JP2018185918A - Esd protection device and manufacturing method of esd protection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ESD protection device in which deterioration of an IR due to repetitive discharge is restrained.SOLUTION: An ESD protection device includes a ceramic base material 1 in which a cavity 2 having an inner wall including an inner bottom face 3 and an inner ceiling face 4 is formed, and formed of ceramic containing a glass component, a seal layer 5 formed on the inner wall of the cavity 2, a discharge auxiliary electrode 6 formed on the seal layer 5, and a first discharge electrode 7 and a second discharge electrode 8 formed on the discharge auxiliary electrode 6. When viewing a profile where the inner bottom face 3 and the inner ceiling face 4 of the cavity 2 appear simultaneously, bends 3a, 3b are formed on the inner bottom face 3 to project to the inner side of the cavity 2, bends 4a, 4b are formed on the inner ceiling face 4 to project to the inner side of the cavity 2, and a high back space 2H having a large height from the inner bottom face 3 to the inner ceiling face 4 is formed in the cavity 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ESD protection device, and more particularly to an ESD protection device in which deterioration of IR (Insulation Resistance) due to repeated discharge is suppressed.

  The present invention also relates to a method of manufacturing an ESD protection device suitable for manufacturing the ESD protection device of the present invention.

  A ceramic base material having a cavity portion formed therein, a seal layer formed on the inner wall of the cavity portion, a discharge auxiliary electrode formed on the seal layer, and a space above the discharge auxiliary electrode. An ESD protection device including the first discharge electrode and the second discharge electrode is disclosed in Patent Document 1 (WO2011 / 040435 A1).

  FIG. 23 shows an ESD protection device 1000 disclosed in Patent Document 1.

  The ESD protection device 1000 includes a ceramic substrate 101 formed of a ceramic containing a glass component. A cavity 102 is formed inside the ceramic substrate 101.

  A seal layer 103 is formed on the inner wall of the cavity 102. The seal layer 103 is formed in order to prevent the glass component included in the ceramic base material 101 from entering the cavity 102.

  An auxiliary discharge electrode 104 is formed on the seal layer 103 formed on the inner bottom surface of the cavity 102. Furthermore, a first discharge electrode (one side counter electrode) 105 and a second discharge electrode (the other side counter electrode) 106 are formed on the auxiliary discharge electrode 104 so as to face each other. The discharge auxiliary electrode 104 includes a conductive component, and is formed to promote discharge between the first discharge electrode 105 and the second discharge electrode 106.

  In the ESD protection device 1000, when a high voltage is applied between the first discharge electrode 105 and the second discharge electrode 106, a discharge is generated between the first discharge electrode 105 and the second discharge electrode 106.

WO2011 / 040435 A1

The ESD protection device 1000 has a problem that IR (Insulation Resistance) between the first discharge electrode 105 and the second discharge electrode 106 deteriorates when the discharge is repeated. Specifically, there is a case where IR that is 10 ¹⁰ Ω or more is lowered to less than 10 ⁴ Ω by repeating discharge.

  It is believed that IR degradation due to repeated discharge occurs by the following mechanism. That is, when a discharge occurs between the first discharge electrode 105 and the second discharge electrode 106, the inside of the sealed cavity 102 becomes extremely high. When the inside of the cavity 102 reaches a very high temperature, the conductive component contained in the discharge auxiliary electrode 104 is melted. The molten conductive component is solidified again as the temperature inside the cavity 102 decreases. However, as the discharge is repeated, the conductive component is conductive between the first discharge electrode 105 and the second discharge electrode 106 by the conductive component. It is considered that a path is formed and IR between the first discharge electrode 105 and the second discharge electrode 106 is lowered.

  As a method of suppressing the deterioration of IR due to repeated discharge, a method of increasing the volume of the cavity 102 and mitigating the rise in temperature inside the cavity 102 due to discharge can be considered.

  However, it is not easy to increase the volume of the cavity 102. That is, the cavity 102 of the ceramic substrate 101 is usually formed by the following method.

  First, one ceramic green sheet is prepared. Next, a seal paste is applied to the upper main surface of the ceramic green sheet to form a lower seal paste layer. Next, a discharge auxiliary electrode paste is applied on the lower seal paste layer to form a discharge auxiliary electrode paste layer. Next, a conductive paste is applied on the discharge auxiliary electrode paste layer to form a first discharge electrode paste layer and a second discharge electrode paste layer. Next, a cavity forming paste that disappears by firing is applied onto the discharge auxiliary electrode paste layer on which the first discharge electrode paste layer and the second discharge electrode paste layer are formed. Form. Next, a seal paste was applied on the cavity forming paste layer to form an upper seal paste layer, and the first discharge electrode paste layer and the second discharge electrode paste layer were each partially led to the outside. In the state, the lower seal paste layer and the upper seal paste layer surround the discharge auxiliary electrode paste layer, the first discharge electrode paste layer, the second discharge electrode paste layer, and the cavity forming paste layer. Next, the ceramic green sheet that has undergone these steps and another ceramic green sheet are laminated, pressed, and integrated to produce a green ceramic green sheet laminate. Finally, by firing the unfired ceramic green sheet laminate, the cavity forming paste disappears, and the ceramic substrate 101 having the cavity 102 formed therein is produced.

  It is not easy to increase the volume of the cavity 102 in the ceramic substrate 101 having the cavity 102 formed therein, which is manufactured by the above method. The reason will be described below.

  In order to increase the volume of the cavity portion 102, a thick cavity portion forming paste layer is formed on the discharge auxiliary electrode paste layer, and the height from the inner bottom surface to the inner top surface of the formed cavity portion. Should be increased. Specifically, the thickness of the cavity forming paste to be applied may be increased, or the cavity forming paste may be applied multiple times to form a cavity forming paste layer having a large thickness.

  However, when the thickness of the cavity forming paste layer is simply increased, the cavity 102 is supported by the cavity forming paste layer that disappears when the green ceramic green sheet laminate is fired. In some cases, the formed cavity 102 may be crushed, and the volume of the cavity 102 may be reduced. In particular, when the width of the cavity 102 is large, the formed cavity 102 may be crushed, and conversely, the volume of the cavity 102 may be reduced.

  Therefore, conventionally, it has been difficult to increase the volume of the cavity 102 and suppress the deterioration of IR due to repeated discharge.

  The present invention has been made in order to solve the above-described conventional problems, and as its means, the ESD protection device of the present invention has a hollow portion having an inner wall including at least an inner bottom surface and an inner top surface inside. The formed ceramic base material, the seal layer formed on the inner wall of the cavity, the discharge auxiliary electrode formed on the seal layer formed on the inner bottom surface of the cavity, and the gap above the discharge auxiliary electrode A first discharge electrode and a second discharge electrode formed to be open, and the inner bottom surface and the inner top surface of the cavity part appear at the same time. At least one of the pair of bent portions protruding to the inner side of the cavity portion is formed, and the inner bottom surface is formed between the pair of bent portions of the cavity portion rather than the outside of the pair of bent portions. A high-back space with a large height from the top to the inner ceiling was formed It was as.

  In this application document, for convenience of explanation, the terms of the inner bottom surface of the cavity and the inner top surface of the cavity are used. However, the ESD protection device of the present invention has the inner bottom surface of the cavity facing upward. In some cases, it is used with the inner top surface side of the cavity facing down.

  Each of the first discharge electrode and the second discharge electrode has a strip shape having a lower main surface, an upper main surface, a tip surface, one side surface, and the other side surface, and one of the first discharge electrodes The side surface and the one side surface of the second discharge electrode are arranged in parallel and opposite to each other, the one side surface of the first discharge electrode and the one side surface of the second discharge electrode arranged opposite to each other. A discharge gap can be formed. In this case, the width of the cavity portion tends to increase, but according to the present invention, the volume of the cavity portion can be increased while maintaining the shape of the cavity portion.

  Alternatively, each of the first discharge electrode and the second discharge electrode has a strip shape having a lower main surface, an upper main surface, a tip surface, one side surface, and the other side surface. The front end surface and the front end surface of the second discharge electrode are arranged to face each other, and a discharge gap is formed by the front end surface of the first discharge electrode and the front end surface of the second discharge electrode arranged to face each other. You may do it. Note that the tip surfaces of the first discharge electrode and the second discharge electrode are not necessarily formed by one surface, and may be formed by, for example, two surfaces and may have a pointed tip surface. Further, the tip surfaces of the first discharge electrode and the second discharge electrode may be circular or elliptical in plan view.

  In these cases, it is assumed that the front end surface, the one side surface, and the other side surface of the first discharge electrode and the second discharge electrode are at least partially exposed to the cavity. preferable. In this case, a cavity having a larger volume can be formed, and IR deterioration due to repeated discharge can be more effectively suppressed.

  A pair of bent portions are formed on the inner bottom surface of the hollow portion, and the first discharge electrode and the second discharge electrode are bent immediately above the bent portion formed on the inner bottom surface, respectively, It is also preferable that each of the second discharge electrodes falls to the inner bottom surface side in the high-back space portion. In this case, since a large space can be provided between the first discharge electrode and the second discharge electrode (discharge gap) that generates high heat during discharge, the inside of the cavity 102 due to discharge can be provided. An increase in temperature can be mitigated, and IR deterioration due to repeated discharge can be more effectively suppressed.

  The direction in which the first discharge electrode and the second discharge electrode extend and the direction in which the high-back space extends extend in parallel. Alternatively, the direction in which the first discharge electrode and the second discharge electrode extend may be perpendicular to the direction in which the high-back space portion extends. In either case, the volume of the cavity can be increased while maintaining the shape of the cavity.

  The ESD protection device manufacturing method of the present invention includes a step of preparing a plurality of ceramic green sheets, a seal paste is applied to a predetermined shape on an upper main surface of one ceramic green sheet, and a lower seal is formed. A step of forming a paste layer, a step of applying a discharge auxiliary electrode paste on the lower seal paste layer in a size smaller than that of the lower seal paste layer, and forming a discharge auxiliary electrode paste layer; Applying a conductive paste over the upper surface of the ceramic green sheet from above the electrode paste layer to form a first discharge electrode paste layer and a second discharge electrode paste layer each having a predetermined shape; On the auxiliary discharge electrode paste layer in which the first discharge electrode paste layer and the second discharge electrode paste layer are formed, the cavity portion shape disappears by firing. The step of applying the paste for forming the first cavity forming paste layer and the size of the first cavity forming paste layer smaller than the size of the first cavity forming paste layer disappear by firing And applying a sealing paste on the first cavity forming paste layer and the second cavity forming paste layer, and applying the cavity forming paste to form the second cavity forming paste layer In the state where the upper seal paste layer is formed and the first discharge electrode paste layer and the second discharge electrode paste layer are partially led to the outside, respectively, the lower seal paste layer and the upper seal paste layer, A step of surrounding the discharge auxiliary electrode paste layer, the first discharge electrode paste layer, the second discharge electrode paste layer, the first cavity forming paste layer, and the second cavity forming paste layer; Seal pace Layer, discharge auxiliary electrode paste layer, first discharge electrode paste layer, second discharge electrode paste layer, first cavity forming paste layer, second cavity forming paste layer, and upper seal paste layer And forming a green ceramic green sheet laminate by stacking, pressing and integrating the ceramic green sheet and the other ceramic green sheet, and forming the green ceramic green sheet laminate Firing, eliminating the first cavity portion forming paste layer and the second cavity portion forming paste layer, the ceramic substrate having the cavity portion formed therein, and the sealing layer formed on the inner wall of the cavity portion; An ESD protection device comprising a discharge auxiliary electrode formed on a seal layer and a first discharge electrode and a second discharge electrode formed on the discharge auxiliary electrode with a space therebetween is produced. The process was equipped with.

  In the step of forming the second cavity forming paste layer, for example, the direction in which the first discharge electrode paste layer and the second discharge electrode paste layer extend is parallel to the direction in which the second cavity forming paste layer extends. Thus, it is preferable to carry out by applying a cavity forming paste. Alternatively, the cavity forming paste is applied so that the direction in which the first discharge electrode paste layer and the second discharge electrode paste layer extend is perpendicular to the direction in which the second cavity forming paste layer extends. It is preferable. In any of the methods, a large volume cavity portion including a high-back space portion having a large height from the inner bottom surface to the inner top surface can be formed inside the ceramic base material.

  In addition, you may add the process of forming the paste layer for 3rd cavity part formation to the manufacturing method of the said ESD protection device. Furthermore, if necessary, a step of forming a cavity forming paste layer after the fourth cavity forming paste layer may be added.

  The ESD protection device according to the present invention has a high-back space portion in which the height from the inner bottom surface to the inner top surface is larger between the pair of bent portions of the hollow portion than the outside of the pair of bent portions. Is formed, the volume of the cavity is large. Therefore, in the ESD protection device of the present invention, the rise in temperature inside the cavity due to discharge is mitigated, and IR deterioration due to repeated discharge is suppressed.

  Moreover, according to the manufacturing method of the ESD protection device of this invention, the ESD protection device of this invention can be produced easily.

1A and 1B are cross-sectional views of the ESD protection device 100 according to the first embodiment, respectively. FIG. 2 is a cross-sectional view of the ESD protection device 100, which is an enlarged view of FIG. FIG. 3 is a plan view showing one process performed in an example of the method for manufacturing the ESD protection device 100. It is sectional drawing which shows the ESD protection device 1100 concerning a comparative example. 5A and 5B each show one process performed in an example of the manufacturing method of the ESD protection device 100, FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view. It is. 6A and 6B each show one process performed in an example of the manufacturing method of the ESD protection device 100, FIG. 6A is a plan view, and FIG. 6B is a cross-sectional view. It is. 7A and 7B each show one process performed in an example of a method for manufacturing the ESD protection device 100, FIG. 7A is a plan view, and FIG. 7B is a cross-sectional view. It is. 8A and 8B each show one process performed in an example of the manufacturing method of the ESD protection device 100, FIG. 8A is a plan view, and FIG. 8B is a cross-sectional view. It is. 9A and 9B each show one process performed in an example of the manufacturing method of the ESD protection device 100, FIG. 9A is a plan view, and FIG. 9B is a cross-sectional view. It is. 10A and 10B each show one process performed in an example of the manufacturing method of the ESD protection device 100, FIG. 10A is a plan view, and FIG. 10B is a cross-sectional view. It is. 11A and 11B each show one process performed in an example of the manufacturing method of the ESD protection device 100, FIG. 11A is a plan view, and FIG. 11B is a cross-sectional view. It is. 12A and 12B each show one process performed in an example of a method for manufacturing the ESD protection device 100, FIG. 12A is a plan view, and FIG. 12B is a cross-sectional view. It is. FIGS. 13A and 13B each show one process performed in an example of the manufacturing method of the ESD protection device 100, FIG. 13A is a plan view, and FIG. 13B is a cross-sectional view. It is. 14A and 14B each show one process performed in an example of the method for manufacturing the ESD protection device 100, FIG. 14A is a plan view, and FIG. 14B is a cross-sectional view. It is. FIGS. 15A and 15B each show one process performed in an example of the manufacturing method of the ESD protection device 100, FIG. 15A is a plan view, and FIG. 15B is a cross-sectional view. It is. FIGS. 16A and 16B are cross-sectional views of the ESD protection device 200 according to the second embodiment, respectively. FIG. 17 is a plan view showing one process performed in an example of the manufacturing method of the ESD protection device 200. 18A and 18B are cross-sectional views of the ESD protection device 300 according to the third embodiment, respectively. FIG. 19 is a plan view showing one process performed in an example of a method for manufacturing the ESD protection device 300. 20A and 20B are cross-sectional views of the ESD protection device 400 according to the fourth embodiment, respectively. FIG. 21 is a plan view showing one process performed in an example of the method for manufacturing the ESD protection device 400. FIG. 22A and 22B are cross-sectional views of the ESD protection device 500 according to the fifth embodiment, respectively. FIG. 23 is a cross-sectional view of the ESD protection device 1000 disclosed in Patent Document 1. As shown in FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Each embodiment shows an embodiment of the present invention exemplarily, and the present invention is not limited to the content of the embodiment. Moreover, it is also possible to implement combining the content described in different embodiment, and the implementation content in that case is also included in this invention. Further, the drawings are for helping understanding of the embodiment, and may not be drawn strictly. For example, a drawn component or a dimensional ratio between the components may not match the dimensional ratio described in the specification. In addition, the constituent elements described in the specification may be omitted in the drawings or may be drawn with the number omitted.

[First Embodiment]
1A, 1B, and 2 show an ESD protection device 100 according to the first embodiment. 1A and 1B are cross-sectional views of the ESD protection device 100, respectively. FIG. 1A illustrates a dashed-dotted line YY portion in FIG. FIG. 1B illustrates a dashed-dotted line XX portion in FIG. FIG. 2 is also a cross-sectional view of the ESD protection device 100, which is an enlarged view of FIG. 1B and 2 show a cross section perpendicular to the direction in which the first discharge electrode 7 and the second discharge electrode 8 to be described later extend, and the inner bottom surface 3 and the inner surface of the cavity 2 to be described later. The top surface 4 appears at the same time.

  The ESD protection device 100 includes a rectangular parallelepiped ceramic substrate 1. The ceramic substrate 1 is made of ceramic containing a glass component.

  A cavity 2 is formed inside the ceramic substrate 1. The cavity 2 includes an inner wall including an inner bottom surface 3 and an inner top surface 4. Details of the cavity 2 will be described later.

  A seal layer 5 is formed on the inner wall of the cavity 2. The seal layer 5 is formed in order to prevent the glass component contained in the ceramic substrate 1 from entering the inside of the cavity 2.

  A discharge auxiliary electrode 6 is formed on the seal layer 5 formed on the inner bottom surface 3 of the cavity 2. The discharge auxiliary electrode 6 is a ceramic containing a conductive component, and is formed in order to promote discharge between the first discharge electrode 7 and the second discharge electrode 8 described later.

  A first discharge electrode 7 and a second discharge electrode 8 are formed on the discharge auxiliary electrode 6 at an interval. In the ESD protection device 100, the first discharge electrode 7 and the second discharge electrode 8 are arranged in parallel.

  The first discharge electrode 7 has a strip shape, and includes a tip surface 7a, one side surface 7b, and the other side surface 7c. Similarly, the second discharge electrode 8 also has a strip shape, and includes a front end surface 8a, one side surface 8b, and the other side surface 8c.

  The one side surface 7 b of the first discharge electrode 7 and the one side surface 8 b of the second discharge electrode 8 are arranged to face each other, and the one side surface 7 b of the first discharge electrode 7 and the one side surface 8 b of the second discharge electrode 8 are arranged. A discharge gap G is formed.

  In the ESD protection device 100, the front end surface 7a, the one side surface 7b, and the other side surface 7c of the first discharge electrode 7 are at least partially exposed to the cavity portion 2, respectively. Similarly, the tip surface 8a, the one side surface 8b, and the other side surface 8c of the second discharge electrode 8 are at least partially exposed to the cavity portion 2, respectively.

  A first external electrode 9 is formed on one end of the ceramic substrate 1. The first external electrode 9 is electrically connected to the first discharge electrode 7. A second external electrode 10 is formed on the other end of the ceramic substrate 1. The second external electrode 10 is electrically connected to the second discharge electrode 8.

  With reference to FIG. 2 which expanded FIG. 1 (B), the detail of the cavity part 2 is further demonstrated.

  In the ESD protection device 100, a pair of bent portions 3 a and 3 b are formed on the inner bottom surface 3 of the cavity portion 2 so as to protrude to the inner side of the cavity portion 2, and are formed on the inner top surface 4 of the cavity portion 2. A pair of bent portions 4a and 4b projecting from the inside of the cavity 2 are formed. Then, between the bent portions 3a and 3b and between the bent portions 4a and 4b of the hollow portion 2, from outside the bent portions 3a and 3b and outside the bent portions 4a and 4b. In addition, a high-back space 2H having a large height from the inner bottom surface 3 to the inner top surface 4 is formed.

2, described bending portion 3a, 3b, 4a, at the portion 4b is formed, the height of the inner bottom surface 3 to the inner top surface 4 at t _A, in the high back space portion 2H, the largest inner bottom surface from 3 to the inner top surface 4 of the height indicated by t _B. Moreover, the range of the high-back space part 2H is shown by a chain line in FIG.

  Although the manufacturing method of the ESD protection device 100 will be described later, the cavity 2 is a cavity forming paste that disappears by firing between the ceramic green sheet and the ceramic green sheet for producing the ceramic substrate 1. By forming the cavity portion forming paste layer, the cavity portion forming paste is eliminated during firing. The high-back space 2H is formed in a portion where the cavity portion forming paste is applied in a plurality of times and the thickness of the cavity portion forming paste layer is increased.

  In FIG. 3, in the manufacturing process of the ESD protection device 100, a lower seal paste layer 15A is formed on the upper main surface of the ceramic green sheet 11, and a discharge auxiliary electrode paste layer (not shown) is formed on the lower seal paste layer 15A. The first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 are formed on the discharge auxiliary electrode paste layer, and the first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 are formed. A first cavity forming paste layer 12A is formed on the discharge auxiliary electrode paste layer, and a second cavity forming paste layer 12B is formed on the first cavity forming paste layer 12A. Shows the state. FIG. 3 is a plan view.

  The second cavity forming paste layer 12B is smaller than the first cavity forming paste layer 12A and extends in the same direction as the direction in which the first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 extend. (So as to be parallel).

  The size in the vertical direction and the horizontal direction of the first cavity portion forming paste layer 12A is approximately the size in the vertical direction and the horizontal direction of the cavity portion 2. In addition, a region in which the second cavity portion forming paste layer 12B is formed on the first cavity portion forming paste layer 12A substantially becomes a region in which the high-back space portion 2H of the cavity portion 2 is formed. .

  The description will be continued with reference to FIG. 2 again.

  The bent portions 3a and 3b formed on the inner bottom surface 3 of the cavity portion 2 and the bent portions 4a and 4b formed on the inner top surface 4 of the cavity portion 2 are formed by laminating a plurality of ceramic green sheets. When the pressure is integrated, the region where only the first cavity portion forming paste layer 12A is formed and the second cavity portion forming paste layer 12B are superimposed on the first cavity portion forming paste layer 12A. In other words, it is formed due to the difference in thickness of the cavity portion forming paste layer at the boundary portion with the region formed in this manner.

  Immediately above the bent portions 3a and 3b formed on the inner bottom surface 3 of the cavity portion 2, the discharge auxiliary electrode 6 is bent, and further, the first discharge electrode 7 and the second discharge electrode 8 are bent respectively. . As a result, each of the first discharge electrode 7 and the second discharge electrode 8 falls to the inner bottom surface 3 side in the high-back space 2H of the cavity 2.

  The ESD protection device 100 having the above structure includes the cavity portion 2 between the bent portions 3a and 3b and between the bent portions 4a and 4b, and outside the bent portions 3a and 3b, and Since the high-back space portion 2H is formed in which the height from the inner bottom surface 3 to the inner top surface 4 is larger than the outside of the bent portions 4a and 4b, the volume of the cavity portion 2 is large. Therefore, in the ESD protection device 100, the rise in temperature inside the cavity 2 due to discharge is mitigated, and IR deterioration due to repeated discharge is suppressed.

  Further, in the ESD protection device 100, since the cavity 2 is sufficiently large in the vertical direction and the horizontal direction, respectively, the tip surface 7a, the one side surface 7b, and the other side surface 7c of the first discharge electrode 7 are Moreover, the front end surface 8a, the one side surface 8b, and the other side surface 8c of the second discharge electrode 8 are at least partially exposed to the cavity portion 2, respectively. The fact that the cavity 2 is large in the vertical and horizontal directions also contributes to increasing the volume of the cavity 2 and contributes to suppressing IR deterioration due to repeated discharge.

  Further, in the ESD protection device 100, the first discharge electrode 7 and the second discharge electrode 8 are bent just above the bent portions 3a and 3b formed on the inner bottom surface 3 of the cavity portion 2, respectively. And the 1st discharge electrode 7 and the 2nd discharge electrode 8 are falling in the inner bottom face 3 side in the high-back space part 2H of the cavity part 2, respectively. As a result, in the ESD protection device 100, a large space is provided above the discharge gap G that generates high heat during discharge, and the rise in temperature inside the cavity 102 due to discharge is mitigated. IR deterioration due to discharge is suppressed.

  In order to confirm the effectiveness of the present invention, the following experiment was conducted. First, as an example, 250 ESD protection devices 100 according to the first embodiment were manufactured. As a comparative example, 250 ESD protection devices 1100 having a conventional structure shown in FIG. 4 were manufactured.

  The ESD protection device 1100 of the comparative example includes a ceramic substrate 201. A cavity 202 is formed inside the ceramic substrate 201. A seal layer 205 is formed on the inner wall of the cavity 202. A discharge auxiliary electrode 206 is formed on the seal layer 205. A first discharge electrode 207 and a second discharge electrode 208 are formed on the discharge auxiliary electrode 206.

  The ESD protection device 1100 of the comparative example is different from the ESD protection device 100 of the example in the following points. The cavity portion 202 of the ESD protection device 1100 does not include a high-back space portion, and the height from the inner bottom surface to the inner top surface is substantially uniform. As a result, the cavity 202 of the ESD protection device 1100 is not formed with a bent portion, and the discharge auxiliary electrode 206, the first discharge electrode 207, and the second discharge electrode 208 are not bent. Since the cavity 202 of the ESD protection device 1100 does not include a high-back space, the volume of the cavity 202 is small. Other configurations of the ESD protection device 1100 are the same as those of the ESD protection device 100.

  First, the operability of each of the ESD protection device 100 and the ESD protection device 1100 was confirmed. Specifically, the determination was made from the operation rate at the time of applying arbitrary ESD (electro-static discharge). More specifically, according to IEC (International Electrotechnical Commission) standard (IEC61000-4-2), ESD of a predetermined voltage is applied to each of 100 samples by contact discharge. The operation rate was examined every time. There are four types of ESD voltages: 2 kV, 3 kV, 4 kV, and 5 kV. In this test, the operating rate was examined by sequentially increasing the voltage for the same sample.

The case where the operation rate was less than 10% was evaluated as x. The case where the operation rate was 10% or more and less than 50% was evaluated as Δ. The case where the operation rate was 50% or more and less than 80% was rated as “◯”. The case where the operating rate was 80% or more was marked with ◎. The results are shown in Table 1.

  As can be seen from Table 1, the operability of the ESD protection device 100 and the operability of the ESD protection device 1100 were equivalent and both were good.

Next, each of the ESD protection device 100 and the ESD protection device 1100 was examined for resistance to IR deterioration caused by repeated discharge. Specifically, it was judged from the yield rate after repeatedly applying any ESD. More specifically, according to the IEC standard (IEC61000-4-2), ESD of a predetermined voltage is continuously applied 100 times to each of 50 samples (50 at each voltage) by IR. Was reduced to less than 10 ⁴ Ω to be defective, and the yield rate was examined for each applied voltage. There are three types of ESD voltages: 8 kV, 15 kV, and 30 kV. In this test, different samples were used for each voltage.

The case where the yield rate was less than 10% was evaluated as x. A case where the yield rate was 10% or more and less than 50% was evaluated as Δ. The case where the non-defective product rate was 50% or more and less than 80% was evaluated as ◯. A case where the yield rate was 80% or more was marked as ◎. The results are shown in Table 2.

  As can be seen from Table 2, the ESD protection device 100 has better IR degradation resistance than the ESD protection device 1100, and the IR did not decrease even when high voltage such as 15 kV or 30 kV was repeatedly applied. Since the ESD protection device 100 according to the example includes the cavity portion 2 having a large volume compared to the ESD protection device 1100 according to the comparative example, the inside of the cavity portion 2 becomes extremely high even if the discharge is repeated. It is considered that the deterioration of IR was suppressed. On the other hand, in the ESD protection device 1100 according to the comparative example, IR deteriorated by repeated application of 15 kV, and IR significantly deteriorated by repeated application of 30 kV.

  The ESD protection device 100 according to the first embodiment can be manufactured, for example, by the method shown in FIGS. 5 (A), (B) to FIGS. 14 (A), (B). However, each figure (A) is a top view which shows one process implemented in the said manufacturing method. Each drawing (B) is a cross-sectional view thereof, and shows a dot-dash line XX portion of the drawing (A).

  First, a ceramic green sheet, a discharge auxiliary electrode paste, a seal paste, a discharge electrode paste, a cavity forming paste, and an external electrode paste were prepared. The order of production is arbitrary.

(1) Production of ceramic green sheet First, a ceramic material was prepared. In the present embodiment, a material having a composition centered on Ba, Al, and Si is used as the ceramic material. Each raw material was prepared and mixed so as to have a predetermined composition, and calcined at 800-1000 ° 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. Further, a binder and a plasticizer were added and mixed to obtain a slurry. The slurry thus obtained was molded by the doctor blade method to obtain a ceramic green sheet having a thickness of 50 μm.

Note that the ceramic material is not particularly limited to the above materials, but is Al ₂ O ₃ , cordierite, mullite, foresterite, LTCC material obtained by adding glass or the like to CaZrO ₃ , Al ₂ O ₃ , cordier. HTCC materials such as erlite, mullite, and forestlight, ferrite materials, dielectric materials, resin materials, and the like may be used.

(2) Preparation of discharge electrode paste 40% by weight of Cu powder having an average particle diameter of 1 μm, 40% by weight of Cu powder having an average particle diameter of 3 μm, and 20% by weight of an organic vehicle prepared by dissolving ethyl cellulose in terpineol. Was prepared and mixed with three rolls to obtain a discharge electrode paste.

  The material of the discharge electrode is not limited to Cu, and may be Ag, Pd, Pt, Al, Ni, W, or a combination thereof. However, it is preferable to use Cu or Ag having high thermal conductivity.

(3) Preparation of discharge auxiliary electrode paste Ceramic composed of Cu / Al ₂ O ₃ core / shell powder having an average particle diameter of about 2 μm and a composition centered on Ba, Al, and Si having an average particle diameter of 0.5 μm Powder was prepared at a ratio of 80:20 vol%, a binder resin and a solvent were added, and the mixture was stirred and mixed with three rolls to obtain a discharge auxiliary electrode paste. In the discharge auxiliary electrode paste, the binder resin composed of ethyl cellulose or the like and the solvent were 20 wt%, and the remaining 80 wt% was core / shell powder and ceramic powder.

  The discharge auxiliary electrode is not limited to a combination of a conductor and insulator particles as in the present embodiment, and beads such as conductors, semiconductors, insulator particles, and acrylic resin beads are appropriately used. , Selected and combined.

(4) Production of cavity portion forming paste By blending 38 wt% of crosslinked acrylic resin beads having an average particle diameter of 1 μm and 62 wt% of organic vehicle in which 10 wt% of etose resin is dissolved in terpineol, and mixing them by three rolls Then, a cavity forming paste was prepared.

  The material for the cavity portion forming paste may be any material that disappears upon firing, and is not limited to a resin-based material. Therefore, for example, carbon may be used.

(5) Preparation of seal paste Al ₂ O ₃ powder was prepared as an inorganic oxide, a binder resin and a solvent were added, and the mixture was stirred and mixed with three rolls to obtain a seal paste. The seal paste was 44 wt% of a binder resin made of ethyl cellulose or the like and a solvent, and the remaining 56 wt% was Al ₂ O ₃ powder.

The inorganic oxide of the seal layer is not limited to Al ₂ O ₃ and may be other inorganic oxides such as BaO, CaO, TiO ₂ , ZrO ₂ , SrO, Nb ₂ O ₅ .

(6) Preparation of external electrode paste 80 wt% of Cu powder having an average particle diameter of about 1 μm, 5 wt% of alkali borosilicate glass frit having an average particle diameter of about 1 μm at a transition point of 620 ° C. and a softening point of 720 ° C. An organic vehicle prepared by dissolving ethyl cellulose in terpineol was mixed with 15 wt%, and mixed with three rolls to prepare an external electrode paste.

  The material of the external electrode is not limited to Cu, and may be other metals such as Ag, Pd, Pt, Al, Ni, and W. Also, a combination of Cu and Ni may be used.

(7) Application of Various Pastes to Ceramic Green Sheet As shown in FIGS. 5A and 5B, one ceramic green sheet 11 was prepared. The dimensions of the ceramic green sheet 11 were 1.0 mm in length, 0.5 mm in width, and 50 μm in thickness. The ceramic green sheet 11 is usually prepared as a mother ceramic green sheet in which a large number of ceramic green sheets 11 are arranged in a matrix in order to manufacture a large number of ESD protection devices at once. For convenience, one ceramic green sheet 11 is shown in FIGS.

  Next, as shown in FIGS. 6A and 6B, a seal paste was applied in a predetermined shape on the upper main surface of the ceramic green sheet 11 to form a lower seal paste layer 15A.

  Next, as shown in FIGS. 7A and 7B, a discharge auxiliary electrode paste is applied on the lower seal paste layer 15A to a size smaller than that of the lower seal paste layer 15A, and discharge assist is performed. An electrode paste layer 16 was formed.

  Next, as shown in FIGS. 8A and 8B, a conductive paste is applied over the discharge auxiliary electrode paste layer 16 over the upper main surface of the ceramic green sheet 11, and each has a predetermined shape. A first discharge electrode paste layer 17 and a second discharge electrode paste layer 18 were formed.

  Next, as shown in FIGS. 9A and 9B, firing is performed on the discharge auxiliary electrode paste layer 16 on which the first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 are formed. The disappearing cavity forming paste was applied to form a first cavity forming paste layer 12A.

  Next, as shown in FIGS. 10A and 10B, the first cavity portion forming paste layer 12 </ b> A disappears by firing to a size smaller than the first cavity portion forming paste layer 12 </ b> A. A cavity forming paste was applied to form a second cavity forming paste layer 12B.

  Next, as shown in FIGS. 11A and 11B, a seal paste is applied on the first cavity portion forming paste layer 12A and the second cavity portion forming paste layer 12B, and an upper seal paste is applied. In the state where the layer 15B is formed and the first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 are partially led to the outside, respectively, the lower seal paste layer 15A and the upper seal paste layer 15B, Surrounding the discharge auxiliary electrode paste layer 16, the first discharge electrode paste layer 17, the second discharge electrode paste layer 18, the first cavity forming paste layer 12A, and the second cavity forming paste layer 12B .

(8) Lamination of Ceramic Green Sheet Next, as shown in FIGS. 12A and 12B, a lower seal paste layer 15A, a discharge auxiliary electrode paste layer 16, a first discharge electrode paste layer 17, Ceramic green sheet 11 formed with second discharge electrode paste layer 18, first cavity forming paste layer 12A, second cavity forming paste layer 12B, and upper seal paste layer 15B, and other A ceramic green sheet 11 was laminated. The other ceramic green sheets 11 were also prepared and laminated as mother ceramic green sheets in which a large number of ceramic green sheets 11 were arranged in a matrix.

(9) Production of unsintered ceramic green sheet laminate Next, as shown in FIGS. 13A and 13B, a plurality of laminated ceramic green sheets 11 are pressed and integrated to form an unsintered ceramic. Green sheet laminated body 1 'was produced. At this time, the lower sealing paste layer 15A and the upper sealing paste layer 15B were integrated, and the first cavity forming paste layer 12A and the second cavity forming paste layer 12B were integrated.

  Up to this point, a large number of unfired ceramic green sheet laminates 1 ′ have been produced at once using a mother ceramic green sheet in which a large number of ceramic green sheets 11 are arranged in a matrix. Used and cut into individual unfired ceramic green sheet laminates 1 '. The dimensions of the unfired ceramic green sheet laminate 1 ′ after cutting were 1.0 mm in length, 0.5 mm in width, and 0.3 mm in thickness.

(10) Firing Next, as shown in FIGS. 14A and 14B, the unfired ceramic green sheet laminate 1 ′ is placed in a predetermined atmosphere (for example, in an N ₂ atmosphere) and has a predetermined temperature profile. And the first cavity portion forming paste layer 12A and the second cavity portion forming paste layer 12B disappeared to obtain a ceramic substrate 1 having the cavity portion 2 formed therein. In the ceramic substrate 1, the seal layer 5 is formed on the inner wall of the cavity 2, the discharge auxiliary electrode 6 is formed on the seal layer 5, and the first discharge electrode 7 is spaced over the discharge auxiliary electrode 6. And the second discharge electrode 8 are formed. The cavity 2 is also formed with a high-back space 2H.

(11) Formation of External Electrode Finally, as shown in FIGS. 15A and 15B, the first external electrode 9 and the second external electrode 10 were formed on both ends of the ceramic substrate 1. Specifically, first, an external electrode paste was applied to both ends of the ceramic substrate 1 and baked. Subsequently, a plating layer (for example, the first layer is Ni and the second layer is Sn) is applied to the surface by electrolytic plating to form the first external electrode 9 and the second external electrode 10.

  Thus, the ESD protection device 100 according to the first embodiment is completed.

[Second Embodiment]
FIGS. 16A and 16B show an ESD protection device 200 according to the second embodiment. 16A and 16B are cross-sectional views of the ESD protection device 200, respectively. FIG. 16A illustrates a dashed-dotted line YY portion in FIG. FIG. 16B illustrates a dashed-dotted line XX portion in FIG.

  The ESD protection device 200 is obtained by partially changing the ESD protection device 100 according to the first embodiment. Specifically, in the ESD protection device 100, the direction in which the high-profile space 2H extends is parallel to the direction in which the first discharge electrode 7 and the second discharge electrode 8 extend. The direction in which the space 22H extends was perpendicular to the direction in which the first discharge electrode 7 and the second discharge electrode 8 extend. Other configurations of the ESD protection device 200 are the same as those of the ESD protection device 100.

  In FIG. 17, in the manufacturing process of the ESD protection device 200, a lower seal paste layer 15A is formed on the upper main surface of the ceramic green sheet 11, and a discharge auxiliary electrode paste layer (not shown) is formed on the lower seal paste layer 15A. The first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 are formed on the discharge auxiliary electrode paste layer, and the first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 are formed. A first cavity forming paste layer 12C is formed on the discharge auxiliary electrode paste layer, and a second cavity forming paste layer 12D is formed on the first cavity forming paste layer 12C. Shows the state.

  As can be seen from FIG. 17, in the ESD protection device 200, the second cavity forming paste layer 12D is formed so as to extend perpendicularly to the direction in which the first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 extend. Forming. As a result, in the ESD protection device 200, the direction in which the high-back space 22H extends is perpendicular to the direction in which the first discharge electrode 7 and the second discharge electrode 8 extend.

  As shown in FIG. 16B, also in the ESD protection device 200, the bent portions 23 a and 23 b are formed on the inner bottom surface 23 of the cavity portion 22, and the bent portion 24 a is formed on the inner top surface 24 of the cavity portion 22. , 24b are formed. And between the bent parts 23a and 23b and between the bent parts 24a and 24b of the hollow part 22, from the outside of the bent parts 23a and 23b and the outside of the bent parts 24a and 24b. In addition, a high-back space 22H having a large height from the inner bottom surface 23 to the inner top surface 24 is formed.

  The ESD protection device 200 has a high volume space 22H because the height from the inner bottom surface 23 to the inner top surface 24 is large, and the volume of the cavity portion 22 is large. Therefore, in the ESD protection device 200, the rise in temperature inside the cavity 22 due to discharge is mitigated, and IR deterioration due to repeated discharge is suppressed.

[Third Embodiment]
18A and 18B show an ESD protection device 300 according to the third embodiment. However, FIGS. 18A and 18B are cross-sectional views of the ESD protection device 300, respectively. FIG. 18A illustrates a dashed-dotted line YY portion in FIG. FIG. 18B illustrates a dashed-dotted line XX portion in FIG.

  The ESD protection device 300 is also partially changed from the ESD protection device 100 according to the first embodiment. Specifically, in the ESD protection device 100, the one side surface 7b of the first discharge electrode 7 and the one side surface 8b of the second discharge electrode 8 are arranged to face each other, and the one side surface 7b of the first discharge electrode 7 and the second side surface 7b are arranged. Although the discharge gap G is formed with the one side surface 8b of the discharge electrode 8, in the ESD protection device 300, the front end surface 7a of the first discharge electrode 7 and the front end surface 8a of the second discharge electrode 8 are arranged to face each other. The discharge gap G was formed by the tip surface 7 a of the first discharge electrode 7 and the tip surface 8 a of the second discharge electrode 8. Other configurations of the ESD protection device 300 are the same as those of the ESD protection device 100.

  In FIG. 19, in the manufacturing process of the ESD protection device 300, the lower seal paste layer 15A is formed on the upper main surface of the ceramic green sheet 11, and the discharge auxiliary electrode paste layer (not shown) is formed on the lower seal paste layer 15A. The first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 are formed on the discharge auxiliary electrode paste layer, and the first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 are formed. A first cavity portion forming paste layer 12E is formed on the discharge auxiliary electrode paste layer, and a second cavity portion forming paste layer 12F is formed on the first cavity portion forming paste layer 12E. Shows the state.

  As shown in FIG. 18B, also in the ESD protection device 300, bent portions 33 a and 33 b are formed on the inner bottom surface 33 of the cavity portion 32, and the bent portion 34 a is formed on the inner top surface 34 of the cavity portion 32. , 34b are formed. Then, between the bent portions 33a and 33b and between the bent portions 34a and 34b of the hollow portion 32, from the outside of the bent portions 33a and 33b and the outside of the bent portions 34a and 34b. In addition, a high-back space 32H having a large height from the inner bottom surface 33 to the inner top surface 34 is formed.

  The ESD protection device 300 has a large volume from the inner bottom surface 33 to the inner top surface 34 and has a high volume space 32H. Therefore, in the ESD protection device 300, the rise in temperature inside the cavity 32 due to discharge is mitigated, and IR deterioration due to repeated discharge is suppressed.

[Fourth Embodiment]
20A and 20B show an ESD protection device 400 according to the fourth embodiment. 20A and 20B are cross-sectional views of the ESD protection device 400, respectively. FIG. 20A illustrates a dashed-dotted line YY portion in FIG. FIG. 20B illustrates a dashed-dotted line XX portion in FIG.

  The ESD protection device 400 is a partial modification of the ESD protection device 300 according to the third embodiment. Specifically, in the ESD protection device 300, the direction in which the high-back space 32H extends is parallel to the direction in which the first discharge electrode 7 and the second discharge electrode 8 extend. The direction in which the space portion 42H extends was perpendicular to the direction in which the first discharge electrode 7 and the second discharge electrode 8 extend. Other configurations of the ESD protection device 400 are the same as those of the ESD protection device 300.

  In FIG. 21, in the manufacturing process of the ESD protection device 400, the lower seal paste layer 15A is formed on the upper main surface of the ceramic green sheet 11, and the discharge auxiliary electrode paste layer (not shown) is formed on the lower seal paste layer 15A. The first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 are formed on the discharge auxiliary electrode paste layer, and the first discharge electrode paste layer 17 and the second discharge electrode paste layer 18 are formed. A first cavity forming paste layer 12G is formed on the discharge auxiliary electrode paste layer, and a second cavity forming paste layer 12H is formed on the first cavity forming paste layer 12G. Shows the state.

  20B, also in the ESD protection device 400, the bent portions 43a and 43b are formed on the inner bottom surface 43 of the cavity portion 42, and the bent portion 44a is formed on the inner top surface 44 of the cavity portion 42. , 44b are formed. Then, between the bent portions 43a and 43b and between the bent portions 44a and 44b of the hollow portion 42, from the outside of the bent portions 43a and 43b and the outside of the bent portions 44a and 44b. In addition, a high-back space portion 42H having a large height from the inner bottom surface 43 to the inner top surface 44 is formed.

  The ESD protection device 400 has a high volume space 42H because the height from the inner bottom surface 43 to the inner top surface 44 is large and the high-back space portion 42H is formed. Therefore, in the ESD protection device 400, the rise in temperature inside the cavity 42 due to discharge is mitigated, and IR deterioration due to repeated discharge is suppressed.

[Fifth Embodiment]
22 (A) and 22 (B) show an ESD protection device 500 according to the fifth embodiment. However, FIGS. 22A and 22B are cross-sectional views of the ESD protection device 500, respectively. FIG. 22A illustrates a dashed-dotted line YY portion in FIG. FIG. 22B illustrates a dashed-dotted line XX portion in FIG.

  The ESD protection device 500 is a partial modification of the ESD protection device 400 according to the fourth embodiment. Specifically, in the ESD protection device 400, the tip surface of the first discharge electrode 7 is configured by one tip surface 7a, and the tip surface of the second discharge electrode 8 is configured by one tip surface 8a. In the ESD protection device 500, the front end surface of the first discharge electrode 57 is composed of two front end surfaces 57aa and 57ab, and the front end surface of the second discharge electrode 58 is composed of two front end surfaces 58a and 58b. In the ESD protection device 500, the tip surfaces 57aa and 57ab of the first discharge electrode 57 and the tip surfaces 58aa and 58ab of the second discharge electrode 58 are pointed. Other configurations of the ESD protection device 500 are the same as those of the ESD protection device 400.

  In the ESD protection device 500, since the tip surfaces 57aa and 57ab of the first discharge electrode 57 and the tip surfaces 58aa and 58ab of the second discharge electrode 58 are pointed, the electric field concentrates and it becomes easier to discharge. ing.

  The ESD protection devices 100, 200, 300, 400, and 500 according to the first to fifth embodiments have been described above. However, the present invention is not limited to the contents described above, and various modifications can be made in accordance with the spirit of the invention.

  For example, in the ESD protection devices 100 and 300, the high-back space portions 2H, 32H, and 62H are formed to extend in parallel to the direction in which the first discharge electrode 7 and the second discharge electrode 8 extend. Also. Further, in the ESD protection devices 200, 400, 500, the high-back space portions 22H, 42H are formed so as to extend perpendicularly to the direction in which the first discharge electrodes 7, 57 and the second discharge electrodes 8, 58 extend. . However, the shape of the high-back space is arbitrary and is not limited to the above content. That is, in manufacturing the ESD protection device of the present invention, the second cavity forming paste layer formed on the first cavity forming paste layer has a size as viewed in the plane direction for forming the first cavity. It may be smaller than the paste layer and may have any shape. For example, the lengths of the second cavity portion forming paste layers 12B, 12D, 12F, and 12H are shorter than those illustrated, and the lengths of the high-back space portions 2H, 22H, 32H, 42H, and 62H are Each may be shortened.

  Further, in manufacturing the ESD protection device 100, 200, 300, 400, 500, on the first cavity forming paste layers 12A, 12C, 12E, 12G, the second cavity forming paste layers 12B, 12D, Although 12F and 12H are formed, the paste layer for forming the third cavity may be formed without being limited to this. Further, if necessary, a cavity forming paste layer after the fourth cavity forming paste layer may be formed.

DESCRIPTION OF SYMBOLS 1 ... Ceramic base material 1 '... Unbaked ceramic green sheet laminated body 2, 22, 32, 42, 62 ... Cavity part 2H, 22H, 32H, 42H, 62H ... High back space part 3 , 23, 33, 43, 63 ... inner bottom surface 4, 24, 34, 44, 64 ... inner top surfaces 3a, 3b, 4a, 4b, 23a, 23b, 24a, 24b, 33a, 33b, 34a, 34b, 43a, 43b, 44a, 44b, 64a, 64b ... bent portion 5 ... seal layer 6 ... discharge auxiliary electrode 7, 57 ... first discharge electrode 7a, 57aa, 57ab ... Front end surface 7b ... One side surface 7c ... Other side surface 8, 58 ... Second discharge electrodes 8a, 58aa, 58ab ... Front end surface 8b ... One side surface 8c ... Other side surface 9 ... 1st external electrode 10 ... 2nd external electrode 11 ... Ceramic green sheets 12A, 12C, 12E, 12G ... first cavity forming paste layers 12B, 12D, 12F, 12H ... second cavity forming paste layer 15A ... lower seal paste layer 15B .. Upper seal paste layer 16 ... discharge auxiliary electrode paste layer 17 ... first discharge electrode paste layer 18 ... second discharge electrode paste layer 100, 200, 300, 400, 500 ... ESD protection device G ... Gap

Claims (11)

A ceramic substrate in which a cavity having an inner wall including at least an inner bottom surface and an inner top surface is formed;
A sealing layer formed on the inner wall of the cavity,
A discharge auxiliary electrode formed on the seal layer formed on the inner bottom surface of the cavity,
An ESD protection device comprising a first discharge electrode and a second discharge electrode formed on the auxiliary discharge electrode at an interval,
When one of the cross-sections in which the inner bottom surface and the inner top surface of the cavity portion appear at the same time, 1 protrudes to the inner side of the cavity portion on at least one of the inner bottom surface and the inner top surface. A pair of bent portions are formed, and the height of the hollow portion from the inner bottom surface to the inner top surface is greater between the pair of bent portions than the outside of the pair of bent portions. An ESD protection device with a large, high-back space. Each of the first discharge electrode and the second discharge electrode has a strip shape having a lower main surface, an upper main surface, a tip surface, one side surface, and the other side surface,
The one side surface of the first discharge electrode and the one side surface of the second discharge electrode are arranged in parallel and facing each other,
The ESD protection device according to claim 1, wherein a discharge gap is formed between the one side surface of the first discharge electrode and the one side surface of the second discharge electrode, which are arranged to face each other. Each of the first discharge electrode and the second discharge electrode has a strip shape having a lower main surface, an upper main surface, a tip surface, one side surface, and the other side surface,
The front end surface of the first discharge electrode and the front end surface of the second discharge electrode are arranged to face each other,
2. The ESD protection device according to claim 1, wherein a discharge gap is formed between the front end surface of the first discharge electrode and the front end surface of the second discharge electrode that are arranged to face each other.   The front end surface, the one side surface, and the other side surface of each of the first discharge electrode and the second discharge electrode are at least partially exposed to the cavity. Or the ESD protection device described in 3. The pair of bent portions are formed on the inner bottom surface of the hollow portion,
Each of the first discharge electrode and the second discharge electrode is bent just above the bent portion formed on the inner bottom surface,
5. The ESD protection device according to claim 1, wherein each of the first discharge electrode and the second discharge electrode falls into the inner bottom surface side in the high-back space portion.   The ESD protection device according to any one of claims 1 to 5, wherein a direction in which the first discharge electrode and the second discharge electrode extend and a direction in which the high space portion extends are parallel to each other.   The ESD protection device according to any one of claims 1 to 5, wherein a direction in which the first discharge electrode and the second discharge electrode extend and a direction in which the high-back space portion extends are perpendicular to each other. Preparing a plurality of ceramic green sheets;
Applying a seal paste in a predetermined shape to the upper main surface of one ceramic green sheet to form a lower seal paste layer;
A step of applying a discharge auxiliary electrode paste on the lower seal paste layer to a size smaller than the lower seal paste layer to form a discharge auxiliary electrode paste layer;
A conductive paste is applied over the discharge auxiliary electrode paste layer over the upper main surface of the ceramic green sheet to form a first discharge electrode paste layer and a second discharge electrode paste layer each having a predetermined shape. Process,
A cavity forming paste that disappears by firing is applied on the discharge auxiliary electrode paste layer on which the first discharge electrode paste layer and the second discharge electrode paste layer are formed, and the first cavity forming paste is formed. Forming a paste layer;
On the first cavity portion forming paste layer, a cavity portion forming paste that disappears by firing is applied to a size smaller than the first cavity portion forming paste layer, and the second cavity portion forming paste layer is applied. Forming a step;
The seal paste is applied on the first cavity forming paste layer and the second cavity forming paste layer to form an upper seal paste layer, and the first discharge electrode paste layer and the second With the discharge electrode paste layer partially led to the outside, the lower seal paste layer and the upper seal paste layer, the discharge auxiliary electrode paste layer, the first discharge electrode paste layer, Surrounding the second discharge electrode paste layer, the first cavity forming paste layer, and the second cavity forming paste layer;
The lower seal paste layer, the discharge auxiliary electrode paste layer, the first discharge electrode paste layer, the second discharge electrode paste layer, the first cavity forming paste layer, and the second cavity The ceramic green sheet on which the forming paste layer and the upper seal paste layer are formed and the other ceramic green sheet are laminated, pressed and integrated to form an unfired ceramic green sheet laminate. A manufacturing process;
Firing the unfired ceramic green sheet laminate, eliminating the first cavity forming paste layer and the second cavity forming paste layer, and a ceramic substrate having a cavity formed therein; A seal layer formed on the inner wall of the cavity, a discharge auxiliary electrode formed on the seal layer, and a first discharge electrode and a second discharge electrode formed on the discharge auxiliary electrode with a space therebetween And a method of manufacturing an ESD protection device.   The ESD protection device according to claim 8, wherein a direction in which the first discharge electrode paste layer and the second discharge electrode paste layer extend and a direction in which the second cavity forming paste layer extends are parallel to each other. Production method.   The ESD protection device according to claim 8, wherein a direction in which the first discharge electrode paste layer and the second discharge electrode paste layer extend and a direction in which the second cavity forming paste layer extends are perpendicular to each other. Production method. Comprising a step of forming a third cavity forming paste layer,
The manufacturing method of the ESD protection device according to any one of claims 8 to 10, further comprising a step of forming a cavity forming paste layer after the fourth cavity forming paste layer as necessary. Method.

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