JP4730559B2 - Electronic component and manufacturing method thereof - Google Patents

Description

  The present invention relates to an electronic component (CR composite component) in which a resistor layer is formed on an electrode portion of a multilayer ceramic capacitor, and further relates to a manufacturing method thereof.

  For example, in a secondary side circuit such as a DC-DC converter or a switching power supply, the equivalent series resistance (ESR) of the smoothing circuit greatly affects the phase characteristics of the feedback loop, and a problem may occur particularly when the ESR becomes extremely low. . That is, when a multilayer ceramic capacitor having a low ESR is used as the smoothing capacitor, the secondary side smoothing circuit is equivalently composed of only the L and C components, and the phase components existing in the circuit are only ± 90 ° and 0 °. Thus, there is no phase margin and oscillation easily occurs. A similar phenomenon appears as an oscillation phenomenon when the load fluctuates even in a power supply circuit using a three-terminal regulator.

  Or, in the CR circuit or the like, the problem is that the impedance varies depending on the frequency and the voltage fluctuates as the current decreases. For example, with recent dual-core CPUs and the like, current fluctuations occur with a period of several kHz to 100 MHz, and voltage fluctuations occur due to the impedance of the power supply. Therefore, in order to cope with these disadvantages, electronic components such as CR composite components have been proposed in which a resistance layer is formed on the base electrode of the multilayer ceramic capacitor and this is functioned as a resistor so that ESR is increased to some extent. (See, for example, Patent Document 1).

In Patent Document 1, a multilayer ceramic capacitor element body in which an internal electrode is formed, a base electrode layer provided on the end face where the internal electrode of the capacitor element body is exposed so as to be electrically connected to the internal electrode, A CR element is disclosed that includes a resistance layer provided on a base electrode layer and a terminal electrode layer provided on the resistance layer and not in contact with the base electrode layer. By using such a CR element and appropriately controlling the resistance value of the resistance layer, voltage fluctuation can be suppressed regardless of the frequency.
Japanese Patent Laid-Open No. 10-303066

  In the above-mentioned CR composite parts, it is required to reduce the manufacturing cost, and it is considered to form the internal electrodes of the multilayer ceramic capacitor with an inexpensive base metal (for example, Ni). In this case, a conductive material containing a noble metal such as Pd, Au, or Pt, such as an AgPd alloy, is used for the base electrode layer, and this is fired in a non-oxidizing atmosphere, so that Ni contained in the internal electrode and the base electrode layer are included. Part of the noble metal such as Pd is replaced, and the internal electrode and the base electrode layer are in a good connection state. Further, if the firing is performed in a non-oxidizing atmosphere such as a reducing atmosphere, the internal electrode made of a base metal is not oxidized.

  However, when such a configuration is adopted, Ni substituted with a noble metal such as Pd may diffuse from the base electrode layer to the resistor layer formed thereon, which may adversely affect the characteristics. Ni diffused in the resistor layer is oxidized to nickel oxide. Nickel oxide is an insulator, and as the Ni diffuses, the ratio of the insulator in the resistor layer increases to increase the resistance value. Nickel oxide also has the advantage of improving the plating solution resistance of the resistor layer. However, in order to properly control the resistance value of the resistor layer and appropriately control this, it is necessary to apply the Ni to the resistor layer. It is necessary to suppress diffusion.

  The present invention has been proposed in view of the above-described conventional situation, and can prevent diffusion of Ni contained in the internal electrode of the multilayer ceramic capacitor into the resistor layer, thereby causing resistance value fluctuation (ESR). It is an object of the present invention to provide an electronic component capable of suppressing (variation) and a manufacturing method thereof.

  In order to achieve the above object, the electronic component according to the first invention of the present application is connected to the internal electrode of the multilayer ceramic capacitor to form a base electrode, and the resistor layer and the external electrode are formed on the base electrode. In the formed electronic component, the internal electrode of the multilayer ceramic capacitor contains Ni, the base electrode is composed of a plurality of conductor layers, and the conductor layer in contact with the internal electrodes is made of Pd, Au, and Pt. It contains at least one kind selected and includes an Ag layer as a conductor layer laminated thereon.

  In addition, a manufacturing method for manufacturing the electronic component having the above configuration includes a first method that includes at least one selected from Pd, Au, and Pt in contact with the internal electrode of the multilayer ceramic capacitor having the internal electrode containing Ni. Forming a conductor layer and firing in a non-oxidizing atmosphere; forming an Ag layer on the first conductor layer as a second conductor layer and firing in a non-oxidizing atmosphere; and a resistor layer; Forming an external electrode.

  In the electronic component of the present invention, since Ni, which is a base metal, is used for the internal electrode of the multilayer ceramic capacitor, the cost is greatly reduced compared to the case where a noble metal electrode is used. Further, since the base electrode layer (first conductor layer) in contact with the internal electrode contains at least one selected from Pd, Au, and Pt, a part of the base electrode layer is replaced with Ni of the internal electrode. And the base electrode layer (first conductor layer) are securely connected.

  However, if the base electrode layer is only the first conductor layer, Ni diffused in the first conductor layer by the substitution further diffuses to the resistor layer, which adversely affects its characteristics. Therefore, in the electronic component of the present invention, the base electrode layer has a multilayer structure, and the Ag layer is interposed as the second conductor layer between the first conductor layer and the resistor layer. Ag constituting the Ag layer is not substituted or compatible with Ni. Therefore, the Ag layer functions as a diffusion preventing layer for preventing the diffusion of Ni, and the Ni diffusion to the resistor layer is prevented by interposing the Ag layer.

  On the other hand, the electronic component of the second invention of the present application is an electronic component in which a ground electrode is formed by being connected to the internal electrode of the multilayer ceramic capacitor, and a resistor layer and an external electrode are formed on the ground electrode. The multilayer ceramic capacitor includes an internal electrode containing Ni, the base electrode is composed of a plurality of conductor layers, and at least one of the conductor layers in contact with the internal electrode is selected from Pd, Au, and Pt. And an oxide of Ni exists in the vicinity of at least one of the interfaces between the conductor layers.

  In addition, a manufacturing method for manufacturing the electronic component having the above configuration includes a first method that includes at least one selected from Pd, Au, and Pt in contact with the internal electrode of the multilayer ceramic capacitor having the internal electrode containing Ni. Forming a conductor layer and firing in a non-oxidizing atmosphere; forming a second conductor layer containing at least one selected from Ag, Pd, Au, and Pt on the first conductor layer; And a step of forming a resistor layer and an external electrode.

  Also in the electronic component of the present invention, since Ni, which is a base metal, is used for the internal electrode of the multilayer ceramic capacitor, the cost is greatly reduced compared to the case where a noble metal electrode is used, and the base electrode layer (in contact with the internal electrode) Since the first conductor layer) contains at least one selected from Pd, Au, and Pt, a part of the first conductor layer is replaced with Ni of the internal electrode, and the internal electrode and the base electrode layer (first conductor layer) It is the same that and are securely connected.

  In the case of the present invention, the second conductor layer formed on the first conductor layer is fired in an atmosphere containing oxygen so that Ni diffused in the first conductor layer does not diffuse into the resistor layer. I have to. When oxygen is baked in an atmosphere, Ni diffused in the first conductor layer is oxidized and becomes an oxide. Ni in the metal state can diffuse into the second conductor layer containing at least one selected from Ag, Pd, Au, and Pt, but the oxide of Ni cannot diffuse into the second conductor layer. . As a result, the Ni oxide stops at the interface between the second conductor layer and the underlying conductor layer (for example, the first conductor layer), and the Ni layer is formed in the resistor layer formed on the second conductor layer. The oxide does not diffuse.

  According to the present invention, it is possible to prevent the diffusion of Ni contained in the internal electrode of the multilayer ceramic capacitor to the resistor layer while ensuring the electrical connection between the internal electrode of the multilayer ceramic capacitor and the base electrode layer. It is possible to suppress resistance value fluctuation (ESR fluctuation) due to this.

  Hereinafter, an electronic component (CR composite component) to which the present invention is applied and a manufacturing method thereof will be described in detail with reference to the drawings.

(First embodiment)
The present embodiment is an example in which an Ag layer is formed as the second conductor layer constituting the base electrode layer, thereby preventing Ni from diffusing into the resistor layer.

  FIG. 1 shows an example of a CR composite part. The CR composite component 1 includes a multilayer ceramic capacitor 2 that is a ceramic multilayer body as an element body, and a base electrode layer 3, a resistor layer 4, and an external electrode layer 5 are formed on the side surfaces thereof.

  In the multilayer ceramic capacitor 2, a plurality of dielectric ceramic layers 21 and internal electrode layers 22 are alternately stacked. The internal electrode layer 22 is laminated so that the side end faces are alternately exposed on the two opposing end faces of the element body, and a pair of base electrodes 3 are provided on both side ends of the element body. It is formed so as to be electrically connected. The shape of the element body is not particularly limited, but is usually a rectangular parallelepiped shape. The dimensions are not particularly limited, and may be set to appropriate dimensions according to the application.

The dielectric ceramic layer 21 constituting the multilayer ceramic capacitor 2 is made of a dielectric ceramic composition, and is formed by sintering powder (ceramic powder) of the dielectric ceramic composition. The dielectric ceramic composition includes, for example, a composition formula ABO ₃ (wherein the A site is composed of at least one element selected from Sr, Ca and Ba. The B site is at least selected from Ti and Zr). And the like containing a dielectric oxide having a perovskite crystal structure represented by the following formula: Among the dielectric oxides, barium titanate or the like in which the A site element is Ba and the B site element is Ti is preferable.

  The dielectric ceramic composition may contain various subcomponents in addition to the main component. Subcomponents are selected from oxides of Sr, Zr, Y, Gd, Tb, Dy, V, Mo, Zn, Cd, Ti, Sn, W, Ba, Ca, Mn, Mg, Cr, Si and P. At least one is exemplified. By adding the subcomponent, for example, low temperature firing is possible without deteriorating the dielectric characteristics of the main component. Further, the occurrence of defects when the dielectric ceramic layer 21 is thinned is reduced, and the life can be extended.

  Various conditions such as the number and thickness of the dielectric ceramic layers 21 may be appropriately determined according to required characteristics and applications. The thickness of the dielectric ceramic layer 21 is about 1 μm to 50 μm and is usually about 5 μm to 20 μm, but may be 5 μm or less. For example, from the viewpoint of reducing the size and capacity of the multilayer ceramic capacitor 2, the thickness of the dielectric ceramic layer 21 is preferably 3 μm or less. The number of laminated dielectric ceramic layers 2 is about 2 to 300, but is preferably 150 or more in consideration of performance (capacity) and the like.

  For the internal electrode layer 22, a noble metal such as Ag or Pd is usually used, but in this embodiment, a conductive material containing Ni as a base metal (for example, Ni or Ni alloy) is used. By using a conductive material containing Ni, the manufacturing cost can be significantly reduced as compared with the case where noble metal is used. In addition, the thickness of the internal electrode layer 22 may be appropriately determined according to the use and the like, and is, for example, about 0.5 μm to 5 μm, preferably 1.5 μm or less.

  The base electrode layer 3 formed on the side surface of the multilayer ceramic capacitor 2 is electrically connected to the internal electrode layer 22 of the multilayer ceramic capacitor 2 and functions as an extraction electrode for the internal electrode layer 22. For the formation of the base electrode layer 3, an electrode forming composition containing a conductive metal material and a glass component is used. In the present embodiment, the base electrode layer 3 is used as the first conductor layer 3a and the second conductor layer 3b. It has a two-layer structure. In addition, the number of the conductor layers which comprise the base electrode layer 3 is not restricted to two layers, For example, three or more layers may be sufficient. However, considering the function, production cost, etc., it is preferable to have two layers which are the minimum configuration.

  Here, it is necessary that the first conductor layer 3a, which is the lower layer of the base electrode layer 3, be electrically connected to the internal electrode layer 22 of the multilayer ceramic capacitor 2 reliably. Therefore, the first conductor layer 3a needs to contain at least one selected from Pd, Au, and Pt. For example, an AgPd alloy or the like can be used. If any of Pd, Au, and Pt is included in the first conductor layer 3a, when the first conductor layer 3a is formed on the internal electrode layer 22, a part thereof is included in the internal electrode layer 22. It is replaced with Ni, and electrical connection is ensured.

  However, if the Ni diffused in the first conductor layer 3a by the substitution is diffused to the resistor layer 4, the characteristics of the resistor layer 4 may vary. Therefore, the second conductor layer 3b is overlaid on the first conductor layer 3a, and the second conductor layer 3b is interposed between the first conductor layer 3a and the resistor layer 4, so that the resistance of the Ni is increased. Prevents diffusion into the body layer 4. Therefore, the second conductor layer 3b needs to be formed of a metal having low compatibility with Ni. Here, the Ag layer is the second conductor layer 3b. When the second conductor layer 3b contains Pd, Au, or Pt, Ni diffuses into the second conductor layer 3b, and cannot function as a diffusion preventing layer. By making the 2nd conductor layer 3b into an Ag layer, the function as a diffusion prevention layer is exhibited with respect to Ni.

  The Ag layer formed as the second conductor layer 3b is ideally formed only from Ag, but is not limited thereto. For example, as long as it is mainly composed of Ag, it may contain other metals (a metal having low compatibility with Ni), and also excludes other components as unavoidable impurities. Is not to be done.

  When the base electrode layer 3 is composed of three or more conductor layers, a plurality of (two or more) conductor layers are formed on the first conductor layer 3a. In this case, Any one layer on the first conductor layer 3a may be an Ag layer (second conductor layer 3b). Of course, the plurality of layers on the first conductor layer 3a may be Ag layers.

  A resistor layer 4 is formed on the base electrode layer 3 composed of the first conductor layer 3a and the second conductor layer 3b. As a result, the capacitor C (multilayer ceramic capacitor 2) and the resistor are formed. R (resistor layer 4) is connected in series to provide a function as a CR composite part.

The resistance material used for the resistor layer 4 is arbitrary, and for example, it is preferable to use a mixture (so-called metal glaze) of a glass component and a Ru-based oxide which is a conductive material. Examples of the Ru-based oxide include CaRuO ₃ , SrRuO ₃ , BaRuO ₃ , RuO ₂ , Bi ₂ Ru ₂ O _{7 and the} like. The ratio between the glass component and the conductive material may be set according to a desired resistance value. When the ratio of the glass component increases, the resistance value increases, and when the ratio of the glass component decreases, the resistance value decreases.

  On the resistor layer 4, the external electrode layer 5 is formed as the outermost electrode layer. The external electrode layer 5 functions as an external terminal of the CR composite component 1 and has a small resistance value and good solder wettability in consideration of lead wire attachment and soldering during mounting. Is preferred. Therefore, it is preferable that at least a part (surface portion) of the external electrode layer 5 is formed of a plating film. For example, an Ag paste or the like is fired to form the sintered metal layer 5a, and further plated with Ni, Sn, tin-lead alloy solder or the like to form a plated film 5b. The sintered metal layer 5a and the plated film 5b May be used as the external electrode layer 5. As for the plating film 5b, for example, the inner side can be a Ni plating film and the outer side can be a tin-lead alloy solder plating film. The thickness of the plating film 5b is, for example, about 0.1 μm to 20 μm.

  In the electronic component (CR composite component) of the present embodiment having the above-described configuration, the internal electrode layer 22 of the multilayer ceramic capacitor 2 is formed of Ni, so that compared to the case where the internal electrode layer 22 is formed of noble metal. Manufacturing costs can be significantly reduced. In addition, since the first conductor layer 3a in contact with the internal electrode layer 22 contains Pd, Au, or Pt, these metals and Ni constituting the internal electrode layer 22 are partly replaced, and good electrical connection is achieved. A state is realized. Furthermore, since the second conductor layer 3b is formed on the first conductor layer 3a and prevents the diffusion of Ni into the resistor layer 4, the resistance value fluctuation (ESR fluctuation) can be suppressed. It is.

  Next, a method for forming the above-described CR composite component 1 manufacturing method will be described. In the CR composite component 1 in which the internal electrode layer 22 is formed of Ni as a base metal, in order to form the base electrode layer 3 on the multilayer ceramic capacitor 2, first, as shown in FIG. In order to form the layer 3a, the first conductor precursor layer 11 is formed in contact with the internal electrode layer 22 on the side surface of the multilayer ceramic capacitor 2 which is a ceramic multilayer body. The first conductor precursor layer 11 is made of a conductive metal material (containing at least one selected from Pd, Au, Pt) and a conductive paste (eg, AgPd paste) containing a glass component, such as dipping or printing. Is applied to the end face of the multilayer ceramic capacitor 2 using

  Next, the first conductor precursor layer 11 is fired (reduced firing) in a non-oxidizing atmosphere to form the first conductor layer 3a. The first conductor precursor layer 11 contains an organic substance such as an organic vehicle. Therefore, at the time of the reduction firing, first, a binder removal step of decomposing and removing organic substances contained in the first conductor layer 11 is performed. The binder removal step may be performed in the atmosphere, for example, at a temperature of about 400 ° C.

After the binder removal step, the first conductor precursor layer 11 is reduced in a reduction treatment step. The reduction treatment is performed by heating to a predetermined reduction temperature in an atmosphere containing a reducing gas such as hydrogen. In this reduction treatment step, when hydrogen reduction treatment is performed, the sample is set in a reaction furnace capable of atmospheric firing at room temperature and sealed. The atmosphere in the furnace is replaced with a hydrogen-containing atmosphere, for example, 95% N ₂ -5% H ₂ mixed gas (N ₂ -5% H ₂ ), the temperature is raised to a predetermined temperature, and after a predetermined time, the temperature is lowered. The hydrogen concentration may be set to about 0.1% to 10%. Although the internal electrode layer 22 formed of the base metal is oxidized by the previous binder removal step, it is reduced by performing this reduction treatment step, and the original function of the internal electrode layer 22 is restored.

  In addition, it is preferable that the reduction temperature in the said reduction process process shall be 250 to 500 degreeC. If the reduction temperature is less than 250 ° C., the reduction of the internal electrode layer 22 may not proceed sufficiently. On the contrary, if the reduction temperature exceeds 500 ° C., the dielectric ceramic layer 21 constituting the multilayer ceramic capacitor 2 may be reduced and the characteristics may be deteriorated.

  After the reduction treatment step, a baking step is performed. This baking step is a step for baking the first conductor precursor layer 11 on the multilayer ceramic capacitor 2 to form the first conductor layer 3a. The baking process is performed in an inert gas atmosphere (non-oxidizing atmosphere) such as a nitrogen atmosphere or an Ar gas atmosphere, or in a reducing atmosphere containing hydrogen or the like. The temperature may be set to a temperature necessary for baking, and is preferably set to, for example, 850 ° C. or higher in order to make the formed first conductor layer 3a dense.

  Next, as shown in FIG. 2B, the second conductor precursor layer 12 for forming the second conductor layer 3b is formed on the first conductor layer 3a. The second conductor precursor layer 12 is formed by printing or applying an Ag paste.

  Similar to the first conductor precursor layer 11, the second conductor precursor layer 12 is subjected to binder removal, reduction treatment, and baking to form a second conductor layer 3b. Baking is performed in an inert gas atmosphere (non-oxidizing atmosphere), such as a nitrogen atmosphere or an Ar gas atmosphere, or in a reducing atmosphere, so-called reduction firing.

  The firing process for forming the base electrode layer 3 includes the above-described firing process for forming the first conductor layer 3a and the firing process for forming the second conductor layer 3b. The body layer 4 and the external electrode layer 5 are formed.

  In the resistor precursor layer forming step, the resistor paste is printed to form the resistor precursor layer 13, and the resistor layer 4 is formed by firing in the firing step. As the resistor paste, a resistor paste including a conductive material (Ru-based oxide or the like) and a glass component is used, and a glass component having the above-described composition is used as the glass component. For example, when a metal glaze containing a Ru-based oxide is used as a resistance material, firing is performed in the atmosphere at a temperature of about 850 ° C. in order to prevent reduction of the Ru oxide. Thereby, the resistor layer 4 is baked and formed on the base electrode layer 3. At this time, since the base electrode layer 3 formed by the reduction firing process functions as an oxygen permeation preventive film, oxygen in the atmosphere does not enter and oxidize the internal electrode layer 22.

  After the formation of the resistor layer 4, a conductive paste such as an Ag paste is applied by a technique such as dipping in the external electrode precursor layer forming step, and the external electrode layer 5 is formed by baking this in the baking step. The baking process may be performed at a temperature of about 750 ° C. in the atmosphere, for example. A plating film is formed outside the external electrode layer 5. The plating film is formed by wet plating, for example.

  According to the above manufacturing method, since the second conductor layer 3b is formed of Ag, the function of preventing diffusion of Ni into the resistor layer 4 is achieved, and the resistance value fluctuation of the resistor layer 4 is prevented. In the case of this embodiment, since the second conductor layer 3b is also formed by reduction firing, for example, when the second conductor precursor layer 12 contains Pd, Au, or Pt, the first conductor layer 3a The diffused Ni also diffuses into the second conductor layer 3 b and further diffuses to the resistor layer 4. On the other hand, the second conductor precursor layer 12 is formed of an Ag paste, and the second conductor layer 3b is an Ag layer. Ni contained in the internal electrode layer 22 or the first conductor layer 3a does not diffuse into the second conductor layer 3b or the resistor layer 4 during firing.

(Second Embodiment)
In the present embodiment, the base electrode layer 3 is composed of two or more conductor layers, and Ni is oxidized at the interface between these conductor layers to prevent Ni from diffusing into the resistor layer 4. The basic configuration of the CR composite component 1 is the same as that of the first embodiment, and the base electrode layer 2 is also composed of a plurality of conductor layers. The diffusion into the resistor layer 4 is prevented by oxidizing Ni diffused in the first conductor layer 3a.

  That is, the first conductor layer 3a of the base electrode layer 3 is formed of a conductive material containing Pd, Au, or Pt, like the CR composite component of the first embodiment. Therefore, Ni contained in the internal electrode layer 22 of the multilayer ceramic capacitor 2 diffuses into the first conductor layer 3a. In the case of this embodiment, for example, the second conductor layer 3a has the second conductor layer 3a on the second conductor layer 3a. When the conductor layer 3b is formed, firing is performed in an atmosphere containing oxygen. Thereby, Ni contained in the first conductor layer 3a becomes an oxide (nickel oxide) and precipitates in the vicinity of the interface between the first conductor layer 3a and the second conductor layer 3b. Ni that has become an oxide does not diffuse into the second conductor layer 3b, which is a metal layer.

  In the present embodiment, the precipitation of the Ni oxide is not limited to the interface between the first conductor layer 3a and the second conductor layer 3b. For example, when the base electrode layer 3 is composed of three or more conductor layers, it may be near the interface between the second conductor layer and the third conductor layer, or even at the upper interface. Good. It is optional if it is below the top layer. The presence of the Ni oxide can be confirmed by various elemental analysis.

  In the configuration described above, the second and subsequent conductor layers are not limited to the Ag layer, unlike the case of the first embodiment. This is because the Ni oxide cannot diffuse into the conductor layer containing Pd or the like. Therefore, the second and subsequent conductor layers such as the second conductor layer 3b may be formed of a conductive material containing at least one selected from Ag, Pd, Au, and Pt (for example, an AgPd alloy). Of course, an Ag layer may be used.

  Also in the electronic component (CR composite component) of the present embodiment having the above configuration, since the internal electrode layer 22 of the multilayer ceramic capacitor 2 is formed of Ni, compared with the case where the internal electrode layer 22 is formed of noble metal. Manufacturing costs can be significantly reduced. In addition, since the first conductor layer 3a in contact with the internal electrode layer 22 contains Pd, Au, or Pt, these metals and Ni constituting the internal electrode layer 22 are partly replaced, and good electrical connection is achieved. A state is realized. Furthermore, since the second conductor layer 3b is formed on the first conductor layer 3a and Ni is used as an oxide at this time, diffusion of Ni into the resistor layer 4 is prevented, so that the resistance Value fluctuation (ESR fluctuation) can be suppressed.

  Next, a method for manufacturing the CR composite component of this embodiment will be described. In the manufacture of the CR composite component of the present embodiment, the processes up to the formation of the first conductor layer 3a are the same as those of the first embodiment. That is, also in this embodiment, the first conductor precursor layer is formed in contact with the internal electrode layer on the side surface of the multilayer ceramic capacitor which is a ceramic multilayer body. The first conductor precursor layer is formed by a conductive paste (for example, AgPd paste) containing a conductive material containing at least one selected from Pd, Au, and Pt and a glass component. The first conductor precursor layer is fired (reduction firing) in a non-oxidizing atmosphere.

  Next, a second conductor precursor layer is formed. The second conductor precursor layer is a conductive paste containing a conductive material containing at least one selected from Ag, Pd, Au, Pt and a glass component (for example, an AgPd paste or the like). ). The second conductor precursor layer is fired to form the second conductor layer 3b. The second conductor precursor layer is fired in an atmosphere containing oxygen. Therefore, for example, after performing the same binder removal as in the case of the first conductor precursor layer, no reduction treatment is performed, and baking is also performed in an atmosphere containing oxygen (for example, in the air).

  By baking the second conductor layer 3b in an oxygen-containing atmosphere, Ni diffused in the first conductor layer 3a is oxidized, and Ni in the second conductor layer 3b and further on the resistor layer 4 is oxidized. Diffusion is prevented. In addition, since the second conductor layer 3b is baked in a state where the dense first conductor layer 3a is already formed, the internal electrode layer 22 of the multilayer ceramic capacitor 2 can be formed even if baking is performed in an atmosphere containing oxygen. It is not oxidized.

  After the formation of the second conductor layer 3b, the resistor layer 4 and the external electrode layer 5 are formed, and the formation method thereof is the same as that of the first embodiment.

  Hereinafter, specific examples of the present invention will be described based on experimental results.

(Example 1)
A conductive paste using AgPd alloy (containing 30% by mass of Pd) as a conductive metal material is printed on the base electrode forming portion of a chip capacitor (capacitance 10 μF ± 20%) having a Ni internal electrode, which is a base metal, and removed at 350 ° C. in the atmosphere. Binder was done. Further, a hydrogen reduction treatment was performed at 320 ° C., and baking was performed at 950 ° C. in nitrogen to form a first conductor layer. Next, an Ag paste layer is formed on the first conductor layer, and the second conductor layer (Ag layer) is formed by performing binder removal, hydrogen reduction treatment, and baking in nitrogen as in the first conductor layer. Formed.

After forming a base electrode layer composed of the first conductor layer and the second conductor layer, a resistor paste (Ru-based oxide metal glaze paste) is printed on the base electrode layer and baked at 850 ° C. in the atmosphere. Thus, a resistor layer was formed. CaRuO ₃ was used as the conductive material of the resistor paste, and the ratio of the glass component to the conductive material was 20:80 (volume ratio). Further, an Ag paste was applied and baked on the resistor layer to form an Ag sintered layer, and an Ni plated film and an Sn plated film were formed on the Ag sintered layer by a wet plating method.

  The design value of the sheet resistance of the resistor layer was set to 100Ω / □, 1 kΩ, and 10 kΩ, and ESR was actually measured. As a result, when the design value of the sheet resistance of the resistor layer is 100Ω / □, ESR = 16 mΩ (calculated value 10 mΩ), when 1 kΩ, ESR = 112 mΩ (calculated value 100 mΩ), when 10 kΩ, ESR = It was 1059 mΩ (calculated value 1000 mΩ), which was in good agreement with the calculated value. From this, it can be seen that in the CR composite component of this example, the resistance value fluctuation of the resistor layer is suppressed to a small value. It is considered that the formation of the Ag layer (second conductor layer) prevented the diffusion of Ni, and as a result, the resistance value fluctuation was suppressed.

  In addition, the measured value of the capacitance C of the CR composite part was 10 μF regardless of the design value of the sheet resistance of the resistor layer. From this, it can be seen that the internal electrode layer and the base electrode layer are not oxidized and the function as an electrode is maintained.

(Example 2)
As in Example 1 above, a conductive paste using an AgPd alloy (containing 30 mass% Pd) as a conductive metal material is printed on a base electrode forming portion of a chip capacitor (capacitance 10 μF ± 20%) having a Ni internal electrode which is a base metal. The binder was removed at 350 ° C. in the atmosphere. Further, a hydrogen reduction treatment was performed at 320 ° C., and baking was performed at 950 ° C. in nitrogen to form a first conductor layer. Next, an AgPd paste layer was formed on the first conductor layer, the binder was removed in the atmosphere, and baking was performed in the atmosphere to form a second conductor layer (AgPd layer). Thereafter, a resistor layer and an external electrode layer (Ag sintered layer, Ni plated film, and Sn plated film) were formed, and these forming methods are the same as those in Example 1 above.

  As in Example 1, the design value of the sheet resistance of the resistor layer was set to 100Ω / □, 1 kΩ, and 10 kΩ, and ESR was measured. As a result, when the design value of the sheet resistance of the resistor layer is 100Ω / □, ESR = 14 mΩ (calculated value 10 mΩ), 1 kΩ, ESR = 106 mΩ (calculated value 100 mΩ), 10 kΩ, ESR = It was 1059 mΩ (calculated value 1000 mΩ), which was in good agreement with the calculated value. Also in the CR composite part of this example, the resistance value fluctuation of the resistor layer is suppressed to be small. This is because Ni is converted into an oxide by forming the second conductor layer in an atmosphere containing oxygen, and resistance. This is thought to be the result of preventing diffusion to the body layer.

  In addition, the measured value of the capacitance C of the CR composite part was 10 μF regardless of the design value of the sheet resistance of the resistor layer. From this, it can be seen that the internal electrode layer and the base electrode layer are not oxidized and the function as an electrode is maintained.

(Comparative Example 1)
As in Example 1 above, a conductive paste using an AgPd alloy (containing 30 mass% Pd) as a conductive metal material is printed on a base electrode forming portion of a chip capacitor (capacitance 10 μF ± 20%) having a Ni internal electrode which is a base metal. The binder was removed at 350 ° C. in the atmosphere. Further, a hydrogen reduction treatment was performed at 320 ° C., and baking was performed at 950 ° C. in nitrogen to form a first conductor layer.

  Next, the resistor layer and the external electrode layer (Ag sintered layer, Ni plated film, and Sn plated film) were formed without forming the second conductor layer. These forming methods are the same as those in the first embodiment.

  As in Example 1, the design value of the sheet resistance of the resistor layer was set to 100Ω / □, 1 kΩ, and 10 kΩ, and ESR was measured. As a result, when the design value of the sheet resistance of the resistor layer is 100Ω / □, ESR = 87 mΩ (calculated value 10 mΩ), 1 kΩ, ESR = 378 mΩ (calculated value 100 mΩ), 10 kΩ, ESR = It was 5801 mΩ (calculated value 1000 mΩ), which was greatly different from the calculated value. This is considered to be because Ni contained in the internal electrode layer diffused to the resistor layer through the first conductor layer. Note that, regardless of the design value of the sheet resistance of the resistor layer, the measured value of the capacitance C of the CR composite component was 10 μF, and the internal electrode layer and the base electrode layer maintained their functions as electrodes.

(Comparative Example 2)
The first conductor is formed by forming an Ag paste layer on the base electrode forming portion of a chip capacitor (capacitance 10 μF ± 20%) having a Ni internal electrode, which is a base metal, and performing binder removal, hydrogen reduction treatment, and baking in nitrogen. A layer (Ag layer) was formed. Next, the resistor layer and the external electrode layer (Ag sintered layer, Ni plated film, and Sn plated film) were formed without forming the second conductor layer. These forming methods are the same as those in the first embodiment.

  Similarly to Example 1, the design value of the sheet resistance of the resistor layer was set to 100Ω / □, 1 kΩ, and 10 kΩ, and attempts were made to actually measure ESR, but measurement was impossible. Further, the capacity C could not be measured. This is because the Ni of the internal electrode layer does not diffuse into the first conductor layer because the first conductor layer is an Ag layer, and electrical connection between the internal electrode layer and the base electrode layer cannot be achieved. Conceivable. The same result was obtained when two Ag layers were formed.

(Comparative Example 3)
The first conductor layer (Ag layer) is formed by forming an Ag paste layer on the base electrode forming portion of the chip capacitor (capacitance 10 μF ± 20%) having the Ni internal electrode, which is a base metal, and performing binder removal and baking in the atmosphere. Formed. Next, the resistor layer and the external electrode layer (Ag sintered layer, Ni plated film, and Sn plated film) were formed without forming the second conductor layer. These forming methods are the same as those in the first embodiment.

  Similarly to Example 1, the design value of the sheet resistance of the resistor layer was set to 100Ω / □, 1 kΩ, and 10 kΩ, and attempts were made to actually measure ESR, but measurement was impossible. Further, the capacity C could not be measured. This is presumably because the first conductor layer was formed in an atmosphere containing oxygen, so that the internal electrode layer was oxidized and lost its function as an electrode.

It is a schematic sectional drawing which shows an example of CR composite component. It is a schematic sectional drawing which shows an example of the manufacturing process of CR composite component, (a) is a 1st conductor precursor formation process, (b) is a 2nd conductor precursor formation process, (c) is a resistor layer formation process, (D) shows an external electrode layer forming step.

Explanation of symbols

1 CR composite component, 2 multilayer ceramic capacitor, 3 ground electrode layer, 3a first conductor layer, 3b second conductor layer, 4 resistor layer, 5 external electrode layer, 21 dielectric ceramic layer, 22 internal electrode layer

Claims (4)

An electronic component in which a base electrode is formed by being connected to an internal electrode of a multilayer ceramic capacitor, and a resistor layer and an external electrode are formed on the base electrode,
The internal electrode of the multilayer ceramic capacitor contains Ni,
The base electrode is composed of a plurality of conductor layers, the conductor layer in contact with the internal electrode contains at least one selected from Pd, Au, and Pt, and an Ag layer as a conductor layer laminated thereon Electronic parts characterized by including. An electronic component in which a base electrode is formed by being connected to an internal electrode of a multilayer ceramic capacitor, and a resistor layer and an external electrode are formed on the base electrode,
The internal electrode of the multilayer ceramic capacitor contains Ni,
The base electrode is composed of a plurality of conductor layers, at least the conductor layer in contact with the internal electrode contains at least one selected from Pd, Au, and Pt, and at least one of the interfaces between the conductor layers An electronic component comprising Ni oxide in the vicinity of an interface. Forming a first conductor layer containing at least one selected from Pd, Au, and Pt in contact with the internal electrode of the multilayer ceramic capacitor having an internal electrode containing Ni, and firing in a non-oxidizing atmosphere;
Forming an Ag layer as a second conductor layer on the first conductor layer and firing in a non-oxidizing atmosphere;
And a step of forming a resistor layer and an external electrode. Forming a first conductor layer containing at least one selected from Pd, Au, and Pt in contact with the internal electrode of the multilayer ceramic capacitor having an internal electrode containing Ni, and firing in a non-oxidizing atmosphere;
Forming a second conductor layer containing at least one selected from Ag, Pd, Au, and Pt on the first conductor layer, and firing in an atmosphere containing oxygen;
And a step of forming a resistor layer and an external electrode.

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