Static electricity countermeasure component

Abstract

This static electricity countermeasure component comprises an element body, a first discharge electrode, a second discharge electrode, a first auxiliary electrode, and a second auxiliary electrode. The element body has a discharge cavity section therein. The first discharge electrode is embedded in the element body and has a first exposed section that is exposed to the discharge cavity section. The second discharge electrode is embedded in the element body 2 and has a second exposed section that is exposed to the discharge cavity section and faces the first exposed section with a gap therebetween. The first auxiliary electrode is embedded in the element body and is disposed on the opposite side of the second discharge electrode with respect to the first discharge electrode. The second auxiliary electrode is embedded in the element body and is disposed on the opposite side of the first discharge electrode with respect to the second discharge electrode.

Description

Anti-static parts

[0001] The present disclosure relates to an anti-static component for absorbing static electricity.

[0002] In recent years, ICs have become increasingly miniaturized and highly integrated to meet the demand for smaller, more powerful electronic devices such as mobile phones, but at the same time, their withstand voltage has decreased.Even small-energy surges, such as electrostatic discharge surges that occur when a human body comes into contact with the terminals of an electronic device, can cause IC breakdown or malfunction.

[0003] As a countermeasure, an anti-static component is installed between the wiring through which static electricity enters and the ground, bypassing the static electricity and suppressing the high voltage applied to the IC.An anti-static component has a high resistance value under normal conditions and does not allow electricity to flow, but when high voltage such as static electricity is applied, its resistance value drops and electricity is allowed to flow.

[0004] For example, the electrostatic protection component disclosed in Patent Document 1 listed below includes a ceramic body having a cavity, and a first discharge electrode and a second discharge electrode whose main surfaces face each other across a gap within the cavity.

[0005] WO 2009 / 069270

[0006] Generally, high-withstand ESD protection components have high ESD resistance but high discharge inception voltages. Therefore, even when high voltages such as static electricity are applied, the ESD protection component may not allow current to flow, and in that case, the current will flow to the IC.

[0007] An electrostatic discharge protector according to one aspect of the present disclosure includes an element body, a first discharge electrode, a second discharge electrode, a first auxiliary electrode, and a second auxiliary electrode. The element body has a discharge cavity therein. The first discharge electrode is embedded in the element body and has a first exposed portion exposed to the discharge cavity. The second discharge electrode is embedded in the element body and has a second exposed portion exposed to the discharge cavity and facing the first exposed portion across a gap. The first auxiliary electrode is embedded in the element body and is located on the opposite side of the first discharge electrode from the second discharge electrode. The second auxiliary electrode is embedded in the element body and is located on the opposite side of the second discharge electrode from the first discharge electrode.

[0008] According to the present disclosure, an ESD protection component with a low discharge start voltage can be obtained.

[0009] Fig. 1 is a cross-sectional view of an ESD protector according to an embodiment, Fig. 2 is a cross-sectional view of the ESD protector, and Fig. 3 is a perspective cross-sectional view (cross-sectional view taken along line X-X in Fig. 2) of the ESD protector.

[0010] ESD protection components according to embodiments will be described below with reference to the drawings. The figures described in the following embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components do not necessarily reflect the actual dimensional ratios. Furthermore, the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

[0011] In the drawings, the X-axis, Y-axis, and Z-axis are perpendicular to one another, but this is merely an example and is not intended to define the directions in which the ESD protector is used.

[0012] (Embodiment) (1) Basic Configuration of ESD Protector An ESD protector 1 will be described with reference to FIGS. 1 to 3. FIG.

[0013] The ESD protector 1 mainly comprises an element body 2 , and a first discharge electrode 3 and a second discharge electrode 4 embedded in the element body 2 .

[0014] The element body 2 is made of an insulating material and has an approximately rectangular parallelepiped outer shape, with an internal discharge cavity 21. The element body 2 is required to be undamaged even if a discharge occurs inside, and is made of ceramic that is highly resistant to heat and thermal shock. The longitudinal direction of the element body 2 is along the Y-axis, the lateral direction is along the X-axis, and the up-down direction is along the Z-axis.

[0015] A portion of the first discharge electrode 3 and a portion of the second discharge electrode 4 are exposed to the discharge cavity 21 and face each other at a predetermined distance in the Z-axis direction with the discharge cavity 21 interposed therebetween.

[0016] The ESD protector 1 further includes a first terminal electrode 5 and a second terminal electrode 6 electrically connected to the first discharge electrode 3 and the second discharge electrode 4, respectively. The first terminal electrode 5 and the second terminal electrode 6 are formed on both end surfaces of the element body 2 in the Y-axis direction.

[0017] The ESD protector 1 further includes a first auxiliary electrode 7 and a second auxiliary electrode 8 (described later).

[0018] (2) Detailed Configuration of ESD Protective Component (2-1) Element Body Element body 2 is made of a ceramic insulator containing, as a main component, at least one ceramic composition selected from alumina, forsterite, steatite, mullite, and cordierite. These insulators have a low relative dielectric constant of 10 or less, and can reduce the parasitic capacitance value between first discharge electrode 3 and second discharge electrode 4.

[0019] The discharge cavity 21 is a substantially rectangular parallelepiped cavity formed inside the element body 2, and when an overvoltage is applied, a discharge occurs in this cavity.

[0020] (2-2) Discharge Electrode The first discharge electrode 3 is embedded in the element body 2. The first discharge electrode 3 is thin and rectangular in plan view from the Z-axis direction. The first discharge electrode 3 is connected to the first terminal electrode 5 and extends from the first terminal electrode 5 in the Y-axis direction. The first discharge electrode 3 has a first exposed portion 31 exposed to the discharge cavity 21.

[0021] The second discharge electrode 4 is embedded in the element body 2. The second discharge electrode 4 is thin and rectangular in plan view from the Z-axis direction. The second discharge electrode 4 is connected to the second terminal electrode 6 and extends from the second terminal electrode 6 in the Y-axis direction. The second discharge electrode 4 has a second exposed portion 41 exposed to the discharge cavity 21.

[0022] The first exposed portion 31 and the second exposed portion 41 face each other with a gap in the Z-axis direction. More specifically, the first exposed portion 31 of the first discharge electrode 3 and the second exposed portion 41 of the second discharge electrode 4 are formed on the inner wall of the discharge cavity 21, one on the bottom surface and the other on the opposing ceiling surface, and face each other in the Z-axis direction.

[0023] The first discharge electrode 3 and the second discharge electrode 4 contain, for example, Au.

[0024] (2-3) Terminal Electrodes The first terminal electrode 5 and the second terminal electrode 6 are provided on the first end face 22 and the second end face 23, respectively, on opposite sides of the element body 2 in the Y-axis direction. The first terminal electrode 5 and the second terminal electrode 6 are made of a sintered mixture of Ag and resin. The surfaces of the first terminal electrode 5 and the second terminal electrode 6 are provided with a nickel plating layer and further with a tin plating layer.

[0025] (2-4) Auxiliary Electrode (2-4-1) Overview of Auxiliary Electrode The first auxiliary electrode 7 is embedded in the element body 2 and is disposed on the opposite side of the first discharge electrode 3 from the second discharge electrode 4. The first auxiliary electrode 7 is thin and rectangular in plan view from the Z-axis direction. The first auxiliary electrode 7 is connected to the first terminal electrode 5 and extends from the first terminal electrode 5 in the Y-axis direction. The first auxiliary electrode 7 extends in the Y-axis direction in cross-sectional view.

[0026] The second auxiliary electrode 8 is embedded in the element body 2 and is disposed on the opposite side of the second discharge electrode 4 from the first discharge electrode 3. The second auxiliary electrode 8 is thin and rectangular in plan view from the Z-axis direction. The second auxiliary electrode 8 is connected to the second terminal electrode 6 and extends from the second terminal electrode 6 in the Y-axis direction. The second auxiliary electrode 8 extends in the Y-axis direction in cross-sectional view.

[0027] The first auxiliary electrode 7 and the second auxiliary electrode 8 contain, for example, Au.

[0028] (2-4-2) Details of the Auxiliary Electrode The first auxiliary electrode 7 is disposed in a plan view so as to correspond to the first discharge electrode 3. In other words, the first auxiliary electrode 7 is disposed so as to overlap the entire first discharge electrode 3 in a plan view. In particular, it is preferable that the first auxiliary electrode 7 is disposed so as to overlap the first exposed portion 31 in a plan view.

[0029] The second auxiliary electrode 8 is disposed in a plan view so as to correspond to the second discharge electrode 4. In other words, the second auxiliary electrode 8 is disposed so as to overlap the entire second discharge electrode 4 in a plan view. In particular, the second auxiliary electrode 8 is preferably disposed so as to overlap the second exposed portion 41 in a plan view.

[0030] (2-4-3) Effect of Auxiliary Electrodes The provision of the first auxiliary electrode 7 and the second auxiliary electrode 8 as described above can suppress an increase in the capacitance of the ESD protector 1. As a result, loss during signal transmission can be suppressed.

[0031] The provision of the first auxiliary electrode 7 and the second auxiliary electrode 8 as described above reduces the discharge inception voltage of the ESD protector 1. The reason for this is that, compared to an example in which the first auxiliary electrode 7 and the second auxiliary electrode 8 are not provided, the provision of the first auxiliary electrode 7 and the second auxiliary electrode 8 increases the number of electric field lines in the space in the discharge cavity 21 where the first exposed portion 31 of the first discharge electrode 3 and the second exposed portion 41 of the second discharge electrode 4 face each other when a high voltage is applied, thereby increasing the electric field strength. As a result, the discharge inception voltage of the ESD protector 1 is reduced. Therefore, when a high voltage such as static electricity is applied, a current flows quickly through the ESD protector 1.

[0032] (3) Operation of the ESD Protection Component The first terminal electrode 5 is connected to the side where voltage is applied to the electronic component to be protected from overvoltage, and the second terminal electrode 6 is connected to the ground side. The connections may be reversed. In this state, when a normal voltage is applied, no discharge occurs between the first discharge electrode 3 and the second discharge electrode 4, which are separated by the discharge cavity 21, and electricity flows to the electronic component.

[0033] However, when an overvoltage is applied, a discharge occurs between the first discharge electrode 3 and the second discharge electrode 4, and at this time electricity due to the overvoltage flows through the ESD protection component 1, and no overvoltage is applied to the electronic component.

[0034] (Modifications) Modifications of the embodiment are listed below. The modifications described below can be applied in appropriate combination with the above embodiment.

[0035] In the embodiment, the first auxiliary electrode 7 and the second auxiliary electrode 8 are mechanically connected to the first terminal electrode 5 and the second terminal electrode 6, respectively. However, in the embodiment, the first auxiliary electrode 7 and the second auxiliary electrode 8 do not have to be mechanically connected to the first terminal electrode 5 and the second terminal electrode 6, respectively. In this case, the same effects as in the embodiment can be obtained.

[0036] (Aspects) This specification includes the following aspects.

[0037] An electrostatic discharge protector (1) according to a first aspect includes an element body (2), a first discharge electrode (3), a second discharge electrode (4), a first auxiliary electrode (7), and a second auxiliary electrode (8). The element body (2) has a discharge cavity (21) therein. The first discharge electrode (3) is embedded in the element body (2) and has a first exposed portion (31) exposed to the discharge cavity (21). The second discharge electrode (4) is embedded in the element body (2) and has a second exposed portion (41) exposed to the discharge cavity (21) and facing the first exposed portion (31) across a gap. The first auxiliary electrode (7) is embedded in the element body (2) and is positioned on the opposite side of the first discharge electrode (3) from the second discharge electrode (4). The second auxiliary electrode (8) is embedded in the element body (2) and is arranged on the opposite side of the second discharge electrode (4) from the first discharge electrode (3).

[0038] According to this aspect, the provision of the first auxiliary electrode (7) and the second auxiliary electrode (8) reduces the discharge start voltage of the ESD protector (1), so that when a high voltage such as static electricity is applied, a current flows quickly through the ESD protector (1).

[0039] In the electrostatic discharge protector (1) according to the second aspect, in the first aspect, the element body (2) further has a first end face (22) and a second end face (23). The electrostatic discharge protector (1) further includes a first terminal electrode (5) provided on the first end face (22) and connected to a first discharge electrode (3) and a first auxiliary electrode (7), and a second terminal electrode (6) provided on the second end face (23) and connected to a second discharge electrode (4) and a second auxiliary electrode (8).

[0040] According to this embodiment, the first auxiliary electrode (7) and the second auxiliary electrode (8) are connected to the first terminal electrode (5) and the second terminal electrode (6), respectively, so that the discharge start voltage of the ESD protector (1) is low, and therefore, when a high voltage such as static electricity is applied, a current flows quickly through the ESD protector (1).

[0041] REFERENCE SIGNS LIST 1 ESD protection component 2 Element body 3 First discharge electrode 4 Second discharge electrode 5 First terminal electrode 6 Second terminal electrode 7 First auxiliary electrode 8 Second auxiliary electrode 21 Discharge cavity 22 First end surface 23 Second end surface 31 First exposed portion 41 Second exposed portion

Claims

1. An electrostatic protection component comprising: an element body having an internal discharge cavity; a first discharge electrode embedded in the element body and having a first exposed portion exposed to the discharge cavity; a second discharge electrode embedded in the element body and having a second exposed portion exposed to the discharge cavity and facing the first exposed portion with a gap between them; a first auxiliary electrode embedded in the element body and positioned on the opposite side of the first discharge electrode to the second discharge electrode; and a second auxiliary electrode embedded in the element body and positioned on the opposite side of the second discharge electrode to the first discharge electrode.

2. The electrostatic protection component according to claim 1, wherein the base body further has a first end face and a second end face, and further comprises a first terminal electrode provided on the first end face and to which the first discharge electrode and the first auxiliary electrode are connected, and a second terminal electrode provided on the second end face and to which the second discharge electrode and the second auxiliary electrode are connected.

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