Capacitor and method for manufacturing 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

Capacitor and manufacturing method thereof

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

[0002] In Japanese Patent Application Laid-Open No. 2004-6495, a laminated substrate is formed by depositing aluminum on dielectric resin layers and stacking them alternately, and then the laminated substrate is cut into sticks. ３ , C.F. ４ , O ２ The present invention discloses a laminated metallized film capacitor and a method for manufacturing the same, which are characterized in that a mixed gas containing two or more of the above is activated to form a plasma state, the cut surface is subjected to a chemical dry etching treatment to an etching depth of 10 to 100 μm, and the etched surface is subjected to metal spraying to form an electrode lead portion.

[0003] Multilayer capacitors are available in compact sizes with high withstand voltages and low ESR. Furthermore, it is important to ensure good and stable connectivity with external electrodes, resulting in good withstand voltage characteristics. For example, compared to film capacitors, thin-film polymer multilayer capacitors can have dielectric layers as thin as 1.5 μm or less, enabling the provision of compact capacitors with high withstand voltages and low ESR. On the other hand, if the surface resistivity (sheet resistivity) of the capacitor's electrode portions (internal electrode portions) is thinned to a sufficient degree to increase the withstand voltage, the connection portions with the external electrodes also become thin. This increases the connection resistance of the connection portions, making it difficult to sufficiently reduce ESR. The adoption of a heavy-edge structure, in which only the edge portions are thicker, is also being considered. To provide capacitors with compact sizes, high withstand voltages, and even lower connection resistance, it is important to further stabilize the connection with the external electrodes.

[0004] One aspect of the present invention is a method for manufacturing a capacitor having a body portion formed by alternating multiple dielectric layers and multiple electrode layers and an external electrode connected to at least a portion of the body portion. This manufacturing method includes, before forming the external electrode on the body portion by metal spraying, scanning with a laser beam at least a portion of the connection surface of the body portion to be metal sprayed, the connection surface having the exposed ends of the multiple dielectric layers and multiple electrode layers. Scanning the connection surface with a laser beam (scanning step, scanning process) may be used instead of or in addition to plasma surface treatment. By irradiating the connection surface with a laser beam, the connection surface can be processed so that changes in the structure and / or shape of at least a portion of the connection surface are repeated at appropriate intervals (pitch). For example, to ensure stable connection with the external electrode formed by metal spraying, a stable uneven shape may be formed on the connection surface. Compared to laser beam treatment, plasma treatment essentially ashes the dielectric layer, and the amount of ashing depends on the film formation state of the dielectric layer. Furthermore, uneven plasma distribution can easily cause variations in the processing amount. Therefore, it is difficult to control the state of the electrode layer at the connection surface by plasma treatment or only by plasma treatment. In the present invention, the connection surface is scanned with a laser beam. This method makes it possible to forcibly melt and evaporate not only the edge of the dielectric layer but also the edge of the electrode layer, and thus to introduce a structure or shape at the connection surface that is more stable and has high connectivity with the metal spray, periodically in two or three dimensions.

[0005] The process (process, step) of scanning with laser light may include forming a scanning mark by the 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 portion of the connection surface. As one example, scanning the connection surface with a laser light having a relatively large spot diameter may form irregularities due to the film formation state of the dielectric layer and / or electrode layer. As another example, scanning with a laser light having a relatively small spot diameter may form scanning marks with irregularities in a predetermined direction or shape, and may forcibly form irregularities of a predetermined shape on the connection surface.

[0006] The scanning process may include forming, on at least a portion of the connection surface, an area in which at least a portion of the ends of the plurality of electrode layers is recessed relative to at least a portion of the ends of the plurality of dielectric layers exposed on the connection surface. The electrode layer formed of a metal such as aluminum may be more easily evaporated by laser irradiation than the dielectric layer, and a concave-convex structure having high connectivity with the metal spray may be formed by causing the ends of the electrode layer to recess relative to the ends of the dielectric layer by laser irradiation.

[0007] Each of the plurality of electrode layers may be connected to an internal electrode layer stacked inside the main body, and may have a thicker heavy edge portion with one end exposed on the connection surface than the internal electrode layer. The scanning process may include scanning the ends of the plurality of heavy edge portions and the ends of the plurality of dielectric layers with a laser beam. If the electrode layer exposed on the connection surface becomes too thick, connectivity with the external electrode is likely to decrease. However, by irradiating the laser beam to create stable unevenness, this decrease in connectivity can be suppressed. Furthermore, by irradiating the laser beam to the thicker heavy edge portion, the unevenness between the dielectric layer and the electrode layer tends to increase, thereby improving connectivity with the external electrode.

[0008] The laser light used in the scanning process may be at least one of a YVO4 laser, a YAG laser, a fiber laser, a semiconductor laser, an excimer laser, and a CO2 laser.

[0009] This manufacturing method may further include the following steps: - Manufacturing a laminate by alternately depositing multiple dielectric layers and multiple electrode layers; - Forming a main body portion in a strip state (stick state) by cutting the laminate into strips; - Scanning the cut strip surface with a laser beam as a connecting surface; - Forming external electrodes by metal spraying on the connecting surface scanned with the laser beam; - Cutting the main body portion in a strip state with the external electrodes formed thereon into chips together with the external electrodes. If the plasma treatment can be omitted by using the laser beam scanning treatment, the treatments from strip cutting onwards can be performed in the atmosphere, further simplifying the capacitor manufacturing process. This allows capacitors to be provided at even lower cost.

[0010] Another aspect of the present invention is a capacitor having a body portion formed by stacking multiple dielectric layers and multiple electrode layers, and an external electrode connected to at least a portion of the body portion. At least a portion of the connection surface of the body portion of this capacitor, on which the external electrode is formed by metal spraying, includes a scanning mark created by laser light. The multiple electrode layers may be connected to an internal electrode layer stacked inside the body portion, one end of which is exposed on the connection surface, and may have a thick heavy edge portion relative to the internal electrode layer. The connection surface may include a scanning mark that extends from the ends of the multiple heavy edge portions exposed on the connection surface to the ends of the multiple dielectric layers.

[0011] Another aspect of the present invention is a capacitor having a body portion formed by stacking multiple dielectric layers and multiple electrode layers, and an external electrode connected to at least a portion of the body portion, wherein at least a portion of the connection surface of the body portion on which the external electrode is formed by metal spraying includes irregularities where at least a portion of the edges of the multiple electrode layers are recessed relative to a portion of the edges of the multiple dielectric layers. Each of the multiple electrode layers of this capacitor may be connected to an internal electrode layer stacked inside the body portion, one end exposed on the connection surface, and have a thick heavy edge portion relative to the internal electrode layer, and at least a portion of the edges of the multiple heavy edge portions exposed on the connection surface may be recessed relative to a portion of the edges of the multiple dielectric layers.

[0012] FIG. 1 is a diagram showing an outline of a capacitor. FIG. 2 is a cross-sectional view showing an outline of an active layer (laminated body). FIG. 3 is a diagram showing an outline of plasma processing. FIG. 4 is a diagram showing an outline of processing using laser light. FIG. 5 is a diagram showing an example of processing using laser light. FIG. 6 is a diagram showing the state of a laser light spot. FIG. 7 is a diagram showing an example of a scanning mark of laser light. FIG. 8 is a flowchart showing an example of a method for manufacturing a capacitor. MODE FOR CARRYING OUT THE INVENTION

[0013] FIG. 1 shows an example of a capacitor according to the present invention. A thin-film polymer multilayer capacitor is known as a capacitor 1 having a main body (main body, laminate) 10 formed by alternately stacking multiple dielectric layers and multiple electrode layers, and external electrodes 20 connected to the main body 10. The capacitor 1 shown in FIG. 1( a) is an example of a thin-film polymer multilayer capacitor. 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 protective layers 9 that are located above and below the active layer 7. The active layer 7 and dummy layers 8 are configured by alternately stacking multiple resin layers (dielectric layers) 13 and multiple electrode layers 11, and the protective layers 9 are made of resin only. The external electrode 20 is formed by metal spraying (metallikon) so as to join to the connection surface 30 where the ends of the multiple electrode layers 11 of the active layer 7 and the dummy layer 8 and the ends of the multiple resin layers 13 appear, and includes an inner metallikon layer (metal sprayed layer, for example, brass metallikon) 21, a copper plating layer 22 covering the periphery thereof, and a tin plating layer 23 covering the outside.

[0014] 2 shows an enlarged cross section of a portion of the active layer 7 of the main body 10. The active layer 7 of the main body 10 is a portion in which multiple dielectric layers 13 and multiple electrode layers 11 are alternately stacked. Ideally, at the connection surface 30, an end (end, edge, connection portion, connection region, connection boundary) 31 of each electrode layer 11 and an end 33 of each dielectric layer 13 are joined to the metallikon layer 21 of the external electrode 20, and each electrode layer 11 is also electrically connected to the metallikon 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 and forms a capacitance, and a heavy edge portion 16 whose end 31 where the external electrode 20 (metallikon 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 a layer 12 stacked 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 electrode layer 11 and the laminated layer 12, 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. To provide a capacitor 1 with a high withstand voltage, the thickness of the internal electrode layer (internal electrode portion) 15 is desirably thin, for example, 0.01 μm or even thinner, 0.005 μm (5 nm). However, considering the connection with the external electrode 20, a thickness of approximately 0.01 μm or more is considered necessary, and a capacitor 1 having a thin-film type internal electrode portion 15 may have the heavy edge portion 16. Note that if 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, including an acrylic polymer. An example of a resin that can be used in the thin-film polymer multilayer capacitor 1 is a polymerized version of one or more of tricyclodecane dimethanol dimethacrylate or tricyclodecane dimethanol diacrylate, but the resin constituting the dielectric layer 13 is not limited to these. To provide a small, thin, and high-capacity capacitor, the dielectric layer 13 may be sufficiently thin and the main body 7 may have a sufficient number of layers. For example, the thickness of the dielectric layer 13 may be 0.1 to 1.5 μm or 0.2 to 1.2 μm, and the number of layers may be 1,000 or more. The thin-film dielectric layer 13 can be formed by depositing a thermosetting resin as a monomer under a reduced pressure (vacuum) and curing it by irradiation with an electron beam or the like, thereby achieving a dielectric layer 13 of a predetermined thickness. Capacitors 1 with a dielectric layer 13 made of a thermosetting resin have a higher heat resistance temperature and are reflow-compatible compared to those with a thermoplastic resin, making them more suitable for surface mounting.

[0016] The electrode layer 11 may be formed of at least one conductive metal, such as aluminum, zinc, copper, gold, silver, or an alloy containing any of these. For a high-voltage capacitor 1, the withstand voltage can be improved by reducing the thickness of the electrodes that function as a capacitor, i.e., the internal electrode layers 15. For example, the withstand voltage may be 400 V or more, and the thickness of the internal electrode layers 15 may be approximately 3 to 50 nm, or approximately 5 to 30 nm. The thickness of the thin-film electrodes may be controlled using surface resistivity, and the surface resistivity of the internal electrode layers 15 may be 5 to 80 Ω / □ (Ω / sq.), 15 to 60 Ω / □, or 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 at the connection surface 30. Because 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 metallikon (metal spray coating) 21 of the external electrode 20, and together with the heavy edge portion 16 integrated with the internal electrode layer 15, it maintains or strengthens the connection with the metallikon 21. Therefore, hereinafter, the end of the dummy heavy edge portion 17 will be treated as the end 31 of the electrode layer 11 (dummy hedge portion 16) in the following description. In this example, the layer 12 constituting the heavy edge portion 16 may be laminated above or below the electrode layer 11, or may be laminated on both the top and bottom surfaces. The heavy edge portion 16 is not limited to a two-layer structure, but may also be a single-layer structure or a three- or more-layer structure.

[0018] Making the electrode layer 11 thin can increase the withstand voltage, but it also increases the loss factor (tan δ) and equivalent series resistance (ESR), which tends to reduce the performance of the capacitor. For this reason, 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, it was thought that even if the internal electrode portion 15 was thin, by ensuring a sufficient thickness of the end portion 31, which is the connection portion with the external electrode 20, in this example, the metallikon 21, it would be possible to reduce tan δ and ESR, improve frequency characteristics, and enable the capacitor to handle high currents.

[0019] In multilayer capacitors, such as film capacitors and thin-film polymer multilayer capacitors, metallicon 21 is the most commonly used method for connecting the laminate (main body) 10 and the external electrode 20. Currently, it is difficult to ensure the mechanical strength required for a capacitor using methods other than metallicon, i.e., metal spraying. The inventors believe that when using metallicon to connect the electrode layer 11 and the external electrode 20, it is necessary to expose the electrode end (end) 31 and create a textured surface 30 that provides an anchoring effect to ensure the bonding strength with the metallicon 21. The electrode shape created by the plasma ashing method, currently the standard for thin-film polymer multilayer capacitors, is difficult to achieve because it is significantly affected by the film formation state and uneven plasma distribution. Therefore, the inventors believe that it is difficult to solve problems such as metallicon peeling and poor electrical characteristics in the current mass production process that exclusively uses plasma ashing.

[0020] In plasma treatment (ashing) using oxygen plasma, it is thought that the unevenness is achieved by taking advantage of the variation in the adhesion strength of each layer relative to the plasma energy. That is, layers with weak adhesion are easily peeled off, so ashing proceeds deeply, while layers with strong adhesion are not ashed very far, resulting in the formation of the unevenness. For this reason, the unevenness formed by ashing is strongly dependent on the film formation state of each layer, and the more uniform the adhesion strength of each layer, the more difficult it is to obtain an unevenness.

[0021] Figure 3 shows an overview of the assumed ashing mechanism. Ashing is originally a technique for uniformly etching organic materials. Therefore, a high ashing rate and a certain amount of ashing time are required to form irregularities. On the other hand, the thicker the dielectric, the smoother the ashed surface tends to be, and changes in power and flow rate do not significantly affect this. Therefore, the cause of irregularities formed by ashing is thought to be the use of strong ashing energy to expose differences in interlayer adhesion. For example, even if the initial connection surface 30 is flat as shown in Figure 3(a), the inventors of the present application have revealed that ashing ashes the end 33 of the dielectric layer 13 and causes delamination between the end 31 of the electrode layer 11 and the end 31, as shown in Figure 3(b). This phenomenon is thought to be due to the shrinkage of the end 33 of the dielectric layer 13 due to the ashing reaction caused by oxygen radicals and the heat of the plasma, as shown in Figure 3(c). As shown in FIG. 3D, it is believed that the surface area of ​​the peeling layer 39 that comes into contact with oxygen radicals increases, which causes ashing to progress and causes unevenness to form on the connection surface 30.

[0022] 3( e), if the plasma energy is insufficient or excessive to cause a difference in delamination between the layers, ashing will proceed uniformly, no irregularities will be formed on the connection surface 30, and only the electrode layer 11 will be exposed. As a result, the bonding strength between the dielectric layer 13 and the external electrode 20 will not be sufficient, and there is a possibility that the adhesive strength required to stably maintain the external electrode 20 will not be sufficient.

[0023] As shown in Fig. 4 , in the present invention, instead of or in addition to plasma treatment, prior to metallikon (metal spraying), a process of scanning at least a portion 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 targets of metallikon, are exposed, with laser light (laser, laser beam). As shown in Fig. 4(a) , the connection surface 30 of the main body 10 is scanned with laser light 51 emitted from a laser light source 50. Specifically, as described below, a strip-shaped (stick-shaped) surface cut from the laminate that forms the base of the main body 10 is scanned with laser light 51 as the connection surface 30, and the connection surface 30 is laser-treated by irradiating the laser light 51. The laser treatment introduces spatially (two-dimensionally or three-dimensionally) periodic structural or morphological changes (differences) into the ends 31 of the plurality of electrode layers 11 and the ends 33 of the plurality of resin layers 13, which are exposed on the connection surface 30, and is thought to contribute to strengthening the adhesion of the metallikon to the external electrode 20.

[0024] The greatest contribution of the laser treatment is believed to be the introduction of periodic irregularities to the edges 31 of the electrode layers 11 and the edges 33 of the resin layers 13 exposed on the connection surface 30. Examples of lasers used for the treatment include a YVO4 laser (wavelength 1064 nm), a YAG laser (wavelength 1064 nm), a fiber laser (wavelength 1090 nm), a semiconductor laser (wavelength 650 to 905 nm), an excimer laser (wavelength 193 nm), and a CO2 laser (wavelength 10600 nm). Examples of semiconductor lasers include GaAs, GaAlAs, and GaInAs.

[0025] The laser light 51 may be pulsed, and in the case of a YVO4 laser, the output may be set to 3 to 30 W, the scanning speed to 100 to 10,000 mm / s, the pulse frequency to 1 to 200 kHz, and the scanning pitch to 0.01 to 0.2 mm.

[0026] FIG. 5 shows the results of electron microscope observation of the state of the connection surface 30 scanned with a YVO4 laser 51 with an output of 10 W, a scan speed of 1000 mm, a pulse frequency of 40 kHz, and a scan pitch of 0.04 mm. The electron microscope used was a Hitachi S-3000H (observation conditions: acceleration voltage 5 kV, working distance 15 mm). FIG. 5(a) shows the position of the observation surface. As described above, laser processing was performed on the strip-like main body (stick-shaped main body portion) 10a before cutting into chips. Observation surface A in FIG. 5(b) shows a cross section along the stick-shaped main body portion 10a of the connection surface 30. Observation surface B in FIG. 5(c) shows a cross section perpendicular to the stick-shaped main body portion 10a of the connection surface 30. Observation surface C in FIG. 5(d) shows a plane along the stick-shaped main body portion 10a of the connection surface 30. As can be seen from the state of these observed surfaces, continuous irregularities (macroscopic irregularities) 35 are formed on the connection surface 30 by scanning with the laser light 51, and further, microscopic irregularities 36 are formed in which the end 31 of the electrode layer 11 is recessed from the end 33 of the dielectric layer 13.

[0027] 4(b) conceptually shows the state of the connection surface 30 scanned by the laser 51, taking into consideration the observation results shown in Fig. 5. It is believed that scanning the connection surface 30 with the laser 51 forcibly melts and evaporates a certain amount of the electrode layer 11, and also melts and evaporates the dielectric layer 13. This is believed to allow macroscopic irregularities 35 to be formed (introduced) on the connection surface 30.

[0028] As shown enlarged in FIG. 4( c), scanning the connection surface 30 with a laser 51 may further selectively melt and evaporate the edge 31 of the electrode layer 11 that appears on the connection surface 30. This may cause the edge 31 of the electrode layer 11 to recede relative to the edge 33 of the dielectric layer 13, forming an open region 37 between the dielectric layer 13. This may allow a uniform uneven shape (microscopic uneven shape) 36 to be formed (introduced) between the edge 33 of the dielectric layer 13 and the edge 31 of the electrode layer 11. Furthermore, because the edge 31 of the electrode layer 11 is evaporated by the laser beam 51, it may be possible to suppress the presence of exposed internal electrodes that would hinder the metallikon from penetrating into the unevenness (between layers) 36, which is a problem with ashing such as that shown in FIG. 3( e). Due to these factors, in the region 37 where microscopic irregularities 36 of a size on the order of the layer thickness, for example, 5 to 200 nm, are formed between the layers, the metallikon 21 can penetrate evenly into the microscopic irregularities 36, and it is thought that sufficient bonding strength and good electrical characteristics can be obtained even with a relatively shallow penetration.

[0029] Furthermore, by scanning with the laser light 51, both the edge 33 of the dielectric layer 13 and the edge 31 of the electrode layer 11 are melted and evaporated, forming macroscopic irregularities 35 having a size greater than the layer thickness level, for example, approximately 200 nm to 100 μm. It is believed that these macroscopic irregularities 35 make it possible to suppress peeling due to stress that may occur between the metallikon 21 and the connection surface 30. This makes it possible to manufacture a capacitor 1 having a metallikon 21 that has sufficient bonding strength to the main body 10 and good electrical characteristics. The macroscopic irregularities 35 may be formed so as to be clearly visible as three-dimensional scanning marks 55 in a limited location on the connection surface 30 by narrowing the spot diameter of the laser light 51, as shown in FIG. 4( d ), for example. Furthermore, since it is believed that an area 37 in which microscopic irregularities 36 are formed can be formed in the recesses of the macroscopic irregularities 35, by forming three-dimensional scanning marks 55 on the connection surface 30 by laser processing, an area 37 in which microscopic irregularities 36 are formed can be formed on at least a part of the connection surface 30.

[0030] 4, in order to provide a schematic overview of the laser treatment, the main body 10 is shown as an example in which the thickness of the end 31 of the electrode layer 11 does not change. The laser treatment of the connection surface 30 is considered to be similar even when the end 31 of the thick heavy edge portion 16 is exposed on the connection surface 30 in comparison with the thin internal electrode layer 15.

[0031] FIG. 6 shows a specific example of laser processing. When irradiating the connection surface 30 with laser light 51, the spot diameter can be increased by defocusing (shifting the focus), as shown in FIGS. 6( a) and 6(c). On the other hand, as shown in FIG. 6(b), the spot diameter can also be reduced by focusing the laser light 51 on the connection surface 30. By scanning the connection surface 30 with defocused laser light 51, the processing speed using the laser light can be improved. Depending on the energy distribution, scanning direction, or spacing of the defocused laser light 51, the connection surface 30 may be scanned with the laser light 51 with relatively large scanning marks or with scan marks that are not clearly visible. On the other hand, by scanning the connection surface 30 with focused laser light 51, clear scanning marks caused by the laser light 51 may be formed on the connection surface 30.

[0032] FIG. 7 shows several examples of scanning marks 55 formed on the connection surface 30 by the laser beam 51. FIGS. 7( a ) to 7 ( c ) show examples of scanning marks 55 consisting of a pattern of only parallel or nearly parallel diagonal lines. FIGS. 7( d ) to 7 ( f ) show examples of scanning marks 55 consisting of a pattern of multiple intersecting lines. The angles are shown based on the direction of extension of the edge 33 of the dielectric layer 13 and the edge 31 of the electrode layer 11 that appear on the connection surface 30. The scanning marks 55 shown in FIG. 7 are merely examples, and the scanning marks formed by the laser beam 51 are not limited to these examples. The conditions for the spot diameter and pattern (scanning marks) of the laser beam 51 scanning the connection surface 30 can be selected based on the processing time required for the laser beam 51 processing, the adhesion to the metallikon 21, and other conditions. Furthermore, the connection surface 30 may be scanned in parallel with multiple laser beams 51. Regardless of whether or not there are scanning marks, by irradiating the connection surface 30 to which the metallikon 21 is to be joined with laser light 51, a certain amount of the electrode layer 11 is selectively melted and evaporated, and each layer is uniformly separated. This allows the metallikon 21 to penetrate evenly between each layer. As a result, a sufficient anchor effect and good electrical properties are obtained.

[0033] 8 is a flowchart showing the main steps of a series of steps for manufacturing capacitor 1. In this manufacturing method 40, in step 41, a laminate that serves as the base of main body 10 is manufactured. One example of a method for manufacturing the laminate is a method of forming each layer by vapor deposition. An apparatus is known that uses vapor deposition to alternately form dielectric layers 13 and electrode layers 11 on a drum that rotates in a reduced pressure environment (vacuum environment) in a vacuum chamber, thereby manufacturing a laminate that serves as the base of main body 10, in which multiple dielectric layers 13 and multiple electrode layers 11 are alternately stacked. The laminate may also 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 (stick state). The main body 10a in a strip state may be formed directly from the laminate, or the main body 10a in a strip state may be manufactured by performing other processes such as a flattening press process or a card cutting process.

[0035] In step 43, a process of scanning the strip-cut surface with a laser beam 51 as the connection surface 30 to be subjected to metallikon is performed. 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. Also, in this step 43, by irradiating the connection surface 30 with the laser beam 51, portions (microscopic irregularities) 36 in which the ends 31 of the plurality of electrode layers 11 are recessed from the ends 33 of the plurality of dielectric layers 13 exposed on the connection surface 30 are formed on at least a portion of the connection surface 30. Also, in the case where each of the plurality of electrode layers 11 is connected to a thin-film internal electrode layer 15 stacked inside the main body 10, one end of which is exposed on the connection surface 30 and has a heavy edge portion 16 that is thicker than the internal electrode layer 15, the plurality of heavy edge portions 16 appearing on the connection surface 30 and the plurality of dielectric layers 13 may be scanned with the laser beam 51. The edges 31 of the heavy edge portions 16 having a thickness relative to the internal electrode layer 15 can be melted and evaporated by laser irradiation, and relatively large irregularities 36 can be formed between the adjacent dielectric layers 13 corresponding to each heavy edge portion 16. This allows the metallikon 21 to penetrate more evenly, making it possible to manufacture metallikon 21 with sufficient bonding strength and good electrical properties. If dummy heavy edge portions 17 are provided, the dummy heavy edge portions 17 can also be laser-treated in the same way, improving the adhesion between the contact surface 30, including the dummy heavy edge portions 17, and the external electrode 20.

[0036] Furthermore, in step 43, the contact surface 30 may be scanned with laser light 51, thereby forming scanning marks 55 by the laser light 51 on the contact surface 30. The scanning marks 55 may be three-dimensional scanning marks 55, and macroscopic irregularities 35 can be introduced into the contact surface 30. Furthermore, the bottoms (concave portions) of the macroscopic irregularities 35 become the regions 37 where the microscopic irregularities 36 are formed, so in step 43, the microscopic irregularities 36 can be formed in at least a portion of the region 37 of the contact surface 30.

[0037] In step 44, the external electrodes 20 are formed by metallization (metal spraying) on ​​the connection surface 30 scanned by the laser beam 51. Examples of suitable metallization metals include zinc, tin, and brass. Subsequently, required processes for the external electrodes 20, such as heat treatment (step 45) and deburring (step 46), are performed. Furthermore, in step 47, the strip-like body portion 10a on which the external electrodes 20 are formed is cut into chips together with the external electrodes 20, thereby manufacturing a capacitor 1 in which the external electrodes 20 are connected to the body portion 10. Note that the steps shown in FIG. 8 are representative processes, and other processes may also be performed. For example, processes such as plating may be performed as appropriate between steps 46 and 47.

[0038] In this manufacturing method, a conventional plasma treatment may be performed before or after the laser scanning process (step 43) to control the state of the connection surface 30. On the other hand, if the laser scanning process (step 43) can produce an external electrode 20 with sufficient bonding strength and good electrical properties, and plasma treatment can be omitted, the processes from strip cutting onward can be performed in the atmosphere. This further simplifies the capacitor manufacturing process. Therefore, a capacitor 1 can be provided at even lower cost, having a body 10 formed by stacking multiple dielectric layers 13 and multiple electrode layers 11, and an external electrode 20 connected to at least a portion of the body 10.

[0039] The capacitor 1 manufactured by this manufacturing method may include a scanning mark 55 by the 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 of metallikon 21. In a capacitor 1 in which the electrode layer 11 has a heavy edge portion 16 that is thicker than the internal electrode layer 15, the connection surface 30 may include a scanning mark 55 that extends over the multiple heavy edge portions 16 that appear on the connection surface 30 and the multiple dielectric layers 13. The capacitor 1 manufactured by this manufacturing method may also include a region 37 in which irregularities 36 are formed, in which at least a part of the edges 31 of the multiple electrode layers 11 or the heavy edge portions 16 are recessed relative to at least a part of the edges 33 of the multiple dielectric layers 13, on at least a part of the connection surface 30 of the main body 10 where the external electrode 20 is formed of metallikon 21.

[0040] Furthermore, while 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. 1. A method for manufacturing a capacitor having a 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 portion of the body portion, comprising the steps of: a manufacturing method including, before forming the external electrode on the main body by metal spraying, scanning at least a portion of the connection surface of the main body that is to be metal sprayed, where ends of the plurality of dielectric layers and the plurality of electrode layers are exposed, with a laser light.

2. In claim 1, The scanning step 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 method of manufacturing, wherein the scanning includes forming irregularities on at least a portion of the connecting surface.

5. In any one of claims 1 to 4, The manufacturing method, wherein the scanning includes forming an area on at least a portion of the connection surface in which at least a portion of the ends of the plurality of electrode layers are recessed relative to at least a portion of the ends of the plurality of dielectric layers exposed on 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 includes a heavy edge portion that is thicker than the internal electrode layer and has one end exposed to the connection surface, The manufacturing method, wherein the scanning step includes scanning at least a portion of the ends of the plurality of heavy edge portions and the ends of the plurality of dielectric layers exposed on the connection surface with the laser light.

7. In any one of claims 1 to 4, The scanning step includes scanning with at least 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, forming the plurality of dielectric layers and the plurality of electrode layers alternately to produce a laminate; and forming the main body portion in a strip state by cutting the main body portion from the laminate. The scanning step includes scanning a cut surface as the connecting surface with the laser light, Furthermore, the manufacturing method includes: forming the external electrodes by metal spraying on the connection surfaces scanned by the laser light; cutting the strip-like body portion on which the external electrodes are formed into chips together with the external electrodes.

9. A capacitor having a 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 portion of the body portion, A capacitor comprising a scanning mark made by a laser beam on at least a part of a connection surface of the main body on which the external electrode is formed by metal spraying.

10. In claim 9, Each of the plurality of electrode layers is connected to an internal electrode layer laminated inside the main body portion, and includes a heavy edge portion that is thicker than the internal electrode layer and has one end exposed to the connection surface, The connection surface includes the scanning marks extending over at least a portion of edges of the heavy edge portions and the dielectric layers that are exposed on the connection surface.