JP2016058183A - Static electricity countermeasure element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a static electricity countermeasure element excellent in durability against repeat discharge.SOLUTION: A static electricity countermeasure element has an insulating substrate, a first discharge electrode penetrating the insulating substrate in the thickness direction, a discharge induction part provided to cover the upper end face of the first discharge electrode, and a second discharge electrode provided on the discharge induction part. More preferably, the height of the first discharge electrode, in the thickness direction of the insulating substrate, is 25-200 μm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an anti-static element, and more particularly to an anti-static element useful for use in a high-speed transmission system or in combination with a common mode filter.

  In recent years, electronic devices have been rapidly reduced in size and performance. Also, transmission speeds are increased and used as typified by high-speed transmission systems such as antenna circuits for mobile phones, RF modules, USB 2.0 and USB 3.0, S-ATA2, and HDMI (registered trademark). The progress of driving voltage reduction of circuit elements is remarkable. With the miniaturization of electronic equipment and the lower drive voltage of circuit elements, the withstand voltage of electronic components used in electronic equipment decreases. Therefore, protection of electronic components from overvoltage typified by electrostatic pulses generated when the human body and terminals of the electronic device come into contact has become an important technical issue.

  Conventionally, in order to protect an electronic component from such an electrostatic pulse, a method of providing a laminated varistor between a line where static electricity enters and a ground is generally employed. However, since the multilayer varistor generally has a large capacitance, it becomes a factor that degrades signal quality when used in a high-speed transmission system. Therefore, development of an anti-static element with a small electrostatic capacity that can be applied to a high-speed transmission system is required.

  As an electrostatic countermeasure element with a low capacitance, a device having a pair of discharge electrodes and further disposing a discharge inducing portion mainly composed of a conductive inorganic material and an insulating inorganic material between the discharge electrodes has been proposed. Yes. This type of anti-static element is provided between a line where static electricity enters and the ground, like a laminated varistor. When an excessive voltage is applied, discharge occurs between the electrodes of the antistatic element, and the static electricity can be guided to the ground side.

  An anti-static element equipped with this type of so-called gap-type electrode has features such as a large insulation resistance, a small capacitance, and a good response. On the other hand, when a discharge occurs between the electrodes, stress and heat are generated, and the electrodes are broken, missing, and degenerated. Furthermore, destruction and omission occur in the discharge inducing portion. Thus, there has been a problem that durability is deteriorated by repeated discharge.

  Patent Document 1 discloses a static electricity countermeasure element having the following structure as a technique for stabilizing the static electricity suppressing effect. The structure includes a discharge inducing portion in which a pair of discharge electrodes are included in different planes, extend in the plane direction, and further, a conductive material is dispersed on the inner peripheral surface of the cavity between the discharge electrodes. Has a structure.

  Patent Document 2 discloses an electrostatic countermeasure element having the following structure. The structure is such that the first discharge electrode penetrating between the main surfaces of the insulating layer and the main surface of the first discharge electrode are connected to each other, are included in the same plane as the main surface, and extend in the planar direction. An anti-static element comprising a discharge inducing part and a second discharge electrode connected to the discharge inducing part is disclosed.

JP 2010-129320 A JP 2011-187439 A

  In the anti-static element described in Patent Document 1, when heat and stress are generated due to discharge, a loss due to electrode degeneration, a breakdown of a discharge inducing portion, and a loss occur, and thus there is a problem that durability against repeated discharge deteriorates. The reason is that the discharge electrode is flat and it is difficult to secure a sufficient thickness, and the discharge inducing portion has a sufficient thickness such that the conductive material is dispersed only on the inner peripheral surface of the cavity. It is expected that it is not.

  Further, in the anti-static element described in Patent Document 2, when heat and stress are generated due to discharge, the electrode and the discharge inducing portion are broken or missing, which causes a problem that durability against repeated discharge deteriorates. The reason for this is that the discharge inducing part is flat, so that a sufficient thickness cannot be ensured, and the connecting surface between the discharge electrode and the discharge inducing part is insufficient, so that the dischargeable range is small. Is done.

  The present invention has been made in view of such circumstances. And the objective is to provide the antistatic element excellent in durability with respect to repeated discharge.

  In order to solve the above-described problems, an antistatic element of the present invention covers an insulating substrate, a first discharge electrode penetrating the insulating substrate in a thickness direction, and an upper end surface of the first discharge electrode. It has the discharge induction part provided and the 2nd discharge electrode provided on the said discharge induction part, It is characterized by the above-mentioned.

  The inventors have measured the characteristics of the anti-static element configured as described above, and confirmed that the durability against repeated discharge is excellent.

  The height ΔT of the first discharge electrode in the thickness direction of the insulating substrate is preferably 25 μm or more and 200 μm or less.

  By setting ΔT to the above range, the first discharge electrode can be more reliably prevented from being lost, and therefore the durability against repeated discharge is further improved.

  It is preferable that the first discharge electrode has a columnar shape or a truncated cone shape, and the diameter ΔD of the upper end surface covered with the discharge inducing portion of the first discharge electrode is 40 μm or more and 250 μm or less.

  By setting ΔD within the above range, it is possible to more reliably prevent the first discharge electrode and the discharge inducing portion from being lost, thereby further improving durability against repeated discharge.

  ADVANTAGE OF THE INVENTION According to this invention, the antistatic element excellent in durability with respect to repeated discharge can be provided.

1 is a schematic cross-sectional view schematically showing an electrostatic protection element 100 of Example 1. FIG. 6 is a schematic cross-sectional view schematically showing a modification 101 of the anti-static element 100. FIG. 6 is a schematic cross-sectional view schematically showing a modification 102 of the anti-static device 100. FIG. 10 is a schematic cross-sectional view schematically showing a modification 103 of the static electricity countermeasure element 100. FIG. 6 is a schematic cross-sectional view schematically showing a modification 104 of the electrostatic protection element 100. FIG. 6 is a schematic cross-sectional view schematically showing an anti-static element 200 of Comparative Example 1. FIG. It is a circuit diagram in an electrostatic discharge test.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios. Further, the following embodiments are exemplifications for explaining the present invention, and are not intended to limit the present invention only to the embodiments.

  FIG. 1 is a schematic cross-sectional view schematically showing an antistatic element 100 of the present embodiment. The electrostatic protection element 100 includes an insulating substrate 11a, a first discharge electrode 12 that penetrates the insulating substrate 11a in the thickness direction, a discharge inducing portion 14 that covers the upper end surface of the first discharge electrode 12, and a discharge inducing device. A second discharge electrode 13 provided on the upper portion of the portion 14 and a connection conductor 15 electrically connected to the first discharge electrode 12 are provided. In the electrostatic protection element 100, discharge occurs between the upper end surface covered with the discharge inducing portion 14 of the first discharge electrode and the second discharge electrode 13 through the discharge inducing portion 14. Then, another insulating substrate 11 is provided so as to cover and sandwich the insulating substrate 11a, the first discharge electrode 12, the discharge inducing portion 14, the second discharge electrode 13, and the connection conductor 15.

  In the electrostatic protection element 100 configured as described above, the first discharge electrode has a sufficiently high height in the thickness direction of the insulating substrate. Therefore, even if the first discharge electrode due to discharge melts and breaks down and degenerates, the electrode is not completely lost. Moreover, since the upper end surface of the first discharge electrode is covered with the discharge inducing portion, a sufficient contact area between the first discharge electrode and the discharge inducing portion can be ensured. Therefore, since the dischargeable range can be widened, the entire discharge inducing portion range between the first and second discharge electrodes is not deteriorated or completely lost due to repeated discharge. From these facts, it is presumed that durability against repeated discharge was enhanced.

  As long as the insulating substrates 11 and 11a can support at least the discharge electrodes 12 and 13 and the discharge inducing portion 14, the size and shape thereof are not particularly limited.

Specific examples of the insulating substrates 11 and 11a include a low dielectric constant of 50 or less, preferably 20 or less, such as Al ₂ O ₃ , SiO ₂ , MgO, AlN, Mg ₂ SiO ₄ (forsterite). A ceramic substrate using the material can be mentioned.

  The upper end surface of the first discharge electrode 12 formed through the insulating substrate 11a in the thickness direction and the second discharge electrode 13 formed on the insulating substrate are opposed to each other with the discharge inducing portion 14 interposed therebetween. Are spaced apart from each other. In the present embodiment, the discharge electrodes 12 and 13 are disposed on the insulating laminate 11 with a gap distance ΔG. Here, the gap distance ΔG means the shortest distance between the pair of discharge electrodes 12 and 13.

  Examples of the material constituting the discharge electrodes 12 and 13 include at least one metal selected from Ni, Al, Fe, Cu, Ti, Cr, Au, Ag, Pd, and Pt, or alloys thereof. However, these are not particularly limited.

  The shape of the first discharge electrode 12 is not particularly limited, and examples thereof include a columnar shape, a frustum shape, and a structure in which a plurality of columnar and frustum-shaped electrodes are joined to each other. A cylindrical shape and a truncated cone shape are preferable. Moreover, a pad electrode etc. may be formed so that the upper end surface of a discharge electrode may be covered, and the collar protruded from the upper end surface may be formed.

  There are no particular restrictions on the dimensions of the first discharge electrode. The height ΔT of the first discharge electrode 12 in the thickness direction of the insulating substrate 11a is preferably 200 μm or less from the viewpoint of size reduction and height reduction. Moreover, it is preferable that it is 25 micrometers or more from a viewpoint of improving the durability with respect to repeated discharge more. The diameter ΔD of the upper end surface covered with the discharge inducing portion 14 of the first discharge electrode 12 is 250 μm or less from the viewpoint of lower capacitance in consideration of use in a high-speed transmission line. Is preferred. As ΔD increases, the overlapping area with the second discharge electrode 13 increases and the capacitance increases. As a result, signal quality can be degraded in the high-speed transmission line. Moreover, it is preferable that it is 40 micrometers or more from a viewpoint of improving the durability with respect to repeated discharge more. Note that ΔT and ΔD can be measured from, for example, a transmission X-ray observation image.

  FIG. 2 is a schematic cross-sectional view schematically showing a modification 101 of the electrostatic protection element 100. The anti-static element 101 has insulating substrates 11a and 11b and discharge electrodes 12 in which the end surfaces of electrodes 12a and 12b penetrating the insulating substrates 11a and 11b in the thickness direction are combined. Discharge induction part 14 which covers the upper end surface of penetration electrode 12a, discharge electrode 13 provided in the upper part of discharge induction part 14, and connecting conductor 15 electrically connected with penetration electrode 12b are provided. Then, another insulating substrate 11 is provided so as to cover and sandwich the insulating substrates 11a and 11b, the first discharge electrode 12, the discharge inducing portion 14, the second discharge electrode 13, and the connection conductor 15. .

  Thus, when the first discharge electrodes 12a and 12b overlap in the thickness direction of the insulating substrates 11a and 11b, the height ΔT in the thickness direction of the insulating substrate overlaps in the thickness direction of the insulating substrate. The sum of the heights of the electrodes.

  FIG. 3 is a schematic cross-sectional view schematically showing a modified example 102 of the electrostatic protection element 100. The electrostatic protection element 102 includes an insulating substrate 11a, an electrode 12a that penetrates the insulating substrate 11a in the thickness direction, and a first discharge electrode 12 that includes a pad electrode 16 that covers the upper end surface of the through electrode 12a. . Furthermore, a discharge inducing portion 14 covering the pad electrode 16, a second discharge electrode 13 provided on the top of the discharge inducing portion 14, and a connection conductor 15 electrically connected to the first discharge electrode 12 are provided. Then, another insulating substrate 11 is provided so as to cover and sandwich the insulating substrate 11a, the first discharge electrode 12, the discharge inducing portion 14, the second discharge electrode 13, and the connection conductor 15.

  As described above, when there is a protruding portion such as a brim with respect to the bus bar of the first discharge electrode 12 on the upper end surface covered with the discharge induction portion 14 of the first discharge electrode 12, the discharge induction portion 14 covers it. The diameter ΔD of the upper end surface is the distance between the intersections of the two bus bars and the upper end surface. At this time, ΔT is the sum of the heights of the through-electrode 12a and the pad electrode 16 in the thickness direction of the insulating substrate.

  FIG. 4 is a schematic cross-sectional view schematically showing a modification 103 of the static electricity countermeasure element 100. The anti-static element 103 includes insulating substrates 11a and 11b, first discharge electrodes 12, second discharge electrodes 13, and first discharge electrodes 12 penetrating the insulating substrates 11a and 11b in the thickness direction, respectively. A discharge inducing portion 14 that covers the end surface and covers the lower end surface of the second discharge electrode 13, a connection conductor 15 that is electrically connected to the first discharge electrode 12, and an electrical connection to the second discharge electrode 13 A connection conductor 17 is provided. Then, another insulating substrate 11 is provided so as to cover and sandwich the insulating substrates 11a and 11b, the first discharge electrode 12, the discharge inducing portion 14, the second discharge electrode 13, and the connection conductors 15 and 17. ing.

  FIG. 5 is a schematic cross-sectional view schematically showing a modification 104 of the static electricity countermeasure element 100. The electrostatic protection element 104 includes an insulating substrate 11a, a first discharge electrode 12 that penetrates the insulating substrate 11a in the thickness direction, a discharge inducing portion 14 that covers the upper end surface of the first discharge electrode 12, and a discharge inducing portion 14 The second discharge electrode 13 provided on the top of the first discharge electrode 13 and the connection conductor 15 electrically connected to the first discharge electrode 12 are provided. Then, another insulating substrate 11 is provided so as to cover and sandwich the insulating substrates 11a and 11b, the first discharge electrode 12, the discharge inducing portion 14, the second discharge electrode 13, and the connection conductor 15. . At this time, as a positional relationship between the first discharge electrode 12 and the second discharge electrode 13, when viewed from a direction perpendicular to the upper end surface of the first discharge electrode 12, the upper end surface of the first discharge electrode 12 and the second discharge electrode 13 The two discharge electrodes 13 are in a positional relationship with no overlap.

  The method of forming the first discharge electrode 12 is not particularly limited, but a method of forming a hole in the hole and penetrating the insulating substrate 11a in the thickness direction is generally used. A known method can be appropriately selected as the hole processing method. For example, the method of forming the hole which penetrates the insulating laminated body 11a by laser processing, punching processing, electric discharge processing, drilling processing, etching processing, etc. is mentioned. Furthermore, as a method for filling the formed hole with an electrode, a method such as printing, coating, transfer, electroplating, electroless plating, vapor deposition or sputtering can be used. In addition, a device in which one or more green sheets made of an insulator are formed by forming a through-hole by laser processing, punching processing, or the like and forming an electrode layer by screen printing is used. May be formed.

  The shape of the second discharge electrode 13 as shown in the embodiment of FIGS. 1 to 5 is not particularly limited, and may be formed in a rectangular shape, a comb shape, or a sawtooth shape. Further, like the first discharge electrode 12 as shown in the embodiment of FIG. 4, the electrode may be formed through the insulating substrate 11b, and the shape thereof is not particularly limited, and is a column shape, a frustum shape, or a plurality of shapes. A columnar or frustum-shaped electrode may have a structure in which end faces are combined.

  The formation method of the 2nd discharge electrode 13 as shown by embodiment of FIGS. 1-5 is not specifically limited, A well-known method can be selected suitably. Specifically, for example, there is a method of forming the second discharge electrode 13 having a desired thickness in the insulating substrate by coating, transferring, electrolytic plating, electroless plating, vapor deposition, sputtering, or the like.

  The relative positional relationship between the pair of discharge electrodes 12 and 13 as shown in the embodiment of FIGS. 1 to 5 is not particularly limited. Regarding the positional relationship, when viewed from the vertical direction with respect to the upper end surface of the first discharge electrode 12, for example, the entire upper end surface of the first discharge electrode 12 and the second discharge electrode 13 shown in FIG. There may be a case where there is an overlap, or a case where the upper end surface of the first discharge electrode 12 and the second discharge electrode 13 shown in FIG.

  In this embodiment, in the connection between the discharge electrodes 12, 13 and the terminal electrodes (not shown) formed on the surfaces of the insulating substrates 11, 11a, 11b, the discharge electrodes 13 and the connection conductors 15, 17 are directly connected to the terminal electrodes. There is no particular limitation, but the case is electrically connected to. For example, it may be connected to an element having another function such as a coil, a resistor, or a capacitor formed in the same laminate as the antistatic element of the present embodiment.

  In the present embodiment, the discharge inducing portion 14 is composed of a composite in which an insulating inorganic material and a conductive inorganic material are dispersed. Further, the discharge inducing portion 14 may include a void portion, and the void, the composite in which the insulating inorganic material and the conductive inorganic material are dispersed may coexist.

Specific examples of the insulating inorganic material constituting the discharge inducing portion 14 include, but are not limited to, metal oxides and metal nitrides such as AlN. In consideration of insulation and cost, Al ₂ O ₃ , SrO, CaO, BaO, TiO ₂ , SiO ₂ , ZnO, In ₂ O ₃ , NiO, CoO, SnO ₂ , Bi ₂ O ₃ , Mg ₂ SiO ₄ , V ₂ O ₅ , CuO, MgO, ZrO ₂ , Mg ₂ SiO ₄ , AlN, BN and SiC are preferable. These may be used alone or in combination of two or more. The insulating inorganic material may be formed as a uniform film or may be formed as an aggregate of particles, and its properties are not particularly limited. Among these, it is more preferable to use Al ₂ O ₃ , SiO ₂ , Mg ₂ SiO ₄ or the like from the viewpoint of imparting a high degree of insulation.

  In the case where the discharge inducing portion 14 includes a conductive inorganic material, specific examples of the conductive inorganic material include metals, alloys, metal carbides, metal borides and the like, but are not particularly limited thereto. In consideration of conductivity, C, Ni, Al, Fe, Cu, Ti, Cr, Au, Ag, Pd and Pt, or alloys thereof are preferable.

  The gap distance ΔG between the discharge electrodes 12 and 13 is determined by the thickness of the discharge inducing portion 14. ΔG may be appropriately set in consideration of desired discharge characteristics, and is not particularly limited, but is usually about 1 to 50 μm, and more preferably about 5 to 40 μm from the viewpoint of securing low voltage initial discharge. is there.

  The formation method of the discharge induction part 14 is not specifically limited, A well-known thin film formation method is applicable. From the viewpoint of easily obtaining a high-performance discharge inducing portion 14 with good reproducibility, a method of firing after applying the above-described mixture containing at least the insulating inorganic material and the conductive inorganic material is preferable. Hereinafter, a preferable method for forming the discharge inducing portion 14 will be described.

  A mixture containing at least an insulating inorganic material and a conductive inorganic material is prepared, and this mixture is formed on the upper end surface of the discharge electrode 12 by coating or printing, followed by firing. In addition, you may mix | blend various additives, such as a solvent and a binder, in the case of preparation of a mixture, or the application or printing of a mixture. Moreover, the treatment conditions at the time of baking are not particularly limited, but considering productivity and economy, it is preferably about 10 minutes to 5 hours at 500 to 1200 ° C. in an air atmosphere.

  The present invention can be variously modified without departing from the gist thereof, and is not limited to the first embodiment described above.

  Hereinafter, the present invention will be described based on further detailed examples, but the present invention is not limited to these examples.

(Example 1)
First, as the insulating substrate 11a, a material composed mainly of Al ₂ O ₃ and a glass component was formed into a sheet, and a green sheet having a thickness of 25 μm was prepared. Then, a CO ₂ laser was used for this green sheet, and a cylindrical through hole was formed in the thickness direction so that the diameter of the upper end surface was 125 μm. This cylindrical through hole was filled with Ag paste to obtain a first discharge electrode 12. Furthermore, Ag paste was printed on the upper end surface of the first discharge electrode 12 by screen printing so as to have a thickness of about 20 μm, and the connection electrode 15 connected to the external electrode was patterned. Further, Ag paste was printed on one surface of the same green sheet by screen printing so as to have a thickness of about 20 μm, and the second discharge electrode 13 was patterned. The length of the second discharge electrode 13 and the connection electrode 15 was 0.80 mm, and the width was 0.095 mm.

Next, the discharge inducing portion 14 was formed on the second discharge electrode 13 by the following procedure. First, 80 vol% of glass particles (manufactured by Nippon Yamamura Glass Co., Ltd., product number: ME13) containing SiO ₂ as a main component as an insulating inorganic material, and Ag particles having an average particle size of 1 μm as a conductive inorganic material (Mitsui Metal Mining Co., Ltd. Company product, product number: SPQ05S) was weighed to 20 vol%, and these were mixed to obtain a mixture. A lacquer was prepared by kneading ethyl cellulose resin as a binder and terpineol as a solvent so that the solid content ratio was 8 wt%. The obtained lacquer and the mixture were blended so that the solid content ratio was 60 vol%, and the mixture was kneaded to prepare a paste.
Subsequently, the precursor of the discharge induction part 14 was formed on the 2nd discharge electrode 13 by screen printing using the obtained discharge induction part paste. The thickness was 40 μm and the dimensions were 0.2 mm square.

  Next, the green sheet was laminated so that the end surface of the first discharge electrode 12 where the connection electrode 15 was not formed was covered with the mixture layer. Subsequently, the laminated body was produced by performing hot press. Thereafter, the obtained laminate was cut into a predetermined size and separated into pieces. Thereafter, the individualized laminate is subjected to heat treatment (debinding treatment) at 200 ° C. for 1 hour, and then heated at 10 ° C. per minute and held at 950 ° C. for 30 minutes in the atmosphere. Obtained. The gap distance ΔG between the discharge electrodes 12 and 13, which is the thickness of the discharge inducing portion 14 after firing, was 30 μm, and the pattern dimension was 0.15 mm square. The height ΔT of the first discharge electrode 12 was 20 μm, and the diameter ΔD of the upper end surface covered with the discharge inducing portion 14 was 100 μm. Further, the thickness of the second discharge electrode 13 and the connection electrode 15 was 15 μm. The length of the second discharge electrode 13 and the connection electrode 15 was 0.65 mm, and the width was 0.075 mm. Note that ΔG, ΔT, and ΔD were measured from transmission X-ray observation images.

  Thereafter, a terminal electrode mainly composed of Ag is formed so as to be connected to the outer peripheral ends of the discharge electrodes 12 and 13, and further, electrolytic Cu, Ni, and Sn plating are performed, so that the structure as shown in FIG. The antistatic element 100 of Example 1 was obtained.

(Example 2)
The static electricity shown in FIG. 1 is operated in the same manner as in Example 1 except that a frustoconical through hole is formed on a green sheet having a thickness of 30 μm by a CO ₂ laser so that the diameter of the upper end surface becomes 125 μm. The countermeasure element 100 was obtained. The height ΔT of the first discharge electrode 12 after firing was 25 μm, and the diameter ΔD of the upper end surface covered with the discharge inducing portion 14 was 100 μm.

(Example 3)
The static electricity shown in FIG. 1 is operated in the same manner as in Example 1 except that a frustoconical through-hole is formed on a 125 μm thick green sheet with a CO ₂ laser so that the diameter of the upper end surface becomes 125 μm. The countermeasure element 100 was obtained. The height ΔT of the first discharge electrode 12 after firing was 100 μm, and the diameter ΔD of the upper end surface covered with the discharge inducing portion 14 was 100 μm.

Example 4
The static electricity shown in FIG. 1 is operated in the same manner as in Example 1 except that a frustoconical through hole is formed on a green sheet having a thickness of 250 μm with a CO ₂ laser so that the diameter of the upper end surface becomes 125 μm. The countermeasure element 100 was obtained. The height ΔT of the first discharge electrode 12 after firing was 200 μm, and the diameter ΔD of the upper end surface covered with the discharge inducing portion 14 was 100 μm.

(Example 5)
The static electricity shown in FIG. 1 is operated in the same manner as in Example 1 except that a frustoconical through hole is formed on a green sheet having a thickness of 375 μm with a CO ₂ laser so that the diameter of the upper end surface becomes 125 μm. The countermeasure element 100 was obtained. The height ΔT of the first discharge electrode 12 after firing was 300 μm, and the diameter ΔD of the upper end surface covered with the discharge inducing portion 14 was 100 μm.

(Example 6)
The static electricity shown in FIG. 1 is operated in the same manner as in Example 1 except that a frustoconical through hole is formed on a 125 μm thick green sheet by a CO ₂ laser so that the diameter of the upper end surface is 25 μm. The countermeasure element 100 was obtained. The height ΔT of the first discharge electrode 12 after firing was 100 μm, and the diameter ΔD of the upper end surface covered with the discharge inducing portion 14 was 20 μm.

(Example 7)
The static electricity shown in FIG. 1 is operated in the same manner as in Example 1 except that a frustoconical through hole is formed on a 125 μm thick green sheet with a CO ₂ laser so that the diameter of the upper end surface is 50 μm. The countermeasure element 100 was obtained. The height ΔT of the first discharge electrode 12 after firing was 100 μm, and the diameter ΔD of the upper end surface covered with the discharge inducing portion 14 was 40 μm.

(Example 8)
The static electricity shown in FIG. 1 is operated in the same manner as in Example 1 except that a frustoconical through hole is formed on a 125 μm thick green sheet with a CO ₂ laser so that the diameter of the upper end surface is 250 μm. The countermeasure element 100 was obtained. The height ΔT of the first discharge electrode 12 after firing was 100 μm, and the diameter ΔD of the upper end surface covered with the discharge inducing portion 14 was 200 μm.

Example 9
The static electricity shown in FIG. 1 is operated in the same manner as in Example 1 except that a frustoconical through hole is formed on a 125 μm thick green sheet with a CO ₂ laser so that the diameter of the upper end surface is 315 μm. The countermeasure element 100 was obtained. The height ΔT of the first discharge electrode 12 after firing was 100 μm, and the diameter ΔD of the upper end surface covered with the discharge inducing portion 14 was 250 μm.

(Example 10)
The static electricity shown in FIG. 1 is operated in the same manner as in Example 1 except that a frustoconical through hole is formed on a 125 μm thick green sheet with a CO ₂ laser so that the diameter of the upper end surface is 375 μm. The countermeasure element 100 was obtained. The height ΔT of the first discharge electrode 12 after firing was 100 μm, and the diameter ΔD of the upper end surface covered with the discharge inducing portion 14 was 300 μm.

(Comparative Example 1)
The same paste as Example 1 was prepared for the Ag paste for discharge electrodes and the paste for discharge induction part. An Ag paste was printed on a green sheet having a thickness of 125 μm by screen printing so as to have a thickness of about 25 μm, and the first discharge electrode 12 was patterned. The pattern dimensions were 0.65 mm in length and 0.095 mm in width. Next, the discharge inducing portion paste was printed on the electrode so as to be 0.15 mm square, and the discharge inducing portion 14 was patterned. Further, Ag paste was printed on one surface of the same green sheet by screen printing so as to have a thickness of 20 μm, and the second discharge electrode 13 was patterned. The dimensions were 0.55 mm in length and 0.095 mm in width. Next, a green sheet was laminated so that the second discharge electrode 13 and the discharge inducing portion were in contact with each other. Subsequent steps were performed in the same manner as in Example 1 to obtain an electrostatic protection element 200 of Comparative Example 1 having a structure as shown in FIG. The height of the first discharge electrode 12 of the anti-static element obtained after firing was 20 μm, and the thickness of the second discharge electrode 13 was 15 μm. The first discharge electrode 12 had a length of 0.45 mm and a width of 0.075 mm. Further, the second discharge electrode 13 had a length of 0.65 mm and a width of 0.075 mm. Further, the dimension of the discharge inducing portion 14 was 0.15 mm square, and the area of the portion covered with the discharge inducing portion of the first discharge electrode was the same as in Examples 1-5.

(Comparative Example 2)
Except that the height of the first discharge electrode 12 after firing was 25 μm, the same operation as in Comparative Example 1 was performed to obtain an electrostatic protection element 200 of Comparative Example 2 having a structure as shown in FIG.

(Comparative Example 3)
Except that the height of the first discharge electrode 12 after firing was 100 μm, the same operation as in Comparative Example 1 was performed to obtain an electrostatic protection element 200 of Comparative Example 3 having a structure as shown in FIG.

<Electrostatic discharge test>
Next, the electrostatic discharge test was implemented about the static electricity countermeasure element of Examples 1-10 obtained as mentioned above and Comparative Examples 1-3 using the electrostatic test circuit shown in FIG. Tables 1 and 2 show the test results.

  This electrostatic discharge test was performed in accordance with a human body model (discharge resistance 330Ω, discharge capacity 150 pF, applied voltage 8 kV, contact discharge) based on the electrostatic discharge immunity test and noise test of the international standard IEC61000-4-2. Specifically, as shown in the electrostatic test circuit of FIG. 7, one terminal electrode of the electrostatic countermeasure element to be evaluated is grounded, and an electrostatic pulse applying unit is connected to the other terminal electrode, An electrostatic pulse was applied by bringing a discharge gun into contact with the application section. In the electrostatic discharge test, 100 samples were prepared, and the electrostatic discharge test was repeated 500 times at 8.0 kV each.

  An evaluation method related to the results of the discharge durability test will be described. When the Peak voltage after one discharge and 500 discharges was compared, a sample in which the difference in values did not change substantially within 10 V was determined as A evaluation. In addition, when the peak voltage after the first discharge was compared with that after the 500th discharge, the difference was larger than 10V, but the sample having the peak voltage after the 500th discharge of 500V or less was evaluated as B. Further, samples having a Peak voltage after 500 discharges greater than 500V and 600V or less were evaluated as C, and samples greater than 600V were evaluated as D.

  From Table 1, in the results of the discharge endurance test, the electrostatic countermeasure elements of Examples 1 to 10 have a relatively small difference in the peak voltage between the first discharge and the 500th discharge, and the increase in the peak voltage due to the 500th discharge. It can be seen that is also suppressed. Therefore, it was confirmed that these elements have a structure capable of preventing the deterioration of the static electricity suppressing effect against the destruction of the discharge electrode and the discharge inducing portion caused by 500 discharges. On the other hand, the electrostatic countermeasure elements of Comparative Examples 1 to 3 showed that the peak voltage after 500 discharges was larger than 600 V in the discharge durability test. From the above, the structure in which the discharge electrode penetrates the insulating substrate as in Examples 1 to 10 is more durable than the structure in which the discharge electrode is formed on the surface of the insulating substrate as in Comparative Examples 1 to 3. It turns out that it is excellent in.

  Further, from Examples 1 to 5 in Table 1, in the range where ΔT is smaller than 25 μm, the Peak voltage after 500 discharges is extremely larger than the Peak voltage after 1 discharge, and the Peak voltage value is also The value is larger than 500V. Therefore, it can be seen that the static electricity suppressing effect is greatly deteriorated by repeated discharge in the range where ΔT is smaller than 25 μm. On the other hand, it can be seen that there is almost no difference between the Peak voltage after one discharge and the Peak voltage after 500 discharges in the range where ΔT exceeds 200 μm. Therefore, when ΔT is 200 μm or more, it is expected to be saturated as an effect of preventing deterioration of the static electricity suppressing effect when repeatedly discharged.

  From Table 2, it can be seen that the static electricity control elements of Example 3 and Examples 6 to 10 have a relatively small difference in Peak voltage between the first discharge and the 500th discharge. In addition, an increase in the Peak voltage due to 500 discharges is suppressed. Therefore, it was confirmed that these elements have a structure capable of preventing the deterioration of the static electricity suppressing effect against the destruction of the discharge electrode and the discharge inducing portion caused by 500 discharges. In the range where ΔD is smaller than 40 μm, the Peak voltage after 500 discharges is extremely higher than the Peak voltage after one discharge, and the Peak voltage value is also larger than 500V. Therefore, it can be seen that the static electricity suppressing effect is greatly deteriorated by repeated discharge in the range where ΔD is smaller than 40 μm. On the other hand, it can be seen that there is almost no difference between the Peak voltage after one discharge and the Peak voltage after 500 discharges in the range where ΔD exceeds 250 μm. Therefore, in the range where ΔD exceeds 250 μm, it is expected to be saturated as an effect of preventing deterioration of the static electricity suppressing effect when repeatedly discharging.

  As described above, the anti-static element of the present invention is excellent in durability against repeated discharge, and can be widely and effectively used for electronic / electric devices including the same and various devices, facilities, systems, and the like including the devices. .

DESCRIPTION OF SYMBOLS 11, 11a, 11b Insulating substrate 12, 13 Discharge electrode 12a, 12b Electrode which penetrated insulating substrate 14 Discharge induction part 15, 17 Connection conductor 16 Pad electrode 100, 101, 102, 103, 104, 200 Antistatic element

Claims (3)

An insulating substrate;
A first discharge electrode penetrating the insulating substrate in the thickness direction;
A discharge inducing portion provided to cover an upper end surface of the first discharge electrode;
And a second discharge electrode provided on the discharge inducing portion.   2. The antistatic element according to claim 1, wherein a height of the first discharge electrode in a thickness direction of the insulating substrate is 25 μm or more and 200 μm or less.   The first discharge electrode has a columnar shape or a truncated cone shape, and a diameter of an upper end surface of the first discharge electrode covered with the discharge inducing portion is 40 μm or more and 250 μm or less. 1. An electrostatic countermeasure element according to 1.

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