JP5177036B2 - Capacitor, structure, and method of manufacturing capacitor - Google Patents

Description

  The present invention relates to a capacitor, a structure, and a manufacturing method thereof.

  Capacitors include, for example, decoupling capacitors for suppressing noise generated by electronic devices, coupling capacitors for eliminating the difference in DC potential between electronic devices, and electronic components as components of filters. It is an indispensable part. In recent years, there is a remarkable reduction in the size of electronic devices, but the demand for downsizing of capacitors is also increasing in accordance with the downsizing of electronic devices.

  Examples of capacitors suitable for miniaturization include ceramic capacitors and aluminum electrolytic capacitors. Since these capacitors have a large capacity per unit volume, they can maintain a large capacity even if they are miniaturized.

  In a ceramic capacitor, a dielectric layer is formed of a ferroelectric such as barium titanate, and a necessary capacity is ensured (for example, Patent Document 1). In a multilayer ceramic capacitor having a larger capacity ceramic capacitor, electrodes and dielectric layers are alternately stacked. On the other hand, in the aluminum electrolytic capacitor, the surface area of the anode foil is increased by roughening, and a large capacity is realized.

Japanese Patent Laid-Open No. 5-47589

  However, any capacitor requires a complicated and precise manufacturing process in order to increase the capacity. For this reason, if it is going to enlarge these capacitors, manufacturing cost will become high.

  Therefore, an object of the present invention is to provide a large-capacity capacitor that can be formed by a simple and inexpensive manufacturing process, a structure used for forming such a large-capacity capacitor, and a method for manufacturing the same.

  In order to achieve the above object, a plurality of first conductor particles whose entire surface is covered with a first dielectric film are included, and the plurality of first conductor particles are mutually connected by the first dielectric film. A first insulating layer that is isolated, a first electrode that is in contact with a first main surface of the first insulating layer, and a second electrode that is formed of a dielectric and that the first insulating layer has. Provided is a capacitor including a second insulating layer in contact with a main surface and a second electrode in contact with the second insulating layer.

  According to this capacitor, a large-capacity capacitor that can be formed by a simple and inexpensive manufacturing process can be provided.

It is the figure which represented the characteristic of the image which adhered the Al powder by which the surface was covered with the aluminum oxide on the aluminum foil by the gas deposition method, formed the deposited film, and observed the cross section with the transmission electron microscope. It is a schematic diagram explaining the cross-sectional structure of the conductor particle before deposition by which the surface was covered with the dielectric film. An example of an image obtained by observing a cross-section of a deposited film formed by a gas deposition method using a mixed powder of Al powder and barium titanate (BaTiO ₃ ) particles whose surface is covered with aluminum oxide, using a transmission electron microscope It is a figure explaining. It is a conceptual diagram explaining the structure of a capacitor which uses the deposited film demonstrated with reference to FIG. 3 as a dielectric layer. It is a figure explaining the relationship between the proof pressure of a capacitor, and leakage current. FIG. 5 is a diagram for explaining a mechanism in which breakdown occurs in the capacitor described with reference to FIG. 4 (No. 1). FIG. 5 is a diagram for explaining another mechanism by which breakdown occurs in the capacitor described with reference to FIG. 4 (part 2). It is a conceptual diagram explaining the structure of the capacitor which this inventor first examined in order to improve a proof pressure. FIG. 3 is a cross-sectional view illustrating a configuration of the entire capacitor of Example 1. FIG. 3 is a diagram illustrating a cross section of the capacitor body of Example 1. It is sectional drawing explaining the manufacturing process of a barium titanate layer and a capillary membrane. It is sectional drawing explaining the formation process of an upper electrode. It is the table | surface (Table 1) in which the data regarding the Examples 1-4 (the structure of a dielectric layer and the characteristic at the time of making into a capacitor) were put together. It is the table | surface (Table 2) on which the data regarding the Examples 5-8 (structure of a dielectric material layer and the characteristic at the time of making into a capacitor) were summarized. It is the table | surface (Table 3) on which the data regarding the comparative example and the data of the conventional capacitor with which the structure except a dielectric material layer were similar to the capacitor of each Example were summarized. It is an equivalent circuit of the capacitor of Comparative Example 2 in which a barium titanate layer is formed both between the capillary film and the lower electrode and between the capillary film and the upper electrode. 2 is an equivalent circuit of a capacitor according to the first embodiment. 2 is a cross-sectional view illustrating a configuration of a structure according to Embodiment 1. FIG. It is a figure explaining the structure of the gas deposition apparatus which this inventor has used. It is sectional drawing explaining the outline | summary of the capacitor of the present Example 2. FIG. 6 is a cross-sectional view illustrating an outline of a capacitor of Example 3. FIG. 6 is a cross-sectional view illustrating an outline of a capacitor of Example 4. FIG. 10 is a cross-sectional view illustrating a configuration of a capacitor according to Example 5. FIG. It is sectional drawing explaining the structure of a capacitor film.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited to these embodiments, but extends to the matters described in the claims and equivalents thereof. In addition, the same code | symbol is attached | subjected to the corresponding part even if drawings differ, and the description is abbreviate | omitted.

(1) Capacitor Formation Using Gas Deposition Method (i) Capacity A film forming method (hereinafter referred to as a gas deposition method) in which a powder in which particles are aggregated is jetted together with a gas and fixed to a substrate is simple and simple. This is an inexpensive film formation method. The gas deposition method is also a unique film forming method that enables a ceramic film having a film forming temperature exceeding 1000 ° C. to be formed at room temperature.

  The inventor has long studied this gas deposition method.

  In the process, the present inventor forms a metal film by a gas deposition method using conductive particles whose surface is covered with a dielectric film (for example, Al particles whose surface is oxidized) as a raw material powder, and the structure and The physical properties were examined.

  In the gas deposition method, the particles are accelerated by the gas at a speed higher than the sound velocity and violently collide with the substrate. The particles are fixed to the substrate by the impact at that time, and a thick film is formed.

  At this time, the particles fixed to the substrate are deformed so as not to stop the original shape due to the impact at the time of collision. Therefore, it was unclear whether the dielectric film covering the surface of the conductor particles covered the surface of the conductor particles even after the collision, or whether the conductor particles fixed through the dielectric film.

  In this regard, researchers involved in gas deposition believe that, upon impact, the active new surface appears through an oxide film covering the particle surface, and the particles stick together.

  FIG. 1 shows the characteristics of an image obtained by forming a deposited film by fixing Al powder whose surface is covered with aluminum oxide on an aluminum foil by a gas deposition method, and observing a cross section of the deposited film with a transmission electron microscope. It is.

  The Al powder used to form the deposited film is a collection of Al particles having an average particle size of 3 μm ± 1 μm (the number after ± represents the standard deviation) whose surface is covered with aluminum oxide having a thickness of 10 to 100 nm. It is. Here, the details of the film forming conditions are the same as those of the first insulating layer 56 of Example 1 described later. Moreover, the average particle diameter of the Al particles is measured by a centrifugal sedimentation method (the same applies to the following description).

  FIG. 2 is a schematic diagram for explaining a cross-sectional structure of particles before deposition. As shown in FIG. 2, in the particles 2 forming the raw material powder, the entire surface of the conductor particles 4 (here, Al particles) is covered with a dielectric film 6 (here, aluminum oxide). Here, the shape of the particle 2 is substantially spherical.

  However, in the deposited film formed by the particles 2 colliding with the substrate, the Al particles 8 are greatly deformed as shown in FIG. On the other hand, the individual Al particles 8 are separated, and an aluminum oxide layer 10 is interposed between the particles. That is, even in the deposited film, the entire surface of the Al particles 8 (conductor particles) is covered with aluminum oxide (dielectric material).

  By the way, as shown in FIG. 1, the aluminum oxide 10 is stretched around the deposited film like a capillary blood vessel and separates the Al particles 8 (however, the aluminum oxide 10 is not a capillary but a conductor particle 10). Is a continuum of dielectric films interposed between the two). Therefore, the dielectric film that separates the conductor particles in this way is hereinafter referred to as a capillary.

  In addition, a complex formed by conductor particles (for example, Al particles 8) and capillaries (for example, aluminum oxide 10) as shown in FIG. 1 is hereinafter referred to as a capillary film.

  The film formation method described with reference to FIG. 1 and FIG. 2 is not based on a film formation mechanism that a new surface is exposed by a strong impact and particles are firmly adhered to each other as thought by researchers. . This film forming method utilizes the plasticity of the conductor (metal, etc.) of the particle core part, and the individual particles are plastically deformed to such an extent that the dielectric coating formed on the surface thereof is not destroyed. This is a film forming method based on a mechanism in which particles are integrated and fixed. That is, this film forming method can be said to be a film forming method using particles as a raw material and utilizing plastic deformation of a conductor.

  Next, the inventor examined the electrical characteristics of such a deposited film. As predicted from the structure in which the individual Al particles 8 are separated by the insulating aluminum oxide film 10, the deposited film has an extremely high resistance value and is insulative.

  Based on such a result, the present inventor has examined whether the deposited film can be used as a dielectric layer of a capacitor (an insulating layer disposed between the electrodes of the capacitor) as one method of utilizing the deposited film. It was decided to.

  Therefore, the present inventor first formed a metal electrode on the upper surface of the deposited film, produced a sample having the metal electrode as an upper electrode, and a substrate made of aluminum foil as a lower electrode, and produced a capacity per unit area. (Capacity density) was measured. The deposited film has a thickness of 250 μm.

The capacitance density obtained as a result of the measurement was an extremely high value of 30 μF / cm ² exceeding the capacitance density of the conventional capacitor. For example, even a ceramic capacitor in which barium titanate having a high dielectric constant is formed as a dielectric layer and the thickness of the dielectric layer is reduced to 1 μm has a capacitance density of only 2.5 μF / cm ² .

  The reason why the capacity density is increased in this way is considered to be because the adjacent Al particles 8 are capacitively coupled through the extremely thin aluminum oxide 10.

  Furthermore, the gas deposition method is a simple and inexpensive method for producing a thick film. Therefore, if a capacitor is manufactured using the deposited film formed by the gas deposition method as a dielectric layer, a large-capacity capacitor can be manufactured easily and inexpensively.

  Based on such knowledge, the present inventor decided to further study a capacitor using a deposited film formed by a gas deposition method as a dielectric layer.

Accordingly, the present inventor has studied various film forming conditions for further increasing the capacity density of the deposited film formed by the gas deposition method. As a result, it has been clarified that the capacitance density increases as the dielectric film 6 covering the surface of the conductor particle 4 becomes thinner. It was also found that when the dielectric particles having a high dielectric constant (for example, barium titanate (BaTiO ₃ ) particles) are mixed with the raw material powder, the capacity density of the deposited film is increased.

FIG. 3 shows a mixed powder of Al particles and barium titanate (BaTiO ₃ ) particles whose surfaces are covered with aluminum oxide as raw material powder, and a cross section of the deposited film formed by the gas deposition method was observed with a transmission electron microscope. It is an example of a tomogram. Here, the thickness of the aluminum oxide is 10 to 100 nm, and the particle size of the Al powder is 3 μm ± 1 μm. The particle diameter of the barium titanate particles is 100 nm. And the ratio of the barium titanate in the said mixed powder is 5% by volume ratio (it expresses like 5 vol% hereafter). The details of the film forming conditions are the same as those of the second insulating layer 58 of Example 1 described later.

As a result of the measurement, it was revealed that the capacity density of the deposited film was as extremely high as 100 μF / cm ² . At this time, the thickness of the deposited film is 10 μm.

  As shown in FIG. 3, the barium titanate particles 12 mixed with the raw material powder are taken into the deposited film in a state of being dispersed in a continuous body of aluminum oxide 10 covering the surface of the Al particles 8. In this example, a dielectric film (capillary) 14 formed of aluminum oxide 10 and barium titanate particles 12 separates Al particles 8.

  In the example shown in FIG. 3, the barium titanate particles 12 remain in the form of particles. However, the barium titanate particles 12 may be deformed without retaining the original shape to form a continuous film (hereinafter referred to as a continuous film). In particular, when the proportion of barium titanate increases, the barium titanate particles 12 are likely to form a continuous film. When such a deposited film is observed in detail, a continuous film made of barium titanate (hereinafter referred to as a barium titanate continuous film) exists between the Al particles 8 covered with the aluminum oxide film. In this case, the Al particles 8 are separated by a dielectric film (capillary) formed by an aluminum oxide film and a barium titanate continuous film.

  Barium titanate is a high dielectric constant material with a relative dielectric constant as high as 3000. When such a dielectric is interposed between the conductor particles (Al particles 8), the average dielectric constant of the dielectric film (capillary film) 14 increases. For this reason, it is considered that the capacitance density of the capacitor increases.

(Ii) Withstand Voltage FIG. 4 is a conceptual diagram (cross-sectional view) illustrating the configuration of the capacitor 18 using the deposited film described with reference to FIG. 3 as the dielectric layer 16. As shown in FIG. 4, the capacitor 18 includes a dielectric layer 16 formed by a gas deposition method, and an upper electrode 20 and a lower electrode 22 that sandwich the dielectric layer 16 from above and below.

  FIG. 4 shows a capacitor in which a deposited film in which Al particles 8 covered with an aluminum oxide film 24 are separated by a barium titanate continuous film 26 is used as a dielectric layer 16. However, the following description is also common to capacitors having a dielectric film (see FIG. 1) in which a dielectric film (capillary) 14 for isolating the Al particles 8 is formed of only aluminum oxide.

  In addition, the following description is common to a capacitor having a dielectric film as a dielectric film (capillary) 14 for isolating the Al particles 8 (see FIG. 1). The following description is also common to capacitors in which a film (see FIG. 3) in which barium titanate particles 12 are dispersed in a continuous film of aluminum oxide 10 covering the surface of Al particles 8 is used as a dielectric layer.

  As shown in FIG. 4, most of the dielectric layer 16 is occupied by Al particles 8 which are conductor particles. For this reason, when a voltage is applied to the capacitor 18, the electric field is applied to the dielectric film (capillary) 14 interposed between the Al particles 8. Therefore, the breakdown voltage of the capacitor 18 is determined by the resistance of the dielectric film (capillary) 14.

  The number of conductor particles forming the dielectric layer 16 is large and the shape is indefinite. It is difficult to illustrate such conductor particles. Therefore, in FIG. 4, the conductor particles are schematically represented. Similarly, in the following drawings, the conductor particles are schematically represented.

  FIG. 5 is a diagram for explaining the relationship between the withstand voltage of the capacitor and the leakage current. The horizontal axis is the voltage applied to the capacitor. The vertical axis represents the current flowing through the capacitor. When a voltage is applied to the capacitor, a small amount of leakage current 28 flows. However, as the voltage increases, a breakdown occurs at a certain point and the current increases rapidly. The voltage at which the current rapidly increases in this way is the withstand voltage 30.

  FIG. 6 is a diagram illustrating a mechanism in which breakdown occurs in the capacitor described with reference to FIG.

  As described above, almost all of the voltage applied to the capacitor 18 is applied to the thin dielectric film (capillary) 14 between the Al particles 8. When the voltage applied to the capacitor 18 is increased, breakdown occurs at the portion where the dielectric film (capillary) 14 is thinned, and a current path 32 (path through which current flows easily) is formed. For this reason, the breakdown voltage of the capacitor 18 becomes low.

  FIG. 7 is a diagram for explaining another mechanism in which breakdown occurs in the capacitor described with reference to FIG.

  As described above, the surface of the Al particles 8 in the deposited film is covered with the aluminum oxide film 24. However, it can be assumed that some Al particles are bonded to each other due to an impact during film formation. If such coupling occurs continuously, it is considered that the current path 32 is formed. Even in such a case, the breakdown voltage of the capacitor 18 becomes low.

  When the inventor evaluated the electrical characteristics of the capacitor 18, the withstand voltage was about 3V.

  This value is close to the withstand voltage of 5V of the electrolytic capacitor.

  However, it does not reach the withstand voltage 50V of the ceramic capacitor. Therefore, in order to put a capacitor having a deposited film formed by a gas deposition method as a dielectric layer into practical use, further improvement in breakdown voltage is desired.

(2) Improvement of breakdown voltage FIG. 8 is a conceptual diagram for explaining the configuration of a capacitor first examined by the present inventors in order to improve the breakdown voltage.

  The breakdown voltage of the capacitor 18 can be improved by increasing the thickness of the dielectric film (capillary) 14 interposed between the conductor particles (Al particles 8). However, when the dielectric film (capillary) 14 becomes thicker, the capacitance of the capacitor 18 decreases.

  Therefore, as shown in FIG. 8, the present inventor forms an insulating layer 34 formed of barium titanate between the deposited film (capillary film) 36 and the electrode 20 and between the deposited film (capillary film) 36 and the electrode. The capacitor 38 formed between 22 was examined.

  The structure of the deposited film (capillary film) 36 is the same as that of the dielectric layer 16 of the capacitor 18 described with reference to FIG. The insulating layer 34 is formed by a gas deposition method using barium titanate particles.

  As described above, the withstand voltage of the capacitor 18 described with reference to FIG. 4 is about 3V. On the other hand, the withstand voltage of the capacitor 38 reaches 20V. Thus, forming the insulating layer 34 between the deposited film (capillary film) 36 and the electrodes 20 and 22 is effective in improving the breakdown voltage.

  However, as described in Example 1 below, the insulating layer 34 is formed either between the lower electrode 22 and the deposited film (capillary film) 36 or between the upper electrode 20 and the deposited film (capillary film) 36. It is possible to improve the breakdown voltage simply by doing. Furthermore, according to such a configuration, the capacity density is also improved.

  In addition, as described in Example 2 below, by inserting an insulating layer formed of a dielectric material into the deposited film 36, it is possible to further improve the breakdown voltage.

  Hereinafter, these points will be described in accordance with examples.

(1) Configuration FIG. 9 is a cross-sectional view illustrating the overall configuration of the capacitor of this example.

  As shown in FIG. 9, the capacitor 40 has a capacitor body 44 including a first electrode (upper electrode 20), a dielectric layer 42, and a second electrode (lower electrode 22).

  In addition, the capacitor 40 includes a first lead electrode 46 connected to the upper electrode 20 and a second lead electrode 48 connected to the lower electrode 22.

  The capacitor 40 includes a case 50 (for example, a ceramic package) that stores the capacitor main body 44.

  FIG. 10 is a view for explaining a cross section of the capacitor main body 44.

  As shown in FIG. 10, the capacitor 40 (capacitor main body 44) includes a plurality of conductor particles 54 whose entire surface is covered with a dielectric film (capillary) 14, and the plurality of conductor particles 54 are composed of a dielectric film (capillary). ) 14 and the first insulating layer (capillary film) 56 separated from each other.

  The conductor particles 54 are, for example, Al particles 8. The dielectric film (capillary) 14 is formed by, for example, an aluminum oxide film 24 covering the surface of the Al particles 8 and a barium titanate continuous film 26 filling the space between the aluminum oxide films 24.

  Further, the capacitor 40 (capacitor main body 44) has a first electrode (upper electrode 20) in contact with the first main surface 62 of the first insulating layer 56.

  The capacitor 40 (capacitor main body 44) includes a second insulating layer 58 that is formed of a dielectric and has a third main surface 63 that is in contact with the second main surface 60 of the first insulating layer 56. doing.

Here, the dielectric is barium titanate. That is, the second insulating layer 58 is a titanium titanate layer. Here, barium titanate (BaTiO ₃ ) is an insulator as is well known. Note that the second insulating layer 58 is preferably formed only of a dielectric.

  The capacitor 40 (capacitor main body 44) has a second electrode (lower electrode 22) in contact with the fourth main surface 64 of the second insulating layer 58.

  Here, the thickness of the first insulating layer 56 (capillary film) is 53 μm. On the other hand, the thickness of the second insulating layer 58 (barium titanate layer 68) is 2 μm.

(2) Manufacturing Method Next, the configuration of the capacitor 44 will be described in detail according to the manufacturing process.

  FIG. 11 is a cross-sectional view for explaining a manufacturing process of the barium titanate layer 68 and the capillary film 70.

(I) Barium titanate layer forming step (see FIG. 11)
First, a barium titanate layer 68 (second insulating layer 58) having a thickness of 5 μm is deposited on an aluminum foil 66 having a thickness of 50 μm by a gas deposition method. The aluminum foil 66 eventually becomes the lower electrode 22.

  The deposition of the barium titanate layer 68 is performed according to the method described in “(5) Gas deposition method” below. The raw material powder is a powder in which barium titanate particles having an average particle diameter of 50 nm are aggregated. Although not particularly noted, also in the following description, the film formation by the gas deposition method is performed according to the method described in the following “(5) Gas Deposition Method”.

  The raw material powder is preferably formed only of dielectric particles.

(Ii) Capacitor film formation process (see FIG. 11)
Next, a capillary film 70 (first insulating layer 56) having a thickness of about 50 μm is deposited on the barium titanate layer 68 (second insulating layer 58) by a gas deposition method.

  The raw material powder is a mixed powder obtained by adding 5 vol% (volume ratio) of barium titanate particles to aluminum particles subjected to surface oxidation treatment. Here, the average particle diameter of the aluminum particles is 3 μm ± 1 μm. The average particle diameter of the barium titanate particles is 50 nm.

  Here, the surface oxidation treatment is a treatment in which the aluminum particles are heated in the atmosphere at 550 ° C. for 5 hours (the same applies to the following examples). By this surface oxidation treatment, about 5 nm of aluminum oxide thicker than the natural oxide film is formed on the entire surface of the aluminum particles. That is, the surfaces of the aluminum particles (conductor particles 4) are covered with aluminum oxide (dielectric film 6) (see FIG. 2).

  The conductor particles (Al particles) in the raw material powder adhere to the substrate and become conductor particles that form a capillary film. Therefore, the dielectric film (aluminum oxide film) and the barium titanate particles covering the surface of the conductor particles in the raw material powder form a capillary.

(Iii) Upper electrode formation process (see FIG. 12)
Next, the upper electrode 20 (first electrode) is formed.

  FIG. 12 is a cross-sectional view illustrating a process for forming the upper electrode 20.

  First, an Au film (not shown) serving as a seed electrode is deposited on the upper surface (the main surface 62 of the first insulating layer) of the capillary film 70 (first insulating layer 56) by an evaporation method. Thereafter, a photoresist film having an opening at a position where the upper electrode 20 is to be formed is formed on the seed electrode.

  Next, an Au plating layer is formed in the opening by electrolytic plating.

  Thereafter, the photoresist is removed, and the exposed Au film (deposited film) is removed by milling or chemical etching.

  By this step, the upper electrode 20 (first electrode) is completed.

(Iv) Lead wire formation and case storage process (see FIG. 9)
First, the first lead electrode 46 and the second lead electrode 48 are connected to the upper electrode 20 and the lower electrode 22, respectively.

  Next, the capacitor main body 44 provided with the first lead electrode 46 and the second lead electrode 48 is placed in an insulating case 50 (for example, a ceramic package), the first lead electrode 46 and the second lead electrode. The tip of 48 is stored so that it is exposed to the outside.

  With this step, the capacitor 40 is completed.

(3) Characteristics FIG. 13 shows a table (Table 1) that summarizes data (configuration and characteristics of dielectric layers) related to the present example and Examples 2 to 4 described later.

  FIG. 14 shows a table (Table 2) that summarizes data (configuration and characteristics of the dielectric layer) related to Examples 5 to 8 described later.

  FIG. 15 shows a table (Table 3) that summarizes data relating to a comparative example, which will be described later, and data of a conventional capacitor similar in configuration to the capacitor of each of the above embodiments except for the dielectric layer. For example, the configuration of the capacitor 40 of the present embodiment is similar to a conventional ceramic capacitor having a single dielectric layer except that the dielectric layer is formed of a capillary film. Therefore, in the fourth row of Table 3, data of the single layer ceramic capacitor is described.

  In the first column of Tables 1 to 3, the data described in each row is related to the capacitor of each example.

  In the second column, the basic structure and base material of each capacitor are described.

  In the third column, the configuration of the dielectric layer forming each capacitor is described. The configuration of each capacitor is represented by the type and thickness of the insulating layer forming each dielectric layer.

  The “capillary film” described in each row of the third column is formed by a gas deposition method using a mixed powder obtained by adding barium titanate particles to aluminum particles subjected to surface oxidation treatment as a raw powder. It is an insulating layer.

The “BaTiO ₃ layer” is a barium titanate layer formed by a gas deposition method using a powder in which barium titanate particles are aggregated as a raw material powder.

  In the fourth column, the thickness of the dielectric layer of each capacitor is described.

  In the fifth column, the capacitance density of each capacitor is described. However, the capacitance density of the multilayer capacitors of Examples 5 to 8 is converted per dielectric layer. The measurement frequency of the capacity density is 150 kHz.

  In the sixth column, the breakdown voltage of each capacitor is described.

As shown in the second row of Table 1, the capacitance density of the capacitor 40 of this example is 300 μF / cm ² . This value is much higher than the capacitance density 2.5 of the conventional ceramic capacitor (see the fourth row of Table 3). That is, according to the capacitor 40, a large-capacity capacitor can be formed by a simple and inexpensive gas deposition method.

  Incidentally, in the second row of Table 3, data relating to Comparative Example 1 below is described. The capacitor of Comparative Example 1 is a capacitor in which electrodes are directly formed on both the upper surface and the lower surface of a capillary film formed by a gas deposition method. The withstand voltage of this capacitor is as low as 3V.

  On the other hand, the withstand voltage of the capacitor 40 is 20 V (see the second row of Table 1). The reason why such a high breakdown voltage is obtained is that the barium titanate layer 68 (second insulating layer 58) formed between the lower electrode 22 and the capillary film 70 (first insulating layer 56) has a current path. It is because it prevents formation of.

  Incidentally, in the third row of Table 3, data relating to the capacitor of Comparative Example 2 below is described. The capacitor of Comparative Example 2 is a capacitor in which a barium titanate layer is formed not only between the capillary film 70 and the lower electrode 22 but also between the capillary film 70 and the upper electrode 20.

  The withstand voltage of the capacitor of Comparative Example 2 is 20V. This value is equal to the withstand voltage 20V of this capacitor.

  This result shows that the formation of a current path can be suppressed only by providing an insulating layer (for example, barium titanate layer 68) formed of a dielectric between the capillary film 70 and the lower electrode 22. On the other hand, the results of Example 2 to be described later indicate that the formation of a current path can be suppressed only by providing an insulating layer formed of a dielectric between the capillary film 70 and the upper electrode 20.

  These results show that the formation of a current path can be suppressed only by providing an insulating layer made of a dielectric material between the capillary film 70 and the upper electrode 20 and between the capillary film 70 and the lower electrode 22. Is shown.

Incidentally, the capacitance density of the capacitor of Comparative Example 2 is 200 μF / cm ² . This value is lower than the capacitance density of this capacitor, 300 μF / cm ² .

  This result shows that the capacity density can be increased by providing a single location for the insulating layer (for example, the barium titanate layer 68).

  The reason why the capacity density becomes high in this way can be explained as follows.

  FIG. 16 is an equivalent circuit of the capacitor of Comparative Example 2 in which a barium titanate layer is formed between the capillary film 70 and the lower electrode 22 and between the capillary film 70 and the upper electrode 20. FIG. 17 is an equivalent circuit of this capacitor.

  As shown in FIG. 16, the equivalent circuit of the capacitor of Comparative Example 2 is in contact with the equivalent circuit 74 corresponding to the barium titanate layer in contact with the lower electrode 22, the equivalent circuit 76 corresponding to the capillary film, and the upper electrode 20. An equivalent circuit 78 corresponding to the barium titanate layer is formed.

  Here, in the equivalent circuit 76 of the capillary film, the minute resistor 80 formed by the conductor particle 54 (Al particle 8) and the minute capacitor formed by the adjacent conductor particle 54 (Al particle 8) and the dielectric film (capillary) 14 are used. 82 are connected in a mesh pattern.

  Here, the conductor particles 54 are formed of a conductive substance. Therefore, the resistance value of the minute resistor 80 is small. On the other hand, the interval between the conductor particles 54 is as extremely narrow as 10 nm to several hundred nm. Therefore, the capacity of the minute capacitor 82 is large.

  That is, in the capillary film, a large-capacity minute capacitor 82 and a low-resistance minute resistor 80 are connected in a mesh pattern. For this reason, the capacity of the capacitor in which the capillary film is formed as a dielectric layer is increased.

  On the other hand, in the equivalent circuit 74 corresponding to the barium titanate layer, a plurality of capacitors 84 are connected in series to a microcapacitor 82 that forms a capillary film.

  Here, the thickness of the barium titanate layer is several μm. Since the barium titanate layer is thus thick, the capacitance of the capacitor 84 is reduced.

  As shown in FIG. 16, in the capacitor of Comparative Example 2, such a low-capacitance capacitor 84 is connected in series above and below the capillary film (capillary film equivalent circuit 76). For this reason, the capacity of the capacitor of Comparative Example 2 is reduced.

  On the other hand, in the equivalent circuit of the capacitor 40 of the present embodiment, the low-capacitance capacitor 84 derived from the barium titanate layer 68 is connected only below the capillary film (capillary film equivalent circuit 76) (see FIG. 17). ). On the other hand, the microcapacitor 82 forming the equivalent circuit 76 of the capacitor film is directly connected to the upper electrode 20. For this reason, the capacity of the capacitor 40 is increased.

  As described above, the withstand voltage of the capacitor 40 is sufficiently high although only one barium titanate layer 68 is provided between the electrodes 20 and 22. In addition, the capacity of the capacitor 40 is larger than that of a capacitor in which a barium titanate layer is provided between the capillary film 70 and the upper and lower electrodes 20 and 22.

(4) Structure In the above example, the aluminum foil 66 used as the substrate becomes the lower electrode 22.

  However, the structure formed by the barium titanate layer 68 and the capillary film 70 may be peeled off from the aluminum foil 66 by wet etching or the like.

  Such a structure can be used as a member for manufacturing a capacitor. That is, a desired capacitor can be manufactured by forming electrodes on the upper surface and the lower surface of such a structure.

  FIG. 18 is a cross-sectional view illustrating the structure of such a structure 120.

  Such a structure 120 includes a plurality of first conductor particles 54 whose entire surface is covered with a first dielectric film (capillary) 14, and the plurality of first conductor particles 54 is a first dielectric. A first insulating layer 56 separated from each other by a membrane (capillary) 14 is provided. The first insulating layer 56 has an exposed first main surface 62.

  The structure 120 is formed of a dielectric, has a third main surface 63 in contact with the second main surface 60 of the first insulating layer 56, and has an exposed fourth main surface 64. A second insulating layer 58 is provided. Note that the second insulating layer 58 is preferably formed only of a dielectric.

  By forming the upper electrode 20 and the lower electrode 22 on these exposed surfaces, a desired capacitor can be manufactured.

(5) Gas deposition method
FIG. 19 is a diagram illustrating the configuration of the gas deposition apparatus 86 that has been used by the present inventors.

  With reference to FIG. 19, a gas deposition method used for forming a capillary film or the like will be described.

  The gas deposition device 86 includes a film forming chamber 88, an exhaust device 90, a suspended particle generation device 101, and a gas supply device 108. Here, the suspended particle generation apparatus 101 includes a suspended particle generation container 100 and a vibrator 116. The exhaust device 90 includes a booster pump 92 and a vacuum pump 94.

  The gas deposition is performed according to the following procedure using such a gas deposition apparatus 86.

  First, the substrate 96 is fixed to the substrate holder 98.

  Next, the inside of the film forming chamber 88 is exhausted by the exhaust device 90.

  Next, the raw material powder is vacuum degassed for 30 minutes while being heated to about 80 degrees by a vacuum apparatus (not shown). By this pretreatment, moisture adsorbed on the powder surface is removed. Next, the raw material powder 102 subjected to the above pretreatment is filled in the floating particle generating container 100 of the floating particle generating apparatus 101.

  Next, the suspended particle generator 101 is evacuated. Exhaust is performed by opening the first valve 106 provided in the pipe 104 that connects the suspended particle generator 101 and the exhaust device 90.

  At this time, the second valve 110 provided in the pipe 109 that connects the gas supply device 108 to the suspended particle generation device 101 is closed. The third valve 114 provided in the pipe 112 connecting the suspended particle generator 101 to the film forming chamber 88 is also closed. After the exhaust of the suspended particle generator 101 is completed, the first valve 106 is closed.

  Next, vibration is applied to the entire suspended particle generation container 100 by the vibrator 116. The suspended particle generating container 100 to which vibration is applied vibrates and stirs the entire raw material powder 102.

  Next, the second valve 110 is opened while the stirring of the raw material powder 102 is continued, and a compressed gas (for example, He gas) is introduced from the gas supply device 108 to the suspended particle generation container 100. Then, the fine particles forming the raw material powder 102 are mixed with the compressed gas and start to float in the compressed gas. In this way, the raw material powder 102 is made into suspended particles.

  Next, the valve 114 provided in the pipe 112 is opened, and the suspended particles 117 are ejected from the slit-shaped nozzle 118 toward the substrate 96 disposed in the film formation chamber 88.

  The film forming chamber is decompressed by the exhaust device 90. For this reason, the suspended particles 117 are ejected toward the substrate 96 at a speed as high as the speed of sound. The suspended particles 117 ejected from the nozzle 118 collide with the substrate 96 and adhere to the substrate surface.

  As described above, in the gas deposition method, first, the acceleration step of injecting the raw material powder 102 together with the gas is performed. Next, in the gas deposition method, a fixing process is performed in which particles (floating particles 117) included in the injected raw material powder collide with the base (substrate 96) and the particles are fixed to the base.

  For example, in the case of stacking a plurality of deposited films having different structures such as a barium titanate layer and a capillary film, first, while the substrate being deposited is held in the evacuated deposition chamber 88, Replace raw powder. Next, the next deposited film (for example, capillary film) is formed on the deposited film (for example, barium titanate layer) that has already been deposited.

(1) Configuration FIG. 20 is a cross-sectional view for explaining the outline of the capacitor 122 of this embodiment.

  As shown in FIG. 20, in the capacitor 122, a first insulating layer (capillary film) 56 is formed on the lower electrode 22. Further, a second insulating layer (barium titanate layer) 58 is formed on the first insulating layer 56. The upper electrode 20 is formed on the second insulating layer (barium titanate layer) 58.

  The structures of the first insulating layer 56 and the second insulating layer 58 are the same as the structures of the first insulating layer and the second insulating layer described in the first embodiment, respectively.

(2) Manufacturing Method The manufacturing method of the capacitor 122 is substantially the same as the manufacturing method of the capacitor 40 of the first embodiment. However, the manufacturing method of the capacitor main body 122 is that the first insulating layer (capillary film) 56 is formed on the aluminum foil, and then the second insulating layer (barium titanate layer) 58 is formed. The manufacturing method of the capacitor 40 of the first embodiment is different.

  Similarly to the capacitor of the first embodiment, the capacitor 122 of this embodiment also includes a lead electrode provided on the lower electrode 22 and the upper electrode 20 and a case (for example, a ceramic package) that stores the main body of the capacitor. .

(3) Characteristics The characteristics of the capacitor of this example are described in the third row of Table 1 (see FIG. 13). As shown in Table 1, the characteristics of this capacitor are the same as the characteristics of the capacitor of Example 1.

  That is, even if the second insulating layer 58 (barium titanate layer) is formed on the upper electrode side, a capacitor having a high capacity and a high breakdown voltage can be formed.

(1) Configuration FIG. 21 is a cross-sectional view for explaining the outline of the capacitor 124 of this embodiment.

  The configuration of the capacitor 124 is substantially the same as the capacitor 40 of the first embodiment. However, the capacitor 124 includes a third insulating layer 126 (hereinafter referred to as a thin barium titanate layer) inserted into the first insulating layer 125 (capillary film). Here, the third insulating layer 126 is formed of a dielectric (for example, barium titanate) and is thinner than the second insulating layer 58 (barium titanate layer 68).

  As shown in FIG. 21, in this embodiment, two third insulating layers 126 (barium titanate thin layers) are provided.

  Accordingly, in the first insulating layer 125, the first capillary film 128, the first barium titanate thin layer 130, the second capillary film 132, the second barium titanate thin layer 134, and the third The capillary films 136 are sequentially stacked.

  Here, each barium titanate thin layer 130, 134 has a thickness of 0.5 μm. On the other hand, the thickness of each capillary membrane 128, 132, 136 is 10 μm. Therefore, the thickness of the first insulating layer 125 is 44 μm.

  The number of barium titanate thin layers (third insulating layer 126) is not limited to two. For example, the number of barium titanate thin layers (third insulating layer 126) may be one. Alternatively, the number of barium titanate thin layers (third insulating layer 126) may be three or more.

(2) Manufacturing Method The manufacturing method of the capacitor 124 is substantially the same as the manufacturing method of the capacitor 40 of the first embodiment.

  However, in this capacitor manufacturing method, in the step of forming the first insulating film (capillary film) 56, the deposition of the capillary film is interrupted twice, and the third insulating layer 126 (barium titanate thin film) is interrupted in the meantime. Layers 130, 134) are formed by gas deposition. The raw material powder is a powder in which barium titanate particles are aggregated.

  The raw material powder used for forming the thin barium titanate layers 130 and 134 is a powder in which barium titanate particles having a particle diameter of 0.5 μm are aggregated. The raw material powder is preferably formed only of dielectric particles.

(3) Characteristics The characteristics of the capacitor 124 are described in the fourth row of Table 1 (see FIG. 13).

The capacitance density of the capacitor 124 is 280 μm / cm ² which is substantially the same as that of the capacitor 40 of the first embodiment. On the other hand, the withstand voltage of the capacitor 124 is 30V, which is higher than the withstand voltage 20V of the capacitor 40 of the first embodiment.

  That is, when a thin dielectric layer (third insulating layer 126) is inserted into the first insulating layer 125 (capacitor film), the withstand voltage of the capacitor can be improved without substantially reducing the capacitance density.

(4) Structure The capacitor 124 of the present embodiment is also formed using an aluminum foil as a substrate, similarly to the capacitor 40 of the first embodiment.

  Therefore, as in the first embodiment, the first insulating layer 125 and the second insulating layer 58 may be peeled off from the aluminum foil to form a capacitor manufacturing structure.

(1) Configuration FIG. 22 is a cross-sectional view for explaining the outline of the capacitor 138 of the present embodiment.

  The configuration of the capacitor 138 is substantially the same as the capacitor 122 of the second embodiment (see FIG. 20). However, the capacitor 138 includes a third insulating layer (barium titanate thin layer) 126 inserted into the first insulating layer 125 (capillary film). Here, the third insulating layer 126 is formed of a dielectric (for example, barium titanate) and is thinner than the second insulating layer 58 (barium titanate layer 68).

  The configuration of the capacitor 138 is that the second insulating layer 58 is not disposed between the lower electrode 22 and the first insulating layer 125 but between the upper electrode 20 and the first insulating layer 125. Except for this, it is the same as the capacitor 124 of the third embodiment (see FIG. 21).

(2) Manufacturing Method The manufacturing method of the capacitor 138 is substantially the same as the manufacturing method of the capacitor 122 of the second embodiment.

  However, in this capacitor manufacturing method, in the step of forming the first insulating film 125 (capillary film), the deposition of the capillary film is interrupted twice, and the third insulating layer 126 (barium titanate thin film) is interrupted in the meantime. Layers 130, 134) are formed by gas deposition.

  The raw material powder used for forming the thin barium titanate layers 130 and 134 is a powder in which barium titanate particles having a particle diameter of 0.5 μm are aggregated. The raw material powder is preferably formed only of dielectric particles.

(3) Characteristics The characteristics of the capacitor 138 are described in the fifth row of Table 1 (see FIG. 13).

The capacitance density of the capacitor 138 is 280 μm / cm ² which is substantially the same as that of the capacitor 122 of the second embodiment. On the other hand, the withstand voltage of the capacitor 138 is 30 V, which is higher than the withstand voltage 20 V of the capacitor 122 of the second embodiment.

  The characteristics of the capacitor 138 are the same as those of the capacitor 124 of the third embodiment.

  In this embodiment, as in the third embodiment, by inserting a thin dielectric layer into the first insulating layer 125 (capacitor film), it is possible to improve the breakdown voltage without substantially reducing the capacitance density. It shows that it becomes.

(1) Configuration FIG. 23 is a cross-sectional view illustrating the configuration of the capacitor 140 according to this embodiment.

  The capacitor 140 has a plurality of capacitor films 142, 144, and 146. These capacitor films 142, 144, and 146 are laminated, and both sides are fixed by metal foils 148, respectively.

  Further, the plurality of capacitor films 142, 144, 146 are fixed on the substrate 150 with both sides fixed by the metal foil 148. An exterior case 152 is fixed on the substrate 150 so as to cover the capacitor films 142, 144, and 146.

  Here, the metal foil 148 is electrically connected to the side surface of the aluminum foil 154 that forms the substrate of each capacitor film 142, 144, 146. The metal foil 148 is electrically connected to a first terminal 160 provided on the lower surface of the substrate 150 by a wiring 158 provided in a via hole penetrating the substrate 150.

  Further, as will be described later, a carbon film is provided on the upper and lower surfaces of the capacitor films 142, 144, and 146, and a silver paste is applied on the carbon film. Further, a carbon film provided on the lower surface of the lowermost capacitor film 142 is bonded to a pad 162 provided on the upper surface of the substrate 150 by a silver pace.

  Further, the pad 162 is electrically connected to a second terminal 166 provided on the lower surface of the substrate 150 by a wiring 164 provided in a via hole penetrating the substrate 150.

  FIG. 24 is a cross-sectional view illustrating the configuration of the capacitor films 142, 144, 146.

  As shown in FIG. 24, capacitor films 142, 144, and 146 are formed using aluminum foil 154 as a substrate.

  Dielectric layers 42 are formed on both surfaces of the aluminum foil 154 by a gas deposition method. On the dielectric layer 42, a paste-like conductive polymer 168 is applied. Further, paste-like carbon (carbon film 170) and silver pace 172 are sequentially applied thereon. The silver pace 172 is a member that mechanically bonds the upper and lower capacitor films 142, 144, and 146 and at the same time electrically connects them. The silver pace 172 is a member belonging to both the upper and lower capacitor films that are stacked.

  Here, the aluminum foil 154 becomes the lower electrode 176 of the capacitor films 142, 144, 146.

  On the other hand, the conductive polymer 168, the carbon film 170, and the silver pace 172 formed on the dielectric layer 42 form an upper electrode 174, and are connected by a lead wire (not shown) to be electrically integrated. It has become.

  Here, the carbon film 170 of the capacitor film adjacent to the upper and lower sides is electrically connected by the silver paste 172. Therefore, the upper electrodes 174 of the capacitor films 142, 144, and 146 are all electrically connected and integrated.

  Also, the lower electrodes 176 of the capacitor films 142, 144, and 146 are all electrically connected and integrated by the metal foil 148.

  As is clear from the structure described with reference to FIG. 23, the capacitor films 142, 144, and 146 lower electrodes 176 that are electrically integrated are electrically connected to the first terminal 160. Furthermore, the upper electrodes 174 of the capacitor films 142, 144, and 146 that are electrically integrated are electrically connected to the second terminal 166.

  Here, the configuration of the dielectric layer 42 is the same as the configuration of the dielectric layer 42 of Example 1 described with reference to FIG. Therefore, the description of the configuration and manufacturing method of the dielectric layer 42 is omitted.

(2) Characteristics The characteristics of the capacitor 140 are described in the second row of Table 2 (see FIG. 13). The capacity density is converted per dielectric layer.

  As shown in FIG. 23, in this capacitor 140, a plurality of capacitor films 142, 144, 146 are connected in parallel. Here, the capacitor film has a structure in which a dielectric layer is formed on both surfaces of an aluminum foil. Such a structure is similar to an electrolytic capacitor in which an aluminum foil having a dielectric layer formed on both sides is wound. Therefore, such a structure is referred to as an electrolytic capacitor specification.

  The characteristics of the capacitor 140 are the same as the characteristics of the capacitor of Example 1 (see Table 1).

  As described above, the dielectric layer of the capacitor 140 and the dielectric layer of the capacitor of Example 1 have the same configuration. For this reason, the characteristics of both capacitors are the same.

  The configuration of the capacitor of this example is substantially the same as that of the fifth example.

  However, the configuration of the dielectric layer of this capacitor is the same as the configuration of the dielectric layer of Example 2 described with reference to FIG. That is, the barium titanate layer (second insulating layer 58) is provided between the upper electrode 20 and the capacitor film (first insulating layer 56).

  Therefore, the characteristics of this capacitor are the same as the characteristics of the capacitor of Example 2 (see the third row of Table 2).

  The configuration of the capacitor of this example is substantially the same as that of the fifth example.

  However, the configuration of the dielectric layer of this capacitor is the same as the configuration of the dielectric layer of Example 3 described with reference to FIG. That is, the barium titanate layer 68 (second insulating layer 58) is provided between the lower electrode 22 and the capacitor film (first insulating layer 125). Furthermore, a thin barium titanate layer (third insulating layer 126) is inserted into the capacitor film (first insulating layer 125).

  The characteristics of this capacitor are described in the fourth row of Table 2. On the other hand, the characteristics of an electrolytic capacitor using a chemical conversion aluminum oxide film as a dielectric layer are described in the fifth row of Table 3.

As is clear from the comparison of the characteristics of both capacitors, the withstand voltage (30 V) of this capacitor is much higher than the withstand voltage (5 V) of the electrolytic capacitor. The capacitance density of the capacitor (280μF / cm ²⁾ is also higher than the capacity density of the electrolytic capacitor (200μF / cm ^2).

  The characteristics of this capacitor are the same as those of the capacitor of Example 3 having the same configuration of dielectric layers (see the fourth row of Table 1).

  The configuration of the capacitor of this example is substantially the same as that of the fifth example.

  However, the configuration of the dielectric layer of this capacitor is the same as the configuration of the dielectric layer of Example 3 described with reference to FIG. That is, the barium titanate layer 68 (second insulating layer 58) is provided between the upper electrode 20 and the capacitor film (first insulating layer 125). Furthermore, a thin barium titanate layer (third insulating layer 126) is inserted into the capacitor film (first insulating layer 125).

  The characteristics of this capacitor are described in the fifth row of Table 2. On the other hand, the characteristics of an electrolytic capacitor using a chemical conversion aluminum oxide film as a dielectric layer are described in the fifth row of Table 3.

As is clear from the comparison of the characteristics of both capacitors, the withstand voltage (30 V) of this capacitor is much higher than the withstand voltage (5 V) of the electrolytic capacitor. The capacitance density of the capacitor (280μF / cm ²⁾ is also higher than the capacity density of the electrolytic capacitor (200μF / cm ^2).

  The characteristics of this capacitor are the same as the characteristics of the capacitor of Example 5 including the dielectric layers having the same configuration (see the fifth row of Table 1).

(Comparative Example 1)
The configuration of the capacitor of this comparative example is substantially the same as the capacitor of Example 1 described with reference to FIG. However, the dielectric layer of the capacitor does not include the second insulating layer 58 (barium titanate layer 68).

  That is, the dielectric layer of this comparative example is an insulating material formed by a gas deposition method using a mixed powder obtained by adding 5 vol% (volume ratio) of barium titanate particles to aluminum particles subjected to surface oxidation treatment. It is formed only by a layer (capillary membrane).

  The characteristics of this capacitor are described in the second row of Table 3.

  As shown in Table 3, the withstand voltage of this capacitor is 3V. This withstand voltage is remarkably lower than the withstand voltage of the capacitors of the above embodiments having the second insulating layer 58 (barium titanate layer 68).

(Comparative Example 2)
The configuration of the capacitor of this comparative example is substantially the same as the capacitor of Example 1 described with reference to FIG. However, the dielectric layer of the capacitor is composed of barium titanate between the first insulating layer 125 (capillary film) and the upper electrode 20 and between the first insulating layer 56 (capillary film) and the lower electrode 22. A layer 68 is formed.

  The characteristics of this capacitor are described in the third row of Table 3.

As shown in Table 3, the capacitance density of this capacitor is 200 μF / cm ² . This breakdown voltage is lower than the capacitance density of the capacitor of each of the above embodiments having only one barium titanate layer (second insulating layer 58).

(Modification)
In the above example, the dielectric layer is formed on the aluminum foil. However, a capacitor may be formed by depositing a dielectric layer by a gas deposition method on a printed board to which a copper foil is attached or inside a resin build-up board.

In the above example, no special treatment is applied to the dielectric layer after film formation. However, laser irradiation (for example, irradiation with a CO ₂ laser or YVO 4 laser with an output of 10 W) may be applied to the dielectric layer after film formation. When such laser irradiation is performed, the dielectric layer becomes dense and the capacity is further improved.

  Further, the formed dielectric layer may be subjected to a chemical conversion treatment for 15 minutes by applying a DC voltage in an aqueous solution of ammonium adipate. In this way, a chemical film is formed on the entire surface of the dielectric layer, so that the breakdown voltage is further improved. The voltage and processing time used for the chemical conversion treatment are, for example, 15 V and 15 minutes.

  In each of the above embodiments, the upper electrode or the lower electrode is formed directly on the surface of the capillary membrane. However, the upper electrode or the lower electrode may be formed after the surface of the capillary film is polished. This increases the capacitance of the capacitor.

  Moreover, in the above example, the electroconductive particle contained in raw material powder is an aluminum particle. However, the conductive particles may be particles of valve metal such as titanium, tantalum, zirconium, silicon, and magnesium. Further, the conductive particles contained in the raw material powder may be particles made of an alloy containing these valve metals as components.

  Further, as the dielectric covering these conductor particles, various dielectrics such as tantalum oxide, titanium oxide, zirconium oxide, hafnium oxide, silicon dioxide, silicon nitride, aluminum nitride, tantalum nitride, and magnesium oxide may be used. Good. In addition to dielectric layers based on valve metals, various perovskite structure oxides and bismuth layered structures such as barium titanate, strontium titanate and other titanate complex oxides, zirconate oxides, or solid solutions thereof. A film of a high dielectric constant material such as an oxide or a tungsten bronze structure oxide may be used. When the surface of the conductor particles is covered with a natural oxide film, the conductor particles are covered with a two-layered dielectric film formed by the natural oxide film and these dielectrics.

  In addition, as dielectric particles that are mixed with conductive particles covered with a dielectric material to form a raw material powder, various dielectric materials such as zirconium oxide, hafnium oxide, silicon dioxide, silicon nitride, aluminum nitride, tantalum nitride, and magnesium oxide can be used. The body may be used. In addition to dielectric layers based on valve metals, various perovskite structure oxides and bismuth layered structures such as barium titanate, strontium titanate and other titanate complex oxides, zirconate oxides, or solid solutions thereof. A film of a high dielectric constant material such as an oxide or a tungsten bronze structure oxide may be used.

  These coatings are made by mixing sol-gel liquids and alkoxide liquids of various oxides, and coating the liquid surface with the atomizing method such as spraying or supplying gas from below to cause convection. A method of coating using a liquid that is dried and then heat-treated and solidified to form, or a vapor phase method such as sputtering or laser ablation can be used.

  In addition, it is preferable that the dielectric constant of these dielectric particles is higher than the dielectric constant of the oxide of the conductor particles. For example, the dielectric particles are preferably formed of a dielectric having a relative dielectric constant of 8 or more.

  The average particle size of the dielectric particles is preferably smaller than the average particle size of the conductor particles. For example, the average particle diameter of the dielectric particles is preferably 1 μm or less.

  In addition, regarding the barium titanate layer formed on either or both of the upper and lower layers of the capillary film, not only barium titanate but also titanate-based complex oxides such as barium titanate and strontium titanate, zirconate oxide or Films of high dielectric constant materials such as various perovskite structure oxides, bismuth layered structure oxides, tungsten bronze structure oxides such as solid solutions thereof may be used.

  In addition, the film formation method above and below the capillary film is not limited to gas deposition, but a method of forming an insulating film such as sputtering, laser ablation, vapor deposition, screen printing, sol-gel liquid coating, alkoxide liquid coating, or thermal spraying is applied. can do.

  As for the structure, it is possible to form the same structure as a ceramic multilayer capacitor in which a dielectric film (capillary layer + dielectric layer) / metal film is alternately formed on a substrate. The metal film to be formed is formed by sputtering, vapor deposition, screen printing, gas deposition, or the like.

2 ... Particles 4 ... Conductor particles 6 ... Dielectric 8 ... Al particles 10 ... Aluminum oxide 12 ... Barium titanate particles 14 ... Dielectric film (capillary) 16 ... Dielectric layer 18 (capacitor) 20 capacitor 20 upper electrode 22 lower electrode 24 aluminum oxide film 26 barium titanate continuous film 28 leak current 30 -Withstand voltage 32 ... current path 34 ... insulating layer 36 ... deposited film (capillary film)
38 ... (considered by the present inventor) Capacitor 40 ... Capacitor 42 of Example 1 ... Dielectric layer 44 ... Capacitor body 46 of Example 1 ... First lead electrode 48 ..Second lead electrode 50 ... Case 54 ... Conductive particles 56 ... First insulating layer 58 ... Second insulating layer 60,62 ... Main surface of the first insulating layer 63, 64 ... main surface of second insulating layer 66 ... aluminum foil 68 ... barium titanate layer 70 ... capillary film 74, 78 ... equivalent circuit 76 corresponding to barium titanate layer ... Equivalent circuit 80 corresponding to capillary membrane ... Small resistor 82 ... Small capacitor 84 ... Capacitor 86 (forming an equivalent circuit of a barium titanate layer) ... Gas deposition apparatus 88 ..・ Deposition chamber 90 ... Exhaust device 92 ... Booster pump 94 ... Vacuum pump 96 ... Substrate 98 ... Substrate holder 100 ... Floating particle generator 101 ... Floating particle generator 102 ... Raw material powder 104 ... Pipe 106 ... 1st valve 108 ... gas supply device 109 ... piping 110 ... 2nd valve 112 ... piping 114 ... 3rd valve 116 ... vibrator 117 ... suspended particle 118 ... Nozzle 120 ... Structure 122 ... Capacitor 124 of the second embodiment ... Capacitor 125 of the third embodiment ... First insulating layer 126 ... Third insulating layer 128 First capillary film 130 ... first barium titanate thin layer 132 ... second capillary film 134 ... second barium titanate thin layer 136 ... third capillary film 138 ... Capacitor 140 of Example 4 ... Capacitors 142, 144, 146 of Example 5 ... Capacitor film 148 ... Metal foil 150 ... Substrate 152 ... Exterior case 154 ... Aluminum foil 158 ... -Wiring 160 ... 1st terminal 162 ... Pad 164 ... Wiring 166 ... 2nd terminal 168 ... Conductive polymer 170 ... Carbon 172 ... Silver paste 174 ... . Upper electrode 176 ... lower electrode

Claims (7)

A first insulating layer including a plurality of first conductive particles whose entire surface is covered with a first dielectric film, wherein the plurality of first conductive particles are separated from each other by the first dielectric film; ,
A first electrode in contact with a first main surface of the first insulating layer;
A second insulating layer formed of a dielectric and in contact with a second main surface of the first insulating layer;
A second electrode in contact with the second insulating layer ;
A capacitor comprising a third insulating layer formed of a dielectric and inserted into the first insulating layer . The capacitor of claim 1,
The third insulating layer is thinner than the second insulating layer.
Features a capacitor. A plurality of first conductor particles whose entire surface is covered with a first dielectric film, wherein the plurality of first conductor particles are isolated from each other by the first dielectric film and exposed; A first insulating layer having a main surface;
A second insulating layer formed of a dielectric material, having a third main surface in contact with the second main surface of the first insulating layer, and having an exposed fourth main surface;
A structure including a third insulating layer formed of a dielectric and inserted into the first insulating layer . The structure according to claim 3,
The structure according to claim 3, wherein the third insulating layer is thinner than the second insulating layer . A first insulating layer including a plurality of first conductive particles whose entire surface is covered with a first dielectric film, wherein the plurality of first conductive particles are separated from each other by the first dielectric film; ,
A first electrode in contact with a first main surface of the first insulating layer;
A second insulating layer formed of a dielectric and in contact with a second main surface of the first insulating layer;
A second electrode in contact with the second insulating layer ;
A method of manufacturing a capacitor comprising a third insulating layer formed of a dielectric and inserted into the first insulating layer ,
The surface was covered with a second dielectric film using a film forming method comprising an acceleration step of injecting raw material powder together with gas and a fixing step of causing particles contained in the injected raw material powder to collide with a base. The first insulating layer is formed by the raw material powder having the second conductor particles as the particles,
Using the film forming method, the second insulating layer is formed by the raw material powder having the first dielectric particles as the particles ,
Using the film forming method, the third insulating layer is formed from the raw material powder using the second dielectric particles as the particles.
Method of manufacturing a key Yapashita. The capacitor according to claim 5, wherein
The method of manufacturing a capacitor, wherein the third insulating layer is thinner than the second insulating layer . In the manufacturing method of the capacitor according to claim 5,
The raw material powder used for forming the first insulating layer contains third dielectric particles;
A feature of the capacitor manufacturing method.

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