Peeling sensor, method for manufacturing peeling sensor, and electronic apparatus

Abstract

A peeling sensor (100, 200, 300, 400) according to the present disclosure is provided with a board (1), a wiring member (3) disposed on the board (1), and a sealing member (2) for sealing the wiring member (3). The sensor is characterized in that the bonding interface between the board (1) and the wiring member (3) has a first bonding interface (11a) and a second bonding interface (12a), and the bonding strength between the board (1) and the wiring member (3) is lower at the second bonding interface (12a) than at the first bonding interface (11a).

Description

Peel sensor, peel sensor manufacturing method, and electronic device

[0001] The present disclosure relates to a peel sensor and an electronic device equipped with the peel sensor.

[0002] To prevent deterioration due to water vapor and corrosive substances present in the external environment, structures such as wiring components and semiconductors are sometimes sealed on substrates with sealing materials. Sealing materials are sometimes made of gas-permeable materials such as resins. However, if the sealing material seals the internal structure, even if water vapor or corrosive substances penetrate the sealing material, they remain in a gaseous state, resulting in little corrosion of the internal structure. On the other hand, if the sealing material and the substrate peel at their bonding interface, the water vapor that penetrates the interior forms a water film at the peeled area, and the corrosive substances dissolve, causing corrosion. To prevent such problems, a peel sensor has been proposed that detects peeling at the bonding interface between the sealing material and the substrate.

[0003] One such peel sensor is disclosed as including a metal test piece, a separator made of an insulating material and having liquid permeability disposed on the metal test piece, an auxiliary electrode disposed on the separator, and a resin test piece made of resin that liquid-tightly encapsulates the separator and auxiliary electrode and is joined to the metal test piece. This peel sensor can detect peeling that may occur at the joint interface between the metal test piece and the resin test piece by measuring the electrical characteristics between the metal test piece and the auxiliary electrode (for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2020-038178

[0005] However, the above-mentioned peel sensor had the problem that even if the sealing member and the substrate are not peeled off, if corrosive gases or water vapor from the external environment permeate the resin and enter the interior, the electrical properties of the separator change, which could result in a false detection of peeling between the sealing member and the substrate.

[0006] The peel sensor according to the present disclosure comprises a substrate, a wiring member arranged on the substrate, and a sealing member that seals the wiring member, and is characterized in that the bonding interface between the substrate and the wiring member has a first bonding interface and a second bonding interface, and the second bonding interface has a lower adhesion strength between the substrate and the wiring member than the first bonding interface.

[0007] In addition, the manufacturing method of a peel sensor according to the present disclosure includes a step of forming a wiring member on a substrate and a step of sealing the wiring member with a sealing member, and is characterized in that the bonding interface between the substrate and the wiring member has a first bonding interface and a second bonding interface which have different adhesion strengths between the substrate and the wiring member, and the second bonding interface has a lower adhesion strength between the substrate and the wiring member than the first bonding interface.

[0008] According to the configuration of the present disclosure, a peel sensor is provided that can detect peeling between a sealing member and a substrate, and that has a low probability of false detection when the sealing member and the substrate are not peeled.

[0009] a cross-sectional view of the peel sensor according to the first embodiment when the substrate 1 and the sealing member 2 are not peeled off; a cross-sectional view of the peel sensor according to the first embodiment when the substrate 1 and the sealing member 2 are peeled off and the wiring member 3 is deformed; a cross-sectional view of the peel sensor according to the first embodiment when the substrate 1 and the sealing member 2 are peeled off and the wiring member 3 is broken; a flowchart of a manufacturing method of the peel sensor according to the first embodiment; a schematic front view showing one step of the manufacturing method of the peel sensor according to the first embodiment; a flowchart of a modified example 1 of the manufacturing method of the peel sensor according to the first embodiment; a front view showing the positional relationship between the substrate 1 and the thin film 6 after the S1b step; a front view showing the positional relationship between the substrate 1, the wiring member 3, and the thin film 6 after the S2b step; a front view showing the positional relationship between the substrate 1, the wiring member 3, and the thin film 6 after the S3b step; a flowchart of a modified example 2 of the manufacturing method of the peel sensor according to the first embodiment; a plan view of the peel sensor according to the second embodiment; a plan view of the peel sensor according to the third embodiment; a plan view of the peel sensor according to the fourth embodiment;

[0010] The details of the embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts will be denoted by the same reference numerals, and redundant explanations will not be repeated. Note that the embodiments described below are merely examples, and the scope of the present disclosure is not limited to the embodiments described below.

[0011] First Embodiment A peel sensor 100 according to a first embodiment will be described below.

[0012] FIG. 1 is an oblique external view of a peel sensor according to a first embodiment. The peel sensor 100 is composed of a substrate 1, a sealing member 2, a wiring member 3 (not shown in FIG. 1 ), and terminals 4, and detects peeling between the substrate 1 and the sealing member 2. Although not shown in FIG. 1 , the wiring member 3 is disposed on the substrate 1 inside the sealing member 2, and terminals 4 are connected to both ends of the wiring member 3. The terminals 4 protrude from the sealing member 2 and can be connected to an external device for measuring electrical characteristics (such as a resistance meter, an ammeter, or a voltmeter, not shown in FIG. 1 ) to measure changes in the electrical characteristics of the wiring member 3 and detect peeling.

[0013] FIG. 2 is an oblique external view of the peel sensor according to the first embodiment, with the sealing member 2 not shown. The peel sensor 100 includes a substrate 1, a wiring member 3, and terminals 4. The wiring member 3 is disposed on the substrate 1, and terminals 4 are connected to both ends of the wiring member 3. As shown in FIG. 2, the wiring member 3 has a first portion 31 and a second portion 32. The first portion 31 and the second portion 32 have different adhesion strengths at their bonding interfaces with the substrate 1. Specifically, the bonding interface between the second portion 32 and the substrate 1 has a lower adhesion strength than the bonding interface between the first portion 31 and the substrate 1. This relationship in adhesion strength can be achieved by performing a surface treatment or forming a thin film on either or both of the first portion 31 and the second portion 32. For convenience, the first portion 31 and the second portion 32 are marked with different diagonal lines to distinguish them from each other. However, the presence or absence of the patterns does not limit the scope of the present embodiment.

[0014] The substrate 1 may be, for example, a metal lead frame or a printed circuit board, and various semiconductor chips, metal wiring, or electronic components may be mounted on it. The form (shape, size, etc.) of the substrate 1 can be selected arbitrarily. The material of the substrate may be a conductor such as metal, or an insulator such as ceramic or resin. For example, the substrate may be composed of two or more alloys, such as a multilayer structure of two or more layers such as nickel (Ni) / copper (Cu), or a material composed of two or more compositions such as an iron (Fe)-Ni alloy. The substrate 1 may also be subjected to surface treatments such as coating with a film (painting, plating, physical vapor deposition (PVD), chemical vapor deposition (CVD), chemical conversion treatment, oxidation treatment, etc.). Other surface treatments may also be applied, such as polishing, cleaning (barrel processing, blasting, etc.), light irradiation including ultraviolet light or visible light, hydrophobicization, or hydrophilization. If the substrate 1 is a conductor, it is required to be insulated from the wiring member 3 in order to measure the electrical characteristics of the wiring member 3. For example, if the substrate 1 is a metal, it is desirable to perform an insulating treatment such as covering the entire surface with an insulating film or covering only the portions that come into contact with the wiring member 3 with an insulating film.

[0015] The sealing member 2 has the function of sealing and protecting the internal structure, such as the wiring member 3 and semiconductor chips, arranged on the substrate 1. The sealing member 2 uses an epoxy resin, phenolic resin, silicone resin, or the like, but may also use a resin-based adhesive that bonds the metal substrate to other structures, or may be composed of two or more materials. The sealing member 2 may also contain additives such as fillers and flame retardants. The sealing method may be filling (potting) into the metal substrate or integral molding with the metal substrate (insert molding, etc.).

[0016] The wiring member 3 is made of a metal material with good conductivity, such as aluminum (Al) or copper (Cu). The wiring member 3 can be formed (disposed) on the substrate 1 by forming a film of these metal materials on the substrate 1 using a sputtering method, plating method, vapor deposition method, or the like. Alternatively, the wiring member 3 may be formed (disposed) on the substrate 1 in the form of a ribbon, wire, or a plate-like member such as an aluminum plate or copper plate. The wiring member 3 has a first portion 31 and a second portion 32. The first portion 31 and the second portion 32 have different adhesion strengths at their bonding interfaces with the substrate 1. Specifically, the bonding interface between the second portion 32 and the substrate 1 has a lower adhesion strength than the bonding interface between the first portion 31 and the substrate 1. This adhesive strength relationship can be achieved by performing a surface treatment or forming a thin film on one or both of the first portion 31 and the second portion 32. The wiring member 3 may have a portion other than the first portion 31 and the second portion 32 that has a different adhesion strength from the first portion 31 and the second portion 32 at their bonding interface with the substrate 1.

[0017] The terminals 4 are used to connect the wiring member 3 to a device for measuring electrical characteristics. The terminals 4 are made of a metal material with good conductivity, such as copper (Cu). The terminals 4 may be disposed on the substrate 1, or may be disposed so as to penetrate the interior of the sealing member 2. It is also desirable that the terminals 4 be provided with an adhesive strength that will prevent them from peeling off from adjacent members.

[0018] The peel sensor 100 is for detecting peeling between the substrate 1 and the sealing member 2. The peel sensor 100 may be disposed adjacent to or inside an electronic component or electronic device for which failure should be prevented. The peel sensor 100 may be used alone or multiple sensors may be used simultaneously.

[0019] FIG. 3 is a cross-sectional view of the peel sensor according to the first embodiment when the substrate 1 and the sealing member 2 are not peeled off. The wiring member 3 has a first portion 31 and a second portion 32. As shown in FIG. 3 , the bonding interface between the first portion 31 of the wiring member 3 and the substrate 1 is defined as a first bonding interface 11a. The bonding interface between the second portion 32 of the wiring member 3 and the substrate 1 is defined as a second bonding interface 12a. Regarding the adhesion strength between the wiring member 3 and the substrate 1, the adhesion strength of the second bonding interface 12a is lower than that of the first bonding interface 11a. In other words, peeling between the wiring member 3 and the substrate 1 is more likely to occur at the second bonding interface 12a than at the first bonding interface 11a. Therefore, peeling between the substrate 1 and the wiring member 3 first occurs at the second bonding interface 12a. In other words, in the early stages of peeling, only the second bonding interface 12a is peeled off, and the first bonding interface 11a is not peeled off. At the bonding interface between the substrate 1 and the wiring member 3, there may be a bonding interface having a different adhesion strength other than the first bonding interface 11a and the second bonding interface 12a.

[0020] FIG. 4 is a cross-sectional view of the peel sensor according to the first embodiment, in which the substrate 1 and the sealing member 2 peel off and the wiring member 3 is deformed. When the peel sensor 100 is exposed to an environment such as high temperature, high humidity, temperature cycles, or the presence of corrosive substances, peeling may occur at the bonding interface 10 between the substrate 1 and the sealing member 2 and at the second bonding interface 12a between the wiring member 3 and the substrate 1, as shown in FIG. 4 . Meanwhile, no peeling occurs at the first bonding interface 11a in the figure. This situation occurs because, as described in FIG. 3 , the second bonding interface 12a has a lower adhesion strength than the first bonding interface 11a. Furthermore, if the bonding interface 10 and the second bonding interface 12a are adjusted to have similar adhesion strengths, this situation is more likely to occur. In this situation, stress is applied between the first portion 31 and the second portion 32 of the wiring member 3, resulting in breakage or deformation of the wiring member 3. FIG. 4 is a diagram showing a deformed pattern of the wiring member 3.

[0021] When the wiring member 3 is deformed in this manner, electrical characteristics such as the resistance value of the wiring member 3 itself and the current value and voltage value measured by the peel sensor 100 change. Furthermore, when the wiring member 3 is deformed, the substrate 1 and the sealing member 2 are peeled off (see FIG. 4). Therefore, peeling between the substrate 1 and the sealing member 2 can be detected based on the change in electrical characteristics due to the deformation of the wiring member 3. Furthermore, as described above, the change in the electrical characteristics of the wiring member 3 is premised on peeling between the substrate 1 and the sealing member 2, and therefore the peel sensor 100 is unlikely to make a false detection when the substrate 1 and the sealing member 2 are not peeled off.

[0022] Furthermore, if the second bonding interface 12a between the wiring member 3 and the substrate 1 peels off, the second portion 32 of the wiring member 3 is no longer in close contact with the substrate 1, and therefore the heat generated when current is applied to the wiring member 3 is not sufficiently dissipated to the substrate 1, causing the temperature of the wiring member 3 to rise. Because there is a correlation between the temperature and the electrical characteristics of the wiring member (if the wiring member is made of metal, an increase in the temperature of the wiring member increases the resistance of the wiring member), a change in the electrical characteristics occurs when the temperature of the wiring member 3 rises. Peeling between the substrate 1 and the sealing member 2 can also be detected from this change in the electrical characteristics.

[0023] It is desirable that the adhesion strength of the second bonding interface 12a between the wiring member 3 and the substrate 1 is approximately the same as the adhesion strength of the bonding interface 10 between the sealing member 2 and the substrate 1. Due to this relationship, peeling at the bonding interface 10 between the sealing member 2 and the substrate 1 and peeling at the second bonding interface 12a between the wiring member 3 and the substrate 1 occur at approximately the same time. This reduces the time lag between peeling at the bonding interface 10 between the sealing member 2 and the substrate 1 and the occurrence of deformation or disconnection of the wiring member 3 (associated with peeling at the bonding interface 12a between the wiring member 3 and the substrate 1), and peeling between the sealing member 2 and the substrate 1 can be detected promptly.

[0024] Moreover, it is desirable that the adhesion strength of the second bonding interface 12 a between the wiring member 3 and the substrate 1 be lower than the adhesion strength of the bonding interface 12 b between the wiring member 3 and the sealing member 2. This is because the location of peeling due to deformation or disconnection of the wiring member 3 is not the bonding interface 12 b but the second bonding interface 12 a.

[0025] Furthermore, it is desirable that the adhesion strength of the first bonding interface 11a between the wiring member 3 and the substrate 1 be higher than that of the bonding interface 11b between the wiring member 3 and the sealing member 2. From the viewpoint of the present disclosure, which is to detect peeling between the substrate 1 and the sealing member 2 based on a change in electrical characteristics associated with deformation or disconnection of the wiring member 3, it is preferable that peeling is less likely to occur at the first bonding interface 11a than at other bonding interfaces including the bonding interface 11b. In other words, because deformation or disconnection of the wiring member 3 occurs when the first bonding interface 11a is not peeled but the second bonding interface 12a is peeled, it is preferable that peeling is as less likely to occur at the first bonding interface 11a as possible.

[0026] FIG. 5 is a cross-sectional view of the peel sensor according to the first embodiment, in which the substrate 1 and the sealing member 2 are peeled off and the wiring member 3 is broken. When the peel sensor 100 is exposed to an environment such as high temperature, high humidity, temperature cycles, or the presence of corrosive substances, peeling may occur at the bonding interface 10 between the substrate 1 and the sealing member 2 and at the second bonding interface 12a between the wiring member 3 and the substrate 1, as shown in FIG. 5 . Meanwhile, no peeling occurs at the first bonding interface 11a in the figure. This situation occurs because, as described in FIG. 3 , the second bonding interface 12a has a lower adhesion strength than the first bonding interface 11a. In this situation, stress is applied between the first portion 31 and the second portion 32 of the wiring member 3, resulting in a break or deformation of the wiring member 3. FIG. 5 illustrates a pattern in which the wiring member 3 is broken. Note that this situation is more likely to occur if the bonding interface 10 and the second bonding interface 12a are adjusted to have similar adhesion strengths.

[0027] 5, when the wiring member 3 is broken, electrical characteristics such as the resistance value of the wiring member 3 itself and the current value and voltage value measured by the peel sensor 100 change. Furthermore, when the wiring member 3 is broken, the substrate 1 and the sealing member 2 are peeled off (see FIG. 5). Therefore, peeling between the substrate 1 and the sealing member 2 can be detected based on the change in electrical characteristics due to the break in the wiring member 3. Furthermore, as described above, the change in the electrical characteristics of the wiring member 3 is premised on peeling between the substrate 1 and the sealing member 2, and therefore the peel sensor 100 is unlikely to make a false detection when the substrate 1 and the sealing member 2 are not peeled off.

[0028] <Method for Manufacturing Peel Sensor> A method for manufacturing the peel sensor according to embodiment 1 will be described below. Note that the peel sensor according to this embodiment may be manufactured by a method other than this method.

[0029] FIG. 6 is a flowchart of the method for manufacturing a peel sensor according to the first embodiment. FIG. 7 is a schematic front view showing one step of the method for manufacturing a peel sensor according to the first embodiment. In the method for manufacturing a peel sensor according to this embodiment, a step (S1a) of performing a surface treatment on a substrate 1 is first performed. As shown in FIG. 7 , a surface treatment is performed by ultraviolet irradiation or CVD (Chemical Vapor Deposition) on an arbitrary portion of the surface on which the wiring member 3 is formed on the substrate 1 (the portion indicated by the dotted arrow in FIG. 7 ), and other portions are masked with a masking member 5 to prevent the surface treatment. The masking member 5 can be any type, such as masking tape, and is removed after the surface treatment is completed.

[0030] Any method of surface treatment may be used, but when surface treatment that improves adhesion strength is performed, the surface that has been surface-treated corresponds to the first bonding interface 11a between the wiring member 3 and the substrate 1, and the surface that has not been surface-treated corresponds to the second bonding interface 12a. This is because, as described in FIG. 3 , the second bonding interface 12a has lower adhesion strength than the first bonding interface 11a (because the first bonding interface 11a has higher adhesion strength than the second bonding interface 12a).

[0031] An example of a surface treatment that improves adhesion strength is ultraviolet irradiation. Conversely, if a surface treatment that reduces adhesion strength is performed, the surface that has been surface-treated corresponds to the second bonding interface 12a, and the surface that has not been surface-treated corresponds to the first bonding interface 11a. The surface treatment may be light irradiation such as visible light other than ultraviolet irradiation, polishing or cleaning (barrel processing, blasting, etc.), or other hydrophobic or hydrophilic treatment. Furthermore, surface treatment may be performed under different conditions on both the arbitrary surface and the other surface of the substrate 1 without using a masking member.

[0032] Next, a step (S2a) is carried out to form the wiring member 3 on the substrate 1. The wiring member 3 is formed on the surface of the substrate 1 that has been subjected to the above-described step S1a, so as to include both a surface-treated surface and a surface that has not been subjected to surface treatment. The method for forming the wiring member 3 on the substrate 1 may be electrolytic plating, electroless plating, vacuum deposition, sputtering, or the like.

[0033] After the wiring member 3 is formed on the substrate 1, the adhesion strength of the first bonding interface 11 a and the second bonding interface 12 a between the wiring member 3 and the substrate 1 may be checked. In this case, it is preferable to use a method of measuring the force applied to each bonding interface when peeling occurs in a tensile test, a peel test, a shear test, or the like, or a method of measuring the time until peeling occurs in an operational test such as a heat cycle test.

[0034] Furthermore, a step (S3a) of joining terminals 4 to wiring member 3 is carried out. Terminals 4 are joined to both ends of wiring member 3 by soldering or the like. The joining method may be ultrasonic joining or the like.

[0035] Finally, a step (S4a) is carried out to seal the wiring member 3 with the sealing member 2. The sealing method may be transfer molding, insert molding, potting or the like.

[0036] Through these steps S1a to S4a, the peel sensor according to the first embodiment is manufactured.

[0037] <Modification 1 of the manufacturing method of the peel-off sensor> Next, a description will be given of Modification 1 of the manufacturing method of the peel-off sensor according to the embodiment 1. In the manufacturing method according to Modification 1, thin film formation and selective etching are performed instead of the surface treatment performed in the manufacturing method described above.

[0038] FIG. 8 is a flowchart of a first modification of the manufacturing method of the peel sensor according to the first embodiment. In the first modification of the manufacturing method of the peel sensor according to the present embodiment, first, a step (S1b) of forming a thin film 6 on a substrate 1 is performed. FIG. 9 is a front view showing the positional relationship between the substrate 1 and the thin film 6 after the step S1b. As shown in FIG. 9, after the step S1b, the thin film 6 is formed on the surface of the substrate 1 on which the wiring member 3 is to be formed. The thin film 6 is, for example, silicon oxide (SiO2). The thin film 6 is formed by CVD (Chemical Vapor Deposition), oxidation treatment, or the like. A portion of the thin film 6 is selectively etched as a sacrificial layer in a subsequent step (S3b).

[0039] Next, a step (S2b) of forming wiring members 3 on substrate 1 is carried out. Fig. 10 is a front view showing the positional relationship between substrate 1, wiring members 3, and thin film 6 after step S2b. As shown in Fig. 10, after step S2b, wiring members 3 are formed on the surface of substrate 1 on which thin film 6 has been formed in step S1b. The wiring members 3 may be formed on substrate 1 by electrolytic plating, electroless plating, vacuum deposition, sputtering, or the like.

[0040] Thereafter, a step (S3b) is carried out in which the thin film 6 is selectively etched as a sacrificial layer. Any type of etchant can be used, such as hydrofluoric acid (HF), but the respective materials and properties should be selected taking into consideration conditions such as etching rate and etching time so that only the thin film 6 is etched and the substrate 1 and wiring member 3 are not etched. Conditions such as etching time are set so that only a desired portion of the thin film 6 is selectively etched (so that the entire thin film 6 is not etched).

[0041] FIG. 11 is a front view showing the relative positions of the substrate 1, wiring member 3, and thin film 6 after step S3b. After step S3b, in the area where the thin film 6 was removed by etching, the wiring member 3 comes down onto the substrate 1 and makes contact, forming an interface 22. At this interface 22, the substrate 1 and the wiring member 3 are in contact only by electrostatic force or intermolecular force, resulting in low adhesion strength. On the other hand, the interface 21 in the area where the thin film 6 remains unetched has relatively high adhesion strength compared to interface 22 because the substrate 1 and the wiring member 3 are in close contact via the thin film 6. In other words, the interface 22 in the area where the thin film 6 was removed by etching corresponds to the second bonding interface 12a, and the interface 21 in the area where the thin film 6 remained unetched corresponds to the first bonding interface 11a. At interface 22, the wiring member 3 has been surface-treated by etching.

[0042] After this treatment, there may be a case where the adhesion strength of the first bonding interface 11 a and the second bonding interface 12 a between the wiring member 3 and the substrate 1 is confirmed. In this case, it is preferable to use a method of measuring the force applied to each bonding interface when peeling occurs in a tensile test, a peel test, a shear test, or the like, or a method of measuring the time until peeling occurs in an operational test such as a heat cycle test.

[0043] Furthermore, a step (S4b) is carried out in which terminals 4 are joined to wiring member 3. Terminals 4 are joined to both ends of wiring member 3 by soldering or the like. The joining method may be ultrasonic joining or the like.

[0044] Finally, a step (S5b) is carried out to seal the wiring member 3 with the sealing member 2. The sealing method may be transfer molding, insert molding, potting or the like.

[0045] Through these steps S1b to S5b, the peel sensor according to the first embodiment is manufactured.

[0046] <Modification 2 of the manufacturing method of the peel-off sensor> Next, a description will be given of Modification 2 of the manufacturing method of the peel-off sensor according to Embodiment 1. In the manufacturing method according to Modification 2, thin film formation and selective etching are performed in a manner different from that of Modification 1.

[0047] 12 is a flowchart of a second modification of the method for manufacturing a peel sensor according to the first embodiment. In the second modification, similar to the first modification, a step (S1c) of forming a thin film 6 on a substrate 1 is first performed. That is, the thin film 6 is formed on the surface of the substrate 1 on which the wiring member 3 is to be formed. The thin film 6 may be any film that improves or reduces the adhesive strength between the substrate 1 and the wiring member 3, such as a nickel (Ni) plating film. In the case of a nickel (Ni) plating film, the adhesiveness is improved by an anchor effect on the substrate 1 and a metallic bond with the wiring member 3. The thin film 6 may be formed by painting, plating, physical vapor deposition (PVD), chemical vapor deposition (CVD), chemical conversion treatment, oxidation treatment, or the like.

[0048] Thereafter, a step (S2c) is performed in which any portion of the formed thin film 6 is selectively etched. If the formation of the thin film 6 improves the adhesion strength between the substrate 1 and the wiring member 3, the portion where the thin film 6 has been selectively etched away will have a relatively lower adhesion strength than the portion where the thin film 6 was formed. In other words, the surface where the thin film 6 has been formed corresponds to the first bonding interface 11a between the wiring member 3 and the substrate 1, and the surface where the thin film 6 has been selectively etched away corresponds to the second bonding interface 12a. Depending on the type of thin film 6, conversely, the surface where the thin film 6 has been formed may correspond to the second bonding interface 12a, and the surface where the thin film 6 has been selectively etched away may correspond to the first bonding interface 11a. In this case, the formation of the thin film 6 may reduce adhesion.

[0049] Next, a step (S3c) is carried out to form wiring member 3 on substrate 1. Wiring member 3 is formed on the surface of substrate 1 on which thin film 6 has been formed and selectively etched in the above-described steps S1c and S2c. The method for forming wiring member 3 on substrate 1 may be electrolytic plating, electroless plating, vacuum deposition, sputtering, or the like.

[0050] After the wiring member 3 is disposed on the substrate 1, the adhesion strength of the first bonding interface 11 a and the second bonding interface 12 a between the wiring member 3 and the substrate 1 may be checked. In this case, it is preferable to use a method of measuring the force applied to each bonding interface when peeling occurs in a tensile test, a peel test, a shear test, or the like, or a method of measuring the time until peeling occurs in an operational test such as a heat cycle test.

[0051] Furthermore, a step (S4c) is carried out in which terminals 4 are joined to wiring member 3. Terminals 4 are joined to both ends of wiring member 3 by soldering or the like. The joining method may be ultrasonic joining or the like.

[0052] Finally, a step (S5c) is carried out to seal the wiring member 3 with the sealing member 2. The sealing method may be transfer molding, insert molding, potting or the like.

[0053] Through these steps S1c to S5c, the peel sensor according to the first embodiment is manufactured.

[0054] Second Embodiment A peel sensor 200 according to a second embodiment will now be described. In the peel sensor 100 according to the first embodiment, one wiring member 3 is disposed on the substrate 1, but in the peel sensor 200 according to the second embodiment, a plurality of wiring members 3 are disposed independently on the substrate 1 without being connected to each other.

[0055] 13 is a plan view of the peel sensor according to the second embodiment. For convenience, the sealing member 2 is shown in a see-through manner with dotted lines. In the peel sensor 200, multiple wiring members 3 are arranged independently on the substrate 1 without being connected to each other, and terminals 4 are connected to both ends of each wiring member 3. The sealing member 2 seals all of the wiring members 3, and each terminal 4 protrudes from the sealing member 2.

[0056] As shown in FIG. 13 , each of the four wiring members 3 has a first portion 31 and a second portion 32. The first portion 31 and the second portion 32 have different adhesion strengths at their bonding interfaces with the substrate 1. Although not shown in FIG. 13 , as in the first embodiment, the bonding interface between the first portion 31 of each wiring member 3 and the substrate 1 is defined as a first bonding interface 11a. Furthermore, the bonding interface between the second portion 32 of each wiring member 3 and the substrate 1 is defined as a second bonding interface 12a. Regarding the adhesion strength between the wiring members 3 and the substrate 1, the adhesion strength of the second bonding interface 12a is lower than the adhesion strength of the first bonding interface 11a. In other words, peeling between the wiring members 3 and the substrate 1 is more likely to occur at the second bonding interface 12a than at the first bonding interface 11a. Therefore, peeling between the substrate 1 and the wiring members 3 first occurs at the second bonding interface 12a. In other words, in the initial stage of peeling, only the second bonding interface 12a is peeled, and the first bonding interface 11a is not peeled. The adhesion strength of the first bonding interfaces 11a of each wiring member 3 may be the same or different. The same applies to the second bonding interfaces 12a of each wiring member 3. Furthermore, at the bonding interface between the substrate 1 and the wiring member 3, bonding interfaces having different adhesion strengths other than the first bonding interface 11a and the second bonding interface 12a may exist. Note that, for convenience, different diagonal patterns are applied to the first portion 31 and the second portion 32 to distinguish them from each other, but the presence or absence of the patterns does not limit the scope of this embodiment. Furthermore, although FIG. 13 shows four wiring members, any number of wiring members may be used as long as it is two or more.

[0057] When the peel sensor 200 is exposed to an environment such as high temperature, high humidity, temperature cycles, or the presence of corrosive substances, peeling may occur at the bonding interface 10 (not shown in FIG. 13 ) between the substrate 1 and the sealing member 2 and at the second bonding interface 12 a (not shown in FIG. 13 ) between the wiring member 3 and the substrate 1, as in the first embodiment. On the other hand, peeling may not occur at the first bonding interface 11 a (not shown in FIG. 13 ) between the wiring member 3 and the substrate 1. This situation occurs because, as described in FIG. 13 , the second bonding interface 12 a has a lower adhesion strength than the first bonding interface 11 a. In this situation, stress is applied between the first portion 31 and the second portion 32 of the wiring member 3, resulting in breakage or deformation of the wiring member 3. This situation is more likely to occur if the bonding interface 10 and the second bonding interface 12 a are adjusted to have similar adhesion strengths.

[0058] When the wiring member 3 is deformed or disconnected in this manner, the electrical characteristics, such as the resistance value of the wiring member 3 itself and the current value and voltage value measured by the peel sensor 200, change. Furthermore, when the wiring member 3 is deformed or disconnected, the substrate 1 and the sealing member 2 are peeled off, as described with reference to FIGS. 4 and 5 . Therefore, peeling between the substrate 1 and the sealing member 2 can be detected based on the change in the electrical characteristics due to the deformation or disconnection of the wiring member 3. Furthermore, as described above, the change in the electrical characteristics of the wiring member 3 is premised on peeling between the substrate 1 and the sealing member 2, and therefore the peel sensor 200 is unlikely to make a false detection when the substrate 1 and the sealing member 2 are not peeled off.

[0059] In the peel sensor 200, the multiple wiring members 3 are arranged independently on the substrate 1 without being connected to one another, so that it is possible to separately measure changes in the electrical characteristics of each wiring member 3. When a change in the electrical characteristics is detected in a specific one of the multiple wiring members 3, it is known that peeling has occurred between the substrate 1 and the sealing member 2 in the vicinity thereof, and therefore it is possible to detect not only the presence or absence of peeling, but also the position of peeling.

[0060] Third Embodiment A peel sensor 300 according to a third embodiment will now be described. In the peel sensor 200 according to the second embodiment, the multiple wiring members 3 are arranged independently on the substrate 1, but in the peel sensor 300 according to the third embodiment, the multiple wiring members 3 are connected to each other and arranged on the substrate 1.

[0061] 14 is a plan view of a peel sensor according to a third embodiment. For convenience, the sealing member 2 is shown in a see-through manner with dotted lines. In the peel sensor 300, multiple wiring members 3 are connected to each other and arranged on a substrate 1, and terminals 4 are connected to both ends of the integrated wiring members 3. Each wiring member 3 has a first portion 31 and a second portion 32 that have different adhesion strengths to the substrate 1, and the first portions 31 and second portions 32 are connected alternately. In addition, the sealing member 2 seals all of the wiring members 3, and the terminals 4 protrude from the sealing member 2.

[0062] As shown in FIG. 14 , each wiring member 3 has a first portion 31 and a second portion 32. The first portion 31 and the second portion 32 have different adhesion strengths at their bonding interfaces with the substrate 1. Although not shown in FIG. 14 , similar to the case of FIG. 3 in the first embodiment, the bonding interface between the first portion 31 of each wiring member 3 and the substrate 1 is defined as a first bonding interface 11a. Furthermore, the bonding interface between the second portion 32 of each wiring member 3 and the substrate 1 is defined as a second bonding interface 12a. Regarding the adhesion strength between the wiring member 3 and the substrate 1, the adhesion strength of the second bonding interface 12a is lower than the adhesion strength of the first bonding interface 11a. In other words, peeling between the wiring member 3 and the substrate 1 is more likely to occur at the second bonding interface 12a than at the first bonding interface 11a. Therefore, peeling between the substrate 1 and the wiring member 3 first occurs at the second bonding interface 12a. In other words, in the initial stage of peeling, only the second bonding interface 12a is peeled, and the first bonding interface 11a is not peeled. The adhesion strength of the first bonding interface 11a of each wiring member 3 may be the same or different. The same applies to the second bonding interface 12a of each wiring member 3. Furthermore, at the bonding interface between the substrate 1 and the wiring member 3, bonding interfaces having different adhesion strengths other than the first bonding interface 11a and the second bonding interface 12a may exist. Note that, for convenience, different diagonal patterns are applied to the first portion 31 and the second portion 32 to distinguish them from each other in the description, but the presence or absence of the patterns does not limit the scope of this embodiment. Furthermore, the number of wiring members may be any number equal to or greater than two.

[0063] When the peel sensor 300 is exposed to an environment such as high temperature, high humidity, temperature cycles, or the presence of corrosive substances, peeling may occur at the bonding interface 10 (not shown in FIG. 14 ) between the substrate 1 and the sealing member 2 and at the second bonding interface 12 a (not shown in FIG. 14 ) between the wiring member 3 and the substrate 1, as in the first embodiment. On the other hand, peeling may not occur at the first bonding interface 11 a (not shown in FIG. 14 ) between the wiring member 3 and the substrate 1. This situation occurs because, as described in FIG. 14 , the second bonding interface 12 a has a lower adhesion strength than the first bonding interface 11 a. In this situation, stress is applied between the first portion 31 and the second portion 32 of the wiring member 3, resulting in breakage or deformation of the wiring member 3. This situation is more likely to occur if the bonding interface 10 and the second bonding interface 12 a are adjusted to have similar adhesion strengths.

[0064] When the wiring member 3 is deformed or disconnected in this manner, the electrical characteristics, such as the resistance value of the wiring member 3 itself and the current value and voltage value measured by the peel sensor 300, change. Furthermore, when the wiring member 3 is deformed or disconnected, the substrate 1 and the sealing member 2 are peeled off, as described with reference to FIGS. 4 and 5 . Therefore, peeling between the substrate 1 and the sealing member 2 can be detected based on the change in the electrical characteristics due to the deformation or disconnection of the wiring member 3. Furthermore, as described above, the change in the electrical characteristics of the wiring member 3 is premised on peeling between the substrate 1 and the sealing member 2, and therefore the peel sensor 300 is unlikely to make a false detection when the substrate 1 and the sealing member 2 are not peeled off.

[0065] In the peel sensor 300, multiple wiring members 3 are connected to each other, and terminals 4 are connected only to both ends of the integrated wiring members, so that peeling between the substrate 1 and the sealing member 2 can be detected over a wide area with fewer terminals than the peel sensor 200 of embodiment 2.

[0066] The shape of the wiring member in which multiple wiring members 3 are integrated as shown in FIG. 14 is an example, and may be, for example, an annular shape, and may be selected arbitrarily. Furthermore, there may be two or more integrated wiring members, and in that case, their positions on the substrate 1 may be selected arbitrarily, and they may be parallel, or one may be contained within the other. In this case, the adhesion strength between the substrate 1 and each integrated wiring member does not have to be the same. Furthermore, in the peel sensor 300, two or more peel sensors 100 according to the first embodiment may be connected in series to form an integrated wiring member. In this case, the specifications of each peel sensor (such as the adhesion strength between the wiring members and surrounding members) do not have to be the same.

[0067] Fourth Embodiment A peel sensor 400 according to a fourth embodiment will now be described. In the peel sensor 400, wiring members 3a to 3e having different electrical characteristics are arranged on a substrate 1.

[0068] 15 is a plan view of a peel sensor according to a fourth embodiment. For convenience, the sealing member 2 is shown in a see-through manner with a dotted line. In the peel sensor 400, wiring members 3a, 3b, 3c, 3d, and 3e are connected to form a closed circuit 33 and arranged on a substrate 1, and a terminal 4 is connected to one end of each of the wiring members 3a and 3c. The closed circuit 33 is a circuit in which, even if one of the multiple wiring members connecting the terminals is disconnected, a current path between the terminals is ensured by the remaining wiring members. The sealing member 2 seals all of the wiring members 3a to 3e, and the terminal 4 protrudes from the sealing member 2.

[0069] 15 , the wiring member 3a has a plurality of first portions 31a and a plurality of second portions 32a. The first portions 31a and the second portions 32a have mutually different adhesion strengths at the bonding interface with the substrate 1. Similarly, the wiring members 3b to 3e also have first portions 31b to 31e and second portions 32b to 32e, respectively, and the respective first portions and second portions have mutually different adhesion strengths at the bonding interface with the substrate 1.

[0070] The first portions 31a to 31e of the wiring member each have a first bonding interface (each corresponding to 11a in FIG. 3) with the substrate 1. The second portions 32a to 32e of the wiring member each have a second bonding interface (each corresponding to 12a in FIG. 3) with the substrate 1.

[0071] In the wiring member 3a, the adhesion strength of the second bonding interface (corresponding to 12a in FIG. 3 ) of the second portion 32a is lower than the adhesion strength of the first bonding interface (corresponding to 11a in FIG. 3 ) of the first portion 31a. That is, peeling between the wiring member 3a and the substrate 1 is more likely to occur at the second bonding interface than at the first bonding interface. For this reason, peeling between the substrate 1 and the wiring member 3a first occurs at the second bonding interface. That is, in the early stage of peeling in the wiring member 3a, only the second bonding interface is peeled, and the first bonding interface is not peeled.

[0072] The relationship between the adhesion strength of the first and second bonding interfaces in the wiring members 3b to 3e is the same as that in the case of the wiring member 3a. Note that, at the bonding interfaces between the substrate 1 and the wiring members 3a to 3e, bonding interfaces having different adhesion strengths other than the first and second bonding interfaces may exist.

[0073] When the peel sensor 400 is exposed to an environment such as high temperature, high humidity, temperature cycles, or the presence of corrosive substances, peeling may occur at either the bond interface 10 between the substrate 1 and the sealing member 2 or the second bond interface between the wiring members 3a-3e and the substrate 1 (each corresponding to 12a in FIG. 3 ), as in the first embodiment. On the other hand, peeling may not occur at the first bond interface between the wiring members 3a-3e and the substrate 1 (each corresponding to 11a in FIG. 3 ). This situation occurs because, as described in FIG. 15 , the second bond interface in the wiring members 3a-3e has a lower adhesion strength than the first bond interface. In this situation, stress is applied between the first portion (31a-31e) of the wiring member and the corresponding second portion (32a-32e) of the wiring member, resulting in breakage or deformation of the wiring member. Note that this situation is more likely to occur if the bond interface 10 and the second bond interface are adjusted to have similar adhesion strengths.

[0074] When any of the wiring members 3a to 3e is deformed or disconnected in this way, the electrical characteristics, such as the resistance value of the wiring member and the current value and voltage value measured by the peel sensor 400, change. Furthermore, when any of the wiring members 3a to 3e is deformed or disconnected, the substrate 1 and the sealing member 2 are peeled off, as described with reference to FIGS. 4 and 5 . Therefore, peeling between the substrate 1 and the sealing member 2 can be detected based on the change in the electrical characteristics due to the deformation or disconnection of any of the wiring members 3a to 3e. Furthermore, as described above, the change in the electrical characteristics of the wiring members 3a to 3e is premised on the peeling between the substrate 1 and the sealing member 2, and therefore the peel sensor 400 is unlikely to make a false detection when the substrate 1 and the sealing member 2 are not peeled off.

[0075] If any of the wiring members 3a to 3e that make up the closed circuit 33 breaks, the electrical characteristics of the closed circuit 33 change, and the measured value of this changes the wiring member that has broken. For example, if the wiring member 3a breaks, the current path in the closed circuit 33 becomes the wiring members 3b, 3c, 3d, and 3e, and the electrical characteristics of the closed circuit 33 become a composite electrical characteristic of these. The broken wiring member can be identified based on the value of this composite electrical characteristic. Here, it is desirable that the wiring members 3a to 3e all have different electrical characteristics. This is because if there are multiple wiring members with the same electrical characteristics, it becomes impossible to identify the location of the break.

[0076] The shape of the closed circuit 33 shown in FIG. 15 is an example, and may be, for example, an annular shape, and may be selected arbitrarily. Two or more closed circuits 33 may be arranged on the substrate 1, and in this case, their positions may be selected arbitrarily, and they may be arranged in parallel, or one may be contained within the other. In this case, the adhesive strength between each closed circuit 33 and the substrate 1 may not be the same. Furthermore, in the peel sensor 400, two or more peel sensors 100 according to the first embodiment may be connected in series to form a closed circuit. In this case, the specifications of each peel sensor (such as the adhesive strength between the wiring members and the surrounding members) may not be the same.

[0077] Fifth Embodiment An electronic device according to a fifth embodiment will now be described. The electronic device includes a peel sensor (100, 200, 300, 400) according to the present disclosure.

[0078] FIG. 16 is a conceptual diagram illustrating an example of an electronic device 800 equipped with a peel sensor (100, 200, 300, 400) according to the present disclosure. The electronic device 800 is not particularly limited in type. The electronic device 800 is installed in, for example, factory automation (FA) equipment such as inverters, servo motors, and sequencers, as well as elevators, generators, automobiles, and railways. Corrosive substances may be present in the environment in which these various applications are used. To prevent deterioration due to water vapor and corrosive substances present in such environments, electronic devices may encapsulate structures such as wiring members 3 and semiconductors with a sealing member 2 made of resin or other material. However, if the sealing member 2 and substrate 1 peel during use, water and corrosive substances may penetrate, degrading the internal structures and resulting in failures shorter than expected. Therefore, it is necessary to detect peeling between the sealing member 2 and substrate 1.

[0079] The electronic device 800 includes an electronic component 500, peel sensors (100, 200, 300, 400), a measuring device 600, and an alarm device 700. The peel sensors (100, 200, 300, 400) are used to estimate the presence or absence of peeling of the electronic component 500 and the degree of progress of the peeling. While FIG. 16 shows one each of the peel sensors (100, 200, 300, 400), the measuring device 600, and the alarm device 700, multiple peel sensors may be provided. These components may be located either inside or outside the electronic device 800, or may be mounted inside the electronic component 500. The measuring device 600 measures electrical characteristics such as the electrical resistance, current, and voltage of the peel sensors (100, 200, 300, 400). The measuring device 600 is, for example, an ohmmeter, an ammeter, or a voltmeter, and detects peeling based on changes in the measured resistance, current, voltage, etc. In this case, the measuring device 600 may include not only measuring instruments (detecting instruments) such as an ohmmeter, ammeter, and voltmeter, but also a power source for supplying electricity (power) required for measurement.

[0080] The measuring device 600 includes, for example, a microprocessor, and controls the notification device 700 to notify the user when the electrical characteristics of the peel sensors (100, 200, 300, 400) exceed a predetermined threshold. It is desirable to determine this threshold from the results of measuring in advance the change in the electrical characteristics that occurs when peeling occurs in the peel sensors (100, 200, 300, 400). The notification device 700 includes, for example, a liquid crystal display or an LED (Light Emitting Diode) indicator, and notifies the user that the electrical characteristics measured by the measuring device 600 exceed the threshold.

[0081] REFERENCE SIGNS LIST 1 substrate, 2 sealing member, 3 wiring member, 4 terminal, 5 masking member, 6 thin film, 11a first bonding interface, 12a second bonding interface, 31 first portion, 32 second portion, 33 closed circuit 100, 200, 300, 400 peeling sensor, 500 electronic component, 600 measuring device, 700 alarm device, 800 electronic device.

Claims

1. A peeling sensor comprising a substrate, a wiring member disposed on the substrate, and a sealing member for sealing the wiring member, wherein a bonding interface between the substrate and the wiring member has a first bonding interface and a second bonding interface, and the adhesion strength between the substrate and the wiring member at the second bonding interface is lower than that at the first bonding interface.

2. The peeling sensor according to claim 1, wherein peeling between the sealing member and the wiring member is detected by a change in an electrical characteristic of the wiring member that occurs when the substrate and the wiring member peel at the second bonding interface.

3. The peeling sensor according to claim 1 or 2, wherein the adhesion strength of the bonding interface at the second bonding interface between the substrate and the wiring member is smaller than the adhesion strength of the bonding interface between the wiring member and the sealing member.

4. The peeling sensor according to any one of claims 1 to 3, wherein the adhesion strength of the bonding interface at the first bonding interface between the substrate and the wiring member is higher than the adhesion strength of the bonding interface between the wiring member and the sealing member.

5. The peeling sensor according to claim 2, wherein a plurality of the wiring members are disposed on the substrate, and each of the wiring members is not connected to each other and separately measures a change in an electrical characteristic.

6. The peeling sensor according to claim 2, wherein a plurality of the wiring members are disposed on the substrate, and the plurality of wiring members are connected to each other and measure a change in an electrical characteristic as a whole.

7. The peeling sensor according to claim 6, wherein some or all of the plurality of wiring members have different electrical characteristics, and the plurality of wiring members form a closed circuit.

8. The peeling sensor according to any one of claims 2, 5, 6, or 7, wherein the change in the electrical characteristic occurs due to disconnection or deformation of the wiring member when the substrate 1 and the wiring member peel at the bonding interface of the second bonding interface.

9. A method for manufacturing a peeling sensor, comprising a step of forming a wiring member on a substrate and a step of sealing the wiring member with a sealing member, wherein a bonding interface between the substrate and the wiring member has a first bonding interface and a second bonding interface with different adhesion strengths between the substrate and the wiring member, and the adhesion strength between the substrate and the wiring member at the second bonding interface is lower than that at the first bonding interface.

10. The method for manufacturing a peeling sensor according to claim 9, wherein at the bonding interface between the substrate and the wiring member, a surface treatment for controlling the adhesion strength between the substrate and the wiring member is performed on either or both of the first bonding interface and the second bonding interface.

11. The method for manufacturing a peeling sensor according to claim 9, further comprising a step of forming a thin film on the substrate before the step of forming a wiring member on the substrate, and a step of selectively etching the thin film to form the second bonding interface.

12. An electronic device comprising the peeling sensor according to any one of claims 1 to 8.

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