Metal mask, method for forming internal electrode pattern of multilayer ceramic capacitor, method for forming internal electrodes of multilayer ceramic capacitor, method for manufacturing multilayer ceramic capacitor, and method for managing metal mask for forming internal electrodes of multilayer ceramic capacitor

Abstract

A metal mask is provided that allows for the formation of internal electrodes with good shapes and good electrical properties. [Solution] A metal mask for manufacturing internal electrodes of a multilayer ceramic capacitor has a metal substrate with a through hole formed therein that is rectangular in plan view. The dimension of the through portion of the through hole in the direction of the short side of the rectangle in plan view is 300 μm or less. In the cross-sectional shape of the peripheral edge facing the through portion, a step height is formed on one side in the thickness direction of the substrate, and a tapered portion extending in a direction away from the through portion is formed on the other side in the thickness direction. The dimension of the step height located in the direction of the short side in the thickness direction is 12.2 μm or less. The tapered portion located in the direction of the short side has a taper angle with respect to the short side direction of 47.0° or less.

Description

[Technical Field]

[0001] The present invention relates to a metal mask, a method for forming an internal electrode pattern of a multilayer ceramic capacitor, a method for forming internal electrodes of a multilayer ceramic capacitor, a method for manufacturing a multilayer ceramic capacitor, and a method for managing a metal mask for forming internal electrodes of a multilayer ceramic capacitor. [Background technology]

[0002] MLCCs are chip-type capacitors with multiple layers of internal electrodes and dielectric sheets (often called green sheets). While MLCCs are becoming increasingly smaller, they are still required to have sufficient capacitance as a capacitor. In order to increase capacitance without increasing size, it is necessary to reduce the thickness of the internal electrodes and increase the number of layers. Screen printing has traditionally been used to form the internal electrodes, but by using the sputtering method, it is possible to deposit thin films of the internal electrodes and increase the number of layers compared to conventional methods.

[0003] One method for producing metal masks used in sputtering, vapor deposition, etc. is to wet-etch a thin metal substrate (see, for example, Patent Document 1). Material flying from the target passes through through holes formed by etching, and is deposited at a predetermined position with predetermined dimensions and shape. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5382259 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned sputtering deposition, the deposition material is also deposited on the metal mask. If the deposition material deposits near the through holes in the metal mask, the deposition of the internal electrodes may be hindered, which may result in a deterioration in the shape of the internal electrodes, such as a decrease in line width.

[0006] If the shape of the internal electrodes deteriorates, the effective area of ​​the electrodes decreases, resulting in a problem of a decrease in electrical capacity. Furthermore, if the number of times that the film deposits on the metal mask are washed is increased in order to solve the above problem, the time until the metal mask can be discarded will be shortened.

[0007] The shape of the internal electrode is strongly influenced by the cross-sectional shape of the periphery of the through-hole in the metal mask. Examples of indices that characterize the cross-sectional shape of a metal mask include the step height and taper angle.

[0008] The present inventors have conducted extensive research into the cross-sectional shape of metal masks from the above-mentioned perspectives, and have completed the present invention.

[0009] In view of the above circumstances, the present invention provides a metal mask capable of forming internal electrodes having a good shape and good electrical properties, a method for forming an internal electrode pattern of a multilayer ceramic capacitor, a method for forming internal electrodes of a multilayer ceramic capacitor, and a method for manufacturing a multilayer ceramic capacitor.

[0010] Another object of the present invention is to provide a method for managing metal masks for forming internal electrodes of multilayer ceramic capacitors, which can extend the period before the metal masks are discarded. [Means for solving the problem]

[0011] A first aspect of the present invention is a metal mask for manufacturing an internal electrode of a multilayer ceramic capacitor, the metal mask comprising a metal substrate having a through hole formed therein that is rectangular in plan view, the through hole having a dimension of 300 μm or less in a short side direction of the rectangle in plan view, the through portion of the through hole having a dimension of 300 μm or less in a short side direction of the rectangle in plan view, the cross section of a peripheral edge facing the through portion has a step height formed on one side in a thickness direction of the substrate and a tapered portion extending in a direction away from the through portion on the other side in the thickness direction, the dimension of the step height located in the short side direction in the thickness direction being 12.2 μm or less, The tapered portion located in the short side direction is a metal mask having a taper angle of 47.0° or less with respect to the short side direction.

[0012] A second aspect of the present invention is a method for forming an internal electrode pattern of a multilayer ceramic capacitor, which comprises forming the internal electrodes by physical vapor deposition using the metal mask of the first aspect.

[0013] A third aspect of the present invention is a method for forming an internal electrode of a multilayer ceramic capacitor, comprising forming the internal electrode by using the method for forming an internal electrode pattern of a multilayer ceramic capacitor according to the second aspect.

[0014] A fourth aspect of the present invention is a method for manufacturing a multilayer ceramic capacitor, comprising forming an internal electrode by using the method for forming an internal electrode of a multilayer ceramic capacitor according to the third aspect.

[0015] A fifth aspect of the present invention is a method for managing a metal mask for forming internal electrodes of a multilayer ceramic capacitor, comprising: managing an upper limit of the dimension in the thickness direction of a film deposited on the metal mask of the first aspect to be 15 μm; and cleaning the metal mask when the dimension in the thickness direction of the film reaches the upper limit. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a metal mask capable of forming internal electrodes having a good shape and good electrical properties, a method for forming an internal electrode pattern of a multilayer ceramic capacitor, a method for forming internal electrodes of a multilayer ceramic capacitor, and a method for manufacturing a multilayer ceramic capacitor.

[0017] According to the present invention, it is possible to provide a method for managing metal masks for forming internal electrodes of multilayer ceramic capacitors, which can extend the period until the metal masks are discarded. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a schematic diagram showing the positional relationship of a metal mask and the like during film formation. [Figure 2] 10A and 10B are diagrams showing the relationship between the cross-sectional shape of a through hole in a metal mask and a film formed thereon. [Figure 3] 1 is an example of a thickness profile of a nickel film. [Figure 4] FIG. 2 is a schematic plan view showing an example of a member formed using the metal mask according to the embodiment. [Figure 5] FIG. 10 is a schematic plan view showing another example of a member formed using the metal mask according to the embodiment. [Figure 6] 6 is a schematic plan view showing the positional relationship when the member in FIG. 4 is divided into two equal parts or when the members are alternately stacked after cutting either the left or right end shown in FIG. 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the metal mask, the method for forming an internal electrode pattern of a multilayer ceramic capacitor, the method for forming an internal electrode of a multilayer ceramic capacitor, the method for manufacturing a multilayer ceramic capacitor, and the method for managing a metal mask for forming an internal electrode of a multilayer ceramic capacitor will be described with reference to FIGS. 1 to 5.

[0020] The following embodiment shows one aspect of the present invention, does not limit the present invention, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure are different from the actual structure to make each configuration easier to understand.

[0021] As shown schematically in FIG. 1, the metal mask 1 according to this embodiment is placed on top of a dielectric sheet (often called a green sheet) 100 as a substrate. In physical vapor deposition processes such as sputtering and deposition, only the material that flies from the target T toward the metal mask 1 and passes through the through holes 1a is deposited on the dielectric sheet 100 and formed as a thin conductive film 101 (see FIG. 2). The material that constitutes the conductive film can be selected from metals. Examples of metals that can be used include nickel and nickel alloys containing nickel as a main component and aluminum, silver, copper, platinum, etc.

[0022] 2 is an enlarged cross-sectional view of one through hole 1a in the metal mask 1. The through hole 1a is formed by etching a sheet-like metal substrate (hereinafter simply referred to as "substrate 110") that constitutes the metal mask from both sides in the thickness direction.

[0023] When the through-hole 1a is formed by wet etching, the etching is often performed in two stages. Specifically, first, the surface 110a of the substrate 110 that is in close contact with the dielectric sheet is etched, and then the surface 110b of the substrate 110 that is on the target T side is etched, thereby forming the through-hole 1a. The surface 110a corresponds to one side of the substrate 110 in the thickness direction. The surface 110b corresponds to the other side of the substrate 110 in the thickness direction.

[0024] Because etching is isotropic, the planar dimensions of through hole 1a become larger the closer to surfaces 110a, 110b of substrate 110 and become smaller the farther from surfaces 110a, 110b of substrate 110. Therefore, when two-stage etching is performed starting from surfaces 110a, 110b of substrate 110 to fabricate metal mask 1, the planar dimensions of the formed through hole become smallest at penetrating portion 1b in the middle of substrate 110 in the thickness direction, and the planar shape and dimensions at this portion determine the planar shape of the film-formed structure.

[0025] The penetrating portion 1b, which has the smallest planar dimension, is formed at the location where etching from surfaces 110a and 110b meets, and therefore the position of the penetrating portion 1b in the thickness direction of the substrate 110 (hereinafter simply referred to as the "thickness direction") changes depending on the extent of etching from each surface.

[0026] Because the film-forming material flies radially from the target T, if it enters the through-hole 1a at an angle, it may pass through the through-hole 1b and then fly outside the area of ​​the through-hole in a plan view, reaching the dielectric sheet 100, as shown by the dashed arrow Ta in FIG. 2. This phenomenon, sometimes called the "shadow effect," occurs more frequently the farther the through-hole 1b is from the dielectric sheet 100, i.e., the larger the step height h1 (described in detail below), which is the dimension in the thickness direction from the surface 110a of the substrate 110 to the through-hole 1b. Furthermore, the stronger the shadow effect, the smaller the area of ​​the top surface of the formed thin film 101 becomes relative to the area of ​​the bottom surface. In other words, the edge of the formed thin film 101 becomes thinner than the center.

[0027] On the other hand, as indicated by the dashed arrow Tb in Figure 2, there is a possibility that the particles may fly from outside the range of the penetration portion 1b in plan view and reach the dielectric sheet 100. This phenomenon occurs due to a tapered portion h2 formed in the substrate 110 closer to the surface 110b than the penetration portion 1b. The tapered portion h2 extends in a direction away from the penetration portion 1b and in a direction in which the gap becomes larger as it moves from the penetration portion 1b toward the surface 110b. The probability of the particles flying from outside the range of the penetration portion 1b in plan view and reaching the dielectric sheet 100 increases as the position where the tapered portion h2 opens on the surface 110b is further away from the penetration portion 1b and the taper angle θ becomes smaller, and the thicker the thin film 101 formed becomes.

[0028] The taper angle θ of the tapered portion h2 is the smaller of the intersection angles at which the line segment connecting the position where the tapered portion h2 opens onto the surface 110b and the through-hole portion 1b intersects with the surface 110b in the cross-sectional shape of the peripheral edge facing the through-hole 1a.

[0029] In other words, the cross-sectional shape of the peripheral edge of the metal mask 1 facing the through hole 1a has a step height h1 formed on the surface 110a side in the thickness direction and a tapered portion h2 formed on the surface 110b side in the thickness direction, which influences the shape and thickness of the thin film 101.

[0030] Based on this, the inventors studied the step height (denoted by symbol h1 in FIG. 2) in the short side direction, which is the distance from the surface 110a that adheres to the dielectric sheet 100, which is the substrate, to the penetration portion 1b in the thickness direction of the metal mask 1, and the tapered portion h2 located in the short side direction, and studied the conditions for a metal mask suitable for manufacturing internal electrodes for MLCCs. The inventors also studied the influence of the film formed by the film material flying from the target T and depositing on the surface 110b and tapered portion h2 of the base material 110, and studied the conditions for a metal mask suitable for manufacturing internal electrodes for MLCCs. [Example]

[0031] (Metal mask sample production) As a substrate, a 50 μm thick stainless steel SUS430 sheet (plan view dimensions: 350 mm×715 mm) was prepared. The substrate was etched on both sides in a two-stage etching process to form a large number of rectangular through-holes at a fixed pitch in a plan view. The dimension of the through-holes 1b in the short side direction was 300 μm. At this time, by changing the amount of etching from both sides, metal mask samples 1-8 having the step heights and taper angles shown in Table 1 were produced.

[0032] After each sample was completed, the step height was measured by cutting the metal mask longitudinally across the through-holes, and the thickness dimension of the step height located in the short side direction was measured by laser confocal scanning using a measuring device (Keyence VK-X200) while making it possible to observe the dimension from the side of the through-hole. The taper angle was also measured by cutting the metal mask longitudinally across the through-holes, and measured from the surface 110b side, which is the target flight side, by laser confocal scanning using the same measuring device (Keyence VK-X200). Cross-sectional profile data was obtained and then processed to calculate the taper angle θ.

[0033] (Measurement of line width of thin film after deposition) Assuming repeated use of metal masks, six deposition samples were prepared for each of the metal mask samples 1-8, including samples with intentionally deposited films of 0.5 μm, 1.0 μm, 5.0 μm, 10.0 μm, and 15.0 μm thicknesses, as well as samples with no deposition (deposition amount: 0.0 μm). The deposition thickness of the deposition material on the metal mask samples was controlled by using the metal mask samples under conditions equivalent to the thin film deposition process and repeating the process of depositing 0.5 μm.

[0034] A thin film with a thickness of 150 nm was formed using each prepared metal mask sample, and the line width in the short side direction of the thin film after film formation was measured. Nickel materials were used for the thin film and the film formation target (target). The line width was measured by taking an image of the thin film by white light interference scanning using a measuring device (Keyence VK-X3000). The obtained thin film image was then used to obtain a cross-sectional profile at the center of the short side using the VK-X3000 multi-file analysis application software.

[0035] FIG. 3 is an example of a thickness profile of a nickel film. As shown in FIG. 3, a straight line parallel to the bottom surface was set at the position of the maximum height H-10 nm of the film formation, and the distance W between the intersection of this straight line and the film formation profile was defined as the line width. The measured line width was expressed as a ratio based on the line width of a thin film formed using a metal mask sample with a deposition amount of 0.0 μm.

[0036] (Evaluation method) Samples showing a change within the typical "20% guaranteed capacitance value for MLCCs" were marked "○" (OK), and samples showing a change exceeding 20% ​​were marked "×" (NG).

[0037] [Table 1]

[0038] As shown in Table 1, for metal mask samples 1-6, in which the step height dimension in the thickness direction is 12.2 μm or less and the taper angle of the tapered portion located in the short side direction with respect to the short side direction is 47.0° or less, it was confirmed that good film formation could be achieved with a variation of less than 20% for all samples in which the deposition thickness of the film was 0.0 μm to 15.0 μm.

[0039] Therefore, by using a metal mask in which the step height dimension in the thickness direction is 12.2 μm or less and the taper angle of the tapered portion located in the short side direction relative to the short side direction is 47.0° or less, good film formation can be achieved with a variation of less than 20% even if the deposition thickness of the film is 15.0 μm.Therefore, the deposition thickness of the film can be used as an indicator when cleaning the metal mask, and a management method for metal masks for forming internal electrodes of MLCCs can be set according to this indicator.

[0040] Specifically, the method for managing metal masks for forming internal electrodes of MLCCs includes managing the upper limit of the thickness dimension of the film deposited on the metal mask to 15 μm, and cleaning the metal mask when the thickness dimension of the film reaches the upper limit.

[0041] On the other hand, in the case of the metal mask sample of Sample 7-8, when the deposition thickness of the film was 15.0 μm, the taper angle exceeded 47.0° even though the dimension of the step height in the thickness direction was 12.2 μm or less, so the change exceeded 20% and a good evaluation was not obtained. That is, Samples 1-6 in this embodiment are examples, and Samples 7-8 are comparative examples.

[0042] This is thought to be because the large taper angle reduces the possibility of the film material flying from outside the range of the penetration portion 1b in a planar view and reaching the dielectric sheet 100, and also because a large amount of the film material is deposited from the penetration portion 1b to the tapered portion, which blocks the film material flying from the target T, thereby inhibiting the formation of a thin film.

[0043] Furthermore, by setting the thickness dimension of the step height to 12.2 μm or less and the taper angle of the tapered portion located in the short side direction relative to the short side direction to 47.0° or less, it was possible to achieve (line width in the short side direction of the thin film formed on a metal mask sample with a deposition thickness of the film formed of 1.0 μm) / (line width in the short side direction of the thin film formed on a metal mask sample with a deposition thickness of the film formed of 0.0 μm) ≧ 0.97.

[0044] Furthermore, by setting the thickness dimension of the step height to 12.2 μm or less and the taper angle of the tapered portion located in the short side direction relative to the short side direction to 47.0° or less, it was possible to achieve (line width in the short side direction of the thin film formed on a metal mask sample with a deposition thickness of the film formed of 5.0 μm) / (line width in the short side direction of the thin film formed on a metal mask sample with a deposition thickness of the film formed of 0.0 μm) ≧ 0.92.

[0045] Furthermore, by setting the thickness dimension of the step height to 12.2 μm or less and the taper angle of the tapered portion located in the short side direction relative to the short side direction to 47.0° or less, it was possible to achieve (line width in the short side direction of the thin film formed on a metal mask sample with a deposition thickness of the film formed of 10.0 μm) / (line width in the short side direction of the thin film formed on a metal mask sample with a deposition thickness of the film formed of 0.0 μm) ≧ 0.90.

[0046] Furthermore, by setting the thickness dimension of the step height to 12.2 μm or less and the taper angle of the tapered portion located in the short side direction relative to the short side direction to 47.0° or less, it was possible to achieve (line width in the short side direction of the thin film formed on a metal mask sample with a deposition thickness of the film formed of 15.0 μm) / (line width in the short side direction of the thin film formed on a metal mask sample with a deposition thickness of the film formed of 0.0 μm) ≧ 0.80.

[0047] On the other hand, it was confirmed that in the metal mask samples of Sample 1-4, which have a taper angle of 44.6° or less and a step height dimension in the thickness direction of 1.8 μm or more, better film formation can be achieved than in the metal mask samples of Sample 5-6, in samples with deposition thicknesses of 5.0 μm and 15.0 μm.

[0048] Furthermore, it was confirmed that the metal mask samples of sample 1-2, which have a taper angle of 40.3° or less and a step height dimension in the thickness direction of 10.0 μm or more, can achieve even better film formation than the metal mask samples of sample 3-6, in samples with deposition thicknesses of 5.0 μm, 10.0 μm, and 15.0 μm.

[0049] (Measurement of thin film thickness after deposition) Apart from the line width of the thin film after the film formation, the film thickness of the thin film after the film formation was also measured. Using the above-mentioned metal mask samples, assuming repeated use of the metal masks, six film-formed samples were prepared for each of the metal mask samples, Samples 1-5 and Samples 7-8, including samples on which film formation was intentionally deposited to thicknesses of 0.5 μm, 1.0 μm, 5.0 μm, 10.0 μm, and 15.0 μm, and samples on which no film formation was deposited (deposition amount: 0.0 μm).

[0050] A 150 nm-thick thin film was formed using each prepared metal mask sample, and the film thickness of the formed thin film was measured. Nickel material was used for the thin film and the film-forming object (target). The film thickness of the formed thin film was defined as the maximum height H of the film, as shown in Figure 3. The measured film thickness was expressed as a ratio based on the film thickness of a thin film formed using a metal mask sample with a deposition amount of 0.0 μm.

[0051] (Evaluation method) For samples with a deposition amount of 15.0 μm, samples showing a change in film thickness of less than 10% were marked as "○" (OK), and samples showing a change in film thickness of more than 10% were marked as "×" (NG).

[0052] [Table 2]

[0053] As shown in Table 2, for metal mask samples 3-5, in which the step height dimension in the thickness direction is 8.3 μm or less and the taper angle of the tapered portion located in the short side direction with respect to the short side direction is 42.1° or more and 47.0° or less, it was confirmed that good film formation could be achieved with a variation of less than 10% for all samples with deposition thicknesses of the film ranging from 0.0 μm to 15.0 μm.

[0054] On the other hand, in the metal mask sample of Sample 1-2, the change in film thickness exceeded 10% in at least one of the deposition thicknesses of 1.0 μm, 5.0 μm, 10.0 μm, and 15.0 μm, and the sample was not evaluated as good. This is probably because the large thickness dimension of the step height created a strong shadow effect, causing much of the deposition material to reach the edges, which do not contribute to the maximum film thickness. Also, it is thought that the deposition material was deposited in large amounts from the penetration portion 1b to the tapered portion, blocking the deposition material flying from the target T, inhibiting the formation of the thin film.

[0055] Thus, if the change in film thickness exceeds 10%, 1.1 times or more film-forming steps are required to form the same film thickness, and the time required to repeatedly laminate thin films on one dielectric sheet 100 is proportionally 1.1 times or more, which is undesirable as it reduces production efficiency and also reduces the stability of the total film thickness. Therefore, the above-mentioned inconvenience can be resolved by setting the dimension of the step height in the thickness direction to 8.3 μm or less and setting the taper angle of the tapered portion located in the short side direction to 42.1° or more and 47.0° or less with respect to the short side direction.

[0056] On the other hand, in the metal mask sample of Sample 3-4, in which the step height dimension in the thickness direction is 3.1 μm or less and the taper angle of the tapered portion located in the short side direction with respect to the short side direction is 42.1° or more and 47.0° or less, it was confirmed that better film formation could be achieved than in the metal mask sample of Sample 5 in samples with deposition thicknesses of the film formed of 1.0 μm, 5.0 μm, and 10.0 μm.

[0057] Furthermore, it was confirmed that the metal mask sample of sample 4, in which the step height dimension in the thickness direction is 1.9 μm or less and the taper angle of the tapered portion located in the short side direction with respect to the short side direction is 44.6° or more, can perform better film formation than the metal mask sample of sample 5 in samples with deposition thicknesses of the film formed of 5.0 μm, 10.0 μm, and 15.0 μm.

[0058] 4 shows an example of a component 50 serving as an internal electrode for an MLCC, formed using the metal mask according to this embodiment. The component 50 has a structure in which a thin film 20 made of a conductor is formed as an internal electrode on a substrate (dielectric sheet) 10 made of a dielectric by a method for forming an internal electrode that includes a method for forming an internal electrode pattern by sputtering, which is a type of physical vapor deposition method, using the metal mask according to this embodiment.

[0059] Since the thin film 20 is formed using the metal mask according to this embodiment, the line width in the short side direction is 80% or more of the line width when no film is deposited on the metal mask. The member 50 shown in Fig. 4 is divided into two equal parts, member 50A and member 50B, in the longitudinal direction as shown by the dashed line, to form an internal electrode for an MLCC, and multiple members are stacked so that the margins 11 without the thin film 20 are staggered as shown in Fig. 6. The member 50 shown in Fig. 5 is cut at either the left or right end in the longitudinal direction as shown by the dashed line to form an internal electrode for an MLCC, and multiple members are stacked so that the margins 11 without the thin film 20 in Fig. 6 are staggered.

[0060] That is, the manufacturing method of an MLCC (manufacturing method of a multilayer ceramic capacitor) includes forming a thin film 20 that will become an internal electrode on a substrate 10 shown in FIG. 4 by an internal electrode forming method including the above-mentioned method of forming an internal electrode pattern, dividing the substrate 10 shown in FIG. 4 on which the internal electrode has been formed into two equal parts in the longitudinal direction into members 50A and 50B, and stacking a plurality of the two equal parts of the substrate 10 so that the margins 11 without the thin film 20 shown in FIG. 6 are staggered.

[0061] The method also includes cutting either the left or right end in the longitudinal direction of each of two thin film 20 regions of the member 50 shown in Figure 5 by a method for forming an internal electrode including the method for forming an internal electrode pattern described above, and stacking a plurality of the cut substrates 10 so that the margins 11 without thin film 20 shown in Figure 6 are alternately arranged.

[0062] The member 50 shown in Fig. 4 can contribute to the favorable production of an MLCC that guarantees the above-mentioned capacitance because the line width of the thin film is maintained within a predetermined range even after it is divided into two equal parts, member 50A and member 50B. The member 50 shown in Fig. 5 can contribute to the favorable production of an MLCC that guarantees the above-mentioned capacitance because the line width of the thin film is maintained within a predetermined range even after it is cut into two thin film 20 regions, member 50A and member 50B.

[0063] Fig. 6 is a diagram showing the positional relationship when the member 50 shown in Fig. 4 is divided into two equal parts, or when the two thin film 20 regions shown in Fig. 5 are alternately stacked after either the left or right end in the longitudinal direction is cut. In practice, this combination is counted as one set, and many sets are stacked.

[0064] As shown in Fig. 6, members 50A and 50B, which are obtained by dividing the member 50 shown in Fig. 4, are stacked with both ends in the longitudinal direction symmetrical. In the case of the member 50 shown in Fig. 5, members 50A and 50B, which are obtained by cutting either the left or right end of each of the two thin film 20 regions, are stacked with both ends in the longitudinal direction symmetrical.

[0065] 6, where the thin film 20A of the member 50A and the thin film 20B of the member 50B overlap, essentially functions as a capacitor. Then, in a stacked state, the thin film 20A of the member 50A exposed at the end (right end) in the longitudinal direction and the thin film 20B of the member 50B exposed at the end (left end) in the longitudinal direction are connected to external terminals, respectively.

[0066] As described above, in the metal mask 1 of this embodiment, the dimension of the penetrating portion 1b in the short side direction is 300 μm or less, the dimension in the thickness direction of the step height h1 located in the short side direction is 12.2 μm or less, and the taper angle of the tapered portion h2 located in the short side direction with respect to the short side direction is 47.0° or less, so that the shape of the internal electrode is good and it is possible to form an internal electrode with good electrical properties.

[0067] Furthermore, since the metal mask 1 of this embodiment experiences little reduction in effective area when used repeatedly, in the method for managing a metal mask for forming internal electrodes of an MLCC, the number of times the metal mask 1 is washed can be reduced by setting the upper limit of the thickness direction dimension of the film deposited on the metal mask 1 to 15 μm, thereby making it possible to extend the period until the metal mask 1 is discarded.

[0068] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0069] For example, the substrate of the metal mask according to the present invention is not limited to stainless steel such as SUS430 used in the above study. For example, other magnetic metal substrates made of alloys such as Invar or Super Invar may also be used. When the thin film metal substrate is made of a magnetic metal material such as those described above, there is an advantage in that it can be fixed to the film deposition apparatus using magnetic force. Furthermore, the thickness of the substrate is not limited to 50 μm as in the above study, and even if the thickness is different, the same effect can be achieved by setting the step height or taper angle within the above range.

[0070] In addition, when the metal mask according to the present invention is mounted in a normal film forming apparatus, either surface in the thickness direction can be made to face the substrate, and the step height changes accordingly. However, the step height in the present invention is defined as the lower of the above values. Furthermore, in view of the manufacturing process, the step height in the metal mask according to the present invention is different from the cross section in the short side direction of the through hole in the long side direction. Therefore, in order to clarify the definition, the step height in the cross section extending in the long side direction of the portion forming the edge of the short side of the through hole will be used, i.e., the step height in the short side direction. [Explanation of symbols]

[0071] 1 Metal Mask 1a Through hole 1b Penetration part 10 Substrate 20 Thin film (internal electrode) 21 Top side 22 bottom 100 Dielectric sheet (substrate) 110 Base material h1 Step height h2 Tapered section

Claims

1. A metal mask for manufacturing an internal electrode of a multilayer ceramic capacitor, the metal mask comprising a metal substrate having a through hole that is rectangular in plan view formed therein, The dimension of the through hole in the short side direction of the rectangle in plan view is 300 μm or less. In the cross-sectional shape of the peripheral edge facing the through-hole portion, a step height is formed on one side in the thickness direction of the base material, and a tapered portion extending in a direction away from the through-hole portion is formed on the other side in the thickness direction, The dimension in the thickness direction of the step height located in the short side direction is 12.2 μm or less, The metal mask, wherein the tapered portion located in the short side direction has a taper angle with respect to the short side direction of 47.0° or less.

2. The taper angle is 44.6° or less, The dimension of the step height in the thickness direction is 1.8 μm or more. The metal mask according to claim 1 .

3. The taper angle is 40.3° or less, The dimension of the step height in the thickness direction is 10.0 μm or more. The metal mask according to claim 2 .

4. The dimension of the step height in the thickness direction is 8.3 μm or less, The taper angle is 42.1° or more and 47.0° or less. The metal mask according to claim 1 .

5. The dimension of the step height in the thickness direction is 3.1 μm or less. The metal mask according to claim 4.

6. The dimension of the step height in the thickness direction is 1.9 μm or less, The taper angle is 44.6° or more. The metal mask according to claim 5 .

7. forming the internal electrodes by physical vapor deposition using the metal mask according to any one of claims 1 to 6; A method for forming an internal electrode pattern of a multilayer ceramic capacitor.

8. A method for forming an internal electrode of a multilayer ceramic capacitor, comprising forming the internal electrode by using the method for forming an internal electrode pattern of a multilayer ceramic capacitor according to claim 7.

9. A method for manufacturing a multilayer ceramic capacitor, comprising forming the internal electrodes by using the method for forming internal electrodes of a multilayer ceramic capacitor according to claim 8.

10. 7. The upper limit of the dimension in the thickness direction of the film deposited on the metal mask according to claim 1 is controlled to 15 μm; cleaning the metal mask when the dimension in the thickness direction of the film-formed object reaches the upper limit; A method for managing a metal mask for forming an internal electrode of a multilayer ceramic capacitor, comprising:

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