JP5769532B2 - Capacitor and manufacturing method thereof - Google Patents

Description

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

  Generally, a capacitor is provided on both end surfaces of a laminate in which a plurality of dielectric layers are laminated, an internal electrode provided between the dielectric layers of the laminate, and an internal electrode. External electrodes (see Patent Document 1).

  Here, a gap opening at the end face has been formed between the internal electrode and the dielectric layer. In addition, when plating the surface of the external electrode, the plating solution passes through the external electrode and enters the laminate along the interface between the internal electrode and the dielectric layer through the gap, eroding the dielectric layer and the internal electrode. And may cause structural defects. Therefore, a water repellent treatment agent such as a silane coupling agent has been provided in this gap in order to prevent the plating solution from entering the laminate.

WO2007 / 119281 Publication

  However, when a capacitor as shown in Patent Document 1 is subjected to a heat treatment such as baking of an external electrode at the time of manufacture, the water repellent treatment agent such as a silane coupling agent is easily burned off by heat. Therefore, as described above, there is a problem in that the plating solution easily enters the laminated body through the gap between the internal electrode and the dielectric layer through the external electrode, thereby causing structural defects.

The capacitor of the present invention includes a plurality of laminated dielectric layers and a plurality of internal electrodes formed along an interface between the dielectric layers, and each end of the internal electrode is exposed to a predetermined end surface. A laminated body and an external electrode provided on the predetermined end face so as to connect the internal electrodes exposed on the predetermined end face to each other, and a predetermined gap is provided between the internal electrode and the dielectric layer. A gap opening is provided in the end face, and a glass obtained by curing a glass precursor mainly composed of organopolysiloxane is provided in the gap.

The capacitor manufacturing method of the present invention includes a plurality of laminated dielectric layers and a plurality of internal electrodes formed along an interface between the dielectric layers, and each end of the internal electrodes is formed on a predetermined end surface. A method for manufacturing a capacitor, comprising: preparing an exposed laminated body; and providing an external electrode on a predetermined end face so as to connect the internal electrodes exposed on the predetermined end face to each other. the said internal electrodes disposed between the dielectric layer, a gap which is open to a predetermined said end face, the step of providing a glass and Nde including the step of providing the glass was the main component an organopolysiloxane The glass precursor is injected into the gap and cured .

  According to the capacitor of the present invention, an opening is provided in the end face between the internal electrode and the dielectric layer, and the external electrode is annealed because glass is provided in the gap. The glass in the gap between the internal electrode and the dielectric layer remains without being burned off by heat, so that the plating solution can penetrate into the laminate during the plating process of the external electrode surface. It can be suppressed with this glass. Therefore, erosion of the dielectric layer and the internal electrode can be suppressed and structural defects can be prevented.

  According to the method for manufacturing a capacitor of the present invention, the method includes the step of providing glass in a gap that is provided between the internal electrode and the dielectric layer and opens to the predetermined end face. Even if heat treatment such as annealing or annealing is performed, glass remains in the gap between the internal electrode and the dielectric layer. Infiltration can be suppressed with this glass. Therefore, erosion of the dielectric layer and the internal electrode can be suppressed and structural defects can be prevented.

It is an expanded sectional view near the exposure end face of an internal electrode in the layered product of a capacitor by an example of an embodiment of the invention. It is sectional drawing of the capacitor | condenser by an example of embodiment of this invention. It is explanatory drawing of the manufacturing method of the capacitor | condenser by an example of embodiment of this invention. It is explanatory drawing of the manufacturing method of the capacitor | condenser by the other example of embodiment of this invention. It is an expanded sectional view near the exposed end face of an internal electrode in a multilayer body of a capacitor according to another example of an embodiment of the invention.

  Hereinafter, an example of an embodiment of a capacitor of the present invention will be described in detail with reference to the drawings. A capacitor 1 shown in FIG. 2 includes a multilayer body 2, an internal electrode 3, and an external electrode 4 as a basic configuration.

  The stacked body 2 includes a plurality of stacked dielectric layers 5 and a plurality of internal electrodes 3 formed along an interface between the dielectric layers 5. As shown in FIG. 2, the laminate 2 includes a first main surface 2a (upper surface) and a second main surface (lower surface) 2b facing each other, a first side surface (not shown) and a first main surface facing each other. It is formed in a substantially rectangular parallelepiped shape having two side surfaces (not shown) and a first end surface 2e and a second end surface 2f facing each other. Moreover, the dimension of the laminated body 2 makes the length of the long side of the laminated body 2 into 0.4-3.2 mm, for example, and makes the length of the short side of the laminated body 2 into 0.2-1.6 mm, for example.

The dielectric layer 5 has a rectangular shape, and the thickness per layer is, for example, 1 to 2 μm. For example, 20 to 2000 layers of the dielectric layer 5 are stacked in the stacked body 2. Examples of the material for the dielectric layer 5 include BaTiO ₃ , CaTiO ₃ , SrTiO _{3, and} CaZrO ₃ . As another _example, BaTiO _3, CaTiO 3, and SrTiO ₃ or CaZrO ₃ as a main component, Mn compound, Fe compound, Cr compounds, Co compounds, or may be Ni compound or the like is added .

  As shown in FIG. 2, the internal electrodes 3 a and 3 b are provided so that each end is exposed to one of the end faces 2 e and 2 f of the multilayer body 2. The internal electrodes 3 a exposed on the first end face 2 e and the internal electrodes 3 b exposed on the second end face 2 f are alternately arranged so as to face each other with the dielectric layer 5 interposed therebetween. Thereby, an electrostatic capacity can be obtained.

  The internal electrode 3 is formed between 20 and 2000 layers between the dielectric layers 5 of the laminate 2. Examples of the material of the internal electrode 3 include metals such as Ni, Cu, Ag, Pd, and Au, or alloys such as an Ag—Pd alloy containing one or more of these metals. All the internal electrodes 3 are preferably formed of the same metal or alloy.

The overall dimensions of the internal electrode 3 are, for example, 0.39 to 3.1 mm in the long side direction of the multilayer body 2 and are, for example, 0.19 to 1.5 mm in the short side direction of the multilayer body 2. Although the thickness of the internal electrode 3 is not specifically limited, For example, it is about 0.3-2 micrometers.

  The external electrodes 4a and 4b are provided on the predetermined end surfaces 2e and 2f, respectively, so as to connect the internal electrodes 3a and 3b exposed on any one of the end surfaces 2e and 2f. In the example shown in FIG. 2, the external electrodes 4 a and 4 b are respectively provided at the end portions of the stacked body 2. The external electrodes 4a and 4b are formed with a thickness of 5 to 50 μm. The material of the external electrode 4 may be a metal material such as silver, nickel, palladium, or an alloy thereof other than copper.

  On the surface of the external electrodes 4a and 4b, one or a plurality of plating films such as a Ni plating film and a Sn plating film are formed in order to protect the external electrodes 4a and 4b and improve mountability. It is preferable. For example, a laminate of a Ni plating film and a Sn plating film may be formed on the surfaces of the external electrodes 4a and 4b.

  The method for bonding the external electrodes 4a and 4b to the wiring board is not particularly limited. For example, an appropriate joining member such as high-temperature solder such as Sn-Sb-based high-temperature solder, Sb-Pb eutectic solder, Sn-Ag-Cu-based Pb-free solder, Sn-Cu-based Pb-free solder, or resin containing conductive fine particles The external electrodes 4a and 4b and the wiring board can be bonded using

  Further, as in the example shown in FIG. 1, a gap 6 that opens to the end face 2 e (2 f) is often provided between the internal electrode 3 and the dielectric layer 5. In the example shown in FIG. 1, a glass 7 is provided in the gap 6. With this configuration, it is possible to suppress the plating solution used when forming the plating film on the surface of the external electrode 4 from entering the laminated body 2 through the gap 6 through the external electrode 4. Further, the glass 7 does not evaporate even during high temperature processing such as annealing of the external electrode. Therefore, since the glass 7 remains in the gap 6, even if a high-temperature treatment is required in the manufacturing process, it is possible to suppress the infiltration of the plating solution into the laminate 2 and to provide a capacitor in which the characteristics are not easily changed. .

As the glass 7, for example, a material mainly composed of silica is used. The glass 7 can be set to a heat resistant temperature of about 700 to 1700 ° C. Further, since the baking temperature of the external electrode 4 is about 800 ° C. and the annealing temperature is about 600 ° C., the heat resistance temperature higher than these temperatures may be set as necessary. Moreover, it is preferable that the glass 7 has alkali resistance or acid resistance. Thereby, even if a plating solution touches, it does not melt | dissolve, Therefore The penetration | invasion of the plating solution to a laminated body can be prevented effectively.

  The capacitor 1 having the above configuration is manufactured by a ceramic green sheet lamination method as described below.

  First, a plurality of green sheets to be the dielectric layer 5 are prepared. In this step, the ceramic green sheet is obtained by preparing a slurry-like ceramic slurry by adding and mixing a suitable organic solvent or the like to the ceramic raw material powder and the organic binder, and molding the slurry by a doctor blade method or the like. .

  Next, the internal electrode 3 is formed on the green sheet. In this step, a conductive material to be a pattern of the internal electrode 3 is formed on the obtained ceramic green sheet by screen printing or the like. In addition, the pattern of the several internal electrode 3 is printed on this one green sheet so that many capacitors can be obtained from one green sheet.

  Next, after laminating and pressing a plurality of ceramic green sheets, a raw laminated body in which many pieces are integrated is produced. This laminated body is cut to obtain a raw body of the capacitor 1 as a single laminated body.

Next, the capacitor body 1 in a raw state is fired to obtain a laminate 2. In this step, for example, by firing at 800 to 1050 ° C., the laminate 2 is obtained as shown in FIG.
By this step, the green sheet becomes the dielectric layer 5 and the conductor material becomes the internal electrode 3.

  Next, as shown in FIG. 3B, a glass 7 is provided in a gap 6 provided between the internal electrode 3 and the dielectric layer 5 and opening in a predetermined end surface 2 e (2 f). This step is performed, for example, by applying a glass frit melted at a high temperature of about 300 to 400 ° C. to the end face of the laminated body, injecting it into the gap 6 and then cooling and hardening. Moreover, it is preferable to perform the process of providing the glass 7 by inject | pouring the glass precursor which made organopolysiloxane the main ingredient into the clearance gap 6, and hardening it. This glass precursor is liquid at room temperature, and when left at room temperature, it naturally cures to become glass 7. Therefore, the process of providing the glass 7 in the gap 6 can be performed at room temperature without increasing the temperature. As a result, the glass 7 can be provided in the gap 6 without causing cracks due to the influence of high heat in the laminate 2.

Specifically, a method is adopted in which the laminate 2 is dipped in a liquid glass precursor and injected into the gap 6 by reducing the pressure, and then the laminate 2 is pulled up and dried at room temperature. In order to accelerate drying, the laminate 2 pulled up from the glass precursor is heated at 60 ° C. for 1 hour, and then 120
A method of drying at 1 ° C. for 1 hour can also be employed. Alternatively, a method may be employed in which the glass 7 is provided by spraying a liquid glass precursor on the end face of the laminate 2 where the internal electrode 3 is exposed, injecting the liquid glass precursor into the gap 6 and drying the glass 7.

  This liquid glass precursor consists of a main ingredient, a crosslinking agent, and a curing catalyst. The main material is composed of a liquid organopolysiloxane having a methyl group or a phenyl group. The cross-linking material is composed of an organopolysiloxane having a functional side chain such as an alkoxy group, an acyloxy group, or an oxime group. The curing catalyst can be a metal-containing organic compound such as Zn, Al, Co, or Sn, or an inorganic substance such as boron ion or halogen. These three components are mixed to form a one-pack type silica solution, which is preferably used without a solvent, but may be diluted with a solvent such as isopropyl alcohol.

  In addition, a liquid glass precursor will harden | cure naturally when left still at normal temperature. In the curing mechanism, as a first step, first, the functional group (methyl group or phenyl group) of the organopolysiloxane, which is the main material, is hydrolyzed by moisture in the air and changed to a hydroxyl group (OH). Next, as a second step, the functional group of the organopolysiloxane that is a crosslinking agent acts on the hydroxyl group of the organopolysiloxane, and further receives the action of a curing catalyst to cause a dealcoholization reaction, and this reaction gradually proceeds. Thus, a high-molecular polysiloxane compound having a three-dimensional structure is formed.

  Next, as shown in FIG. 3C, a conductive paste prepared by mixing metal particles such as Ag particles and Pd particles, glass frit, and an organic vehicle is applied to both ends of the laminate 2 and baked. Thus, the external electrode 4 is formed. The external electrode 4 may be formed by a thin film forming method such as vapor deposition, plating, or sputtering.

  Next, on the surface of the obtained external electrode 4, a nickel (Ni) plating layer, a copper (Cu) plating layer, a gold (Au) plating layer, a tin (Sn) plating layer, a solder plating layer, etc. A capacitor 1 is obtained by performing a plating process for forming a plating layer.

  According to such a manufacturing method, when the external electrode 4 is formed by baking, the glass 7 does not evaporate. Therefore, the glass 7 remains in the gap 6 even after baking, and the plating solution is formed during plating formation on the surface of the external electrode 4. Can be suppressed by the glass 7.

Further, the glass 7 is provided in the gap 6 before forming the external electrode 4, but the glass 7 may be provided in the gap 6 after forming the external electrode 4 as shown in FIG. 4. Even in this case, for example, when the annealing process is performed on the external electrode 4, the glass 7 does not evaporate by heat, and thus the same effect as described above can be obtained.

  In order to provide the glass 7 in the gap 6 after the formation of the external electrode 4, the capacitor 1 in which the external electrode 4 is formed is immersed in a liquid glass precursor and injected into the gap 6 by reducing the pressure. Then, it may be dried as described above.

  Also in this manufacturing method, the external electrode 4 may be formed by a plating method. Even in this case, for example, when the annealing process is performed on the external electrode 4, the glass 7 does not evaporate by heat, and thus the same effect can be obtained.

  When the external electrode 4 is formed by a plating method, it is preferable to provide the glass 7 in the gap 6 before forming the external electrode 4. By doing so, the glass 7 can prevent the plating solution for forming the external electrode 4 from entering the laminated body 2.

  The present invention is not limited to the embodiments described above, and various changes and improvements can be made without departing from the scope of the present invention.

  For example, the rounded portion may be formed by chamfering the laminate 2 by barrel polishing or the like. By this step, it is possible to prevent microcracks from being removed and chipped in the rounded portion of the obtained laminate 2. Furthermore, the barrel polishing has an effect of removing the surface oxide film of the metal particles and exposing the metal surface to improve the plating adhesion.

  In addition, after the step of providing the glass 7 in the gap 6 for the laminate 2 before forming the external electrode 4, the glass 7 attached to the exposed end surface of the internal electrode 3 in the laminate 2 is sandblasted or barrel-polished. It is preferable to remove by, for example. Thereby, the electrical conduction of the internal electrode 3 to the external electrode 4 can be improved.

  Further, for example, as shown in FIG. 5, it is preferable to provide glass 7 also in the holes 8 generated in the external electrode 4 by the baking process. In this case, when the surface of the external electrode 4 is plated, the plating solution penetrates through the holes 8 and enters the laminated body. Can be hindered. Therefore, the effect of preventing the plating solution from entering the laminated body can be further enhanced.

In order to obtain such a configuration, the glass 7 may be provided in the void 8 inside the external electrode 4 after the glass 7 is provided in the gap 6 and the external electrode 4 is formed. Further, when the glass 7 is provided in the gap 6 after forming the external electrode 4, it is preferable because the glass 7 can be provided in the gap 6 and the holes 8 at the same time.
The holes 8 inside the external electrode 4 are likely to occur when the external electrode 4 is formed by baking.

  In addition, after forming the external electrode 4 and performing the step of providing the glass 7 in the gap 6, it is preferable to remove the glass adhering to the surface of the external electrode 4 by sandblasting, barrel polishing, or the like. Thereby, the wettability with respect to the surface of the external electrode 4 of a plating film can be made favorable. Moreover, while the glass precursor adhering to the surface of the external electrode 4 is in a liquid state before curing, the glass precursor is blown off with air or the like to suppress the formation of glass on the surface of the external electrode 4. May be.

1: Capacitor 2: Laminate 3 (3a, 3b): Internal electrode 4 (4a, 4b): External electrode 5: Dielectric layer 6: Gap 7: Glass 8: Hole

Claims (4)

A laminated body including a plurality of laminated dielectric layers and a plurality of internal electrodes formed along an interface between the dielectric layers, each end of the internal electrodes being exposed to a predetermined end face;
An external electrode provided on the predetermined end face so as to connect the internal electrodes exposed on the predetermined end face to each other;
A gap opening at a predetermined end face is provided between the internal electrode and the dielectric layer, and a glass obtained by curing a glass precursor mainly composed of organopolysiloxane is provided in the gap. Capacitor characterized by that.   The capacitor according to claim 1, wherein the external electrode has a hole therein, and the glass is provided in the hole. A laminated body including a plurality of laminated dielectric layers and a plurality of internal electrodes formed along an interface between the dielectric layers, each end portion of the internal electrodes being exposed to a predetermined end face is prepared. Process,
Forming an external electrode on the predetermined end face so as to connect the internal electrodes exposed on the predetermined end face to each other,
Wherein provided between the internal electrode and the dielectric layer, a gap which is open to a predetermined said end face, and Nde including the step of providing a glass,
The step of providing the glass is performed by injecting a glass precursor containing organopolysiloxane as a main ingredient into the gap and curing the glass precursor . The method for manufacturing a capacitor according to claim 3, further comprising a step of providing glass in the holes inside the external electrode.

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