JP2011040793A - Collective substrate and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a collective substrate to produce a varistor that permits effectively dissipating heat, while preventing warpage. <P>SOLUTION: In a step of preparation, varistor green sheets, inner electrode patterns and heat dissipating green sheets are prepared, and in a stacking step S5, these green sheets are stacked to provide green stacked products. Thereafter, in a sintering step S6, the green stacked products are sintered to produce the collective substrate. The green stacked products formed in the stacking step each includes a first and a second varistor green section and a heat dissipating green section. The first and the second varistor green section have each a varistor green layer and a plurality of inner electrode patterns disposed in the varistor green layer. The heat dissipating green section has a pair of planes that face each other with one plane joined to a plane of the first varistor green section and the other plane joined to a plane of the second varistor green section. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a collective substrate, a method for producing the collective substrate, and a varistor.

  As a varistor, formed in a substantially rectangular parallelepiped varistor portion that expresses voltage non-linear characteristics, and an element body having a pair of internal electrodes facing each other across a part of the varistor part, and an outer surface of the element body, Some have a pair of terminal electrodes respectively connected to corresponding internal electrodes (see, for example, Patent Document 1).

JP 2002-246207 A

  By the way, the varistor can be protected from an ESD (Electrostatic Discharge) surge by being connected in parallel to an electronic element such as a semiconductor light emitting element or an FET (Field Effect Transistor). Some of these electronic elements generate heat during operation. When the electronic element becomes high temperature, the characteristic of the element itself is deteriorated and the operation is affected. For this reason, it is necessary to efficiently dissipate the generated heat.

  Therefore, the present inventors thought that heat can be efficiently dissipated from the varistor by providing a heat dissipating part having a heat dissipating function so as to contact the varistor part and dissipating the heat transferred to the varistor from the heat dissipating part. . However, this case has the following problems.

  In a conventional varistor manufacturing process, an aggregate substrate including a plurality of element bodies is formed. The collective substrate is obtained by laminating a plurality of varistor green sheets serving as varistor portions and electrode patterns serving as internal electrodes to form a laminated green body and firing the laminated green body.

  When manufacturing a varistor with a heat dissipating part, the collective substrate is laminated with a heat dissipating green sheet serving as a heat dissipating part on a varistor part comprising a plurality of varistor green sheets serving as varistor parts and an electrode pattern serving as an internal electrode. Thus, a laminated green body is formed and fired. When such a laminated green body is fired, the varistor portion and the heat radiating portion have different shrinkage rates, which causes a problem in that the collective substrate is warped.

  Accordingly, an object of the present invention is to provide a varistor capable of efficiently radiating heat and a flat aggregate substrate for manufacturing the varistor. Another object of the present invention is to provide a method for manufacturing a collective substrate that prevents warping for manufacturing a varistor capable of efficiently radiating heat.

  The collective substrate of the present invention includes a first varistor element layer that exhibits voltage nonlinear characteristics, and a plurality of first varistor elements arranged in the extending direction of the first varistor element layer in the first varistor element layer. A first varistor section having a first main surface and a second main surface facing each other, a second varistor element layer that exhibits voltage nonlinear characteristics, and a second varistor element layer. A plurality of second internal electrodes arranged in the extending direction of the second varistor element layer, and having a third main surface and a fourth main surface facing each other. A second varistor portion and a heat dissipation layer having a fifth main surface and a sixth main surface facing each other, wherein the fifth main surface of the heat dissipation layer is the second main surface of the first varistor portion. The sixth main surface of the heat dissipation layer is in contact with the fourth main surface of the second varistor part.

  The collective substrate of the present invention is configured by sandwiching a heat dissipation layer between a first varistor part and a second varistor part. Since the collective substrate of the present invention is formed in a flat plate shape and includes a heat dissipation layer, an element body having high heat dissipation efficiency can be easily manufactured using the collective substrate.

  In the collective substrate of the present invention, the first varistor section has a plurality of pairs of first surface electrodes formed on the first main surface at least partially facing each of the plurality of first internal electrodes. The second varistor part preferably has a plurality of pairs of second surface electrodes formed on the third main surface at least partially facing each of the plurality of second internal electrodes.

  In the collective substrate of the present invention, the first varistor section has a plurality of third internal electrodes facing each of the plurality of first internal electrodes in the opposing direction of the first main surface and the second main surface. The second varistor part preferably has a plurality of fourth internal electrodes facing each of the plurality of second internal electrodes in the opposing direction of the third main surface and the fourth main surface.

  In the collective substrate of the present invention, a plurality of first external electrodes electrically connected to one of the first surface electrodes in each pair of the plurality of pairs of first surface electrodes, and a plurality of pairs of first electrodes. It is also preferable to include a plurality of second external electrodes electrically connected to the other first surface electrode in each pair of the surface electrodes.

  In the collective substrate of the present invention, a plurality of first external electrodes electrically connected to each of the plurality of first internal electrodes, and a plurality of second electrodes electrically connected to each of the plurality of second internal electrodes. It is also preferable to provide the external electrode.

  Thus, by forming the external electrodes on the collective substrate, a plurality of varistors with high heat dissipation efficiency can be easily manufactured.

  The method for producing a collective substrate of the present invention includes a varistor green sheet containing a varistor composition powder for forming a varistor layer that exhibits voltage nonlinear characteristics, a varistor green sheet on which an internal electrode pattern is formed, and a heat dissipation layer. A preparatory step of preparing a predetermined number of heat dissipating green sheets to form, and laminating the varistor green sheet prepared in the preparatory step, the varistor green sheet on which the internal electrode pattern is formed, and the heat dissipating green sheet. And a laminating step of forming a green laminate having a first varistor green portion, a second varistor green portion, and a heat dissipating green portion, and a firing step of firing the green laminate to obtain an aggregate substrate. In the stacking step, the first varistor green part is stacked with the varistor green sheet. A first varistor green layer formed in the first varistor green layer, and a plurality of internal electrode patterns arranged in the extending direction of the first varistor green layer in the first varistor green layer. And the second varistor green portion includes a second varistor green layer in which the varistor green sheets are laminated, and the second varistor green layer includes the second varistor green layer. A plurality of internal electrode patterns arranged in the extending direction of the varistor green layer, and having a third main surface and a fourth main surface facing each other, wherein the heat dissipation green part is the heat dissipation green The sheet is formed by laminating sheets and has a fifth main surface and a sixth main surface facing each other, and the fifth main surface of the heat dissipation green portion is the first varistor green portion. The varistor green sheet and the interior are in contact with the second main surface, and the sixth main surface of the heat dissipating green portion is in contact with the fourth main surface of the second varistor green portion. The green laminate is formed by laminating a varistor green sheet on which an electrode pattern is formed and the heat dissipation green sheet.

  In the method for manufacturing a collective substrate of the present invention, even if the shrinkage rate during firing of the heat dissipating green part differs from the shrinkage rate during firing of the first and second varistor green parts, The first varistor green part is in contact with the main surface of the heat sink, the second varistor green part is in contact with the sixth main surface of the heat dissipation green part, and the heat dissipation green part is connected to the first varistor green part and the second varistor. Since it is sandwiched between the green portions, it is possible to prevent the occurrence of warpage during firing and form a planar aggregate substrate.

  In the preparation method of the collective substrate of the present invention, a predetermined number of surface electrode patterns are prepared in the preparation step, and the green laminate formed in the lamination step has the first varistor green portion arranged in the first varistor green portion. Further, each of the plurality of internal electrode patterns further includes a pair of surface electrode patterns formed on the first main surface so as to face each other, and the second varistor green portion includes the second varistor green. It is also preferable that at least a part of each of the plurality of internal electrode patterns arranged in the part further has a pair of surface electrode patterns formed on the third main surface.

  According to the method for manufacturing an aggregate substrate of the present invention, the green laminate formed in the laminating step is configured such that the first varistor green part has the first and second internal electrode patterns arranged in the first varistor green part. A plurality of internal electrode patterns disposed in the first varistor green layer so as to be at least partially opposed to each other in the opposing direction of the main surface, wherein the second varistor green part is formed in the second varistor green part. It is also preferable that each of the plurality of arranged internal electrode patterns further includes a plurality of internal electrode patterns arranged in the second varistor green layer so as to be at least partially opposed in the opposing direction of the third and fourth main surfaces. .

  The varistor of the present invention includes an element body having a first varistor part, a second varistor part, and a heat dissipation part, and a pair of external electrodes formed on the element body, and the first varistor parts are mutually connected. A first varistor element body having first and second surfaces facing each other and exhibiting a voltage non-linear characteristic; a first internal electrode disposed in the first varistor element; A first pair of surface electrodes disposed on the first surface at least partially facing the internal electrode, and the second varistor portion includes a third surface and a fourth surface facing each other. A second varistor element body having a non-linear characteristic, a second internal electrode disposed in the second varistor element body, and at least a part facing the second internal electrode. And a second pair of surface electrodes disposed on the third surface, and the heat radiating portions face each other The fifth surface is in contact with the second surface of the first varistor part, the sixth surface is in contact with the fourth surface of the second varistor part, The pair of external electrodes are electrically connected to the first pair of surface electrodes, respectively.

  The varistor of the present invention includes an element body having a first varistor part, a second varistor part, and a heat dissipation part, and a pair of external electrodes formed on the element body, and the first varistor parts are mutually connected. A first varistor element body having first and second surfaces facing each other and expressing a voltage nonlinear characteristic, and a facing direction of the first and second surfaces disposed in the first varistor element body And the second varistor section has a third surface and a fourth surface facing each other, and exhibits a voltage nonlinear characteristic. A varistor element body; and third and fourth internal electrodes disposed in the second varistor element element and facing in the opposing direction of the third and fourth surfaces; And the sixth surface is in contact with the second surface of the first varistor portion, and the sixth surface is the second varistor portion. In contact with the fourth surface, a pair of external electrodes is characterized in that it is connected to the first and second internal electrodes electrically.

  According to the method for manufacturing a collective substrate of the present invention, it is possible to manufacture a flat aggregate substrate in which warpage is prevented. Further, since the collective substrate of the present invention is formed in a flat plate shape, a varistor capable of efficiently radiating heat can be easily manufactured using the collective substrate.

1 is a schematic perspective view of a varistor according to a first embodiment. It is a schematic sectional drawing of the varistor which concerns on 1st Embodiment. It is the elements on larger scale of the varistor shown in FIG. It is a flowchart which shows the manufacturing process of the varistor which concerns on 1st Embodiment. It is a schematic plan view of the green laminated body which concerns on 1st Embodiment. It is a schematic sectional drawing of the green laminated body and aggregate substrate which concern on 1st Embodiment. It is a figure which shows the formation procedure of the insulating layer of the varistor which concerns on 1st Embodiment. It is a figure which shows the formation procedure of the insulating layer and external electrode of the varistor concerning 1st Embodiment. It is a figure which shows the formation procedure of the external electrode of the varistor which concerns on 1st Embodiment. It is a figure which shows the formation procedure of the external electrode of the varistor which concerns on 1st Embodiment. It is a schematic sectional drawing of the collective substrate with an external electrode which concerns on 1st Embodiment. It is a schematic sectional drawing of the varistor which concerns on 2nd Embodiment. It is a schematic sectional drawing of the green laminated body and aggregate substrate which concern on 2nd Embodiment. It is a schematic sectional drawing of the collective substrate with an external electrode which concerns on 2nd Embodiment. It is a schematic sectional drawing of the varistor which concerns on 3rd Embodiment. It is a schematic sectional drawing of the green laminated body and aggregate substrate which concern on 3rd Embodiment. It is a schematic sectional drawing of the varistor which concerns on 4th Embodiment. It is a schematic sectional drawing of the green laminated body and aggregate substrate which concern on 4th Embodiment. It is a schematic sectional drawing of the varistor which concerns on 5th Embodiment. It is a schematic sectional drawing of the green laminated body and aggregate substrate which concern on 5th Embodiment.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are assigned to the same elements, and duplicate descriptions are omitted.

[First Embodiment]
FIG. 1 is a schematic perspective view of a varistor according to the first embodiment. FIG. 2 is a schematic cross-sectional view of the varistor according to the first embodiment. As shown in FIGS. 1 and 2, the varistor V1 according to the first embodiment includes a substantially rectangular parallelepiped element body 3, insulating layers 4 and 5 formed on upper and lower surfaces of the element body 3, respectively, and a pair of External electrodes 6 and 7 are provided. The element body 3 includes a substantially rectangular parallelepiped heat radiating portion 8 and a first varistor portion 10 and a second varistor portion 20 that sandwich the heat radiating portion 8 from above and below. In addition, let the up-down direction of the element | base_body 3 be a Z direction in an XYZ orthogonal coordinate system.

  The first varistor section 10 includes a varistor element body (first varistor element body) 11, an internal electrode (first internal electrode) 12, and a pair of surface electrodes (first pair of surface electrodes) 13, 14. And. The varistor element body 11 has a substantially rectangular parallelepiped shape, and has a surface (first surface) 11a and a surface (second surface) 11b facing each other in the Z direction. The varistor element body 11 is a laminated body formed by laminating a plurality of varistor layers in the Z direction. Each varistor layer exhibits voltage non-linear characteristics, contains ZnO as a main component, and contains Pr or Bi as a subcomponent. These subcomponents exist in the varistor layer as a single metal or as an oxide. Note that the actual varistor V1 is integrated so that boundaries between the plurality of varistor layers cannot be visually recognized.

  The internal electrode 12 is a substantially rectangular layer, and is arranged at a substantially central portion in the varistor element body 11 so that its main surface is parallel to the first surface 11a. The pair of surface electrodes 13, 14 is a substantially rectangular layer, and is arranged in the X direction on the surface 11 a of the varistor element body 11. The pair of surface electrodes 13 and 14 are arranged away from each other and electrically insulated. And the part by the side of the surface electrode 14 in the surface electrode 13 and the part by the side of the surface electrode 13 in the surface electrode 14 have opposed the internal electrode 12 in the Z direction, respectively.

  The second varistor section 20 includes a varistor element body (second varistor element body) 21, an internal electrode (second internal electrode) 22, and a pair of surface electrodes (second pair of surface electrodes) 23 and 24. And. The varistor element body 21 has a substantially rectangular parallelepiped shape, and includes a surface (third surface) 21a and a surface (fourth surface) 21b facing each other in the Z direction.

  Similar to the varistor element body 11, the varistor element body 21 is a laminated body formed by laminating a plurality of varistor layers in the Z direction. The internal electrode 22 is a substantially rectangular layer, and is disposed at a substantially central portion in the varistor element body 21 so that its main surface is parallel to the surface 21a. The pair of surface electrodes 23 and 24 are substantially rectangular layers and are arranged side by side on the surface 21a of the varistor element body 21 in the X direction. A portion of the surface electrode 23 on the surface electrode 24 side and a portion of the surface electrode 24 on the surface electrode 23 side face the internal electrode 22 in the Z direction, respectively.

  The heat radiating portion 8 has a substantially rectangular parallelepiped shape, and has a surface (fifth surface) 8a and a surface (sixth surface) 8b facing each other in the Z direction. Further, the heat radiating portion 8 has a pair of side surfaces 8c and 8d facing each other in the X direction and a pair of side surfaces 8e and 8f facing each other in the Y direction. The surface 8 a of the heat radiating portion 8 is joined to the surface 11 b of the first varistor portion 10. The surface 8 b of the heat radiating portion 8 is joined to the surface 21 b of the second varistor portion 20.

The heat radiation part 8 is formed of a composite material of metal and metal oxide. As the metal here, for example, Ag, Ag-Pd, Pd, or the like can be used, but Ag is preferably used from the viewpoint of thermal conductivity. Further, as the metal _{oxide, Al 2 O 3, ZnO,} SiO 2, and ZrO ₂ are used. As the Al ₂ O ₃ , for example, a metal oxide particle coated with Ag by electroless plating is used.

  Since such a heat radiation part 8 contains Ag which is a metal, a heat radiation path is established between the surface 8a in contact with the first varistor part 10 and the side surfaces 8c to 8f. Therefore, the heat of the first varistor part 10 is efficiently radiated from the side surfaces 8 c to 8 f of the heat radiating part 8. In addition, the first varistor part 10 and the second varistor part 20 are formed symmetrically with respect to the heat radiating part 8.

  The insulating layer 4 is formed so as to cover the surface 11 a of the varistor element body 11 and the pair of surface electrodes 13 and 14 in the element body 3. The insulating layer 5 is formed so as to cover the surface 21 a of the varistor element body 21 and the pair of surface electrodes 23 and 24 in the element body 3. The insulating layers 4 and 5 are made of polyimide. The insulating layer 4 has openings 4a and 4b at positions corresponding to the pair of surface electrodes 13 and 14, respectively. Thereby, part of the surface of the pair of surface electrodes 13 and 14 is exposed from the insulating layer 4.

  The pair of external electrodes 6 and 7 are arranged on the insulating layer 4 so as to be separated from each other and aligned in the X direction. The external electrode 6 covers the opening 4a of the insulating layer 4, extends into the opening 4a, is in physical contact with the surface electrode 13, and is electrically connected. The external electrode 7 covers the opening 4b of the insulating layer 4, extends into the opening 4b, is in physical contact with the surface electrode 14, and is electrically connected. As shown in FIG. 3, the external electrodes 6 and 7 are formed of four layers of Cr layers 6a and 7a, Cu layers 6b and 7b, Ni layers 6c and 7c, and Au layers 6d and 7d, respectively. The pair of external electrodes 6 and 7 function as connection ends of external elements such as semiconductor light emitting elements.

  Subsequently, a manufacturing process of the above-described varistor V1 will be described. In the manufacturing process of the varistor V1, first, a collective substrate is manufactured. 4, the varistor green sheet preparation step S1, the internal electrode pattern preparation step S2, the surface electrode pattern preparation step S3, and the heat dissipation green sheet preparation step S4, as shown in FIG. The lamination step S5 and the firing step S6 are included. Each step will be described.

  In the varistor green sheet preparation step S1, a predetermined number of varistor green sheets to be varistor layers are prepared. First, ZnO which is the main component of the varistor element bodies 11 and 21 and a metal or oxide such as Pr, Co, Cr, Ca, Si, Bi, etc., which are subcomponents, are mixed at a predetermined ratio to obtain a varistor composition powder. adjust. Next, an organic binder, an organic solvent, an organic plasticizer, and the like are added to the varistor composition powder to obtain a slurry. The slurry is applied on a film and then dried to obtain a varistor green sheet.

  Next, in the internal electrode pattern preparation step S2, a plurality of internal electrode patterns are arrayed on two varistor green sheets. The internal electrode pattern formed on one of the two varistor green sheets becomes the internal electrode 12, and the internal electrode pattern formed on the other varistor green sheet becomes the internal electrode 22. The internal electrode pattern is formed by printing on a varistor green sheet a conductive paste in which an organic binder and an organic solvent are mixed with a metal powder containing Ag particles as a main component and drying.

  Next, in the surface electrode pattern preparation step S3, a plurality of pairs of surface electrode patterns are arrayed on two varistor green sheets. A plurality of pairs of surface electrode patterns formed on one varistor green sheet of the two sheets become surface electrodes 13 and 14, respectively, and a plurality of pairs of surface electrode patterns formed on the other varistor green sheet form surface electrodes 23 and 24, respectively. Become. The surface electrode pattern can be formed in the same manner using the same material as the internal electrode pattern. Next, in a heat radiation green sheet preparation step S4, a predetermined number of heat radiation green sheets constituting the heat radiation portion 8 are prepared. First, Ag powder is mixed with the varistor composition powder forming the varistor layer, and an organic binder, an organic solvent, an organic plasticizer, and the like are added to obtain a slurry. The slurry is applied on a film and then dried to obtain a heat dissipation green sheet. A predetermined number of varistor green sheets, internal electrode patterns, surface electrode patterns, and heat-dissipating green sheets are prepared by the above preparation steps including S1 to S4.

  Subsequently, in the stacking step S5, the varistor green sheet, the internal electrode pattern, the surface electrode pattern, and the heat dissipation green sheet are stacked to form a green stacked body. That is, a varistor green sheet on which nothing is printed, a varistor green sheet on which an internal electrode pattern is formed, a varistor green sheet on which a surface electrode pattern is formed, and a heat-dissipating green sheet are stacked and pressed in a predetermined order, Cut in the stacking direction (Z direction) to form the green stacked body shown in FIG. 5 and FIG.

  FIG. 5 is a schematic plan view of the green laminate, and FIG. 6A is a schematic cross-sectional view of the green laminate. The green laminate 300 contains a plurality of green bodies 30 that become the body 3 after firing. For convenience of illustration, FIG. 5 and FIG. 6 show a green laminated body 300 containing 30 green element bodies arranged in 5 rows in the X direction and 6 rows in the Y direction. The green body 30 is contained.

  The green laminated body 300 includes a heat radiating green portion 308 that becomes the heat radiating portion 8, a first varistor green portion 310 that becomes the first varistor portion 10, and a second varistor green portion 320 that becomes the second varistor portion 20. It has.

  The first varistor green part 310 includes a varistor green sheet in which a plurality of internal electrode patterns 312 are formed, a varistor green sheet in which a plurality of pairs of surface electrode patterns 313 and 314 are formed, and a varistor green in which nothing is formed. It is formed by laminating sheets in a predetermined order in the Z direction. Thus, the first varistor green part 310 has a varistor green layer (first varistor green layer) 311, a plurality of internal electrode patterns 312, and a plurality of pairs of surface electrode patterns 313 and 314.

  The varistor green layer 311 is formed by laminating a plurality of varistor green sheets, and has a main surface (first main surface) 311a and a main surface (second main surface) 311b that face each other in the Z direction. The plurality of internal electrode patterns 312 are arranged in the varistor green layer 311 and arranged in the extending direction (X direction and Y direction) of the varistor green sheet.

  As the varistor green sheet constituting the main surface 311a of the varistor green layer 311, a varistor green sheet on which a plurality of pairs of surface electrode patterns 313 and 314 are formed is used. As a result, a plurality of pairs of surface electrode patterns 313 and 314 are arranged on the main surface 311 a of the varistor green layer 311. The plurality of pairs of surface electrode patterns 313 and 314 are arranged such that one pair of surface electrode patterns 313 and 314 are opposed to one internal electrode pattern 312.

  The second varistor green part 320 includes a varistor green sheet in which a plurality of internal electrode patterns 312 are formed, a varistor green sheet in which a plurality of pairs of surface electrode patterns 313 and 314 are formed, and a varistor green in which nothing is formed. It is formed by laminating sheets in a predetermined order in the Z direction. As a result, the second varistor green part 320 has a varistor green layer (second varistor green layer) 321, a plurality of internal electrode patterns 312, and a plurality of pairs of surface electrode patterns 313 and 314.

  The varistor green layer 321 is configured by laminating a plurality of varistor green sheets, and has a main surface (third main surface) 321a and a main surface (fourth main surface) 321b facing each other in the Z direction. The plurality of internal electrode patterns 312 are arranged in the varistor green layer 321 and are arranged in the extending direction (X direction and Y direction) of the varistor green sheet.

  As the varistor green sheet constituting the main surface 321a of the varistor green layer 321, a varistor green sheet in which a plurality of pairs of surface electrode patterns 313 and 314 are formed is used. As a result, a plurality of pairs of surface electrode patterns 313 and 314 are arranged on the main surface 321 a of the varistor green layer 321. The plurality of pairs of surface electrode patterns 313 and 314 are arranged such that one pair of surface electrode patterns 313 and 314 are opposed to one internal electrode pattern 312.

  The heat dissipating green part 308 is formed by stacking heat dissipating green sheets in the Z direction, and has a main surface (fifth main surface) 308a and a main surface (sixth main surface) 308b facing each other in the Z direction. ing. The main surface 308 a of the heat radiating green portion 308 is joined to the main surface 311 b of the first varistor green portion 310. The main surface 308 b of the heat dissipation green part 308 is joined to the main surface 321 b of the second varistor green part 320. The first varistor green part 310 and the second varistor green part 320 are formed symmetrically with respect to the heat dissipation green part 308.

Next, in the firing step S6, the obtained green laminate 300 is subjected to binder removal processing. For example, the binder removal treatment is performed by performing a heat treatment at a temperature of 180 ° C. to 400 ° C. for about 0.5 hours to 24 hours. After the binder removal treatment is performed on the green laminated body 300, the aggregate substrate 31 shown in FIG. 6B is formed by firing at a temperature of 800 ° C. or higher in an O ₂ atmosphere.

  The collective substrate 31 includes a heat dissipation layer 9 formed by firing the heat dissipation green portion 308, a first varistor portion 19 formed by firing the first varistor green portion 310, and a second varistor green portion 320. And a second varistor portion 29 formed by firing.

  The first varistor portion 19 includes a varistor element layer (first varistor element layer) 18 formed by firing the varistor green layer 311 and a plurality of internal electrode patterns 312 formed by firing. An internal electrode (a plurality of first internal electrodes) 12 and a plurality of pairs of surface electrodes 13 and 14 formed by firing a plurality of pairs of surface electrode patterns 313 and 314 are provided. The varistor element layer 18 includes a main surface (first main surface) 18a formed by baking the main surface 311a of the varistor green layer 311, and a main surface formed by baking the main surface 311b of the varistor green layer 311. And a surface (second main surface) 18b.

  The second varistor section 29 is formed by firing a varistor element layer (second varistor element layer) 28 formed by firing the varistor green layer 321 and a plurality of internal electrode patterns 312. A plurality of internal electrodes (a plurality of second internal electrodes) 22 and surface electrodes 23 and 24 formed by firing the surface electrode pattern 313 are provided. The varistor element layer 28 includes a main surface (third main surface) 28a formed by firing the main surface 321a of the varistor green layer 321 and a main surface formed by firing the main surface 321b of the varistor green layer 321. And a surface (fourth main surface) 28b.

  The heat dissipation layer 9 includes a main surface (fifth main surface) 9a formed by firing the main surface 308a of the heat dissipating green portion 308 and a main surface formed by firing the main surface 308b of the heat dissipating green portion 308 ( 6th main surface) 9b. The heat dissipation green sheet and the varistor green sheet contain the common component ZnO, and the binder removal and firing are performed in a state where the main surface 308a of the heat dissipation green portion 308 and the main surface 311b of the first varistor green portion 310 are joined. As a result, the main surface 9a of the heat dissipation layer 9 and the main surface 18b of the first varistor portion 19 are more firmly bonded. Similarly, binder removal and firing are performed in a state where the main surface 308b of the heat radiating green portion 308 and the main surface 321b of the second varistor green portion 320 are joined together, whereby the main surface 9b of the heat radiating layer 9 and the second surface The main surface 28b of the varistor portion 29 is more firmly bonded. The first varistor part 19 and the second varistor part 29 are formed symmetrically with respect to the heat dissipation layer 9.

  Although the shrinkage rate during firing of the heat dissipating green portion 308 is different from the shrinkage rate during firing of the first and second varistor green portions 310 and 320, the first varistor green portion 310 is formed on the main surface 308a of the heat dissipating green portion 308. The second varistor green part 320 is in contact with the main surface 308b of the heat radiating green part 308, and the heat radiating green part 308 is sandwiched between the first varistor green part 310 and the second varistor green part 320. The flat aggregate substrate 31 can be formed by preventing the occurrence of warpage during firing.

  After the collective substrate 31 is formed by the above steps, the insulating layer forming step S7 and the external electrode forming step S7 are performed to manufacture the collective substrate with external electrodes. The insulating layer forming step S7 and the external electrode forming step S8 will be described with reference to FIGS. 7 to 10, for convenience of the drawing, a portion corresponding to one element body 3 of the collective substrate 31 is illustrated, but actually, the same processing is performed on the entire collective substrate 31.

  First, in the insulating layer forming step S7, insulating layers are respectively formed on the main surface 18a of the first varistor part 19 and the main surface 28a of the second varistor part 29 shown in FIG. First, as shown in FIG. 7B, a raw material solution of photosensitive polyimide is applied to the main surface 18a of the first varistor part 19 and the main surface 28a of the second varistor part 29 by spin coating, and then temporarily cured. Drying is performed to form temporarily cured polyimide layers 41 and 42.

  Next, as shown in FIG.7 (c), in order to form an opening part in the polyimide layer 41 formed in the 1st surface 18a, the glass negative mask 43 is covered and it exposes. Subsequently, as shown in FIG. 8A, the whole substrate 31 is immersed in a Na-based aqueous solution 44 and development is performed, whereby openings 41a and 41b are formed. Part of the surface electrodes 13 and 14 is exposed from the openings 41a and 41b. The openings 41a and 41b correspond to the openings 4a and 4b of the varistor V1.

  Thereafter, after cleaning with pure water, the polyimide layers 41 and 42 are subjected to main curing and drying, whereby insulating layers 45 and 46 are formed as shown in FIG. As described above, the insulating layers 45 and 46 to be the insulating layers 4 and 5 are formed.

  Subsequently, in the external electrode formation step S8, a plurality of pairs of external electrodes 6 and 7 are formed. First, as shown in FIG. 8B, a Cr layer 47 that covers the insulating layer 45 and part of the surface electrodes 13 and 14 exposed from the openings 45a and 45b of the insulating layer 45 is formed by sputtering. . Subsequently, a Cu layer 48 is formed on the Cr layer 47 by sputtering. Then, as shown in FIG. 8C, a dry film 49 is attached on the Cu layer 48.

  As shown in FIG. 9A, the mask 50 corresponding to the shape of the external electrodes 6 and 7 is placed on the dry film 49 for exposure. Subsequently, as shown in FIG. 9B, the entire substrate 31 is immersed in the developer 51 for development, whereby the dry film 49 is formed in the shape of the external electrodes 6 and 7. After the development, as shown in FIG. 9C, the Cu layers 6b and 7b are formed by immersing the collective substrate 31 in the etching solution 59 and etching the Cu layer 48, and are washed with pure water.

  Subsequently, as shown in FIG. 10A, the entire substrate 31 is immersed in a peeling solution 53 to peel off the dry film 49. Subsequently, as shown in FIG. 10B, the Cr layers 6 a and 7 a are formed by immersing in the etching solution 54 and etching the Cr layer 47. Then, it is made to dry after washing with pure water.

  Subsequently, Ni plating is performed on the Cu layers 6b and 7b to form Ni layers 6c and 7c. Thereafter, the Ni layers 6c and 7c are immersed in a plating solution 55 to perform flash plating, thereby forming Au layers 6d and 7d. Thereby, the external electrodes 6 and 7 constituted by the Cr layers 6a and 7a, the Cu layers 6b and 7b, the Ni layers 6c and 7c, and the Au layers 6d and 7d are completed.

  Through the above steps, the collective substrate 32 with external electrodes shown in FIG. 11 is completed. The collective substrate 32 with external electrodes includes the collective substrate 32, insulating layers 45 and 46, and a plurality of pairs of external electrodes 6 and 7. The insulating layers 45 and 46 correspond to the insulating layers 4 and 5, respectively. By cutting the collective substrate 32 with external electrodes, a plurality of varistors V1 are completed (cutting step S8).

  In the varistor V1 formed in this way, the heat radiating part 8 contains ZnO which is the main component of the varistor element bodies 11 and 21. Further, during firing, Ag contained in the heat radiating portion 8 is in the ZnO grain boundaries in the varistor element bodies 11 and 21 in the vicinity of the interface between the surface 11b and the surface 8a and in the vicinity of the interface between the surface 21b and the surface 8b. Spread. Thereby, the 1st varistor part 10 and the thermal radiation part 8 are joined firmly, and the 2nd varistor part 20 and the thermal radiation part 8 are joined firmly.

Therefore, in the varistor V1, cracks are generated between the first varistor part 10 and the heat radiating part 8 and between the second varistor part 20 and the heat radiating part 8 during firing (or during binder removal). There is almost nothing, and the bonding strength between the first varistor part 10 and the heat radiating part 8 and the bonding strength between the second varistor part 20 and the heat radiating part 8 are sufficiently ensured. Therefore, the heat transferred from the external element to the first varistor part 10 through the external electrodes 6 and 7 is spread from the surface 8a to the side surfaces 8c to 8f in the heat radiation part 8 by the coating part of Ag particles and Al ₂ O _3. Heat is efficiently radiated through the formed conduction path.

  Further, in the step of manufacturing the varistor V1, the first and second varistor portions 10 and 20 and the heat radiating portion 8 are simultaneously fired. Thereby, simplification of a manufacturing process is implement | achieved and it contributes to the improvement of the manufacturing efficiency of the varistor V1, and cost reduction.

  Further, although the shrinkage rate during firing of the heat dissipating green part 308 is different from the shrinkage rate during firing of the first and second varistor green parts 310 and 320, the first varistor green part is formed on the main surface 308a of the heat dissipating green part 308. 310, the second varistor green part 320 contacts the main surface 308 b of the heat dissipation green part 308, and the heat dissipation green part 308 is sandwiched between the first varistor green part 310 and the second varistor green part 320. Therefore, it is possible to prevent the occurrence of warpage during firing and form the planar aggregate substrate 31. Since the external electrodes 6 and 7 are formed on the flat aggregate substrate and cut to obtain individual varistors V1, a plurality of varistors V1 having good heat dissipation efficiency can be easily manufactured.

[Second Embodiment]
A varistor according to a second embodiment of the present invention will be described. FIG. 12 is a schematic sectional view showing a varistor according to the second embodiment of the present invention. The varistor V2 shown in FIG. 12 does not include a surface electrode, and is different from the varistor V1 according to the first embodiment in the configuration of the internal electrode. The varistor V2 includes an element body 3A instead of the element body 3, and the element body 3A includes first and second varistor portions 60 and 70 instead of the first and second varistor portions 10 and 20. ing.

  The first varistor part 60 includes a substantially rectangular parallelepiped varistor element (first varistor element) 61 and a pair of internal electrodes (first and second internal electrodes) 62 facing each other in the varistor element 61. , 63 and through conductors 64, 65. The varistor element body 61 includes a surface (first surface) 61a and a surface (second surface) 61b that face each other in the Z direction. The insulating layer 4 is formed on the surface 61 a, and the surface 61 b is joined to the surface 8 a of the heat radiating portion 8. The internal electrodes 62 and 63 are offset in the X direction and partly face each other in the Z direction.

  The through electrode 64 extends in the Z direction, one end is physically and electrically connected to the internal electrode 62, and the other end is exposed from the surface 61a. The other end of the through electrode 64 is located in the opening 4 a of the insulating layer 4 and is physically and electrically connected to the external electrode 6. The through electrode 65 extends in the Z direction, one end is physically and electrically connected to the internal electrode 63, and the other end is exposed from the surface 61a. The other end of the through electrode 65 is located in the opening 4 b of the insulating layer 4 and is physically and electrically connected to the external electrode 7. That is, the internal electrode 62 is electrically connected to the external electrode 6 by the through electrode 64, and the internal electrode 63 is electrically connected to the external electrode 7 by the through electrode 65.

  The second varistor part 70 includes a substantially rectangular parallelepiped varistor element (second varistor element) 71 and a pair of internal electrodes (third and fourth internal electrodes) 72 facing each other in the varistor element 71. , 73 and through conductors 74, 75. The varistor element body 71 includes a surface (third surface) 71a and a surface (fourth surface) 71b facing each other in the Z direction. The insulating layer 5 is formed on the surface 71 a, and the surface 71 b is joined to the surface 8 b of the heat radiating portion 8. The internal electrodes 72 and 73 are offset in the X direction and partly face each other in the Z direction.

  The through electrode 74 extends in the Z direction, one end is physically and electrically connected to the internal electrode 72, and the other end is exposed from the surface 71a. The other end of the through electrode 74 is covered with the insulating layer 5. The through electrode 75 extends in the Z direction, one end is physically and electrically connected to the internal electrode 73, and the other end is exposed from the surface 71a. The other end of the through electrode 75 is covered with the insulating layer 5. The first varistor part 60 and the second varistor part 70 are formed symmetrically with respect to the heat radiating part 8.

  A method for manufacturing the varistor V2 will be described. The varistor V2 is manufactured by the same manufacturing method as the varistor V1 according to the first embodiment, but the configuration of the internal electrodes 62, 63, 72, 73 of the first and second varistor portions 60, 70 is different. The green laminate formed in the lamination step S5 and the aggregate substrate formed in the firing step S6 are partially different. This point will be described with reference to FIGS.

  FIG. 13A is a schematic cross-sectional view of a green laminate. The green laminated body 300A of the second embodiment includes a plurality of green element bodies 30A. The green laminated body 300A includes a heat radiating green portion 308 that becomes the heat radiating portion 8, a first varistor green portion 360 that becomes the first varistor portion 60, and a second varistor green portion 370 that becomes the second varistor portion 70. And.

  The first varistor green part 360 includes a varistor green sheet on which the internal electrode pattern 362 is formed, a varistor green sheet on which the internal electrode pattern 363 is formed, and a varistor green sheet on which nothing is formed in a predetermined order in the Z direction. It is formed by laminating.

  In the varistor green sheet, a through hole is previously formed at a position corresponding to the through conductor, and the through hole is filled with a conductive paste. The through electrode patterns 364 and 365 can be formed by laminating not only the internal electrode patterns 362 and 363 but also varistor green sheets filled with a conductive paste in the through holes.

  Accordingly, the first varistor green part 360 includes a varistor green layer (first varistor green layer) 361, a plurality of internal electrode patterns 362, a plurality of internal electrode patterns 363, a plurality of through electrode patterns 364, A plurality of through electrode patterns 365.

  The varistor green layer 361 is configured by laminating a plurality of varistor green sheets, and has a main surface (first main surface) 361a and a main surface (second main surface) 361b facing each other in the Z direction. The plurality of internal electrode patterns 362 are arranged in the varistor green layer 311 and arranged in the extending direction (X direction and Y direction) of the varistor green sheet. The plurality of internal electrode patterns 363 are arranged to face the plurality of internal electrode patterns 362 in the Z direction, respectively.

  The plurality of through-electrode patterns 364 extend in the Z direction, one end is in physical contact with each of the plurality of internal electrode patterns 362, and the other end is exposed from the main surface 361a. The plurality of through electrode patterns 365 extend in the Z direction, one end physically contacts the plurality of internal electrode patterns 363, and the other end is exposed from the main surface 361a.

  The second varistor green part 370 includes a varistor green layer (second varistor green layer) 371, a plurality of internal electrode patterns 372, a plurality of internal electrode patterns 373, a plurality of through electrode patterns 374, and a plurality of through holes. An electrode pattern 375. The varistor green layer 371 has a main surface (third main surface) 371a and a main surface (fourth main surface) 371b that face each other in the Z direction. The plurality of internal electrode patterns 372 are arranged in the varistor green layer 311 and arranged in the extending direction (X direction and Y direction) of the varistor green sheet. The plurality of internal electrode patterns 373 are arranged to face the plurality of internal electrode patterns 362 in the Z direction, respectively.

  The plurality of through-electrode patterns 374 extend in the Z direction, one end is in physical contact with each of the plurality of internal electrode patterns 372, and the other end is exposed from the main surface 371a. The plurality of through-electrode patterns 375 extend in the Z direction, one end is in physical contact with each of the plurality of internal electrode patterns 373, and the other end is exposed from the main surface 371a.

  The main surface 308a of the heat dissipation green portion 308 is joined to the surface 371b of the first varistor green portion 370. The main surface 308b of the heat radiating green portion 308 is joined to the surface 371b of the second varistor green portion 370. The first varistor green part 370 and the second varistor green part 370 are formed symmetrically with respect to the heat dissipation green part 308.

  Subsequently, the collective substrate 31A according to the second embodiment will be described with reference to FIG. The collective substrate 31A includes a plurality of element bodies 3A. The aggregate substrate 31A includes a heat dissipation layer 9 formed by firing the heat dissipation green portion 308, a first varistor portion 69 formed by firing the first varistor green portion 360, and a second varistor green portion. 370 includes a second varistor portion 79 formed by firing.

  The first varistor portion 69 includes a varistor element layer (first varistor element layer) 68 formed by firing the varistor green layer 361 and a plurality of internal electrode patterns 362 formed by firing. An internal electrode (a plurality of first internal electrodes) 62, a plurality of internal electrodes (a plurality of third internal electrodes) 63 formed by firing a plurality of internal electrode patterns 363, and a plurality of through conductor patterns 364 A plurality of through conductors 64 formed by firing and a plurality of through conductors 65 formed by firing a plurality of through conductor patterns 365 are provided. The varistor element layer 68 includes a main surface (first main surface) 68a formed by baking the main surface 361a of the varistor green layer 361 and a surface formed by baking the main surface 361b of the varistor green layer 361. (Second main surface) 68b.

  The second varistor part 79 includes a varistor element layer (second varistor element layer) 78 formed by firing the varistor green layer 371 and a plurality of internal electrode patterns 372 formed by firing. An internal electrode (a plurality of second internal electrodes) 72, a plurality of internal electrodes (a plurality of fourth internal electrodes) 73 formed by firing a plurality of surface electrode patterns 373, and a plurality of through conductor patterns 374 A plurality of through conductors 74 formed by firing and a plurality of through conductors 75 formed by firing a plurality of through conductor patterns 375 are provided. The varistor element layer 78 includes a main surface (third main surface) 78a formed by baking the main surface 371a of the varistor green layer 371 and a surface formed by baking the surface 371b of the varistor green layer 371 ( 4th main surface) 78b.

  The insulating layers 45 and 46 are formed on the collective substrate 31A thus formed, and a plurality of pairs of external electrodes 6 and 7 are formed, whereby the collective substrate 32A with external electrodes shown in FIG. 14 is completed. The plurality of pairs of external electrodes 6 and 7 are physically and electrically connected to the through conductors 64 and 65, respectively. By cutting the collective substrate 32A with external electrodes, a plurality of varistors V2 are completed.

  Also in this varistor V2, the varistor element bodies 61 and 71 are mainly composed of ZnO, and the heat dissipating part 8 is composed of Ag which is a metal and a metal oxide containing ZnO which is the main component of the varistor element bodies 61 and 71. It is made of a composite material. Therefore, as in the first embodiment, the bonding strength between the first varistor part 60 and the heat radiating part 8 is sufficiently secured, and the heat transmitted from the external element to the varistor part 60 via the external electrodes 6 and 7 is Heat is efficiently radiated through a conduction path formed from the surface 8a to the side surfaces 8c to 8f in the heat radiating portion 8. In addition, the bonding strength between the second varistor part 70 and the heat dissipation part 8 is sufficiently ensured.

  Furthermore, the shrinkage rate during firing of the heat dissipating green part 308 is different from the shrinkage rate during firing of the first and second varistor green parts 360 and 370, but the first varistor is formed on the main surface 308a of the heat dissipating green part 308. The green part 360 is in contact, the second varistor green part 370 is in contact with the main surface 308 b of the heat dissipation green part 308, and the heat dissipation green part 308 is connected to the first varistor green part 360 and the second varistor green part 370. Since they are sandwiched, it is possible to prevent the occurrence of warpage during firing and form the planar aggregate substrate 31A. Since the external electrodes 6 and 7 are formed on the flat aggregate substrate and cut to obtain individual varistors V2, a plurality of varistors V2 having good heat dissipation efficiency can be easily manufactured.

[Third Embodiment]
A varistor according to a third embodiment of the present invention will be described. FIG. 15 is a schematic sectional view showing a varistor according to the third embodiment of the present invention. The varistor V3 shown in FIG. 15 includes an element body 3B, insulating layers 4 and 5, a pair of external electrodes 6 and 7, and a pair of external electrodes 76 and 77. The element body 3 </ b> B includes a first varistor part 60, a second varistor part 70, and a heat dissipation part 80.

  The first varistor section 60 includes through conductors 85 and 86 in addition to the internal electrodes 62 and 63 and the through conductors 64 and 65 described above. The through conductor 85 extends in the Z direction, one end is physically and electrically connected to the internal electrode 62, and the other end is exposed from the surface 61b. The through conductor 86 extends in the Z direction, one end is physically and electrically connected to the internal electrode 63, and the other end is exposed from the surface 61b.

  The second varistor part 70 includes through conductors 87 and 88 in addition to the internal electrodes 72 and 73 and the through conductors 74 and 75 described above. The through conductor 87 extends in the Z direction, one end is physically and electrically connected to the internal electrode 72, and the other end is exposed from the surface 71b. The through conductor 88 extends in the Z direction, one end is physically and electrically connected to the internal electrode 73, and the other end is exposed from the surface 71b.

  The insulating layer 5 has openings 5 a and 5 b at positions corresponding to the through conductors 74 and 75. The external electrode 76 is formed so as to cover the opening 5 a and is physically and electrically connected to the through conductor 74. The external electrode 77 is formed so as to cover the opening 5 b and is physically and electrically connected to the through conductor 75.

  The heat radiation part 80 includes a surface (fifth surface) 80a and a surface (sixth surface) 80b that face each other in the Z direction. The heat radiating part 80 is formed of the same material as that of the heat radiating part 8. The heat radiating portion 80 includes two through conductors 81 and 82 that penetrate the surface 80a and the surface 80b, and electrically insulating layers 83 and 84 that are formed around the through conductors 81 and 82, respectively. Yes.

  The through conductor 81 extends in the Z direction, one end is physically and electrically connected to the through conductor 85, and the other end is physically and electrically connected to the through conductor 87. As a result, the external electrode 6 and the external electrode 76 are electrically connected via the through conductors 64, 85, 81, 87, 74. The through conductor 82 extends in the Z direction, one end is physically and electrically connected to the through conductor 86, and the other end is physically and electrically connected to the through conductor 88. As a result, the external electrode 7 and the external electrode 77 are electrically connected via the through conductors 65, 86, 82, 88 and 75. Note that the first varistor part 60 and the second varistor part 70 have a symmetrical configuration with respect to the heat radiating part 8.

  In the varistor V3, when an external element is connected to the external electrodes 6 and 7, not only the first varistor part 60 but also the second varistor part 70 is connected in parallel to the electronic element. The varistor part 70 also exhibits a function of protecting the electronic element from an ESD surge. In the varistor V3, the external electrodes 6 and 7 may be connection ends of external elements, and the external electrodes 76 and 77 may be connection ends of external elements. Furthermore, the external electrodes 6 and 7 may be connection ends of external elements, and the external electrodes 76 and 77 may be connection ends of the substrate.

  A method for manufacturing the varistor V3 will be described. The varistor V3 is manufactured by the same manufacturing method as the varistor V2 according to the second embodiment. However, since the heat dissipating part 80 includes the through conductors 81 and 82 and the layers 83 and 84, the green lamination formed in the lamination step S5 is performed. The structure of the aggregate substrate formed in the body and firing step S6 is partially different. This point will be described with reference to FIG.

  FIG. 16A is a schematic cross-sectional view of a green laminate. The green laminated body 300B of the third embodiment includes a plurality of green element bodies 30B. The green laminated body 300 </ b> B includes a heat radiating green part 380 that becomes the heat radiating part 80, a first varistor green part 360, and a second varistor green part 370.

  The heat dissipation green part 380 is formed by stacking heat dissipation green sheets in the Z direction. A through hole is formed in the heat dissipation green sheet in advance, and the through hole is filled with an insulating material constituting the layers 383 and 384. Thereafter, a through hole is formed in the center of the portion filled with the insulating material, and this through hole is filled with a conductive paste. By laminating such heat radiation green sheets, a plurality of through electrode patterns 381 and 382 covered with layers 383 and 384 are formed.

  The heat dissipation green portion 380 has a main surface (fifth main surface) 380a and a main surface (sixth main surface) 380b that face each other in the Z direction. The surface 380a of the heat dissipation green portion 380 is joined to the surface 361b of the first varistor green portion 360. The through electrode patterns 381 and 382 of the heat dissipation green part 380 and the through electrode patterns 385 and 386 of the first varistor green part 360 are physically connected to each other. Further, the surface 380b of the heat radiating green portion 380 is joined to the surface 371b of the second varistor green portion 370. The through electrode patterns 381 and 382 of the heat dissipation green part 380 and the through electrode patterns 387 and 388 of the second varistor green part 370 are physically connected to each other. Note that the first varistor green part 360 and the second varistor green part 370 are formed symmetrically with respect to the heat dissipation green part 380.

  Subsequently, the collective substrate 31B according to the third embodiment will be described with reference to FIG. The collective substrate 31B includes a plurality of element bodies 3B. The collective substrate 31B includes a heat dissipation layer 89 formed by firing the heat dissipation green portion 380, a first varistor portion 69, and a second varistor portion 79. The first varistor part 69 and the second varistor part 79 are formed symmetrically with respect to the heat dissipation layer 89.

  The insulating layers 45 and 46 are formed on the aggregate substrate 31B thus formed, and a plurality of pairs of external electrodes 6 and 7 and a plurality of pairs of external electrodes 76 and 77 are formed, thereby completing the aggregate substrate with external electrodes. A plurality of varistors V3 are completed by cutting the collective substrate with external electrodes.

  Also in this varistor V3, the varistor element bodies 61 and 71 are mainly composed of ZnO, and the heat radiating portion 8 is composed of Ag, which is a metal, and a metal oxide containing ZnO, which is the main component of the varistor element bodies 61, 71. It is made of a composite material. Therefore, the bonding strength between the first varistor part 60 and the heat radiating part 80 is sufficiently ensured, and the heat transferred from the external element to the varistor part 60 through the external electrodes 6 and 7 is exposed from the surface 80a of the heat radiating part 80. The heat is efficiently radiated through the conduction path formed over the side surface. Further, the bonding strength between the second varistor part 70 and the heat radiating part 80 is sufficiently ensured, and the heat transferred from the external element to the varistor part 70 through the external electrodes 76 and 77 is exposed from the surface 80b of the heat radiating part 80. The heat is efficiently radiated through the conduction path formed over the side surface.

  Further, the shrinkage rate during firing of the heat dissipating green part 380 and the shrinkage rate during firing of the first and second varistor green parts 360 and 370 are different, but the first varistor green part is formed on the main surface 380a of the heat dissipating green part 380. 360 contacts, the second varistor green part 370 contacts the main surface 380b of the heat dissipation green part 380, and the heat dissipation green part 380 is sandwiched between the first varistor green part 360 and the second varistor green part 370. Therefore, it is possible to prevent the occurrence of warpage during firing and form the planar aggregate substrate 31B. Since the external electrodes 6, 7, 76 and 77 are formed on the flat aggregate substrate and cut to obtain individual varistors V3, a plurality of varistors V3 having good heat dissipation efficiency can be easily manufactured.

[Fourth Embodiment]
A varistor according to a fourth embodiment of the present invention will be described. FIG. 17 is a schematic sectional view showing a varistor according to the fourth embodiment of the present invention. The varistor V4 shown in FIG. 17 differs from the varistor V1 in the configuration of the internal electrodes of the first and second varistor parts. The varistor V4 includes an element body 3C instead of the element body 3, and the element body 3C includes a first varistor part 90, a second varistor part 100, and a heat dissipation part 8.

  The first varistor section 90 includes a varistor element body (first varistor element body) 91, internal electrodes 92a to 94a, 92b to 94b, and 95 to 97, a pair of surface electrodes 98a and 98b, a through conductor 99a, 99b. The varistor element body 91 has a surface (first surface) 91a and a surface (second surface) 91b that face each other in the Z direction.

  The internal electrodes 92a to 94a, 92b to 94b, and 95 to 97 are arranged in the varistor element body 91. The internal electrodes 92a and 92b are arranged side by side in the X direction. The internal electrode 95 is disposed on the upper side of the internal electrodes 92a and 92b so that the portions near the center of the internal electrodes 92a and 92b and the internal electrode 95 face each other in the Z direction with the varistor layer interposed therebetween. Similarly, the internal electrodes 93a and 93b and the internal electrodes 94a and 94b are arranged side by side in the X direction, and the internal electrodes 93a and 93b are arranged on the internal electrode 95 via a varistor layer. The internal electrode 96 is disposed via a varistor layer, the internal electrodes 94a and 94b are disposed above the varistor layer, and the internal electrode 97 is disposed thereon.

  The surface electrodes 98 a and 98 b are formed on the surface 91 a of the varistor element body 91, and the central portion of each of the surface electrodes 98 a and 98 b faces the internal electrode 97. When viewed from the Z direction, the internal electrodes 92a to 94a and the surface electrode 98a overlap each other, the internal electrodes 92b to 94b and the surface electrode 98b overlap each other, and the internal electrodes 95 to 97 overlap each other.

  Each of the internal electrodes 92a to 94a and the surface electrode 98a is physically and electrically connected to the through electrode 99a extending in the Z direction. Each of the internal electrodes 92b to 94b and the surface electrode 98b is physically and electrically connected to the through electrode 99b extending in the Z direction. Since the surface electrodes 98a and 98b are electrically connected to the external electrodes 6 and 7, respectively, the internal electrodes 92a to 94a and the internal electrodes 92b to 94b are electrically connected to the external electrodes 6 and 7, respectively. It will be.

  The second varistor section 100 includes a varistor element body 101, internal electrodes 102a to 104a, 102b to 104b, 105 to 107, a pair of surface electrodes 108a and 108b, and through conductors 109a and 109b. The varistor element body 101 has a surface (second surface) 101a and a surface (fourth surface) 101b that face each other in the Z direction.

  The internal electrodes 102 a to 104 a, 102 b to 104 b, and 105 to 107 are arranged in the varistor element body 101. The internal electrodes 102a and 102b are arranged side by side in the X direction. The internal electrode 105 is disposed below the internal electrodes 92a and 92b so that the portions near the center of the internal electrodes 102a and 102b and the internal electrode 105 face each other in the Z direction with the varistor layer interposed therebetween. Similarly, the internal electrodes 103a and 103b and the internal electrodes 104a and 104b are arranged side by side in the X direction, and the internal electrodes 103a and 103b are arranged below the internal electrode 105 via a varistor layer. The internal electrode 106 is disposed via a varistor layer, the internal electrodes 104a and 104b are disposed below the varistor layer, and the internal electrode 107 is disposed below the internal electrode 104a.

  The surface electrodes 108 a and 108 b are formed on the surface 101 a of the varistor element body 101, and the central portion of each of the surface electrodes 108 a and 108 b faces the internal electrode 107. When viewed from the Z direction, the internal electrodes 102a to 104a and the surface electrode 108a overlap each other, the internal electrodes 102b to 104b and the surface electrode 108b overlap each other, and the internal electrodes 105 to 107 overlap each other.

  Each of the internal electrodes 102a to 104a and the surface electrode 108a is physically and electrically connected to the through electrode 109a extending in the Z direction. Each of the internal electrodes 102b to 104b and the surface electrode 108b is physically and electrically connected to the through electrode 109b extending in the Z direction.

  The surface 91b of the first varistor part 90 is joined to the surface 8a of the heat dissipation part 8, and the surface 101b of the second varistor part 100 is joined to the surface 8b of the heat dissipation part 8. The first varistor part 90 and the second varistor part 100 are formed symmetrically with respect to the heat radiating part 8.

  A method for manufacturing the varistor V4 will be described. The varistor V4 is manufactured by the same manufacturing method as the varistor V1 according to the first embodiment. However, since the configuration of the internal electrodes in the first and second varistor portions is different, the green laminate formed in the lamination step S5. The structure of the aggregate substrate formed in the firing step S6 is partially different. This point will be described with reference to FIG.

  FIG. 18A is a schematic cross-sectional view of a green laminate. The green laminated body 300C of the fourth embodiment includes a plurality of green element bodies 30C. The green laminated body 300 </ b> C includes a heat radiating green portion 308, a first varistor green portion 390, and a second varistor green portion 400.

  The first varistor green portion 390 includes a varistor green layer (first varistor green layer) 391, a plurality of internal electrode patterns 392a to 394a, 392b to 394b, 395 to 397, and a plurality of pairs of surface electrode patterns 398a and 398b. And a plurality of through conductor patterns 399a and 399b. The plurality of internal electrode patterns 392a to 394a, 392b to 394b, and 395 to 397 correspond to the internal electrodes 92a to 94a, 92b to 94b, and 95 to 97, respectively. The plurality of pairs of surface electrode patterns 398a and 398b correspond to the pair of surface electrodes 98a and 98b. The plurality of through conductor patterns 399a and 399b correspond to the through conductors 99a and 99b.

  A varistor green sheet in which a plurality of internal electrode patterns 392a to 394a, 392b to 394b, 395 to 397, a plurality of pairs of surface electrode patterns 398a and 398b, and through holes filled with a conductive paste are formed The first varistor green part 390 is formed by stacking in this order. The varistor green layer 391 includes a main surface (first main surface) 391a and a main surface (second main surface) 391b that face each other in the Z direction. The main surface 391b is joined to the main surface 308a of the heat dissipation green portion 308.

  The second varistor green part 400 includes a varistor green layer (second varistor green layer) 401, a plurality of internal electrode patterns 402a to 404a, 402b to 404b, and 405 to 407, and a plurality of pairs of surface electrode patterns 408a and 408b. And a plurality of through conductor patterns 409a and 409b. The plurality of internal electrode patterns 402a to 404a, 402b to 404b, and 405 to 407 correspond to the internal electrodes 102a to 104a, 102b to 104b, and 105 to 107, respectively. The plurality of pairs of surface electrode patterns 408a and 408b correspond to the pair of surface electrodes 108a and 108b. The plurality of through conductor patterns 409a and 409b correspond to the through conductors 109a and 109b.

  A varistor green sheet having a plurality of internal electrode patterns 402a to 404a, 402b to 404b, 405 to 407, a plurality of pairs of surface electrode patterns 408a and 408b, and a through hole filled with a conductive paste, respectively, is predetermined. The second varistor green part 400 is formed by stacking in this order. The varistor green layer 401 includes a main surface (third main surface) 401a and a main surface (fourth main surface) 401b facing each other in the Z direction. The main surface 401b is joined to the main surface 308a of the heat dissipation green portion 308. The first varistor green part 390 and the second varistor green part 400 are formed symmetrically with respect to the heat dissipation green part 308.

  Subsequently, a collective substrate 31C according to the fourth embodiment will be described with reference to FIG. The collective substrate 31C includes a plurality of element bodies 3C. The aggregate substrate 31C includes a heat dissipation layer 9, a first varistor part 298 formed by firing the first varistor green part 390, and a second formed by firing the second varistor green part 400. And a varistor portion 299. The collective substrate 31 </ b> C has a symmetric configuration with respect to the heat dissipation layer 9.

  The insulating layers 45 and 46 are formed on the collective substrate 31C thus formed, and a plurality of pairs of external electrodes 6 and 7 are formed, thereby completing the collective substrate with external electrodes. A plurality of varistors V4 are completed by cutting the collective substrate with external electrodes.

  Also in this varistor V4, the varistor element bodies 91 and 101 are mainly composed of ZnO, and the heat radiating portion 8 is composed of Ag, which is a metal, and a metal oxide including ZnO, which is the main component of the varistor element bodies 91, 101. It is made of a composite material. Therefore, as in the first embodiment, the bonding strength between the first varistor part 90 and the heat radiating part 8 is sufficiently secured, and is transmitted from the external element to the first varistor part 90 via the external electrodes 6 and 7. The heat is efficiently radiated through a conduction path formed over the side surface exposed from the surface 80a of the heat radiating portion 8. Further, the bonding strength between the second varistor part 100 and the heat radiating part 8 is sufficiently secured.

  Further, the shrinkage rate during firing of the heat dissipating green part 308 is different from the shrinkage rate during firing of the first and second varistor green parts 390 and 400, but the first varistor green part is formed on the main surface 308a of the heat dissipating green part 308. 390 is in contact, the second varistor green part 400 is in contact with the main surface 308b of the heat dissipation green part 308, and the heat dissipation green part 308 is sandwiched between the first varistor green part 390 and the second varistor green part 400. Therefore, it is possible to prevent the occurrence of warpage during firing and form the planar aggregate substrate 31C. Since the external electrodes 6 and 7 are formed on the flat aggregate substrate and cut to obtain individual varistors V4, a plurality of varistors V4 having good heat dissipation efficiency can be easily manufactured.

[Fifth Embodiment]
A varistor according to a fifth embodiment of the present invention will be described. FIG. 19 is a schematic sectional view showing a varistor according to the fifth embodiment of the present invention. A varistor V5 shown in FIG. 19 is different from the varistor V2 according to the second embodiment in that a plurality of pairs of internal electrodes (three pairs in this embodiment) are formed. The varistor V5 includes an element body 3D instead of the element body 3, and the element body 3D includes first and second varistor portions 110 and 120 instead of the first and second varistor portions 10 and 20. ing.

  The first varistor section 110 includes a varistor element body (first varistor element body) 111, three pairs of internal electrodes (first and second internal electrodes) 112, 113 facing each other in the varistor element body 111, and And through conductors 114 and 115. The varistor element body 111 includes a surface (first surface) 111a and a surface (second surface) 111b facing each other in the Z direction. The surface 111b is joined to the surface 8a of the heat dissipation part 8. The internal electrodes 112 and 113 are offset from each other in the X direction, and some of them are opposed to each other in the Z direction. The internal electrodes 112 and the internal electrodes 113 are alternately stacked via varistor layers.

  The through electrode 114 extends in the Z direction, is physically and electrically connected to the three internal electrodes 112, and the tip is exposed from the surface 111a. The tip of the through electrode 114 is located in the opening 4 a of the insulating layer 4 and is physically and electrically connected to the external electrode 6. The through electrode 115 extends in the Z direction, is physically and electrically connected to the three internal electrodes 113, and the other end is exposed from the surface 111a. The tip of the through electrode 115 is located in the opening 4 b of the insulating layer 4 and is physically and electrically connected to the external electrode 7. That is, the internal electrode 112 is electrically connected to the external electrode 6 by the through electrode 114, and the internal electrode 113 is electrically connected to the external electrode 7 by the through electrode 115.

  The second varistor section 120 includes a substantially rectangular parallelepiped varistor element body (first varistor element body) 121 and three pairs of internal electrodes (third and fourth internal electrodes) facing each other in the varistor element body 121. 122 and 123 and through conductors 124 and 125 are provided. The varistor element body 121 includes a surface (third surface) 121a and a surface (fourth surface) 121b facing each other in the Z direction. The insulating layer 5 is formed on the surface 121a, and the surface 121b is joined to the surface 8b of the heat radiating portion 8. The internal electrodes 122 and 123 are offset in the X direction and partly face each other in the Z direction. The internal electrodes 122 and the internal electrodes 123 are alternately stacked via varistor layers.

  The through electrode 124 extends in the Z direction, is physically and electrically connected to the three internal electrodes 122, has a tip exposed from the surface 121 a, and is covered with the insulating layer 5. The through electrode 125 extends in the Z direction, is physically and electrically connected to the three internal electrodes 123, has a tip exposed from the surface 121 a, and is covered with the insulating layer 5. The first varistor part 110 and the second varistor part 120 are formed symmetrically with respect to the heat dissipation part 8.

  A method for manufacturing the varistor V5 will be described. The varistor V5 is manufactured by the same manufacturing method as the varistor V2 according to the second embodiment, but the configuration of the internal electrodes in the first and second varistor portions is different, so that the green laminate formed in the lamination step S5. The structure of the aggregate substrate formed in the firing step S6 is partially different. This point will be described with reference to FIG.

  FIG. 20A is a schematic cross-sectional view of the green laminate. The green laminated body 300D of the fifth embodiment includes a plurality of green element bodies 30D. The green laminate 300D includes a heat dissipation green portion 308, a first varistor green portion 410, and a second varistor green portion 420.

  The first varistor green part 410 includes a varistor green layer (first varistor green layer) 411, a plurality of internal electrode patterns 412 and 413, and a plurality of through conductor patterns 414 and 415. The plurality of internal electrode patterns 412 and 413 correspond to the internal electrodes 112 and 113, respectively. The plurality of through conductor patterns 414 and 415 correspond to the through conductors 114 and 115.

  The first varistor green part 410 can be formed by laminating each of the plurality of internal electrode patterns 412 and 413 and the varistor green sheets formed with the plurality of through conductor patterns 414 and 415 in a predetermined order. . The varistor green layer 411 includes a main surface (first main surface) 411a and a main surface (second main surface) 411b that face each other in the Z direction. The main surface 411b is joined to the main surface 308a of the heat dissipation green portion 308.

  The second varistor green part 420 includes a varistor green layer (first varistor green layer) 421, a plurality of internal electrode patterns 422, 423, and a plurality of through conductor patterns 424, 425. The plurality of internal electrode patterns 422 and 423 correspond to the internal electrodes 122 and 123, respectively. The plurality of through conductor patterns 424 and 425 correspond to the through conductors 124 and 125.

  The second varistor green part 420 can be formed by laminating each of the plurality of internal electrode patterns 422 and 423 and the varistor green sheets on which the plurality of through conductor patterns 424 and 425 are formed in a predetermined order. . The varistor green layer 421 includes a main surface (third main surface) 421a and a main surface (fourth main surface) 421b facing each other in the Z direction. The main surface 421b is joined to the main surface 308a of the heat dissipation green portion 308. The first varistor green part 410 and the second varistor green part 420 are formed symmetrically with respect to the heat dissipation green part 308.

  Subsequently, a collective substrate 31D according to the fifth embodiment will be described with reference to FIG. The collective substrate 31D includes a plurality of element bodies 3D. The collective substrate 31D includes a heat dissipation layer 9, a first varistor part 110 formed by firing the first varistor green part 410, and a second varistor green part 420 formed by firing. And a varistor portion 120. The collective substrate 31 </ b> D has a symmetric configuration with respect to the heat dissipation layer 9.

  The insulating layers 45 and 46 are formed on the collective substrate 31D thus formed, and a plurality of pairs of external electrodes 6 and 7 are formed, thereby completing the collective substrate with external electrodes. By cutting this collective substrate with external electrodes, a plurality of varistors V5 are completed.

  Also in this varistor V5, the varistor element bodies 111 and 121 are mainly composed of ZnO, and the heat radiating portion 8 is composed of Ag, which is a metal, and a metal oxide containing ZnO, which is a principal element of the varistor element bodies 111, 121. It is made of a composite material. Therefore, as in the first embodiment, the bonding strength between the first varistor part 110 and the heat radiating part 8 is sufficiently secured, and is transmitted from the external element to the first varistor part 110 via the external electrodes 6 and 7. The heat is efficiently radiated through a conduction path formed over the side surface exposed from the side surface 80a in the heat radiating portion 8. In addition, the bonding strength between the second varistor part 120 and the heat dissipation part 8 is sufficiently ensured.

  Further, the shrinkage rate during firing of the heat dissipating green part 308 is different from the shrinkage rate during firing of the first and second varistor green parts 410 and 420, but the first varistor green part is formed on the main surface 308a of the heat dissipating green part 308. 410 is in contact, the second varistor green part 420 is in contact with the main surface 308b of the heat dissipation green part 308, and the heat dissipation green part 308 is sandwiched between the first varistor green part 410 and the second varistor green part 420. Therefore, it is possible to prevent the occurrence of warpage during firing and form the planar aggregate substrate 31D. Since the external electrodes 6 and 7 are formed on the flat aggregate substrate and cut to obtain individual varistors V5, a plurality of varistors V5 having high heat dissipation efficiency can be easily manufactured.

  The present invention is not limited to the above embodiment, and various modifications can be made.

  In the first to fifth embodiments, the first varistor green parts 310, 360, 390, 410 and the second varistor green parts 320, 370, 400, 420 in the green laminated bodies 300, 300A to 300D dissipate heat. The first varistor portions 19, 69, 298, 419 and the second varistor portions 29, 79, 299, 429 are dissipated in the collective substrates 31, 31A to 31D. The layers 9 and 89 are formed symmetrically, and in the varistors V1 to V5, the first varistor portions 10, 60, 90, and 110 and the second varistor portions 20, 79, 100, and 120 are radiating portions 8, 80. However, the present invention is not limited to this. The first varistor green portions 310, 360, 390, 410 and the second varistor green portions 320, 370, 400, 420 in the green laminates 300, 300A to 300D may be shifted in the X direction, or configured. The thicknesses of the elements may be different. Accordingly, the first varistor portions 19, 69, 298, 419 and the second varistor portions 29, 79, 299, 429 in the collective substrates 31, 31A to 31D may be shifted in the X direction, and the configuration The thicknesses of the elements may be different. Further, the first varistor portions 10, 60, 90, 110 and the second varistor portions 20, 79, 100, 120 in the varistors V1 to V5 may be displaced in the X direction, and the thickness of the constituent elements may be increased. Each may be different.

  In the first and fourth embodiments, the surface electrodes 13, 14, 23, 24, 98a, 98b, 108a, and 108b are formed by firing in the firing step S6, but the present invention is not limited to this. After the firing step S6, the surface electrodes 13, 14, 23, 24, 98a, 98b, 108a, and 108b may be printed on the aggregate substrate formed in the firing step S6.

  In each of the above-described embodiments, ZnO is exemplified as the semiconductor ceramic that is the main component of the varistor element bodies 11, 21, 61, 71, 91, 101, 111, 121. In addition, SrTiO3, BaTiO3, SiC, or the like may be used.

  The varistors V1 to V5 may be connected to non-GaN-based nitride semiconductor LEDs such as InGaNAs-based semiconductor LEDs, or may be connected to non-nitride-based semiconductor LEDs or LDs. Various electronic elements that generate heat during operation, such as a field effect transistor (FET) and a bipolar transistor, may be connected without being limited to the LED.

  V1 to V5 ... Varistor, 3 ... Element, 4, 5 ... Insulating layer, 6, 7 ... External electrode, 8 ... Heat radiation part, 10 ... First varistor part, 11, 21 ... Varistor element body, 12 ... Internal electrode , 13, 14 ... surface electrode, 19 ... first varistor part, 20 ... second varistor part, 29 ... second varistor part, 30 ... green body, 31 ... collective substrate, 32 ... collective substrate with external electrodes , 300 ... Green laminated body, 308 ... Heat dissipating green part, 309 ... Heat dissipating green sheet, 310 ... First varistor green part, 311 ... Varistor green layer, 312 ... Internal electrode pattern, 313 ... Surface electrode pattern, 320 ... Second The barista green club.

Claims (14)

A first varistor element layer containing ZnO as a main component and exhibiting voltage non-linear characteristics; and a plurality of varistor elements arranged in the extending direction of the first varistor element layer in the first varistor element layer. A first varistor section having a first main surface and a second main surface facing each other,
A second varistor element layer containing ZnO as a main component and exhibiting a voltage non-linear characteristic; and a plurality of varistor element layers arranged in the extending direction of the second varistor element layer in the second varistor element layer. A second varistor section having a third main surface and a fourth main surface facing each other,
A heat dissipating layer having a fifth main surface and a sixth main surface facing each other, made of a composite material of a metal and a metal oxide, and having a shrinkage ratio different from that of the first and second varistor element layers;
With
The fifth main surface of the heat dissipation layer is in contact with the second main surface of the first varistor portion, and the sixth main surface of the heat dissipation layer is the fourth main surface of the second varistor portion. In contact with the main surface,
In the heat dissipation layer, a heat dissipation path is established by a metal contained in the heat dissipation layer. The first varistor section includes a plurality of pairs of first surface electrodes formed on the first main surface at least partially facing each of the plurality of first internal electrodes.
The second varistor section includes a plurality of pairs of second surface electrodes formed on the third main surface at least partially facing each of the plurality of second internal electrodes. The aggregate substrate according to claim 1. The first varistor portion has a plurality of third internal electrodes facing each of the plurality of first internal electrodes in a facing direction of the first main surface and the second main surface,
The second varistor section includes a plurality of fourth internal electrodes facing each of the plurality of second internal electrodes in a facing direction of the third main surface and the fourth main surface. The collective substrate according to claim 1. A plurality of first external electrodes electrically connected to each of one first surface electrode in each pair of the plurality of pairs of first surface electrodes;
3. A plurality of second external electrodes electrically connected to each of the other first surface electrodes in each pair of the plurality of pairs of first surface electrodes. The collective board described. A plurality of first external electrodes electrically connected to each of the plurality of first internal electrodes;
The collective substrate according to claim 3, further comprising a plurality of second external electrodes electrically connected to each of the plurality of second internal electrodes. The heat dissipation layer contains Ag as a metal,
The Ag contained in the heat radiating layer is diffused in the first varistor element layer and the second varistor element layer. Collective board.   The collective substrate according to claim 1, wherein the heat dissipation layer contains ZnO as a metal oxide.   The heat dissipation path in the heat dissipation layer is established between the fifth main surface and a position to be exposed by cutting, according to any one of claims 1 to 7. Collective board. Varistor green sheet containing a varistor composition powder mainly composed of ZnO for forming a varistor layer exhibiting voltage nonlinear characteristics, a varistor green sheet having an internal electrode pattern formed thereon, and a composite of metal and metal oxide A preparatory step of preparing a predetermined number of heat dissipating green sheets made of a material and having a shrinkage rate different from that of the varistor layer;
The varistor green sheet prepared in the preparation step, the varistor green sheet on which the internal electrode pattern is formed, and the heat dissipating green sheet are laminated to form a first varistor green part, a second varistor green part, and a heat dissipating green. A laminating step of forming a green laminate having a portion;
A firing step of firing the green laminate to obtain an aggregate substrate;
With
In the lamination step,
The first varistor green portion includes a first varistor green layer on which the varistor green sheets are stacked, and a plurality of the varistor green portions arranged in the extending direction of the first varistor green layer in the first varistor green layer. The internal electrode pattern, and having a first main surface and a second main surface facing each other,
The second varistor green portion includes a second varistor green layer on which the varistor green sheets are stacked, and a plurality of varistor green portions arranged in the extending direction of the second varistor green layer in the second varistor green layer. And having the third main surface and the fourth main surface facing each other,
The heat-dissipating green part is formed by stacking the heat-dissipating green sheets, and has a fifth main surface and a sixth main surface facing each other;
The fifth main surface of the heat dissipation green portion is in contact with the second main surface of the first varistor green portion, and the sixth main surface of the heat dissipation green portion is the second varistor green. So as to come into contact with the fourth main surface of the part,
A method for manufacturing an aggregate substrate, comprising: stacking the varistor green sheet, the varistor green sheet on which the internal electrode pattern is formed, and the heat dissipation green sheet to form the green laminate. In the preparation step, a predetermined number of surface electrode patterns are prepared,
The green laminate formed in the lamination step is
The first varistor green part is a pair of surfaces formed on the first main surface at least partially facing each of the plurality of internal electrode patterns arranged in the first varistor green part. It further has an electrode pattern,
The second varistor green part is a pair of surfaces formed on the third main surface so that at least a part of each of the plurality of internal electrode patterns arranged in the second varistor green part is opposed to each other. The method for manufacturing a collective substrate according to claim 9, further comprising an electrode pattern. The green laminate formed in the lamination step is
The first varistor green part is at least partially opposed to each of the plurality of internal electrode patterns arranged in the first varistor green part in the opposing direction of the first and second main surfaces. A plurality of the internal electrode patterns disposed in one varistor green layer;
The second varistor green part is arranged such that at least a part of each of the plurality of internal electrode patterns arranged in the second varistor green part is opposed to the third and fourth main surfaces in the opposing direction. The method for manufacturing an aggregate substrate according to claim 9, further comprising a plurality of the internal electrode patterns arranged in the two varistor green layers. The heat dissipation green sheet contains Ag as a metal,
In the said baking process, Ag contained in the said heat dissipation green sheet diffuses in a said 1st varistor green layer and a said 2nd varistor green layer, It is any one of Claims 9-11 characterized by the above-mentioned. The manufacturing method of the collective substrate as described.   The method of manufacturing an aggregate substrate according to any one of claims 9 to 12, wherein the heat dissipation green sheet contains ZnO as a metal oxide. Further comprising a cutting step of cutting the aggregate substrate to obtain a plurality of element bodies;
In the cutting step, the aggregate substrate is cut so that a heat dissipation path that is established by the metal included in the heat dissipation layer and extends from a surface corresponding to the fifth main surface of the heat dissipation green portion is exposed. The method for manufacturing a collective substrate according to any one of claims 9 to 13.

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