Capacitor and method for manufacturing the same

Abstract

Provided is a capacitor (1) having a main body (10) in which a plurality of dielectric layers (13) and a plurality of electrode layers (11) are laminated, and an external electrode (20) connected to at least part of the main body, wherein, prior to formation of the external electrode by metal spraying (metallikon) on the main body, at least part of a connection surface (30) to be subjected to metal spraying is scanned by a laser beam (51), and a scanning mark (55) composed of a relief (35) produced by the laser beam is formed in at least part of the connection surface.

Description

Technical Field

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

Background Art

[0002] Japanese Patent Laid-Open No. 2004-6495 discloses a laminated capacitor in which a laminated substrate obtained by vapor-depositing aluminum on a dielectric resin layer and stacking them alternately is cut into a stick shape, and then a mixed gas containing two or more of CF3, CF4, and O2 is activated to form a plasma state, and a chemical dry etching treatment is performed on the cut surface to an etching depth of 10 to 100 μm, and a metal spraying is performed on the etched surface to form an electrode lead-out portion, and a method for manufacturing the same.

Disclosure of the Invention

[0003] Stacked capacitors are provided that are small in size, have a high withstand voltage, and low ESR. Further, it is important that the connection with the external electrode is good and stable, and good withstand voltage characteristics can be obtained. For example, for a film capacitor, a thin-film polymer laminated capacitor can reduce the thickness of the dielectric layer to 1.5 μm or less, and can provide a small-sized capacitor with a high withstand voltage and low ESR. On the other hand, when the surface resistivity (sheet resistivity) of the electrode portion (internal electrode portion) of the capacitor portion is thinned so as to be sufficiently high in order to increase the withstand voltage, the connection portion with the external electrode also becomes thin. Therefore, the connection resistance of the connection portion increases, and it becomes difficult to sufficiently reduce the ESR. The adoption of a heavy-edge structure in which only the edge portion is made thicker has also been considered. In order to provide a capacitor that is small in size, has a high withstand voltage, and has a lower connection resistance, it is important to further stabilize the connection with the external electrode.

[0004] One aspect of the present invention is a method for manufacturing a capacitor having a main body portion in which a plurality of dielectric layers and a plurality of electrode layers are alternately laminated, and an external electrode connected to at least a part of the main body portion. This manufacturing method includes scanning at least a part of a connection surface of the main body portion to be metal sprayed, which is a connection surface where ends of the plurality of dielectric layers and the plurality of electrode layers are exposed, with laser light before forming the external electrode by metal spraying on the main body portion. Scanning the connection surface with laser light (scanning step, scanning process) may be used instead of or together with surface treatment by plasma. By irradiating the connection surface with laser light, the connection surface can be processed so that changes in the structure and / or shape of at least a part of the connection surface are repeated at appropriate intervals (pitches). For example, in order to obtain a stable connection with the external electrode formed by metal spraying, an uneven shape may be stably formed on the connection surface. For the treatment by laser light, the treatment by plasma is basically ashing of the dielectric layer, the amount of ashing depends on the film formation state of the dielectric layer, and furthermore, since there is a bias in the distribution of the plasma, variations in the treatment amount are likely to occur. Therefore, it is difficult to control the state of the electrode layer on the connection surface by plasma treatment or by plasma treatment alone. In the present invention, the connection surface is scanned with laser light. In this method, it is possible to forcibly melt and evaporate not only the ends of the dielectric layers but also the ends of the electrode layers, and a configuration or shape with higher connectivity to metal spraying can be more stably introduced two-dimensionally or three-dimensionally and periodically on the connection surface.

[0005] The process (step) of scanning with laser light may include forming a scanning mark by laser light on the connection surface. The scanning mark may be a three-dimensional scanning mark. The process of scanning with laser light may include forming irregularities on at least a part of the connection surface. As an example, by scanning the connection surface with laser light having a relatively large spot diameter, irregularities may be formed due to the film formation state of the dielectric layer and / or the electrode layer. As another example, by scanning with laser light having a relatively small spot diameter, a scanning mark with irregularities in a predetermined direction or shape can be formed, and irregularities in a predetermined shape may be forcibly formed on the connection surface.

[0006] The scanning process may include forming, on at least a part of the connection surface, a region where at least a part of the ends of a plurality of electrode layers has retreated with respect to at least a part of the ends of a plurality of dielectric layers exposed on the connection surface. The electrode layer formed of a metal such as aluminum may be more likely to evaporate than the dielectric layer by laser irradiation, and by the ends of the electrode layer retreating more than the ends of the dielectric layer by laser irradiation, an uneven structure with high connectivity to metal spraying may be formed.

[0007] Each of the plurality of electrode layers may be connected to an internal electrode layer laminated inside the main body portion, and may have a thick film heavy edge portion with respect to the internal electrode layer, with one end exposed on the connection surface. The scanning process may include scanning the ends of the plurality of heavy edge portions and the ends of the plurality of dielectric layers appearing on the connection surface with laser light. If the electrode layer appearing on the connection surface becomes too thick, the connectivity with the external electrode tends to decrease, but the decrease in connectivity can be suppressed by irradiating laser light to create stable irregularities. Also, by the heavier edge portion with a larger film thickness retreating due to laser irradiation, the irregularities between the dielectric layer and the electrode layer are more likely to become larger, and the connectivity with the external electrode can be improved.

[0008] Examples of the laser light used for the scanning process may include at least any one of a YVO4 laser, a YAG laser, a fiber laser, a semiconductor laser, an excimer laser, and a CO2 laser.

[0009] The manufacturing method may further include the following steps. · Forming a laminate by alternately depositing a plurality of dielectric layers and a plurality of electrode layers. · Forming a main body in a strip state (stick state) obtained by strip cutting from the laminate. · Scanning the strip-cut surface with laser light as a connection surface. · Forming an external electrode by metal spraying on the connection surface scanned with laser light. · Cutting the main body in a strip state with the external electrode into a chip shape together with the external electrode. When the plasma treatment can be omitted by using the process of scanning with laser light, the processes after the strip cutting can be performed in the air, and the manufacturing process of the capacitor can be further simplified. Therefore, a capacitor can be provided at a lower cost.

[0010] One of the other aspects of the present invention is a capacitor having a main body in which a plurality of dielectric layers and a plurality of electrode layers are laminated, and an external electrode connected to at least a part of the main body. At least a part of the connection surface of the main body of this capacitor, on which the external electrode is formed by metal spraying, includes scanning marks by laser light. The plurality of electrode layers are connected to an internal electrode layer laminated inside the main body, one end of which is exposed on the connection surface, and may include a thick-film heavy edge portion with respect to the internal electrode layer. The connection surface may include scanning marks extending across the ends of the plurality of heavy edge portions appearing on the connection surface and the ends of the plurality of dielectric layers.

[0011] One aspect of another embodiment of the present invention is a capacitor having a main body portion in which a plurality of dielectric layers and a plurality of electrode layers are laminated, and an external electrode connected to at least a part of the main body portion, wherein at least a part of a connection surface of the main body portion where the external electrode is formed by metal spraying includes unevenness in which at least a part of the ends of the plurality of electrode layers recedes with respect to a part of the ends of the plurality of dielectric layers. Each of the plurality of electrode layers of this capacitor is connected to an internal electrode layer laminated inside the main body portion, one end is exposed on the connection surface, and it has a thick film heavy edge portion with respect to the internal electrode layer, and at least a part of the ends of the plurality of heavy edge portions appearing on the connection surface may recede with respect to a part of the ends of the plurality of dielectric layers.

Brief Description of the Drawings

[0012]

Figure 1

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Figure 8

[0013] Fig. 1 shows an example of a capacitor according to the present invention. As a capacitor 1 having a main body (main body part, laminate) 10 in which a plurality of dielectric layers and a plurality of electrode layers are alternately laminated and integrated, and an external electrode 20 connected to the main body 10, a thin-film polymer laminated capacitor is known. The capacitor 1 whose appearance is shown in Fig. 1(a) is an example of a thin-film polymer laminated capacitor. As shown in the cross-sectional view of Fig. 1(b), the main body part 10 includes an active layer 7 that exhibits capacitance and is provided at the center in the thickness direction, dummy layers 8 that are disposed above and below the active layer 7 and do not exhibit capacitance, and protective layers 9 that are disposed above and below the dummy layers 8. The active layer 7 and the dummy layer 8 have a configuration in which a plurality of resin layers (dielectric layers) 13 and a plurality of electrode layers 11 are alternately laminated, and the protective layer 9 is composed only of resin. The external electrode 20 is formed by metal spraying (metallization) so as to be joined to a connection surface 30 where the ends of the plurality of electrode layers 11 of the active layer 7 and the dummy layer 8 and the ends of the plurality of resin layers 13 appear, and includes an internal metallization layer (metal spraying layer, for example, brass metallization) 21, a copper plating layer 22 that covers the periphery thereof, and a tin plating layer 23 that further covers the outside.

[0014] FIG. 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. Ideally, at the connection surface 30, the ends (end portions, edge portions, connection portions, connection regions, connection boundaries) 31 of the respective electrode layers 11 and the ends 33 of the respective dielectric layers 13 are joined to the metallicon layer 21 of the external electrode 20, and each electrode layer 11 is also 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 31 where the external electrode 20 (metallicon layer 21) is connected 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 the layer 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 layer 12 laminated on the electrode layer 11, the heavy edge portion 16 is connected to the internal electrode layer 15, and one end 31 of the heavy edge portion 16 is exposed at the connection surface 30. When providing the 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.

[0015] 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 thereto. In order to provide a small, thin, and large-capacity capacitor, the dielectric layer 13 may be sufficiently thin and the main body 7 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 a 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 than that provided with a thermoplastic resin and can also cope with reflow, so it can be provided as a more suitable element for surface mounting.

[0016] 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 / □.

[0017] 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, with one end of the dummy heavy edge portion 17 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 the mechanical connection strength with the metallicon (metal spraying) 21 of the external electrode 20, and maintains or strengthens the connection with the metallicon 21 together with the heavy edge portion 16 integrated with the internal electrode layer 15. Therefore, hereinafter, the end of the dummy heavy edge portion 17 will also be described in common with the end 31 of the electrode layer 11 (dummy head portion 16). In this example, the layer 12 constituting the heavy edge portion 16 may be laminated on the upper side of the electrode layer 11, on the lower side, or on both the upper and lower sides. 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.

[0018] Making the electrode layer 11 into a thin film can increase the breakdown voltage, but the loss factor (tanδ) and the equivalent series resistance component (ESR) increase, and the performance of the capacitor is likely to deteriorate. Therefore, the configuration of the end (end portion) 31, which is the connection portion between the electrode layer 11 and the external electrode 20, is important. Conventionally, even if the internal electrode portion 15 is thin, it was considered that by ensuring sufficient thickness of the end portion 31, which is the connection portion with the external electrode 20, in this example, the metallicon 21, tanδ and ESR are reduced, the frequency characteristics are improved, and it becomes possible to handle high currents.

[0019] In laminated capacitors such as film capacitors and thin-film polymer multilayer capacitors, the method of connecting the laminate (body) 10 and the external electrode 20 is mostly metallization 21 within the commercialized range. At present, it is difficult to ensure the mechanical strength required for a capacitor by methods other than metallization, that is, metal spraying. In electrode extraction by metallization, in order to electrically bond the electrode layer 11 and the external electrode 20, while exposing the end (edge) 31 of the electrode, the inventors of the present application consider that it is necessary to create an uneven shape on the connection surface 30 that can obtain an anchor effect in order to obtain the bonding strength with the metallization 21. In the electrode extraction shape by the ashing method using plasma, which is currently the standard in thin-film polymer multilayer capacitors, it is considered difficult to obtain a stable uneven shape because it is greatly affected by the film formation state or the uneven distribution of the plasma. Therefore, in the current mass production process that only adopts the ashing method using plasma, the inventors of the present application assume that it is difficult to solve problems such as metallization peeling and poor electrical characteristics.

[0020] In the plasma treatment (ashing method) using oxygen plasma, it is considered that an uneven shape is realized by utilizing the variation in the adhesion force of each layer with respect to the energy of the plasma. That is, since the layer with weak adhesion is easily peeled off, the ashing progresses deeply, and it is considered that the uneven shape is formed because the ashing does not progress much in the strong layer. Therefore, the uneven shape formed by ashing strongly depends on the film formation state of each layer, and the more uniform the adhesion force of each layer is, the more difficult it becomes to obtain an uneven shape.

[0021] Figure 3 shows an outline of the assumed ashing mechanism. Ashing is originally a technique for uniformly etching organic substances. Therefore, a high ashing rate and a certain amount of ashing time are required to form unevenness. On the other hand, the thicker the dielectric thickness, the more likely it is to have a smooth ashing surface, and there is not much change in output and flow rate changes. Therefore, the factor for forming unevenness by ashing is considered to be to utilize the energy by strong ashing to make the difference in interlayer adhesion apparent. For example, as shown in Fig. 3(a), even if the connection surface 30 in the initial state is flat, as shown in Fig. 3(b), when the end 33 of the dielectric layer 13 is ashed by ashing, and delamination occurs between the end 31 of the electrode layer 11, it has been clarified by the analysis of the bonding part with the metallicon by the inventors of the present application. This phenomenon is assumed to be because, as shown in Fig. 3(c), the end 33 of the dielectric layer 13 shrinks due to the ashing reaction by oxygen radicals or the heat of the plasma. As shown in Fig. 3(d), it is considered that the peeling layer 39 advances ashing as the surface touched by oxygen radicals increases, and unevenness is formed on the connection surface 30.

[0022] On the other hand, as shown in Fig. 3(e), if the energy of the plasma is insufficient or excessive to cause a difference in delamination, ashing proceeds uniformly, no unevenness is formed on the connection surface 30, and only the electrode layer 11 is exposed. For this reason, the bonding force between the dielectric layer 13 and the external electrode 20 cannot be obtained, and there is a possibility that the adhesion force for stably maintaining the external electrode 20 cannot be obtained.

[0023] As shown in Fig. 4, in the present invention, instead of or in addition to the plasma treatment, prior to the metallization (metal spraying), at least a part of the connection surface 30 where the ends 33 of the plurality of dielectric layers 13 and the ends 31 of the plurality of electrode layers 11, which are the objects of the metallization, are exposed is scanned with a laser beam (laser, laser beam). As shown in Fig. 4(a), the connection surface 30 of the main body 10 is scanned with the laser beam 51 emitted from the laser light source 50. Specifically, as will be described later, the surface cut in a strip (stick) shape from the laminate that is the base of the main body 10 is used as the connection surface 30 and scanned with the laser beam 51, and the connection surface 30 is laser-treated by irradiating the connection surface 30 with the laser beam 51. It is considered that the laser treatment introduces a spatial (two-dimensional or three-dimensional) periodic structural or shape change (difference) to the ends 31 of the plurality of electrode layers 11 and the ends 33 of the plurality of resin layers 13 exposed on the connection surface 30, contributing to the enhancement of the adhesion force with the external electrode 20 by the metallization.

[0024] The most significant contribution by the laser treatment is considered to be that the laser treatment can introduce periodic unevenness to the ends 31 of the plurality of electrode layers 11 and the ends 33 of the plurality of resin layers 13 exposed on the connection surface 30. Examples of the laser for the treatment include any one of a YVO4 laser (wavelength 1064 nm), a YAG laser (wavelength 1064 nm), a fiber laser (wavelength 1090 nm), a semiconductor laser (wavelength 650 - 905 nm), an excimer laser (wavelength 193 nm), and a CO2 laser (wavelength 10600 nm). Examples of the semiconductor laser include GaAs, GaAlAs, and GaInAs.

[0025] The laser beam 51 may be pulsed. Taking the YVO4 laser as an example, the output may be set to 3 - 30 W, the scan speed to 100 - 10000 mm / s, the pulse frequency to 1 - 200 kHz, and the scan pitch to 0.01 - 0.2 mm.

[0026] Fig. 5 shows the result of observing the state of the connection surface 30 scanned by the YVO4 laser 51 with an output of 10 W, a scanning speed of 1000 mm, a pulse frequency of 40 kHz, and a scanning pitch of 0.04 mm using an electron microscope. As the electron microscope, S-3000H manufactured by Hitachi, Ltd. (observation conditions: acceleration voltage 5 kV, working distance 15 mm) was used. Fig. 5(a) shows the position of the observation surface. As described above, the laser processing is performed on the strip-shaped main body (stick-shaped main body part) 10a before cutting it into chip shape. The observation surface A in Fig. 5(b) shows a cross-section along the stick-shaped main body part 10a of the connection surface 30, the observation surface B in Fig. 5(c) shows a cross-section perpendicular to the stick-shaped main body part 10a of the connection surface 30, and the observation surface C in Fig. 5(d) shows a plane along the stick-shaped main body part 10a of the connection surface 30. As can be seen from the states of these observation surfaces, continuous unevenness (macroscopic unevenness) 35 is formed on the connection surface 30 by scanning with the laser beam 51, and furthermore, it can be seen that microscopic unevenness 36 in which the end 31 of the electrode layer 11 has retreated from the end 33 of the dielectric layer 13 is formed.

[0027] Fig. 4(b) conceptually shows the state of the connection surface 30 scanned by the laser 51, also considering the observation results shown in Fig. 5. By scanning the connection surface 30 with the laser 51, it is considered that a certain amount of the electrode layer 11 can be forcibly melted and evaporated, and the dielectric layer 13 can also be melted and evaporated. Thereby, it is considered that macroscopic unevenness 35 can be formed (introduced) on the connection surface 30.

[0028] As shown in the enlarged view of FIG. 4(c), it is considered possible to selectively melt and evaporate the end 31 that appears on the connection surface 30 of the electrode layer 11 by scanning the connection surface 30 with the laser 51. As a result, it is considered possible to form a region 37 in which the end 31 of the electrode layer 11 retreats with respect to the end 33 of the dielectric layer 13 and the interlayer of the dielectric layer 13 opens. For this reason, it is considered possible to form (introduce) a uniform uneven shape (microscopic uneven shape) 36 between the end 33 of the dielectric layer 13 and the end 31 of the electrode layer 11. Further, since the end 31 of the electrode layer 11 is evaporated by the laser beam 51, it is considered possible to suppress the presence of exposed internal electrodes that become an obstacle when the metallicon, which is a problem in the ashing shown in FIG. 3(e), enters the unevenness (interlayer) 36. Due to these factors, in the region 37 where microscopic unevenness 36 with a size of, for example, about 5 to 200 nm in layer thickness level is formed between the layers, the metallicon 21 can uniformly enter the microscopic unevenness 36, and it is considered that sufficient bonding strength and good electrical characteristics can be obtained even with a relatively shallow penetration amount.

[0029] Furthermore, by the scanning of the laser beam 51, both the end 33 of the dielectric layer 13 and the end 31 of the electrode layer 11 are melted and evaporated together, so that macroscopic unevenness 35 with a size larger than the layer thickness level, for example, about 200 nm to 100 μm, is formed. It is considered possible to suppress peeling due to stress that may occur between the metallicon 21 and the connection surface 30 by this macroscopic unevenness 35. For this reason, it is possible to manufacture the capacitor 1 having the metallicon 21 with sufficient bonding strength and good electrical characteristics with respect to the main body 10. The macroscopic unevenness 35 may be formed, for example, as distinct three-dimensional (3D) scanning marks 55 at a limited location on the connection surface 30 by narrowing the spot diameter of the laser beam 51 as shown in FIG. 4(d). Further, since it is considered possible to form a region 37 in which microscopic unevenness 36 is formed in the concave portion of the macroscopic unevenness 35, by forming three-dimensional scanning marks 55 on the connection surface 30 by laser processing, a region 37 in which microscopic unevenness 36 is formed can be formed on at least a part of the connection surface 30.

[0030] In FIG. 4, in order to schematically explain the outline of the laser processing, the main body portion 10 in which the thickness of the end 31 of the electrode layer 11 has no change is shown as an example. It is considered that the same applies to the laser processing of the connection surface 30 even when the end 31 of the thick film heavy edge portion 16 is exposed on the connection surface 30 with respect to the thin film internal electrode layer 15.

[0031] FIG. 6 shows a specific example of the laser processing. When irradiating the connection surface 30 with the laser beam 51, as shown in FIGS. 6(a) and (c), the spot diameter can be increased by defocusing (shifting the focus). On the other hand, as shown in FIG. 6(b), it is also possible to reduce the spot diameter by focusing the laser beam 51 on the connection surface 30. By scanning the connection surface 30 with the defocused laser beam 51, the processing speed by the laser beam can be improved, and depending on the energy distribution of the defocused laser beam 51, the scanning direction or interval, the connection surface 30 may be scanned with the laser beam 51 with a relatively large scanning mark or in a state where the scanning mark does not clearly appear. On the other hand, by scanning the connection surface 30 with the focused laser beam 51, a clear scanning mark by the laser beam 51 may be formed on the connection surface 30.

[0032] FIG. 7 shows some examples of the scanning traces 55 of the laser beam 51 formed on the connection surface 30. FIGS. 7(a) to (c) show examples of the scanning traces 55 composed of only diagonal patterns formed parallel or substantially parallel. FIGS. 7(d) to (f) show examples of the scanning traces 55 composed of patterns in which a plurality of lines intersect. The angles are shown with reference to the direction in which the end 33 of the dielectric layer 13 and the end 31 of the electrode layer 11 appearing on the connection surface 30 extend. The scanning traces 55 shown in FIG. 7 are merely examples, and the scanning traces formed by the laser beam 51 are not limited to these examples. Conditions such as the spot diameter of the laser beam 51 scanning the connection surface 30 and the pattern (scanning trace) can be selected according to conditions such as the processing time required for the processing of the laser beam 51 and the adhesion to the metallicon 21. Also, the connection surface 30 may be scanned in parallel by a plurality of laser beams 51. Regardless of the presence or absence of the scanning trace, by irradiating the connection surface 30 where the metallicon 21 is to be joined with the laser beam 51, the electrode layer 11 is selectively melted and evaporated in a certain amount, and each layer becomes uniformly separated. As a result, the metallicon 21 can uniformly enter between the layers. For this reason, a sufficient anchor effect and good electrical characteristics can be obtained.

[0033] FIG. 8 shows the main parts of a series of processes for manufacturing the capacitor 1 in a flowchart. In this manufacturing method 40, in step 41, a laminate serving as the base body of the main body 10 is manufactured. An example of a method for manufacturing the laminate is a method of forming each layer by vapor deposition. A device for manufacturing a laminate, which is the base body of the main body 10 in which a plurality of dielectric layers 13 and a plurality of electrode layers 11 are alternately laminated, by alternately forming the dielectric layer 13 and the electrode layer 11 by vapor deposition on a drum rotating in a reduced-pressure environment (vacuum environment) in a vacuum chamber, is known. The laminate may be manufactured using other methods such as coating or printing.

[0034] In step 42, the laminate is cut into strips to form the main body 10a in a strip state (stick state). The main body 10a in a strip state may be directly formed from the laminate, or the main body 10a in a strip state may be manufactured with other processes such as a planarization press process and a card cutting process interposed therebetween.

[0035] In step 43, a process is performed in which the strip-cut surface is scanned with a laser beam 51 as a connection surface 30 to be metallized. In this step 43, the spot of the laser beam 51 may be narrowed to form a scanning mark 55 by the laser beam 51 on the connection surface 30. Further, in this step 43, by irradiating the connection surface 30 with the laser beam 51, a portion (microscopic unevenness) 36 in which the ends 31 of the plurality of electrode layers 11 have each retreated with respect to the ends 33 of the plurality of dielectric layers 13 exposed on the connection surface 30 is formed in at least a part of the connection surface 30. Further, when each of the plurality of electrode layers 11 is connected to an internal electrode layer 15 of a thin film laminated inside the main body 10, one is exposed on the connection surface 30, and a thick-film heavy edge portion 16 is provided with respect to the internal electrode layer 15, the plurality of heavy edge portions 16 and the plurality of dielectric layers 13 appearing on the connection surface 30 may be scanned with the laser beam 51. The ends 31 of the heavy edge portions 16 having a film thickness with respect to the internal electrode layer 15 can be melted and evaporated by laser irradiation, and relatively large unevenness 36 can be formed between the adjacent dielectric layers 13 corresponding to the respective heavy edge portions 16. Therefore, the metallization 21 can enter more evenly, and a metallization 21 having sufficient bonding strength and good electrical characteristics can be manufactured. When a dummy heavy edge portion 17 is provided, the dummy heavy edge portion 17 can be similarly laser-processed, and the adhesion between the contact surface 30 including the dummy heavy edge portion 17 and the external electrode 20 can be improved.

[0036] Furthermore, in this step 43, by scanning the contact surface 30 with the laser beam 51, a scanning mark 55 by the laser beam 51 may be formed on the contact surface 30. The scanning mark 55 may be a three-dimensional scanning mark 55, and macroscopic unevenness 35 can be introduced into the contact surface 30. Further, since the bottom (concave portion) of the macroscopic unevenness 35 becomes a region 37 where microscopic unevenness 36 is formed, microscopic unevenness 36 can be formed in at least a part of the region 37 of the contact surface 30 in this step 43.

[0037] In step 44, an external electrode 20 is formed on the connection surface 30 scanned by the laser beam 51 by metallization (metal spraying). Examples of suitable metallization metals include zinc, tin, brass, and the like. Thereafter, processes required for the external electrode 20, such as heat treatment (step 45) and deburring (step 46), are performed. Further, in step 47, the capacitor 1 in which the external electrode 20 is connected to the main body portion 10 is manufactured by cutting the strip-shaped main body portion 10a on which the external electrode 20 is formed into a chip shape together with the external electrode 20. Note that the process described in FIG. 8 shows a typical process, and other processes may be performed. For example, a process such as plating may be appropriately performed between step 46 and step 47.

[0038] In this manufacturing method, before and after the process of scanning with the laser beam (step 43), a plasma process similar to the conventional one may be performed to control the state of the connection surface 30. On the other hand, when the external electrode 20 having sufficient bonding strength and good electrical characteristics can be manufactured by the process of scanning with the laser beam (step 43) and the plasma process can be omitted, the processes after the strip cutting can be performed in the air. Therefore, the manufacturing process of the capacitor can be further simplified. Accordingly, a capacitor 1 having a main body portion 10 in which a plurality of dielectric layers 13 and a plurality of electrode layers 11 are laminated and an external electrode 20 connected to at least a part of the main body portion 10 can be provided at a lower cost.

[0039] The capacitor 1 manufactured by this manufacturing method may include scanning traces 55 by laser light 51 on at least a part of the connection surface 30 of the main body 10 where the external electrode 20 is formed by the metallicon 21. In the capacitor 1 in which the electrode layer 11 has a thick-film heavy edge portion 16 with respect to the internal electrode layer 15, the connection surface 30 may include scanning traces 55 extending over the plurality of heavy edge portions 16 and the plurality of dielectric layers 13 appearing on the connection surface 30. Further, the capacitor 1 manufactured by this manufacturing method may include a region 37 in which unevenness 36 is formed in which at least a part of the ends 31 of the plurality of electrode layers 11 or the heavy edge portions 16 recedes with respect to at least a part of the ends 33 of the plurality of dielectric layers 13 on at least a part of the connection surface 30 of the main body 10.

[0040] Also, 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 method for manufacturing a capacitor having a main body portion in which a plurality of dielectric layers and a plurality of electrode layers are alternately laminated, and an external electrode connected to at least a part of the main body portion, the method including scanning at least a part of a connection surface of the main body portion, which is a connection surface of the main body portion to be subjected to metal spraying and at which ends of the plurality of dielectric layers and the plurality of electrode layers are exposed, with laser light before forming the external electrode on the main body portion by metal spraying.

2. In Claim 1, the scanning includes forming a scanning mark by the laser light on the connection surface.

3. In Claim 1, the scanning includes forming a three-dimensional scanning mark by the laser light on the connection surface.

4. In Claim 1, the scanning includes forming unevenness on at least a part of the connection surface.

5. In any one of Claims 1 to 4, the scanning includes forming a region in which at least a part of the ends of the plurality of electrode layers recedes with respect to at least a part of the ends of the plurality of dielectric layers exposed on the connection surface on at least a part of the connection surface.

6. In any one of Claims 1 to 4, each of the plurality of electrode layers is connected to an internal electrode layer laminated inside the main body portion, and has a thick film heavy edge portion with respect to the internal electrode layer, with one end exposed on the connection surface, the scanning includes scanning at least a part of the ends of the plurality of heavy edge portions and at least a part of the ends of the plurality of dielectric layers appearing on the connection surface with the laser light.

7. In any one of Claims 1 to 4, the scanning includes scanning with at least any one of a YVO4 laser, a YAG laser, a fiber laser, a semiconductor laser, an excimer laser, and a CO2 laser.

8. In any one of Claims 1 to 4, manufacturing a laminate by alternately forming and laminating the plurality of dielectric layers and the plurality of electrode layers, forming the main body portion in a strip state obtained by strip cutting from the laminate, the scanning includes scanning the strip-cut surface as the connection surface with the laser light, and further, the manufacturing method is as follows. forming the external electrode by metal spraying on the connection surface scanned by the laser light; A manufacturing method, comprising cutting the strip-shaped main body part on which the external electrode is formed into a chip shape together with the external electrode. **Claim 9** A capacitor having a main body part in which a plurality of dielectric layers and a plurality of electrode layers are alternately laminated, and an external electrode connected to at least a part of the main body part, A capacitor, wherein at least a part of the connection surface of the main body part on which the external electrode is formed by metal spraying includes scanning marks by laser light. **Claim 10** In Claim 9, each of the plurality of electrode layers is connected to an internal electrode layer laminated inside the main body part, and has a thick film heavy edge part with respect to the internal electrode layer, with one end exposed on the connection surface; A capacitor, wherein the connection surface includes the scanning marks extending at least partially over the ends of the plurality of heavy edge parts appearing on the connection surface and the ends of the plurality of dielectric layers.

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