Manufacturing method for multilayer films
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOHOKU UNIV
- Filing Date
- 2025-01-22
- Publication Date
- 2026-08-03
Smart Images
Figure 2026125540000001_ABST
Abstract
Description
[Technical Field]
[0001] This invention relates to a method for manufacturing a multilayer film. [Background technology]
[0002] Multilayer films are one example of multilayer electronic components. Well-known examples of multilayer electronic components include multilayer ceramic capacitors, multilayer inductors, and low-temperature co-fired ceramic substrates (LTCC). The manufacturing of multilayer electronic components is complex. [Prior art documents] [Patent Documents]
[0003] [Patent Document 1] Japanese Patent Publication No. 2020-017405 [Patent Document 2] Japanese Patent Publication No. 5-74651 [Overview of the project] [Problems that the invention aims to solve]
[0004] This document describes a multilayer ceramic capacitor, a type of multilayer electronic component. Figure 1A is an example of a perspective view of a multilayer ceramic capacitor, and Figure 1B is a schematic diagram showing the cross-sectional structure of a multilayer ceramic capacitor. A multilayer ceramic capacitor comprises a laminate 10 in which dielectric layers 12 and internal electrode layers 11 are alternately stacked, and an external electrode 20. As shown in Figure 1B, the external electrode 20 comprises an external electrode layer 21 and a plating layer 22, and the external electrode layer 21 is electrically connected to the internal electrode layer 11. The dielectric layer 12 is formed of a dielectric material such as barium titanate (BaTiO3), the internal electrode layer 11 is formed of a metal such as nickel, and the external electrode layer 21 is formed of a cured product of a mixture of metal powders such as silver powder and resin such as epoxy resin, in addition to metals such as nickel and copper.
[0005] Multilayer ceramic capacitors are manufactured as follows: First, a conductive paste for internal electrodes is applied to the surface of a green sheet containing dielectric powder such as barium titanate (BaTiO3) and a binder resin, using screen printing technology or similar methods to create a predetermined electrode pattern. The organic solvent contained in the conductive paste is removed by drying, forming a dry film. Next, the dry film and the green sheet are stacked alternately, heated and pressed together to form a laminate. This laminate is cut, subjected to organic binder removal treatment in an oxidizing or inert atmosphere, and then fired at a temperature of 1000°C to 1350°C for 0.5 hours to 8 hours to obtain a fired chip. Then, an external electrode paste is applied to both ends of the fired chip, fired or cured to form an external electrode layer, and finally, nickel plating or similar treatment is applied to the surface of the external electrode layer to obtain a multilayer ceramic capacitor. Generally, the conductive paste used to form the internal electrode layer contains conductive powder, ceramic powder, binder resin, and an organic solvent.
[0006] Patent Document 1 discloses a technology for a conductive paste containing conductive powder and an organic solvent that exhibits minimal viscosity changes over time. As a method for manufacturing multilayer ceramic capacitors without using conductive paste, the formation of internal electrodes by physical film deposition such as vapor deposition or sputtering is also being considered.
[0007] Patent Document 2 discloses a technique for manufacturing a multilayer ceramic capacitor by forming a thin film of a base metal such as copper, which will serve as the internal electrode, on a metal plate, transferring the thin film of the base metal formed on the metal plate to a green sheet, stacking the green sheets with the transferred base metal film in multiple layers and pressing them together, and then firing them (at 1000°C in Patent Document 2).
[0008] As mentioned above, the manufacture of multilayer ceramic capacitors requires the use of internal electrode paste with a special material composition and viscosity control over time, as described in Patent Document 1. However, there are storage and handling problems because the period during which the optimal viscosity can be maintained is short.
[0009] In the physical deposition of internal electrodes described in Patent Document 2, control of the viscosity of the internal electrode paste is unnecessary. However, the internal electrode deposition method in Patent Document 2 requires the extra step of depositing the film on another substrate and then transferring it, rather than depositing it directly on the green sheet, resulting in low productivity. The reason why Patent Document 2 cannot directly deposit a thin film of the base metal that will become the internal electrode onto the green sheet is that, unlike physical deposition, it is not possible to deposit a film of 0.5 × 10⁻⁶. -4 Under reduced pressure conditions like those in Torr, the green sheet substrate is likely to deteriorate due to the volatilization of organic components that provide flexibility to the green sheet. Furthermore, there are concerns that the gases produced by the volatilization of these organic components may alter the internal electrode film that has been deposited.
[0010] The object of the present invention is to provide a method for manufacturing laminates such as multilayer electronic components without the need for viscosity control as described in Patent Document 1 or complex transfer as described in Patent Document 2. [Means for solving the problem]
[0011] One aspect of the present invention is a method for manufacturing a laminated film, comprising: a misting step of atomizing a first dispersion containing first nanoparticles; a step of supplying the atomized first dispersion to a substrate to form a first film; a misting step of atomizing a second dispersion containing second nanoparticles; and a step of supplying the atomized second dispersion onto the first film to form a second film, wherein the second nanoparticles are metal particles.
[0012] Another aspect of the present invention is a method for manufacturing a laminated film, comprising: a misting step of atomizing a second dispersion containing second nanoparticles; a step of supplying the atomized second dispersion onto a ceramic green sheet to form a second film; a misting step of atomizing a first dispersion containing first particles; and a step of supplying the atomized first dispersion onto the second film to form a first film, wherein the second nanoparticles are metal particles.
[0013] Another aspect of the present invention is a method for manufacturing a laminated film, which includes repeatedly performing a misting step of atomizing a second dispersion liquid in which second nanoparticles that are metal particles are dispersed, a step of supplying the atomized second dispersion liquid to a first ceramic green sheet to form a second film, and a step of covering the second film with a second ceramic green sheet.
Brief Description of the Drawings
[0014] [Figure 1] FIG. 1A is an example of a perspective view of a multilayer ceramic capacitor. FIG. 1B is a schematic diagram showing a cross-sectional structure of the multilayer ceramic capacitor. [Figure 2] A diagram showing an example of a metal mask for forming a pattern. [Figure 3] A conceptual diagram showing an example of a mist coating apparatus in the present embodiment. [Figure 4] An SEM (Scanning Electron Microscope) image of a cross-section of a laminated film manufactured by the method for manufacturing a laminated film according to the present embodiment. [Figure 5] A graph showing an EDS (Energy dispersive X-ray spectroscopy) analysis (in the film thickness direction) of a laminated film manufactured by the method for manufacturing a laminated film according to the present embodiment. <0
[0017] <Method for manufacturing multilayer films> One method for manufacturing a laminated film according to this embodiment includes a misting step of atomizing a first dispersion containing first nanoparticles, a step of supplying the atomized first dispersion to a substrate to form a first film, a misting step of atomizing a second dispersion containing second nanoparticles, and a step of supplying the atomized second dispersion onto the first film to form a second film. The second nanoparticles are metal particles.
[0018] Another method for manufacturing the laminated film according to this embodiment includes a misting step of atomizing a second dispersion containing second nanoparticles, a step of supplying the atomized second dispersion to a ceramic green sheet to form a second film, a misting step of atomizing a first dispersion containing first nanoparticles, and a step of supplying the atomized first dispersion onto the second film to form a first film. The second nanoparticles are metal particles.
[0019] Another method for manufacturing a laminated film according to the present invention involves repeatedly performing the following steps: a misting step of atomizing a second dispersion in which a second nanoparticle, which is a metal particle, is dispersed; a step of supplying the atomized second dispersion onto a first ceramic green sheet to form a second film; and a step of covering the second film with a second ceramic green sheet.
[0020] The substrate can be a plate-shaped substrate such as a glass substrate, plastic substrate, or metal substrate, or a flexible substrate such as a resin film, and its shape is not particularly limited. Furthermore, the substrate may be subjected to a treatment to make it more hydrophilic to the mist, such as by plasma irradiation.
[0021] Furthermore, the ceramic green sheet mentioned above is a sheet formed from a mixture containing dielectric powder such as barium titanate, soft magnetic powder such as ferrite, or ceramic powder such as alumina or zirconia, and a binder resin. In addition, by adjusting the type of binder resin and its mixing ratio, the green sheet itself may be made hydrophilic to mist. For example, polyvinyl butyral resin, which is often used as a binder resin, allows for control of its hydrophilicity to mist by adjusting the amount of butyral and acetyl groups, depending on the degree of butyralization introduced to the OH groups of the raw material polyvinyl alcohol.
[0022] The thickness of the substrate is 10 μm or more and 10 mm or less. When flexibility is required in the substrate, the lower limit of the thickness is preferably 10 μm, more preferably 50 μm, and even more preferably 100 μm. The upper limit of the substrate thickness is preferably 10 mm, more preferably 1 mm, and even more preferably 500 μm.
[0023] In the method for manufacturing a laminated film according to this embodiment, a two-layer formation process, which includes the steps of forming a first film and forming a second film, is performed two or more times to form an alternating laminate.
[0024] If the substrate is a ceramic green sheet containing dielectric powder such as barium titanate and a binder resin, the second film can be formed on the substrate without forming the first film, and then the subsequent two-layer formation can be carried out to form an alternating laminate. In this case, the top layer will be the first film. If the top layer is to be conductive, the second film can be formed on the top layer after the two-layer formation is completed.
[0025] The number of layers in the laminate after film formation is four or more, with a lower limit of preferably four layers, more preferably ten layers, and even more preferably 100 layers. The upper limit of the number of layers in the laminate may exceed, for example, 1000 layers.
[0026] The method for manufacturing a laminated film according to this embodiment may include a step of drying the first film at 100°C or below. By drying the first film, deterioration of the first film can be prevented when the second film is subsequently formed. The upper limit of the temperature in the step of drying the first film is preferably 100°C, more preferably 80°C, and even more preferably 60°C. The lower limit of the temperature in the step of drying the first film is, for example, 0°C.
[0027] The method for manufacturing the laminated film according to this embodiment may include a step of drying the second film at 100°C or below. By drying the second film, deterioration of the second film can be prevented during the formation of the first film that is subsequently formed or during the installation of the ceramic green sheet. The upper limit of the temperature in the step of drying the second film is preferably 100°C, more preferably 80°C, and even more preferably 60°C. The lower limit of the temperature in the step of drying the second film is, for example, 0°C.
[0028] The first nanoparticles are inorganic particles containing dielectric materials such as barium titanate and other ferroelectric materials, soft magnetic materials such as ferrite, and ceramic powder materials such as alumina and zirconia. If a multilayer ceramic capacitor is to be formed as a laminate, dielectric materials are used for the inorganic particles. If an inductor is to be formed as a laminate, soft magnetic materials are used for the inorganic particles. If an LTCC is to be formed as a laminate, alumina or zirconia are used. Furthermore, sintering aids and known additives may be added to control the sinterability and properties of the inorganic material.
[0029] Hereafter, the present invention will be explained using an example of forming a laminated structure of a multilayer ceramic capacitor.
[0030] The average particle size of the first nanoparticles is between 1 nm and 500 nm. The lower limit is preferably 1 nm, more preferably 5 nm, and even more preferably 10 nm. The upper limit is preferably 500 nm, more preferably 300 nm, and even more preferably 100 nm.
[0031] The average particle size of the first nanoparticles refers to the number-average particle size obtained from scanning electron microscope (SEM) images of nickel powder. Specifically, the average particle size of the first nanoparticles is obtained, for example, by processing the SEM images to measure the area of each individual first nanoparticle, calculating the diameter of each first nanoparticle from that area in terms of a perfect circle, and then calculating the average value. In this case, the average particle size is the number-average particle size.
[0032] The content of the first nanoparticles in the first dispersion is 0.1% or more and 50% or less by mass. The lower limit is preferably 0.1%, more preferably 1%, and even more preferably 3%. The upper limit is preferably 50%, more preferably 30%, and even more preferably 10%.
[0033] The second nanoparticles are gold, silver, platinum, palladium, copper, nickel, etc. If the laminate is a multilayer ceramic capacitor, the second nanoparticles are preferably palladium, copper, or nickel, with nickel being more preferable.
[0034] The average particle size of the second nanoparticle is between 1 nm and 500 nm. The lower limit is preferably 1 nm, more preferably 5 nm, and even more preferably 10 nm. The upper limit is preferably 500 nm, more preferably 300 nm, and even more preferably 100 nm.
[0035] The average particle diameter of the second nanoparticles refers to the number-average particle diameter obtained from scanning electron microscope (SEM) images of nickel powder. Specifically, the average particle diameter of the second nanoparticles is obtained, for example, by processing the SEM images to measure the area of each second nanoparticle, calculating the diameter of each second nanoparticle by converting the area to a perfect circle, and then calculating the average value. The average particle diameter here is the number-average particle diameter.
[0036] The content of the second nanoparticles in the second dispersion is 0.1% or more and 50% or less by mass. The lower limit is preferably 0.1%, more preferably 1%, and even more preferably 3%. The upper limit is preferably 50%, more preferably 30%, and even more preferably 10%.
[0037] The solvents used in the first dispersion and the second dispersion in the method for manufacturing a laminated film according to this embodiment are polar solvents such as water and water-soluble organic solvents, for example methanol, ethanol, 1-propanol, toluene, and acetone. These solvents may be used individually or in combination of two or more. The solvents contained in the first dispersion and the second dispersion may be the same or different.
[0038] In the method for manufacturing a laminated film according to this embodiment, the first dispersion and the second dispersion may each contain organic additives to obtain a homogeneous slurry. The organic additives contained in the first dispersion and the second dispersion may be the same or different.
[0039] The organic additive in this embodiment is a quaternary ammonium hydroxide. Quaternary ammonium hydroxide has the general formula: [R 1 , R 2 , R 3 , R 4 N + ][OH - It has the composition represented by [ ]. In the general formula, R represents an alkyl group.
[0040] Quaternary ammonium hydroxides almost completely dissociate in aqueous solution, simultaneously producing hydroxyl ions and ammonium ions. The hydroxyl ions raise the pH of the aqueous solution to the alkaline side, i.e., pH 7 or higher, and nickel and Ba under acidic atmospheres. 2+It becomes possible to suppress the progress of aggregation due to elution. Further, by interposing a quaternary ammonium ion charged between the particles constituting the nickel or barium titanate powder, the aggregability of the first nanoparticles and the second nanoparticles is alleviated, and it becomes possible to facilitate the disintegration treatment.
[0041] In order to effectively exhibit such an effect, it is preferable that it has a high degree of dissociation in an aqueous solution and at the same time the length of the alkyl group is such that the action of the positive charge of the nitrogen atom is not inhibited by steric hindrance.
[0042] From this point of view, the number of carbon atoms of the quaternary ammonium hydroxide is preferably 16 or less. When the number of carbon atoms is in the range of 4 or more and 16 or less, due to the synergistic effect of the formation of an alkaline environment in an aqueous solution and the interposition of charged quaternary ammonium ions between particles, the aggregability of barium titanate particles in the first dispersion and the second dispersion is significantly alleviated. Therefore, even if the addition amount of the quaternary ammonium hydroxide with respect to the total amount of the solvent is very small, it becomes possible to provide the first dispersion and the second dispersion with easy disintegration properties.
[0043] General formula representing quaternary ammonium hydroxide: [R 1 , R 2 , R 3 , R 4 N + [OH - In this formula, R 1 , R 2 , R 3 , R 4 are each preferably an alkyl group having 1 or more and 4 or less carbon atoms, and are preferably composed of the same or different alkyl groups from each other.
[0044] Examples of quaternary ammonium hydroxides with such a structure include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylpropylammonium hydroxide, dimethyldipropylammonium hydroxide, monomethyltriethylammonium hydroxide, and monomethyltripropylammonium hydroxide. These quaternary ammonium hydroxides may be used individually or in combination of two or more.
[0045] For reasons unknown, among these, those in which the charge is easily distributed isotropically when ionized in a solvent are preferred. More specifically, the quaternary ammonium hydroxide is preferably at least one selected from tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.
[0046] The content of the organic additive in the first dispersion is 0.01% or more and 3.0% or less by mass. The lower limit of the content of the organic additive in the first dispersion is preferably 0.1%. The upper limit of the content of the organic additive in the first dispersion is preferably 1.0%.
[0047] The content of the organic additive in the second dispersion is 0.01% or more and 3.0% or less by mass. The lower limit of the content of the organic additive in the second dispersion is preferably 0.1%. The upper limit of the content of the organic additive in the second dispersion is preferably 1.0%.
[0048] The thickness of the first film is 0.1 μm or more and 10 μm or less. The lower limit of the thickness of the first film is preferably 0.1 μm, more preferably 0.2 μm, and even more preferably 0.3 μm. The upper limit of the thickness of the first film is preferably 10 μm, more preferably 1 μm, and even more preferably 0.5 μm. When layered, the thickness of each first film may be different as long as they are within these numerical ranges.
[0049] The thickness of the second film is 0.1 μm or more and 10 μm or less. The lower limit of the thickness of the second film is preferably 0.1 μm, more preferably 0.2 μm, and even more preferably 0.3 μm. The upper limit of the thickness of the second film is preferably 10 μm, more preferably 2 μm, even more preferably 1 μm, and even more preferably 0.5 μm. When layered, the thicknesses of each second film may be different as long as they remain within these numerical ranges.
[0050] The thickness of the second film in this embodiment can be reduced to 2 μm or less, which is difficult to achieve with screen printing. In multilayer electronic components, it is necessary to reduce the thickness of the second film, which serves as the internal electrode, when stacking multiple layers. The second film is formed with an internal electrode pattern, while the first film is formed as a flat surface without a pattern. If the second film is formed to a thickness of more than 10 μm, there is a risk that a convex step corresponding to the shape of the pattern of the first film will be formed on the second film, which is formed to cover the surface of the first film when forming a multilayer film as described later. Such a step can make it difficult to form the multilayer film. Therefore, the thickness of the second film is reduced.
[0051] The multilayer film of this embodiment can be used in multilayer ceramic capacitors, LTCCs, multilayer inductors, etc. The first film and ceramic green sheet can be a dielectric layer in multilayer ceramic capacitors, a layer containing alumina or zirconia in LTCCs, and a soft magnetic layer in multilayer inductors. The second film can be an internal electrode layer in any of the cases of multilayer ceramic capacitors, LTCCs, or multilayer inductors.
[0052] <Procedure for film formation using mist> Figure 3 shows an example of a mist deposition apparatus 2 that can be used in a method for manufacturing a laminated film according to this embodiment. The mist deposition apparatus 2 comprises a mist generating unit 110 and a deposition unit 120. The dispersion 100 contains nanoparticles P homogeneously dispersed in a solvent L. The mist generating unit 110 atomizes the dispersion 100. The deposition unit 120 deposits the mist M of the dispersion 100 onto the object to be deposited 122. The mist generating unit 110 and the deposition unit 120 are connected via piping 116.
[0053] The mist generating unit 110 includes an outer container 111, an inner container 112, a lid 113, a gas supply pipe 114, and an ultrasonic transducer 115. The outer container 111 is a container that houses the propagating liquid, the inner container 112, and the ultrasonic transducer 115. The outer container 111 houses the inner container 112 and the propagating liquid such that at least a portion of the inner container 112 is in contact with the propagating liquid.
[0054] The inner container 112 contains the dispersion liquid 100 which will be the material for the mist M. The lid 113 is installed at the opening at the top of the inner container 112. The mist generating unit 110 does not necessarily have to have a lid 113.
[0055] The gas supply pipe 114 delivers the carrier gas G, which carries the mist M, into the inner container 112. The gas supply pipe 114 is attached to the top or lid 113 of the inner container 112. The position and configuration of the gas supply pipe 114 are not particularly limited, and it is sufficient if it is configured to supply the carrier gas into the inner container 112.
[0056] The ultrasonic transducer 115 generates vibrations. The vibrations generated by the ultrasonic transducer 115 are transmitted to the dispersion liquid 100 in the inner container 112 by the propagation liquid. The installation position of the ultrasonic transducer 115 is not limited; any structure that allows the vibrations of the ultrasonic transducer 115 to be transmitted to the dispersion liquid 100 is acceptable. When the vibrations of the ultrasonic transducer 115 are transmitted to the dispersion liquid 100, the mist generating unit 110 does not need to have an outer container 111 and a propagation liquid. In addition, any transducer that generates mist M can be used as the ultrasonic transducer 115, and it may not even be an ultrasonic transducer. As a result, ultrasonic vibrations are applied to the dispersion liquid 100 by the vibrations of the ultrasonic transducer 115.
[0057] The output and frequency of the ultrasonic transducer 115 that generates mist M can be set as appropriate. The frequency can be, for example, 1.0 MHz to several MHz. The output can be, for example, 10 W to 200 W.
[0058] The film deposition unit 120 comprises a housing 121, a temperature control device (not shown in the figure), and a stage (not shown in the figure). The housing 121 is a wall separating the film deposition unit 120 from the outside. The temperature control device (not shown in the figure) adjusts the temperature of the object to be deposited 122. The stage (not shown in the figure) holds the object to be deposited 122. The object to be deposited 122 can be a glass substrate, a plastic substrate, a metal substrate, etc., and the material is not particularly limited. Also, for example, the object to be deposited 122 can be a film or an object with a shape other than a flat plate, and the shape is not particularly limited.
[0059] In the method for manufacturing a laminated film according to this embodiment, when the first film is formed, the substrate or the second film becomes the object to be formed 122, and when the second film is formed, the substrate or the first film may become the object to be formed 122.
[0060] In the method for manufacturing a laminated film according to this embodiment, the first dispersion and the second dispersion are atomized, and the first film is deposited on the substrate, followed by the second film, in an alternating layered structure.
[0061] In other manufacturing methods of the laminated film according to this embodiment, the substrate and the first film deposited on the substrate can be replaced with a ceramic green sheet. Alternatively, the first film deposited on the second film can be replaced with a ceramic green sheet. For example, the second film may be deposited on the ceramic green sheet, followed by the first film, in alternating order. Alternatively, the operation of depositing the second film on the ceramic green sheet, placing another ceramic green sheet on top of it, and then depositing the second film on top of that may be repeated.
[0062] In this embodiment, mist M generated in the mist generation unit 110 is supplied to the film formation unit 120 via the piping 116. More specifically, vibrations from the ultrasonic transducer 115 are transmitted to the dispersion liquid 100 in the internal container 112 via the propagation liquid. The dispersion liquid 100 is atomized by the vibrations. The generated mist M is sent to the piping 116. Carrier gas G supplied from the gas supply pipe 114 is also sent to the piping 116. The piping 116 transports the mist M and carrier gas G from the mist generation unit 110 to the film formation unit 120.
[0063] The mist M, which reaches the film deposition section 120 via the piping 116, arrives at the object to be deposited on 122 and forms a mist film.
[0064] Furthermore, the configuration of the mist deposition apparatus 2 is not limited to the example shown in Figure 3. For example, a mist containment tank for capturing excess mist may be provided between the mist generation unit 110 and the deposition unit 120, or a sensor for detecting the flow rate of mist passing through the piping 116 may be provided.
[0065] Furthermore, the film formation method for the laminated film of this embodiment involves forming the first film and the second film two or more times to create an alternating laminate and thus a multilayer film.
[0066] In the film deposition method of this embodiment, 0.5 × 10 -4Since the process is not carried out under a reduced-pressure atmosphere like Torr, the ceramic green sheet is not altered. Therefore, even if the ceramic green sheet and the first film are laminated alternately, a multilayer film similar to that formed when the first and second films are deposited two or more times to create an alternating laminate can be obtained.
[0067] When forming the second film, a metal mask as shown in Figure 2 may be used to form the pattern. Once the second film has been patterned, it can be cut so that the longitudinal edges of the pattern are not exposed, and then sintered at the temperature at which the ceramics constituting the first film and clean sheet are sintered to form a multilayer ceramic capacitor.
[0068] Furthermore, if the pattern in Figure 2 is used as the wiring circuit pattern and alumina or zirconia is used as the ceramic, an LTCC can be formed. If a soft magnetic material is used instead of ceramic and the pattern is made to form a coil, a multilayer inductor can be formed. [Examples]
[0069] The method for manufacturing a laminated film according to this embodiment will be specifically described by the following examples, but the present invention is not limited to these examples.
[0070] <Preparation of dispersion 100> Nickel slurry A 97% by mass aqueous solution was prepared by adding tetraethylammonium hydroxide to water used as a solvent, while measuring the pH at a liquid temperature of 25°C using a pH meter, until the pH reached 12. 3% by mass of nickel powder (M-T-60, manufactured by Sumitomo Metal Mining Co., Ltd.) with an average particle size of 60 nm was mixed with this solution, and the mixture was subjected to crushing treatment using a thin-film swirling high-speed mixer (Primix Corporation, Filmix 30-L type) to prepare a 3% by mass nickel slurry. The amount of tetraethylammonium hydroxide added to the water was 17 mmol / L.
[0071] Barium titanate slurry A 97% by mass aqueous solution was prepared by adding tetraethylammonium hydroxide to water used as the solvent, while measuring the pH at a liquid temperature of 25°C using a pH meter, until the pH reached 12. 3% by mass of barium titanate powder (T-BTO-010RF, manufactured by Toda Kogyo Co., Ltd.) with an average particle size of 30 nm was then mixed with this solution, and the mixture was subjected to a crushing treatment using a thin-film swirling high-speed mixer (Primix Corporation, Filmix 30-L type) to prepare a 3% by mass nickel slurry. The amount of tetraethylammonium hydroxide added to the water was 17 mmol / L.
[0072] <Mist film formation> Formation of the first film 40 mL of the dispersion 100 (barium titanate slurry) prepared above was placed in the internal container 112 of the mist deposition apparatus 2. An ultrasonic transducer 115 was placed in an external container 111 containing cooling water, and the internal container 112 containing the dispersion 100 was placed inside it. A lid 113 was placed over the internal container 112, and a gas supply pipe 114 was inserted through one of the two holes in the lid 113. Dry air, which would become the carrier gas G, was supplied from the gas supply pipe 114 at a rate of 9 L / min. A pipe 116 was inserted through the other hole, and mist M was transported to the deposition section 120.
[0073] During the transport of mist M, the film-forming object 122 (silicon wafer substrate) placed on the stage was temperature-controlled by placing it on a heat sink connected to a cooling water circulation device (Tokyo Rikakikai CA-1320). The temperature control device controlled the temperature of the film-forming object 122 to 18°C. The mist M transported to the film-forming section 120 was blown onto the film-forming object 122 placed on the stage, and a mist film was formed. After generating the mist M, the formation of the mist film continued for 1 minute from the time the carrier gas G was inflow. Then, dry air was blown on for 120 seconds to dry it, and this process was repeated 5 times to obtain the first film.
[0074] Deposition of the second film 40 mL of the dispersion 100 (nickel slurry) prepared above was placed in the internal container 112 of the mist film deposition apparatus 2. An ultrasonic transducer 115 was placed in an external container 111 containing ice water, and the internal container 112 containing the dispersion 100 was placed inside it. A lid 113 was placed over the internal container 112, and a gas supply pipe 114 was inserted through one of the two holes in the lid 113. Dry air, which would become the carrier gas G, was supplied from the gas supply pipe 114 at a rate of 9 L / min. A pipe 116 was inserted through the other hole, and mist M was transported to the film deposition section 120.
[0075] During the transport of mist M, the object to be deposited 122 (the first film obtained above), which was placed on the stage, was temperature-controlled by placing it on a heat sink connected to a cooling water circulation device (Tokyo Rikakikai CA-1320). The temperature control device controlled the temperature of the object to be deposited 122 (the first film obtained above) to 18°C. The mist M transported to the deposition section 120 was blown onto the object to be deposited 122 placed on the stage, and a mist film was formed. After generating the mist M, the formation of the mist film was continued for 1 minute from the time the carrier gas G was inflow. Then, dry air was blown on for 120 seconds to dry it, and this process was repeated 5 times to obtain a second film.
[0076] The process of depositing the first film and the second film was repeated three times to produce a total of six layered films. It was confirmed that the multilayer film manufactured by the method of this embodiment can be formed with a thickness of 100 nm to 200 nm per layer.
[0077] Figure 4 is a Scanning Electron Microscope (SEM) image of a cross-section of the multilayer film manufactured by the above method. Figure 5 is a graph showing the Energy Dispersive X-ray Spectroscopy (EDS) analysis (film thickness direction) of the multilayer film manufactured by the above method.
[0078] Figures 4 and 5 confirm the thinning of each layer. [Explanation of Symbols]
[0079] 1. Multilayer ceramic capacitor 10-Laminate 11...Internal electrode layer 12. Dielectric layer 20...External electrode 21...External electrode layer 22. Plating layer 2. Mist deposition apparatus 100...Dispersion liquid 110...Mist generating unit 111... External container 112...Inner container 113...lid 114...Gas supply pipe 115... Ultrasonic transducer 116... Piping 120...Film forming section 121... cabinet 122... Objects to be deposited G... Carrier gas M... Mist L...solvent P... nanoparticles
Claims
1. A misting step in which a first dispersion containing the first nanoparticles is atomized, A step of supplying the atomized first dispersion to a substrate to form a first film, A misting step in which a second dispersion containing a second nanoparticle is atomized, A method for manufacturing a laminated film, comprising the steps of supplying the atomized second dispersion onto the first film to form a second film, wherein the second nanoparticles are metal particles.
2. A misting step in which a second dispersion containing a second nanoparticle is atomized, The process involves supplying the atomized second dispersion onto a ceramic green sheet to form a second film, A misting step in which a first dispersion containing the first nanoparticles is atomized, A method for manufacturing a laminated film, comprising the steps of supplying the atomized first dispersion onto the second film to form the first film, wherein the second nanoparticles are metal particles.
3. A method for manufacturing a laminated film according to claim 1 or 2, comprising performing two or more steps of forming a second film, including the step of forming the first film and the step of forming the second film, to form an alternating laminate.
4. A misting process in which a second dispersion containing second nanoparticles, which are metal particles, is atomized, The process involves supplying the atomized second dispersion onto the first ceramic green sheet to form a second film, A method for manufacturing a laminated film, comprising repeatedly performing the step of covering the second film with a second ceramic green sheet.
5. A method for manufacturing a laminated film according to any one of claims 1 to 3, comprising the step of drying the first film at 100°C or below.
6. A method for manufacturing a laminated film according to any one of claims 1 to 5, comprising the step of drying the second film at 100°C or below.
7. The method for producing a laminated film according to any one of claims 1 to 3, wherein the first nanoparticles include Ti.
8. The method for producing a laminated film according to claim 7, wherein the first nanoparticle is barium titanate.
9. The method for producing a laminated film according to any one of claims 1 to 8, wherein the second nanoparticle contains Ni.
10. The method for producing a laminated film according to any one of claims 1 to 3, wherein the first dispersion is a slurry containing water or a water-soluble organic solvent.
11. The method for producing a laminated film according to any one of claims 1 to 10, wherein the second dispersion is a slurry containing water or a water-soluble organic solvent.
12. The method for producing a laminated film according to claim 10 or 11, wherein the water-soluble organic solvent is an alcohol or ketone having 3 or fewer carbon atoms.
13. The method for producing a laminated film according to any one of claims 1 to 3, wherein the first dispersion contains an organic additive in an amount of 0.01% or more and 3.0% or less by mass.
14. The method for producing a laminated film according to any one of claims 1 to 13, wherein the second dispersion contains an organic additive in an amount of 0.01% or more and 3.0% or less by mass.