JP6696124B2 - Multilayer ceramic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a monolithic ceramic capacitor and a manufacturing method thereof, and more particularly to a monolithic ceramic capacitor having a small amount of hydrogen and a manufacturing method thereof.

  The monolithic ceramic capacitor is composed of a laminated body in which a plurality of dielectric layers and a plurality of internal electrodes are alternately laminated, and a pair formed on the surface of the laminated body so as to be electrically connected to the internal electrodes drawn out to the surface of the laminated body. External electrodes. The surface of the external electrode is plated with Ni to prevent solder erosion during mounting. Furthermore, in order to improve solderability during soldering mounting, the Ni plating film is formed on the Ni plating film. Sn plating is applied. The plating of Ni, Sn, etc. is usually formed by an electrolytic plating method.

  In Patent Document 1, hydrogen is generated due to a chemical reaction in a plating process, and this hydrogen is absorbed in the internal electrode, and the absorbed hydrogen gradually reduces the surrounding dielectric layer to deteriorate the insulation resistance. It is described that it causes problems such as letting. Then, as a means for solving the problem, when an internal electrode containing a noble metal (for example, Ag-Pd alloy) as a main component is used, a metal (for example, Ni) that suppresses absorption of hydrogen is added to the internal electrode. Has been done.

JP-A-1-80011

  However, in recent years, in order to reduce the material cost, a base metal such as Ni is often used as a material for the internal electrodes instead of a noble metal such as Ag and Pd.

Further, although Patent Document 1 describes that Ni is a “metal that inactivates absorption of hydrogen”, research by the inventors shows that Ni is used in the internal electrodes. Even if it exists, it is known that the insulation resistance is deteriorated by the influence of hydrogen.
Further, some base metals used as constituent materials for the internal electrodes and the external electrodes including the plating layer have a large ability to absorb hydrogen, such as Ni, and depending on the temperature conditions, release the absorbed hydrogen to some extent. It is known. In particular, when a high-temperature and high-humidity load test such as a PCBT test is performed, it is remarkably observed, and absorbed hydrogen is released and diffuses into the dielectric layer, resulting in deterioration of insulation resistance (IR). There is.

  Therefore, in order to avoid the adverse effects such as the deterioration of the insulation resistance caused by the fact that the monolithic ceramic capacitor contains hydrogen generated in the plating process, etc., the absolute amount of hydrogen contained in the monolithic ceramic capacitor should be reduced. Is desirable.

  The present invention solves the above problems, and by reducing the amount of hydrogen contained in a monolithic ceramic capacitor, it is possible to suppress the diffusion of hydrogen into the dielectric layer and prevent the deterioration of the insulation resistance. Another object of the present invention is to provide a monolithic ceramic capacitor and a manufacturing method thereof.

In order to solve the above problems, the multilayer ceramic capacitor of the present invention,
A dielectric layer made of a ceramic dielectric material, and a laminated body in which internal electrode layers containing a base metal as a main component are alternately laminated,
An external electrode having an external electrode body formed on the surface of the laminate so as to be electrically connected to the internal electrode drawn on the surface of the laminate, and an external electrode having a plating layer formed on the surface of the external electrode body. A monolithic ceramic capacitor comprising:
The external electrode body contains Cu,
At the joint between the external electrode body and the plating layer, a protective layer containing Cu ₂ O and CuO for suppressing the intrusion of hydrogen is provided,
When heat is applied to the laminate after removing the external electrodes at a temperature rising rate of 20 ° C./min to measure the amount of hydrogen generated from the laminate at a sampling cycle of 0.5 ° C. ,
The ratio (X / Y) of the hydrogen amount X generated in the range of 490 ° C. or higher and 510 ° C. or lower to the hydrogen amount Y generated in the range of 230 ° C. or higher and 250 ° C. or lower is 0.66 or lower,
The thickness of the protective layer is 0.1 μm or more and 1.5 μm or less,
The protective layer is present in 30% or more of the length direction of the joint portion between the external electrode body and the plating layer.

  Further, in the multilayer ceramic capacitor of the present invention, it is preferable that the plating layer is a composite plating layer including a Ni plating layer and an Sn plating layer formed on the Ni plating layer.

  In the case of the above configuration, the Ni plating layer that functions as a layer for preventing solder erosion during mounting and the Sn plating layer that functions to ensure wettability with solder during mounting are provided, and the insulation resistance It is possible to provide a monolithic ceramic capacitor which is free from deterioration and has excellent reliability.

  That is, for example, when the Ni plating layer is formed by electrolytic plating, hydrogen generated in the plating process may reach the internal electrode through the external electrode body and diffuse into the dielectric layer to deteriorate the insulation resistance. In the present invention, heat is applied to the laminated body after the external electrodes are removed, and when the amount of hydrogen generated from the laminated body is measured, the amount of hydrogen generated in a predetermined temperature range, other predetermined By defining the ratio to the amount of hydrogen generated in the temperature range, it is possible to efficiently prevent the deterioration of the insulation resistance due to the diffusion of hydrogen into the dielectric layer, and to obtain the highly reliable multilayer ceramic capacitor as described above. Will be able to provide.

Further, the manufacturing method of the multilayer ceramic capacitor of the present invention,
A laminated body forming step of forming a laminated body in which a dielectric layer made of a ceramic dielectric material and an internal electrode layer containing a base metal as a main component are alternately laminated,
An external electrode body forming step of forming an external electrode body containing Cu on the surface of the laminate so as to be electrically connected to the internal electrode drawn on the surface of the laminate;
An oxidation treatment step of performing oxidation treatment on the external electrode body under the condition that a protective layer containing Cu ₂ O and CuO and suppressing hydrogen intrusion is formed on the surface of the external electrode body;
On the surface of the external electrode body, an electrolytic plating step of forming a plating layer by electrolytic plating,
A ceramic body with a plating layer, which is a laminate in which the external electrode body and the plating layer are formed, is heat-treated under a temperature condition of 150 ° C. or higher, and is contained in the ceramic body with a plating layer in the electrolytic plating step. And a heat treatment step of releasing hydrogen to the outside ,
In the oxidation treatment step, the thickness is 0.1 μm or more and 1.5 μm or less, and the protective layer is formed in 30% or more of the length direction of the joint between the external electrode body and the plating layer. Is characterized in that the above-mentioned oxidation treatment is carried out .

Further, in the method for manufacturing a multilayer ceramic capacitor of the present invention,
The electrolytic plating step is a step of forming a Ni plating layer on the surface of the external electrode body by electrolytic plating, and
After the heat treatment step, it is preferable to include a step of forming a Sn plating layer on the surface of the Ni plating layer by electrolytic plating.

  After the Ni plating layer is formed on the surface of the external electrode body by the electrolytic plating method, heat treatment is performed, and then the Sn plating layer is formed to make it less susceptible to the hydrogen generated in the Ni plating step. A Ni plating layer that can suppress deterioration of insulation resistance and that functions as a layer that prevents solder erosion during mounting, and an Sn plating layer that functions to ensure wettability with solder during mounting. It is possible to obtain a multilayer ceramic capacitor having high reliability.

In the laminated ceramic capacitor according to the present invention , heat is applied to the laminated body after the external electrodes are removed at a temperature rising rate of 20 ° C./min to measure the amount of hydrogen generated from the laminated body at a sampling cycle of 0.5 ° C. In this case, the ratio (X / Y) of the hydrogen amount X generated in the range of 490 ° C. or higher and 510 ° C. or lower to the hydrogen amount Y generated in the range of 230 ° C. or higher and 250 ° C. or lower becomes 0.66 or lower. It is configured such that the amount of hydrogen in the laminated body (ceramic element body), which causes deterioration of the dielectric layer, is reduced.
As a result, it is possible to provide a highly reliable multilayer ceramic capacitor capable of preventing deterioration of insulation resistance.

In the multilayer ceramic capacitor of the present invention, the external electrode body comprises Cu, the bonding portion of the external electrode body and the plating layer, viewed including the Cu ₂ O and CuO, comprises suppressing protective layer intrusion of hydrogen Therefore, it is possible to suppress and prevent hydrogen from entering the laminated body through the external electrode body, so that it is possible to obtain a more reliable laminated ceramic capacitor.

In the present invention, the amounts of hydrogen X and Y include both hydrogen (hydrogen gas (H ₂ )) with m / z = 2 and hydrogen (hydrogen existing as hydrogen ions or hydrogen atoms) with m / z = 1. It includes. Generally, the amount of hydrogen at m / z = 2 and the amount of hydrogen at m / z = 1 can be obtained by TDS analysis (Thermal Desorption Spectrometry).
According to the research conducted by the inventors, the hydrogen causing the deterioration of the insulation resistance is presumed to be hydrogen having m / z = 1 and m / z = 2. However, in the present invention, hydrogen is mainly used. Attention was paid to the amount of hydrogen (hydrogen gas) at / z = 2.

Further, in the method for manufacturing a laminated ceramic capacitor according to the present invention, after forming a plating layer on the surface of the external electrode body by electrolytic plating, the ceramic body with a plating layer, which is a laminated body in which the external electrode body and the plating layer are formed. The body is heat-treated under a temperature condition of 150 ° C. or higher to release at least a part of hydrogen contained in the ceramic body with a plating layer to the outside in the electrolytic plating step, which causes deterioration of the dielectric layer. It becomes possible to reduce the amount of hydrogen contained in the ceramic element body with a plating layer and partially absorbed by the internal electrode.
As a result, it is possible to prevent deterioration of the insulation resistance and reliably manufacture a highly reliable multilayer ceramic capacitor.
Further, since the external electrode body is oxidized under the condition that the protective layer containing Cu ₂ O and CuO is formed on the surface of the external electrode body to suppress the invasion of hydrogen, hydrogen is emitted from the external electrode body. It is possible to obtain a monolithic ceramic capacitor capable of suppressing the intrusion into the laminated body through the above.

It is a front sectional view showing a configuration of a monolithic ceramic capacitor according to an embodiment of the present invention. FIG. 6 is a diagram for explaining the method for manufacturing the multilayer ceramic capacitor according to the embodiment of the present invention, and is a diagram showing a state where a Ni plating layer is formed on the surface of the external electrode body by an electrolytic plating method. FIG. 4 is a diagram for explaining a method for manufacturing a laminated ceramic capacitor according to an embodiment of the present invention, showing a laminated body (a ceramic body with an Ni plated layer) in which a Ni plated layer is formed on a surface of an external electrode body. It is a figure which shows the state currently heat-processed typically. It is a figure which shows the relationship between temperature and the amount of hydrogen in TDS analysis about the sample without heat processing. It is a figure which shows the relationship between the temperature and the amount of hydrogen in TDS analysis about the sample heat-processed at 85 degreeC. It is a figure which shows the relationship between the temperature and the amount of hydrogen in TDS analysis about the sample heat-processed at 150 degreeC. It is a figure which shows the relationship between the temperature and the amount of hydrogen in TDS analysis about the sample heat-processed at 600 degreeC. It is a figure which shows the relationship between the temperature and the amount of hydrogen in TDS analysis about the sample which heat-processed above 150 degreeC and changed the baking conditions of an external electrode.

  Hereinafter, the features of the present invention will be described in more detail by showing embodiments of the present invention.

  FIG. 1 is a front sectional view showing the structure of a monolithic ceramic capacitor 1 according to an embodiment of the present invention.

  The laminated ceramic capacitor 1 includes a laminated body (ceramic element body) 11 including a dielectric layer 10 made of a ceramic dielectric material and a plurality of internal electrodes 12 laminated via the dielectric layer 10, and a laminated body. A pair of external electrodes 13 arranged so as to be electrically connected to the internal electrodes 12 that are alternately drawn out are provided on a pair of end faces 11 a of the plurality of electrodes 11.

  The external electrode 13 includes an external electrode body 13a formed so that a part thereof wraps around the side face 11b from the end surface 11a of the laminated body 11, a Ni plating layer 13b formed so as to cover the surface of the external electrode body 13a, and a Ni plating layer 13b. The Sn plating film 13c formed so as to cover the surface of the plating layer 13b is provided.

As a material forming the dielectric layer 10, for example, a dielectric ceramic containing BaTiO ₃ as a main component is used. Besides, CaTiO ₃ , SrTiO ₃ , CaZrO ₃ or the like can be used.

  As the conductive material forming the internal electrodes 12, for example, a base metal containing Ni as a main component is used. Besides, Cu or the like can be used.

The external electrode body 13a is a so-called baked electrode formed by, for example, applying a conductive paste containing metal powder (Cu powder in this embodiment) and glass to the end surface 11a of the stacked body 11 and baking the conductive paste. .. In this embodiment, Cu is used as the conductive material forming the external electrode body 13a, but Ag, Ni, or the like can also be used. Further, a conductive resin electrode other than the baking electrode may be used.
The thickness of the external electrode body 13a is not particularly limited, but is, for example, 10 to 50 μm.

Further, the Ni plating layer 13b is formed by an electrolytic plating method so as to cover the surface of the external electrode body 13a.
The thickness of the Ni plating layer 13b is not particularly limited, but is 3 to 5 μm, for example.

Further, the Sn plating layer 13c is formed by an electrolytic plating method so as to cover the surface of the Ni plating layer 13b.
The thickness of the Sn plating layer 13c is also not particularly limited, but is 3 to 5 μm, for example.

Further, as shown in FIG. 1, a protective layer 20 containing Cu ₂ O and CuO is provided at the joint between the external electrode body 13a and the Ni plating layer 13b .

Then, in the monolithic ceramic capacitor 1 configured as described above , when the amount of hydrogen generated from the laminated body 11 is measured by applying heat to the laminated body 11 after the external electrode 13 is removed, it is 490 ° C. or higher and 510 The ratio (X / Y) of the amount X of hydrogen generated in the range of 0 ° C or lower to the amount Y of hydrogen generated in the range of 230 ° C or higher and 250 ° C or lower is set to 0.66 or lower .

  As described above, when heat is applied to the laminated body 11 to measure the amount of hydrogen generated from the laminated body 11, the hydrogen amount X generated in the range of 490 ° C. or higher and 510 ° C. or lower is 230 ° C. or higher and 250 By configuring the ratio (X / Y) with respect to the amount Y of hydrogen generated in the range of ℃ or less to be 0.66 or less, hydrogen in the internal electrode 12, which causes deterioration of the dielectric layer 10, is reduced. It is possible to obtain a monolithic ceramic capacitor having a small amount, that is, a monolithic ceramic capacitor capable of preventing deterioration of insulation resistance.

  The monolithic ceramic capacitor 1 is provided with a Ni plating layer 13b which is provided so as to cover the external electrode body 13a and functions as a layer for preventing solder erosion during mounting. The Sn plating layer 13c is provided so as to cover the layer 13b and has a function of ensuring wettability with solder during mounting. Therefore, according to the present invention, it is possible to prevent the insulation resistance from deteriorating and realize a monolithic ceramic capacitor having high mounting reliability.

Further, as described above, the multilayer ceramic capacitor 1 of this embodiment is provided with the protective layer 20 containing Cu ₂ O and CuO at the joint between the external electrode body 13a and the Ni plating layer 13b. It is possible to suppress and prevent hydrogen from entering the inside through the main body 13a, and it is possible to provide a more reliable multilayer ceramic capacitor.

  The protective layer 20 preferably has a thickness of 0.1 μm or more and 1.5 μm or less.

  The presence of the protective layer 20 can be confirmed by analysis using energy dispersive X-ray spectroscopy (EDX) of a transmission electron microscope (TEM). It should be noted that a particularly large effect can be obtained when the external electrode body 13a and the Ni plating layer 13b are present in 30% or more of the lengthwise direction of the joint portion (interface).

  The presence of 30% or more of the length of the joint (interface) in the longitudinal direction means that the existence of the protective layer 20 is confirmed with respect to the length (distance) of the joint (interface) observed. It means that the ratio of the total distance (total length) is 30% or more.

Next, a method of manufacturing the monolithic ceramic capacitor 1 will be described.
(1) Preparation of Laminate First, a ceramic green sheet having an internal electrode pattern formed by applying a conductive paste for forming an internal electrode on the surface, and a ceramic green sheet having no internal electrode pattern for an outer layer A laminated body (ceramic element body) 11 as shown in FIG. 2 is obtained by cutting a laminated block formed by laminating and pressure-bonding sheets in a predetermined order, dividing into individual chips, and firing. To make.

The laminated body 11 may be chamfered by a method such as barrel polishing.
There are no particular restrictions on the method for producing the laminate 11, and various known methods can be used.

(2) Formation of External Electrode Main Body The external electrode main body 13a is formed by applying a conductive paste containing Cu powder, metal powder, and glass to the end surface 11a of the laminate 11 and firing it. There are no particular restrictions on firing conditions.
The thickness of the external electrode body 13a was about 15 μm at the center of the end face.

(3) oxidation process Next, the external electrode body 13 formed by performing oxidation treatment on the surface of the external electrode body 13a, to produce a protective layer 20 (FIG. 1) including the Cu ₂ O and CuO.
The oxidation treatment is performed under the following conditions, for example.
(A) Temperature condition: 50 ° C. or more and 900 ° C. or less (b) Atmosphere condition: Oxygen concentration 30 ppm or more and 50 ppm or less (c) Time condition: 1 minute or more, 120 minutes or less Further, the oxidation treatment is performed after the following heat treatment. It is also possible.

(3) Formation of Ni Plating Layer Next, Ni electrolytic plating is performed to form the Ni plating layer 13b so as to cover the surface of the external electrode body 13a. Thereby, the laminated body (hereinafter, also referred to as “ceramic element body with Ni plating layer”) 14 including the external electrode body 13a and the Ni plating layer 13b is obtained.
The thickness of the Ni plating layer 13b was about 3 μm.
Hydrogen is generated in the Ni electrolytic plating step, and a part of the generated hydrogen enters the inside of the laminated body (ceramic body) 11 via the external electrode body 13a as schematically shown in FIG. The inner electrode 12 is also reached.

(4) Heat treatment As described above, the laminated body (ceramic element body 14 with the Ni plating layer) on which the Ni plating layer 13b is formed by the electrolytic plating method is heat treated in a temperature range of 150 ° C or higher.
The heat treatment is carried out, for example, by placing the Ni-plated layer-coated ceramic body 14 in an oven for a predetermined time (for example, 60 minutes).
As a result of this heat treatment, the hydrogen contained in the Ni-plated ceramic body 14 and partially absorbed by the internal electrodes passes through the external electrode body 13a and the Ni plated layer 13b, as schematically shown in FIG. It is released to the outside of the ceramic body 14 with the Ni plating layer.
By performing this heat treatment, it is possible to obtain a monolithic ceramic capacitor that can reduce the amount of hydrogen contained in the laminated body 11, suppress the diffusion of hydrogen into the dielectric layer, and prevent the deterioration of the insulation resistance. it can.

(5) Formation of Sn Plating Layer Then, as shown in FIG. 3, the Sn plating layer 13c was formed on the outer surface of the Ni plating layer 13b by an electrolytic plating method. Here, the thickness of the Sn plating layer 13c was about 3 μm.
Even when the Sn plating film layer 13c is formed by electrolytic plating, some hydrogen may be generated in the electrolytic plating step. However, in the heat treatment step described above, hydrogen contained in the Ni-plated ceramic body 14 is not contained. Since hydrogen is released to the outside, the effect of hydrogen is smaller than in the past.

<Evaluation test>
In order to evaluate the monolithic ceramic capacitor 1 produced in this embodiment, (1) the monolithic ceramic capacitor of Sample No. 1 in Table 1 produced without heat treatment of the laminate (ceramic element body 14 with Ni plating layer) ( sample),
(2) Laminates of sample numbers 2 to 4 in Table 1 produced by performing heat treatment on the laminate (ceramic element body 14 with Ni plating layer) at different temperatures of 85 ° C., 150 ° C., and 600 ° C. Ceramic capacitor (sample)
Prepared.

The monolithic ceramic capacitors (samples) of Sample Nos. 1 to 4 in Table 1 all have an Sn plating layer on the Ni plating layer.
The samples (multilayer ceramic capacitors) of sample numbers 1 to 4 have a capacitance of 2.2 μF, a rated voltage of 6.3 V, a dimension of 0.6 to 0.7 mm, and a width of 0.3 to 0. 4 mm, height 0.3 to 0.4 mm, thickness of the external electrode body (thickness of substantially central region of end face of ceramic body) 15 μm, thickness of Ni plating layer 3 μm, thickness of Sn plating layer 3 μm is there.

Then, for each sample of the above-mentioned sample Nos. 1 to 4 in which the heat treatment conditions are different and the hydrogen content is adjusted, when heat is applied to the laminated body after the external electrodes are removed,
(A) Hydrogen amount X generated in the temperature range of 490 ° C. or higher and 510 ° C. or lower,
(B) Amount of hydrogen Y generated in a temperature range of 230 ° C. or higher and 250 ° C. or lower,
I checked.

  In measuring the hydrogen amounts X and Y generated in the temperature range of 490 ° C. or higher and 510 ° C. or lower and the temperature range of 230 ° C. or higher and 250 ° C. or lower, first, the external electrode and the plating film are removed by a method such as polishing. The prepared sample was prepared.

Then, the generation behavior of hydrogen at m / z = 2 was investigated by TDS analysis (Thermal Desorption Spectrometry). The conditions for TDS analysis were a temperature rising rate of 20 ° C./min, a maximum temperature of 700 ° C., a hydrogen generation amount sampling interval of 0.5 ° C., and the number of evaluation samples: 10 each.
The quantification method is as follows.

1) Arithmetically average the amount of hydrogen generated in the temperature range of 230 ° C or higher and 250 ° C or lower. The value calculated here is defined as the hydrogen amount Y. However, the hydrogen generation amount may be a negative value depending on the state of the analyzer. In that case, except that, the arithmetic average is performed.

2) Next, the amount of hydrogen generated in the temperature range of 490 ° C. or higher and 510 ° C. or lower is arithmetically averaged. The value calculated here is defined as the hydrogen amount X. However, the hydrogen generation amount may be a negative value depending on the state of the analyzer. In that case, except that, the arithmetic average is performed.

3) Then, the ratio (X / Y) of the hydrogen amount X to the hydrogen amount Y is obtained from the hydrogen amount X and the hydrogen amount Y obtained as described above.
Table 1 shows the ratio (hydrogen generation ratio) (X / Y) of the hydrogen amount X to the hydrogen amount Y of each sample obtained as described above.

In addition, FIGS. 4 to 7 are diagrams showing the results of TDS analysis of the samples subjected to the heat treatment under the following conditions. That is,
(A) FIG. 4 is a diagram showing a relationship between temperature and hydrogen content in TDS analysis of a sample without heat treatment,
FIG. 5 is a diagram showing the relationship between temperature and hydrogen content in TDS analysis of a sample heat-treated at 85 ° C.
FIG. 6 is a diagram showing the relationship between temperature and hydrogen content in TDS analysis for a sample heat-treated at 150 ° C.,
FIG. 7 is a diagram showing a relationship between temperature and hydrogen amount in TDS analysis of a sample heat-treated at 600 ° C.,
FIG. 8 is a diagram showing the relationship between the temperature and the hydrogen content in the TDS analysis for a sample that was heat-treated at 150 ° C. or higher and the firing conditions of the external electrodes were changed.

From FIGS. 4 to 7, when the ratio (X / Y) of the hydrogen amount X generated in the range of 490 ° C. or higher and 510 ° C. or lower to the hydrogen amount Y generated in the range of 230 ° C. or higher and 250 ° C. or lower is calculated, The ratios shown in Table 1, that is,
Without heat treatment: X / Y = 0.74
When the heat treatment temperature is 85 ° C .: X / Y = 0.67
When the heat treatment temperature is 150 ° C .: X / Y = 0.55
When the heat treatment temperature is 600 ° C .: X / Y = 0.36
It was confirmed that
Further, from FIG. 8, the ratio (X / Y) of the hydrogen amount X generated in the range of 400 ° C. to 420 ° C. to the hydrogen amount Y generated in the range of 230 ° C. to 250 ° C. is calculated. It was confirmed that when the temperature was 150 ° C. or higher: X / Y = 0.66.

The hydrogen amounts X and Y in this evaluation test are the amounts of hydrogen (hydrogen detected as hydrogen gas (H ₂ )) at m / z = 2.
In the present invention, as in the case of this embodiment, attention may be paid to the amount of hydrogen (hydrogen gas) of m / z = 2, and hydrogen may be paid attention to the amount of hydrogen of m / z = 1. The behavior of may be known.

In addition, after heat treatment, a PCBT test (high temperature and high humidity load test) was performed on the samples of sample numbers 1 to 4 in which the Sn plating layer was formed on the Ni plating layer.
The PCBT test was performed under the conditions of 125 ° C./95% RH / 3.2V / 72 hr. In the PCBT test, the number of evaluation samples was 20 for each of the samples 1 to 4.

Then, when the insulation resistance (IR) of each sample was measured and observed by LogIR, the case where the IR value at the end of the test decreased by 0.5 from the IR value at the start of the test was regarded as the sample having IR deterioration. It was
Table 1 also shows the results of the PCBT test, that is, the number of samples (the number of failures) in which the insulation resistance has deteriorated among the 20 evaluation samples provided for each test.

  In Table 1, sample Nos. 3 and 4 are samples that satisfy the requirements of the present invention, and sample Nos. 1 and 2 are samples that do not satisfy the requirements of the present invention.

  As shown in Table 1, in the case of the sample of Sample No. 1 without heat treatment and the sample of Sample No. 2 heat-treated at 85 ° C. (sample not satisfying the requirements of the present invention), a range of 490 ° C. or higher and 510 ° C. or lower It was confirmed that the ratio (X / Y) of the amount X of hydrogen generated in the above to the amount Y of hydrogen generated in the range of 230 ° C. or higher and 250 ° C. or lower was more than 0.66.

  Further, in the case of the sample of Sample No. 1 that does not satisfy the requirements of the present invention (the sample that has not been heat-treated), the number of defects generated in the PCBT test is 20, and it is confirmed that defects are generated in all the samples. It was also confirmed that the number of defects in the PCBT test was as large as 11 in the sample No. 2 as well.

  On the other hand, in the samples of Sample Nos. 3 and 4 (samples satisfying the requirements of the invention) that were heat-treated at 150 ° C. and 600 ° C., the hydrogen amount X generated in the range of 490 ° C. or higher and 510 ° C. or lower was 230. It was confirmed that the ratio (X / Y) to the amount Y of hydrogen generated in the range of ℃ or more and 250 ℃ or less was a value of 0.66 or less.

  Then, in the case of the samples Nos. 3 and 4 (samples satisfying the requirements of the present invention and having (X / Y) of 0.66 or less), it was confirmed that the number of occurrences of defects was not recognized in the PCBT test. ..

  From these results, after forming a Ni plating layer on the surface of the external electrode body by electrolytic plating, the Ni plating layer-provided ceramic body is heat-treated under a temperature condition of 150 ° C. or higher to obtain the Ni plating layer-coated ceramic body. By releasing hydrogen that is partly absorbed in the internal electrodes, etc., to the outside, the amount of hydrogen that causes deterioration of the dielectric layer is reduced, and insulation resistance is not deteriorated. It was confirmed that a highly reliable multilayer ceramic capacitor can be obtained.

In the above embodiment, the case where the Ni plating layer is formed on the surface of the external electrode main body has been described as an example, but the present invention is not limited to the Ni alloy plating layer and other than Ni, such as Cu, Pd, It can also be applied to a monolithic ceramic capacitor provided with a plating layer of Au, Cr, Zn, Pt, Ag, Fe, an alloy containing these, or the like.
Further, in the above-described embodiment, the case where the external electrode body is a Cu baking electrode has been described as an example, but the present invention is not limited to the case where the external electrode body is a Ni or Ag baking electrode or the external electrode body is baked. The present invention can also be applied to the case of a resin electrode containing a conductive component instead of the electrode.

  Further, although the Sn plating layer is formed as the plating layer formed on the surface of the Ni plating layer in the above embodiment, a solder plating layer or the like may be formed in addition to the Sn plating layer described above. It is possible. Further, in addition to the Sn plating layer and the solder plating layer, it is possible to form a Pd plating layer, a Cu plating layer, an Au plating layer and the like.

  The present invention is not limited to the above embodiment, and various applications and modifications can be added within the scope of the invention.

1 Multilayer Ceramic Capacitor 10 Dielectric Layer 11 Multilayer (Ceramic Element)
11a End face of laminated body 12 Internal electrode 13 External electrode 13a External electrode body 13b Ni plating layer 13c Sn plating layer 14 Ceramic body with Ni plating layer

Claims (4)

A dielectric layer made of a ceramic dielectric material, and a laminated body in which internal electrode layers containing a base metal as a main component are alternately laminated,
An external electrode having an external electrode body formed on the surface of the laminate so as to be electrically connected to the internal electrode drawn on the surface of the laminate, and an external electrode having a plating layer formed on the surface of the external electrode body. A monolithic ceramic capacitor comprising:
The external electrode body contains Cu,
At the joint between the external electrode body and the plating layer, a protective layer containing Cu ₂ O and CuO for suppressing the intrusion of hydrogen is provided,
When heat is applied to the laminate after removing the external electrodes at a temperature rising rate of 20 ° C./min to measure the amount of hydrogen generated from the laminate at a sampling cycle of 0.5 ° C. ,
The ratio (X / Y) of the hydrogen amount X generated in the range of 490 ° C. or higher and 510 ° C. or lower to the hydrogen amount Y generated in the range of 230 ° C. or higher and 250 ° C. or lower is 0.66 or less,
The thickness of the protective layer is 0.1 μm or more and 1.5 μm or less,
The multilayer ceramic capacitor, wherein the protective layer is present in 30% or more of a length direction of a joint portion between the external electrode body and the plating layer.   The multilayer ceramic capacitor according to claim 1, wherein the plating layer is a composite plating layer including a Ni plating layer and a Sn plating layer formed on the Ni plating layer. A laminated body forming step of forming a laminated body in which a dielectric layer made of a ceramic dielectric material and an internal electrode layer containing a base metal as a main component are alternately laminated,
An external electrode body forming step of forming an external electrode body containing Cu on the surface of the laminated body so as to be electrically connected to the internal electrode drawn on the surface of the laminated body;
An oxidation treatment step of oxidizing the external electrode body under the condition that a protective layer containing Cu ₂ O and CuO is formed on the surface of the external electrode body to suppress entry of hydrogen;
On the surface of the external electrode body, an electrolytic plating step of forming a plating layer by electrolytic plating,
A ceramic body with a plating layer, which is a laminate in which the external electrode body and the plating layer are formed, is heat-treated under a temperature condition of 150 ° C. or higher, and is contained in the ceramic body with a plating layer in the electrolytic plating step. And a heat treatment step of releasing hydrogen to the outside,
In the oxidation treatment step, the thickness is 0.1 μm or more and 1.5 μm or less, and the protective layer is formed in 30% or more of the length direction of the joint between the external electrode body and the plating layer. A method for manufacturing a monolithic ceramic capacitor, comprising: The electrolytic plating step is a step of forming a Ni plating layer on the surface of the external electrode body by electrolytic plating, and
The method for manufacturing a multilayer ceramic capacitor according to claim 3, further comprising a step of forming an Sn plating layer on the surface of the Ni plating layer by electrolytic plating after the heat treatment step.

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