming surface 422b, which is the outer surface of the membrane 422, via an insulating film 50. The detection unit 430 and the circuit board 416 are connected by intermediate wiring 472, such as wire bonding, and the intermediate wiring 472 ensures electrical conductivity of the detection unit 430 to the outside.

[0072] Figure 6 is a top view of the pressure sensor 400 shown in Figure 5, viewed from above the film-forming surface 422b of the membrane 422. Figure 7 is a cross-sectional view of the pressure sensor 400 shown in Figure 6, along the cross-sectional line VII-VII. However, in Figures 6 and 7, the flange portion 421 of the metal stem 420, the circuit board 416, and the intermediate wiring 472 are omitted from the illustration. As shown in Figures 6 and 7, a detection portion 430 is formed in the first insulating film portion 54 of the insulating film-coated metal member 410.

[0073] As shown in Figures 5 and 6, the detection unit 430 is formed on the upper side of the film-forming surface 422b of the metal stem 420, on the opposite side from the film-forming surface 422b, with the insulating film 50 in between. As shown in Figure 6, the detection unit 430 has resistors R1, R2, R3, and R4 connected by electrical wiring 434. The electrical wiring 434 and resistors R1 to R4 of the detection unit 430 are made of strain-resistant film 432.

[0074] Furthermore, the electrode film 436 is formed on the upper side of the first insulating film portion 54, similar to the detection unit 430. The electrode film 436 is formed so as to overlap a part of the detection unit 430 (for example, the strain resistance film 432) from above, and is electrically and physically connected to the detection unit 430. In addition, the intermediate wiring 472 shown in Figure 1 is connected to the electrode film 436, and the detection signal from the detection unit 430 is transmitted to the circuit board 416 via the electrode film 436 and the intermediate wiring 472.

[0075] The resistors R1 to R4 of the detection unit 430 are formed at predetermined positions on the membrane 422, and generate strain in accordance with the deformation of the membrane 422, causing the resistance value to change. These resistors R1 to R4 are connected by electrical wiring 434 to form a Wheatstone bridge circuit. Such a detection unit 430 detects the amount of deformation of the membrane 422, which is one of the physical quantities related to the metal stem 420, and detects the pressure of the fluid in contact with the inner surface 422a of the membrane 422 (see Figure 5).

[0076] As shown in Figure 7, the resistors R1 to R4 and electrode film 436 constituting the detection unit 430 are insulated from the metal stem 420 by the insulating film 50 formed on the film-forming surface 422b and the connection surface 424a. Furthermore, as shown in Figures 6 and 7, an insulating protective film 474 is formed on the upper side of the first portion 54 of the insulating film, covering the detection unit 430 from above. However, at least a portion of the electrode film 436 is exposed from the protective film 474. The thickness, material, and formation method of the protective film 474 are not particularly limited, but can be the same as those of the insulating film 50, for example.

[0077] The strain resistance film 432, which constitutes resistors R1 to R4 and electrical wiring 434, can be fabricated, for example, by patterning a conductive thin film of a predetermined material. The strain resistance film 432 contains Cr and Al, preferably 50 to 99 at% Cr and 1 to 50 at% Al, and more preferably 70 to 90 at% Cr and 5 to 30 at% Al. The inclusion of Cr and Al in the strain resistance film 432 stabilizes the TCR (Temperature coefficient of Resistance) and TCS (Temperature coefficient of Sensitivity) in high-temperature environments, enabling highly accurate pressure detection. Furthermore, by setting the Cr and Al content within a predetermined range, a high gauge factor and good temperature stability can be achieved at a higher level.

[0078] The strain resistance film 432 may contain elements other than Cr and Al; for example, the strain resistance film 432 may contain O and N. The O and N contained in the strain resistance film 432 may be those that remained in the reaction chamber during the deposition of the strain resistance film 432 and were incorporated into the strain resistance film 432. Alternatively, the O and N contained in the strain resistance film 432 may be intentionally introduced into the strain resistance film 432, for example, by being used as an atmospheric gas during deposition or annealing.

[0079] As shown in Figure 7, the electrode film 436 has a contact layer 436a superimposed on the strain resistance film 432, a diffusion prevention layer 436b superimposed on the contact layer 436a, and a mounting layer 436c superimposed on the diffusion prevention layer 436b. The electrode film 436 has a multilayer structure composed of multiple layers made of different materials. However, the electrode film 436 is not limited to the three-layer structure shown in Figure 7, and the electrode film 436 may have a one-layer, two-layer, or four-layer or more stacked structure.

[0080] As shown in Figure 7, the contact layer 436a, which is the lowest layer of the electrode film 436, is in direct contact with the strain resistance film 432. It is preferable that the contact layer 436a ensures an ohmic connection with the strain resistance film 432 to improve the electrical characteristics of the detection unit 430. In addition, the contact layer 436a ensures the adhesion strength between the strain resistance film 432 and the electrode film 436 to prevent peeling defects of the film and layer.

[0081] The contact layer 436a can be formed by thin-film formation methods such as sputtering or vapor deposition. The thickness of the contact layer 436a is not particularly limited, but is, for example, 1 to 50 nm, preferably 5 to 20 nm. The contact layer 436a preferably contains at least one of Cr, Ti, Ni, and Mo. Since these elements readily form alloys with other metals, a contact layer 436a containing such elements can ensure adhesion strength with the strain-resistant film 432 and the diffusion-preventing layer 436b, thereby preventing delamination defects between the film and the layers.

[0082] Furthermore, it is particularly preferable that the contact layer 436a contains Ti. Ti does not easily diffuse into the mounting layer 436c which contains Au or the like, and tends not to precipitate on the upper surface of the mounting layer 436c. Therefore, the electrode film 436 having a contact layer 436a containing Ti exhibits good adhesion to the intermediate wiring 472 even after the electrode film 436 has been exposed to a high-temperature environment.

[0083] Furthermore, since Ti does not easily diffuse into Cr, the Ti constituting the contact layer 436a has the characteristic of not easily diffusing into the strain resistance film 432 containing Cr and Al, even in high-temperature environments. Therefore, by including Ti in the contact layer 436a, the detection unit 430 can prevent the diffusion of elements in the electrode film 436 into the strain resistance film 432, even when used in high-temperature environments, and can prevent a decrease in the performance of the strain resistance film 432 due to compositional changes.

[0084] As shown in Figure 7, the diffusion prevention layer 436b is positioned between the contact layer 436a and the mounting layer 436c in the electrode film 436, and is sandwiched vertically by the mounting layer 436c and the contact layer 436a. The diffusion prevention layer 436b prevents elements contained in films and layers located below the diffusion prevention layer 436b, such as the strain resistance film 432 and the contact layer 436a, from diffusing into the mounting layer 436c located above the diffusion prevention layer 436b, and also prevents them from precipitation on the upper surface of the mounting layer 436c.

[0085] The diffusion prevention layer 436b can be formed by thin-film formation methods such as sputtering or vapor deposition. The thickness of the diffusion prevention layer 436b is not particularly limited, but is, for example, 1 to 500 nm, and preferably 5 to 50 nm. If the thickness of the diffusion prevention layer 436b is too thin, it becomes difficult to form a continuous film, and the diffusion prevention function may be weakened. If the thickness is too thick, problems such as film delamination may occur, or problems such as a decrease in productivity (throughput) due to an increase in film formation time may occur.

[0086] It is preferable that the diffusion-blocking layer 436b contains a transition element belonging to the 5th or 6th period, from the viewpoint of preventing the diffusion of elements contained in the strain resistance film 432 or contact layer 436a to the upper layer. Specifically, it is preferable that the diffusion-blocking layer 436b contains one or more elements selected from Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, and Au.

[0087] Furthermore, it is even more preferable that the diffusion prevention layer 436b contains platinum group elements. Specifically, it is preferable that the diffusion prevention layer 436b contains one or more elements selected from Ru, Rh, Pd, Os, Ir, and Pt. Because platinum group elements have low reactivity and are chemically stable, the diffusion prevention layer 436b containing platinum group elements exhibits a particularly suitable diffusion prevention effect even in high-temperature environments. Among the platinum group elements, Pt in particular has a proven track record of use in other electrode fields and has more accumulated technology than other platinum group elements.

[0088] As shown in Figure 2, the uppermost mounting layer 436c of the electrode film 436 is exposed on the upper surface of the electrode film 436. Intermediate wiring 472, composed of fine wires such as Au or Al, is joined to the mounting layer 436c by wire bonding or the like. Pressure sensors 400 using intermediate wiring 472 made of fine wires of Au or Al can be used even in high-temperature environments above the melting point of solder, and have good heat resistance. Furthermore, pressure sensors 400 using intermediate wiring 472 made of fine wires of Au can have improved heat resistance compared to pressure sensors using intermediate wiring 472 made of fine wires of Al.

[0089] The mounting layer 436c can be formed by thin-film formation methods such as sputtering or vapor deposition. The thickness of the mounting layer 436c is not particularly limited, but is, for example, 10 to 400 nm, preferably 100 to 300 nm. If the mounting layer 436c is too thin, it becomes difficult to form a continuous film, and the adhesion to the intermediate wiring 472 may decrease. If the mounting layer 436c is too thick, problems such as film delamination may occur, or productivity (throughput) may decrease due to increased film formation time.

[0090] It is preferable that the mounting layer 436c contains at least one of Au, Al, or Ni from the viewpoint of heat resistance and bonding with the intermediate wiring 472. Furthermore, from the viewpoint of improving heat resistance and further enhancing adaptability to high-temperature environments, it is even more preferable that the mounting layer 436c contains Au, which has low resistance and a high melting point even in high-temperature environments. In addition, when fine wires of Au are used as the material for the intermediate wiring 472, the inclusion of Au in the mounting layer 436c means that both the intermediate wiring 472 and the mounting layer 436c are made of Au. This improves the adhesion of the bonding portion between the intermediate wiring 472 and the mounting layer 436c.

[0091] As shown in Figures 6 and 7, the insulating film-coated metal member 410 of the pressure sensor 400 has a reinforcing portion 360 similar to that of the insulating film-coated metal member 310 shown in Figure 4. That is, the reinforcing portion 360 is formed along the insulating film edge 57 and covers the insulating film edge 57 except for the interrupted portion 360a. Furthermore, the reinforcing portion 360 of the insulating film-coated metal member 410 is composed of a thin metal film having an adhesion layer 366, a Pt layer 264, and an Au layer 262.

[0092] Furthermore, as shown in Figures 6 and 7, the detection unit 430 and electrode film 436, which are placed on the first insulating film portion 54, are positioned at a predetermined distance from the reinforcing portion 360. By positioning the detection unit 430 and electrode film 436 at a distance from the reinforcing portion 360, insulation between the detection unit 430 and electrode film 436 and the reinforcing portion 360 is ensured.

[0093] The metal thin film constituting the reinforcing portion 360 shown in Figure 7 preferably includes layers common to at least a portion of the layers included in the electrode film 436. For example, the Au layer 262 of the reinforcing portion 360 and the mounting layer 436c of the electrode film 436 can be common layers with substantially the same constituent elements, including Au. Similarly, the Pt layer 264 of the reinforcing portion 360 and the diffusion prevention layer 436b of the electrode film 436 can be common layers with substantially the same constituent elements, including Pt. Furthermore, the adhesion layer 366 of the reinforcing portion 360 and the contact layer 436a of the electrode film 436 can be common layers with substantially the same constituent elements, including Ti, etc.

[0094] Furthermore, as shown in Figure 7, if both the metal thin film constituting the reinforcing portion 360 and the electrode film 436 have multiple layers and multiple common layers, it is preferable that the vertical relationship of the multiple common layers coincides between the reinforcing portion 360 and the electrode film 436. Since the common layers of such a reinforcing portion 360 and electrode film 436 can be formed in the same process, good productivity is achieved.

[0095] Furthermore, the reinforcing portion 360 and the electrode film 436 may share all the same constituent layers, and the layer-to-layer relationship (stack order) may also match. In such a pressure sensor 400, the reinforcing portion 360 and the electrode film 436 can be formed using the same process. In this case, the metal thin film constituting the reinforcing portion 360 is not limited to a three-layer structure of Au layer 262, Pt layer 264, and adhesion layer 366, but can be any metal multilayer film common to the electrode film 436.

[0096] In the pressure sensor 400 shown in Figure 1, a metal stem 420 having a membrane 422 is used as the metal component of the insulating film-coated metal component 410. Such a metal stem 420 can effectively propagate pressure to the detection unit 430, thereby improving the sensitivity of the pressure sensor 400. In addition, in the pressure sensor 400, an insulating film 50 is formed on the film-forming surface 422b and the connection surface 424a, which are the outer surfaces of the metal stem 420, and a reinforcing portion 360 is formed to prevent the occurrence of cracks and delamination in the insulating film 50. Such a pressure sensor 400 can ensure good detection accuracy and reliability even in environments requiring high durability, such as high-temperature and high-pressure environments.

[0097] Furthermore, the insulating film-coated metal member 410 included in the pressure sensor 400 has the same effects as the insulating film-coated metal member 310 shown in Figure 4, in terms of their commonalities. It goes without saying that this disclosure includes many other embodiments and modifications in addition to the embodiments and examples described above. For example, in the fourth embodiment, a pressure sensor 400 in which a detection unit 430 detects the amount of deformation of the membrane 422 due to pressure was described as an example, but the detection unit 430 is not limited to detecting the amount of deformation due to pressure. Examples of physical quantity sensors having an insulating film-coated metal member 410 and a detection unit include those that detect other physical quantities related to the metal member, such as strain, temperature, or vibration, in addition to the pressure sensor 400. [Explanation of Symbols]

[0098] 10, 110, 210, 310, 410… Metal components with insulating film 20… Metal components 22b, 422b...film forming surface 24a, 424a... connection surface 25, 425… Connection location 50… Insulating film 54…Insulating film, first part 56...Second part of insulating film 57…Insulating film edge 60, 160, 260, 360... Reinforcement parts 60a, 360a... gaps 262…Au layer 264...Pt layer 366... ​​Close contact layer 400... Pressure sensor 412...Connecting member 412a... Thread groove 412b...channel 414…Retaining member 416... Circuit board 420…Metal stem 421...Flange section 422...Membrane 424... Side wall section 430...Detection unit 432... Distortion Resistive Film R1~R4…Resistance 434…Electrical wiring 436...Electrode film 436a... Contact layer 436b... Diffusion prevention layer 436c…Implementation layer 472...Intermediate wiring 474...Protective film

Claims

1. A metal member having a film-forming surface and a connecting surface that faces a different direction from the film-forming surface and connects to the film-forming surface, An insulating film covering at least a portion of the film-forming surface and the connecting surface, spanning the connection position between the film-forming surface and the connecting surface, The insulating film is formed along the insulating film edge, which is the portion that covers the connection position, and includes a reinforcing portion that covers at least a part of the insulating film edge from the side opposite to the metal member, It has a detection unit formed on the side of the insulating film opposite to the surface facing the film-forming surface, which detects a physical quantity related to the metal member, The detection unit is a physical quantity sensor that is positioned at a distance from the reinforcing unit and is insulated from the reinforcing unit.

2. The reinforcing portion is made of a thin metal film, as described in claim 1.

3. The physical quantity sensor according to claim 2, wherein the metal thin film has an Au layer containing Au.

4. The physical quantity sensor according to claim 2 or 3, wherein the metal thin film has a Pt layer containing Pt.

5. A metal member having a film-forming surface and a connecting surface that faces a direction different from the film-forming surface and is connected to the film-forming surface, An insulating film covering at least a portion of the film-forming surface and the connecting surface, spanning the connection position between the film-forming surface and the connecting surface, The insulating film has a reinforcing portion formed along the insulating film edge, which is the portion that covers the connection position, and covers at least a part of the insulating film edge from the side opposite to the metal member, The reinforcing portion is made of a thin metal film. The aforementioned metal thin film has multiple layers, The metal thin film is in contact with the insulating film and has an adhesion layer that has higher adhesion to the insulating film than other layers, making it a metal member with an insulating film.

6. The electrode film is formed so as to overlap a part of the detection unit from above, and a wiring portion is connected to the detection unit to ensure electrical conductivity to the outside of the detection unit, The physical quantity sensor according to any one of claims 2 to 4, wherein the metal thin film of the reinforcing portion includes a layer common to at least a portion of the layers included in the electrode film.

7. The metal member has a stem shape comprising a membrane having the film-forming surface and a side wall portion having the connecting surface, The detection unit is a physical quantity sensor according to any one of claims 2 to 4, which detects the amount of deformation of the membrane.

8. The metal member has a stem shape comprising a membrane having the film-forming surface and a side wall portion having the connecting surface, The detection unit detects the amount of deformation of the membrane due to pressure, as described in any one of claims 2 to 4.

9. The physical quantity sensor according to any one of Claims 1 to 4, wherein the metal member has a stem shape comprising a membrane having the film-forming surface and a side wall portion having the connecting surface, and the insulating film edge portion is a portion that covers the connection position between the film-forming surface facing upward and the connecting surface facing sideways.

10. The reinforcing portion is formed in a strip shape along the edge of the insulating film, as described in any one of Claims 1 to 4.

Images