TWI506900B - Electrostatic discharge protection device - Google Patents

Description

Electrostatic discharge protection device

The present invention relates to an ESD protection device for protecting a semiconductor device or the like from electrostatic damage.

In recent years, when a home appliance is used, the number of times of plugging and unplugging a cable as an input/output interface tends to increase, so that static electricity is easily applied to the input/output connection portion. In addition, it is difficult to make a via with the miniaturization of design rules due to the high frequency of the signal frequency, and the LSI itself is also vulnerable to static electricity.

Therefore, an ESD protection device is widely used to protect semiconductor devices such as LSI from electrostatic discharge (ESD) (Electron-Statics Dissharge).

As such an ESD protection device, an ESD protection device (surge absorption element) has been proposed (see Patent Document 1), which is provided inside a ceramic base material (insulating ceramic layer) having a pair of external electrodes, and is provided with an external electrode. The internal electrode and the discharge space are turned on, and the discharge gas is limited to the discharge space.

However, in the ESD protection device of Patent Document 1, when a magnetic material such as ferrite is used as the ceramic base material, there is a problem in that the magnetic material is electrically conductive due to discharge, and a short-circuit defect occurs.

Further, as another ESD protection device, an ESD protection device (see Patent Document 2) has been proposed, which includes a ceramic multilayer substrate, and at least one pair of discharge electrodes formed at a predetermined interval and opposed to each other a ceramic multilayer substrate; and an external electrode formed on the surface of the ceramic multilayer substrate and connected to the discharge electrode, wherein the region between the pair of discharge electrodes is provided with a conductive material coated with an inorganic material having no conductivity Dispersed auxiliary electrode.

However, even if the ESD protection device includes the auxiliary electrode as described above, when a magnetic material such as ferrite is used as the base material of the ceramic multilayer substrate, there is a problem that the magnetic material is conductorized by the discharge, resulting in a short circuit failure.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2001-43954

[Patent Document 2] Japanese Patent No. 4434314

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an ESD protection device which is excellent in repeatability and which does not deteriorate in characteristics when ESD is repeatedly applied while suppressing short-circuit failure.

In order to solve the above problems, an ESD protection device according to the present invention includes: a magnetic substrate; and a counter electrode that is formed on the surface or inside of the magnetic substrate and that is formed by being spaced apart from each other at a front end portion a side opposite electrode and another opposite electrode, wherein the one side opposite electrode and the other side opposite electrode form a discharge gap portion that generates a discharge when ESD is applied; and a protective insulating layer. The surface of the magnetic substrate is disposed at least in a region facing the discharge gap portion to prevent deterioration of insulation properties of the magnetic substrate due to discharge.

Further, in the ESD protection device of the present invention, the protective insulating layer is preferably disposed between the front end portion of the one facing electrode and the front end portion of the other opposing electrode and the magnetic substrate.

Further, another ESD protection device according to the present invention includes: a magnetic base material; and a counter electrode that is formed on the surface or inside of the magnetic base material, and includes one side that is spaced apart from each other at a front end portion and faces each other a counter electrode and a counter electrode on the other side, wherein the one side opposite electrode and the other side opposite electrode form a discharge gap portion that generates a discharge when ESD is applied; and the discharge auxiliary electrode is connected separately And constituting the opposite electrode and the other opposite electrode of the counter electrode, and the opposite electrode is disposed from the opposite electrode and the opposite electrode; and a protective insulating layer It is disposed between the discharge auxiliary electrode and the magnetic substrate to prevent deterioration of insulation properties of the magnetic substrate due to discharge.

Further, it is preferable that the protective insulating layer is disposed beyond a region in which the discharge auxiliary electrode is formed and disposed in a region around the protective insulating layer.

Further, the protective insulating layer preferably contains a crystalline inorganic oxide.

The protective insulating layer preferably contains a glass component.

Further, the magnetic substrate preferably contains a glass component.

Further, a cavity portion may be provided inside the magnetic base material, and the discharge gap portion may face the cavity portion.

Further, the protective insulating layer is preferably disposed in a region of the magnetic substrate exposed by the cavity portion.

In the ESD protection device of the present invention, the protective substrate is provided on the surface or inside of the magnetic substrate facing the region between the end portion of the counter electrode facing the counter electrode and the end portion of the counter electrode opposite the other electrode. Since the insulation property of the magnetic substrate is prevented from being deteriorated by the discharge, when the ESD is repeatedly applied, the magnetic substrate can be prevented from being electrically conductive and the short-circuit defect can be prevented, and an ESD protection device having high reliability can be provided.

Further, in the ESD protection device of the present invention, since the magnetic substrate is used as the base material on which the counter electrode is formed, a composite member having a filter function and an ESD function can be provided.

Further, in the ESD protection device of the present invention, the protective insulating layer is also disposed between the front end portion of the counter electrode and the front end portion of the counter electrode opposite to the magnetic substrate, and can be surely prevented. The present invention is more effective in terms of conductor formation of a magnetic substrate due to discharge.

Further, another ESD protection device according to the present invention further includes a counter electrode that is connected to one side of the counter electrode and a counter electrode that is opposite to the other side, and that is opposite to the other side from the opposite electrode. Since the discharge auxiliary electrode is disposed in the form of an electrode, excellent discharge characteristics can be obtained, and a protective insulating layer is provided between the discharge auxiliary electrode and the magnetic substrate to prevent deterioration of insulation of the magnetic substrate during discharge, thereby suppressing It is possible to prevent the occurrence of poor magnetic conductors and short-circuit defects, and to provide an ESD protection device with good characteristics and high reliability.

By making the protective insulating layer extend beyond the region in which the discharge auxiliary electrode is formed and disposed in the vicinity thereof, it is possible to surely prevent the magnetic substrate from being electrically conductive due to discharge, and the present invention can be more effective.

Further, in the case where the protective insulating layer contains a crystalline inorganic oxide, it is possible to surely prevent the conductor of the magnetic substrate from being caused by the discharge.

Further, examples of the crystalline inorganic oxide include Al ₂ O ₃ , BaO, CaO, TiO ₂ , CeO, MgO, and ZnO.

Further, in the case where the protective insulating layer contains a glass component, the adhesion between the protective insulating layer and the magnetic substrate can be improved.

Further, in the case where the magnetic substrate contains a glass component, the adhesion between the insulating layer and the magnetic substrate can be improved.

Further, when a cavity portion is provided inside the magnetic substrate and the discharge gap portion faces the cavity portion, discharge can be performed inside the magnetic substrate, and reliability can be improved.

Further, in the case where the discharge portion is located inside the magnetic base material (cavity portion), the inner surface of the cavity portion tends to be deteriorated in insulation, but the protective insulating layer is disposed in the region where the magnetic base material is exposed in the cavity portion. Suppresses insulation degradation and maintains good characteristics.

[Form of ESD protection device of embodiment] (1) A first ESD protection device of an embodiment of the present invention

1 is a cross-sectional view schematically showing the configuration of an ESD protection device A1 of an embodiment of the present invention, and FIG. 2 is a plan view thereof.

As shown in FIGS. 1 and 2, the ESD protection device A1 includes a magnetic substrate 1 including a ferrite, and a counter electrode 2 is attached to the surface of the magnetic substrate 1 and has a front end portion spaced apart from each other. Formed in a facing manner, and the front end portions are configured to be opposite to the side opposite electrode 2a and the other opposite electrode 2b of the discharge gap portion 10 that generates discharge during ESD application; and the protective insulating layer 4 is disposed Preventing the magnetic substrate from being discharged by the discharge on the magnetic substrate 1 constituting the discharge gap portion 10 of the region between the front end portion of the counter electrode 2a and the front end portion of the opposite electrode 2b The insulation is deteriorated. Further, in the first ESD protection device A1, the protective insulating layer 4 is configured to extend from the discharge gap portion 10 to the front end portion of the opposite electrode 2a and the front end portion of the opposite electrode 2b and the magnetic base. The region between the materials 1 is disposed to surely protect the magnetic substrate 1.

Further, the ESD protection device A1 includes external electrodes 5a and 5b which are disposed on the magnetic substrate 1 so as to be electrically connected to the opposite electrode 2a and the other opposite electrode 2b constituting the counter electrode 2. The end is for electrically connecting to the outside.

(2) The second ESD protection device of the embodiment of the present invention

Fig. 3 is a cross-sectional view schematically showing the structure of a second ESD protection device A2 according to an embodiment of the present invention, and Fig. 4 is a plan view thereof.

As shown in FIGS. 3 and 4, the ESD protection device A2 includes a magnetic substrate 1 including a ferrite, and the counter electrode 2 is disposed on the surface of the magnetic substrate 1 so as to be spaced apart from each other at the front end portion. The front end portion is formed to constitute one side opposite electrode 2a and the other opposite electrode 2b, and the discharge auxiliary electrode 3 is connected to each other to form a counter electrode. One side counter electrode 2a and the other side counter electrode 2b are disposed so as to straddle the other side counter electrode 2a and the other side counter electrode 2b; and the protective insulating layer 4 is disposed in the discharge Between the auxiliary electrode 3 and the magnetic substrate 1, the insulation of the magnetic substrate is prevented from being deteriorated by the discharge. Further, in the second ESD protection device A2, the protective insulating layer 4 is disposed so as to protrude beyond the region in which the discharge auxiliary electrode 3 is formed, and is extended to the peripheral region thereof to surely protect the magnetic substrate 1.

Further, the ESD protection device A2 includes external electrodes 5a and 5b which are disposed on the magnetic substrate 1 so as to be electrically connected to the one-side counter electrode 2a and the other counter electrode 2b. The end is for electrically connecting to the outside.

(3) A third ESD protection device of an embodiment of the present invention

Fig. 5 is a view showing the configuration of a third ESD protection device A3 according to an embodiment of the present invention.

The ESD protection device A3 is disposed so as to face the cavity portion 12 provided inside the magnetic substrate 1 so as to constitute the front end portion of the opposite electrode 2a and the other side opposite electrode 2b. The protective insulating layer 4 is disposed on the surface of the magnetic gap 1 exposed in the cavity portion 12 in the discharge gap portion 10 in the region where the tip end portion is sandwiched. Further, the protective insulating layer 4 is also formed to be interposed between the front end electrode 2a and the other end portion of the opposite counter electrode 2b and the magnetic substrate 1.

Further, the ESD protection device A3 includes external electrodes 5a and 5b which are disposed on the magnetic substrate 1 so as to be electrically connected to the opposite electrode 2a and the other opposite electrode 2b constituting the counter electrode 2. Both ends are electrically connected to the outside.

(4) The fourth ESD protection device of the embodiment of the present invention

Further, Fig. 6 is a view showing the configuration of a fourth ESD protection device A4 according to an embodiment of the present invention.

The ESD protection device 4 includes a counter electrode 2 having a distal end portion and a counter electrode 2a and a counter electrode 2b on the other side of the discharge gap portion 10 that generates a discharge when ESD is applied; and a discharge auxiliary electrode 3. The first counter electrode 2a and the other counter electrode 2b are connected to each other, and are disposed so as to straddle the counter electrode 2a from the other side and the counter electrode 2b.

Further, the discharge gap portion 10 is disposed so as to face the cavity portion 12 provided inside the magnetic base material 1, and the protective insulating layer 4 is disposed in a region where the magnetic base material 1 is exposed to the cavity portion 12. Further, the protective insulating layer 4 is also formed to be interposed between the front end electrode 2a and the connecting portion between the front end portion of the other counter electrode 2b and the discharge auxiliary electrode 3 and the magnetic base material 1.

Further, the ESD protection device A4 includes external electrodes 5a and 5b which are disposed on the magnetic substrate 1 so as to be electrically connected to the opposite electrode 2a and the other opposite electrode 2b constituting the counter electrode 2. The end is for electrically connecting to the outside.

Further, in the first to fourth ESD protection devices A1 to A4, as the magnetic substrate 1, a ferrite material containing a glass component is used, which can be sintered at a low temperature, and the protective insulating layer 4 and the magnetic substrate can be improved. 1 closeness.

Further, the protective insulating layer 4 is a layer formed of a material containing a crystalline inorganic oxide and a glass component, and in this embodiment, it contains, for example, Al ₂ O ₃ , BaO, CaO, TiO ₂ , CeO, MgO by heat treatment. And an oxide of ZnO or the like and an insulating paste of the glass frit.

The above-described first to fourth ESD protection devices A1 to A4 are shown, but various configurations may be further included in the scope of the present invention.

In the above-described first to fourth ESD protection devices A1 to A4, the magnetic substrate 1 is not directly exposed to the discharge gap portion 10, but is protected by the protective insulating layer 4, so that in the case where ESD is repeatedly applied, It suppresses and prevents the magnetic substrate from being conductorized and short-circuit defects occur, providing a highly reliable ESD protection device.

Further, in the first and third ESD protection devices, the protective insulating layer 4 is disposed not only in the discharge gap portion 10 but also on the one side opposite electrode 2a and the other side beyond the discharge gap portion 10. Since the region between the front end portion of the counter electrode 2b and the magnetic substrate 1 is prevented, the magnetic base material 1 can be more reliably prevented from being electrified, and the present invention can be more effectively used.

Moreover, since the protective insulating layer 4 contains a crystalline inorganic oxide, even when ESD is repeatedly applied, the magnetic base material can be more reliably prevented from being formed.

Further, since the magnetic base material 1 and the protective insulating layer 4 contain a glass component, the adhesion between the protective insulating layer 4 and the magnetic base material 1 can be improved. Further, as long as at least one of the magnetic base material 1 and the protective insulating layer 4 contains a glass component, the above effects can be obtained.

Further, in the second and fourth ESD protection devices, the protective insulating layer 4 is interposed between the front end electrode 2a and the other end portion of the opposite electrode 2b and the discharge auxiliary electrode 3, Since it is formed between the magnetic base material 1, the magnetic base material 1 can be more reliably prevented from being electrically formed, and the present invention can be made more effective.

Further, in the case of the third and fourth ESD protection devices described above, since the cavity portion 12 is provided inside the magnetic substrate 1, and the discharge gap portion 10 is formed to face the cavity portion 12, it can be inside the magnetic substrate 1. Discharge can improve reliability.

Further, in the case of the third and fourth ESD protection devices, the discharge gap portion 10 is disposed in the cavity portion 12 of the magnetic substrate, and although the inner peripheral surface of the cavity portion tends to be deteriorated in insulation, it is The protective insulating layer 4 is disposed in the region of the magnetic substrate 1 where the cavity portion 12 is exposed, thereby suppressing insulation degradation and maintaining good characteristics.

[Example 1]

Hereinafter, a method of manufacturing the ESD protection device of the present invention will be described, and specific embodiments will be described, and features of the present invention will be described in detail.

Further, in the first embodiment, as shown in FIGS. 3 and 4, the magnetic substrate 1, the counter electrode 2, the discharge auxiliary electrode 3, and the discharge auxiliary electrode 3 and the magnetic substrate 1 are disposed. The ESD protection device (the second ESD protection device described above) that protects the insulating layer 4 and the external electrodes 5a and 5b will be described as an example.

[Manufacture of ESD protection device] (1) Making a magnetic substrate

As the magnetic substrate, a (Ni, Cu, Zn)Fe ₂ O ₄ -based magnetic substrate (ferrite substrate) having a thickness of about 500 μm was prepared. Further, the magnetic substrate was cut into a magnetic substrate 1 having a width of 500 μm and a length of 1000 μm (see FIGS. 3 and 4).

(2) Making the opposite electrode paste

Further, a borosilicate-based glass frit having a mean particle diameter of about 1 μm, 75% by weight of Ag powder, a transition point of 620 ° C, a softening point of 720 ° C, an average particle diameter of about 1 μm, and an ethyl cellulose The counter electrode paste was prepared by dissolving 20% by weight of an organic carrier prepared from terpineol as a counter electrode paste for forming a pair of counter electrodes 2a and 2b by mixing in three rolls.

Further, the average particle diameters of the Cu powder, the borosilicate-based glass frit used in the present embodiment, the following Ag powder, the niobium carbide powder, and various other raw material powders are determined by the particle size distribution measurement of MICROTRAC. The center particle size (D50).

(3) Making discharge auxiliary electrode paste

Preparation of an average particle diameter of about 3 μm, an alumina coating amount of about 5% by weight of Ag powder 50% by weight, an average particle diameter of about 0.5 μm of 5% by weight of niobium carbide powder, and dissolution of ethyl cellulose in terpineol The organic carrier was 45% by weight, and a discharge-assisted electrode paste was prepared by mixing in three rolls as a discharge auxiliary electrode paste for forming the discharge auxiliary electrode 3.

(4) Making an insulating layer paste for forming a protective insulating layer

The borosilicate-based glass frit (GF-1 of Table 3) having an oxide of Table 1, an softening point of 800 ° C and an average particle diameter of about 1 μm, and an organic carrier described in Table 2 were prepared by The insulating layer paste described in Table 3 was produced by mixing in three rolls.

Further, the function of the protective insulating layer suppresses the discharge contact with the magnetic substrate generated at the time of ESD application, thereby suppressing deterioration of the insulation resistance of the magnetic substrate due to the discharge. Therefore, the constituent material of the protective insulating layer is required to be "a material that does not reduce the insulation resistance by contact discharge (≧10 ⁶ Ω)". When the above conditions are satisfied, the constituent material of the protective insulating film is not particularly limited thereto.

As the material constituting the protective insulating layer, for example, a known crystalline inorganic oxide such as alumina or ceria, or a known glass frit such as a boronic acid or borax may be used alone or in combination. Further, from the viewpoint of ensuring the adhesion between the protective insulating layer and the magnetic substrate, it is preferred to use a combination of a crystalline inorganic oxide and a glass frit.

Further, the composition, particle diameter, and softening point of the glass frit used in the present invention are not particularly limited, but usually, the softening point is preferably in the range of 500 ° C to 800 ° C. By using a softening point of 800 ° C or less, it is possible to surely prevent the glass frit from being diffused into the magnetic substrate during firing to deteriorate the magnetic properties of the magnetic substrate, and it is possible to use a softening point of 500 ° C or higher. The adhesion between the protective insulating layer and the magnetic substrate after baking is prevented from deteriorating.

(5) Making external electrode paste

80% by weight of Ag powder having an average particle diameter of about 1 μm, a conversion point of 620 ° C, a softening point of 720 ° C, a borosilicate-based glass frit having an average particle diameter of about 1 μm, 5% by weight, and dissolving ethyl cellulose in An organic carrier prepared from terpineol was 15% by weight, and an external electrode paste was prepared by mixing in three rolls.

(6) Production of various pastes and production of ESD protection devices

As shown in FIG. 7(a), one of the main surfaces of the various magnetic substrates is coated (printed) in the order of the insulating layer paste and the discharge auxiliary electrode paste, and unbaked on the magnetic substrate 1. The protective insulating layer 4 and the unfired discharge auxiliary electrode 3.

Next, as shown in FIG. 7(b), the counter electrode paste is applied to form the unfired counter electrode 2.

Next, the external electrode paste is applied to the surface layer of the laminate by connecting the counter electrodes, and the unfired external electrodes 5a and 5b are formed as shown in Fig. 7(c) to obtain the raw ESD protection device A2.

(7) Roasting

After the fabrication as described above, the raw ESD protection device A2 is fired under atmospheric ambient gas to obtain an ESD protection device A2 having the configuration shown in Figs.

In the first embodiment, at the stage after the firing, the width W of the one side counter electrode 2a and the other side counter electrode 2b constituting the counter electrode 2 is 120 μm, and the size G of the discharge gap 10 is 20 μm. ESD protection device.

Further, in the first embodiment, in order to evaluate the characteristics, the insulating layer pastes P1 to P15 shown in Table 3 were used as the insulating layer paste, and an ESD protection device having the structure shown in Figs. 3 and 4 was produced (Table 4). Samples of sample numbers 1 to 14).

Further, for comparison, an ESD protection device (sample No. 15 of the sample No. 15 of Table 4) which does not have a protective insulating layer was produced.

[Feature evaluation]

Next, regarding each of the ESD protection devices (samples) produced as described above, the characteristics were investigated by the following methods.

(1) Discharge characteristics V peak (Vpeak) and V clamp (Vclamp)

Based on IEC specifications, IEC61000-4-2, at 8 kV contact discharge, from peak voltage value: V peak value, and self-wave head value 30 ns after voltage value: V clamp. The number of applications was 20 times for each sample.

Further, the sample having a maximum value of V peak of less than 500 V was judged to be excellent (?), and a sample of 500 to 900 V was judged to be good (○, and a sample exceeding 900 V was judged to be defective (×).

Further, the sample having a maximum value of V clamp of less than 500 V was judged to be excellent (?), the sample of 500 to 900 V was judged to be good (○), and the sample exceeding 900 V was judged to be defective (×).

(2) Repeated characteristics

The contact discharge of 8 kV was repeated 1000 times, and the resistance value of the ESD protection device after 1000 rounds was measured.

Further, the sample having a resistance value (LogIR value) of more than 6 was judged to be excellent (?), the sample of 3 to 6 was judged to be good (?), and the sample of less than 3 was judged to be defective (x).

(3) Comprehensive evaluation Among the discharge characteristics and the repetitive characteristics, one sample judged as "excellent (◎)" was judged as "excellent (◎)", and one sample judged as "poor (x)" was judged as "poor (X ), the other samples were judged as "good (○)". The results of the above evaluation characteristics are shown in Table 5.

As shown in Table 5, in the ESD protection apparatuses of Sample Nos. 1 to 14 which satisfy the requirements of the present invention and have the protective insulating layers, it was confirmed that the discharge characteristics and the repeat characteristics were all good or not.

In particular, the repetitive characteristics of the ESD protection devices of Sample Nos. 3 to 6 using the protective insulating layer containing the glass component were better than those of the other samples. It is considered that the magnetic base material and the protective insulating layer have high adhesion, and even if ESD is repeatedly applied, the protective insulating layer is hard to be peeled off or scattered from the magnetic base material.

On the other hand, the ESD protection device of the sample No. 15 which does not have the protective insulating layer has poor repeatability, and is comprehensively evaluated as "defective (x)", and cannot be supplied to a practical person. This is presumed to be caused by repeated application of ESD, and the magnetic substrate is electrically formed.

[Embodiment 2]

In the second embodiment, as shown in FIG. 6, the magnetic base material 1, the counter electrode 2, the discharge auxiliary electrode 3, the protective insulating layer 4 disposed between the discharge auxiliary electrode 3 and the magnetic substrate 1, and The external electrodes 5a and 5b and the ESD protection device (the fourth ESD protection device described above) disposed so as to face the cavity portion 12 of the magnetic substrate 1 will be described as an example.

(1) Making magnetic body and bad film

After the calcination, each of the raw materials of the magnetic substrate ((Ni, Cu, Zn) Fe ₂ O ₄ -based magnetic substrate) was prepared into a specific composition, and the calcined powder was obtained by mixing and calcining.

Next, the calcined powder was pulverized in a zirconia ball mill for 12 hours to obtain a ceramic powder (ferrite powder).

An organic solution such as toluene/liquid alcohol is added to the ceramic powder and mixed. Further, a butyral resin, a plasticizer, and a mixture were added to obtain a slurry.

The slurry thus obtained was molded by a doctor blade molding method to obtain a magnetic green sheet having a thickness of 50 μm.

(2) Prepare various pastes

The same paste as in Example 1 was prepared as a counter electrode paste, an insulating layer paste, a discharge auxiliary paste, and an external electrode paste as a counter electrode, a protective insulating layer, a discharge auxiliary electrode, and an external portion. Electrode paste.

Further, as a paste for forming a cavity portion, 38% by weight of crosslinked acrylic resin particles having an average particle diameter of about 1 μm and an organic carrier prepared by dissolving ethyl cellulose in dihydrofurfuryl acetate are prepared. 62% by weight, by mixing in three rolls, a cavity forming paste which was decomposed by the baking step and burned and disappeared was produced.

(3) Printing each paste

On one main surface of the magnetic green sheet 1a produced as described above, as shown in FIG. 8, an insulating layer paste, a discharge auxiliary electrode paste, and a counter electrode paste are applied to form an unfired protective insulating layer. 4. The unfired discharge auxiliary electrode 3 and the unfired counter electrode 2.

Next, as shown in FIG. 9, the resin paste 22 for forming a cavity portion is applied from the unfired counter electrode 2 and the discharge auxiliary electrode 3 in a region where the cavity portion 12 (see FIG. 6) is to be formed, and further, The insulating layer paste is applied to form the unfired protective insulating layer 4 so as to cover the resin paste 22 for forming the cavity portion.

(4) Lamination and crimping

As described above, the magnetic raw sheet for each paste is applied in the order of the insulating layer paste, the discharge auxiliary electrode paste, the counter electrode paste, the resin paste, and the insulating layer paste (the first magnetic body) As shown in Fig. 10, a second magnetic green sheet 1b to which a paste is not applied is laminated, and an unfired laminated body (an unfired ESD protection device not provided with an external electrode) is formed by pressure bonding. After the firing, a laminate having a thickness of 500 μm was formed.

(5) Cutting, coating of external electrode paste

The laminate was cut by a micro cutter and divided into individual wafers. Here, it is cut so as to be 1.0 mm long and 0.5 mm wide after firing. Thereafter, the external electrode paste is applied to the end faces and an unfired external electrode is formed.

(6) Roasting

Next, an ESD protection device having the configuration shown in Fig. 6 was obtained by firing a wafer coated with an external electrode paste in an N ₂ atmosphere.

Further, in the second embodiment, the width of one side counter electrode 2a and the other counter electrode 2b constituting the counter electrode 2 is 120 μm at the stage after firing, and the size of the discharge gap 10 is 20 μm. .

In the second embodiment, in order to evaluate the characteristics, the insulating layer pastes P1 to P15 shown in Table 3 were used as the insulating layer paste, and an ESD protection device having a cavity portion structure as shown in FIG. 6 was produced (sample of Table 6). Sample Nos. 16 to 29).

Further, for comparison, an ESD protection device (sample No. 30 of the sample No. 30 of Table 6) which does not have a protective insulating layer was produced.

[Feature evaluation]

Next, each of the ESD protection devices (samples) produced as described above was measured and evaluated by the following method in the same manner and with reference to the above-described Example 1. The results are shown in Table 6.

In the ESD protection apparatus of Sample Nos. 1 to 14 which provided the protective insulating layer, which satisfies the requirements of the present invention, it was confirmed that the discharge characteristics and the repeatability were both excellent.

In particular, the ESD protection device of Sample Nos. 18 to 21 using a protective insulating layer containing a glass component has better repeatability than the other samples. It is considered that the adhesion between the magnetic substrate and the protective insulating layer is high, and ESD is repeatedly applied, and the protective insulating layer is also difficult to be peeled off or scattered from the magnetic substrate.

On the other hand, the ESD protection device of the sample No. 15 which does not have the protective insulating layer has poor repeatability and cannot be provided to a practical person. It is presumed that the magnetic substrate is electrically formed by repeated application of ESD discharge.

Further, in the above-described first and second embodiments, the ESD protection device having the discharge auxiliary electrode structure as shown in FIGS. 3 and 4 (the first embodiment) and the ESD protection having the cavity portion structure as shown in FIG. 6 are provided. The device is described as an example. However, in the ESD protection device that does not have the discharge auxiliary electrode structure, and the ESD protection device that does not have the discharge auxiliary electrode and the cavity structure, the protective insulating layer is also provided. The ESD protection device of 2 is of good quality.

From the above-described Embodiments 1 and 2, if the effects obtained by the ESD protection device of the present invention are summarized, they are generally as follows.

(a) By providing a structure for protecting the insulating layer, it is possible to prevent the magnetic substrate from being electrically conductive due to repeated discharge of ESD, and it is possible to suppress occurrence of short-circuit defects.

(b) By using a crystalline inorganic oxide as a main component as a protective insulating layer, it is possible to more reliably prevent the magnetic substrate from being electrically conductive due to repeated discharge of ESD, and high reliability can be achieved.

(c) By including the glass component in the protective insulating layer, the adhesion between the magnetic substrate and the insulating layer can be improved, and high repeatability can be achieved.

Further, the present invention is not limited to the above embodiment, and the type and composition of the material constituting the magnetic substrate, the constituent material of the protective insulating layer, the specific shape thereof, the constituent materials of the counter electrode and the discharge auxiliary electrode, and the specific The shape, the shape of the cavity, and the like can be variously changed and changed without departing from the scope of the invention.

1. . . Magnetic substrate

1a. . . The first magnetic body is a bad piece

1b. . . The second magnetic body is a bad piece

2. . . Counter electrode

2a. . . a counter electrode constituting one side of the counter electrode

2b. . . The other opposite counter electrode

3. . . Discharge auxiliary electrode

4. . . Protective insulation

5a. . . External electrode

5b. . . External electrode

10. . . Discharge gap

12. . . Cavity

twenty two. . . Resin paste

A1. . . ESD protection device

A2. . . ESD protection device

A3. . . ESD protection device

A4. . . ESD protection device

G. . . Dimension of discharge gap

W. . . Alignment electrode width

Fig. 1 is a front cross-sectional view showing the configuration of a first ESD protection device according to an embodiment of the present invention in which a discharge gap portion is disposed on a surface of a magnetic substrate.

Fig. 2 is a plan view showing the configuration of the first ESD protection device according to the first embodiment of the present invention in which the discharge gap portion is disposed on the surface of the magnetic substrate.

Fig. 3 is a front cross-sectional view showing the configuration of a second ESD protection device according to an embodiment of the present invention in which a discharge gap portion is disposed on a surface of a magnetic substrate.

Fig. 4 is a plan view showing the configuration of a second ESD protection device according to a second embodiment of the present invention in which a discharge gap portion is disposed on a surface of a magnetic substrate.

Fig. 5 is a front cross-sectional view showing the configuration of a third ESD protection device according to a third embodiment of the present invention in which a discharge gap portion is disposed in a cavity portion of a magnetic substrate.

Fig. 6 is a front cross-sectional view showing the configuration of a fourth ESD protection device according to a fourth embodiment of the present invention in which a discharge gap portion is disposed in a cavity portion of a magnetic substrate.

7(a) to 7(c) are views showing a method of manufacturing the second ESD protection device according to the embodiment of the present invention.

Fig. 8 is a view showing a step of a method of manufacturing the fourth ESD protection device of the fourth embodiment of the present invention.

Fig. 9 is a view showing another step of the method of manufacturing the fourth ESD protection device according to the fourth embodiment of the present invention.

Fig. 10 is a view showing still another step of the method of manufacturing the fourth ESD protection device according to the fourth embodiment of the present invention.

1. . . Magnetic substrate

2. . . Counter electrode

2a. . . a counter electrode constituting one side of the counter electrode

2b. . . The other opposite counter electrode

3. . . Discharge auxiliary electrode

4. . . Protective insulation

5a. . . External electrode

5b. . . External electrode

10. . . Discharge gap

A2. . . ESD protection device

Claims (8)

An electrostatic discharge protection device comprising: a magnetic substrate comprising a glass component; and a counter electrode connected to the surface or the inside of the magnetic substrate, wherein the front end portion is spaced apart from each other and formed to face each other One side opposite electrode and the other opposite electrode, wherein the one side opposite electrode and the other side opposite electrode form a discharge gap portion that generates a discharge when ESD is applied; and a protective insulating layer, It is disposed at least on a surface of the magnetic substrate or in a region facing the discharge gap portion to prevent deterioration of insulation properties of the magnetic substrate due to discharge. The electrostatic discharge protection device according to claim 1, wherein the protective insulating layer is disposed between the front end portion of the one opposite counter electrode and the front end portion of the other opposite counter electrode and the magnetic base material. The electrostatic discharge protection device of claim 1, wherein the protective insulating layer contains a glass component. The electrostatic discharge protection device of claim 1, wherein a cavity portion is provided inside the magnetic substrate, and the discharge gap portion faces the cavity portion. The electrostatic discharge protection device according to claim 4, wherein the protective insulating layer is disposed in a region of the magnetic substrate exposed to the cavity portion. An electrostatic discharge protection device comprising: a magnetic substrate containing a glass component; and a counter electrode attached to a surface or inside of the magnetic substrate, including One side opposite electrode and the other opposite electrode are formed so that the front end portions are spaced apart from each other, and the front end electrode and the other side opposite electrode front end portion are configured to be applied during ESD a discharge gap portion that generates a discharge; and a discharge auxiliary electrode that connects the one side opposite electrode and the other side opposite electrode that constitute the opposite electrode, and the opposite electrode from the one side and the other side The counter electrode is disposed; and the protective insulating layer is disposed between the discharge auxiliary electrode and the magnetic substrate to prevent deterioration of insulation of the magnetic substrate by discharge. The electrostatic discharge protection device of claim 6, wherein the protective insulating layer is disposed in a region beyond a region where the discharge auxiliary electrode is formed and disposed to a periphery thereof. The electrostatic discharge protection device according to any one of claims 1 to 2, wherein the protective insulating layer contains a crystalline inorganic oxide.