JP6428938B2 - ESD protection device - Google Patents

Description

  The present invention relates to an ESD protection device.

  Conventionally, as an ESD protection device, there is one described in WO2010 / 101103 (Patent Document 1). The ESD protection device is provided between the first discharge electrode and the second discharge electrode, the first discharge electrode and the second discharge electrode that are provided on the element body, and are disposed to face each other. A discharge auxiliary electrode electrically connecting the discharge electrode and the second discharge electrode; The auxiliary discharge electrode extends in the opposing direction of the first discharge electrode and the second discharge electrode.

WO2010 / 101103

  By the way, the inventor of the present application has found that the conventional ESD protection device has a problem that resistance to ESD application is low by actually using the conventional ESD protection device. And this inventor earnestly examined this phenomenon and found the following causes.

  When the discharge auxiliary electrode and the first discharge electrode are subjected to a thermal shock during ESD application, the coefficient of thermal expansion of the discharge auxiliary electrode is different from the coefficient of thermal expansion of the first discharge electrode, so that the discharge auxiliary electrode contacts the first discharge electrode. Thermal stress is generated on the surface. Due to this thermal stress, peeling (delamination) occurs between the auxiliary discharge electrode and the first discharge electrode. This peeling reduces the resistance to ESD application.

  Accordingly, an object of the present invention is to provide an ESD protection device having improved resistance to ESD application.

In order to solve the above problems, the ESD protection apparatus of the present invention is
With the body,
A first discharge electrode and a second discharge electrode provided on the element body and arranged to face each other;
A discharge auxiliary electrode provided between the first discharge electrode and the second discharge electrode and electrically connecting the first discharge electrode and the second discharge electrode;
The discharge auxiliary electrode is
A first surface direction electrode portion connected to the first discharge electrode and extending in a surface direction of the first discharge electrode;
An opposing direction electrode portion connected to the first surface direction electrode portion and extending in an opposing direction of the first discharge electrode and the second discharge electrode;
A contact surface that contacts the first discharge electrode of the first surface direction electrode portion is larger than a contact surface that contacts the first surface direction electrode portion of the counter direction electrode portion.

  According to the ESD protection apparatus of the present invention, the discharge auxiliary electrode is connected to the first discharge electrode, and is connected to the first surface direction electrode portion extending in the surface direction of the first discharge electrode and the first surface direction electrode portion. And a counter-direction electrode portion extending in a counter-direction of the first discharge electrode and the second discharge electrode. The contact surface in contact with the first discharge electrode of the first surface direction electrode portion is larger than the contact surface in contact with the first surface direction electrode portion of the counter direction electrode portion.

  When the discharge auxiliary electrode and the first discharge electrode are subjected to a thermal shock during ESD application, the coefficient of thermal expansion of the discharge auxiliary electrode is different from the coefficient of thermal expansion of the first discharge electrode, so that the discharge auxiliary electrode contacts the first discharge electrode. Thermal stress is generated on the surface. Since the area of the contact surface of the discharge auxiliary electrode is larger than that in the conventional case, the connection strength between the discharge auxiliary electrode and the first discharge electrode is improved, and the thermal stress is distributed over the entire contact surface. Therefore, peeling (delamination) between the discharge auxiliary electrode and the first discharge electrode due to local concentration of thermal stress is prevented, and resistance to ESD application is improved.

In one embodiment of the ESD protection device,
The auxiliary discharge electrode has a second surface direction electrode portion connected between the counter direction electrode portion and the second discharge electrode and extending in a surface direction of the second discharge electrode,
A contact surface of the second surface direction electrode portion that contacts the second discharge electrode is larger than a contact surface of the counter direction electrode portion that contacts the second surface direction electrode portion.

  According to the embodiment, since the area of the contact surface of the discharge auxiliary electrode with the second discharge electrode is larger than the conventional one, the connection strength between the discharge auxiliary electrode and the second discharge electrode is improved. Therefore, peeling between the auxiliary discharge electrode and the second discharge electrode is prevented, and resistance to ESD application is improved.

  In one embodiment of the ESD protection apparatus, the discharge auxiliary electrode has a plurality of counter-direction electrode portions.

  According to the embodiment, since the discharge auxiliary electrode has a plurality of counter-direction electrode portions, even if one counter-direction electrode portion stops operating, the other counter-direction electrode portion operates. It is possible to prevent deterioration of responsiveness.

  In one embodiment of the ESD protection apparatus, the content ratio of the conductive material in the first surface direction electrode portion is larger than the content ratio of the conductive material in the counter direction electrode portion.

  According to the embodiment, since the content ratio of the conductive material in the first surface direction electrode portion is larger than the content ratio of the conductive material in the counter direction electrode portion, when connecting the first discharge electrode to the primary side, The electric field concentration on the one-surface direction electrode portion is increased, and discharge becomes easier. Therefore, the discharge start voltage can be lowered and the ESD response can be improved. Furthermore, since the discharge start voltage can be lowered, resistance to ESD application is improved.

  In one embodiment of the ESD protection apparatus, the first discharge electrode is connected to the primary side, and the second discharge electrode is connected to the secondary side.

  Here, the primary side refers to the static electricity input side, and the secondary side refers to the static electricity output side.

  According to the embodiment, in the state where the first discharge electrode is connected to the primary side, the area of the contact surface of the discharge auxiliary electrode with the first discharge electrode is increased. Electrode connection is improved and ESD response is improved. In addition, since the area of the contact surface of the discharge auxiliary electrode with the first discharge electrode is increased, the electric field concentration on the first surface direction electrode portion is increased and the discharge is facilitated.

In one embodiment of the ESD protection device,
The counter-direction electrode part is
A first electrode portion on the first discharge electrode side;
A second electrode portion on the second discharge electrode side,
A third surface direction electrode portion extending in a surface direction intersecting the facing direction is connected between the first electrode portion and the second electrode portion.

  According to the embodiment, the third surface direction electrode portion is connected between the first electrode portion and the second electrode portion, since the third surface direction electrode portion extending in the surface direction intersecting the facing direction is connected. Can be made to bite into the element body, and peeling between the discharge auxiliary electrode and the element body can be prevented.

  According to the ESD protection apparatus of the present invention, it is possible to prevent peeling between the discharge auxiliary electrode and the first discharge electrode, and to improve resistance to ESD application.

It is a perspective view which shows 1st Embodiment of the ESD protection apparatus of this invention. It is XZ sectional drawing of FIG. It is XY sectional drawing of FIG. It is explanatory drawing explaining the manufacturing method of an ESD protection apparatus. It is sectional drawing which shows 2nd Embodiment of the ESD protection apparatus of this invention. It is explanatory drawing explaining the manufacturing method of an ESD protection apparatus. It is sectional drawing which shows 3rd Embodiment of the ESD protection apparatus of this invention. It is sectional drawing which shows 4th Embodiment of the ESD protection apparatus of this invention. It is sectional drawing which shows 5th Embodiment of the ESD protection apparatus of this invention.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a perspective view showing a first embodiment of an ESD protection apparatus of the present invention. 2 is an XZ sectional view of FIG. 3 is an XY cross-sectional view of FIG. As shown in FIGS. 1, 2, and 3, an ESD (Electro-Static Discharge) protection device 1 includes an element body 10, a first discharge electrode 21 provided in the element body 10, and a second discharge. The electrode 22 and the discharge auxiliary electrode 50, and the first external electrode 41 and the second external electrode 42 provided on the outer surface of the element body 10 are included.

  The element body 10 is formed in a substantially rectangular parallelepiped shape, and has a length, a width, and a height. The length direction of the element body 10 is the X direction, the width direction of the element body 10 is the Y direction, and the height direction of the element body 10 is the Z direction. The outer surface of the element body 10 includes a first end surface 10a, a second end surface 10b located on the opposite side of the first end surface 10a, and a peripheral surface 10c located between the first end surface 10a and the second end surface 10b. The first end surface 10a and the second end surface 10b are located in the X direction.

  The element body 10 is configured by laminating a plurality of ceramic layers 11. The plurality of ceramic layers 11 are stacked in the Z direction. The ceramic layer is made of, for example, low temperature co-fired ceramics (LTCC) containing Ba, Al, and Si as main components. The ceramic layer may contain at least one of an alkali metal component and a boron component, or may contain a glass component.

  The first discharge electrode 21 and the second discharge electrode 22 face each other in the stacking direction (Z direction) of the plurality of ceramic layers 11. The first discharge electrode 21 and the second discharge electrode 22 are arranged at a predetermined distance in the stacking direction. The first discharge electrode 21 is connected to the first external electrode 41, and the second discharge electrode 22 is connected to the second external electrode 42.

  The first discharge electrode 21 and the second discharge electrode 22 are each formed in a plate shape extending in the X direction. The first discharge electrode 21 and the second discharge electrode 22 are made of an appropriate material such as, for example, Cu, Ag, Pd, Pt, Al, Ni, W, or an alloy containing at least one of them.

  The first end 211 in the longitudinal direction of the first discharge electrode 21 is exposed from the first end face 10 a of the element body 10. The second end 212 in the longitudinal direction of the first discharge electrode 21 is located in the element body 10. The first end 221 in the longitudinal direction of the second discharge electrode 22 is exposed from the second end face 10 b of the element body 10. The second end 222 in the longitudinal direction of the second discharge electrode 22 is located in the element body 10. The second end 212 of the first discharge electrode 21 and the second end 222 of the second discharge electrode 22 face each other with a predetermined distance.

  The auxiliary discharge electrode 50 is provided between the first discharge electrode 21 and the second discharge electrode 22 and electrically connects the first discharge electrode 21 and the second discharge electrode 22. The discharge auxiliary electrode 50 connects the second end 212 of the first discharge electrode 21 and the second end 222 of the second discharge electrode 22.

  The discharge auxiliary electrode 50 includes a first surface direction electrode portion 51 connected to the first discharge electrode 21 and a counter direction electrode portion 60 connected to the first surface direction electrode portion 51.

  The first surface direction electrode portion 51 is provided on the surface of the first discharge electrode 21 that faces the second discharge electrode 22, and extends in the surface direction of the first discharge electrode 21. The first surface direction electrode portion 51 is formed in a rectangular shape when viewed from the stacking direction.

  The counter direction electrode part 60 extends in the counter direction (stacking direction) of the first discharge electrode 21 and the second discharge electrode 22. The counter-direction electrode unit 60 is disposed in the via hole 12 penetrating in the stacking direction of the element body 10 between the first discharge electrode 21 and the second discharge electrode 22. The counter direction electrode part 60 is formed in a truncated cone. The height direction of the truncated cone coincides with the stacking direction. The bottom surface of the truncated cone contacts the first discharge electrode 21, and the upper surface of the truncated cone contacts the second discharge electrode 22. The bottom surface of the truncated cone is smaller than the top surface of the truncated cone.

  The first surface direction electrode portion 51 has a contact surface 51 a that contacts the first discharge electrode 21. The contact surface 51a is formed in a rectangular shape. The facing direction electrode part 60 has a contact surface 60 a that contacts the first surface direction electrode part 51. The contact surface 60a is formed in a circular shape. The contact surface 51 a of the first surface direction electrode unit 51 is larger than the contact surface 60 a of the counter direction electrode unit 60. All of the contact surfaces 60a of the counter-direction electrode unit 60 overlap the contact surfaces 51a of the first surface-direction electrode unit 51 when viewed from the stacking direction.

The discharge auxiliary electrode 50 is composed of, for example, a mixture of a conductive material and an insulating material. The conductive material is, for example, a conductor powder. The conductive material may be, for example, Cu, Ag, Pd, Pt, Al, Ni, W, or a combination thereof, and may be a material having lower conductivity than a metal material such as a semiconductor material such as SiC powder or a resistance material. There may be. Insulating materials include, for example, oxides such as Al ₂ O ₃ , SiO ₂ , ZrO ₂ , TiO ₂ , nitrides such as Si ₃ N ₄ and AIN, mixed calcined powders of constituent materials of ceramic substrates, glass Substances or combinations thereof may be used.

  The content ratio of the conductive material of the first surface direction electrode portion 51 may be the same as or different from the content ratio of the conductive material of the counter direction electrode portion 60. Preferably, the content ratio of the conductive material of the first surface direction electrode portion 51 may be larger than the content ratio of the conductive material of the counter direction electrode portion 60.

  The first external electrode 41 covers the entire first end surface 10a and covers the end portion of the peripheral surface 10c on the first end surface 10a side. The first external electrode 41 is in contact with and electrically connected to the first end 211 of the first discharge electrode 21. The second external electrode 42 covers all of the second end surface 10b and covers the end portion of the peripheral surface 10c on the second end surface 10b side. The second external electrode 42 is in contact with and electrically connected to the first end 221 of the second discharge electrode 22. The first external electrode 41 and the second external electrode 42 are made of, for example, an appropriate material such as Cu, Ag, Pd, Pt, Al, Ni, W, or an alloy containing at least one of them.

  Next, a method for manufacturing the ESD protection device 1 will be described.

  As shown in FIG. 4, the first ceramic sheet 111 is provided with a via hole 12 that penetrates the first surface 111a and the second surface 111b. The counter-direction electrode unit 60 is filled in the via hole 12. The 1st surface direction electrode part 51 is printed on the bottom face of the counter direction electrode part 60, and a part of 1st surface 111a. The 1st discharge electrode 21 is printed on the whole surface of the 1st surface direction electrode part 51, and a part of 1st surface 111a. The second discharge electrode 22 is printed on a part of the second surface 111b.

  Thereafter, the second ceramic sheet 112 is laminated on the first surface 111 a of the first ceramic sheet 111, and the third ceramic sheet 113 is laminated on the second surface 111 b of the first ceramic sheet 111. Then, after providing the 1st, 2nd external electrodes 21 and 22 in the end surface of the laminated | stacked 1st-3rd ceramic sheets 111-113, the whole is baked and the ESD protection apparatus 1 is manufactured.

  Next, the operation of the ESD protection device 1 will be described.

  The ESD protection apparatus 1 is used in, for example, an electronic device, and discharges static electricity generated in the electronic device to suppress destruction of the electronic device due to static electricity. More specifically, when the first external electrode 41 is connected to the terminal (primary side) of the electronic device and the second external electrode 42 is connected to the ground (secondary side), the static electricity of the electronic device is the first It is transmitted from the external electrode 41 and the first discharge electrode 21 to the second discharge electrode 22 and the second external electrode 42 via the discharge auxiliary electrode 50. The primary side is the side where static electricity is input, and the secondary side is the side where static electricity is output. The electrostatic discharge from the first discharge electrode 21 to the second discharge electrode 22 is a discharge due to a current flowing inside the auxiliary discharge electrode 50.

  According to the ESD protection device 1, when the discharge auxiliary electrode 50 and the first discharge electrode 21 are subjected to thermal shock during ESD application, the coefficient of thermal expansion of the discharge auxiliary electrode 50 and the coefficient of thermal expansion of the first discharge electrode 21 are different. Therefore, thermal stress is generated on the contact surface 51a of the auxiliary discharge electrode 50 with the first discharge electrode 21. Here, since the contact surface 51a of the first surface direction electrode portion 51 is larger than the contact surface 60a of the counter direction electrode portion 60, the area of the contact surface 51a of the discharge auxiliary electrode 50 is larger than that of the related art.

  Therefore, the connection strength between the discharge auxiliary electrode 50 and the first discharge electrode 21 is improved, and the thermal stress is distributed over the entire contact surface 51a. Then, peeling (delamination) between the discharge auxiliary electrode 50 and the first discharge electrode 21 due to local concentration of thermal stress is prevented, and resistance to ESD application is improved.

  On the other hand, when the discharge auxiliary electrode 50 does not have the first surface direction electrode portion 51 but has only the counter direction electrode portion 60 as in the conventional case, the contact surface 60a of the counter direction electrode portion 60 is increased. The material of the discharge auxiliary electrode 50 is wasted. In short, in the present invention, only the portion necessary for improving resistance is enlarged.

  According to the ESD protection device 1, the area of the contact surface 51 a of the discharge auxiliary electrode 50 is increased in a state where the first discharge electrode 21 is connected to the primary side. The connection of the electrode 21 is improved, and the ESD response is improved. In addition, since the area of the contact surface 51a of the auxiliary discharge electrode 50 is increased, the electric field concentration on the first surface direction electrode portion 51 is increased and discharge is easily performed.

  According to the ESD protection device 1, the content ratio of the conductive material in the first surface direction electrode portion 51 may be larger than the content ratio of the conductive material in the counter direction electrode portion 60. At this time, the concentration of the electric field on the first surface direction electrode portion 51 is increased, and the discharge becomes easy. Therefore, the discharge start voltage can be lowered and the ESD response can be improved. Furthermore, since the discharge start voltage can be lowered, resistance to ESD application is improved.

  Moreover, the electroconductivity of the 1st surface direction electrode part 51 can be made high, and the discharge property can be given to the 1st surface direction electrode part 51. FIG. On the other hand, the conductivity of the counter direction electrode portion 60 can be lowered, and the counter direction electrode portion 60 can be provided with insulation. Therefore, the discharge function of the first surface direction electrode part 51 and the insulating function of the counter direction electrode part 60 can be separated.

(Second Embodiment)
FIG. 5 is a sectional view showing a second embodiment of the ESD protection apparatus of the present invention. The second embodiment is different from the first embodiment in the configuration of the discharge auxiliary electrode. This different configuration will be described below. Note that in the second embodiment, the same reference numerals as those in the first embodiment have the same configurations as those in the first embodiment, and a description thereof will be omitted.

  As shown in FIG. 5, the discharge auxiliary electrode 50 </ b> A of the ESD protection apparatus 1 </ b> A includes a second surface direction electrode portion 52 in addition to the first surface direction electrode portion 51 and the counter direction electrode portion 60 of the first embodiment. The second surface direction electrode part 52 is connected between the counter direction electrode part 60 and the second discharge electrode 22.

  The second surface direction electrode portion 52 is provided on the surface of the second discharge electrode 22 that faces the first discharge electrode 21, and extends in the surface direction of the second discharge electrode 22. The second surface direction electrode portion 52 is formed in a rectangular shape when viewed from the stacking direction.

  The second surface direction electrode portion 52 has a contact surface 52 a that contacts the second discharge electrode 22. The contact surface 52a is formed in a rectangular shape. The counter direction electrode part 60 has a contact surface 60 b that contacts the second surface direction electrode part 52. The contact surface 60b is formed in a circular shape. The contact surface 52 a of the second surface direction electrode portion 52 is larger than the contact surface 60 b of the counter direction electrode portion 60. All of the contact surfaces 60 b of the counter direction electrode portion 60 overlap the contact surfaces 52 a of the second surface direction electrode portion 52 when viewed from the stacking direction.

  Next, a method for manufacturing the ESD protection apparatus 1A will be described.

  As shown in FIG. 6, the first ceramic sheet 111 is provided with a via hole 12 that penetrates the first surface 111a and the second surface 111b. The counter-direction electrode unit 60 is filled in the via hole 12. The 1st surface direction electrode part 51 is printed on the bottom face of the counter direction electrode part 60, and a part of 1st surface 111a. The 1st discharge electrode 21 is printed on the whole surface of the 1st surface direction electrode part 51, and a part of 1st surface 111a.

  The second discharge electrode 22 is printed on a part of one surface of the third ceramic sheet 113. The second surface direction electrode portion 52 is printed on a part of the second discharge electrode 22.

  Thereafter, the second ceramic sheet 112 is laminated on the first surface 111 a of the first ceramic sheet 111, and the third ceramic sheet 113 is laminated on the second surface 111 b of the first ceramic sheet 111. At this time, the second surface direction electrode portion 52 is brought into contact with the upper surface of the counter direction electrode portion 60.

  Then, after providing the 1st, 2nd external electrodes 21 and 22 in the end surface of the laminated | stacked 1st-3rd ceramic sheets 111-113, the whole is baked and ESD protection apparatus 1A is manufactured.

  According to the ESD protection apparatus 1A, in addition to the effects of the first embodiment, the contact surface 52a of the second surface direction electrode portion 52 is larger than the contact surface 60b of the counter direction electrode portion 60. The area of the contact surface 52a with the 50A second discharge electrode 22 is larger than the conventional area. Therefore, the connection strength between the auxiliary discharge electrode 50A and the second discharge electrode 22 is improved. Thereby, peeling between 50 A of discharge auxiliary electrodes and the 2nd discharge electrode 22 is prevented, and the tolerance with respect to ESD application improves.

(Third embodiment)
FIG. 7 is a cross-sectional view showing a third embodiment of the ESD protection apparatus of the present invention. The third embodiment is different from the first embodiment in the configuration of the discharge auxiliary electrode. This different configuration will be described below. Note that in the third embodiment, the same reference numerals as those in the first embodiment have the same configurations as those in the first embodiment, and a description thereof will be omitted.

  As illustrated in FIG. 7, the discharge auxiliary electrode 50 </ b> B of the ESD protection apparatus 1 </ b> B includes a plurality (three in the third embodiment) of counter direction electrode portions 60. The first surface direction electrode portion 51 has a contact surface 51 a that contacts the first discharge electrode 21. The facing direction electrode part 60 has a contact surface 60 a that contacts the first surface direction electrode part 51.

  The contact surface 51 a of the first surface direction electrode portion 51 is larger than the contact surfaces 60 a of all the counter direction electrode portions 60. The contact surfaces 60a of all the counter-direction electrode portions 60 overlap the contact surfaces 51a of the first surface-direction electrode portions 51 when viewed from the stacking direction.

  According to the ESD protection apparatus 1B, the discharge auxiliary electrode 50B has the plurality of counter-direction electrode units 60. Therefore, even if one counter-direction electrode unit 60 stops operating, the other counter-direction electrode unit 60 operates. Therefore, it is possible to prevent the deterioration of responsiveness during ESD application.

(Fourth embodiment)
FIG. 8 is a sectional view showing a fourth embodiment of the ESD protection apparatus of the present invention. The fourth embodiment is different from the second embodiment in the configuration of the discharge auxiliary electrode. This different configuration will be described below. In addition, in 4th Embodiment, since the code | symbol same as 2nd Embodiment is the same structure as 2nd Embodiment, the description is abbreviate | omitted.

  As shown in FIG. 8, the discharge auxiliary electrode 50 </ b> C of the ESD protection apparatus 1 </ b> C is a counter-direction electrode different from the configuration of the second embodiment in addition to the first and second surface direction electrode portions 51 and 52 of the second embodiment. Part 60C.

  The counter-direction electrode portion 60C includes a first electrode portion 61 on the first discharge electrode 21 side and a second electrode portion 62 on the second discharge electrode 22 side. That is, the counter-direction electrode unit 60C is divided into two counter-direction electrode units 60 according to the second embodiment to form first and second electrode units 61 and 62. The first and second electrode portions 61 and 62 are disposed in the via holes 12 of the different ceramic layers 11, respectively.

  The third surface direction electrode unit 53 is connected between the first electrode unit 61 and the second electrode unit 62. The third surface direction electrode portion 53 extends in a surface direction that intersects the opposing direction of the first discharge electrode 21 and the second discharge electrode 22. That is, the third surface direction electrode portion 53 extends in the XY plane direction intersecting with the Z direction (stacking direction). The third surface direction electrode portion 53 is parallel to the first and second surface direction electrode portions 51 and 52 and has the same shape. The third surface direction electrode portion 53 is larger than the facing direction electrode portion 60C when viewed from the Z direction.

  According to the ESD protection apparatus 1 </ b> C, the third surface direction electrode portion 53 is connected between the first electrode portion 61 and the second electrode portion 62, so that the third surface direction electrode portion 53 bites into the element body 10. It is possible to prevent peeling between the auxiliary discharge electrode 50C and the element body 10.

(Fifth embodiment)
FIG. 9 is a cross-sectional view showing a fifth embodiment of the ESD protection apparatus of the present invention. In the first embodiment, a single ESD protection device is shown, but in the fifth embodiment, a module type ESD protection device is shown. Note that in the fifth embodiment, the same reference numerals as those in the first embodiment have the same configurations as those in the first embodiment, and a description thereof will be omitted.

  As shown in FIG. 9, the ESD protection apparatus 1 </ b> D includes a plurality of sets of the first and second discharge electrodes 21 and 22 and the discharge auxiliary electrode 50 of the first embodiment inside the element body 10. A plurality of external electrodes 40 are provided on the outer surface of the element body 10, and the internal electrodes 30 are provided inside the element body 10. The internal electrode 30 is connected to the first and second discharge electrodes 21, 22, the discharge auxiliary electrode 50 and the external electrode 40. The integrated circuit 5 is mounted on the outer surface of the element body 10, and the integrated circuit 5 is connected to the external electrode 40.

  According to the ESD protection device 1C, the resistance against ESD application can be improved even in the module type ESD protection device 1D.

  The present invention is not limited to the above-described embodiment, and the design can be changed without departing from the gist of the present invention. For example, the feature points of the first to fifth embodiments may be variously combined.

  In the embodiment, the first discharge electrode and the second discharge electrode are provided inside the element body. However, at least one of the first discharge electrode and the second discharge electrode is provided outside the element body. Also good.

  In the embodiment, the first discharge electrode is connected to the primary side and the second discharge electrode is connected to the secondary side, but the first discharge electrode is connected to the secondary side and the second discharge The electrode may be connected to the primary side.

  In the said embodiment, although the opposing direction electrode part is divided | segmented into the 1st, 2nd electrode part, you may divide | segment into three or more electrode parts.

[First embodiment]
Next, examples of the manufacturing method of the first embodiment will be described.

(1) Preparation of ceramic sheet The ceramic material used for the ceramic sheet was a material (BAS material) having a composition centered on Ba, Al, and Si. Each raw material was prepared and mixed so as to have a predetermined composition, and calcined at 800 ° C to 1000 ° C. The obtained calcined powder was pulverized with a zirconia ball mill for 12 hours to obtain a ceramic powder. To this ceramic powder, an organic solvent such as toluene and echinene was added and mixed. Furthermore, a binder and a plasticizer were added and mixed to obtain a slurry. The slurry thus obtained was molded by a doctor blade method to obtain a ceramic sheet having a thickness of 10 μm and a thickness of 50 μm.

(2) Preparation of discharge electrode The electrode paste for forming a discharge electrode was produced. An electrode paste was obtained by adding a solvent to a binder resin composed of 80 wt% Cu powder having an average particle diameter of about 2 μm and ethyl cellulose, and stirring and mixing with three rolls.

(3) Preparation of discharge auxiliary electrode A mixed paste for forming the discharge auxiliary electrode was produced. A core / shell powder of Cu / Al203 having an average particle diameter of about 2 μm and a silicon carbide powder having an average particle diameter of 0.5 μm are mixed at a ratio of 50/50 vol%, a binder resin and a solvent are added, and three rolls are used. A mixed paste was obtained by stirring and mixing. In the mixed paste, a binder resin composed of ethyl cellulose or the like and a solvent were 20 wt%, and the remaining 80 wt% was coated Cu powder and silicon carbide powder.

(4) Formation of via hole A via hole having a diameter of 100 μm was formed on the ceramic sheet by machining or laser processing. There may be a plurality of via holes. By providing a plurality of via holes, even if one counter-direction electrode unit does not operate, the other counter-direction electrode unit operates, so that it is possible to prevent responsiveness deterioration during ESD continuous application. Further, since the thickness of the ceramic sheet becomes a discharge gap, the ESD response is improved as the thickness of the ceramic sheet is reduced. This time, a 10 μm sheet was used.

(5) Formation of discharge auxiliary electrode (opposite direction electrode part) in stacking direction The counter direction electrode part of the discharge auxiliary electrode was filled in the via hole, and then dried to form the counter direction electrode part.

(6) Formation of Auxiliary Discharge Electrode (Surface Direction Electrode Part) in the Surface Direction The surface direction electrode part of the discharge auxiliary electrode was applied on the via hole with an area larger than the via hole diameter by screen printing. This time, filling in the via hole and printing in the surface direction are performed in separate processes, but they may be performed collectively by screen printing. When the planar electrode portion is arranged on the primary side where the ESD is input, the electric field is easily concentrated on the discharge start side, and the ESD response is improved.

(7) Formation of discharge electrode The discharge electrode connected to the external electrode was applied by screen printing. The discharge electrode may be directly connected to the external electrode, may be connected via a via hole, or may be connected to a circuit pattern or an integrated circuit.

(8) Lamination and pressure bonding Ceramic sheets were stacked and pressure bonded. Here, lamination was performed so that the discharge auxiliary electrode was disposed at the center with a thickness of 0.3 mm.

(9) Cut and External Electrode Formation Like a chip type electronic component such as an LC filter, it was cut with a micro cutter and divided into chips. Here, it cut so that it might become 1.0 mm x 0.5 mm. Thereafter, an electrode paste was applied to the end face of the chip to form an external electrode. The external electrode may be formed by applying and baking an electrode paste on the end face of the chip after the chip is fired.

(10) Firing Next, firing was performed in an N2 atmosphere. In the case of an electrode material (such as Ag) that does not oxidize, an air atmosphere may be used.

(11) Plating As with chip-type electronic components such as LC filters, electrolytic Ni—Sn plating was performed on the external electrodes.

(12) Completion The ESD protection device was completed as described above. In addition, the ceramic material used for the ceramic sheet is not particularly limited to the above-described materials, but Al2O3, cordierite, mullite, foresterite, LTCC material obtained by adding glass or the like to CaZrO3, Al2O3, cordierite, HTCC materials such as mullite and forest light, ferrite materials, dielectric materials, and resin materials may be used.

  In addition to Cu, the material of the discharge electrode may be Ag, Pd, Pt, Al, Ni, W, or a combination thereof, but Cu and Ag having high thermal conductivity are desirable.

  The discharge auxiliary electrode may be a single particle or a combination of conductors and semiconductors, or a combination of conductors, semiconductors, and insulator particles. The conductor particles may have a core-shell structure, a non-core-shell structure, or a combination of both. By adding particles having a core-shell structure having an insulator shell with a nanometer thickness, insulation resistance can be maintained without impairing ESD responsiveness. Further, the insulation resistance is further improved by interposing the glass or resin as a binder between the particles.

[Second Embodiment]
Next, examples of the manufacturing method of the second embodiment will be described.

  First, (1) to (5) of the first example were performed.

(6) Formation of Auxiliary Discharge Electrode (Surface Direction Electrode Section) in the Surface Direction As shown in FIG. 6, the surface direction electrode portion of the discharge auxiliary electrode screen-printed on the via hole and the screen-printed discharge on another ceramic sheet The surface direction electrode part of the auxiliary electrode was stacked. Since discharge auxiliary electrodes are disposed on the upper and lower surfaces of the via hole, ESD response can be obtained regardless of the ESD application direction. For this reason, it is not necessary to give directionality to the chip, the manufacturing cost can be reduced, and the design can be given flexibility.

  In addition, by arranging the planar electrode portions on both the upper and lower sides of the via hole, the difference in thermal contraction and thermal expansion coefficient between the discharge electrode and the discharge auxiliary electrode is reduced as compared with the arrangement on one side, and the discharge auxiliary electrode and the discharge electrode are reduced. Delamination is eliminated, the connection is improved, and the ESD response is improved. Further, the difference in thermal expansion coefficient between the discharge electrode and the ceramic layer and the discharge auxiliary electrode when thermal shock is applied during ESD application is reduced, crack generation is suppressed, and ESD continuous application resistance is improved.

  In addition, this time, the ceramic layer provided with the counter direction electrode portion has a single layer structure having a thickness of 10 μm. However, as in the third embodiment, the counter direction electrode portion is divided into two in the stacking direction. As the second electrode portion, the ceramic layer provided with the first electrode portion and the ceramic layer provided with the second electrode portion may be separate layers having a thickness of 5 μm. Thus, by making the ceramic layer which provides a counter direction electrode part into two layers, the difference of the thermal expansion coefficient of a discharge electrode and a ceramic layer, and a discharge auxiliary electrode is further relieve | moderated, and ESD continuous application tolerance improves.

  Then, (9)-(11) of 1st Example was performed and the ESD protection apparatus was completed.

(Experimental result)
Next, Table 1 shows the characteristic results of the conventional structure and the first and second embodiments. The discharge response to ESD was evaluated for 20 samples of the ESD protection device. Responsiveness to ESD was performed by an electrostatic discharge immunity test defined in IEC standard, IEC61000-4-2.

  As shown in Table 1, 2, 3, 4, 5, and 6 kV were applied by contact discharge, and the ESD applied voltage at which discharge was started was used as the discharge start voltage. 8kV is performed 100 times, 200 times, 300 times, and 500 times by contact discharge, and when the peak voltage detected on the protection circuit side exceeds 700V, the discharge response is poor (x mark), and the peak voltage is 500V. Discharge responsiveness is acceptable for those with ~ 700V (Δ mark), discharge responsiveness is good for those with a peak voltage of 300V to 500V (◯), and discharge responsiveness is particularly good for those with a peak voltage of less than 300V (◎).

  Reference numeral 1 indicates a conventional structure, and reference numerals 2-9 indicate the present invention. As can be seen from Table 1, by arranging the surface electrode portion, the amount of the discharge auxiliary electrode around the outer peripheral edge of the via hole where the electric field is concentrated when ESD is applied increases, and the electric field is more easily concentrated and the ESD discharge starts. The voltage is lowered.

  In addition, by making the number of counter direction electrode parts plural, even if one counter direction electrode part stops operating, the other counter direction electrode part operates, so that the ESD continuous voltage is maintained while maintaining the discharge start voltage. Application tolerance can be improved.

  In addition, by disposing the surface direction electrode portions on the upper and lower sides (primary side and secondary side) of the via hole, the thermal contraction difference and the thermal expansion coefficient difference between the discharge electrode and the discharge auxiliary electrode can be reduced compared to the one side arrangement. Further relax. This eliminates the delamination between the discharge auxiliary electrode and the discharge electrode, improves the connection, and improves the ESD response. Further, the difference in thermal expansion coefficient between the discharge electrode and the ceramic layer and the discharge auxiliary electrode when thermal shock is applied during ESD application is reduced, crack generation is suppressed, and ESD continuous application resistance is improved.

  Further, when the counter-direction electrode portion is divided in the stacking direction, that is, when the ceramic layer provided with the counter-direction electrode portion is a plurality of layers, the difference in the thermal expansion coefficient between the discharge electrode and the ceramic layer and the discharge auxiliary electrode is reduced, and Continuous application resistance is improved.

[Third embodiment]
Next, in the first and second embodiments, an embodiment of the manufacturing method of the ESD protection device when the content ratio of the conductive material in the surface direction electrode portion is made larger than the content ratio of the conductive material in the counter direction electrode portion. explain.

  First, (1) and (2) of the first example were performed.

(3) Preparation of Discharge Auxiliary Electrode A mixed paste for forming the counter-direction electrode part filling the via hole was prepared. A core / shell powder of Cu / Al203 having an average particle diameter of about 2 μm and a silicon carbide powder having an average particle diameter of 0.5 μm are mixed at a ratio of 50/50 vol%, a binder resin and a solvent are added, and three rolls are used. A mixed paste was obtained by stirring and mixing. In the mixed paste, a binder resin composed of ethyl cellulose or the like and a solvent were 20 wt%, and the remaining 80 wt% was coated Cu powder and silicon carbide powder.

  A mixed paste for forming the plane direction electrode part was produced. A core / shell powder of Cu / Al203 having an average particle diameter of about 2 μm and a silicon carbide powder having an average particle diameter of 0.5 μm are mixed at a ratio of 70/30 vol%, a binder resin and a solvent are added, and three rolls are used. A mixed paste was obtained by stirring and mixing. In the mixed paste, a binder resin composed of ethyl cellulose or the like and a solvent were 20 wt%, and the remaining 80 wt% was coated Cu powder and silicon carbide powder.

  Then, (4)-(11) of 1st Example was performed and the ESD protection apparatus was completed.

(Experimental result)
Next, the characteristic results of the third example are shown in Table 2. Table 2 shows the same measurement conditions as in Table 1. Table 2 is different from Table 1 in that the content ratio of the conductive material in the surface direction electrode portion is larger than the content ratio of the conductive material in the counter direction electrode portion.

  As can be seen from Table 2, by increasing the content ratio of the conductive material in the plane direction electrode part to be larger than the content ratio of the conductive material in the counter direction electrode part, the electric field concentration on the discharge auxiliary electrode is increased and discharge is easily performed. Become. That is, in Table 2, the discharge start voltage is lower than in Table 1 (first and second examples). Thus, since the discharge start voltage is low, the ESD continuous application resistance is also improved.

DESCRIPTION OF SYMBOLS 1,1A-1D ESD protective device 10 Element body 11 Ceramic layer 12 Via hole 21 1st discharge electrode 22 2nd discharge electrode 41 1st external electrode 42 2nd external electrode 50, 50A-50C Discharge auxiliary electrode 51 1st surface direction electrode Part 51a Contact surface 52 Second surface direction electrode part 52a Contact surface 53 Third surface direction electrode part 60, 60C Opposing direction electrode part 60a Contact surface 60b Contact surface 61 First electrode part 62 Second electrode part

Claims (6)

With the body,
A first discharge electrode and a second discharge electrode provided on the element body and arranged to face each other;
A discharge auxiliary electrode provided between the first discharge electrode and the second discharge electrode and electrically connecting the first discharge electrode and the second discharge electrode;
The discharge auxiliary electrode is
A first surface direction electrode portion connected to the first discharge electrode and extending in a surface direction of the first discharge electrode;
An opposing direction electrode portion connected to the first surface direction electrode portion and extending in an opposing direction of the first discharge electrode and the second discharge electrode;
The contact surface that contacts the first discharge electrode of the first surface direction electrode portion is larger than the contact surface that contacts the first surface direction electrode portion of the counter direction electrode portion,
Wherein said contact surface in contact with the first surface direction electrode of the counter-direction electrode portion is smaller than the surface of the second discharge electrode side of the facing direction electrode portion, ESD protection device. The auxiliary discharge electrode has a second surface direction electrode portion connected between the counter direction electrode portion and the second discharge electrode and extending in a surface direction of the second discharge electrode,
2. The ESD protection according to claim 1, wherein a contact surface that contacts the second discharge electrode of the second surface direction electrode portion is larger than a contact surface that contacts the second surface direction electrode portion of the counter direction electrode portion. apparatus. The discharge auxiliary electrode has a plurality of said opposing direction electrode portion, ESD protection device according to claim 1 or 2. The ESD protection device according to any one of claims 1 to 3 , wherein a content ratio of the conductive material in the first surface direction electrode portion is larger than a content ratio of the conductive material in the counter direction electrode portion. Wherein the first discharge electrode is connected to the primary side, the second discharge electrode is connected to the secondary side, ESD protection device according to any one of claims 1 to 4. The counter-direction electrode part is
A first electrode portion on the first discharge electrode side;
A second electrode portion on the second discharge electrode side,
Between the second electrode portion and the first electrode portion, the third surface direction electrode portion extending in the plane direction crossing the facing direction is connected, to any one of claims 1 to 5 The ESD protection device as described.

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