A metal mask, a method for forming an internal electrode pattern in a multilayer ceramic capacitor, a method for forming an internal electrode in a multilayer ceramic capacitor, a method for manufacturing a multilayer ceramic capacitor, and a method for managing a metal mask for forming an internal electrode in a 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 an internal electrode of a multilayer ceramic capacitor, a method for manufacturing a multilayer ceramic capacitor, and a method for managing a metal mask for forming an internal electrode of a multilayer ceramic capacitor.

Background Art

[0002] MLCC is a chip component type capacitor in which internal electrodes and dielectric sheets (often referred to as green sheets) are laminated in multiple layers. While MLCCs are becoming smaller, they are also required to have sufficient capacitance as capacitors. In order to increase the capacitance without increasing the size, it is necessary to reduce the film thickness of the internal electrodes and increase the number of lamination layers. Conventionally, screen printing has been used for forming internal electrodes, but by using a sputtering method, it is expected that the internal electrodes can be formed with a thinner film and the number of lamination layers can be increased compared to the conventional method.

[0003] As one method for manufacturing a metal mask used in sputtering, vapor deposition, etc., there is a method of manufacturing by wet etching a thin film metal substrate (see, for example, Patent Document 1). The material flying from the target is formed into a film with a predetermined dimension and shape at a predetermined position by passing through the through holes formed by etching.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the sputtering method described above, the deposited material is also deposited on the metal mask. If the deposited material accumulates near through holes in the metal mask, the deposition of the internal electrodes may be inhibited, potentially leading to a narrowing of the line width and other deterioration of the shape of the internal electrodes.

[0006] If the shape of the internal electrodes deteriorates, a problem arises in which the effective area of ​​the electrodes decreases and the electrical capacitance drops. Furthermore, if the number of times the deposited film on the metal mask is washed is increased to resolve the above problem, a problem arises in which the period before the metal mask needs to be discarded is shortened.

[0007] The shape of the internal electrodes strongly reflects the cross-sectional shape of the periphery of the through-holes in the metal mask. Indicators that characterize the cross-sectional shape of a metal mask include step height and taper angle.

[0008] The inventors of the present invention have conducted various studies on the cross-sectional shape of the metal mask from the above perspective and have completed the present invention.

[0009] Based on the above circumstances, the present invention provides a metal mask capable of forming internal electrodes with a good shape and good electrical characteristics, a method for forming an internal electrode pattern for a multilayer ceramic capacitor, a method for forming internal electrodes for 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 used for forming internal electrodes in multilayer ceramic capacitors, which can extend the period before the metal masks need to be discarded. [Means for solving the problem]

[0011] A first aspect of the present invention is a metal mask for manufacturing internal electrodes of a multilayer ceramic capacitor, wherein a rectangular through-hole is formed in a metal substrate, the dimensions of the through-hole in the direction of the shorter side of the rectangle in the direction of the rectangle in the direction of the rectangle are 300 μm or less, the cross-sectional shape of the periphery facing the through-hole is such that a step height is formed on one side in the thickness direction of the substrate, and a tapered portion extending away from the through-hole is formed on the other side in the thickness direction, the dimensions of the step height located in the direction of the shorter side in the thickness direction are 12.2 μm or less, and the tapered portion located in the direction of the shorter side has a taper angle of 47.0° or less with respect to the direction of the shorter side. It is a sputtering mask used to perform sputtering in a desired pattern. Metal Mask

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

[0013] A third aspect of the present invention is a method for forming internal electrodes of a multilayer ceramic capacitor, comprising forming the internal electrodes using the method for forming the 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 the internal electrodes using the method for forming the internal electrodes 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: controlling the upper limit of the thickness dimension of a film deposited on the metal mask of the first aspect to 15 μm; and cleaning the metal mask when the thickness dimension 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 in which the shape of the internal electrode is good and an internal electrode having good electrical characteristics can be formed, a method for forming an internal electrode pattern of a multilayer ceramic capacitor, a method for forming an internal electrode 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 a metal mask for forming an internal electrode of a multilayer ceramic capacitor, which can extend the period until the metal mask is discarded.

Brief Description of the Drawings

[0018] [Figure 1] It is a schematic diagram showing the positional relationship of a metal mask or the like during film formation. [Figure 2] It is a diagram showing the relationship between the cross-sectional shape of the metal mask through-hole and the film-formed product. [Figure 3] It is an example of the thickness profile of the nickel film. [Figure 4] It is a schematic plan view showing an example of a member formed using the metal mask according to the present embodiment. [Figure 5] It is a schematic plan view showing another example of a member formed using the metal mask according to the present embodiment. [Figure 6] It is a schematic plan view showing the positional relationship when the member of FIG. 4 is bisected or when the left or right end shown in FIG. 5 is cut and then laminated alternately.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the metal mask of the present invention, a method for forming an internal electrode pattern of a multilayer ceramic capacitor, a method for forming an internal electrode of a multilayer ceramic capacitor, a method for manufacturing a multilayer ceramic capacitor, and a 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] Note that the following embodiments show one aspect of the present invention, do not limit this invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Also, in the following drawings, in order to make each configuration easier to understand, the actual structure, the scale, the number, etc. in each structure are made different.

[0021] As schematically shown in FIG. 1, the metal mask 1 according to the present embodiment is installed so as to be overlaid on a dielectric sheet (often called a green sheet) 100 as a substrate. In processes such as physical vapor deposition sputtering and vapor deposition, among the materials flying from the target T toward the metal mask 1, only those passing through the through-hole 1a are deposited on the dielectric sheet 100 and formed into a thin film 101 (see FIG. 2) of a conductive film. As the material constituting the conductive film, a metal can be selected. As the metal, for example, nickel or a nickel alloy mainly composed of nickel containing aluminum, silver, copper, platinum, etc. can be used.

[0022] FIG. 2 is a cross-sectional view showing an enlarged view of one through-hole 1a in the metal mask 1. The through-hole 1a is formed by etching a sheet-like metal base material (hereinafter simply referred to as "base material 110") constituting 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 steps. Specifically, first, the surface 110a on the side of the base material 110 that adheres to the dielectric sheet is etched, and then the surface 110b on the target T side of the base material 110 is etched to form the through-hole 1a. The surface 110a corresponds to one side in the thickness direction of the base material 110. The surface 110b corresponds to the other side in the thickness direction of the base material 110.

[0024] Because etching is isotropic, the planar dimensions of the through-holes 1a are larger closer to the surfaces 110a and 110b of the substrate 110, and smaller as they move away from the surfaces 110a and 110b of the substrate 110. Therefore, when two-stage etching is performed from the surfaces 110a and 110b of the substrate 110 when fabricating the metal mask 1, the planar dimensions of the formed through-holes are smallest at the through-hole portion 1b in the middle of the thickness direction of the substrate 110, and the planar shape and dimensions at this portion define the planar shape of the film-deposited structure.

[0025] The penetration portion 1b, which has the smallest dimensions in plan view, is formed at the point where etching from surfaces 110a and 110b collide. Therefore, the position of the penetration 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] Since the film deposition material flies radially from the target T, if it enters the through-hole 1a at an angle, as shown by the dashed arrow Ta in Figure 2, it may fly beyond the range of the through-hole 1b in a plan view and reach the dielectric sheet 100. This phenomenon is sometimes called the "shadow effect," and its probability of occurrence increases as the through-hole 1b moves further away from the dielectric sheet 100, that is, as the step height h1 (details described later), which is the thickness dimension from the surface 110a of the substrate 110 to the through-hole 1b, increases. Furthermore, the stronger the shadow effect, the smaller the area of ​​the upper surface s of the formed thin film 101 becomes compared to the area of ​​the bottom surface. In other words, the edges of the formed thin film 101 become thinner compared to the center.

[0027] On the other hand, as shown by the dashed arrow Tb in Figure 2, it is possible for particles to fly from outside the range of the penetration portion 1b in a plan view and reach the dielectric sheet 100. This phenomenon is caused by a tapered portion h2 formed on the substrate 110 on the surface 110b side of the penetration portion 1b. The tapered portion h2 extends in a direction that moves away from the penetration portion 1b and increases the void as it moves toward the surface 110b side from the penetration portion 1b. The probability of the phenomenon occurring, where particles fly from outside the range of the penetration portion 1b in a plan view and reach the dielectric sheet 100, increases as the position where the tapered portion h2 opens to the surface 110b moves away from the penetration portion 1b and the taper angle θ is small, and the formed thin film 101 becomes thicker.

[0028] The taper angle θ of the tapered portion h2 is the smaller of the angles of intersection between the line segment connecting the position where the tapered portion h2 opens to the surface 110b and the through portion 1b, in the cross-sectional shape of the periphery facing the through hole 1a.

[0029] In other words, the metal mask 1 has a configuration that influences the shape and thickness of the thin film 101 in the cross-sectional shape of the periphery facing the through hole 1a, with 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.

[0030] Based on this, the inventors investigated the step height (indicated by the symbol h1 in Figure 2), which is the distance from the surface 110a in close contact with the dielectric sheet 100 substrate in the thickness direction of the metal mask 1 to the through-hole 1b, and the tapered portion h2 located in the short-side direction, and investigated the conditions for a metal mask suitable for manufacturing internal electrodes for MLCCs. Furthermore, the inventors investigated the influence of the film formed by the deposition of film-forming material flying from the target T onto the surface 110b and tapered portion h2 on the substrate 110, and investigated the conditions for a metal mask suitable for manufacturing internal electrodes for MLCCs. [Examples]

[0031] (Preparation of metal mask samples) A sheet of SUS430 stainless steel with a thickness of 50 μm (planar dimensions 350 mm x 715 mm) was prepared as the base material. The substrate was etched on both sides using a two-stage etching process to create numerous through-holes that were rectangular in shape when viewed from above, at a constant pitch. The dimensions of the through-hole portion 1b in the short-side direction were set to 300 μm. In this process, metal mask samples 1-8 with the step height and taper angle shown in Table 1 were prepared by changing the amount of etching from both sides.

[0032] After each sample was completed, the step height was measured by cutting the metal mask longitudinally across the through-hole, allowing observation of the thickness dimension of the step height located in the short-side direction from the side facing the through-hole, and then measuring it using a laser confocal scan with a measuring instrument (Keyence VK-X200). The taper angle was also measured by cutting the metal mask longitudinally across the through-hole and measuring it from the surface 110b side, which is the flight side of the target, using the same measuring instrument (Keyence VK-X200) and obtaining cross-sectional profile data, which was then processed to calculate the taper angle θ.

[0033] (Measuring the line width of the thin film after deposition) With the intention of repeatedly using the metal masks, six deposition samples were prepared for each metal mask sample from Sample 1 to 8, including samples with intentionally deposited films of thicknesses of 0.5 μm, 1.0 μm, 5.0 μm, 10.0 μm, and 15.0 μm, respectively, and samples without any deposition (deposit amount: 0.0 μm). The deposition thickness of the film on the metal mask samples was controlled by using the metal mask samples under conditions equivalent to those of the thin film deposition process, and repeatedly depositing a 0.5 μm film.

[0034] Thin films with a thickness of 150 nm were deposited using each prepared metal mask sample, and the linewidth in the short-side direction of the deposited thin film was measured. Nickel material was used for both the thin film and the deposited material (target). Line width was measured by acquiring images of the thin film using white light interference scanning with a measuring instrument (Keyence VK-X3000). The acquired images of the thin film were then used with the VK-X3000 multi-file analysis application software to obtain a cross-sectional profile at the center of the short side.

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

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

[0037] [Table 1]

[0038] As shown in Table 1, in metal mask samples 1-6, where the step height dimension in the thickness direction was 12.2 μm or less and the taper angle of the tapered portion located in the short-side direction was 47.0° or less, it was confirmed that good film deposition could be achieved with a variation of 20% or less for all samples with a deposition thickness of 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 with respect to the short-side direction is 47.0° or less, good film deposition can be achieved with a deposition thickness of 15.0 μm, but with a change of less than 20%. Thus, the deposition thickness of the deposited film can be used as an indicator when cleaning the metal mask, and a management method for the metal mask for forming internal electrodes of MLCCs can be set according to this indicator.

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

[0041] On the other hand, in the metal mask samples of Samples 7-8, when the deposition thickness of the deposited film was 15.0 μm, even though the step height dimension in the thickness direction was 12.2 μm or less, the taper angle exceeded 47.0°, resulting in a change of more than 20%, and a satisfactory evaluation could not be obtained. In other words, Samples 1-6 in this embodiment are examples, and Samples 7-8 are comparative examples.

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

[0043] Furthermore, by setting the step height in the thickness direction to 12.2 μm or less, and the taper angle of the tapered portion located in 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 deposited on a metal mask sample with a deposition thickness of 1.0 μm) / (line width in the short-side direction of the thin film deposited on a metal mask sample with a deposition thickness of 0.0 μm) ≥ 0.97.

[0044] Furthermore, by setting the step height in the thickness direction to 12.2 μm or less, and the taper angle of the tapered portion located in 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 deposited on a metal mask sample with a deposition thickness of 5.0 μm) / (line width in the short-side direction of the thin film deposited on a metal mask sample with a deposition thickness of 0.0 μm) ≥ 0.92.

[0045] Furthermore, by setting the step height in the thickness direction to 12.2 μm or less, and the taper angle of the tapered portion located in 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 deposited on a metal mask sample with a deposition thickness of 10.0 μm) / (line width in the short-side direction of the thin film deposited on a metal mask sample with a deposition thickness of 0.0 μm) ≥ 0.90.

[0046] Furthermore, by setting the step height in the thickness direction to 12.2 μm or less, and the taper angle of the tapered portion located in 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 deposited on a metal mask sample with a deposition thickness of 15.0 μm) / (line width in the short-side direction of the thin film deposited on a metal mask sample with a deposition thickness of 0.0 μm) ≥ 0.80.

[0047] On the other hand, in the metal mask samples 1-4, where the taper angle was 44.6° or less and the step height in the thickness direction was 1.8 μm or more, it was confirmed that better film deposition could be achieved in samples with deposition thicknesses of 5.0 μm and 15.0 μm compared to the metal mask samples 5-6.

[0048] Furthermore, in 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, it was confirmed that better film deposition could be achieved in samples with deposition thicknesses of 5.0 μm, 10.0 μm, and 15.0 μm compared to the metal mask samples of Sample 3-6.

[0049] (Measurement of film thickness after deposition) In addition to measuring the line width of the thin film after deposition, the film thickness of the thin film after deposition was also measured. Using the metal mask samples described above, and anticipating repeated use of the metal masks, six film-deposited samples were prepared for each of the metal mask samples 1-5 and 7-8. These samples included those with intentionally deposited films of thicknesses of 0.5 μm, 1.0 μm, 5.0 μm, 10.0 μm, and 15.0 μm, respectively, as well as those without any film deposition (deposit thickness: 0.0 μm).

[0050] Thin films with a thickness of 150 nm were deposited using each prepared metal mask sample, and the film thickness of the deposited films was measured. Nickel material was used for both the thin films and the deposited material (target). The film thickness of the deposited films was defined as the maximum deposition height H shown in Figure 3. The measured film thickness was expressed as a ratio to the film thickness of a thin film deposited using a metal mask sample with a deposition amount of 0.0 μm.

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

[0052] [Table 2]

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

[0054] On the other hand, in the metal mask samples of Sample 1-2, the change in film thickness exceeded 10% at at least one of the deposition thicknesses of 1.0 μm, 5.0 μm, 10.0 μm, and 15.0 μm, resulting in unsatisfactory evaluation. This may be because the large step height in the thickness direction resulted in a strong shadow effect, causing the deposition material to reach the edges where it did not contribute to the maximum thickness of the thin film. Furthermore, the deposition of a large amount of material from the through-hole 1b to the tapered section likely obstructed the deposition material flying from target T, thus hindering thin film formation.

[0055] Thus, when the change in film thickness exceeds 10%, it becomes necessary to perform 1.1 times or more of the film deposition process to form the same film thickness. This also proportionally increases the time required to repeatedly laminate thin films onto a single dielectric sheet 100 by 1.1 times or more, resulting in decreased production efficiency and poor overall stability of the deposited film thickness, which is undesirable. Therefore, by setting the step height in the thickness direction to 8.3 μm or less and the taper angle of the tapered portion located in the short-side direction to 42.1° or more and 47.0° or less, the above-mentioned disadvantages can be resolved.

[0056] On the other hand, in the metal mask samples of Samples 3-4, where 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 is 42.1° or more and 47.0° or less, it was confirmed that better film deposition could be achieved than in the metal mask sample of Sample 5 for samples with deposition thicknesses of 1.0 μm, 5.0 μm, and 10.0 μm.

[0057] Furthermore, in the metal mask sample of Sample 4, where 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 is 44.6° or more relative to the short-side direction, it was confirmed that better film deposition could be achieved than in the metal mask sample of Sample 5 for samples with deposition thicknesses of 5.0 μm, 10.0 μm, and 15.0 μm.

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

[0059] The thin film 20 is formed using the metal mask according to this embodiment, so that 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 Figure 4 is divided into two equal parts, member 50A and member 50B, in the longitudinal direction, as shown by the dashed line, to become an internal electrode for MLCCs, and multiple layers are stacked so that the blank spaces 11 without the thin film 20 are staggered, as shown in Figure 6. The member 50 shown in Figure 5 is cut off at either the left or right end in the longitudinal direction, as shown by the dashed line, to become an internal electrode for MLCCs, and multiple layers are stacked so that the blank spaces 11 without the thin film 20, as shown in Figure 6, are staggered, as shown in Figure 6.

[0060] In other words, the method for manufacturing an MLCC (multilayer ceramic capacitor) includes forming a thin film 20 that will become an internal electrode on a substrate 10 shown in Figure 4 by an internal electrode formation method including the method for forming the internal electrode pattern described above; dividing the substrate 10 shown in Figure 4, on which the internal electrodes have been formed, into two equal parts in the longitudinal direction, member 50A and member 50B; and stacking multiple halves of the divided substrate 10 so that the blank spaces 11 without the thin film 20 shown in Figure 6 are staggered.

[0061] Furthermore, the method for forming internal electrodes, including the method for forming the internal electrode pattern described above, involves cutting one end of either the left or right side in the longitudinal direction of each of the two thin film 20 regions of the member 50 shown in Figure 5, and stacking multiple cut substrates 10 such that the blank spaces 11 without the thin film 20, as shown in Figure 6, are staggered.

[0062] The member 50 shown in Figure 4 maintains a predetermined line width even after being divided into two equal parts, member 50A and member 50B, thus contributing to the suitability of fabricating an MLCC that guarantees the capacitance described above. The member 50 shown in Figure 5 maintains a predetermined line width even after being cut into two parts, member 50A and member 50B, in each of the two thin film 20 regions, thus contributing to the suitability of fabricating an MLCC that guarantees the capacitance described above.

[0063] Figure 6 shows the positional relationship when the member 50 shown in Figure 4 is divided into two equal parts, or when one of the two ends of each of the thin film regions 20 shown in Figure 5 is cut in the longitudinal direction and then the layers are stacked alternately. In reality, this combination forms one set, and many such sets are stacked on top of each other.

[0064] As shown in Figure 6, when the member 50 shown in Figure 4 is divided into two equal parts, member 50A and member 50B, they are stacked with their longitudinal ends symmetrical. In the case of the member 50 shown in Figure 5, when one end of either the left or right side of each of the two thin film 20 regions is cut off, member 50A and member 50B are stacked with their longitudinal ends symmetrical.

[0065] In the stacked components 50A and 50B, the area where the thin film 20A of component 50A and the thin film 20B of component 50B overlap, as shown by the dashed line in Figure 6, functions as an effective capacitor. External terminals are then connected to the stacked components, with the thin film 20A of component 50A exposed at the longitudinal end (right end) and the thin film 20B of component 50B exposed at the longitudinal end (left end).

[0066] As described above, in the metal mask 1 of this embodiment, the dimensions of the through portion 1b in the short-side direction are 300 μm or less, the thickness dimension 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 is 47.0° or less with respect to the short-side direction. Therefore, the shape of the internal electrodes is good, and it becomes possible to form internal electrodes with good electrical characteristics.

[0067] Furthermore, in the metal mask 1 of this embodiment, the reduction in effective area when used repeatedly is small. Therefore, in the management method for the metal mask for forming internal electrodes of MLCCs, the number of times the metal mask 1 is washed can be reduced by managing the upper limit of the thickness dimension of the deposited film on the metal mask 1 to 15 μm. As a result, it becomes possible to extend the period before the metal mask 1 is discarded.

[0068] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these examples. The shapes and combinations of the constituent members shown in the above examples are merely examples, and can be modified in various ways 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-mentioned study. For example, other magnetic metal substrates made of alloys such as Invar or SuperInvar may be used. If the thin-film metal substrate is formed of a magnetic metal material as described above, it has the advantage 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 described above; similar effects can be achieved with different thicknesses by using the step height or taper angle within the range described above.

[0070] In addition, when the metal mask according to the present invention is attached to a film deposition apparatus, either surface in the thickness direction can be positioned facing the substrate, and the step height will change accordingly. However, in this invention, the step height is defined as the lower of the above values. Furthermore, in light of the manufacturing process, the step height of the metal mask according to the present invention is the step height in the cross-section extending in the long-side direction of the through hole, which is the portion that forms the edge of the short side of the through hole, in order to clarify the definition, in order to clarify the definition, the step height in the short-side direction is used. [Explanation of Symbols]

[0071] 1 Metal Mask 1a Through hole 1b Penetration part 10 circuit boards 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 internal electrodes of a multilayer ceramic capacitor, wherein a rectangular through-hole is formed in a metal substrate in a plan view, The dimensions of the through-hole in the direction of the shorter side of the rectangle in plan view are 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 base material, and a tapered portion extending away from the through 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 tapered portion located in the direction of the shorter side has a taper angle of 47.0° or less with respect to the direction of the shorter side. A metal mask is a sputtering mask used to perform sputtering in a desired pattern.

2. The aforementioned 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 aforementioned 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 aforementioned taper angle is 42.1° or greater 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 aforementioned taper angle is 44.6° or greater. The metal mask according to claim 5.

7. The process includes forming the internal electrodes by physical vapor phase growth using a metal mask according to any one of claims 1 to 6. A method for forming the internal electrode pattern of a multilayer ceramic capacitor.

8. A method for forming internal electrodes of a multilayer ceramic capacitor, comprising forming the internal electrodes using the method for forming the internal electrode pattern of a multilayer ceramic capacitor described in claim 7.

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

10. Controlling the upper limit of the thickness dimension of the film deposited on the metal mask according to any one of claims 1 to 6 to be 15 μm, When the thickness dimension of the deposited film reaches the upper limit, the metal mask is cleaned. A method for controlling a metal mask used for forming internal electrodes in a multilayer ceramic capacitor, including the method described above.

Images