Capacitor and manufacturing method for the same

Abstract

To provide a capacitor capable of handling large currents in a film capacitor including a PML.SOLUTION: A capacitor 1 has body part 10 on which a resin dielectric layer 13 and a metal electrode layer 11 are laminated or wound and an external electrode 20 to which at least a portion of the body part is connected. The external electrode is a metallikon area 21 that contacts the resin dielectric layer and the metal electrode layer and includes a metallikon area made of an aluminum alloy containing magnesium.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] The thin film polymer laminated capacitor described in Patent Document 1 includes a dielectric layer, an internal electrode layer including a first metal layer formed by vapor deposition of a first metal on the dielectric layer and a second metal layer formed by vapor deposition of a second metal on the first metal layer, which are alternately laminated and joined to form a chip-shaped laminate, and external electrodes formed on one end side and the other end side of the laminate, respectively. The laminate has a first region in which a first metal is formed on the dielectric layer and alternately laminated, and an edge region in which a second metal layer is formed on each of the layer connected to the one end side and the layer connected to the other end side of the first metal layer and alternately laminated. The first region has a capacitor functional region, and a heavy edge is formed in the edge region.

[0003] An example of a thin film polymer laminated capacitor (hereinafter referred to as PML) includes a metal electrode layer vapor-deposited with aluminum and a main body (capacitor main body, capacitor element) formed by laminating a heat-resistant thermosetting resin, such as an acrylic resin or a methacrylic resin (for example, tricyclodecane dimethanol diacrylate or tricyclodecane dimethanol dimethacrylate), as a dielectric layer. The PML further has an external electrode connected to the end of the main body, and the connection portion of the external electrode to the main body includes a layer (metallicon layer) formed by spraying (spraying, metallicon) molten metal. In a conventional film capacitor in which the main body is manufactured by winding a dielectric layer and an electrode layer, an external electrode including a metallicon layer is provided to connect the main body to an external circuit.

[0004] As the metallization metal for forming the metallization layer, brass (Cu + Zn) is used, which has a high melting point and is easy to handle reflow, and furthermore, plating for the exterior of the external electrode is also easy. Another example of the metallization metal is aluminum, which has excellent adhesion to the electrode layer inside the main body and good moisture resistance. As shown in Cited Document 2, some of the conditions contributing to the performance improvement when aluminum is adopted as the metallization metal have been disclosed by the applicant of the present application.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, more current characteristics have been required for film capacitors including PML, and one of them is to cope with high-current applications such as electric vehicles. The inventors of the present application have found that by adopting aluminum as the metallization metal, the pulse current characteristics, which are one of the indicators for coping with high-current applications, can be significantly improved. Considering future applications of PML, it is desired that this characteristic can be further improved.

Means for Solving the Problems

[0007] One aspect of the present invention has a main body portion in which a resin dielectric layer and a metal electrode layer are laminated or wound, and an external electrode to which at least a part of the main body portion is connected. The external electrode is a metallicon region in contact with the resin dielectric layer and the metal electrode layer, and is a capacitor including a metallicon region made of an aluminum alloy containing magnesium. The metallicon region may be made of an aluminum alloy containing 0.2 to 6.0% by weight of magnesium, or may be made of an aluminum alloy containing 1.5 to 5.5% by weight of magnesium.

[0008] The inventors have found that by adopting aluminum as the metal for manufacturing metallicon, the resistance to the pulse current test is obtained at about 1.5 times or more than that in the case of brass, and further, by adopting an aluminum alloy containing magnesium, a resistance exceeding 2 times is obtained. Therefore, a capacitor made of an aluminum alloy containing magnesium in the metallicon region can provide a capacitor more suitable for high-current applications.

[0009] The metal electrode layer of the main body portion may be made of aluminum or an alloy containing aluminum, and the resin dielectric layer may be made of a thermosetting resin. The thermosetting resin may contain at least one of an acrylic resin and a methacrylic resin. Also, the thickness of the resin dielectric layer may be 1.5 μm or less.

[0010] The external electrode may include an outer metallicon region made of a metal or alloy different from the metallicon region, provided in contact with the outside of the metallicon region. The outer metallicon region may contain brass. Further, the porosity VR of at least the boundary region of the metallicon region in contact with the resin dielectric layer and the metal electrode layer may satisfy the following condition (1). 0 < VR ≦ 11% ··· (1)

[0011] One of the other aspects of the present invention is a method for manufacturing a capacitor, which includes manufacturing a main body portion in which a dielectric layer made of resin and an electrode layer made of metal are laminated or wound, and forming an external electrode connected to at least a part of the main body portion. The step of forming the external electrode includes spraying an aluminum alloy containing magnesium so as to contact the main body portion to form a metallicon region. Forming the metallicon region may include spraying an aluminum alloy containing 0.2 to 6.0% by weight of magnesium.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0013] FIG. 1 shows an example of a capacitor according to the present invention. The capacitor 1 whose external appearance is shown in FIG. 1(a) is an example of a thin film polymer laminated capacitor (hereinafter referred to as PML), and includes a main body (main body part, laminate, capacitor element) 10 in which a dielectric layer 13 and an electrode layer 11 are laminated integrally, 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 provided at the center in the thickness direction for expressing capacitance, dummy layers 8 disposed above and below the active layer 7 that do not express capacitance, and protective layers 9 disposed above and below the dummy layers 8. The active layer 7 and the dummy layer 8 have a structure in which a resin layer (dielectric layer) 13 and an electrode layer 11 are laminated, and the protective layer 9 is composed of only resin. The external electrode 20 is formed so as to be joined to the electrode layer 11 and the resin layer 13 of the active layer 7 and the dummy layer 8, and includes an internal metallicon layer 25, a copper plating layer 27 covering the periphery thereof, and a tin plating layer 28 further covering the outside.

[0014] The metallicon layer 25 includes an inner region (inner layer, first metallicon region) 21 in contact with the dielectric layer 13 and the electrode layer 11 of the main body 10, and an outer region (outer layer, second metallicon region) 22 provided outside the inner region 21. The first metallicon region 21 includes a boundary region 30 where a metallicon metal (first metallicon metal) is sprayed on the cut boundary surface 15 of the main body 10. In this example, the first metallicon metal is an aluminum alloy containing magnesium, and the first metallicon region 21 includes a boundary region 30 made of an aluminum alloy containing magnesium in contact with the main body 10. The metallicon layer 25 may be formed entirely of the same metal, in this example, an aluminum alloy containing magnesium. On the other hand, the inner first metallicon region 21 may be formed of an aluminum alloy containing magnesium that prioritizes the connection performance with the main body 10, and the outer second metallicon region 22 may be formed of a material that prioritizes the external connection performance. The second metallicon region 22 may be formed of a material having high adhesion to the outer plating layer 27 and high heat resistance during reflow or the like, for example, brass. The second metallicon region 22 may be copper, tin, zinc, or an alloy containing any of them.

[0015] Figure 2 shows an enlarged cross-section of a part of the active layer 7 of the main body 10. The active layer 7 of the main body 10 is a part where a plurality of dielectric layers 13 and a plurality of electrode layers 11 are alternately laminated. In the boundary region 30, the ends (end portions, edge portions, connection portions) of the respective electrode layers 11 and the ends of the respective dielectric layers 13 are joined to the metallicon layer 21 of the external electrode 20, and each electrode layer 11 is electrically connected to the metallicon layer 21. The electrode layer 11 includes a thin-film internal electrode portion (internal electrode layer) 15 that widely contacts the dielectric layer 13 inside the active layer 7 to form a capacitance, and a heavy edge portion 16 where the portion of the end connected to the metallicon layer 21 is thicker than the internal electrode portion 15. In this example, the heavy edge portion 16 of the electrode layer 11 is composed of the electrode layer 11 and a layer (heavy portion) 12 laminated on the electrode layer 11. Therefore, the internal electrode layer 15 is composed of the electrode layer 11, the heavy edge portion 16 is composed of the heavy portion 12 laminated on the electrode layer 11, the heavy edge portion 16 is connected to the internal electrode layer 15, and one end of the heavy edge portion 16 is exposed on the connection surface 30. When providing a high withstand voltage capacitor 1, it is desirable that the thickness of the internal electrode layer (internal electrode portion) 15 is thin. For example, it may be 0.01 μm, and may be even thinner, 0.005 μm (5 nm). On the other hand, considering the connection with the external electrode 20, a thickness of about 0.01 μm or more is considered necessary. In the capacitor 1 provided with the thin-film type internal electrode portion 15, the heavy edge portion 16 may be provided. In addition, when the internal electrode portion 15 has a sufficient thickness, the heavy edge portion 16 may not be provided. The heavy portion 12 may be made of the same material as the internal electrode layer 15 or a different material. An example of the heavy portion 12 is a layer formed by vapor depositing zinc.

[0016] An example of the resin constituting the dielectric layer 13 is a thermosetting resin, which includes an acrylic polymer. An example of the resin that can be adopted in the thin-film polymer laminated capacitor 1 is a polymerized product of any one or more of tricyclodecane dimethanol dimethacrylate or tricyclodecane dimethanol diacrylate, but the resin constituting the dielectric layer 13 is not limited to this. In order to provide a small, thin, and large-capacity capacitor, the dielectric layer 13 may be sufficiently thin, and the main body 10 may have a sufficient number of laminations. For example, the thickness of the dielectric layer 13 may be 0.1 to 1.5 μm, may be 0.2 to 1.2 μm, and the number of laminations may be 1000 or more. The thin-film dielectric layer 13 can be obtained by vapor-depositing a thermosetting resin as a monomer in a reduced-pressure environment (in vacuum) and irradiating it with an electron beam or the like to cure it. The capacitor 1 provided with the dielectric layer 13 made of a thermosetting resin has a higher heat-resistant temperature compared with the one provided with a thermoplastic resin and can also cope with reflow, so it can be provided as a more suitable element for surface mounting.

[0017] The electrode layer 11 may be formed of a conductive metal, for example, at least any one of aluminum, zinc, copper, gold, silver, or an alloy containing these. As the capacitor 1 for high voltage, the withstand voltage can be improved by reducing the thickness of the electrode functioning as a capacitor, that is, the internal electrode layer 15. For example, the withstand voltage may be 400 V or more, the thickness of the internal electrode layer 15 may be about 3 to 50 nm, and may be about 5 to 30 nm. The surface resistivity may be used for the management of the thickness of the thin-film electrode, and the surface resistivity of the internal electrode layer 15 may be 5 to 80 Ω / □ (Ω / sq.), may be 15 to 60 Ω / □, and may be 20 to 50 Ω / □.

[0018] The electrode layer 11 of the capacitor 1 may further include a dummy heavy edge portion 17 separated from the internal electrode layer 15 by a gap 19, and one end of the dummy heavy edge portion 17 is exposed on the connection surface 30. Since the dummy heavy edge portion 17 is separated from the internal electrode layer 15, it does not contribute to the capacitance of the capacitor 1. However, it is useful for obtaining mechanical connection strength with the metallicon (metal spraying) layer 21, and maintains or strengthens the connection with the metallicon region 21 together with the heavy edge portion 16 integrated with the internal electrode layer 15. In this example, the layer 12 constituting the heavy edge portion 16 may be laminated on the upper side of the electrode layer 11, may be laminated on the lower side, or may be laminated on both the upper and lower surfaces. The heavy edge portion 16 is not limited to a two-layer structure, and may be a single-layer structure or a structure of three or more layers.

[0019] FIG. 3 shows an example of a method for manufacturing the PML1. FIG. 4 shows the specifications of the PMLs used as examples and comparative examples. The specifications of the electrode layer 11 and the dielectric layer 13 are as follows. Thickness of the electrode layer 11: 10 nm Material of the electrode layer 11: Aluminum (Al) Material of the heavy portion 12: Zinc (Zn) Thickness of the dielectric layer 13: 1.0 μm Material of the dielectric layer 13: Thermosetting resin (methacrylic resin) (In this example, tricyclodecane dimethanol dimethacrylate)

[0020] In the manufacturing method 40 shown in FIG. 3, in step 41, a laminate that serves as the base of the main body (main body portion) 10 is manufactured. An example of a method for manufacturing a laminate is a method of forming each layer by vapor deposition. On a drum that rotates in a reduced-pressure environment (vacuum environment) inside a vacuum chamber, a dielectric layer 13 and an electrode layer 11 (including the heavy portion 12) are formed on each other by vapor deposition to manufacture an apparatus for manufacturing a laminate that serves as the base of the main body portion 10. The laminate may be manufactured using other methods such as coating or printing. In this example, the thermosetting resin applied as the dielectric layer 13 is cured by an electron beam irradiator or the like and formed into the dielectric layer 13. Further, the surface of the dielectric layer 13 is plasma-treated by a plasma processing apparatus for the next process. Before forming the electrode layer 11, an oil margin may be applied on the dielectric layer 13 by a patterning unit to pattern the electrode layer 11. When using a pre-manufactured film or the like as the dielectric layer as in a film capacitor or the like, the step of forming the dielectric layer may not be necessary and may be performed separately from the step of forming the electrode layer.

[0021] In step 42, the laminate is cut into strips to form the main body portion 10 in a strip state (stick state). The main body portion 10 in a strip state may be formed directly from the laminate, or the main body portion 10 in a strip state may be manufactured with other processes such as a planarization press process or a card cutting process interposed. In step 43, plasma ashing is performed on the surface cut into strips as a connection portion (connection surface) with the external electrode 20. As an example, plasma ashing may be performed using a mixed gas of oxygen and carbon tetrafluoride to form a connection portion between the metallicon and the internal electrode. By plasma ashing, the dielectric on the cut surface of the strip cutting can be burned off and the internal electrode (electrode layer) 11 can be exposed.

[0022] In step 44, a metallicon layer (first metallicon layer, first metallicon region) 21 that becomes the external electrode 20 is formed on the plasma-ashed connection surface by metallicon (metal spraying). In this example, as an example, an aluminum alloy containing magnesium (Al-5%Mg, Al95%+Mg5% (% indicates weight%, the same applies hereinafter)) was sprayed to form the first metallicon layer 21. Also, as Comparative Example 1, brass (Cu65%+Zn35%) was sprayed, and as Comparative Example 2, aluminum (Al, (Al99.9%)) was sprayed to form the first metallicon layer 21. Then, further, in step 45, brass was sprayed as the second metallicon metal to form the second metallicon layer 22. When generating the first metallicon layer 21 in step 44, as disclosed in International Publication WO2023 / 189919 (Patent Document 2), in order to make the porosity VR in the boundary region 30 within the range of condition (1), the spraying distance (metallicon distance) SD to the boundary surface was set to 200 mm or less, and the surface temperature ST of the boundary surface was made 150°C or higher.

[0023] In step 46, a copper plating layer 27 and a tin plating layer 28 were formed in order by an electrolytic plating method or the like. The tin plating layer 28 is effective for improving the solder wetting property of the external electrode 20. Then, processes required for the external electrode 20 such as heat treatment are performed. Further, in step 47, the strip-shaped main body 10 with the external electrode 20 formed thereon was cut into a chip shape together with the external electrode 20, thereby manufacturing the PML1 in which the external electrode 20 is connected to the main body 10. Note that the process shown in FIG. 3 shows a typical process, and other processes may be implemented or there may be processes that are not implemented.

[0024] Figure 4 shows the main specifications and initial characteristics of the capacitors (PMLs) manufactured as the example, Comparative Example 1, and Comparative Example 2. Note that the numbers after the metal species described in the metallicon column in Figure 4 indicate wt%. As shown in Figure 4, it can be seen that the initial characteristics of all PMLs are common and good. Among them, the initial characteristics of the example in which the metallicon layer 21 was formed of an aluminum alloy containing magnesium and Comparative Example 2 formed of aluminum were particularly good. Also, a 125°C life test (1000 hours), a 40°C 95% RH life test (1000 hours), and a temperature cycle test (-55°C ⇔ +125°C, 50 cycles) were conducted on these PMLs, but there was no significant difference and the results were good. Further, after the PML including the external electrode 20 was manufactured, the external electrode 20 including the main body 10 was cut, and the cross section was observed with a digital microscope (for example, VHX-5000 manufactured by Keyence), and the porosity VR (%) of the metallicon layer 21 was obtained by the following formula (2). The observation magnification was 1000 times, voids with a representative length of 0.15 μm or more were detected, and the average value of the values observed at at least three locations on the cross section was adopted. Porosity VR (%) = (total void area / total observed area) × 100 ···(2) In these PMLs 1, it was confirmed that the porosity VR of the metallicon layer 21 satisfies the following condition (1). 0 < VR ≦ 11% ···(1)

[0025] Figures 5 and 6 show an example of the results of the pulse current resistance test. Figure 5 shows the capacitance change (measurement result by AC with a frequency of 1 kHz), and Figure 6 shows the change in ESR (equivalent series resistance) (measurement result by AC with a frequency of 100 kHz). Note that the conditions of the pulse (rectangular wave) used in the pulse current resistance test are as follows. Frequency (Hz): 60 Number of cycles: 1000 Discharge resistance (Ω): 0.5

[0026] As shown in FIG. 5, in the PML of Comparative Example 1 in which the first metallization layer (metallization region) 21 is formed of brass, a pulse voltage of about 200 V results in a capacitance change (capacitance decrease) being observed, whereas in the PML of Comparative Example 2 in which the first metallization layer 21 is formed of aluminum, no capacitance change (capacitance decrease) is observed even when the pulse voltage exceeds 300 V. It has been found that forming the first metallization layer 21 of aluminum improves the pulse current resistance characteristic (dV / dt). Further, in the PML of Comparative Example 2 in which the first metallization layer (metallization region) 21 is formed of aluminum (Al), a capacitance change (capacitance decrease) is observed at a pulse voltage of about 350 V, whereas in the PML1 of the Example in which the first metallization layer 21 is formed of an aluminum alloy containing magnesium (Al-Mg alloy), no capacitance change (capacitance decrease) is observed even when the pulse voltage exceeds 450 V. It has been found that forming the first metallization layer 21 of an Al-Mg alloy further improves the pulse current resistance characteristic (dV / dt).

[0027] As shown in FIG. 6, looking at the change in ESR, in the PML of Comparative Example 1 in which the first metallization layer (metallization region) 21 is formed of brass, a tendency for the ESR to increase rapidly is observed when the pulse voltage exceeds 200 V, whereas in the PML of Comparative Example 2 in which the first metallization layer 21 is formed of aluminum, no increase in ESR is observed even when the pulse voltage exceeds 300 V. From the change in ESR as well, it has been found that forming the first metallization layer 21 of aluminum improves the pulse current resistance characteristic (dV / dt).

[0028] Further, in the PML of Comparative Example 2 in which the first metallization layer (metallization region) 21 is formed of aluminum (Al), a tendency for the rate of increase in ESR to increase is observed when the pulse voltage exceeds 350 V, whereas in the PML1 of the Example in which the first metallization layer 21 is formed of an Al-Mg alloy, no tendency for a change in the rate of increase in ESR is observed even when the pulse voltage exceeds 450 V. From the change in ESR as well, it has been found that forming the first metallization layer 21 of an Al-Mg alloy further improves the pulse current resistance characteristic (dV / dt).

[0029] Therefore, by changing the first metallization layer (metallization region) 21 in contact with the dielectric layer 13 and the electrode layer 11 of the main body 10 from brass to aluminum, the pulse current withstand characteristics (dV / dt) can be improved, and it has been found that the pulse current withstand characteristics (dV / dt) can be further improved by changing it to an Al-Mg alloy. For this reason, it has been found that by providing the PML1 including the first metallization layer 21 made of an Al-Mg alloy, a capacitor suitable for high-current applications can be provided.

[0030] For the first layer 21 of the external electrode 20 connected to the main body (laminated body) 10 of the PML, brass metallization has been adopted, but the connection resistance with the laminated body 10 is relatively high, and there has been a tendency for large characteristic variations. In contrast, it has been proposed that the connection resistance can be reduced by changing the metallization metal of the first layer 21 to aluminum. However, in conventional film capacitors using thermoplastic resins such as PET and PP (PPS, PEN), since these materials have a low melting point, when trying to apply an aluminum-based metallization with a relatively high melting point, measures such as increasing the metallization distance (spraying distance) are required to lower the temperature of the metal particles during adhesion. As a result, the adhesion of the metallization film decreases, leading to a decrease in the connectivity with the internal electrode, and thus it has been difficult to improve capacitor characteristics such as ESR and provide a capacitor having the merit of adopting aluminum.

[0031] In contrast, in International Publication WO2023 / 189919 (Patent Document 2), the applicant of the present application uses a high heat-resistant thermosetting resin as the dielectric material for the dielectric layer 13, thereby reducing the thermal degradation of the dielectric layer 13 due to the aluminum-based metallization. Furthermore, as shown in condition (1), by shortening the spraying distance (metallization distance) SD, the porosity VR of the boundary region 30 is managed. Thereby, the merit of forming the first metallization layer (metallization region) 21 with aluminum can be realized, and the improvement in performance appearing as the connectivity and connection resistance of the capacitor such as ESR can be realized.

[0032] Furthermore, in this specification, it has been found that in the PML in which the first metallization layer (metallization region) 21 is formed of aluminum, the pulse current resistance characteristics can also be improved as compared with the PML in which the first metallization layer is formed of brass. And in the PML1 in which the first metallization layer (metallization region) 21 is formed of an Al-Mg alloy, it has been found that the pulse current resistance characteristics can be further improved as compared with the PML in which the first metallization layer (metallization region) 21 is formed of aluminum.

[0033] At present, the reason for the significant improvement in the pulse current resistance characteristics in the PML1 in which the first metallization layer (metallization region) 21 is formed of an Al-Mg alloy is not clear. For example, the Al-Mg binary equilibrium phase diagram can be compared with the Al-Si binary equilibrium phase diagram conventionally disclosed as an aluminum alloy for forming the metallization region. The melting point of aluminum is 660.4 °C, and the Al-Si alloy is a eutectic system with a eutectic point at 577 °C and 12.6%. However, the maximum Si solid solubility in the α(Al) solid solution is 1.65%, and the solid solubility decreases with decreasing temperature. Due to this decrease in solid solubility, the Si phase precipitates, but the precipitation hardening is very small. The Si phase crystallized eutectically hardly dissolves aluminum, and is known to have high hardness and a small thermal expansion coefficient.

[0034] On the other hand, in the Al-Mg alloy system, the maximum Mg solid solubility on the Al side is 18.6 at% at the eutectic temperature of 450 °C. The solid solubility of Mg decreases with decreasing temperature, but is extremely gentle compared with the Al-Si alloy system. In addition, the Al-Mg alloy is generally regarded as one of the materials with good corrosion resistance, formability, and weldability. On the other hand, although the Al-Mg alloy is used for magnetic disk materials, wheel materials, can materials, thick plates, etc., it has been pointed out that there are problems such as surface defects caused by porosity, punctiform defects during cutting, and bulging. However, it is known that if the Mg addition amount is about 6% or less, the porosity is small and fine, and the amount of porosity tends to decrease as the Mg addition amount decreases.

[0035] Although the behavior and properties in the metallikon spraying of the Al-Mg alloy system are being confirmed, it is considered that the characteristics of the above Al-Mg alloy appear in the effect of the invention of the present application that the melting point is more likely to decrease than that of aluminum or Al-Si alloy, the spraying is stable, and the variation in the quality of the metallikon formed by spraying can be suppressed.

[0036] That is, in the present invention, by forming the metallikon region 21 with the Al-Mg alloy system, the workability and stability are improved compared to the PML provided with the metallikon region made of aluminum or Al-Si alloy disclosed in Patent Document 2, and the workability and stability comparable to those of the PML forming the metallikon region with brass are obtained. As for electrical characteristics such as ESR and connection resistance, it has been found that they are equal to or higher than those of the PML provided with the metallikon region made of aluminum or Al-Si alloy.

[0037] Furthermore, focusing on the pulse current characteristics (dV / dt), it has been found that the PML1 provided with the metallikon region 21 made of Al-Mg alloy surpasses the PML provided with the metallikon region made of aluminum. Due to the characteristics of the Al-Mg system, it is assumed that the metallikon particles of the Al-Mg alloy become finer, so the density of the metallikon region 21 increases, and it is assumed that the connectivity is better than that of the metallikon region 21 made of aluminum. Furthermore, since the Al-Mg alloy wire is harder than the aluminum wire, during arc spraying, the contact points between the metal wires are stable, and the effect of stable spraying can be obtained. This is also considered to contribute to making the metallikon particles finer and improving the connectivity. In recent years, the current characteristics have been increasingly required for film capacitors, and in electric vehicles and the like, it is required to cope with high-current applications. It has been found that the present invention can provide the PML1 that can sufficiently cope with such applications.

[0038] In addition, considering that in the Al-Mg system, the problem of porosity may occur as the Mg content increases, in order to satisfy the porosity VR of condition (1), the metallization region 21 is preferably made of an aluminum alloy (Al-Mg alloy) containing 0.2 to 6.0% by weight of magnesium, and more preferably made of an aluminum alloy containing 1.5 to 5.5% by weight of magnesium.

[0039] Also, considering that the electrical connectivity with the Al-Mg alloy-made metallization region 21 can be improved, the metal electrode layer 11 of the main body 10 is desirably made of aluminum or an alloy containing aluminum. Further, considering spraying the Al-Mg alloy under conditions that satisfy the porosity VR of condition (1), the resin dielectric layer 13 of the main body 10 is preferably made of a thermosetting resin, and desirably contains at least one of an acrylic resin and a methacrylic resin. Also, in order to miniaturize and enhance the performance of the capacitor, it is desirable to appropriately set the thickness of the resin dielectric layer 13, for example, desirably 1.5 μm or less.

[0040] The external electrode 20 may include an outer metallization region (second metallization layer) 22 made of a metal or alloy different from the Al-Mg alloy, which is provided in contact with the outside of the Al-Mg alloy-made metallization region (first metallization layer) 21. In the PML1 of the embodiment, a brass-made metallization region 22 with good connectivity to the plating layers 27 and 28 covering the outside of the metallization layer 25 is formed. The external electrode 20 may be formed of a single metallization region or a metallization region of three or more layers. The capacitor 1 provided with the brass-made metallization region 22 has a high melting temperature and high affinity with the plating layer covering the external electrode 20, and is one of the preferred examples as a surface mount component (SMD) attached by reflow or the like.

[0041] Although the shape of the surface mount component has been described in this specification, it may also be applied to capacitors in which lead wires or bus bars are joined to external electrodes, and further to capacitors having an exterior covered with a case or exterior resin (lead wire type, case products, block products, large products, etc.). Also, a plating layer covering the outside of the metallicon layer may not be provided.

[0042] Note that, in the above, specific embodiments of the present invention have been described, but various other embodiments and modifications can be conceived by those skilled in the art without departing from the scope and spirit of the present invention, and such other embodiments and modifications are the subject of the following claims, and the present invention is defined by the following claims.

Claims

1. A main body in which a resin dielectric layer and a metal electrode layer are laminated or wound, and an external electrode connected to at least a part of the main body, wherein the external electrode is a metallization region in contact with the resin dielectric layer and the metal electrode layer, and includes a metallization region made of an aluminum alloy containing magnesium, a capacitor.

2. In Claim 1, the metallization region is made of an aluminum alloy containing 0.2 to 6.0% by weight of magnesium, a capacitor.

3. In Claim 1, the metallization region is made of an aluminum alloy containing 1.5 to 5.5% by weight of magnesium, a capacitor.

4. In any one of Claims 1 to 3, the metal electrode layer is made of aluminum or an alloy containing aluminum, a capacitor.

5. In any one of Claims 1 to 3, the resin dielectric layer includes a thermosetting resin, a capacitor.

6. In Claim 5, the dielectric layer made of the thermosetting resin includes at least one of an acrylic resin and a methacrylic resin, a capacitor.

7. In any one of Claims 1 to 3, the thickness of the resin dielectric layer is 1.5 μm or less, a capacitor.

8. In any one of Claims 1 to 3, the external electrode includes an outer metallization region made of a metal or alloy different from the metallization region, provided in contact with the outside of the metallization region, a capacitor.

9. In Claim 8, the outer metallization region includes brass, a capacitor.

10. In any one of Claims 1 to 3, a capacitor in which the porosity VR of at least a boundary region of the metallization region in contact with the resin dielectric layer and the metal electrode layer satisfies the following: 0 < VR ≤ 11%

11. Manufacturing a main body in which a resin dielectric layer and a metal electrode layer are laminated or wound, and forming an external electrode connected to at least a part of the main body, wherein forming the external electrode includes forming a metallization region by spraying an aluminum alloy containing magnesium so as to be in contact with the main body, a method for manufacturing a capacitor.

12. In Claim 11, forming the metallization region includes spraying the aluminum alloy containing 0.2 to 6.0% by weight of magnesium, a method for manufacturing a capacitor.

13. In claim 11 or 12, The method for manufacturing a capacitor, wherein the metal electrode layer is made of aluminum or an alloy containing aluminum.

14. In claim 11 or 12, The method for manufacturing a capacitor, wherein the dielectric layer is made of a thermosetting resin and contains at least one of an acrylic resin and a methacrylic resin.

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