JP6070288B2 - Ceramic multilayer electronic components - Google Patents

Description

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

  When a ceramic multilayer electronic component mounted on a circuit board is subjected to a rapid thermal change such as a heat cycle test or placed in such a harsh environment, the element body, terminal electrodes, solder, circuit Cracks may occur in the element body due to thermal stress caused by differences in thermal expansion coefficients of the substrates and the like, and as a result, the ceramic multilayer electronic component may not function. In recent years, with the progress of car electronics, the above-mentioned problems have become more serious, and the thermal shock resistance required for electronic components has become increasingly severe.

  Therefore, in order to solve this problem, in Patent Document 1, in the external electrode of the multilayer ceramic capacitor, a conductive epoxy system containing a metal powder between an electrode layer coated with a conductive paste and baked, and a Ni plating layer A technique has been proposed in which the formation of a thermosetting resin layer suppresses cracking of the capacitor body and peeling of external electrodes due to thermal shock after circuit board mounting.

Japanese Patent Application Laid-Open No. 11-162771

  According to the technique disclosed in Patent Document 1, when a conductive epoxy thermosetting resin layer is formed between the base electrode and the plated metal layer, the thermal stress caused by the shrinkage of the solder and the circuit board can be alleviated. According to this example, the cooling / heating cycle of −55 to 150 ° C. was performed 1000 times in the multilayer ceramic capacitor, and no cracks in the main body or peeling of the external electrodes occurred. However, with the progress of car electronics, the thermal shock resistance required for ceramic electronic parts has become more severe, and when a more rapid and frequent resistance, for example, a thermal shock of −55 ° C. to 155 ° C. is repeated 2000 cycles. However, it is required that there is no problem in reliability. When such a large thermal shock is repeatedly applied, cracks may still occur at the interface between the laminate and the base electrode even if the technique of Patent Document 1 is used. This is because the thermal expansion coefficient of the base electrode is generally twice or more that of the element body, and it is considered that cracks are generated due to the thermal stress caused by this.

  The present invention has been made in view of the above, and an object thereof is to provide a ceramic multilayer electronic component having excellent thermal shock resistance.

In order to solve the above-described problems and achieve the object, a ceramic multilayer electronic component according to a first means includes a laminate, a base electrode including 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 bismuth oxide, and the content of bismuth oxide in the glass component of the surface region is More than the content of bismuth oxide in the glass component.
As a result, the viscosity during firing of the glass component contained in the surface region of the base electrode decreases, and when the thermal shock is applied by diffusing into the surface region of the element body to strengthen the adhesion between the base electrode and the laminate. Prevents the generation of cracks.

  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 bismuth oxide in the glass component of the surface region of the base electrode is contained in the intermediate region of the base electrode. It is preferable that it is 20 mass% or more than the amount. As a result, the viscosity at the time of firing the glass component contained in the surface region of the base electrode was further reduced and diffused into the surface region of the base body to further strengthen the adhesion between the base electrode and the laminate, and a thermal shock was applied. The occurrence of cracks is further effectively prevented.

  In the ceramic laminated electronic component according to the third means, in the ceramic laminated electronic component according to the first means or the second means, the exposed surface of the element body is preferably coated with glass. Thereby, at the time of forming the plating metal layer, it is possible to simultaneously suppress the plating solution from corroding the element body and lowering the strength of the laminated body, thereby further improving the thermal shock resistance of the electronic component.

    According to the present invention, it is possible to suppress the occurrence of cracks when a thermal shock is applied to a ceramic multilayer electronic component.

1 is a perspective view showing a schematic structure of a ceramic multilayer electronic component in one embodiment of the present invention. It is sectional drawing of the II line | wire of FIG. It is a ceramic multilayer electronic component in another embodiment of this invention, and is sectional drawing of the II line | wire at the time of forming a glass layer in the exposed surface of the element | base_body of FIG. It is a figure which shows the measurement area | region of a bismuth oxide in FIG. It is a figure which shows the measurement result of the depth direction distribution of bismuth oxide in the base electrode of Example 1. It is a figure which shows the measurement result of the depth direction distribution of bismuth oxide 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.

  As an example of the ceramic electronic component according to the present embodiment, an example of a ceramic multilayer electronic component is shown. FIG. 1 is a perspective view showing an example of a ceramic multilayer electronic component according to this embodiment. 2 is a cross-sectional view taken along the line II of FIG.

  The ceramic multilayer electronic component 1 has a multilayer body 4 including an element body 2 made of ceramics and a plurality of internal electrodes 3. In other words, at least a unit structure 11 in which the element body 2 and the internal electrodes 3 are laminated is provided. It has one. 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, and each of the base electrodes 5 is a group of internal electrodes 3 exposed from one surface of the laminate 4 or a laminate. 4 is electrically connected to the group of internal electrodes 3 exposed from the other surface.

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

  For the internal electrode 3, for example, a material mainly composed of Ag, Pd, Ni, Cu, or Al is used from the viewpoint of enabling reliable ohmic contact with the element body 2. There is no limitation.

  As shown in FIG. 1, the terminal electrode 7 includes a terminal electrode main surface 7 a that covers the surface of the laminate 4 where the end of the internal electrode 3 is exposed, and a part of the surrounding surface, that is, The terminal electrode side surface 7b covers a part of the side surface so as to go around from the terminal electrode main surface 7a. As shown in FIG. 2, the internal structure of the terminal electrode 7 includes a base electrode 5 and a plated metal layer 6. The base electrode 5 serves as a base when the plated metal layer 6 is formed, and ensures adhesion between the terminal electrode 7 and the laminate 4.

  The base electrode 5 has a structure including a metal component and a glass component. Such a structure is obtained, for example, by applying and baking a conductive paste on a surface portion where the end of the internal electrode 3 of the laminate 4 is exposed. The conductive paste for forming the base electrode 5 mainly includes a glass powder (frit), an organic vehicle (binder), and a metal powder. By firing the conductive paste, the organic vehicle is The base electrode 5 that volatilizes and finally contains 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 Ag, Cu, Ni, or Zn as a metal component.

  The glass component of the base electrode 5 contains bismuth oxide. As shown in FIG. 2, when the base electrode 5 is divided into the surface region 5a and the intermediate region 5b of the base electrode and compared, the content of bismuth oxide in the glass component of the surface region 5a of the base electrode is the base electrode. More than the content of bismuth oxide in the glass component of the intermediate region 5b. When the content of bismuth oxide in the glass component of the surface region 5a is large, the viscosity of the glass component during firing decreases, and the glass component penetrates into the surface region of the element body 2 at the interface between the laminate 4 and the base electrode 5. Thus, the adhesion between the laminate 4 and the base electrode 5 is increased. Moreover, since the viscosity of the glass component at the time of baking is low, a glass component fully flows in the surface area | region of a base electrode, and generation | occurrence | production of an open void is suppressed. As a result, the plating solution penetrates into the base electrode from the open void during terminal plating, reaches the interface with the laminate, dissolves the peripheral glass components, and decreases the adhesion between the base electrode and the laminate. Can be prevented. As a result, even when subjected to severe thermal shock, the electrical characteristics of the electronic component can be maintained without causing cracks at the interface between the laminate 4 and the base electrode 5.

  The content of bismuth oxide in the glass component is preferably 20% by mass or more, more preferably 30% by mass or more in the surface region 5a of the base electrode than in the intermediate region 5b. Most preferably, the content of the surface region 5a of the base electrode is 40% by mass or more than the content of the intermediate region 5b.

  On the other hand, if the amount of bismuth oxide in all the glass components contained in the base electrode 5 is increased, the softening temperature of the glass component is lowered, the viscosity during sintering of all the glass components contained in the base electrode is lowered, and the glass component is the base. It flows out to the electrode surface and a fixing failure occurs. In order to avoid this, if the sintering temperature (firing temperature) is lowered, then the viscosity during sintering of all glass components contained in the base electrode will increase, and the glass component will be at the interface between the laminate and the base electrode. The adhesion between the laminate and the base electrode is reduced. In addition, since the glass component does not flow sufficiently in the surface area of the base electrode, open voids are generated, and the plating solution penetrates into the base electrode from the open voids during terminal plating, reaches the interface with the laminate, and the peripheral part. This is not preferable because the glass component is dissolved and the adhesion between the base electrode and the laminate is lowered. When only the bismuth oxide content of the glass component in the surface region 5a of the base electrode 5 is increased, the glass component composition of the entire base electrode 5 may be fired at the same temperature as in the glass component composition of the intermediate region 5b of the base electrode. Is possible. In addition, since the chemical resistance of the base electrode 5 is determined by the glass component composition of the surface region 5a of the base electrode, the above-described configuration improves the chemical resistance of the base electrode 5 as a whole without increasing the sintering temperature. I can do it.

  The method for producing the base electrode in which the bismuth oxide content is higher in the surface region 5a of the base electrode than in the intermediate region 5b of the base electrode is not particularly limited. Two types of base electrode paste having a large amount of bismuth oxide (paste H) and a small amount (paste L) in the composition of the glass component are prepared, and the end of the internal electrode of the laminate 4 is exposed. The paste H, paste L, and paste H are repeatedly applied three times in this order and fired.

The bismuth oxide content in each region of the base electrode 5 is evaluated by measuring the depth direction distribution of the base electrode 5 as follows. For the cross section of FIG. 3, first, the measurement region 9 of the base electrode is determined. First, the measurement region 9 takes a length of ¼ from the middle point of the boundary line 8 where the laminate 4 and the base electrode 5 are in contact to both ends, and is ½ of the total length of the boundary line 8. Determine the line segment W. A range surrounded by the perpendicular T and the line W extending from the end point of the line segment toward the interface between the plating base electrode 5 and the metal layer 6 is defined as a measurement region 9. Next, a surface analysis of the bismuth content is performed on the measurement region 9 with EPMA. The detected amounts of bismuth 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 bismuth at each depth is divided by the detection amount of the metal component of the base electrode 5. Furthermore, the content of bismuth oxide (Bi ₂ O ₃ ) is obtained by multiplying the detected amount of bismuth by a certain coefficient determined by calibration.

  In addition, when there are a plurality of metal components of the base electrode 5, it is divided by the sum. In addition, when bismuth is contained in the metal component, the surface analysis of the metal component as the main component is performed, and this is multiplied by a certain coefficient corresponding to the content of bismuth in the metal component, from the surface analysis value of bismuth. Otherwise, the distribution in the depth direction of bismuth in the glass component is calculated in the same manner. The reason for dividing by the detected amount of the metal component of the base electrode 5 is that the amount of the glass component relative to the metal component of the base electrode 5 may not be uniform within the base electrode. Based on this, the average value of the detected amount of bismuth oxide from the boundary line 8 between the laminate 4 and the base electrode 5 to the depth of 1/6 of the thickness of the base electrode 5 is taken as the content of the surface region on the laminate side, The average value of the detected amount of bismuth oxide from the interface with the plated metal layer 6 to the depth of 1/6 of the thickness of the base electrode 5 is defined as the content of the surface region on the plated metal layer side. The smaller of the two is defined as the bismuth oxide content of the surface region 5a. Further, the average value of the area other than the above-described surface area, that is, the area from the interface with the plated metal layer 6 to 1/6 to 5/6 of the thickness of the base electrode 5 is defined as the content of bismuth oxide in the intermediate area 5b.

  The plated metal layer 6 has, for example, a two-layer structure including a Ni plated metal layer 6a and a Sn plated metal layer 6b that are stacked from the base electrode 5 side. The Ni-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. As the Ni plating metal layer 6a is made thicker, the solder erosion can be suppressed, but the productivity is lowered. Further, when the Ni-plated metal layer 6a is formed by electroplating, the stress increases when the layer is made too thick, and peeling occurs between the Ni-plated metal layer 6a and the base electrode 5 or between the base electrode 5 and the laminate 4. May occur.

  The Ni plating metal layer 6a is preferably formed by electroplating. As the plating apparatus, an electric barrel plating apparatus is preferably used. In this case, a metal ball called a chip and a medium is put into a non-conductive net called a bucket, and a cathode called a tumbler is inserted into the mixture while rotating to perform plating. Electrons are supplied from the tumbler to the base electrode of the chip through the medium, and Ni is deposited on the base electrode 5.

  As the type of the Ni plating solution, a Watt bath or a sulfamic acid Ni plating solution is preferably used. 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 200 to 380 g / L of sulfuric acid Ni hexahydrate, 30 to 60 g / L of Ni chloride hexachloride, and 30 to 45 g / L of boric acid. Usually, the pH is 1.5 to 5 and the temperature is 40 to 70 ° C., and the pH adjuster is preferably Ni carbonate.

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

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

  The Sn plating solution includes an alkaline Sn plating solution (Sn salt bath) having a pH of 12 or more, an acidic Sn plating solution having a pH of 2 or less, and a neutral Sn plating solution having a pH of 4 to 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 Sn plating solution is preferable.

  Examples of the composition of the neutral Sn plating solution include 40 to 60 g / L of methanesulfonic acid Sn as the Sn salt, 30 to 50 g / L of ammonium methanesulfonate as the conductive salt, and 150 to 250 g / L of sodium gluconate as the 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 Cu plating metal layer between the base electrode 5 and the Ni plating metal layer 6 a in the plating metal layer 6. Since Cu has a small electric resistance, the resistance of the terminal electrode can be lowered to suppress heat generation during use of the electronic component. The thickness of the Cu plating metal layer is preferably 1 to 4 μm. Further, electroplating is preferable as a method for forming the Cu plating metal layer. An example of the composition of the electric Cu plating solution is a copper pyrophosphate plating solution having a pH of 8.

  FIG. 4 shows a cross-sectional view taken along line II of another example of the ceramic electronic component of the present embodiment. In FIG. 4, the glass layer 10 is formed on the exposed surface of the element body, which can prevent the plating solution during plating from corroding the element body and reducing the strength of the element body. Moreover, since glass is an insulator, it is possible to prevent the plating from being deposited on the exposed surface of the element during electroplating when the resistance of the element is low.

  The element body 2 may contain Zn. In this case, since the chemical resistance of the element body is lowered, it is preferable to form the glass layer 10.

  As an example of an element body containing Zn, low melting glass containing Zn as a sintering aid is preferably used as a main component such as a varistor and thermistor in semiconductor ceramics, and as a sintering aid in dielectric ceramics and magnetic ceramics. In particular, in the latter case, the thickness of the ceramic multilayer component has been reduced with the reduction in the size of the ceramic laminated part. For this reason, the sintering temperature has been further lowered, and the number of usage examples has further increased.

  In particular, ceramic electronic components such as multilayer coils and chip capacitors are prominent in miniaturization. For this purpose, it is necessary to lower the sintering temperature of the material. In order to achieve this, it is preferable to add a low melting point glass such as zinc as a sintering aid. In this case, the sintering temperature decreases, but the strength and chemical resistance of the element body 2 tend to decrease.

  Examples of the method for forming the glass layer 10 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 dipping method, a sol-gel method, and the like.

  The composition of the glass layer 10 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 in a high-temperature moisture resistance test.

  In order to ensure the continuity of the glass layer 10, 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]
110 laminated bodies of laminated coils having outer dimensions of 1.0 × 0.5 × 0.5 mm were produced. Here, the material of the element body was NiCuZn ferrite, and the thickness of the element body sandwiched between the internal electrode layers was 10 μm. The internal electrode was made of Ag and the thickness was 5 μm.

Next, 70% by mass of silver powder, 7% by mass of glass powder, and the remainder is a binder and solvent base electrode paste such that the internal electrode of the laminate is exposed to a thickness of 6 μm after drying. It was applied to. The composition of the glass powder was 68% by mass of Bi ₂ O ₃ , 9% by mass of B ₂ O ₃ , 8% by mass of ZnO, 5% by mass of SiO ₂ , 3% by mass of ZrO ₂ , and ₂ % by mass of Na ₂ O. The other components were 5% by mass. Hereinafter, this paste is abbreviated as paste H. On top of this, 70% by mass of silver powder, 7% by mass of glass powder, and the remainder was applied with a binder and solvent as a base electrode paste so that the thickness after drying was 24 μm. The composition of the glass powder _Bi 2 _{O 3} is 34 _wt%, B 2 _{O 3} is 21 wt%, ZnO is 19 mass%, SiO ₂ is 9 wt%, ZrO ₂ is 8 mass%, Na ₂ O 4% by weight The other components were 5% by mass. Hereinafter, this paste is abbreviated as “paste L”. Furthermore, paste H was applied to the same thickness thereon and baked at a sintering temperature of 680 ° C. for 10 minutes. The thickness of the base electrode after firing was 30 μm. Next, 100 chips after firing were arbitrarily extracted, and Ni plating metal layer was formed on the base electrode by 2 μm by electric barrel plating, and further Sn plating metal layer was formed by 4 μm thereon. The Ni plating solution was a Watt bath having a pH of 4.5 and a solution temperature of 40 ° C., and the Sn plating solution was a neutral bath having a pH of 6.

  Ten chips after terminal plating are arbitrarily extracted and cross-section polished, and a surface analysis of the composition of Bi and Ag is performed in the region of 250 μm width in the center, and the distribution in the depth direction of the amount of bismuth oxide in the glass component is determined. evaluated. The results of averaging 10 chips are shown in FIG. Next, the average value of the amount of bismuth oxide 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 laminated body is the content of the surface region on the laminated body side, the plated metal layer The average value of 10 to 20 μm corresponding to the region from 1/6 to 5/6 of the thickness of the base electrode from the interface with the intermediate electrode is the content of the intermediate region, and the thickness of the base electrode from the interface with the plated metal layer The average value from 25 to 30 μm corresponding to a region having a depth of 1/6 of the thickness was taken as the content of the surface region on the plated metal layer side. Moreover, the one where the content of the surface region on the plated metal layer side and the content of the surface region on the laminate side is the surface region content was compared with the content of the intermediate region. The results are shown in Table 1.

  Next, the inductance and DC resistance at 1 MHz of 100 chips were measured. And the thermal shock test which applies the thermal shock of -55 degreeC to 155 degreeC 2000 cycles and 3000 cycles was done, and the inductance and DC resistance after a test were measured. A chip in which at least one of the inductance and DC resistance before and after the test changed by 20% or more was judged as defective. The results are shown in Table 1. The number of defects after 3000 cycles of thermal shock test is the total number including defective chips after 2000 cycles. There was no chip judged to be defective in Example 1.

[Example 2]
A chip was prepared in the same manner as in Example 1 except that the composition of the glass powder of paste H was changed to 61.5% by mass of Bi ₂ O ₃ and other compositions were adjusted without changing the ratio of each component. And evaluated. The results are shown in Table 1.

Example 3
A chip was prepared in the same manner as in Example 1 except that the composition of the glass powder of paste H was changed to 55.5% by mass of Bi ₂ O ₃ and the other compositions were adjusted without changing the ratio of each component. And evaluated. The results are shown in Table 1.

Example 4
A chip was prepared in the same manner as in Example 1 except that the composition of the glass powder of paste H was changed to 49.0% by mass of Bi ₂ O ₃ and the other compositions were adjusted without changing the ratio of each component. And evaluated. The results are shown in Table 1.

Example 5
A chip was prepared in the same manner as in Example 1 except that Bi ₂ O ₃ was changed to 42.0% by mass with respect to the composition of the glass powder of paste H, and other compositions were adjusted without changing the ratio of each component. And evaluated. The results are shown in Table 1.

Example 6
A chip was prepared in the same manner as in Example 1 except that the composition of the paste H glass powder was changed to 37.0% by weight of Bi ₂ O ₃ and the other compositions were adjusted without changing the ratio of each component. And evaluated. The results are shown in Table 1.

Example 7
A chip was prepared in the same manner as in Example 1 except that Bi ₂ O ₃ was changed to 35.0% by mass with respect to the composition of the glass powder of paste H, and other compositions were adjusted without changing the ratio of each component. And evaluated. The results are shown in Table 1.

  From Examples 1 to 7, it can be seen that when the content of bismuth oxide in the surface region is larger than the content of the intermediate region, no defect occurs in the thermal shock test of 2000 cycles. In particular, it can be seen that when the content of bismuth oxide in the surface region is 20% or more higher than the content in the intermediate region, no defect occurs even in the 3000-cycle thermal shock test.

Example 8
The same laminate as Example 1 was prepared, and on the surface where the internal electrodes were exposed, paste H was 6 μm, paste L was 9 μm, paste H was 6 μm, paste L was 9 μm, and paste H was 6 μm in order from the laminate side. The thickness of each was applied. The firing conditions were the same as in the example at 680 ° C. for 10 minutes, because 9 out of 100 defects occurred, and the firing temperature was lowered to 660 ° C. for 10 minutes. Otherwise, a chip was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. The results are shown in Table 1. Moreover, the result of having measured the depth direction distribution of the amount of bismuth oxide in a glass component in EPMA is shown in FIG. Even if there is a region with a lot of bismuth oxide in the middle region,
It can be seen that when the content of bismuth oxide in the surface region is 20% or more higher than the content in the intermediate region, no defect occurs even in the 3000-cycle thermal shock test.

Example 9
In the laminated body of Example 1, the material of the element body was a varistor mainly composed of ZnO, and the material of the internal electrode was Pd. And after chip | tip preparation, the glass layer which has the composition of the same glass powder as the paste H was formed by the thickness of 3 micrometers on the surface which the laminated body has exposed. Others were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1. Even when the chemical resistance of the element body is poor, a glass layer is formed on the exposed surface of the laminate, and if the content of bismuth oxide in the surface region of the base electrode is more than 20% more than the content of the intermediate region, 3000 cycles It can be seen that no defect occurs even in the thermal shock test.

[Comparative Example 1]
A chip was prepared and evaluated in the same manner as in Example 1 except that the base electrode was made with a paste L alone to a thickness of 30 μm. The results are shown in Table 2, and defects occurred after the thermal shock test. The cause of all defects was excessive DC resistance. When the cross section of the interface between the defective chip laminate and the base electrode was observed by FIB, a crack was generated at the interface between the base electrode and the laminate.

[Comparative Example 2]
A chip was prepared and evaluated in the same manner as in Example 1 except that the paste on the plated metal layer side was changed to paste L. The results are shown in Table 2, and defects occurred after the thermal shock test. The cause of all defects was excessive DC resistance. When the cross section of the interface between the defective chip laminate and the base electrode was observed by FIB, a crack was generated at the interface between the base electrode and the laminate.

[Comparative Example 3]
A chip was prepared and evaluated in the same manner as in Example 1 except that the paste on the laminate side was changed to paste L. The results are shown in Table 2, and defects occurred after the heat cycle test. The cause of all defects was excessive DC resistance. When the cross section of the interface between the defective chip laminate and the base electrode was observed by FIB, a crack was generated at the interface between the base electrode and the laminate.

[Comparative Example 4]
A chip was prepared and evaluated in the same manner as in Example 1 except that the paste corresponding to the intermediate region, to which the paste L was applied in Example 1, was replaced with the paste H. The results are shown in Table 2. In Comparative Example 4, the firing condition of the base electrode was set at 680 ° C. for 10 minutes as in Example 1. As a result, 32 out of 100 defects occurred during firing of the base electrode, and the firing temperature was 640 ° C. (10 minutes). The results are shown in Table 2, and defects occurred after the thermal shock test. The cause of all defects was excessive DC resistance. When the cross section of the interface between the defective chip laminate and the base electrode was observed by FIB, a crack was generated at the interface between the base electrode and the laminate.

  From Comparative Examples 1 to 4, it can be seen that when the content of bismuth oxide in the surface region is less than the content of the intermediate region, a defect occurs in the thermal shock test of 2000 cycles.

  As described above, the ceramic multilayer electronic component according to the present invention is useful for improving the thermal shock resistance.

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 ... Ni plating metal layer 6b ... Sn plating metal layer 7 ... Terminal electrode 7a ... Main surface of terminal electrode 7b ... Terminal electrode Side surface 8 ... Boundary line 9 ... Measurement area 10 ... Glass layer 11 ... Unit structure

Claims (3)

  It has 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, and the glass component of the surface region is A ceramic laminated electronic component comprising bismuth oxide and having a bismuth oxide content in a glass component in a surface region greater than a bismuth oxide content in a glass component in the intermediate region.   2. The ceramic multilayer electronic component according to claim 1, wherein the content of bismuth oxide in the glass component in the surface region is 20% by mass or more than the content of bismuth oxide in the glass component in the intermediate region.   3. The ceramic multilayer electronic component according to claim 1, wherein a glass layer is formed on an exposed surface of the element body.

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