JP2006216636A - Composite laminated electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite laminated electronic component in which a varistor element portion and an inductor element portion can be bonded and integrated surely without causing any crack, thickness of an intermediate bonding layer can be set as thin as possible, and the component can be made compact. <P>SOLUTION: The composite laminated electronic component comprises a varistor element portion (10), an inductor element portion (20), and an intermediate bonding layer (50) being interposed to bond both element portions. The intermediate bonding layer (50) is constituted by laying first through N-th layers (N is an integer of 2 or above) of bonding film having different compositions in layers wherein the total thickness is 240 μm or less, difference in linear expansion coefficient between the inductor element portion and the first bonding film touching it is within 1 (ppm/K), difference in linear expansion coefficient between adjacent bonding films constituting other N-1 bonding interfaces is within 2 (ppm/K), and difference in linear expansion coefficient between the varistor element portion and the N-th bonding film touching it is within 2 (ppm/K). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composite laminated type having a varistor element part having a varistor layer and an internal electrode, an inductor element part having a ferrite layer and an internal conductor, and a joining intermediate layer interposed for joining both blocks. Regarding electronic components, in particular, the two element parts can be reliably joined and integrated without generating cracks, and the thickness of the joining intermediate layer for joining can be set as thin as possible. The present invention relates to a composite laminated electronic component.

  In computer equipment etc., ferrite chips, capacitor chips, varistors, etc. are incorporated in the input / output part of the circuit board and in the middle of the circuit so that the equipment itself does not generate noise and also does not enter the equipment from the outside. Yes.

  However, if many parts such as a multilayer varistor, inductor (ferrite chip), capacitor chip, etc. are added to the circuit board, these parts occupy a large area of the board, resulting in an increase in mounting space. . In addition, an increase in the number of parts causes a problem of cost increase.

  In order to deal with such problems, attempts have been made to make a composite part by integrally sintering each element chip in a state where the element chips are joined to each other, thereby reducing the size of the part and reducing the mounting space.

In particular, as a prior art related to the integration of a varistor and an inductor (ferrite chip), which is difficult to be integrated and sintered, for example, in Japanese Patent Application Laid-Open No. 7-220906, layer peeling, delamination and cracks are suppressed. In order to provide a composite functional element, in the case where a semiconductor ceramic having varistor characteristics and a magnetic material ceramic are joined and integrally molded, Bi ₂ O ₃ and a glass composition are added to both the semiconductor ceramic and the magnetic material ceramic. Proposals have been made to add it. However, even in this proposal, cracks still tend to occur on the joint surface at the interface between the semiconductor ceramic and the magnetic ceramic, and it can be said that it is extremely difficult to obtain a joint force sufficient for commercialization.

  Japanese Patent Laid-Open No. 7-22210 discloses a case where a semiconductor ceramic having a varistor characteristic and a magnetic ceramic mainly composed of an Fe—Ni—Zn-based material are laminated and integrally formed. Proposals have been made to configure Bi to be added to both porcelains. However, in this proposal as well, as in the above prior art, cracks are likely to occur at the bonding surface at the interface between the semiconductor ceramic and the magnetic ceramic, and furthermore, it is possible to obtain a bonding force sufficient for commercialization. It can be said that it is extremely difficult.

  Japanese Patent Laid-Open No. 9-283339 proposes that an intermediate layer made of a mixture of a magnetic material composition and a varistor composition is provided between the inductor block and the varistor block. However, it is difficult to avoid the occurrence of cracks on the magnetic composition side simply by providing an intermediate layer made of a mixture. Furthermore, it can be said that it is difficult to make the entire device compact by reducing the thickness of the intermediate layer as much as possible.

  Further, the inductor element portion specified by the present invention as the one-side element to be joined is made of nonmagnetic ferrite and forms a so-called air-core coil. Inductors that make up an air-core coil have the advantage of exhibiting good characteristics up to a higher frequency range, but have the problem of space that the coil must be wound many times because the core is non-magnetic. The size of the inductor itself is slightly larger than when a normal magnetic ferrite substrate is used. Therefore, there is a special circumstance that it is required to make the composite layered sintered product compact by reducing the thickness of the intermediate layer provided for joining as much as possible.

Japanese Patent Laid-Open No. 7-220906 JP 7-22210 A Japanese Patent Laid-Open No. 9-283339

  The present invention was devised based on such a situation, and its purpose is to generate cracks in a varistor element part having a varistor layer and an internal electrode, and an inductor element part having a ferrite layer and an internal conductor. Providing a composite multilayer electronic component that can be securely joined and integrated without causing any problems, etc., and the thickness of the joining intermediate layer for joining can be set as thin as possible. There is to do.

  In order to solve such a problem, the present invention provides a varistor element part having a varistor layer and an internal electrode, an inductor element part having a ferrite layer and an internal conductor, and an intervening element for joining both of these element parts. The ferrite layer is made of non-magnetic Zn-based ferrite, the varistor layer is made of ZnO as a main component, and the bonding intermediate layer is It is configured by laminating first to N-th N layers (N is an integer of 2 or more) having different compositions, and has a total thickness of 240 μm or less. The difference between the linear expansion coefficients of the first bonding film in contact with the first bonding film is within 1 (ppm / K), and the adjacent bonding films constituting the N-1 bonding interface other than the first bonding film are adjacent to each other. of The difference in expansion coefficient is within 2 (ppm / K), and the difference between the linear expansion coefficients of the varistor layer and the Nth bonding film in contact with the varistor layer is within 2 (ppm / K). .

As a preferred embodiment of the present invention, the bonding intermediate layer is formed by laminating two layers of first to second bonding films having different compositions, and the total thickness thereof is 240 μm or less. The coefficient of linear expansion of the ferrite layer is α _f (ppm / K), the coefficient of linear expansion of the first bonding film in contact with this is α _C1 (ppm / K), and the first bonding film is in contact with the first bonding film. When the linear expansion coefficient of the second bonding film is α _C2 (ppm / K) and the linear expansion coefficient of the varistor layer in contact with the second bonding film is α _V (ppm / K),
α _f (ppm / K) −α _C1 (ppm / K) ≦ 1.0 (ppm / K)
α _C1 (ppm / K) −α _C2 (ppm / K) ≦ 2.0 (ppm / K)
α _C2 (ppm / K) −α _v (ppm / K) ≦ 2.0 (ppm / K)
It is configured to satisfy the relationship.

As a preferred embodiment of the present invention, the bonding intermediate layer is constituted by laminating first to third bonding films having different compositions, and a total thickness thereof is 240 μm or less. The coefficient of linear expansion of the ferrite layer is α _f (ppm / K), the coefficient of linear expansion of the first bonding film in contact with this is α _C1 (ppm / K), and the first bonding film is in contact with the first bonding film. The linear expansion coefficient of the second bonding film is α _C2 (ppm / K), the linear expansion coefficient of the third bonding film in contact with the second bonding film is α _C3 (ppm / K), and the third When the linear expansion coefficient of the varistor layer in contact with the second bonding film is α _V (ppm / K),
α _f (ppm / K) −α _C1 (ppm / K) ≦ 1.0 (ppm / K)
α _C1 (ppm / K) −α _C2 (ppm / K) ≦ 2.0 (ppm / K)
α _C2 (ppm / K) −α _C3 (ppm / K) ≦ 2.0 (ppm / K)
α _C3 (ppm / K) −α _v (ppm / K) ≦ 2.0 (ppm / K)
It is configured to satisfy the relationship.

  As a preferred embodiment of the present invention, the nonmagnetic Zn-based ferrite includes a composition in which a part of Zn or Fe is substituted with at least one of Ni, Mg, Mn, and Cu.

  As a preferred embodiment of the present invention, each bonding film constituting the bonding intermediate layer is configured by mixing a composition component constituting the ferrite layer and zinc oxide (ZnO) at a predetermined ratio.

  As a preferred embodiment of the present invention, the joining intermediate layer contains K, Na, or Li.

As a preferred embodiment of the present invention, the nonmagnetic Zn-based ferrite contains iron oxide in an amount of 40 to 50 mol% in terms of Fe ₂ O ₃ , and zinc oxide in a remaining mol% in terms of ZnO, and the varistor layer Is configured to contain 95 to 98 mol% of ZnO as its main component.

  The composite multilayer electronic component of the present invention includes a varistor element part having a varistor layer and an internal electrode, an inductor element part having a ferrite layer and an internal conductor, and a junction intermediate interposed for joining both of these element parts. The junction intermediate layer is formed by stacking first to N-th N-layer junction films (N is an integer of 2 or more) having different compositions, and the sum of them. The thickness is 240 μm or less, the difference in linear expansion coefficient between the ferrite layer of the inductor element portion and the first bonding film in contact therewith is within 1 (ppm / K), and other N− The difference in linear expansion coefficient between adjacent bonding films constituting one bonding interface is within 2 (ppm / K), and the varistor layer of the varistor element portion and the Nth bonding film in contact with the varistor layer The difference in linear expansion coefficient between the two is 2 ppm / K), it is possible to reliably bond and integrate without generating cracks at the bonding interface, and to reduce the thickness of the bonding intermediate layer for bonding. It can be set as thin as possible, and the parts can be made compact.

  The present invention relates to a composite laminate having a varistor element portion having a varistor layer and an internal electrode, an inductor element portion having a ferrite layer and an internal conductor, and a joining intermediate layer interposed to join both of the element portions. The main part of the present invention lies in the setting of the specifications of the joining intermediate layer that can surely join both of the above-described element parts, which has been difficult to join conventionally.

  Before describing the specification setting of the joining intermediate layer, which is the main part of the present invention, an explanation of the overall configuration of an example of a composite multilayer electronic component will be given with reference to FIGS. Note that the illustrated example is merely for schematically showing a state in which the varistor element portion and the inductor element portion are joined, and a modified component in which a chip capacitor or the like is further added thereto may be used.

  FIG. 1 is a perspective view showing a composite laminated electronic component. FIG. 2 is an exploded perspective view of a laminated body for easy understanding of the laminated structure of the composite laminated electronic component.

  As shown in FIG. 1, the composite multilayer electronic component 100 includes a substantially rectangular parallelepiped laminate 1, and the laminate 1 constitutes a main body of the multilayer electronic component 100. The laminated body 1 has a pair of side surfaces 9a and 9b facing each other, a pair of side surfaces 9c and 9d, and a pair of top surfaces 9e and bottom surfaces 9f, and these surfaces 9a to 9f have a substantially rectangular parallelepiped shape. Yes. The bottom surface 9f is a surface facing the external substrate when the composite multilayer electronic component 100 is mounted on the external substrate.

  The composite multilayer electronic component 100 includes an input terminal (first terminal electrode) 3 formed on the side surface 9a of the multilayer body 1 and an output terminal (second terminal electrode) 5 formed on the side surface 9b. And a pair of ground terminals (third terminal electrodes) 7 formed on the side surfaces 9c and 9d. The input terminal 3 covers the entire surface of the side surface 9a, and a part thereof is formed so as to wrap around the surfaces 9c to 9f. The output terminal 5 covers the entire surface of the side surface 9b, and a part of the output terminal 5 wraps around the surfaces 9c to 9f. Each ground terminal 7 extends in a strip shape in the stacking direction of the stacked body 1, and further, both end portions thereof are formed to wrap around the upper surface 9 e and the bottom surface 9 f.

  The composite multilayer electronic component 100 according to the present invention includes a varistor element portion 10 and an inductor element portion 20 as constituent members of the multilayer body 1 as shown in FIG.

[Description of Varistor Element Unit 10]
First, the configuration of the varistor element unit 10 will be described. The varistor element section 10 includes a plurality of varistor green sheets A2 and A3 on which hot electrodes B1 and ground electrodes B2 which are so-called internal electrodes and lead-out sections B1a and B2a are formed (four sheets in the first embodiment). ) Varistor green sheets A1 to A4 are laminated. The hot electrode B1 is a varistor electrode for signals, and the ground electrode B2 is a varistor electrode for grounding.

  The actual composite multilayer electronic component 100 is integrated to such an extent that the boundaries between the varistor green sheets A1 to A4 cannot be visually recognized. The varistor green sheets A1 to A4 function as a varistor layer by firing.

The varistor green sheets A1 to A4 are formed, for example, by applying a slurry using a mixed powder of ZnO, Co ₃ O ₄ , Pr ₆ O ₁₁ , CaCO ₃ , and SiO ₂ as a raw material on a film by a doctor blade method. . Due to the composition of the varistor green sheets A1 to A4, voltage non-linearity in which the resistance value changes non-linearly with respect to the applied voltage appears. The thickness of the varistor green sheets A1 to A4 is, for example, about 30 μm. The composition of the varistor green sheets A1 to A4 will be described in detail later.

  The relationship between the varistor green sheet and the electrode will be described in further detail. A hot electrode B1 and a lead-out portion B1a are formed on the surface of the varistor green sheet A2, and the hot electrode B1 has a substantially rectangular shape that is slightly smaller than the varistor green sheet A2. The hot electrode B1 is integrally formed with a lead-out portion B1a at the center of one short side. The lead-out part B1a of the hot electrode B1 has a substantially rectangular shape, is drawn to the edge of the varistor green sheet A2, and its end is exposed at the end face of the varistor green sheet A2. For this reason, the lead-out part B1a of the hot electrode B1 is electrically connected to the input terminal 3.

  A ground electrode B2 and a lead-out portion B2a are formed on the surface of the varistor green sheet A3. The ground electrode B2 has a substantially rectangular shape that is slightly smaller than the varistor green sheet A3. In the ground electrode B2, a pair of lead-out portions B2a are integrally formed at the center of both short sides. The lead-out part B2a of the ground electrode B2 has a substantially rectangular shape, is drawn out to the edge of the varistor green sheet A3, and its end is exposed at the end face of the varistor green sheet A3. For this reason, the lead-out part B2a of the ground electrode B2 is connected to each ground terminal 7 respectively.

  As described above, the varistor green sheets A1 to A4 are laminated, and the varistor V is configured by sandwiching the varistor green sheet A2 between the hot electrode B1 and the ground electrode B2. The hot electrode B1, the ground electrode B2, and the lead-out portions B1a and B2a are formed, for example, by screen-printing a paste mainly composed of Pd on the varistor green sheets A2 and A3. The thicknesses of the hot electrode B1, the ground electrode B2, and the lead-out portions B1a and B2a are set to about 5 μm, for example.

[Description of Inductor Element 20]
Next, one configuration example of the inductor element unit 20 will be described. The inductor element portion 20 includes a plurality (seven in this first embodiment) of inductor element portions having a ferrite layer and an inner conductor, and inductor green sheets A6 to A11 including conductor patterns B3 to B13 which are inner conductors. Inductor green sheets (ferrite layers) A5 to A12 are laminated. The actual composite multilayer electronic component 100 is integrated to such an extent that the boundary between the inductor green sheets A5 to A12 cannot be visually recognized. The inductor green sheets A5 to A12 function as an insulating layer when fired.

  The inductor green sheets A5 to A12 are insulators having electrical insulation.

  The inductor green sheets A5 to A12 in the present invention are formed by applying a slurry made of nonmagnetic Zn-based ferrite as a raw material onto a film by a doctor blade method. The thickness of the inductor green sheets A5 to A12 is, for example, about 20 μm.

  On the surface of the inductor green sheet A6, the conductor patterns B3 and B8 are juxtaposed in the longitudinal direction of the inductor green sheet A6 with a predetermined interval therebetween. The conductor patterns B3 and B8 are electrically insulated from each other. Each of the conductor patterns B3 and B8 corresponds to approximately 1/2 turn of coil formation, and is formed in an approximately L shape. Derived portions B3a and B8a are integrally formed at one end of each conductor pattern B3 and B8. The lead-out portions B3a and B8a of the conductor patterns B3 and B8 are respectively drawn out to the edge of the inductor green sheet A6, and the respective end portions are exposed at the end face of the inductor green sheet A6. For this reason, the lead-out part B3a is electrically connected to the input terminal 3, and the lead-out part B8a is electrically connected to the output terminal 5.

  The other end of each conductor pattern B3, B8 is electrically connected to through-hole electrodes C1, C6 formed through the inductor green sheet A6 in the thickness direction. Therefore, each conductor pattern B3, B8 is electrically connected to one end of each corresponding conductor pattern B4, B9 via the through-hole electrodes C1, C6 in a state where the multilayer body 1 is laminated.

  On the surface of the inductor green sheet A7, the conductor patterns B4 and B9 are juxtaposed in the longitudinal direction of the inductor green sheet A7 with a predetermined distance therebetween. The conductor patterns B4 and B9 are electrically insulated from each other. Each of the conductor patterns B4 and B9 corresponds to approximately 3/4 turns of coil formation, and is formed in a substantially U shape.

  One end of each conductor pattern B4, B9 includes a region electrically connected to each through-hole electrode C1, C6 in a state where the multilayer body 1 is laminated. The other end of each conductor pattern B4, B9 is electrically connected to each through-hole electrode C2, C7 formed through the inductor green sheet A7 in the thickness direction. Therefore, each conductor pattern B4, B9 is electrically connected to one end of each corresponding conductor pattern B5, B10 via each through-hole electrode C2, C7 in a state where the multilayer body 1 is laminated.

  On the surface of the inductor green sheet A8, the conductor patterns B5 and B10 are juxtaposed in the longitudinal direction of the inductor green sheet A8 with a predetermined distance therebetween. The conductor patterns B5 and B10 are electrically insulated from each other. Each of the conductor patterns B5 and B10 corresponds to approximately 3/4 turns of coil formation, and is formed in a substantially C shape. One end of each of the conductor patterns B5 and B10 includes a region electrically connected to each of the through-hole electrodes C2 and C7 in a state where the multilayer body 1 is laminated. The other end of each conductor pattern B5, B10 is electrically connected to each through-hole electrode C3, C8 formed through the inductor green sheet A8 in the thickness direction. Therefore, each conductor pattern B5, B10 is electrically connected to one end of each corresponding conductor pattern B6, B11 via each through-hole electrode C3, C8 in a state where the multilayer body 1 is laminated.

  On the surface of the inductor green sheet A9, the conductor patterns B6 and B11 are juxtaposed in the longitudinal direction of the inductor green sheet A9 with a predetermined distance therebetween. The conductor patterns B6 and B11 are electrically insulated from each other. Each of the conductor patterns B6 and B11 corresponds to approximately 3/4 turns of coil formation, and is formed in a substantially U shape. One end of each of the conductor patterns B6 and B11 includes a region electrically connected to each of the through-hole electrodes C3 and C8 in a state where the multilayer body 1 is laminated. The other end of each conductor pattern B6, B11 is electrically connected to each through-hole electrode C4, C9 formed through the inductor green sheet A9 in the thickness direction. Therefore, each conductor pattern B6, B11 is electrically connected to one end of each corresponding conductor pattern B7, B12 via each through-hole electrode C4, C9 in a state where the multilayer body 1 is laminated.

  On the surface of the inductor green sheet A10, the conductor patterns B7 and B12 are juxtaposed in the longitudinal direction of the inductor green sheet A10 with a predetermined interval therebetween. The conductor patterns B7 and B12 are electrically insulated from each other. Each of the conductor patterns B7 and B12 corresponds to approximately 1/2 turn of coil formation, and is formed in a substantially C shape. One end of each of the conductor patterns B7 and B12 includes a region electrically connected to each of the through-hole electrodes C4 and C9 in a state where the multilayer body 1 is laminated. The other end of each conductor pattern B7, B12 is electrically connected to each through-hole electrode C5, C10 formed through the inductor green sheet A10 in the thickness direction. For this reason, each conductor pattern B7, B12 is each electrically connected with each edge part of the corresponding conductor pattern B13 via each through-hole electrode C5, C10 in the state which the laminated body 1 was laminated | stacked.

  As described above, the inductor green sheets A5 to A11 are laminated, and the conductor patterns B3 to B7 are electrically connected to each other through the through-hole electrodes C1 to C4, thereby forming one coil. Will be. Moreover, another coil is comprised by each conductor pattern B8-B12 being mutually electrically connected via each through-hole electrode C6-C9.

  On the surface of the inductor green sheet A11, a conductor pattern B13 extends in the longitudinal direction of the inductor green sheet A11 and is formed in a substantially I shape. The positions corresponding to both ends of the conductor pattern B13 include regions that are electrically connected to the through-hole electrodes C5 and C10 in a state where the multilayer body 1 is laminated. Thereby, two coils are electrically connected in series.

  The conductor patterns B3 to B13 and the through-hole electrodes C1 to C11 are formed, for example, by screen-printing a paste mainly containing Pd on the inductor green sheets A6 to A11. The thickness of the conductor patterns B3 to B13 is, for example, about 14 μm.

[ Explanation of bonding interlayer ]
Between the varistor element portion 10 and the inductor element portion 20, a bonding intermediate layer 50 for bonding these element portions is interposed.

  The junction intermediate layer 50 in the present invention is configured by laminating first to Nth junction films having different compositions (in the example of FIG. 2, three junction layers A20 to A22 are illustrated). Have been). In the N-layer bonding film constituting the bonding intermediate layer 50 in the present invention, the following linear expansion coefficient is set at the bonding interface.

  That is, the difference in linear expansion coefficient between the ferrite layer forming the main part of the so-called substrate of the inductor element 20 and the first bonding film in contact with the ferrite layer is within 1 (ppm / K) (particularly preferably 0). .6 (ppm / K) or less, and the difference in linear expansion coefficient between adjacent bonding films constituting the other N-1 bonding interfaces is within 2 (ppm / K) (particularly preferable). Is within 1 (ppm / K)), and the difference in linear expansion coefficient between the varistor layer forming the main part of the base of the varistor element portion 10 and the Nth bonding film in contact therewith is 2 (ppm / K) (particularly preferably within 1 (ppm / K)). When the desired difference in linear expansion coefficient defined in this way cannot be obtained, the thickness of the junction intermediate layer 50 is reduced as will be described later, and the inductor element portion 20 and the varistor element portion 10 are cracked. It will no longer be possible to reliably join and integrate without occurrence.

  N is an integer of 2 or more, preferably N = 2 to 5, more preferably N = 2 to 4, and still more preferably N = 2 to 3. Although there is no restriction | limiting in particular in the upper limit of N, The compounding composition number of the joining film | membrane which must be prepared as N increases will increase.

  The total thickness of the joining intermediate layer 50 is 240 μm or less, preferably 180 μm or less. If this value exceeds 240 μm, one of the purposes of the present application, which is to make the composite integrated sintered product compact by reducing the thickness of the joining intermediate layer provided for joining as much as possible, cannot be realized. That is, the inductor element portion, which is a one-side element to be joined by the present invention, is made of nonmagnetic ferrite and forms a so-called air-core coil. Inductors that make up an air-core coil have the advantage of exhibiting good characteristics up to a higher frequency range, but have the problem of space that the coil must be wound many times because the core is non-magnetic. The size of the inductor itself tends to be larger than when a normal magnetic ferrite substrate is used. Therefore, it is required to reduce the thickness of the intermediate layer provided for joining as much as possible to achieve a compact composite integrated sintered product.

  The description will be made by limiting the number N of the bonding films constituting the bonding intermediate layer 50 to a specific number.

In the case of N = 2, the junction configuration is as shown in FIG. That is, as shown in FIG. 3, the bonding intermediate layer 50 is configured by stacking two layers of first to second bonding films 51 and 52 having different compositions, and the total thickness thereof. Is 240 μm or less. The linear expansion coefficient of the ferrite layer A5 constituting the inductor element portion 20 is α _f (ppm / K), and the linear expansion coefficient of the first bonding film 51 in contact therewith is α _C1 (ppm / K). The linear expansion coefficient of the second bonding film 52 in contact with the first bonding film 51 is α _C2 (ppm / K). The coefficient of linear expansion of the varistor layer A4 in contact with the second bonding film 52 is α _V (ppm / K). In such a laminated state, in the present invention,

α _f (ppm / K) −α _C1 (ppm / K) ≦ 1.0 (ppm / K)
α _C1 (ppm / K) −α _C2 (ppm / K) ≦ 2.0 (ppm / K)
α _C2 (ppm / K) −α _v (ppm / K) ≦ 2.0 (ppm / K)
Are configured so as to satisfy each of the relationships.

In the case of N = 3, the junction configuration is as shown in FIG. That is, as shown in FIG. 4, the bonding intermediate layer 50 is configured by laminating three layers of first to third bonding films having different compositions, and the total thickness thereof is 240 μm or less. It is said.
The linear expansion coefficient of the ferrite layer A5 constituting the inductor element portion 20 is α _f (ppm / K), and the linear expansion coefficient of the first bonding film 51 in contact therewith is α _C1 (ppm / K). Then, the linear expansion coefficient of the second bonding film 52 in contact with the first bonding film 51 is α _C2 (ppm / K), and the third bonding film 53 in contact with the second bonding film 52 is used. _Is defined as α _C3 (ppm / K). The coefficient of linear expansion of the varistor layer A4 in contact with the third bonding film 53 is α _V (ppm / K). In such a laminated state, in the present invention,

α _f (ppm / K) −α _C1 (ppm / K) ≦ 1.0 (ppm / K)
α _C1 (ppm / K) −α _C2 (ppm / K) ≦ 2.0 (ppm / K)
α _C2 (ppm / K) −α _C3 (ppm / K) ≦ 2.0 (ppm / K)
α _C3 (ppm / K) −α _v (ppm / K) ≦ 2.0 (ppm / K)
Are configured so as to satisfy each of the relationships.

  Each bonding film of the bonding intermediate layer configured to maintain such a linear expansion coefficient relationship includes a composition component constituting the ferrite layer of the inductor element portion and zinc oxide (ZnO) (varistor layer of the varistor element portion). It is desirable that the composition component is mixed at a predetermined ratio. At that time, the bonding film disposed closer to the ferrite layer contains more ferrite layer composition components, and conversely, the bonding film disposed closer to the varistor layer has more zinc oxide (ZnO). It may be blended so as to include (may be a composition component constituting the varistor layer of the varistor element portion).

  Generally, since the coefficient of linear expansion of the ferrite layer of the inductor element portion is the largest, it is desirable to adjust the composition of each bonding film so that the coefficient of linear expansion gradually decreases toward the varistor layer of the varistor element portion. .

  In addition, the linear expansion coefficient (ppm / K) used by this invention is a value of the arithmetic average of the linear expansion coefficient in 200 to 700 degreeC.

  Furthermore, it is desirable to add K, Na, or Li to each bonding film of the bonding intermediate layer. This is because the resistance lowered by mixing the varistor layer composition component and the ferrite layer composition component is increased.

[ Description of the composition of the ferrite layer of the inductor element ]
The ferrite layer of the inductor element portion of the present invention is composed of nonmagnetic Zn-based ferrite. The nonmagnetic Zn-based ferrite in the present invention contains 40 to 50 mol% of iron oxide in terms of Fe ₂ O ₃ and the remaining mol% of zinc oxide in terms of ZnO. The nonmagnetic Zn-based ferrite in the present invention also includes a composition in which a part of Zn or Fe is substituted with at least one of Ni, Mg, Mn, and Cu. The substitution of Ni, Mg, Mn and Cu is within 10 mol%.

Furthermore, as an additive component, SiO ₂ , CaCO ₃ , ZrO ₂ , SnO ₂ , TiO ₂ , MoO ₃ , Bi ₂ O ₃ , WO ₃ , CoO and the like may be contained at about 1 wt%.

[ Description of the composition of the varistor layer of the varistor element ]
Varistor layer, ZnO is its main component, 95 mol% or more, in particular 95 to 98 mol% containing chromatic. Furthermore, Co, Pr, etc. are contained as subcomponents.

  Next, a method for manufacturing the composite multilayer electronic component 100 shown in FIGS. 1 and 2 will be described. First, varistor green sheets A1 to A4, inductor green sheets A5 to A12, and bonding film green sheets A20 to A22 as bonding intermediate layers are prepared.

  Next, through holes are formed by laser processing or the like at predetermined positions of the inductor green sheets A6 to A11, that is, positions where the through hole electrodes C1 to C10 are to be formed.

  Next, the hot electrode B1, the ground electrode B2, and the lead-out portions B1a and B2a are formed on the varistor green sheets A2 and A3, respectively. Conductor patterns B3 to B13 and lead-out portions B3a and B8a are formed on the inductor green sheets A6 to A11, respectively. Further, the through-hole electrodes C1 to C10 are formed.

  Next, the varistor green sheets A1 to A4, the inductor green sheets A5 to A12, and the bonding film green sheets A20 to A22 as bonding intermediate layers are laminated in the order shown in FIG. Then, after cutting into chips, firing is performed at a predetermined temperature (for example, 1100 to 1200 ° C.).

  Thereby, it integrates to such an extent that the boundary between each green sheet cannot be visually recognized, and the laminated body 1 will be formed.

  Next, the input terminal 3, the output terminal 5, and the ground terminal 7 are formed on the laminate 1. Thereby, the multilayer electronic component E1 is formed. The input terminal 3, the output terminal 5 and the ground terminal 7 are baked at a predetermined temperature (for example, 600 to 700 ° C.) after transferring the electrode paste mainly composed of silver to the side surfaces 9a to 9d of the laminate 1, respectively. It is formed by applying electroplating. For electroplating, Ni and Sn, Cu and Ni and Sn, Ni and Au, Ni and Pd and Au, Ni and Pb and Ag, Ni and Ag, or the like can be used.

  Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention.

Experimental example 1
[Fabrication of nonmagnetic Zn-based ferrite layer for inductor element]
Weighing was performed so that Fe ₂ O ₃ was 49 mol% and ZnO was 51 mol%. Pure water was added to this weighed product and mixed with a ball mill for 24 hours to form a slurry.

  The slurry was dried and calcined at a temperature of 900 ° C. for 2 hours.

  Next, pure water was added to the calcined product and further pulverized.

  Next, after the obtained fine powder was dried, it was dispersed in a solvent together with an organic binder to form a slurry.

  Thereafter, a ferrite sheet having a thickness of 20 μm was produced from this slurry by a doctor blade method.

[Production of varistor layer forming material for varistor element]
Main component ZnO is 97 mol% is, Co ₃ O ₄ is 1 mol%, Pr ₆ O ₁₁ is 1 mol%, so that CaCO ₃ is 0.5 mol%, and SiO ₂ is 0.5 mol% Weighed. This weighed product was dispersed in a solvent together with an organic binder to form a slurry.

  Thereafter, a green sheet for a varistor having a thickness of 30 μm was produced from this slurry by a doctor blade method.

[Preparation of bonding film constituting bonding intermediate layer]
As shown in Table 1 below, bonding films composed of five types of CM0, CM1, CM2, CM3 and CM4 compositions having different blending compositions were prepared. That is, the composition of the varistor layer (shown as Ferrite in Table 1) and the composition of the ferrite layer (shown as Varister in Table 1) are in five ratios as shown in Table 1. 5 kinds of bonding film green sheets were prepared. The thickness of the bonding film green sheet was 20 μm, 30 μm and 45 μm.

  In Table 1, the linear expansion coefficient α (ppm / K) of five types of bonding films, ferrite layers, and varistor layers having different blending compositions is shown at the same time.

  A ferrite layer and a varistor layer were subjected to a joining experiment using various joining layers having various thicknesses and compositions as shown in Table 2 by combining various types of the five joining films shown in Table 1 above.

  That is, 18 ferrite layers having a thickness of 20 μm composed of the above composition, 10 bonding intermediate layers shown in Table 2, and 10 varistor layers having a thickness of 30 μm composed of the above composition were laminated, and a pressure of 100 MPa was applied in the laminating direction. To form a laminate. Next, this laminate was cut into a predetermined size, and then fired at 1150 ° C. for 1 hour to prepare a sintered body sample.

  About the sintered compact sample produced in such a way, the presence or absence of the crack generation | occurrence | production in a joining interface was confirmed in the following way.

Method for confirming the presence or absence of cracks The samples were polished, the internal cross section was observed with an optical microscope, and the number of cracked samples was counted to determine the number of cracks generated.

  In addition, the sintered compact sample was set to n = 50. In particular, it has been confirmed that cracks are generated at locations where the joining intermediate layer and the ferrite layer are in contact with each other, and are frequently generated on the ferrite layer side. Further, in the present invention, this method is sufficient as an experiment for confirming the presence or absence of cracks at the joint portion, although it is an experiment in a state where the internal electrode, the internal conductor, and further the external electrode are not formed. It has been confirmed by a correlation experiment with a composite multilayer electronic component that is a finished product.

The effect of the present invention is clear from the results shown in Table 2.
That is, in the present invention 1 to the present invention 3 shown in Table 2, the difference in linear expansion coefficient between the ferrite layer and the first bonding film in contact with the ferrite layer is within 1 (ppm / K), The difference in mutual linear expansion coefficient between adjacent bonding films constituting the other N-1 bonding interfaces is within 2 (ppm / K), and the varistor layer and the Nth bonding film in contact therewith The difference in linear expansion coefficient between the ferrite layer and the varistor layer can be reliably joined and integrated without generating cracks. it can. In addition, the thickness of the joining intermediate layer for joining can be set as thin as possible, and joining with a total thickness of 90 μm in the present invention 1, 120 μm in the present invention 2 and 120 μm in the present invention 3 becomes possible. ing.

  On the other hand, in Comparative Example 1, since the difference in linear expansion coefficient between the ferrite layer and CM2 exceeds 1 (ppm / K), if the total thickness of the bonding film is not increased to 270 μm, cracks will occur. Occurrence cannot be prevented. Further, in Comparative Example 2, since the difference in linear expansion coefficient between the bonding films exceeds 2 (ppm / K), generation of cracks is prevented unless the total thickness of the bonding films is increased to 270 μm. Can not. In Comparative Example 3, since the difference in linear expansion coefficient between the ferrite layer and CM2 exceeds 1 (ppm / K) as in Comparative Example 1, the total thickness of the bonding film is 270 μm. If it is not thick enough, the occurrence of cracks cannot be prevented. Further, in Comparative Example 4, since the difference in linear expansion coefficient between the varistor layer and the bonding film in contact with the varistor layer exceeds 2 (ppm / K), the total thickness of the bonding film is 270 μm. If it is not thick enough, the occurrence of cracks cannot be prevented.

Experimental example 2
The material for forming the nonmagnetic Zn-based ferrite layer of the inductor element portion in Experimental Example 1 was changed as follows.

That is, they were weighed so that Fe ₂ O ₃ was 49 mol%, CuO was 2 mol%, ZnO was 39 mol%, and NiO was 10 mol. Other than that, a nonmagnetic Zn-based ferrite layer was prepared in the same manner as in Experimental Example 1 and the same experiment as in Experimental Example 1 was performed. The same experimental results as shown in Table 2 were obtained. I was able to confirm.

Experimental example 3
The material for forming the nonmagnetic Zn-based ferrite layer of the inductor element portion in Experimental Example 1 was changed as follows.

That is, it was weighed so that Fe ₂ O ₃ was 49 mol%, CuO was 2 mol%, ZnO was 39 mol%, and MgO was 10 mol. Other than that, a nonmagnetic Zn-based ferrite layer was prepared in the same manner as in Experimental Example 1 and the same experiment as in Experimental Example 1 was performed. The same experimental results as shown in Table 2 were obtained. I was able to confirm.

Experimental Example 4
The material for forming the nonmagnetic Zn-based ferrite layer of the inductor element portion in Experimental Example 1 was changed as follows.

That is, it was weighed so that Fe ₂ O ₃ was 47 mol%, CuO was 2 mol%, ZnO was 49 mol%, and Mn ₂ O ₃ was 2 mol%. Other than that, a nonmagnetic Zn-based ferrite layer was prepared in the same manner as in Experimental Example 1 and the same experiment as in Experimental Example 1 was performed. The same experimental results as shown in Table 2 were obtained. I was able to confirm.

  The composite multilayer electronic component of the present invention can be widely used in various electric component industries.

FIG. 1 is a perspective view showing a composite laminated electronic component. FIG. 2 is an exploded perspective view of a laminated body for easy understanding of the laminated structure of the composite laminated electronic component. FIG. 3 is a cross-sectional view for explaining a specific bonding state where the number N of bonding films constituting the bonding intermediate layer is two. FIG. 4 is a cross-sectional view for explaining a specific bonding state where the number N of bonding films constituting the bonding intermediate layer is three.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laminated body 10 ... Varistor element part 20 ... Inductor element part 50 ... Junction intermediate | middle layer 100 ... Composite laminated type electronic component

Claims (7)

A composite multilayer electronic component having a varistor element portion having a varistor layer and an internal electrode, an inductor element portion having a ferrite layer and an internal conductor, and a joining intermediate layer interposed to join both of the element portions. There,
The ferrite layer is made of nonmagnetic Zn-based ferrite,
The varistor layer is mainly composed of ZnO,
The junction intermediate layer is formed by stacking first to N-th N layers (N is an integer of 2 or more) having different compositions, and the total thickness thereof is 240 μm or less. Yes,
The difference in linear expansion coefficient between the ferrite layer and the first bonding film in contact with the ferrite layer is within 1 (ppm / K), and the adjacent bonding constituting the N-1 bonding interface other than that. The difference in linear expansion coefficient between the films is within 2 (ppm / K), and the difference in linear expansion coefficient between the varistor layer and the Nth bonding film in contact therewith is 2 (ppm / K). ) A composite multilayer electronic component characterized by comprising The bonding intermediate layer is configured by laminating two layers of first to second bonding films having different compositions, and the total thickness thereof is 240 μm or less.
The coefficient of linear expansion of the ferrite layer is α _f (ppm / K), the coefficient of linear expansion of the first bonding film in contact therewith is α _C1 (ppm / K), and the second value in contact with the first bonding film. When the linear expansion coefficient of the bonding film is α _C2 (ppm / K) and the linear expansion coefficient of the varistor layer in contact with the second bonding film is α _V (ppm / K),
α _f (ppm / K) −α _C1 (ppm / K) ≦ 1.0 (ppm / K)
α _C1 (ppm / K) −α _C2 (ppm / K) ≦ 2.0 (ppm / K)
α _C2 (ppm / K) −α _v (ppm / K) ≦ 2.0 (ppm / K)
The composite multilayer electronic component according to claim 1, wherein the relationship is satisfied. The bonding intermediate layer is configured by laminating three layers of first to third bonding films having different compositions, and the total thickness thereof is 240 μm or less.
The coefficient of linear expansion of the ferrite layer is α _f (ppm / K), the coefficient of linear expansion of the first bonding film in contact therewith is α _C1 (ppm / K), and the second value in contact with the first bonding film. Α _C2 (ppm / K) for the linear expansion coefficient of the bonding film, α _C3 (ppm / K) for the third bonding film in contact with the second bonding film, and the third bonding. When the coefficient of linear expansion of the varistor layer in contact with the film is α _V (ppm / K),
α _f (ppm / K) −α _C1 (ppm / K) ≦ 1.0 (ppm / K)
α _C1 (ppm / K) −α _C2 (ppm / K) ≦ 2.0 (ppm / K)
α _C2 (ppm / K) −α _C3 (ppm / K) ≦ 2.0 (ppm / K)
α _C3 (ppm / K) −α _v (ppm / K) ≦ 2.0 (ppm / K)
The composite multilayer electronic component according to claim 1, wherein the relationship is satisfied.   4. The composite laminate according to claim 1, wherein the nonmagnetic Zn-based ferrite includes a composition in which a part of Zn or Fe is substituted with at least one of Ni, Mg, Mn, and Cu. Type electronic components.   5. Each of the bonding films constituting the bonding intermediate layer is formed by mixing a composition component constituting the ferrite layer and zinc oxide (ZnO) at a predetermined ratio. A composite multilayer electronic component according to claim 1.   6. The composite multilayer electronic component according to claim 1, wherein the bonding intermediate layer contains K, Na, or Li. The Zn ferrite of the non-magnetic, 40-50 mol% of iron oxide in terms of Fe ₂ O _3, zinc oxide has been remaining mol% in terms of ZnO,
The composite multilayer electronic component according to any one of claims 1 to 6, wherein the varistor layer contains 95 to 98 mol% of ZnO as a main component thereof.

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