JP5773726B2 - Multilayer ceramic capacitor - Google Patents

Description

  The present invention relates to a multilayer ceramic capacitor having enhanced bonding strength with an external electrode.

  Multilayer ceramic capacitors are widely used as electronic components for surface mounting. The structure is such that an extraction portion of the internal electrode layer is provided on the end face of the capacitor body which is formed by alternately laminating a plurality of dielectric layers mainly composed of ceramics and the internal electrode layer, and covers the surface. An external electrode for connecting to an external circuit is formed.

  An external electrode constituting such a multilayer ceramic capacitor is generally made of a conductive paste composed of metal powder (silver, palladium, nickel, copper, etc.), glass powder, and an organic vehicle (a solution in which a binder is dissolved in an organic solvent). It is applied to the end face of the capacitor body and formed by firing in air or nitrogen, and then a plating film such as a Ni plating film and a Sn-containing plating film is formed on the surface of the external electrode ( For example, see Patent Document 1).

  In recent years, with the development of mobile computing devices such as mobile phones, multilayer ceramic capacitors are increasingly required to be smaller and have higher capacities. In order to increase the volume of the capacitor main body that contributes to the development of capacitance for the purpose of obtaining capacitance, it has been attempted to form a thinner external electrode (see, for example, Patent Document 2). .

JP-A-5-3132 Japanese Patent Laid-Open No. 2001-210545

  However, since the area ratio of the dielectric layer occupying the end face of the capacitor body is reduced due to the thinning of the dielectric layer in recent years, the multilayer ceramic capacitor is made of glass in the external electrode and the dielectric layer of the capacitor body. Since there are few contact points at the interface, there is a problem that the bonding strength between the external electrode and the capacitor body is low.

  Accordingly, an object of the present invention is to provide a multilayer ceramic capacitor having high bonding strength between the capacitor body and the external electrode.

The multilayer ceramic capacitor of the present invention is provided on a capacitor body in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately stacked, and on an end surface of the capacitor body where the internal electrode layer is exposed, and the internal electrode layer A multilayer ceramic capacitor having an external electrode connected to the capacitor body, and the capacitor body is formed of Si between the dielectric layer on the end surface and the external electrode when the multilayer ceramic capacitor is viewed in a longitudinal section. have a oxide layer, the internal electrode layer, and has a ridge protruding from said end face of said capacitor body, characterized in that it enters the part of the oxide layer of the Si to the projecting portion .

In the multilayer ceramic capacitor, it is preferable that the protrusion is an alloy of a metal of the internal electrode layer and a metal of the external electrode.

  According to the present invention, the bonding strength between the capacitor body and the external electrode can be increased.

It is a schematic longitudinal cross-sectional view which shows embodiment of the multilayer ceramic capacitor of this invention. FIG. 10 is a schematic cross-sectional view showing another embodiment of the multilayer ceramic capacitor and enlarging the vicinity of the interface between the capacitor body and the external electrode.

  FIG. 1 is a schematic longitudinal sectional view showing an embodiment of the multilayer ceramic capacitor of the present invention. In the multilayer ceramic capacitor of this embodiment, external electrodes 3 are formed at both ends of the capacitor body 1. The external electrode 3 is formed by baking, for example, Cu or an alloy paste of Cu and Ni, and a plating film for improving the solder joint is formed on the surface of the external electrode 3 (FIG. 2). The plating film is not shown.)

  The capacitor body 1 has a substantially rectangular parallelepiped shape, and is configured by alternately laminating dielectric layers 5 and internal electrode layers 7 made of dielectric ceramics. An internal electrode layer 7 is exposed at an end face 1 a in a direction perpendicular to the stacking direction of the capacitor body 1, and the internal electrode layer 7 and the external electrode 3 are joined. In FIG. 1, the lamination state of the dielectric layer 5 and the internal electrode layer 7 is shown in a simplified manner, but the dielectric layer 5 and the internal electrode layer 7 are a laminate of several hundred layers. The number of laminated layers is preferably 100 layers or more, particularly 200 layers or more in that the capacity of the multilayer ceramic capacitor can be increased.

  The dielectric layer 5 can use a dielectric ceramic mainly composed of barium titanate. For example, crystal particles in which barium titanate contains magnesium oxide, a rare earth element (RE) oxide, manganese oxide, or the like as a solid solution. And a dielectric ceramic composed of a grain boundary phase mainly composed of silicon oxide. The types of dielectric porcelain are not limited to those described above, but other dielectrics such as barium titanate in which elements such as calcium and strontium are dissolved or those dielectric materials are combined. Porcelain can also be used. The average thickness of the dielectric layer 5 is preferably 2 μm or less, and particularly preferably 1 μm or less. As a result, the multilayer ceramic capacitor can be reduced in size and capacity. In addition, when the average thickness of the dielectric layer 5 is 0.4 μm or more, it is possible to reduce the variation in capacitance and stabilize the capacitance-temperature characteristic.

  As a material for forming the internal electrode layer 7, a base metal such as nickel (Ni) or copper (Cu) is desirable because the manufacturing cost can be suppressed even when the number of layers is increased, and simultaneous firing with the dielectric layer 5 can be performed. In particular, nickel (Ni) is more desirable. Further, the thickness of the internal electrode layer 7 is preferably 0.5 μm or more because it can be firmly bonded to the external electrode 3. On the other hand, when the multilayer ceramic capacitor is downsized, the number of layers can be increased. It is desirable that it is 2 μm or less for the reason.

The external electrode 3 constituting the multilayer ceramic capacitor of the present embodiment is made of a sintered body of a metal and a glass phase mainly composed of SiO ₂ , for example, copper (Cu) powder or Cu and another metal. An alloy powder with a component (for example, a transition metal such as Ni) and a glass powder are sintered.

  Furthermore, the multilayer ceramic capacitor of this embodiment has a Si oxide layer 8 between the dielectric layer 5 on the end face 1a of the capacitor body 1 and the external electrode 3 when the multilayer ceramic capacitor is viewed in a longitudinal section. Features. According to the present invention, since the Si oxide layer 8 is adhered to the dielectric layer 5 alternately laminated with the internal electrode layer 7, the gap between the external electrode 3 and the dielectric layer 5 of the capacitor body 1 is Bonding strength can be increased. This is because the glass component is unevenly distributed at the interface between the external electrode 3 and the dielectric layer 5 on the end face 1a of the capacitor body 1, so that even if the area ratio of the dielectric layer 5 in the capacitor body 1 is small, the external electrode This is because the number of contact points at the interface between the end face 1a of the capacitor body 1 and the dielectric layer 5 increases. For this reason, the electrical connection between the internal electrode layer 7 and the external electrode 3 is strengthened, and a capacitance close to the design value can be obtained.

  Further, since the Si oxide layer 8 is formed on the end face 1a of the capacitor body 1, the volume of the gap between the end face 1a of the capacitor body 1 and the external electrode 3 can be reduced. For this reason, infiltration of moisture and plating solution from the surface side of the external electrode 3 is suppressed, and it is possible to improve moisture resistance.

  Here, the Si oxide layer 8 is a layer of Si on the end surface 1a of the capacitor body 1 when a cross section near the boundary between the capacitor body 1 and the external electrode 3 is analyzed using an X-ray microanalyzer. It is a state in which oxygen is detected as a light element in association with Si. The Si oxide layer 8 may contain a small amount of components contained in the external electrode 3, the internal electrode layer 7, and the dielectric layer 5.

  In the multilayer ceramic capacitor of this embodiment, the internal electrode layer 7 desirably has a protruding portion 9 protruding from the end surface 1 a of the capacitor body 1. Thereby, the joining strength between the metals of the external electrode 3 and the internal electrode layer 7 can be further increased, the electrostatic capacity can be made closer to the design value, and the thermal shock resistance can be increased.

  In the multilayer ceramic capacitor of this embodiment, it is desirable that the protruding portion 9 is an alloy of the metal of the internal electrode layer 7 and the metal of the external electrode 3. When the protruding portion 9 is formed of an alloy of the metal of the internal electrode layer 7 and the metal of the external electrode 3, the electrical connection between the metal of the internal electrode layer 7 and the external electrode 3 becomes strong. The capacitance of the multilayer ceramic capacitor can be made closer to the design value.

  Here, the alloy means that when the metal constituting the internal electrode layer 7 is, for example, nickel (Ni) and the metal constituting the external electrode 3 is, for example, copper (Cu), Ni and Cu Although it becomes an alloy, a part of the protrusions 9 may not be alloyed, and at least one metal of Ni simple substance and Cu simple substance may be mixed. The thickness of the protruding portion 8 (the thickness in the same direction as the lamination direction of the internal electrode layer 7) is preferably equal to the thickness of the internal electrode layer 7.

  In the present embodiment, the region of the alloy forming the protruding portion 9 may extend to a part of the internal electrode layer 7 formed inside the capacitor body 1, thereby the protruding portion. 9 and the internal electrode layer 7 can be further strengthened.

FIG. 2 shows another embodiment of the multilayer ceramic capacitor, and is an enlarged schematic cross-sectional view of the vicinity of the interface between the capacitor body and the external electrode. In the multilayer ceramic capacitor of this embodiment, it is desirable that a part of the Si oxide layer 8 enter the protruding portion 9 (shown by 8a in FIG. 2). In this case, it is preferable that the Si oxide layer 8 enters from the direction perpendicular to the direction in which the protruding portion 9 protrudes from the end face 1a (the stacking direction of the internal electrode layer 7). Bonding with the main body 1 can be strengthened not only in the longitudinal direction, which is the direction of the opposed external electrode 3 of the multilayer ceramic capacitor, but also in tension from the stacking direction.

  As described above, the main component material of the protrusion 9 is metal, while the Si oxide layer 8 is ceramic, but a part of the Si oxide layer 8 enters the protrusion 9. Further, the bonding between the protruding portion 8 and the Si oxide layer 8 existing in contact with the protruding portion 8 can be further strengthened, and the bonding strength of the external electrode, the failure in the high temperature and high humidity load test and the thermal shock test can be reduced. It can be further reduced.

  Further, according to the analysis using the X-ray microanalyzer, a part of the Si oxide layer 8 formed in the multilayer ceramic capacitor of the present embodiment is located on the side of the external electrode 3 from the region of the protrusion 9. There may be a case where an intruding portion (8b in FIG. 2) is recognized, whereby the bonding strength between the capacitor body 1 and the external electrode 3 can be further increased.

Note that the length of the protrusion 9 (distance from the end surface 1a of the capacitor body 1 to the bottom surface of the external electrode 3; t ₁ in FIG. 2) forms a gap between the end surface 1a of the capacitor body 1 and the external electrode 3. It is preferably 5 μm or less for the reason that it is difficult to be formed.

  Here, as a state in which the protruding portion 9 is alloyed, when the protruding portion 9 is subjected to a mapping process using an X-ray microanalyzer, both metals of the external electrode 3 and the internal electrode layer 7 are detected. Say.

  Further, the state in which the Si oxide layer 8 enters the protrusion 9 means that Si is detected in the region where the metal component of the protrusion 9 is detected in the Si mapping process using an X-ray microanalyzer. When it is done.

  In the multilayer ceramic capacitor of this embodiment, it is desirable that the total thickness t of the external electrode 3 and the plating film is 20 μm or less when the multilayer ceramic capacitor is viewed in a longitudinal section. Capacitors that contribute to the development of capacitance at the standard size of the multilayer ceramic capacitor by setting the total thickness t of the external electrode 3 and the plating film to 20 μm or less when the multilayer ceramic capacitor is viewed in a longitudinal section Since the volume of the main body 1 can be increased, the capacitance per unit volume of the multilayer ceramic capacitor can be increased. Even if the thickness of the external electrode 3 is so thin, in the case of the present invention, it is possible to obtain a multilayer ceramic capacitor having high bonding strength and excellent thermal shock resistance and resistance to a high temperature and high humidity test.

  Next, a method for producing the multilayer ceramic capacitor of the present invention will be described.

First, a dielectric ceramic material for forming the dielectric layer 5 is prepared. When a sintered body mainly composed of barium titanate is used as the dielectric ceramic, for example, a predetermined amount of MgO powder, rare earth element oxide powder, and MnCO ₃ powder are blended with the barium titanate powder, Furthermore, if necessary, glass powder is added as a sintering aid within a range in which desired dielectric properties can be maintained to obtain a raw material powder.

The proportions of MgO powder, rare earth oxide powder and MnCO ₃ powder are 0.2 to 0.8 mol, 0.3 to 0.8 mol and 0.1 to 0.1 mol, respectively, with respect to 100 mol of barium titanate powder. The addition amount of the glass powder is desirably 0.5 to 2 parts by mass when the barium titanate powder is 100 parts by mass.

Next, an organic vehicle is added to the above raw material powder to prepare a ceramic slurry, and then a ceramic green sheet is formed using a sheet forming method such as a doctor blade method or a die coater method. In this case, the thickness of the ceramic green sheet is preferably 0.5 to 4 μm for the purpose of securing a thin layer for increasing the capacity of the dielectric layer 5 and ensuring high insulation.

  Next, a rectangular internal electrode pattern is printed with a thickness of 1 to 3 μm on the main surface of the obtained ceramic green sheet. The conductor paste used as the internal electrode pattern is preferably composed mainly of at least one metal powder selected from Ni and Cu. In this case, the metal powder preferably has a purity of 98% or more, excluding the dielectric powder contained as a co-material.

  Next, stack the desired number of ceramic green sheets with internal electrode patterns, and stack multiple ceramic green sheets without internal electrode patterns on the top and bottom so that the upper and lower layers are the same number. Form the body. In this case, the internal electrode patterns in the sheet laminate are alternately shifted by a half pattern in the longitudinal direction.

Next, the sheet laminate is cut into a lattice shape to form a capacitor body molded body in which the end portions of the internal electrode patterns are exposed. After degreasing the capacitor body molded body, in a hydrogen-nitrogen mixed gas (oxygen partial pressure: 1 × 10 ⁻⁷ Pa to 1 × 10 ⁻⁹ Pa) at a temperature of 1100 ° C. to 1200 ° C. for 1 to 4 hours. The capacitor body 1 in which the dielectric layer 5 and the internal electrode layer 7 are integrally sintered is manufactured.

Next, the obtained capacitor body 1 is, if necessary, an oxygen partial pressure (oxygen partial pressure: 10) that is lower than the firing temperature (900 to 1050 ° C.) and higher than the firing reducing atmosphere. ^-4 Pa to 10 ^-6 Pa). In this case, the re-oxidation treatment can oxidize the dielectric layer 5 in a reduced state after firing, thereby enhancing the dielectric properties such as the relative dielectric constant of the dielectric layer 5.

  Next, the sintered capacitor body 1 is barrel-polished under predetermined conditions, the end surface 5a of the dielectric layer 5 is shaved to expose the internal electrode layer 7 to the end surface 1a of the capacitor body 1, and electrical connection with the external electrode 3 is performed. Make sure that you can make a good connection.

  In this case, it is preferable that the capacitor body 1 obtained by firing is placed in a ball mill using ceramic particles as media balls for barrel polishing.

  In the present invention, the size of the capacitor body 1 is not limited, but a small size of 0402 type (the area of the plane parallel to the internal electrode layer 7 is 0.4 mm × 0.2 mm) to 2012 type (the same area is 2 mm × 1 mm). This is suitable for multilayer ceramic capacitors.

Next, the external electrode 3 is formed on the end face of the capacitor body 1. As the conductor paste for the external electrode 3 constituting the multilayer ceramic capacitor of the present embodiment, for example, copper powder is mixed with a fine SiO ₂ powder, a solution containing lithium, and an organic vehicle containing an organic binder such as ethyl cellulose. Use the one prepared. In this case, the amount of the fine SiO ₂ powder contained in the conductor paste is preferably 3 to 10 parts by mass with respect to 100 parts by mass of the copper powder, and the fine SiO ₂ powder has an average particle size of 30 to 30 parts. It is good to use a 90 nm thing.

In the present embodiment, a solution containing lithium that easily softens the SiO ₂ powder is added to the fine SiO ₂ powder having a high surface energy as an inorganic component in the conductor paste for forming the external electrode 3. Therefore, the fine SiO ₂ powder easily diffuses from the external electrode 3 side to the end face 1a side of the capacitor body 1, and between the protruding portions 9 of the internal electrode layer 3 protruding to the end face 1a of the capacitor body 1. It becomes easy to enter. As a result, the Si oxide layer 9 can be formed between the dielectric layer 5 on the end face 1 a of the capacitor body 1 and the external electrode 3.

  In addition, since the conductive paste contains a lithium component that easily reacts at a low temperature in a liquid state, the melting point of the metal constituting the internal electrode layer 7 decreases, so that the metal of the internal electrode layer 7 and the metal of the external electrode 3 It becomes easy to react, and it becomes easy to form the protrusion part 9 which protruded in the end surface 1a of the capacitor | condenser main body 1. FIG.

In this case, when a conductor paste in which the proportion of the lithium-containing solution is increased with respect to the fine SiO ₂ powder, the bonding strength of the external electrode 3 to the capacitor body 1 can be increased, and the multilayer ceramic capacitor The electrostatic capacity of can be increased. This is presumably because the ratio of the alloy of the metal of the internal electrode layer 7 and the metal of the base electrode 3a increases in the protruding portion 9.

  In this case, the conditions for forming the external electrode 3 are preferably a maximum temperature of 600 to 750 ° C. and an oxygen partial pressure of 0.1 to 50 Pa.

  Next, by forming an Ni plating film and an Sn-containing plating film in this order on the surface of the base electrode 3a by electrolytic barrel plating, the multilayer ceramic capacitor of this embodiment can be obtained.

First, barium titanate powder, MgO powder, Y ₂ O ₃ powder and MnCO ₃ powder were prepared as raw material powders. These various powders when formed into a powdered barium amount of 100 moles titanate, 0.5 mol of MgO _powder, Y 2 _{O 3} powder was 0.5 mol per mol 1 mol, MnCO ₃ powder, further, the glass powder ( A dielectric powder was prepared by adding 1 part by mass of SiO ₂ = 55, BaO = 20, CaO = 15, Li ₂ O = 10 (mol%) to 100 parts by mass of barium titanate powder.

  This dielectric powder was wet mixed using a zirconia ball having a diameter of 5 mm and a mixed solvent composed of toluene and alcohol as a solvent.

  Next, the wet mixed powder is put into a mixed solvent of toluene and alcohol in which polyvinyl butyral resin is dissolved, and wet mixed using a zirconia ball having a diameter of 5 mm to prepare a ceramic slurry. Produced a ceramic green sheet having a thickness of 1.5 μm.

  Next, a plurality of rectangular internal electrode patterns mainly composed of Ni were formed on the upper surface of the ceramic green sheet. The conductor paste for forming the internal electrode pattern was obtained by adding 15 parts by mass of barium titanate (BT) powder to 100 parts by mass of Ni powder having an average particle size of 0.3 μm.

Next, 200 ceramic green sheets on which internal electrode patterns were printed were laminated, and 20 ceramic green sheets on which the internal electrode patterns were not printed were laminated on the upper and lower surfaces, respectively, using a press machine at a temperature of 60 ° C. and pressure The laminated body was produced by closely adhering under the conditions of 10 ⁷ Pa and 10 minutes, and then the laminated body was cut into a predetermined size to form a capacitor body molded body.

Next, after debinding the capacitor body molded body in the air, the capacitor body was baked at 1140 ° C. for 2 hours in a hydrogen-nitrogen mixed gas atmosphere at an oxygen partial pressure of 10 ⁻⁸ Pa. Produced. The size of the manufactured capacitor body corresponds to 1005 type, and the size was approximately 0.95 mm × 0.48 mm × 0.48 mm. Also,
The average thickness of the dielectric layer was 1 μm, and the average thickness of one internal electrode layer was 1 μm. The design value of the capacitance obtained with this capacitor body is 2.2 μF.

Next, the produced capacitor body was subjected to an oxidation treatment at 1000 ° C. for 5 hours in a nitrogen atmosphere (oxygen partial pressure: 10 ⁻⁶ Pa).

  Next, the produced capacitor body was barrel-polished. Barrel polishing was performed using a polypot having an internal volume of 500 mL, using alumina balls having an average particle diameter of 5 mm as media balls, and using pure water as a solvent. In each of the capacitor body samples subjected to barrel polishing, the internal electrode layer was slightly exposed from the end face of the capacitor body.

Next, a conductor paste (Cu powder (purity 99%)) containing Cu as a main component was applied to the end of the barrel-polished capacitor body to form an unsintered external electrode. As shown in Table 1, a paste containing Cu powder, fine SiO ₂ powder, a solution containing lithium, and an organic vehicle obtained by dissolving ethyl cellulose in a mixed solvent of terpineol and dibutyl phthalate is used. It was. Further, as a comparative example, a case where an SiO2 powder having an average particle diameter of 200 nm is used (sample No. 5 , 6 ) and a case where a borosilicate glass frit having a softening temperature of 680 ° C. is used (sample No. 7 ). A similar evaluation was made. SiO ₂ powder fine, the amount of the average particle size of 200 [mu] m SiO ₂ powder and borosilicate glass frit was 10 parts by mass with respect to Cu powder 100 parts by weight. Sample No. 4 is a reference example.

  Next, the capacitor body having an unsintered external electrode was heated under the conditions of a temperature of 700 ° C., an oxygen partial pressure of 1 Pa, and a maximum temperature holding time of 0.2 hours, and the base electrode was baked.

  Next, Ni plating and Sn plating are sequentially performed by electrolytic plating on the surface of the external electrode by electrolytic barrel plating to form a Ni plating film and a Sn-containing plating film (Sn 99.9%), and a multilayer ceramic capacitor Was made.

  Next, the following evaluation was performed on the produced multilayer ceramic capacitor. In addition, each evaluation was performed using the multilayer ceramic capacitor in which the Ni plating film and the Sn containing plating film were formed. At this time, the analysis of the protruding portion and the Si oxide layer at the interface portion between the capacitor body and the external electrode was performed by preparing a sample in which the obtained multilayer ceramic capacitor was polished to expose the cross section as shown in FIG. The results of the mapping process of each element using the X-ray microanalyzer attached to the scanning electron microscope are performed near the junction interface between the capacitor body and the external electrode.

  The state in which the protruding portion is alloyed is a case where both the metal of the external electrode and the internal electrode layer are detected when the protruding portion is subjected to a mapping process using an X-ray microanalyzer.

  The state in which the Si oxide layer has entered the protruding portion is a case where Si is detected in a region where the metal component of the protruding portion is detected in the Si mapping process using an X-ray microanalyzer.

  The thickness t of the external electrode was determined by measuring the thickness of the central portion of the capacitor body in the stacking direction from the copied scanning electron micrograph. The thickness of the external electrode formed at this time in the end face direction was about 18 μm for all samples. The Ni plating film and the Sn-containing plating film both had an average thickness of 1 μm.

The bonding strength of the external electrode to the capacitor body was such that a 0.8 mm solder-drawing wire was bonded to the external electrode of the sample with a eutectic cream solder on a 230 ° C. hot plate.
Bond strength was measured by pulling at mm / min. A sample having an average bonding strength of 1.5 kgf or higher was accepted, and a sample having an average bonding strength lower than 1.5 kgf was rejected.

  The thermal shock test is performed by immersing the multilayer ceramic capacitor in a solder tub for about 1 second using a solder tub set so that the temperature difference from room temperature is 300 ° C. Observation was made at a magnification of 50 to 100 times, and the presence or absence of cracks in any part of the external electrode and the capacitor body was confirmed, and the number of defects was determined.

In the high-temperature and high-humidity load test, a sample in which the insulation resistance of the multilayer ceramic capacitor showed 5 × 10 ⁷ Ω or less after standing for 48 hours under the conditions of a temperature of 65 ° C., a humidity of 93% RH, and a DC voltage of 6.3 V was determined to be defective did. The number of samples was 30.

  The capacitance was measured at a temperature of 25 ° C., a frequency of 1.0 kHz, and a measurement voltage of 1 Vrms, and the average value was obtained. The number of samples in the bonding strength, thermal shock test, and high temperature and high humidity load test was 30.

As is apparent from the results of Table 1, when the multilayer ceramic capacitor is viewed in a longitudinal section, Sample No. 1 having an Si oxide layer between the dielectric layer on the end face of the capacitor body and the external electrode is shown. 1
In -4, the number of defects in the bonding strength test was 1 or less out of 30. These samples all have a capacitance value of 2.1 μF or more, a value of 95% or more of the design value, no defects in the high temperature and high humidity load test, and defects in the thermal shock test. The rate was 1 or less out of 30.

  In particular, it was confirmed that the projecting portion formed an alloy of Ni of the internal electrode layer and Cu of the external electrode. In Nos. 2 to 4, the capacitance of the multilayer ceramic capacitor was 2.15 μF, and the variation was small compared to other samples.

  Furthermore, it was confirmed that the Si oxide layer had entered the protruding portion. In Nos. 2 and 3, there were no defects in any of the evaluations of bonding strength, thermal shock resistance, and high temperature and high humidity load characteristics.

  In contrast, sample no. In No. 5-7, there were many defects in evaluation of joining strength, thermal shock resistance, and high temperature and high humidity load characteristics.

DESCRIPTION OF SYMBOLS 1 Capacitor body 1a End surface of capacitor body 3 External electrode 5 Dielectric layer 7 Internal electrode layer 8 Si oxide layer 9 Projection

Claims (2)

A capacitor main body in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately laminated, and an external electrode provided on an end surface of the capacitor main body where the internal electrode layer is exposed and connected to the internal electrode layer. a multilayer ceramic capacitor comprising, when a multilayer ceramic capacitor was longitudinal sectional view, the capacitor body have a oxide layer of Si between the external electrode and the dielectric layer of the end face, wherein The internal electrode layer has a protruding portion protruding from the end face of the capacitor body, and a part of the Si oxide layer enters the protruding portion . 2. The multilayer ceramic capacitor according to claim 1 , wherein the protruding portion is an alloy of a metal of the internal electrode layer and a metal of the external electrode.

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