Capacitor and manufacturing method thereof

Abstract

The present invention provides a capacitor (1) comprising a body element (10) on which a dielectric layer (13) made of a thermosetting resin and a metal electrode layer (11) are laminated or wound, and an external electrode (20) to which at least a portion of the body element is connected. A boundary region (30) that includes a dense metallikon region (21) that is made of aluminum or an alloy containing aluminum and that contacts at least the dielectric layer made of a thermosetting resin and the metal electrode layer has a void rate VR expressed as follows: 0<VR≤11%

Description

[Technical Field]

[0001] The present invention relates to a capacitor and a method for manufacturing the same. [Background technology]

[0002] The thin-film polymer laminate capacitor described in Japanese Patent Application Publication No. 2021-19133 has a chip-shaped laminate formed by alternately stacking and bonding dielectric layers and internal electrode layers including a first metal layer formed by vapor-depositing a first metal on the dielectric layer and a second metal layer formed by vapor-depositing a second metal on the first metal layer, and external electrodes formed on one end and the other end of the laminate, wherein the laminate has a first region in which the first metal is formed on the dielectric layer and alternately stacked, and an edge region in which a second metal layer is formed on the layer connected to the one end of the first metal layer and the layer connected to the other end of the first metal layer and alternately stacked, wherein the first region has a capacitor functional region and the edge region has a heavy edge formed. DISCLOSURE OF THE INVENTION

[0003] An example of a thin film polymer multilayer capacitor (hereinafter referred to as PML) includes a body (capacitor body, capacitor element) made of a laminate of metal electrode layers deposited with aluminum and a dielectric layer made of a highly heat-resistant thermosetting resin, such as an acrylic resin or a methacrylic resin (e.g., tricyclodecane dimethanol dimethacrylate or tricyclodecane dimethanol diacrylate). The PML also has external electrodes connected to the ends of the body, and the connection between the external electrodes and the body includes a layer (metallikon layer) formed by spraying (thermal spraying, metallikon) molten metal. In conventional film capacitors, where the body is manufactured by winding a dielectric layer and an electrode layer, an external electrode including a metallikon layer is provided to connect the body to an external circuit.

[0004] Various metals or alloys can be used as the metallikon metal that forms the metallikon layer, but because molten metal is sprayed onto the main body, deterioration of the resin-based dielectric layer can be a problem. One example of a metallikon metal is brass (Cu + Zn), which has a high melting point and is easy to reflow, and is also easy to plate as the exterior of the external electrodes. However, the metallikon layer is formed with a sufficient distance (spraying distance) to avoid or reduce any effects on the dielectric layer. Another example of a metallikon metal is zinc, which has a low melting point and is therefore effective in suppressing thermal degradation during spraying.

[0005] Another example of a metallikon metal is aluminum, which has excellent adhesion to the electrode layer inside the main body and good moisture resistance. However, when aluminum is used as a metallikon metal, alloying is performed to lower the melting point, but there are no reports on the conditions that contribute to improving performance as evaluated by ESR (equivalent series resistance), loss (tanδ), etc.

[0006] In recent years, there has been a demand for capacitors with even higher withstand voltages and lower ESR. To increase withstand voltage, the electrode layer of the main body (capacitor element) is made thinner so that its surface resistivity (sheet resistivity) is sufficiently high, which also means that the connection parts become thinner. For this reason, there is a demand for capacitors with even lower connection resistance at the connection parts and sufficiently small ESR.

[0007] One aspect of the present invention is a capacitor having a main body in which a thermosetting resin dielectric layer and a metal electrode layer are laminated or wound, and an external electrode to which at least a portion of the main body is connected. The external electrode includes a metallikon region made of aluminum or an aluminum-containing alloy, and the porosity VR of the metallikon region at least in the boundary region in contact with the thermosetting resin dielectric layer and the metal electrode layer satisfies the following condition (1): 0 <VR≦11% ···(1)

[0008] In the past, when manufacturing capacitors, typically film capacitors, where external electrodes are formed using metallikon (thermal spraying), concerns about thermal degradation of the dielectric layer have been raised. For this reason, when forming a metallikon region, efforts have been made to suppress increases in resistance due to thermal degradation, particularly at the connection (boundary) between the main body and the metallikon region, by controlling the spraying temperature below a certain level and maintaining a certain spray distance. In contrast, the inventors of the present application have discovered that for a main body using a dielectric layer made of a thermosetting resin, rather than concerns about thermal degradation of the dielectric layer, capacitor performance evaluated by ESR can be improved by improving the density (compactness, denseness) of the metallikon region on the metallikon side, particularly in the boundary region where it contacts the dielectric layer and electrode layer. In other words, contrary to conventional methods, they found that by increasing the temperature at which metal is sprayed to form the boundary region of the metallikon region and shortening the spraying distance, the density of the metallikon region can be improved, resulting in improved capacitor performance. Furthermore, the inventors of the present application have found that the density of the metallikon region can be evaluated, for example, by the porosity VR of the metallikon region. The upper limit of condition (1) may be 8%.

[0009] In other words, in the past, when forming (manufacturing) external electrodes using metallikon, deterioration of performance was prevented by suppressing the temperature rise in the main body. However, the inventors of the present application have discovered that, in a capacitor having a dielectric layer made of thermosetting resin, when aluminum or its alloy is used as the metallikon metal, the performance indicated by ESR is improved by increasing the temperature of the boundary region (connection region) between the main body and the metallikon region.

[0010] Another aspect of the present invention is a method for manufacturing a capacitor, comprising: manufacturing a body in which a thermosetting resin dielectric layer and a metal electrode layer are laminated or wound; and forming an external electrode connected to at least a portion of the body, wherein forming the external electrode includes forming a metallikon region by thermal spraying aluminum or an aluminum-containing alloy so as to be in contact with the body, and further including maintaining a temperature (surface temperature) of at least 150°C when forming a boundary region of the metallikon region in contact with at least the thermosetting resin dielectric layer and the metal electrode layer. The temperature of the boundary region may be maintained at 180°C or higher.

[0011] The conditions for forming the metallikon region may be controlled by the spraying distance instead of or in addition to the temperature of the boundary region. That is, another aspect of the present invention is a method for manufacturing a capacitor, including manufacturing a body portion in which a thermosetting resin dielectric layer and a metal electrode layer are laminated or wound, and forming an external electrode connected to at least a portion of the body portion, wherein forming the external electrode includes spraying aluminum or an aluminum-containing alloy to form a metallikon region so as to contact the body portion, and further includes maintaining the spraying distance for forming the boundary region of the metallikon region in contact with at least the thermosetting resin dielectric layer and the metal electrode layer to a maximum of 200 mm. The spraying distance may be 150 mm or less. These conditions are important for providing a capacitor that satisfies the above-mentioned condition (1).

[0012] The capacitor according to the present invention may have a metallikon region connected to the main body portion, the metallikon region containing at least 80% aluminum. This provides a capacitor with good connectivity with the electrode layer of the main body portion and low resistance. The metallikon region may be 100% aluminum, or may contain other components such as silicon within a range that satisfies the above requirements. The metallic electrode layer of the main body portion may be made of aluminum or an alloy containing aluminum, which can suppress peeling and deformation caused by dissimilar metals.

[0013] The thermosetting resin dielectric layer may contain at least one of an acrylic resin and a methacrylic resin. The thermosetting resin dielectric layer may have a thickness of 1.5 μm or less (maximum 1.5 μm). Furthermore, the external electrode may include an outer metallikon region provided in contact with the outside of the inner metallikon region that contacts the main body, the outer metallikon region being made of a metal or alloy different from that of the inner metallikon region. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing an overview of a capacitor. [Figure 2] 1 is a flowchart showing a manufacturing process of a capacitor. [Figure 3] FIG. 10 shows the evaluation results of Examples and Reference Examples. [Figure 4] FIG. 1 is a diagram showing the configuration of a metallicon. [Figure 5] A diagram showing porosity. MODE FOR CARRYING OUT THE INVENTION

[0015] FIG. 1 shows an example of a capacitor according to the present invention. The capacitor 1, the external appearance of which is shown in FIG. 1(a), is an example of a thin-film polymer multilayer capacitor (hereinafter referred to as PML). It has a main body (main body, laminate, capacitor element) 10, which is formed by laminating a dielectric layer 13 and an electrode layer 11 together, and an external electrode 20 connected to the main body 10. As shown in the cross-sectional view of FIG. 1(b), the main body 10 includes an active layer 7 that exhibits capacitance and is located at the center of the thickness direction, dummy layers 8 that do not exhibit capacitance and are located above and below the active layer 7, and protective layers 9 that are located above and below the active layer 7 and dummy layer 8. The active layer 7 and dummy layer 8 are configured by laminating a resin layer (dielectric layer) 13 and an electrode layer 11, and the protective layer 9 is composed only of resin. The external electrode 20 is formed to bond to the electrode layer 11 and the resin layer 13 of the active layer 7 and dummy layer 8, and includes an internal metallikon layer 25, a copper-plated layer 27 that covers the periphery thereof, and a tin-plated layer 28 that further covers the outside.

[0016] The metallikon layer 25 includes an inner region (inner layer, first metallikon region) 21 that contacts the dielectric layer 13 and electrode layer 11 of the main body 10, and an outer region (outer layer, second metallikon region) 22 provided outside the inner region. The first metallikon region 21 includes a boundary region 30 where a metallikon metal (first metallikon metal) is thermally sprayed at the cut boundary surface 15 of the main body 10. In this example, the first metallikon metal is aluminum or an aluminum-based alloy, and the first metallikon region 21 includes a boundary region 30 made of aluminum or an alloy containing aluminum that contacts the main body 10. The entire metallikon layer 25 may be formed of the same metal, for example, aluminum. Alternatively, the inner first metallikon region 21 may be formed using a material and / or method that prioritizes connection performance with the main body 10, and the outer second metallikon region 22 may be formed using a material and / or method that prioritizes external connection performance. The second metallikon region 22 may be formed from a material that has high adhesion to the outer plating layer 27 and high heat resistance during reflow, such as brass. The second metallikon region 22 may also be made of copper, tin, zinc, or an alloy containing any of these.

[0017] An example of a manufacturing method for PML1 is shown in Figure 2. An example of the specifications for PML1 is as follows: Rated voltage: 63V Capacity: 2.2μF Capacitor size: 5.7 x 5.0 x 1.73 mm (W x D x H) Thickness of electrode layer 11: 15 nm Material of electrode layer 11: aluminum (Al) Thickness of dielectric layer 13: 0.6 μm Material of dielectric layer 13: thermosetting resin (methacrylic resin) (Example: Tricyclodecane dimethanol dimethacrylate) Vapor deposition resistance: 12~13Ω / □ Thickness of the first metallikon region 21: 60 to 80 μm Material of the first metallikon region 21: aluminum (Al99.99%) or Aluminum silicon alloy (Al88%+Si12%) Thickness of the second metallikon region 22: 120 to 140 μm Material of the second metallicon region 22: Brass (Cu 65% + Zn 35%)

[0018] In the manufacturing method 40 shown in FIG. 2 , a laminate that serves as the base of the main body (main body portion) 10 is manufactured in step 41. One example of a method for manufacturing a laminate is to form each layer by vapor deposition. A known apparatus manufactures the laminate that serves as the base of the main body portion 10 by vapor deposition of a dielectric layer 13 and an electrode layer 11 on a rotating drum in a reduced-pressure environment (vacuum environment) in a vacuum chamber. The laminate may also be manufactured using other methods, such as coating or printing. In this example, the thermosetting resin applied as the dielectric layer 13 is cured using an electron beam irradiation device or the like to form the dielectric layer 13. Furthermore, the surface of the dielectric layer 13 is plasma-treated in a plasma processing device for the next process. Before forming the electrode layer 11, a patterning unit may apply an oil margin to the dielectric layer 13 to pattern the electrode layer 11. When using a pre-fabricated material such as a film as the dielectric layer, as in a film capacitor, the dielectric layer formation process may be omitted, or may be performed separately from the electrode layer formation process.

[0019] In step 42, the laminate is cut into strips to form the main body 10 in a strip state (stick state). The main body 10 in a strip state may be formed directly from the laminate, or the main body 10 in a strip state may be manufactured by performing other processes such as flattening press processing and card cutting processing. In step 43, the cut strip surface is subjected to plasma ashing to form the connection portion (connection surface) 15 with the external electrode 20. As an example, plasma ashing may be performed using a mixed gas of oxygen and carbon tetrafluoride to form the connection portion 15 between the metallikon and the internal electrode. Plasma ashing burns off the dielectric on the cut surface of the strip, exposing the internal electrode (electrode layer) 11.

[0020] In step 44, an external electrode 20 is formed on the plasma-ashed connecting surface 15 by metallikon (metal spraying). In this example, as described above, Al or an Al-based alloy (e.g., Al+Si) is sprayed onto the connecting surface 15 as a first metallikon metal to form a first metallikon region (metallikon layer) 21. In an early stage 44a of this process, a boundary region 30 is formed that contacts the thermosetting resin dielectric layer 13 and the metallic electrode layer 11 that appear on the connecting surface 15. Thereafter, brass is sprayed as a second metallikon metal to form a second metallikon region (second metallikon layer) 22.

[0021] In step 45, a copper plating layer 27 and a tin plating layer 28 are formed in this order by electrolytic plating or the like. The tin plating layer 28 is effective in improving the solder wettability of the external electrodes 20. Thereafter, required processing of the external electrodes 20, such as heat treatment, is performed. Furthermore, in step 46, the strip-like body portion 10 on which the external electrodes 20 have been formed is cut into chips together with the external electrodes 20, thereby manufacturing a PML 1 in which the external electrodes 20 are connected to the body portion 10. Note that the steps shown in FIG. 2 are representative processing steps, and other processing steps may also be performed.

[0022] Figure 3 shows the results of evaluating the performance of several samples manufactured in step 44 by changing the spraying conditions for the metallikon region, particularly the first metallikon region 21, based on the measured ESR. Samples E1-1 to E1-7 have the first metallikon region 21 formed of aluminum (hereinafter referred to as Al, (Al 99.99%)) with the spraying distance SD varied in the range of 50 to 300 mm. Samples E2-1 to E2-7 have the first metallikon region 21 formed of an aluminum silicon alloy (hereinafter referred to as Al + Si (Al 88% + Si 12%)) with the spraying distance SD varied in the range of 50 to 300 mm. Other specifications are as described above.

[0023] As examples of dielectric layers made of thermoplastic resin, the performance of samples R1-1-2 and R2-1-3, in which the external electrodes of the film capacitor were made of Al or Al+Si under the same conditions as above, was evaluated. The performance of sample R3, in which the external electrodes 20 of PML1 were made of brass metallicon, and sample R4, in which the external electrodes of the film capacitor were made of a two-layer metallicon consisting of a zinc-aluminum alloy (hereinafter referred to as Zn+Al, (Zn95%+Al5%)) and a tin-zinc alloy (hereinafter referred to as Sn+Zn, (Sn80%+Zn20%)), was evaluated. The specifications of the film capacitors used in the evaluation are as follows: Rated voltage: 630V Capacity: 10μF Capacitor size: 22.5 x 10.5 x 17.0 mm (W x D x H) Electrode layer thickness: 25 nm Electrode layer material: Aluminum (Al) Dielectric layer thickness: 5 μm Dielectric layer material: Thermoplastic resin (polypropylene) Vapor deposition resistance: 3Ω / □ Thickness of the first metallikon region: 60 to 80 μm Material of the first metallicon region: Aluminum (Al99.99%) or Aluminum silicon alloy (Al88%+Si12%) Thickness of the second metallikon region: 120 to 140 μm Material of the second metallicon region: Brass (Cu 65% + Zn 35%)

[0024] The specifications of the metallikon layer for each sample are summarized in Figure 4. The spraying conditions for each sample are as follows: Spraying method: Wire electric arc spraying Air pressure: 0.39~0.47MPa Thermal spray material: Wire rod with a diameter of 1.2 mm. The components of each wire rod are as follows: Al: (Al 99.99%) Al+Si: (Al88%+Si12%) Brass: (Cu65%+Zn35%) Zn+Al: (Zn95%+Al5%) Sn+Zn: (Sn 80%+Zn 20%)

[0025] The surface temperature ST shown in Figure 3 indicates the temperature of the surface 15 where the sprayed metal comes into contact (sprayed contact surface, connection surface, boundary surface), and is a value representative of the temperature of the boundary region 30 when the sprayed metal forms the metallikon region 21. The temperature of the boundary surface 15 is a value measured by a thermocouple attached to the boundary surface 15. The porosity VR indicates a value obtained by cutting the external electrode 20 including the main body 10 and observing the cross section with a digital microscope (for example, a VHX-5000 manufactured by Keyence Corporation) after PML 1 is manufactured including the external electrode 20 by forming metallikon regions 21 and 22 by spraying metal under the specified conditions described above.

[0026] An example of an observed image is shown in Figure 5. In this example, the observation magnification was 1000x, and voids 23 with a representative length of 0.15 μm or more were detected. The porosity VR (%) was calculated using the following formula (2), and the average value of values ​​observed at least three points on the cross section is shown in Figure 3. Porosity VR (%) = (total void area / total observation area) × 100 (2)

[0027] The ESR shown in Figure 3 is the value measured after the PML was completed as a capacitor. The same applies to film capacitors. The evaluation based on the measured ESR (at 100 kHz) results was set as follows for PML1 and the film capacitor, based on the measured ESR values ​​of commercially available samples R3 and R4. Assessment of PML1 ◎:ESR<20mΩ ○:20≦ESR<30mΩ △:30≦ESR<33mΩ ×:33mΩ≦ESR Film capacitor evaluation ◎:ESR<10mΩ ○:10≦ESR<15mΩ △:15≦ESR<30mΩ ×:30mΩ≦ESR

[0028] As shown in Figure 3, in film capacitor type samples R1-1 to R1-2 and R2-1 to R2-3 in which a thermoplastic resin is used for the dielectric layer 13, when the spraying distance SD is shortened and the temperature of the boundary surface 15 increases, the porosity VR of the Al or Al+Si metallikon region 21, including the boundary region 30 in contact with the boundary surface 15, decreases and the density improves. However, it can be seen that the ESR value increases and the performance as a capacitor deteriorates.

[0029] On the other hand, in PML type samples E1-1 to E2-1 to E2-7, in which a thermosetting resin is used for dielectric layer 13, when the spraying distance SD is shortened and metallikon region 21 is formed including boundary region 30 so that the temperature of boundary surface 15 increases, the porosity VR of Al or Al+Si metallikon region 21, including boundary region 30 in contact with boundary surface 15, decreases, improving density. At the same time, the ESR value decreases, lowering resistance and improving performance as a capacitor.

[0030] 3, it can be seen that in capacitors (Samples E1-1 to E2-1 to E2-7) including dielectric layer 13 made of thermosetting resin (formed or manufactured using thermosetting resin) and metal electrode layer 11, the tendency for capacitor performance, particularly performance related to connection characteristics, to improve is reversed compared to capacitors (Samples R1-1 to R1-2, R2-1 to R2-3) having a thermoplastic resin dielectric layer, depending on the formation method or characteristics of metallikon region 21. In samples having a thermosetting resin dielectric layer, focusing on the porosity VR of metallikon region 21 on the inside that contacts main body 10, it can be seen that when metallikon region 21, including boundary region 30 that contacts thermosetting resin dielectric layer 13 and connection surface 15 where metallikon layer 11 appears, is made of Al or Al+Si, a capacitor with low resistance and low loss can be obtained when the porosity VR is 11% or less. Furthermore, if the porosity VR is 8% or less, the ESR value decreases further, and it is clear that a capacitor with extremely low loss and excellent performance can be provided. On the other hand, in the sample with a thermoplastic resin dielectric layer, even if a metallikon region 21 using Al or Al+Si is formed under the same conditions, good overall performance cannot be obtained. In particular, performance tends to deteriorate as the porosity VR decreases, and when the porosity VR is about 14% or less, the resistance is too high, making it difficult to use a metallikon made of Al or Al+Si.

[0031] Focusing on the parameters for manufacturing the capacitor, it can be seen that for PML1, a low-resistance, low-loss capacitor can be provided by spraying Al or Al+Si to form the metallikon region 21 at a spraying distance SD of 200 mm or less, including the boundary region 30 where the thermosetting resin dielectric layer 13 and the metal electrode layer 11 meet at the connection surface 15. It can be seen that even higher-quality capacitors can be provided if the spraying distance SD is 150 mm or less. Focusing on the temperature ST of the surface (boundary surface) 15 of the spraying target, it can be seen that a low-resistance, low-loss capacitor can be provided by spraying Al or Al+Si to form the metallikon region 21 so that the surface temperature ST, which is the temperature at which the boundary region 30 is formed, is 150°C or higher. It can be seen that even higher-quality capacitors can be provided if the surface temperature ST is 180°C or higher.

[0032] These results suggest that by forming the dielectric layer 13 of the main body 10 from a thermosetting resin and providing the external electrode 20 with a dense metallikon region, it is possible to provide a capacitor 1 using Al or an Al-based alloy as the metallikon metal. In particular, the above disclosure discloses that a capacitor with excellent characteristics can be provided by forming the metallikon region 21 using an Al element or an alloy containing 80% or more Al as the metallikon metal. Therefore, a capacitor satisfying the above conditions and its manufacturing method can provide a capacitor 1 that takes advantage of the properties of aluminum, has excellent adhesion to the electrode layer 11 inside the main body, low resistance and low loss, and also has good moisture resistance. Corrosion caused by dissimilar metals can also be expected to be suppressed. While the above example shows an Al+Si alloy as the Al-based alloy, it is expected that similar characteristics can be obtained with Al-based alloys containing other components.

[0033] In particular, if the metal electrode layer 11 of the main body 10 is made of aluminum or an aluminum-containing alloy, spraying Al or an Al-based alloy onto the boundary surface 15 to form a metallikon region 21 including the boundary region 30 results in the electrode layer 11 of the main body 10 and the metallikon region 21 of the external electrode 20 having the same or similar composition, resulting in a capacitor 1 with high durability and excellent connection performance, with little risk of peeling. While tricyclodecane dimethanol dimethacrylate, an example of a methacrylic resin, is used as the thermosetting resin forming the dielectric layer 13 in the above example, other methacrylic resins may be used. Furthermore, the thermosetting resin may be an acrylic resin, such as tricyclodecane dimethanol diacrylate. It is also possible to assume that other thermosetting resins that can be used as dielectric layers will exhibit similar properties. The thickness of the thermosetting resin dielectric layer 13 is not particularly limited, but may be 1.5 μm or less (maximum 1.5 μm) considering the ability to control a uniform film thickness by vapor deposition.

[0034] Furthermore, in the above example, in addition to the inner metallikon region 21 made of Al or Al+Si, which includes the boundary region 30 in contact with the boundary surface 15, a second outer metallikon region 22 made of brass is provided. The external electrode 20 may be formed of a single metallikon region, or may be formed of three or more layers of metallikon regions. A capacitor 1 including a brass metallikon region 22 has a high melting temperature and a high affinity with the plating layer covering the external electrode 20, making it a suitable example as a surface-mounted device (SMD) that can be attached by reflow or the like.

[0035] As explained above, the use of aluminum or an aluminum-based alloy for the metallikon of the inner layer (first layer, inner side) of a film capacitor, including the boundary region 30 that serves as the electrode lead, has been proposed as a promising approach for improving connectivity and moisture resistance when aluminum is used for the internal electrodes. However, conventional film capacitors use thermoplastic resins such as PET and PP (PPS, PEN) as dielectric materials, which have low melting points. Therefore, thermal degradation is likely to occur during metallikon application. Therefore, when using aluminum-based metallikon, which has a relatively high melting point, it is necessary to suppress thermal degradation of the film. To address this issue, several approaches have been proposed, including increasing the metallikon distance (spray distance) and alloying the metallikon metal to lower its melting point, thereby lowering the temperature of the metal particles when the aluminum-based metallikon is applied to the film. However, lowering the temperature of the metal particles during application reduces the adhesion of the metallikon film, ultimately resulting in reduced connectivity with the internal electrodes. This limits the improvement of capacitor characteristics such as ESR, making it difficult to provide a capacitor that combines the benefits of aluminum.

[0036] By using a highly heat-resistant thermosetting resin for the dielectric layer 13, it is expected that thermal degradation of the dielectric layer 13 due to the aluminum-based metallikon will be reduced, even if the metallikon (first metallikon region) 21, including the boundary region 30 that serves as the electrode lead, is formed using aluminum or an aluminum-based alloy. For this reason, it is believed that the aluminum-based metallikon layer can be formed while the temperature of the metallikon particles remains high, and a low-resistance capacitor 1 with good connectivity to the internal electrode 11 can be obtained. This invention demonstrates this and also discloses the conditions for providing a low-resistance capacitor 1 using an aluminum-based metallikon.

[0037] In particular, in thin-film polymer multilayer capacitors (PMLs) that use thermosetting resin as the dielectric and have a very thin dielectric layer 13, it is necessary to implant metallikon particles finely and powerfully to ensure sufficient connection between the external electrodes 20 and the main body 10. Therefore, shortening the spraying distance (metallikon distance) SD is particularly useful in PML manufacturing. Furthermore, the present invention discloses that shortening the spraying distance SD can provide a capacitor 1 with low resistance, and that applying metallikon from a short distance that is unthinkable in conventional film capacitors is effective. Therefore, by applying aluminum-based metallikon in the above-described configuration to thin-film polymer multilayer capacitors (PMLs), it is possible to provide capacitors with better characteristics than conventional metallikon made of brass, zinc, tin, or the like. Furthermore, in film capacitors, similar effects can be achieved in film capacitors (thermosetting film capacitors) that use thermosetting resin as the dielectric layer (dielectric film).

[0038] 2 includes the steps of depositing a monomer, in this example a thermosetting resin, in a vacuum chamber to form a monomer layer, and then irradiating the monomer layer with an electron beam to harden it, thereby forming a thermosetting resin dielectric layer 13; applying margin oil in a non-contact manner to form a margin; and depositing a metal material such as aluminum to form a metal thin film layer (electrode layer) 11. These steps are then continuously repeated on a rotating drum to produce a laminate (main body) 10 in which resin thin film layers 13 and metal thin film layers 11 are alternately stacked on the rotating drum. The laminate 10 is then cut, allowing aluminum or aluminum alloy metallikon layers 21 to be formed as external electrodes 20.

[0039] In thin-film polymer laminate capacitors and film capacitors, the formation of heavy edges by laminating aluminum or zinc on or near the end (boundary) 15 of the electrode layer 11 of the main body (laminate) 10 is being considered. For such capacitors, it is effective to use a thermosetting resin as the dielectric layer, as described above, and further to use Al or an Al-based alloy as the metallicon metal, and form a dense layer by irradiating it at a short distance or at a high temperature.

[0040] With metallicon (metal spraying), the adhesion improves basically the closer the distance (the higher the temperature). However, in the case of capacitors with thermoplastic dielectric layers such as conventional polypropylene or polyethylene terephthalate, such as film capacitors, there is a possibility that the film may deform or melt if the metallicon is heated to high temperatures. As a result, the adhesion between the electrode layer inside the body and the metallicon on the external electrode deteriorates, and in the case of aluminum or aluminum-based alloys, the deterioration in adhesion leads to a significant decrease in performance.

[0041] In contrast, the present invention successfully suppresses deterioration of bonding strength in capacitors using thermosetting resins for the dielectric layer. Furthermore, by forming a metallikon region using aluminum or an aluminum-based alloy, improved performance can be achieved. One factor contributing to this improved performance is that when the electrode layer 11 of the main body 10 is made of aluminum, the metallikon region 21 bonded to it is made of aluminum-based metallikon, enabling bonding between the same metals at the connection surface 15 and boundary region 30, improving physical and electrical connectivity. Another factor is that aluminum-based metallikon has higher electrical conductivity and lower resistance than zinc or brass, which are often used as metallikon in film capacitors. Furthermore, since the metallikon particle temperature can be increased, the adhesion strength of the metallikon particles also increases accordingly. Forming an external electrode using metallikon in this state is thought to improve the connectivity between the internal electrode layer 11 and the external electrode 20, thereby lowering resistance.

[0042] Regarding the bondability, in addition to the ability to increase the particle temperature, one of the factors is thought to be that the electrode layer 11 of the main body 10 and the metallikon region 21 inside the external electrode 20 are made of the same metal. Furthermore, in this case, not only is the resistance reduced, but corrosion (galvanic corrosion) that occurs with dissimilar metals does not occur, so there is also the advantage of being able to provide a capacitor with long-term reliability.

[0043] The above discloses a capacitor having a main body in which a dielectric layer made of a thermosetting resin and a metal electrode layer are laminated or wound, and an external electrode to which at least a portion of the main body is connected, the external electrode being a region in contact with the main body and including a dense metallikon region made of aluminum or an alloy containing aluminum. The porosity VR can be used as an index of denseness, and the porosity VR of the metallikon region may satisfy the following: 0 <VR≦11% (1)

[0044] The metallikon region may contain at least 80% aluminum, or may contain silicon, and the metallic electrode layer may be made of aluminum or an alloy containing aluminum. The thermosetting resin dielectric layer may contain at least one of an acrylic resin and a methacrylic resin. The thermosetting resin dielectric layer may have a thickness of 1.5 μm or less, and the external electrode may include multiple layers or regions, and may include an outer metallikon region that is provided in contact with the outside of the inner metallikon region and is made of a metal or alloy different from that of the inner metallikon region.

[0045] The publication discloses a method for manufacturing a capacitor, which includes manufacturing a body in which a dielectric layer made of a thermosetting resin and a metal electrode layer are laminated or wound, and forming an external electrode connected to at least a part of the body, wherein forming the external electrode includes spraying aluminum or an aluminum-containing alloy to contact the body to form a metallikon region, and maintaining the temperature of the boundary region between the body and the metallikon region at at least 150°C.

[0046] The above publication also discloses a different method for manufacturing a capacitor, which includes manufacturing a main body in which a dielectric layer made of a thermosetting resin and a metal electrode layer are laminated or wound, and forming an external electrode connected to at least a part of the main body, where forming the external electrode includes spraying aluminum or an aluminum-containing alloy so as to contact the main body to form a metallikon region, with the spraying distance kept at a maximum of 200 mm.

[0047] It should be noted that, although particular embodiments of the present invention have been described above, various other embodiments and modifications may be devised by those skilled in the art without departing from the scope and spirit of the present invention, and such other embodiments and modifications are within the scope of the following claims, which define the present invention.

Claims

1. a main body in which a dielectric layer made of a thermosetting resin and an electrode layer made of a metal are laminated or wound; an external electrode connected to at least a portion of the main body; The external electrode includes a metallikon region made of aluminum or an alloy containing aluminum, and the porosity VR of the metallikon region at least in a boundary region in contact with the thermosetting resin dielectric layer and the metal electrode layer satisfies the following: 0<VR≦11%

2. In claim 1, A capacitor, wherein the void ratio VR satisfies the following: 0<VR≦8%

3. In claim 1 or 2, The metallikon region comprises at least 80% aluminum.

4. In claim 3, The metallikon region comprises silicon.

5. In claim 1 or 2, A capacitor, wherein the metal electrode layer is made of aluminum or an alloy containing aluminum.

6. In claim 1 or 2, The dielectric layer made of thermosetting resin contains at least one of an acrylic resin and a methacrylic resin.

7. In claim 1 or 2, A capacitor, wherein the thickness of the dielectric layer made of thermosetting resin is 1.5 μm or less.

8. In claim 1 or 2, The external electrode includes an outer metallikon region that is provided in contact with the outside of the metallikon region and is made of a metal or alloy different from that of the metallikon region.

9. manufacturing a main body in which a dielectric layer made of a thermosetting resin and an electrode layer made of a metal are laminated or wound; forming an external electrode connected to at least a portion of the main body; The forming of the external electrode includes: forming a metallikon region by thermally spraying aluminum or an alloy containing aluminum so as to be in contact with the main body portion; A method for manufacturing a capacitor, wherein forming the metallikon region includes maintaining a temperature of at least 150°C when forming a boundary region that contacts at least the thermosetting resin dielectric layer and the metal electrode layer, and the porosity VR of the boundary region satisfies the following: 0<VR≦11%

10. manufacturing a main body in which a dielectric layer made of a thermosetting resin and an electrode layer made of a metal are laminated or wound; forming an external electrode connected to at least a portion of the main body; The forming of the external electrode includes: forming a metallikon region by thermally spraying aluminum or an alloy containing aluminum so as to be in contact with the main body portion; A method for manufacturing a capacitor, wherein forming the metallikon region includes maintaining a spraying distance of 200 mm at a maximum when forming a boundary region that contacts at least the thermosetting resin dielectric layer and the metal electrode layer, and the porosity VR of the boundary region satisfies the following. 0<VR≦11%

11. In claim 9 or 10, The method for manufacturing a capacitor, wherein the metallikon region comprises at least 80% aluminum.

12. In claim 9 or 10, The method for manufacturing a capacitor, wherein the metal electrode layer is made of aluminum or an alloy containing aluminum.

13. In claim 9 or 10, The method for manufacturing a capacitor, wherein the dielectric layer made of thermosetting resin contains at least one of an acrylic resin and a methacrylic resin.

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