JP6070287B2 - Ceramic multilayer electronic components - Google Patents

Description

  The present invention relates to a terminal electrode structure of a ceramic multilayer electronic component.

  In recent years, due to the progress of car electronics and the like, the environmental resistance performance required for ceramic multilayer electronic components has become increasingly severe. In connection with this, the electrical insulating high temperature load reliability of the ceramic electronic component may be required to have a higher temperature and longer time characteristics, for example, a reliability of 1000 hours at 155 ° C.

  The ceramic multilayer electronic component has a laminate in which an element body and internal electrodes are alternately laminated, and a terminal electrode so as to be connected to the internal electrode. This terminal electrode is formed by applying a conductive paste containing a glass component to the end face where the internal electrode is exposed and baking it to form a base electrode, and forming a metal layer such as nickel or tin thereon by plating. . However, the plating solution may enter the electronic component during the plating. When the invading plating solution is subjected to a voltage load at a high temperature, the plating solution components are ionized and move and diffuse inside the electronic component due to the electric field generated by the voltage, causing deterioration of electrical insulation. .

  Therefore, in order to prevent the plating solution from entering the inside of the electronic component during plating, a technique for forming a glass layer on the exposed surface of the laminate not covered with the terminal electrodes has been proposed (Patent Document 1). ).

Japanese Patent Laid-Open No. 2005-5412

  However, even in the case of a ceramic laminated electronic component in which the exposed surface of the laminated body is glass-coated by the method of the prior art, it is poor in the electrical insulation high temperature load reliability of 1000 hours for a long time at a higher temperature of 155 ° C. Was found to occur. As a result of diligent investigation of this cause, the inventors of the present invention, when plating on the base electrode, the plating solution dissolves the glass component contained in the base electrode and penetrates into the base electrode, and further into the laminate. It has been found that the intrusion occurs due to migration of the components of the plating solution when a voltage is applied at a high temperature.

  The present invention has been made in view of the above, and prevents the plating solution from penetrating into the base electrode and entering the inside of the laminate, and is superior in electrical insulating high temperature load reliability. An object is to provide a laminated electronic component.

  In order to solve the above-described problems and achieve the object, the ceramic multilayer electronic component according to the first means has a laminated body, a terminal electrode composed of a base electrode containing a metal and a glass component, and a plated metal layer. It is a ceramic multilayer electronic component. Further, the base electrode is composed of a surface region and an intermediate region, the glass component of the surface region contains zirconia, and the content of zirconia in the glass component of the surface region is the amount of zirconia in the glass component of the intermediate region. More than the content.

  When applying the plating metal layer of the base electrode, increasing the content of zirconia in the glass component contained in the surface region allows the plating solution to dissolve the glass component of the base electrode during plating, thereby stacking ceramic multilayer electronic components. Intrusion into the body can be prevented. As a result, it is possible to provide a ceramic multilayer electronic component that is electrically insulating and excellent in high-temperature load reliability.

  The ceramic multilayer electronic component according to the second means is the ceramic multilayer electronic component according to the first means, wherein the content of zirconia in the glass component of the surface region of the base electrode is an average of the intermediate region of the base electrode. More than 30% by mass is more preferable than the value. This further improves the chemical resistance of the glass component in the surface region of the base electrode, and more effectively prevents the plating solution from dissolving the glass component of the base electrode and entering the inside of the electronic component.

  In the ceramic multilayer electronic component according to the third means, in the ceramic multilayer electronic component according to the first means or the second means, the exposed surface of the laminate is formed with a glass layer containing zirconia. Is preferred. As a result, it is possible to simultaneously suppress the plating solution from dissolving the element body and entering the inside of the electronic component, and the reliability of the electronic component can be further improved.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that plating solution penetrate | invades into a base electrode, and penetrate | invades into a laminated body, and can provide the ceramic multilayer electronic component excellent in electrical insulation high temperature load reliability.

It is a perspective view which shows schematic structure of a ceramic multilayer electronic component. It is a ceramic multilayer electronic component in this embodiment, and is sectional drawing of the II line | wire of FIG. It is a figure which shows the measurement area | region of a zirconia in the ceramic multilayer electronic component in this embodiment. FIG. 4 is a diagram showing a measurement result of zirconia in the base electrode of Example 1. FIG. 10 is a diagram showing measurement results of zirconia in the base electrode of Example 8.

  Hereinafter, preferred embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

  Description will be made using the ceramic multilayer electronic component according to the present embodiment. FIG. 1 is a perspective view showing an example of a multilayer ceramic electronic component 1 according to this embodiment. The ceramic multilayer electronic component 1 according to the present embodiment includes a multilayer body 4 and terminal electrodes 7 on the end surfaces thereof.

2 is a cross-sectional view taken along the line II of the ceramic multilayer electronic component 1 shown in FIG. The ceramic multilayer electronic component 1 of FIG. 2 has a multilayer body 4 including a base body 2 made of ceramics and a plurality of internal electrodes 3, in other words, a unit structure in which the base body 2 and the internal electrodes 3 are stacked. 9 is provided. More specifically, the internal electrodes 3 having end portions exposed on one surface of the laminate 4 and the internal electrodes 3 having end portions exposed on the other surface of the laminate 4 are alternately laminated. . Base electrodes 5 are provided on both surfaces of the laminate 4 so as to cover the surfaces. The base electrode 5 is electrically connected to the group of internal electrodes 3 exposed from one surface of the multilayer body 4 or the group of internal electrodes 3 exposed from the other surface of the multilayer body 4. A plated metal layer 6 is provided on the surface of the base electrode 5.

  As shown in FIGS. 1 and 2, the terminal electrode 7 is a terminal electrode main surface 7 a that covers the surface of the laminate 4 where the end of the internal electrode 3 (not shown in FIG. 1) is exposed. The terminal electrode side surface 7b covers a part of the surrounding surface, that is, a part of the side surface so as to go around from the terminal electrode main surface 7a. Furthermore, the terminal electrode 7 is comprised from the base electrode 5 and the plating metal layer 6, as shown in FIG. The base electrode 5 serves as a base for forming the plated metal layer 6 and ensures adhesion between the terminal electrode 7 and the laminate 4.

  The element body 2 of the ceramic multilayer electronic component 1 is made of ceramics, specifically, semiconductor ceramics, dielectric ceramics, and magnetic ceramics.

  The internal electrode 3 is preferably made of a material mainly composed of silver, palladium, nickel, copper, or aluminum from the viewpoint of enabling reliable ohmic contact with the element body 2, There is no particular limitation on the material.

  The base electrode 5 has a structure having a glass component containing a metal component and zirconia. Such a structure can be obtained, for example, by applying a conductive paste to the surface portion where the end portion of the internal electrode 3 of the multilayer body 4 is exposed and baking it. The conductive paste for forming the base electrode 5 mainly includes a glass powder (frit) containing zirconia, an organic vehicle (binder), and a metal powder. By firing the conductive paste, The organic vehicle is volatilized, and finally the base electrode 5 containing a glass component and a metal component is formed. In addition, you may add various additives, such as a viscosity modifier, an inorganic binder, and an oxidizing agent, to an electrically conductive paste as needed. For example, the base electrode 5 includes at least one of silver, copper, nickel, or zinc as a metal component.

  As shown in FIG. 2, the base electrode 5 includes a surface region 5a and an intermediate region 5b of the base electrode. In the present embodiment, the zirconia content of the glass component is greater in the surface region 5a of the base electrode 5 than in the intermediate region 5b. The zirconia content of the glass component increases the chemical resistance when the content is increased. For this reason, when the base electrode 5 is plated, the glass component is corroded by the plating solution, and an effect of preventing the plating solution from penetrating the base electrode 5 and entering the ceramic multilayer electronic component can be obtained. It is.

  As a result of intensive studies by the inventors, it has been found that the main penetration point of the plating solution into the ceramic multilayer electronic component is a path through which the base electrode 5 penetrates. At the time of plating, cations such as alkali metals other than metal elements gather around the base electrode 5 due to the electric field for plating in the plating solution. For this reason, the plating solution around the base electrode 5 becomes highly alkaline, and the glass component of the base electrode 5 is actively melted, and an open void leading to the laminate 4 is formed in the base electrode 5. Plating solution enters through. For this reason, according to this invention, the main penetration | invasion location of plating solution can be interrupted | blocked effectively.

  However, if the amount of zirconia in all the glass components contained in the base electrode 5 is increased uniformly, the softening temperature of the glass components increases and the sintering temperature increases. For this reason, the crystal grain diameter of the metal constituting the base electrode 5 becomes large, the grain boundary becomes coarse, and the plating solution tends to enter from here, which is not preferable. On the other hand, when only the zirconia content of the glass component of the surface region 5a of the base electrode 5 is increased, the composition of the glass component of the base electrode 5 as a whole is fired at the same temperature as that of the glass component of the intermediate region 5b of the base electrode. Can do. In addition, the chemical resistance that suppresses the elution of the glass component by the plating solution of the base electrode 5 is determined by the composition of the glass component of the surface region 5a of the base electrode 5, and thus by such a configuration, the firing temperature is raised. Therefore, the chemical resistance of the base electrode 5 can be improved.

  The content of the surface region 5a of the base electrode 5 is preferably 20% by mass or more and more preferably 30% by mass or more than the content of the intermediate region 5b. Most preferably, the content of the surface region 5a of the base electrode 5 is 40 mass% or more higher than the content of the intermediate region 5b.

  The production method for increasing the surface region 5a more than the intermediate region 5b can be obtained by using the following method, for example, as the zirconia content of the glass component of the base electrode 5. Prepare two types of composition of the glass component of the conductive paste used as the base electrode 5 (paste H) and a small amount (paste L) of the zirconia so that the end of the internal electrode 3 of the laminate 4 is exposed. The paste H, paste L, and paste H are applied three times in the order of paste H, paste L, and paste H, and baked.

  The zirconia content of the base electrode 5 can be evaluated by measuring the distribution in the depth direction of the base electrode 5 in the following measurement region. FIG. 3 shows a measurement region 8 of the base electrode 5 in the cross section of the ceramic multilayer electronic component 1 shown in FIG. The measurement region 8 is a region including the center of the thickness with a thickness of 1/2 of the stacked body 4 when viewed from the stacking direction in the cross section. Further, the measurement region 8 is a region surrounded by a perpendicular line T from the line segment W from the laminate 4 to the plated metal layer 6 in parallel with the line segment W in contact with the laminate 4 and the lamination direction of the laminate 4. is there.

Next, surface analysis of the zirconium element and the metal component of the base electrode 5 is performed on the measurement region 8 using EPMA (Electron Probe Micro Analyzer). The detected amounts of zirconium element in the line segment W direction are averaged to obtain a distribution in the T direction. Similarly, the distribution of the metal component detection amount in the thickness T direction is obtained, and the detection amount of the zirconium element at each depth is divided by the detection amount of the metal component of the base electrode 5. Furthermore, the coefficient is determined so that the average value of zirconia contained in the glass component of the base electrode 5 is the same as the average value contained in the glass component in the base electrode paste, by multiplying the detected amount of zirconium by a certain coefficient. The detected amount of zirconium × coefficient is defined as the content of zirconia (ZrO ₂ ) contained in the glass component.

  The surface region 5 a of the base electrode 5 in the measurement region 8 has a thickness from the interface between the multilayer body 4 and the base electrode 5 to the plated metal layer 6, that is, 1/6 of the thickness of the base electrode 5. The surface region 5a on the 4th side, and a thickness of 1/6 of the thickness of the base electrode 5 from the interface with the plated metal layer 6 becomes the surface region 5a on the plated metal layer 6 side. Further, in the base electrode 5 other than the measurement region 8, the surface region 5 a defined in the measurement region 8 can be extended to be the surface region 5 a of the base electrode 5. The base electrode 5 other than the surface region 5a is defined as an intermediate region 5b.

  The content of zirconia in the surface region 5a and the intermediate region 5b of the base electrode 5 is the average value of the content of zirconia in the surface region 5a and the intermediate region 5b in the measurement region 8 as the content in that region.

  Furthermore, when the zirconia content is different between the surface region 5a on the laminate 4 side and the surface region 5a on the plated metal layer 6 side, the value with the smaller zirconia content is set to the content of zirconia in the surface region 5a. Amount.

  The plating metal layer 6 has, for example, a two-layer structure including a nickel plating metal layer 6a and a tin plating metal layer 6b that are stacked from the base electrode 5 side. The nickel-plated metal layer 6a prevents contact between the molten solder and the base electrode 5 during mounting, and prevents solder erosion. The thickness is about 2 μm, for example. The thicker the nickel plated metal layer 6a, the more the solder erosion can be suppressed, but the productivity decreases. When the nickel plating metal layer 6a is formed by electroplating, the stress increases if the layer is made too thick, and between the nickel plating metal layer 6a and the base electrode 5 or between the base electrode 5 and the laminate 4. Separation may occur between the two.

  The nickel plating metal layer 6a is preferably formed by electroplating. As the plating apparatus, an electric barrel plating apparatus is preferably used. In this case, it is possible to perform plating by inserting metal balls called chips and media into a non-conductive net called a bucket and inserting a cathode called a tumbler into the mixture while rotating the balls.

  The kind of the nickel plating solution is preferably a Watt bath or a nickel sulfamate plating solution. The deposited film from the Watt bath has good adhesion to the substrate, and is semi-glossy and corrosion resistant. The composition of the Watt bath is nickel sulfate hexahydrate 200 to 380 g / L, nickel chloride hexahydrate 30 to 60 g / L, and boric acid 30 to 45 g / L. Usually, the pH is 1.5 to 5 and the temperature is 40 to 70 ° C., and the pH adjuster is preferably nickel carbonate.

  The composition of the nickel sulfamate plating solution is usually nickel sulfamate tetrahydrate 350 to 450 g / L, boric acid 30 to 40 g / L, nickel bromide 3 to 10 g / L, pH 4 to 4.5, temperature 40 Used at ~ 60 ° C. As the pH adjuster, nickel carbonate is used as in the Watts bath.

  The tin-plated metal layer 6b has a function of improving the wettability of solder, and the thickness thereof is, for example, about 4 μm. The tin plated metal layer is also preferably formed by electric barrel plating.

  The tin plating solution includes alkaline tin plating solution (stannate bath) having a pH of 12 or more, acidic tin plating solution having a pH of 2 or less, and neutral tin plating solution having a pH of 4-8. In many cases, there is a problem in chemical resistance, and since the element body is corroded with both strong alkali and strong acid, a neutral tin plating solution is preferable.

  Examples of the composition of the neutral tin plating solution include 40 to 60 g / L of tin methanesulfonate as a tin salt, 30 to 50 g / L of ammonium methanesulfonate as a conductive salt, and 150 to 250 g / L of sodium gluconate as a chelating agent. Examples include those in which L is added and the pH is adjusted to 4 with ammonia.

  When a large current flows through the terminal electrode 7 as in a power device or the like, it is also preferable to provide a copper plating metal layer between the base electrode 5 and the nickel plating metal layer 6 a in the plating metal layer 6. Since copper has a small electrical resistance, the resistance of the terminal electrode can be lowered to suppress heat generation during use of the electronic component. The thickness of the copper plating metal layer is preferably 1 to 4 μm. Moreover, electroplating is preferable as the method for forming the copper plating metal layer. An example of the composition of the electrolytic copper plating solution is a copper pyrophosphate plating solution having a pH of 8.

  In another ceramic electronic component of the present embodiment, a glass layer is formed on the exposed surface of the laminate 4, whereby the plating solution during plating corrodes the element 2 of the laminate 4 and It is possible to prevent the strength from decreasing. Further, since the glass layer is an insulator, it is possible to prevent the plating metal layer from being deposited on the exposed surface of the laminate 4 during electroplating when the resistance of the element body 2 is low.

  The element body 2 may contain zinc. In this case, in particular, since the chemical resistance of the element body 2 tends to be low, it is more preferable to form a glass layer.

  As an example of the element body 2 containing zinc, a low melting point containing zinc as a main component of the element body 2 in semiconductor varistors and thermistors, and as a sintering aid for the element body 2 in dielectric ceramics and magnetic ceramics. Glass is preferably used. In particular, in the latter case, the thickness of the ceramic multilayer component has been reduced with the downsizing of the ceramic laminated part. For this reason, there has been an increasing demand for lowering the sintering temperature, and the number of usage examples has further increased.

  In particular, the trend of miniaturization is remarkable in multilayer coils and chip capacitors of ceramic multilayer parts, and for this reason, there are many demands for lowering the sintering temperature of materials. For this reason, it is preferable to add a low melting point glass containing zinc as a sintering aid. In this case, although the sintering temperature is particularly lowered, the strength and chemical resistance of the element body 2 tend to be lowered.

  Examples of the method for forming the glass layer include a sputtering method, an electron beam evaporation method, a thermal CVD method, a plasma CVD method, a method of spraying and heating a glass slurry, a dip method, and a sol-gel method.

  The composition of the glass layer preferably contains zirconia in consideration of chemical resistance. The content of zirconia is preferably 3% by mass or more, more preferably 5% by mass or more, and most preferably 10% by mass or more. Further, the alkali oxide content is preferably 10% by mass or less and the zinc oxide content is preferably 5% by mass or less in order to improve chemical resistance. For the same reason, the melting point of the glass is 650 ° C. or more. Preferably there is. The latter is because the higher the melting point of the glass, the better the chemical resistance. An alkali-free glass containing no alkali oxide is preferable because it has high migration resistance and does not lower the specific resistance of the glass layer in a high-temperature moisture resistance test.

  In order to ensure the continuity of the glass layer, the glass layer is preferably amorphous. Crystallized glass has the merit of preventing sticking of chips during firing, but the glass layer tends to be porous, and the plating solution may enter the inside of the laminate during plating.

[Example 1]
210 multilayer ceramic capacitor chip laminates 4 having an outer dimension of 1.0 × 0.5 × 0.5 mm were prepared. Here, the element body is made of strontium titanate, and the element body sandwiched between the internal electrodes has a thickness of 2 μm. The internal electrode is made of a silver / palladium alloy and has a thickness of 1 μm. Further, the surface of the laminate is not covered with glass.

Next, 70% by mass of silver powder, 7% by mass of glass powder, and the remainder is a binder and solvent base electrode paste. It apply | coated so that it might become 6 micrometers. The composition of this glass powder is 53% by mass of silicon dioxide (SiO ₂ ), 15% by mass of diboron trioxide (B ₂ O ₃ ), 12% by mass of sodium oxide (Na ₂ O), and zirconia (ZrO ₂ ). 15% by mass, zinc oxide (ZnO) is 3% by mass, and other components are 2% by mass. Hereinafter, this base electrode paste is abbreviated as paste H.

Further thereon, 70% by mass of silver powder, 7% by mass of glass powder, and the rest were applied with a base electrode paste consisting of a binder and a solvent so that the thickness after drying was 24 μm. The composition of this glass powder is 53% by mass of silicon dioxide (SiO ₂ ), 15% by mass of diboron trioxide (B ₂ O ₃ ), 12% by mass of sodium oxide (Na ₂ O), and zirconia (ZrO ₂ ). 7% by mass, zinc oxide (ZnO) is 3% by mass, and other components are 10% by mass. Hereinafter, this base electrode paste is abbreviated as paste L.

  Further, paste H was applied thereon to the same thickness and baked (baked) at 680 ° C. for 10 minutes to form a base electrode into a laminate. The thickness of the base electrode after firing was 30 μm in total. In other words, for the base electrode, the paste H was used for the laminate-side paste and the plating metal-side paste, and the paste L was used therebetween.

  Next, 100 chips after the base electrode is baked are arbitrarily extracted, a nickel plating metal layer is formed on the base electrode by electric barrel plating, and a tin plating metal layer is further formed thereon by 4 μm. Got the chips. Incidentally, the nickel plating solution used was a Watt bath having a pH of 4 and a solution temperature of 50 ° C., and the tin plating solution was a neutral bath having a pH of 6.

  Ten chips (ceramic multilayer electronic components) after terminal plating were arbitrarily extracted, and a cross section was obtained in a direction perpendicular to the stacking direction at the center of the chip.

  A region having a width of 250 μm at the center in the same direction as the stacking direction of the stacked body in the base electrode portion in the cross section was taken as a measurement region. This measurement region was subjected to surface analysis of the composition of zirconium and silver of the metal component of the base electrode. The mass% of the zirconium element with respect to the silver element was evaluated in the thickness direction as the zirconia content in the glass component. Incidentally, in the width direction, which is the same direction as the lamination direction of the laminate, the zirconia content in the thickness direction was averaged. Further, FIG. 5 shows the result showing the distribution of the zirconia content in the base electrode portion of the cross section obtained by averaging 10 chips.

  Next, the average value of the zirconia content from 0 to 5 μm corresponding to the region having a depth of 1/6 of the thickness of the base electrode from the interface with the laminate is obtained as the zirconia content in the surface region on the laminate side, the plating metal The average value from 5 to 25 μm corresponding to the region from 1/6 to 5/6 of the thickness of the base electrode from the interface with the layer is defined as the zirconia content in the intermediate region, and further from the interface with the plated metal layer to the base electrode An average value of 25 to 30 μm corresponding to a region having a depth of 1/6 of the thickness was defined as the zirconia content in the surface region on the plated metal side. Then, the smaller one of the zirconia content in the surface region on the plated metal layer side and the zirconia content in the surface region on the laminate side was defined as the zirconia content in the surface region, and compared with the content in the intermediate region. The results are shown in Table 1.

In the electrical insulation high-temperature addition test, 100 chips before terminal plating and 100 chips after terminal plating were used, and a voltage of 5 V was continuously applied between the terminal electrodes in an atmosphere of 155 ° C. Then, the change in insulation resistance was evaluated. The average time obtained from the Weibull plot of the time when the inter-terminal resistance at 155 ° C. decreased to 10 ⁷ Ω or less was defined as the life time.

  The lifetime of the chip after terminal plating in Example 1 was 2530 hours, and a long lifetime of 1000 hours or more was obtained. Moreover, when the lifetime in the high temperature load test of 100 chips before terminal plating was evaluated by the same method, it was 2470 hours. For this reason, it was confirmed that the lifetime after plating did not decrease.

[Example 2]
In Example 2, it carried out like Example 1 except having changed the composition of the glass powder of the paste H. The composition of the glass powder was changed to 13% by mass of zirconia, and other compositions were adjusted without changing the ratio of each component. The results are shown in Table 1.

Example 3
In Example 3, it carried out similarly to Example 1 except having changed the composition of the glass powder of the paste H. The composition of the glass powder was changed to 11.5% by mass of zirconia, and the other compositions were adjusted without changing the ratio of each component. The results are shown in Table 1.

Example 4
In Example 4, it carried out like Example 1 except having changed the composition of the glass powder of the paste H. The composition of the glass powder was changed to 8.5% by mass of zirconia, and other compositions were adjusted without changing the ratio of each component. The results are shown in Table 1.

Example 5
In Example 5, it carried out like Example 1 except having changed the composition of the glass powder of the paste H. The composition of the glass powder was changed to 8% by mass of zirconia, and other compositions were adjusted without changing the ratio of each component. The results are shown in Table 1.

Example 6
In Example 6, it carried out like Example 1 except having changed the composition of the glass powder of the paste H. The composition of the glass powder was changed to 7% by mass of zirconia, and the other compositions were adjusted without changing the ratio of each component. The results are shown in Table 1.

Example 7
In Example 7, it carried out like Example 1 except having changed the composition of the glass powder of the paste H. The composition of the glass powder was changed to 6.5% by mass of zirconia, and other compositions were adjusted without changing the ratio of each component. The results are shown in Table 1.

  From the results of Examples 1 to 7, it was found that when the zirconia content in the surface region of the base electrode was larger than the content in the intermediate region, the lifetime of the high temperature load test was 1000 hours or more. In addition, it was found that when the zirconia content in the surface region of the base electrode is 30% by mass or more than the content in the intermediate region, the lifetime of the high temperature load test is longer than 2000 hours.

Example 8
In Example 8, 6 μm of paste H, 9 μm of paste L, 6 μm of paste H, 9 μm of paste L, and 6 μm of paste H are applied to the surface where the internal electrode of the laminate is exposed, and the base electrode is baked. The same operation as in Example 1 was performed except that the operation was performed at 710 ° C. for 10 minutes. Incidentally, the baking temperature here was raised at 680 ° C. for 10 minutes in Example 1 because the firing of the base electrode was insufficient. The results are shown in Table 1.

  The lifetime was 2120 hours, and a lifetime of 1000 hours or more was obtained. It can be seen that even if there is a region with a lot of zirconia in the intermediate region, if the content of zirconia in the surface region is 30% or more higher than the content of the intermediate region, the life veteran of the high temperature load test will be 2000 hours or more. It was. Furthermore, the result which shows distribution of zirconia content in the base electrode part of a cross section is shown in FIG.

Example 9
In Example 9, the material of the element body is changed from a strontium titanate type to a varistor mainly composed of zinc oxide (ZnO), the material of the internal electrode is palladium, and the exposed surface of the laminate is the same as the glass component of the paste H. The same procedure as in Example 1 was performed except that a glass layer having a composition of 3 μm in thickness was formed.

  The life time of the high temperature load test was as good as 2830 hours. Even if it is a varistor composed mainly of zinc oxide, which has poor chemical resistance, the glass layer is formed on the exposed surface of the laminate, and the zirconia content in the surface region of the base electrode is the content of the intermediate layer. More than 20%, it was confirmed that the life of the high temperature load test could be 2000 hours or more.

[Comparative Example 1]
Comparative Example 1 was performed in the same manner as in Example 1 except that the base electrode was formed to a thickness of 30 μm using only the paste L. The results are shown in Table 2.

[Comparative Example 2]
In Comparative Example 2, the same process as in Example 1 was performed except that the base electrode was changed to paste L instead of using paste H as the paste on the plated metal layer side. The results are shown in Table 2.

[Comparative Example 3]
In Comparative Example 3, the same procedure as in Example 1 was performed except that the base electrode was changed to paste L instead of using paste H as the laminate-side paste. The results are shown in Table 1.

[Comparative Example 4]
Comparative Example 4 was performed in the same manner as in Example 1 except that paste L was not used as the base electrode paste, paste H was stacked, and the baking temperature was increased to 790 ° C. The results are shown in Table 2.

  From Comparative Examples 1 to 4, it was confirmed that the lifetime of the high-temperature load test was less than 1000 hours when the zirconia content in the surface region of the base electrode was smaller than the content in the intermediate region.

  As described above, the ceramic multilayer electronic component according to the present invention is useful for improving high temperature load reliability.

DESCRIPTION OF SYMBOLS 1 ... Ceramic laminated electronic component 2 ... Element body 3 ... Internal electrode 4 ... Laminated body (sintered body)
DESCRIPTION OF SYMBOLS 5 ... Base electrode 5a ... Surface region of base electrode 5b ... Middle region of base electrode 6 ... Metal plating layer 6a ... Nickel plating metal layer 6b ... Tin plating metal layer 7 ... Terminal electrode 7a ... Main surface of terminal electrode 7b ... Terminal electrode 8 ... EPMA analysis area 9 ... Unit structure

Claims (3)

A laminate, a base electrode containing a metal and a glass component, and a terminal electrode composed of a plated metal layer;
The base electrode is composed of a surface region and an intermediate region, the glass component of the surface region contains zirconia, and the content of zirconia in the glass component of the surface region is zirconia in the glass component of the intermediate region. A ceramic multilayer electronic component characterized by being greater in content.   2. The ceramic multilayer electronic component according to claim 1, wherein a content of zirconia in the glass component in the surface region is 30 mass% or more higher than a content of zirconia in the glass component in the intermediate region. 3. The ceramic multilayer electronic component according to claim 1, wherein a glass layer containing zirconia is formed on an exposed surface of the laminate.

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