JP5776512B2 - ESD protection parts - Google Patents

ESD protection parts Download PDF

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JP5776512B2
JP5776512B2 JP2011257766A JP2011257766A JP5776512B2 JP 5776512 B2 JP5776512 B2 JP 5776512B2 JP 2011257766 A JP2011257766 A JP 2011257766A JP 2011257766 A JP2011257766 A JP 2011257766A JP 5776512 B2 JP5776512 B2 JP 5776512B2
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discharge
discharge electrode
inducing
electrode
edge
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JP2013114803A (en
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秀信 梅田
秀信 梅田
高弘 佐藤
高弘 佐藤
佐藤 真一
真一 佐藤
真 吉野
真 吉野
琢生 服部
琢生 服部
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Tdk株式会社
Tdk株式会社
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  The present invention relates to an electrostatic protection component that protects an electronic device from ESD (Electro-Static Discharge).
  As an electrostatic protection component, an element body in which a plurality of ceramic layers are stacked, and a pair of discharge electrodes arranged in the same layer apart from each other in the element body, the element body includes a pair of discharge electrodes, What has the discharge induction part which connects a pair of discharge electrode while contacting is known (for example, refer patent document 1).
International Publication No. 2009/098944 Pamphlet
  In the electrostatic protection component described in Patent Document 1, the discharge inducing portion is in contact with the pair of discharge electrodes and is adjacent to the opposed portion of the pair of discharge electrodes and the cavity positioned between the opposed portions, and the pair of discharge electrodes And it arrange | positions in the layer different from the said cavity part. In general, the discharge inducing portion is destroyed at the location where the discharge is caused by the discharge. Therefore, in the electrostatic protection component described in Patent Document 1, breakdown due to discharge in the discharge inducing portion proceeds mainly in the stacking direction of the ceramic layers, that is, in the thickness direction of the discharge inducing portion.
  If the discharge inducing portion is destroyed in the thickness direction, it is difficult for discharge to occur along the discharge inducing portion. For this reason, the electrostatic protection component described in Patent Document 1 has a limited number of discharges, and the discharge start voltage changes (the discharge start voltage increases), so that the durability of the electrostatic protection component is low. Has a point. It is possible to increase the durability of the electrostatic protection component by increasing the thickness of the discharge inducing portion. However, in this case, as the thickness of the discharge inducing portion is increased, the height of the electrostatic protection component is increased, which causes new problems such as preventing the static protection component from being lowered and increasing the cost. I will.
  The present invention has been made to solve such a problem, and an object thereof is to provide an electrostatic protection component capable of enhancing durability.
An electrostatic protection component according to the present invention includes an element body in which a plurality of ceramic layers are laminated, and a first discharge electrode and a second discharge electrode disposed in the same layer apart from each other in the element body,
The element body has a discharge inducing portion that contacts the first discharge electrode and the second discharge electrode and connects the first discharge electrode and the second discharge electrode, and the first discharge electrode and the second discharge electrode are separated from each other. A first region opposed to the cavity in the direction to be separated and a second region opposed to the solid part in a direction away from each other, and the discharge inducing portion is divided into the cavity and the solid portion. The first discharge electrode and the second discharge electrode are connected so as to be in contact with each other.
  In the electrostatic protection component according to the present invention, the first discharge electrode and the second discharge electrode are opposed to each other through the cavity in the direction away from each other and through the solid portion in the direction away from each other. The discharge inducing portion connects the first discharge electrode and the second discharge electrode so as to be in contact with the cavity portion and the solid portion. In this case, since the solid portion is located between the first discharge electrode and the second discharge electrode, the breakdown due to the discharge is caused by the stacking direction of the ceramic layers (hereinafter sometimes simply referred to as “stacking direction”). It is suppressed that the solid part proceeds in the direction orthogonal to the direction of travel and the discharge inducing part proceeds in the stacking direction. Therefore, durability as an electrostatic protection component can be enhanced.
  The discharge inducing part preferably has a first part constituting a solid part. In this case, the breakdown due to the discharge reliably proceeds in the solid portion (first portion) in the direction orthogonal to the stacking direction and further suppresses the progress of the discharge inducing portion in the stacking direction. For this reason, durability as an electrostatic protection component can further be improved.
  The cavity portion includes a region located on the first discharge electrode and the second discharge electrode so as to overlap the first discharge electrode and the second discharge electrode, and the discharge inducing portion is in contact with the region of the cavity portion. It is preferable that the first discharge electrode and the second discharge electrode are connected to each other.
  Discharge mainly occurs along the surface of the discharge inducing portion in contact with the cavity. For this reason, if the cavity exists only between the first discharge electrode and the second discharge electrode, the discharge occurs not only on the surface of the first part but also on the surface of the discharge inducing part contacting the cavity in the stacking direction. When the discharge inducing portion has the first portion, the separation distance (gap width) between the first discharge electrode and the second discharge electrode is designed using the surface of the first portion as a discharge path. Therefore, when a discharge occurs not on the surface of the first portion but on the surface of the discharge inducing portion that is in contact with the cavity in the stacking direction, it is difficult to obtain an electrostatic protection component having the designed characteristics.
  Therefore, the first discharge electrode and the second discharge electrode are included so that the cavity overlaps the first discharge electrode and the second discharge electrode, and the discharge inducing portion is in contact with the first discharge electrode. When the electrode and the second discharge electrode are connected, the volume of the cavity is increased by the region in the stacking direction of the ceramic layers. The discharge distance through the surface of the first portion is extremely shorter than the discharge distance through the surface of the discharge inducing portion that is in contact with the region of the cavity portion in the stacking direction, and discharge is reliably generated in the first portion. For this reason, the electrostatic protection component which has the characteristic as a design can be obtained. Moreover, the destruction of the discharge inducing portion in the stacking direction can be further suppressed, and the durability as an electrostatic protection component can be further enhanced.
  It is preferable that the discharge inducing portion further includes a second portion that is continuous with the first portion and does not overlap the first discharge electrode and the second discharge electrode when viewed from the stacking direction of the ceramic layers. In this case, the region destroyed by the discharge in the discharge inducing portion further expands in the direction orthogonal to the stacking direction. As a result, the durability as an electrostatic protection component can be further enhanced.
  The first discharge electrode extends in the first direction, has a first tip in the first direction and a first side edge extending along the first direction, and the second discharge electrode extends in the first direction. And having a second tip in the first direction and a second side edge extending along the first direction. The first discharge electrode and the second discharge electrode are respectively the first side edge and the second side edge. Is preferably arranged so that the first side edge and the second side edge are opposed to each other so that the first area and the second area are included.
  In this case, the first discharge electrode has a first side edge extending along the first direction, the second discharge electrode has a second side edge extending along the first direction, and the first discharge The electrode and the second discharge electrode are arranged so that the first side edge and the second side edge face each other so that the first side edge and the second side edge are included in the first region and the second region, respectively. Has been placed. For this reason, between the 1st discharge electrode and the 2nd discharge electrode, it has the composition discharged between the 1st side edge and the 2nd side edge. In other words, the discharge is not concentrated on each tip, and the discharge can be performed at the side edges that are extended. Thereby, the discharge part between a 1st discharge electrode and a 2nd discharge electrode can be lengthened, and durability as an electrostatic protection component can further be improved.
  ADVANTAGE OF THE INVENTION According to this invention, the electrostatic protection component which can improve durability can be provided.
It is a perspective view of the electrostatic protection component which concerns on embodiment of this invention. It is an expansion perspective view of an element object of an electrostatic protection component concerning an embodiment of the present invention. It is the figure which looked at the discharge part of the electrostatic protection component from the lamination direction. It is a figure for demonstrating the cross-sectional structure along the IV-IV line | wire shown in FIG. It is a figure for demonstrating the cross-sectional structure along the VV line shown in FIG. It is a schematic diagram for demonstrating the material structure of a discharge induction part. It is a flowchart which shows an example of the manufacturing method of an electrostatic protection component. It is the figure which looked at the discharge part of the electrostatic protection component which concerns on a modification from the lamination direction.
  FIG. 1 is a perspective view of an electrostatic protection component according to this embodiment. FIG. 2 is an exploded perspective view of the element body of the electrostatic protection component according to the present embodiment. FIG. 3 is a view of the discharge portion of the electrostatic protection component as viewed from the stacking direction. In FIG. 3, the ceramic layer 2 on one sheet of the first discharge electrode 4A and the second discharge electrode 4B is omitted. FIG. 4 is a diagram for explaining a cross-sectional configuration along the line IV-IV shown in FIG. FIG. 5 is a diagram for explaining a cross-sectional configuration along the line VV shown in FIG. In the following description, the direction in which the element body 3 extends is the longitudinal direction D1, the direction perpendicular to the longitudinal direction D1 in the planar direction of the ceramic layer 2 is the short direction D2, and the direction in which the ceramic layer 2 is laminated is the lamination direction D3. And
  The electrostatic protection component 1 according to the present embodiment is an electronic component that is mounted on a circuit board of an electronic device and protects the electronic device from ESD. As shown in FIGS. 1 to 5, the electrostatic protection component 1 includes an element body 3 in which a plurality of ceramic layers 2 are stacked, and a first discharge electrode 4 </ b> A disposed in the same layer while being separated from each other in the element body 3. And the second discharge electrode 4B, and the external electrode 6A and the external electrode 6B formed on the opposite end surfaces 3a and 3b of the element body 3, respectively. The first discharge electrode 4A is electrically connected to the external electrode 6A, and the second discharge electrode 4B is electrically connected to the external electrode 6B. The element body 3 has a discharge inducing portion 8 that contacts the first discharge electrode 4A and the second discharge electrode 4B and connects the first discharge electrode 4A and the second discharge electrode 4B. The element body 3 has a hollow portion 7 that is in contact with the first discharge electrode 4A and the second discharge electrode 4B.
  The discharge inducing portion 8 includes a discharge inducing portion 8A, a discharge inducing portion 8B, and a discharge inducing portion 8C, and has a function of easily generating a discharge between the first discharge electrode 4A and the second discharge electrode 4B. Yes.
  The discharge inducing portion 8A is a portion located in the gap portion GP between the first discharge electrode 4A and the second discharge electrode 4B in the discharge inducing portion 8 when viewed from the stacking direction D3. That is, the discharge inducing portion 8A is sandwiched between the first discharge electrode 4A and the second discharge electrode 4B in the short direction D2, and connects the first discharge electrode 4A and the second discharge electrode 4B. A part of the side edge 14A of the first discharge electrode 4A facing the gap part GP and a part of the side edge 14B of the second discharge electrode 4B facing the gap part GP are in contact with the discharge inducing part 8A. The discharge inducing portion 8A is adjacent to and in contact with a cavity portion 7a described later in the longitudinal direction D1 at the gap portion GP. The discharge inducing portion 8A only needs to be formed in the gap portion GP so as to connect the first discharge electrode 4A and the second discharge electrode 4B, and the size, shape, and range of the discharge inducing portion 8A are not particularly limited. In the present embodiment, the discharge inducing portion 8 includes a pair of discharge inducing portions 8A, and the pair of discharge inducing portions 8A is disposed with the cavity portion 7a sandwiched in the longitudinal direction D1.
  The discharge inducing portion 8B is a portion of the discharge inducing portion 8 that is continuous with the discharge inducing portion 8A in the longitudinal direction D1 and does not overlap the first discharge electrode 4A and the second discharge electrode 4B when viewed from the stacking direction D3. (See FIG. 3).
The discharge inducing part 8C is the remaining part of the discharge inducing part 8 excluding the discharge inducing parts 8A and 8B.
The discharge inducing portion 8C includes a portion adjacent to the front end 12A of the first discharge electrode 4A or the front end 12B of the second discharge electrode 4B in the longitudinal direction D1, adjacent to the first discharge electrode 4A in the stacking direction D3, and the first discharge electrode 4A. And a portion adjacent to the second discharge electrode 4B in the stacking direction D3 and in contact with the upper surface 16B of the second discharge electrode 4B (see FIG. 4).
  As shown in FIG. 4, the cavity portion 7 includes a cavity portion 7a and a cavity portion 7b, and the thermal expansion of the first discharge electrode 4A, the second discharge electrode 4B, the ceramic layer 2 and the discharge inducing portion 8 during discharge is performed. Has the function of absorbing. The cavity 7a is formed in a gap GP between the first discharge electrode 4A and the second discharge electrode 4B. That is, a part of the gap portion GP of the side edge 14 </ b> A of the first discharge electrode 4 </ b> A is exposed to the cavity portion 7. Further, a part of the gap portion GP of the side edge 14B of the second discharge electrode 4B is exposed to the cavity portion 7. The cavity 7b is located on the first discharge electrode 4A and the second discharge electrode 4B so as to overlap the first discharge electrode 4A and the second discharge electrode 4B. That is, part of the upper surfaces 16A and 16B is exposed to the cavity 7b. Note that the size, shape, and range of the cavity 7 are not particularly limited as long as the size and position can absorb thermal expansion, and the cavity 7 has a wider range (for example, the lower surfaces 17A and 17B are also included in the cavity 7). (To be exposed).
  4A of 1st discharge electrodes and the 2nd discharge electrode 4B are the 1st area | region 70 which opposes via the cavity part 7 in the direction (short direction D2) from which the 1st discharge electrode 4A and the 2nd discharge electrode 4B mutually space | interval. And a second region 80 facing each other through the discharge inducing portion 8A in the short direction D2. The discharge inducing portion 8A functions as a solid portion sandwiched between the second region 80 of the first discharge electrode 4A and the second region 80 of the second discharge electrode 4B in the short direction D2.
  4 A of 1st discharge electrodes have the main-body part 11A extended along the longitudinal direction D1 (1st direction) toward the end surface 3b side of the other side from the end surface 3a of the element | base_body 3 (refer especially FIG. 3). The main body 11A has a distal end 12A and a base end 13A in the longitudinal direction D1, and side edges 14A and side edges 15A extending along the longitudinal direction D1. The main body 11A has a long rectangular shape, with the distal end 12A and the base end 13A constituting a short side, and the side edges 14A and 15A constituting a long side. That is, the side edges 14A and 15A are longer than the distal end 12A and the proximal end 13A. 11 A of main-body parts are arrange | positioned slightly on the side surface 3c side of the element | base_body 3 rather than the center position in the transversal direction D2. The base end 13A is exposed from the end face 3a of the element body 3 and connected to the external electrode 6A. The front end 12A extends to a position separated from the end surface 3b, and is disposed at a position closer to the end surface 3b than the center position in the longitudinal direction D1. The side edge 14A is an edge portion on the side surface 3d side of the element body 3, and is disposed slightly on the side surface 3c side with respect to the center position in the lateral direction D2. The side edge 15A is an edge portion on the side surface 3c side of the element body 3, and is disposed at a position separated from the side surface 3c. The length of the main body 11A may be longer or shorter than that shown in FIG.
  The second discharge electrode 4B has a point-symmetric relationship with the first discharge electrode 4A around the center of the element body 3 when viewed from the stacking direction D3. That is, the second discharge electrode 4B has a main body portion 11B extending along the longitudinal direction D1 from the end surface 3b of the element body 3 toward the opposite end surface 3a (see particularly FIG. 3). The main body 11B has a distal end 12B and a base end 13B in the longitudinal direction D1, and a side edge 14B and a side edge 15B extending along the longitudinal direction D1. The main body 11B has a long rectangular shape, with the tips 12B and 13B constituting short sides and the side edges 14B and 15B constituting long sides. That is, the side edges 14B and 15B are longer than the distal end 12B and the proximal end 13B. The main body portion 11B is disposed slightly on the side surface 3d side of the element body 3 with respect to the center position in the short direction D2. The base end 13B is exposed from the end surface 3b of the element body 3 and connected to the external electrode 6B. The distal end 12B extends to a position separated from the end surface 3a, and is disposed at a position closer to the end surface 3a than the center position in the longitudinal direction D1. The side edge 14B is an edge portion on the side surface 3c side of the element body 3, and is disposed slightly on the side surface 3d side with respect to the center position in the lateral direction D2. The side edge 15B is an edge portion on the side surface 3d side of the element body 3, and is disposed at a position separated from the side surface 3d. Note that the length of the main body 11B may be longer or shorter than that shown in FIG.
  As shown in FIG. 3, the first discharge electrode 4A and the second discharge electrode 4B are such that the side edges 14A and 15A and the side edges 14B and 15B are included in the first region 70 and the second region 80, respectively. The side edges 14A and the side edges 14B are arranged to face each other. Further, the region on the tip 12A side of the side edge 14A of the first discharge electrode 4A and the region on the tip 12B side of the side edge 14B of the second discharge electrode 4B face each other at a distance from each other. A gap GP is formed between 4A and the second discharge electrode 4B. The gap width (the distance between the side edge 14A and the side edge 14B) of the gap part GP is 10 to 100 μm. The gap part GP is formed only in a region where the side edge 14A and the side edge 14B face each other (see FIG. 3). Further, in the present embodiment, the first discharge electrode 4A is configured only by the main body portion 11A having a long rectangular shape, and does not have a portion facing the tip 12B of the second discharge electrode 4B in the longitudinal direction D1. . The second discharge electrode 4B is constituted only by a main body portion 11B having a long rectangular shape, and does not have a portion facing the tip 12A of the first discharge electrode 4A in the longitudinal direction D1. With such a configuration, when a voltage higher than a predetermined voltage is applied to the external electrode 6A and the external electrode 6B, the side edge 14A and the side of the gap GP are between the first discharge electrode 4A and the second discharge electrode 4B. Discharge occurs only between the edge 14B.
  Next, the material of each component will be described in detail.
  The first discharge electrode 4A and the second discharge electrode 4B are made of a conductive material containing Ag, Pd, Au, Pt, Cu, Ni, Al, Mo, and W. For example, the first discharge electrode 4A and the second discharge electrode 4B can use an Ag / Pd alloy, an Ag / Cu alloy, an Ag / Au alloy, an Ag / Pt alloy, or the like as an alloy. The external electrodes 6A and 6B are made of a conductive material containing Ag, Pd, Au, Pt, Cu, Ni, Al, Mo, and W. For example, for the external electrodes 6A and 6B, an Ag / Pd alloy, an Ag / Cu alloy, an Ag / Au alloy, an Ag / Pt alloy, or the like can be used as an alloy.
The ceramic layer 2 is made of Fe 2 O 3 , NiO, CuO, ZnO, MgO, SiO 2 , TiO 2 , MnCO 3 , SrCO 3 , CaCO 3 , BaCO 3 , Al 2 O 3 , ZrO 2 , B 2 O 3, etc. It is comprised by the material which mixed the single material in them, or two or more types. Moreover, glass may be contained. The ceramic layer 2 preferably contains copper oxide (CuO, Cu 2 O) in order to enable low-temperature sintering.
The discharge inducing part 8 includes Fe 2 O 3 , NiO, CuO, ZnO, MgO, SiO 2 , TiO 2 , MnCO 3 , SrCO 3 , CaCO 3 , BaCO 3 , Al 2 O 3 , ZrO 2 , B 2 O 3, etc. It is comprised by the material which mixed the independent material in 2 or 2 types or more. The discharge inducing portions 8A, 8B, and 8C include Ag, Pd, Au, Pt, Ag / Pd alloy, Ag / Cu alloy, Ag / Au alloy, Ag / Pt alloy, or other metal particles, or RuO 2 or other semiconductor particles. Is preferably contained. Moreover, glass may be contained. The discharge inducing part 8 preferably contains tin oxide (SnO, SnO 2 ).
  FIG. 6 is a schematic diagram for explaining the material configuration of the discharge inducing portion. With reference to FIG. 6, the structure in the case of using a preferable material will be described. FIG. 6 is a schematic configuration diagram for explanation, and the size and number of each particle are shown in a deformed state.
In the discharge inducing portion 8, tin oxide (SnO 2 ) particles 22 and an Ag / Pd alloy are contained in a ceramic insulator 21 containing, as a main component, an oxide of Mg, Cu, Zn, Si, Sr, or the like. The metal particles 23 are present in a mixed state. The mixed state is a state in which the Ag / Pd alloy metal particles 23 are not hardened at one place but the tin oxide particles 22 enter between the metal particles 23. The tin oxide particles 22 are present in an unsintered particle state (however, some particles are in the form of agglomerated powder). Tin oxide functions as a semiconductor material and can be discharged even when the gap size of the gap portion GP is larger than when the metal particles 23 exist alone by being disposed between the metal particles 23. The alloy ratio of the Ag / Pd alloy of the metal particles 23 is 95/5 to 30/70. The content of the tin oxide particles 22 is preferably 5/95 to 80/20 wt% in a tin oxide / ceramic insulator ratio. The content of the metal particles 23 is preferably 10 to 35 vol% with respect to the discharge inducing portion 8.
  The ceramic layer 2 contains Mg, Cu, Zn, Si, Sr oxide, and the like as main components, and contains copper oxide (CuO) particles 24 in a ceramic containing glass. The content of the copper oxide particles 24 is preferably 0.01 to 5 wt%.
  The first discharge electrode 4A and the second discharge electrode 4B are made of a conductor material whose main component is an Ag / Pd alloy. The alloy ratio of the Ag / Pd alloy of the first discharge electrode 4A and the second discharge electrode 4B is 95/5 to 30/70. The alloy ratio of the Ag / Pd alloy of the first discharge electrode 4A and the second discharge electrode 4B and the Ag / Pd alloy of the metal particles 23 is preferably the same.
  Tin oxide is characterized by a very high sintering temperature (specifically, about 1300 ° C.) and low reactivity with other elements. Accordingly, the tin oxide remains in the form of particles at the temperature during firing of the element body 3 and does not react with the metal particles 23 even if the metal particles 23 exist around. In the discharge inducing portion 8, the following effects are achieved by making the tin oxide particles 22 and the metal particles 23 coexist. That is, at the time of firing the element body 3, the tin oxide particles 22 remain in the form of particles without reacting with the surrounding metal particles 23. As described above, the tin oxide particles 22 remain without reacting, so that the movement of the metal particles 23 in the discharge inducing portion 8 is limited. Since the metal particles 23 whose movement is restricted do not react with each other, it is possible to prevent a short circuit between the discharge electrodes 4A and 4B (or a decrease in insulation resistance) due to the connection between the metal particles 23. .
  Further, since the discharge inducing portion 8 contains an insulator such as the ceramic insulator 21, insulation between the first discharge electrode 4A and the second discharge electrode 4B can be ensured.
  Moreover, in the electrostatic protection component 1, while the ceramic layer 2 contains the highly reactive copper oxide particles 24, the discharge inducing portion 8 contains the tin oxide particles 22 having a high sintering temperature and low reactivity. By adopting the configuration, the following effects are achieved. That is, even if the ceramic layer 2 contains the copper oxide particles 24, the diffusion of the copper oxide particles 24 into the discharge inducing portion 8 is suppressed by the tin oxide particles 22. Thus, since the diffusion of the copper oxide particles 24 is suppressed, the constituent material in the portion other than the tin oxide can be freely selected in the discharge inducing portion 8 (that is, the discharge inducing portion 8 is a tin oxide). And other materials, but other materials can be freely selected). As described above, the element body 3 can contain copper oxide while ensuring the freedom of selection of the constituent material of the discharge inducing portion 8.
  Moreover, the discharge start voltage can be lowered by containing the metal particles 23 in the discharge inducing portion 8.
  The Ag / Pd alloy has a high melting point (specifically, about 1000 ° C.) and a low reactivity with copper oxide. While the ceramic layer 2 contains highly reactive copper oxide particles 24, the discharge inducing part 8 contains a Ag / Pd alloy having low reactivity with copper oxide as the metal particles 23. Thus, the following effects are produced. That is, even if the ceramic layer 2 contains the copper oxide particles 24, the reaction between the metal particles 23 due to the influence of the diffusion of the copper oxide particles 24 is suppressed in the discharge inducing portions 8A, 8B, and 8C. That is, it is possible to prevent the discharge electrodes 4A and 4B from being short-circuited (or the insulation resistance is lowered) by connecting the metal particles 23 to each other. Thus, the element body 3 can contain copper oxide while preventing a short circuit between the first discharge electrode 4A and the second discharge electrode 4B. Although Pd alone has a high melting point, its reactivity with copper oxide is higher than that of an Ag / Pd alloy. Therefore, the effect becomes more remarkable by using an alloyed material with Ag.
  Moreover, in the structure in which the element body 3 contains copper oxide, if a metal other than Ag / Pd is used for the first discharge electrode 4A and the second discharge electrode 4B, it reacts with the copper oxide, and the following: Problems can arise. For example, Ag / Pd may vaporize and disappear from the exposed portions of the first discharge electrode 4 </ b> A and the second discharge electrode 4 </ b> B from the element body 3 (connection portions with the external electrodes 6 </ b> A, 6 </ b> B, etc.). Moreover, if the opposing part (near side edges 14A and 14B) of the first discharge electrode 4A and the second discharge electrode 4B disappears, the gap length may vary and the characteristics may not be stable. Therefore, the first discharge electrode 4A and the second discharge electrode 4B contain an Ag / Pd alloy, so that the occurrence of such a problem can be prevented. A metal other than Ag / Pd may be used for the first discharge electrode 4A and the second discharge electrode 4B.
  Further, when an Ag / Pd alloy is contained in the discharge inducing portion 8 and an Ag / Pd alloy is contained in the discharge electrode 8, the discharge inducing portion 8 is made to have the same alloy ratio of each Ag / Pd alloy. And the Ag / Pd alloy can be prevented from reacting between the first discharge electrode 4A and the second discharge electrode 4B.
  Next, an example of a method for manufacturing the electrostatic protection component 1 will be described with reference to FIG. However, a manufacturing method is not specifically limited, The order of each process may be changed, the specific method in a process may be changed, and you may manufacture by another process.
  First, the slurry of the material which comprises the ceramic layer 2 is adjusted, and the sheet | seat for ceramic layers is created (S10). Specifically, a predetermined amount of dielectric powder containing copper oxide (CuO) and an organic vehicle containing an organic solvent and an organic binder are mixed to prepare a slurry for the ceramic layer. As the dielectric powder, a dielectric material containing, as a main component, an oxide of Mg, Cu, Zn, Si, or Sr (may be another dielectric material) can be used. Then, a slurry is apply | coated on PET film by the doctor blade method etc., and a green sheet about 20 micrometers thick is formed.
Next, a discharge portion is formed by printing at a predetermined position of the ceramic layer sheet. First, a conductive pattern of the discharge electrode before firing is formed by applying a conductive paste to the ceramic layer sheet by screen printing or the like (S20). A gap material lacquer for forming the cavity 7 is applied so as to cover a part of the first discharge electrode 4A and a part of the second discharge electrode 4B. An organic lacquer containing an organic solvent and an organic binder can be used. Thus, a portion that becomes the cavity 7 after firing is formed (S30). Next, the discharge inducing material slurry is prepared, and the slurry is applied from above the gap material lacquer to form a discharge inducing portion before firing (S40). Specifically, tin oxide, insulator, and conductor powders weighed to a predetermined amount and an organic vehicle containing an organic solvent and an organic binder are mixed to prepare a discharge inducing material slurry. For example, SnO 2 which is an industrial raw material can be used as tin oxide. Dielectric powder can be used as the insulator. As the dielectric powder, a dielectric material containing, as a main component, an oxide of Mg, Cu, Zn, Si, or Sr (may be another dielectric material) can be used. As the conductor powder, Ag / Pd powder can be used (Ag, Pd, Au, Pt, and mixtures and compounds thereof may be used). Each powder is sufficiently mixed so that tin oxide particles and Ag / Pd alloy metal particles are mixed.
  The ceramic layer sheet printed with the discharge part and the ceramic layer sheet of other layers are sequentially laminated (S50), pressed (S60), and the laminate is cut to the size of the individual electrostatic protection components. (S70). Next, each element body is fired at predetermined conditions (for example, in the atmosphere at 850 to 950 ° C. for 2 hours) (S80). At this time, the void material lacquer disappears inside the element body 3, thereby forming a cavity 7 in the discharge portion. Thereafter, a conductive paste for external electrodes is applied to the element body 3, and heat treatment is performed under predetermined conditions (for example, at 600 to 800 ° C. for 2 hours in the atmosphere), and the external electrodes are baked (S90). Thereafter, the surface of the external electrode is plated. The plating is preferably electrolytic plating. For example, Ni / Sn, Cu / Ni / Sn, Ni / Pd / Au, Ni / Pd / Ag, Ni / Ag, or the like can be used. Thus, the electrostatic protection component 1 is completed.
  As described above, in the electrostatic protection component 1, the first discharge electrode 4 </ b> A and the second discharge electrode 4 </ b> B are discharged in the short direction D <b> 2 and the first region 70 that is opposed to each other through the cavity 7. The discharge inducing part 8B and the discharge inducing part 8C are in contact with the cavity 7 and the discharge inducing part 8A so that the first discharge electrode 4A and the second inducing part 8A are in contact with each other. The discharge electrode 4B is connected. In this case, since the discharge inducing portion 8A is located between the first discharge electrode 4A and the second discharge electrode 4B, the breakdown due to the discharge proceeds in the discharge inducing portion 8A in the longitudinal direction D1, and in the stacking direction D3. Proceeding with the discharge inducing portion 8 is suppressed. Therefore, durability as the electrostatic protection component 1 can be improved.
  In the electrostatic protection component 1, the cavity 7 includes a cavity 7b located on the first discharge electrode 4A and the second discharge electrode 4B so as to overlap the first discharge electrode 4A and the second discharge electrode 4B. The discharge inducing portion 8C connects the first discharge electrode 4A and the second discharge electrode 4B so as to be in contact with the cavity portion 7b. In this case, the volume of the cavity 7 is increased by the cavity 7b in the stacking direction D3. The discharge distance through the surface of the discharge inducing portion 8A is extremely shorter than the discharge distance through the surface of the discharge inducing portion 8C that is in contact with the cavity portion 7b in the stacking direction D3, and discharge is reliably generated in the discharge inducing portion 8A. For this reason, the electrostatic protection component 1 having the characteristics as designed can be obtained. Moreover, destruction to the lamination direction D3 of the discharge induction part 8C can be suppressed further, and durability as the electrostatic protection component 1 can further be improved.
  Further, in the electrostatic protection component 1, the discharge inducing part 8 is connected to the discharge inducing part 8A and the discharge inducing part 8B does not overlap the first discharge electrode 4A and the second discharge electrode 4B when viewed from the stacking direction D3 of the ceramic layer 2. It has further. In this case, the region destroyed by the discharge in the discharge inducing portion 8 further expands in the longitudinal direction D1. As a result, the durability of the electrostatic protection component 1 can be further enhanced.
  In the electrostatic protection component 1, the first discharge electrode 4A extends in the longitudinal direction D1, has a tip 12A in the longitudinal direction D1, and side edges 14A and 15A extending in the longitudinal direction D1, and the second The discharge electrode 4B extends in the longitudinal direction D1, and has a tip 12B in the longitudinal direction D1 and side edges 14B and 15B extending along the longitudinal direction D1, and includes the first discharge electrode 4A and the second discharge electrode 4B. Are arranged with the side edges 14A, 15A and the side edges 14B, 15B facing each other so that the side edges 14A, 15A and the side edges 14B, 15B are included in the first region 70 and the second region 80, respectively. Yes. In this case, the first discharge electrode 4A has side edges 14A and 15A extending along the longitudinal direction D1, and the second discharge electrode 4B has side edges 14B and 15B extending along the longitudinal direction D1. The first discharge electrode 4A and the second discharge electrode 4B are arranged such that the side edges 14A and 15A and the side edges 14B and 15B are included in the first region 70 and the second region 80, respectively. The side edges 14B and 15B are arranged to face each other. For this reason, between 1st discharge electrode 4A and 2nd discharge electrode 4B, it has the structure which discharges between side edge 14A, 15A and side edge 14B, 15B. In other words, the discharge is not concentrated on each tip, and the discharge can be performed at the side edges that are extended. Thereby, the discharge part between 4 A of 1st discharge electrodes and the 2nd discharge electrode 4B can be lengthened, and the durability as the electrostatic protection component 1 can further be improved.
  In addition, embodiment mentioned above demonstrated embodiment of the electrostatic protection component which concerns on this invention, and the electrostatic protection component which concerns on this invention is not limited to what was described in this embodiment. The electrostatic protection component according to the present invention may be obtained by modifying the electrostatic protection component according to the embodiment or applying it to other components without changing the gist described in each claim.
  For example, the configuration of the first discharge electrode 4A and the second discharge electrode 4B is not limited to the configuration shown in FIG. 3, and the length, width, and gap size may be changed as appropriate. Further, for example, the configuration shown in FIG. 8 may be adopted.
  In the configuration shown in FIG. 8, the first discharge electrode 4A extends in the longitudinal direction D1 from the end face 3a of the element body 3, the discharge electrode 4B extends in the longitudinal direction D1 from the end face 3b of the element body 3, and the tip 12A of the discharge electrode 4A The tips 12B of the discharge electrodes 4B are opposed to each other to form a gap part GP. Further, the first discharge electrode 4A and the second discharge electrode 4B are opposed to the first region 70 that is opposed to each other via the cavity 7 in the direction away from each other (longitudinal direction D1), and through the discharge inducing portion 8A in the longitudinal direction D1. And a second region 80 facing each other. In this case, the length of the discharge portion is limited to a short range of the tips 12A and 12B.
  On the other hand, in the configuration shown in FIG. 3, the first discharge electrode 4A has a side edge 14A extending along the longitudinal direction D1, and the discharge electrode 4B has a side edge 14B extending along the longitudinal direction D1. ing. The first discharge electrode 4A and the second discharge electrode 4B are opposed to each other only at the side edges 14A and 14B, and do not have a portion that faces the tip 12A or 12B. Thus, the side edges 14A and the side edges 14B extending along the longitudinal direction D1 are opposed to each other, and between the first discharge electrode 4A and the second discharge electrode 4B, between the side edge 14A and the side edge 14B. It is configured to discharge only. The length of the gap part GP can be made longer than that of the configuration of FIG. 8 by making the side edges 14A and 14B that are longer than the tips 12A and 12B face each other. Moreover, it is set as the structure which avoids that discharge concentrates on each front-end | tip 12A and 12B, and can discharge by the side edges 14A and 14B extended long. That is, the substantial length of the discharge portion can be made longer than that shown in FIG. As a result, the gap GP between the first discharge electrode 4A and the second discharge electrode 4B can be lengthened, and the durability of the electrostatic protection component 1 can be increased.
  In addition, by not providing a portion facing the other discharge electrode on the tip 12A, 12B side, it is possible to more reliably discharge only between the side edge 14A and the side edge 14B.
  The discharge inducing portion 8 includes a pair of discharge inducing portions 8A, but is not limited thereto, and may include only one discharge inducing portion 8A. In this case, the cavity portion 7a is arranged in the gap portion GP so as to be biased in the longitudinal direction D1. Moreover, in this embodiment, although the number of the cavity parts 7a is one, it is not restricted to this, A plurality may be sufficient. In this case, the cavity portions 7a and the discharge inducing portions 8A are alternately arranged in the longitudinal direction D1.
  In the present embodiment, the discharge inducing portion 8A functions as a solid portion, but this is not restrictive. The solid part sandwiched in the short direction D2 between the second region 80 of the first discharge electrode 4A and the second region 80 of the second discharge electrode 4B may be made of the same material as the ceramic layer 2 or the like.
  Further, in the above-described embodiment, the electrostatic protection component including only the discharge portion having the electrostatic protection function is illustrated, but the present invention may be adopted for the electrostatic protection component to which other functions such as a coil portion and a capacitor portion are added. . At this time, the material of the ceramic layer 2 may be changed to an optimum material for each layer with respect to each of the discharge portion, the coil portion, and the capacitor portion.
  DESCRIPTION OF SYMBOLS 1 ... Electrostatic protection component, 2 ... Ceramic layer, 3 ... Element, 4A ... 1st discharge electrode, 4B ... 2nd discharge electrode, 6A ... External electrode, 6B ... External electrode, 7 ... Hollow part, 8, 8A, 8B , 8C ... discharge inducing portion, 12A ... tip, 12B ... tip, 14A, 15A ... side edge, 14B, 15B ... side edge.

Claims (3)

  1. An element body in which a plurality of ceramic layers are laminated;
    A first discharge electrode and a second discharge electrode disposed in the same layer apart from each other in the element body,
    The element body has a discharge inducing portion that contacts the first discharge electrode and the second discharge electrode and connects the first discharge electrode and the second discharge electrode;
    The first discharge electrode and the second discharge electrode, a first region facing through a cavity in a direction away from each other, a second region facing through a solid portion in the direction away from each other, Have
    The cavity includes a region located on the first discharge electrode and the second discharge electrode so as to overlap the first discharge electrode and the second discharge electrode,
    The discharge inducing portion connects the first discharge electrode and the second discharge electrode so as to be in contact with the region of the hollow portion and the solid portion, and a first portion constituting the solid portion And a portion that is continuous with the first portion and is positioned so as to cover the first portion and the cavity portion when viewed from the stacking direction of the ceramic layers .
  2. The discharge inducing portion further includes a second portion that is continuous with the first portion and does not overlap the first discharge electrode and the second discharge electrode when viewed from the stacking direction of the ceramic layers. The electrostatic protection component according to claim 1 .
  3. The first discharge electrode extends in a first direction, and has a first tip in the first direction and a first side edge extending along the first direction,
    The second discharge electrode extends in the first direction, and has a second tip in the first direction and a second side edge extending along the first direction,
    The first discharge electrode and the second discharge electrode are formed such that the first side edge and the second side edge are included in the first region and the second region, respectively. electrostatic discharge protection component according to claim 1 or 2, characterized in that it is disposed opposite a second side edge.
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