TWI427647B - Electrostatic protection parts and manufacturing methods thereof - Google Patents

Description

Electrostatic protection part and manufacturing method thereof

The present invention relates to an electrostatic protection component and a method of manufacturing the same.

In recent years, electronic devices such as mobile information devices are progressing toward miniaturization and high functionality, but with this, the withstand voltage of electronic devices is low. Therefore, electronic devices such as mobile information devices need to use electrostatic protection parts to protect the electronic equipment from overvoltages caused by electrostatic pulses or external noise.

The electrostatic protection component has a positive electrode that faces through the gap and an electrostatic protection film that is provided in the gap, and is provided between the line of the electronic device to which the overvoltage is applied and the ground, and when an overvoltage is applied to the line. The electronic device is protected from the overvoltage by discharging between the aforementioned positive electrodes (ie, the electrostatic protection film).

Further, as a prior art document which discloses a conventional electrostatic protection component, there is, for example, the following Patent Document 1.

[Patent Document] Japanese Laid-Open Patent Publication No. 2009-194130

With the progress of miniaturization and high functionality of electronic devices such as mobile information devices, there is an increasing demand for overvoltage protection functions for electrostatic protection components. Therefore, various characteristics of electrostatic protection components are expected to be improved.

Further, among various characteristics of the electrostatic protection component, the insulation resistance is particularly important. The larger the insulation resistance (ie, the smaller the leakage current), the better, and the smaller the difference in insulation resistance (leakage current) of each part, the better. However, the insulation resistance has a tendency to drop after applying an ESD (Electro Static Discharge) voltage to the electrostatic protection component, and further decreases as the number of times of voltage application increases.

Therefore, in view of the above circumstances, the present invention has been made in an effort to provide an electrostatic protection component and a method of manufacturing the same, in order to minimize the drop in insulation resistance after application of an ESD voltage, and to minimize the difference in insulation resistance of each component.

As a method for solving the above problems, it is roughly classified into a method of developing a structure of an electrostatic protection component, and a method of developing a material of an electrostatic protection film. The present invention has been made in view of the former method and actively studied the result of the construction of the electrostatic protection component, and has the following features.

In other words, the electrostatic protection component according to the first aspect of the invention includes a positive electrode formed on the insulating substrate and facing each other via the first gap, and an insulating film formed on the positive electrode and covering the upper surface of the positive electrode And the two side surfaces are opposed to each other via a second gap that is in contact with the first gap; and the electrostatic protection film has a central portion and both side portions, and the central portion is provided in the first gap and the second gap, and the two The side portion coincides with the upper surface of the foregoing insulating film.

The electrostatic protection component according to the first aspect of the invention is the electrostatic protection component according to the first aspect of the invention, wherein the insulating film is a glass film.

The electrostatic protection component according to the first or second aspect of the invention, wherein the electrostatic protection film is provided with an intermediate layer between the electrostatic protection film and the protective film, and the insulating film is interposed between the intermediate layer and the positive electrode. Between the electrodes.

A method of manufacturing an electrostatic protection component according to a fourth aspect of the invention, characterized in that the method for producing an electrostatic protection component according to the first aspect of the invention includes the first step of forming a film of a positive electrode on an insulating substrate; Forming an insulating film on the film of the electrode, covering the upper surface and the both side surfaces of the film of the positive electrode with the insulating film; cutting the film of the positive electrode formed in the first step and forming the film formed in the second step a third step of forming the first gap and the second gap, and a fourth step of forming the electrostatic protection film, wherein the electrostatic protection film has a shape of a central portion and both side portions, and the central portion is provided at The first gap and the second gap overlap the upper surface of the insulating film.

A method of producing an electrostatic protection component according to a fourth aspect of the invention, wherein the insulating film is a glass film.

A method of manufacturing an electrostatic protection component according to a fourth aspect of the invention, wherein the third step of the third aspect of the invention, wherein the third harmonic laser having a UV wavelength region is used At the same time, the first gap and the second gap are formed by cutting the film of the positive electrode formed in the first step and the insulating film formed in the second step.

The electrostatic protection component according to the first aspect of the invention includes a positive electrode formed on the insulating substrate and facing each other via the first gap, and an insulating film formed on the positive electrode to cover the upper surface and the both side surfaces of the positive electrode. And facing through the second gap connected to the first gap; the electrostatic protection film has a central portion and both side portions, and the central portion is provided in the first gap and the second gap, and the both side portions and the insulating film Since the upper surface overlaps, the positive electrode is provided with an electrostatic protection film only at the first gap between the positive electrodes. That is, the electrostatic protection film is connected to the positive electrode only to the end surface on the gap side, and is not connected to the portion other than the above-mentioned cross section.

Therefore, the electrostatic protection component of the first invention and the electrostatic protection film can also have a very large insulation resistance as compared with the electrostatic protection component to which the positive electrode end face is connected, and the difference in insulation resistance of each component can be made very small. .

According to the electrostatic protection component of the first aspect of the invention, the insulating film is a glass film. Therefore, when the electrostatic protection component is manufactured, heat resistance and insulation can be easily and inexpensively performed. The formation of a glass film.

According to a third aspect of the invention, in the electrostatic protection component of the first aspect or the second aspect of the invention, an intermediate layer is provided between the electrostatic protection film and the protective film, and the insulating film is interposed between the intermediate layer and the positive electrode. Between the electrodes, the intermediate layer is not in contact with the positive electrode by the insulating film. Therefore, the insulating film can be used to surely prevent abnormal discharge generated between the positive electrodes via the intermediate layer. In this case, for example, an intermediate layer can be formed using a material having a relatively low insulating property, so that an effect of expanding the material selection range of the intermediate layer can be obtained.

According to a fourth aspect of the invention, in the method of manufacturing an electrostatic protection component according to the first aspect of the invention, there is provided a first step of forming a film of a positive electrode on an insulating substrate; a second step of forming an insulating film on the film, covering the upper surface and the both side surfaces of the film of the positive electrode with the insulating film; cutting the film of the positive electrode formed in the first step, and the insulating film formed in the second step a third step of forming the first gap and the second gap; having a shape of a central portion and both side portions, wherein the central portion is provided in the first gap and the second gap, and the both side portions are overlapped with the upper surface of the insulating film Since the fourth step of forming the electrostatic protection film is performed, the positive electrode can be provided with the electrostatic protection film only in the first gap between the positive electrodes. In other words, the electrostatic protection film can be formed only by connecting the end surface of the positive electrode to the gap side and not being connected to a portion other than the end surface.

Therefore, the electrostatic protection film produced by the method for producing an electrostatic protection component according to the fourth aspect of the invention can make the insulation resistance extremely large as compared with the electrostatic protection film in which the electrostatic protection film is also partially connected to the end face of the positive electrode. The difference in insulation resistance of each part is very small.

According to the method of manufacturing an electrostatic protection component according to the fifth aspect of the invention, the insulating film is a glass film, and therefore, heat resistance and insulation can be easily and inexpensively performed. The formation of a glass film.

According to a sixth aspect of the present invention, in the method of manufacturing an electrostatic protection component according to the sixth aspect of the present invention, in the third step, the third harmonic having a UV wavelength region can be used. The first gap and the second gap are formed by cutting the film of the positive electrode formed in the first step and the insulating film formed in the second step at the same time, so that the first gap can be easily formed with high precision. And the second gap.

Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

First, the structure of an electrostatic protection component according to an embodiment of the present invention will be described with reference to Figs. 1 to 3 .

The electrostatic protection component 100 shown in FIGS. 1 to 3 is a component for surface mounting on a printed substrate of an electronic device such as a mobile information device, and protects an electronic circuit (electronic component) mounted on the printed substrate from static voltage. An overvoltage caused by a pulse or foreign noise is provided between the line of the aforementioned electronic device and the ground to which the overvoltage is applied.

As shown in FIGS. 1 to 3, positive electrodes 2a and 2b are formed on the surface 1a of the ceramic substrate 1 as an insulating substrate, and back electrodes 3a and 3b are formed on the back surface 1b of the ceramic substrate 1. The positive electrodes 2a and 2b are formed over the entire length of the substrate surface 1a. On the other hand, the back electrodes 3a and 3b are formed at both end portions of the substrate back surface 1b.

A gap (small portion) 4a (first gap) is formed between the positive electrodes 2a and 2b at the central portion of the substrate surface 1a. That is, the positive electrodes 2a and 2b face each other via the gap 4a. The gap 4a is formed by cutting a film of the positive electrode by a cutting means such as a laser method, and has a width d of about 10 μm (in the present embodiment, 7 μm).

Further, a glass film 21a as an insulating film is formed on the positive electrode 2a (near the gap), and a glass film 21b as an insulating film is formed on the positive electrode 2b (near the gap). A gap (small portion) 4b (second gap) is formed between the glass films 21a and 21b. That is, the glass films 21a and 21b oppose each other via the gap 4b. Similarly to the gap 4a, the gap 4b is formed by cutting the glass film by a cutting means such as a laser to have a width d of about 10 μm (7 μm in the present embodiment), and is connected to the gap 4a. The lower layer gap 4a coincides with the upper layer gap 4b.

The end portion 2a-1 on the gap side of the positive electrode 2a, the upper surface 2a-3 thereof, and the both side surfaces 2a-4, 2a-5 (i.e., portions other than the end surface 2a-6 on the gap side) are covered by the glass film 21a (see especially Figure 3 (a)). Similarly, the end portion 2b-1 on the gap side of the positive electrode 2b, the upper surface 2b-3 thereof, and the both side surfaces 2b-4 and 2b-5 (i.e., portions other than the end surface 2b-6 on the gap side) are covered by the glass film 21b ( See especially Figure 3(b)).

An electrostatic protection film 5 is formed on the gaps 4a and 4b, and the electrostatic protection film 5 is connected to the positive electrodes 2a and 2b. Further, since the portion other than the gap-side end surface 2a-6 of the end portion 2a-1 of the positive electrode 2a is covered with the glass film 21a, the electrostatic protection film 5 is connected to the positive electrode 2a only at the end surface 2a-6, and is not connected to the aforementioned end surface 2a- Part of 6 is connected. Similarly, since the portion other than the gap-side end surface 2b-6 of the end portion 2b-1 of the positive electrode 2b is covered with the glass film 21b, the electrostatic protection film 5 is connected to the positive electrode 2b only at the end surface 2b-6, and is not connected to the aforementioned end surface. Part of the connection other than 2b-6.

Specifically, the electrostatic protection film 5 has a T-shaped longitudinal cross-sectional shape (see FIG. 1) and has a central portion 5c and both side portions 5a and 5b. The central portion 5c of the electrostatic protection film 5 is provided in the gaps 4a, 4b as described above (i.e., the gaps 4a, 4b are plugged), and the side portions 5a, 5b of the electrostatic protection film 5 are respectively spaced from the glass films 21a, 21b. The upper faces 21a-2, 21b-2 of the side end portions 21a-1, 21b-1 are overlapped (i.e., the inner ends of the glass films 21a, 21b are covered).

As a result of actively studying the electrostatic protection component, it is preferable that the electrostatic protection film 5 is provided only in the gap 4a between the positive electrodes 2a and 2b in order to minimize the decrease in the insulation resistance after the application of the ESD voltage.

However, in the electrostatic protection component 200 of the comparative example shown in FIG. 4, when the electrostatic protection film is formed directly on the positive electrodes 2a and 2b by the screen printing method without providing a glass film, since the width of the gap 4a is extremely narrow, It is not possible to provide the electrostatic protection film 5 only in the gap 4a, and in any case, it becomes the both side portions 5a, 5b of the electrostatic protection film 5 and the upper portions 2a-1, 2b of the end portions 2a-1, 2b-1 of the positive electrodes 2a, 2b. -3 coincidence status.

Therefore, in the development and manufacturing method of the present invention, as shown in FIG. 1 and the like, after the glass films 21a and 21b are formed on the positive electrodes 2a and 2b, the electrostatic protection film 5 is formed by screen printing from the glass films 21a and 21b. The method. As a result, the electrostatic protection film 5 (center portion 5c) is provided not only in the gaps 4b but also in the glass films 21a and 21b, and the both end portions 5a and 5b of the electrostatic protection film 5 overlap with the upper surfaces of the glass films 21a and 21b. Since the electrodes 2a and 2b block the both end portions 5a and 5b of the electrostatic protection film 5 by the glass films 21a and 21b which are overlapped with the upper surfaces 2a-3 and 2b-3, the electrostatic protection film 5 can be provided only for the gap 4a ( Central Department 5c).

The electrostatic protection film 5 is formed by mixing two kinds of materials, conductive particles and insulating particles, with a ruthenium resin as a binder. The conductive particles and the insulating particles are not subjected to a protective layer provided on the surface of the conductive particles, or a special treatment such as doping other surfaces with the surface of the insulating particles.

Further, the conductive particles are aluminum (Al) powder of conductive metal particles, and the insulating particles are zinc oxide (ZnO) powder. As the zinc oxide powder, zinc oxide having the first insulating property of JIS standard is used, that is, zinc oxide having a volume resistivity of 200 M?cm or more is used. Further, the composition ratio of the three components of the enamel resin, the aluminum powder, and the zinc oxide is 160 parts by weight or more of the aluminum powder, and the zinc oxide powder is 120 parts by weight. In any of the electrostatic protection components 100 and 200 of the present invention and the comparative example, the composition ratio of the electrostatic protection paste satisfies the ESD suppression peak voltage of 500 V or less, and the ESD tolerance (20 voltage application) is a standard value. The target value of the leakage current of 10 μA or less (insulation resistance R = 3 MΩ or more). However, the leakage current of the electrostatic protection component 100 of the present invention is small (refer to FIG. 10, the details will be described later). Therefore, the insulation of the electrostatic protection component 100 of the present invention is further improved. Further, the ESD suppression peak voltage is a voltage generated at the start of discharge.

Upper electrodes 6a and 6b are formed on the positive electrodes 2a and 2b, respectively. Since the positive electrodes 2a and 2b are thin films, the mechanical strength of the positive electrodes 2a and 2b can be enhanced by the upper electrodes 6a and 6b. The upper electrodes 6a and 6b are formed so as not to be in contact with the electrostatic protection film 5 (at a position spaced apart from the electrostatic protection film 5). The reason is that when the upper electrodes 6a and 6b are in contact with the electrostatic protection film 5, when an overvoltage such as an electrostatic pulse is applied to the electrostatic protection component 100, it is not between the positive electrodes 2a and 2b and between the upper electrodes 6a and 6b or the upper electrode. There is a possibility of starting discharge between 6a and 6b and the positive electrodes 2a and 2b. In this case, the original electrostatic protection function of the electrostatic protection component cannot be exhibited.

Further, the glass films 21a and 21b as the insulating film are not formed under the upper electrodes 6a and 6b.

The electrostatic protection film 5 is covered by the intermediate layer 7, and the intermediate layer 7 is covered by the protective film 8. Both end portions 8a, 8b of the protective film 8 are overlapped with one portion (gap side portion) of the upper electrodes 6a, 6b, respectively. Further, the glass films 21a and 21b are interposed not only between the side portions 5a and 5b of the electrostatic protection film 5 but also between the positive electrodes 2a and 2b, and between the intermediate layer 7 and the positive electrodes 2a and 2b.

Since the protective film 8 is excellent in moisture resistance and the like, it is provided to protect the electrostatic protective film 5 and the like by a factor such as an external environment for isolating humidity or the like. However, since the heat resistance of the protective film 8 is insufficient, the electrostatic protective film 5 which generates heat when the discharge is not covered by the protective film 8 is directly covered, and the electrostatic protective film 5 is covered with the intermediate layer 7 having excellent heat resistance, and then the protective film 8 is covered. The intermediate layer 7 is covered.

The intermediate layer 7 also has a function of avoiding abnormal discharge between the positive electrodes 2a and 2b. Further, the intermediate layer 7 is an elastic material (elastomer) to which an inorganic filler such as cerium oxide is added to a resin material such as ruthenium resin, and also has a gap 4a (electrostatic protective film 5) between the positive electrodes 2a and 2b. It suppresses the rise of internal energy (internal pressure) (absorption of the internal energy), and prevents the electrostatic protection component 100 from being damaged due to the impact of the internal energy increase (buffering function).

End surface electrodes 9a and 9b are formed on both end faces 1c and 1d of the ceramic substrate 1, and the positive electrode electrodes 2a and 2b and the back electrodes 3a and 3b are electrically connected to the end face electrodes 9a and 9b, respectively. Further, due to the end portions 9a-1, 9a-2, 9b-1, 9b-2 of the end surface electrodes 9a, 9b, the end portions 2a-2, 2b-2 of the positive electrodes 2a, 2b and the ends of the back electrodes 3a, 3b The portions 3a-1 and 3b-1 are overlapped, respectively, so that the connection between the end electrodes 9a and 9b and the positive electrodes 2a and 2b and the back electrodes 3a and 3b is more reliable.

In addition, in order to improve the reliability of the terminal electrode, the nickel (Ni) plating films 10a and 10b and the tin (Sn) plating films 11a and 11b are sequentially formed on the end surface electrodes 9a and 9b. The nickel plating films 10a and 10b cover the end surface electrodes 9a and 9b, the back electrodes 3a and 3b, a part of the positive electrodes 2a and 2b, and a part of the upper electrodes 6a and 6b, respectively, and the tin films 11a and 11b cover the nickel plating film 10a, respectively. , 10b.

Next, a method of manufacturing the electrostatic protection component 100 according to the embodiment will be described with reference to FIGS. 5 to 8. The S1 to S20 symbols are added to the respective manufacturing steps (Step) of the flowchart of Fig. 5. Further, in FIGS. 6(a) to 6(d), FIGS. 7(a) to 7(d), and Figs. 8(a) to 8(d), the manufacturing state of the electrostatic protection component 100 in each manufacturing step is sequentially displayed.

Further, in the present embodiment, a 1005 type electrostatic protection component 100 (having a width W of 0.5 mm and a length L of 1.0 mm is shown in Fig. 2).

In the first step (step S1), as shown in FIG. 6(a), the ceramic substrate 1 is taken into a manufacturing step (not shown) of the electrostatic protection component 100. Here, an alumina substrate is used as the ceramic substrate 1. This alumina substrate was produced by using 96% alumina as a ceramic material.

In addition, FIG. 6(a) shows only the ceramic substrate 1 of one single-piece region corresponding to the one-piece electrostatic protection component 100, but the actual ceramic substrate 1 before the primary division in step S15 is vertical and horizontal. A plurality of slits and a second slit are formed, and the single-piece region is formed into a plurality of longitudinally and transversely connected sheets.

In the next step (step S2), as shown in Fig. 6 (b), the back electrodes 3a, 3b are formed on the back surface 1b of the ceramic substrate 1. The back electrodes 3a and 3b are formed by applying an electrode paste to the back surface 1b of the substrate and patterning it by a screen printing method. Silver (Ag) paste is used here as an electrode paste. The back electrodes 3a and 3b which are screen-printed are dried to evaporate the solvent in the electrode paste.

In the next step (step S3), as shown in Fig. 6(c), a film of the positive electrode 2 (a film for forming the positive electrodes 2a, 2b in the subsequent step) is formed on the surface 1a of the ceramic substrate 1. The film 2 of the positive electrode is formed by applying an electrode paste on the substrate surface 1a by a screen printing method and patterning it. Here, an Au resinate paste is used as an electrode paste. The film of the positive electrode 2 printed by the screen is dried to evaporate the solvent in the electrode paste.

Further, as the electrode paste for forming the film of the positive electrode 2, a liquid paste (metal organic paste) other than gold may be used. For example, a liquid paste of platinum (Pt) or silver (Ag) or the like can be used. As the electrode paste for forming the back electrodes 3a and 3b, a silver/palladium (Ag/Pd) paste can also be used.

In the next step (step S4), the back electrodes 3a, 3b formed in the step S2 and the positive electrode 2 formed in the step S3 are simultaneously calcined at a temperature of 850 ° C for 40 minutes.

Further, in the next step (step S5), as shown in Fig. 6 (d), a glass film 21 (a film for forming the glass films 21a, 21b in the subsequent step) is formed in the central portion of the positive electrode 2. The glass film 21 is formed by applying a borosilicate glass paste to the positive electrode 2 (to cover the central portion of the positive electrode 2) by pattern printing.

In the next step (step S6), the glass film 21 formed in the step S5 is calcined at a temperature of 600 °C.

In the next step (S7), as shown in Fig. 7(a), the calcined glass film 21 in the processing step S6 is simultaneously cut by using a laser method having a laser (not shown) having a UV wavelength region. The central portion is formed at the same time as the central portion of the positive electrode 2 calcined in step S4, thereby forming a row (overlapping) of the upper layer gap 4b and the lower layer gap 4a. Here, as a laser having a UV wavelength, three high harmonic lasers (wavelength 355 nm) are used. It is assumed that the width d of the gaps 4a and 4b is 7 μm. As a result of forming the gaps 4a and 4b, the pair of positive electrodes 2a and 2b are opposed to each other via the gap 4a, and the pair of glass films 21a and 21b are opposed to each other via the gap 4b.

In the next step (step S8), as shown in FIG. 7(b), a conductive paste is applied to each of the positive electrodes 2a, 2b by a screen printing method and patterned, thereby forming over the positive electrodes 2a, 2b. Upper electrodes 6a, 6b. The number of screen printings at this time is one. In order to prevent the upper electrodes 6a and 6b from coming into contact with the electrostatic protection film 5, the upper electrodes 6a and 6b are formed so as to overlap with the positive electrodes 2a and 2b at positions spaced apart from the electrostatic protection film 5. After the screen printing, the upper electrodes 6a and 6b are dried to evaporate the solvent in the conductive paste.

The screen used in the screen printing has a mesh size of 400 and an emulsion thickness of 8 ± 2 μm (model: st 400).

Further, as the conductive paste, silver powder and epoxy resin are kneaded. Further, it is not limited thereto, and a thick film electrode paste obtained by kneading nickel (Ni), copper (Cu) powder or the like with an epoxy resin may be used as the conductive paste for the upper electrode.

In the next step (step S9), as shown in FIG. 7(c), the electrostatic protection paste is applied to the gaps 4a and 4b by a screen printing method and patterned to form the electrostatic protection film 5. At this time, the electrostatic protection film 5 has a shape having a central portion 5c and both side portions 5a and 5b. The central portion 5c of the electrostatic protection film 5 is provided only in the gap 4a (blocking gap 4a) and is connected to the positive electrodes 2a and 2b with respect to the positive electrodes 2a and 2b, and the central portion of the electrostatic protective film 5 with respect to the glass films 21a and 21b. 5c is provided in the gap 4b (blocking gap 4b), and both end portions 5a and 5b of the electrostatic protection film 5 overlap with one of the upper surfaces 21a-2 and 21b-2 of the glass films 21a and 21b (end portions on the gap side).

The electrostatic protection film 5 after screen printing was dried at a temperature of 100 ° C for 10 minutes to evaporate the solvent in the paste for electrostatic protection.

Further, the screen-printed flat mesh used in the screen printing has a mesh size of 400, a wire diameter of 18 μm, and an emulsion thickness of 5 ± 2 μm (model: cal 1400/18).

In the electrostatic protection paste used herein, a binder of a ruthenium resin is used as a base material, and the aluminum powder used as the conductive particles and the zinc oxide powder used as the insulating particles are kneaded with the ruthenium resin. Adult. In addition, when the composition ratio of the three components is 100 parts by weight of the cerium resin, the aluminum powder is 160 parts by weight, and the zinc oxide powder is 120 parts by weight. In this case, the ESD suppression leakage power is 500 V or less, ESD. The target value of the leakage current of the standard value is 10 μA or less (insulation resistance R=3 MΩ or more).

Further, as the oxime resin, an additional reaction type ruthenium resin having a volume resistivity of 2 × 10 ¹⁵ Ωcm and a dielectric constant of 2.7 was used.

As the aluminum powder, aluminum powder having an average particle diameter of 3.0 to 3.6 μm which is obtained by melting aluminum, high-pressure spraying, and solidifying is used.

As the zinc oxide powder, zinc oxide having the first insulating property (volume resistivity: 200 MΩcm or more) having a JIS standard is used. Further, the zinc oxide powder uses zinc oxide powder having a particle size distribution of 0.3 to 1.5 μm, an average particle diameter of 0.6 μm, and a primary agglomerated particle size of 1.5 μm.

In the next step (step S10), the upper electrodes 6a, 6b and the electrostatic protection film 5 formed in the step S9 are simultaneously formed in the calcination step S8 at a temperature of 200 ° C for 30 minutes.

In the next step (step S11), as shown in FIG. 7(d), the silicone resin paste is applied to the electrostatic protection film 5 and the glass films 21a and 21b by pattern printing, and patterned to form an electrostatic protection layer. 5th intermediate layer 7. The number of screen printings at this time is one.

Here, as the enamel resin paste, a bismuth resin paste containing 40 to 50% of cerium oxide is used.

In addition, the screen-printed flat mesh used in the screen printing has a mesh size of 400, a wire diameter of 18 μm, and an emulsion thickness of 5 ± 2 μm (model: cal 1400/18).

In the next step (step S12), the intermediate layer 7 formed in the step S11 is calcined at a temperature of 150 ° C for 30 minutes.

In the next step (step S13), as shown in FIG. 8(a), an epoxy resin paste is applied to the intermediate layer 7, the glass films 21a and 21b, the positive electrodes 2a and 2b, and the upper electrode 6a by a screen printing method. 6b is patterned and thereby forms a protective film 8 covering the intermediate layer 7 and the like. At this time, the number of screen printing is 2 times.

Further, the screen printing used in the screen printing has a mesh size of 400 and an emulsion thickness of 10 ± 2 μm (model: 3D Sus 400/19).

In the next step (step S14), the protective film 8 formed in the step S13 is calcined at a temperature of 200 ° C for 30 minutes.

In the next step (step S15), the ceramic substrate 1 is divided once along the first slit formed in the sheet-like ceramic substrate 1. As a result, the ceramic substrate 1 is a band in which a plurality of single-piece regions are laterally connected in a row, and end faces 1c and 1d are produced.

In the next step (step S16), as shown in FIG. 8(b), a conductive paste is applied to the end faces 1c and 1d of the ceramic substrate 1, a portion of the positive electrodes 2a and 2b, and the back electrode 3a by a transfer method. One of the portions 3b is calcined at a temperature of 200 ° C for 30 minutes in the next step (S17), whereby the end surface electrodes 9a, 9b are formed. At this time, the end surface electrodes 9a and 9b partially overlap the positive electrodes 2a and 2b and the back electrodes 3a and 3b, and the positive electrodes 2a and 2b are electrically connected to the back electrodes 3a and 3b.

Here, as the conductive paste, a paste obtained by kneading silver powder and epoxy resin is used.

In the next step (step S18), the ceramic substrate 1 is divided twice along the second slit formed in the strip-shaped ceramic substrate 1. As a result, the ceramic substrate 1 is divided into a single piece in each of the individual piece regions.

In the next step (step S19), as shown in Fig. 8(c), a portion of the end surface electrodes 9a, 9b, the back electrodes 3a, 3b, the positive electrodes 2a, 2b, and a portion of the upper electrodes 6a, 6b are plated by a barrel plating method. Electroplating is performed thereon to form nickel plating films 10a and 10b.

In the final step (step S20), as shown in FIG. 8(d), plating is performed on the nickel plating films 10a and 10b formed in step S19 by a barrel plating method to form tin plating films 11a and 11b. Thus, the electrostatic protection component 100 is completed.

Next, the results of the ESD test performed on the electrostatic protection component 100 (FIG. 1) having the glass films 21a and 21b of the present invention and the electrostatic protection component 200 without the glass film of the comparative example will be described based on FIG. 9 and FIG. .

The ESD test is performed by applying the ESD voltage to the electrostatic protection components 100 and 200 based on IEC61000-4-2 8 kV.

With respect to the electrostatic protection component 100 of the present invention, 10 samples were prepared in the same manufacturing steps as described above, and for the electrostatic protection component 200 of the comparative example, 10 samples were prepared in the same manufacturing procedure as above except that there was no glass film. . And 20 times of ESD voltage was applied to any of the samples.

Fig. 9(a) shows the measurement result of the ESD suppression peak voltage when the first ESD voltage is applied to the sample of the electrostatic protection component 100 of the present invention, and Fig. 9(b) shows the application of the sample of the electrostatic protection component 200 of the comparative example. The measurement result of the ESD suppression peak voltage at the first ESD voltage.

From the results of these measurements, it was found that any of the samples satisfies the target value of 500 V or less in terms of the ESD suppression peak voltage, and no significant differential pressure between the two samples was observed.

On the other hand, Fig. 10(a) shows the results of measuring the leakage current after applying the first, tenth and 20th ESD voltages to the sample of the electrostatic protection component 100 of the present invention, and Fig. 10(b) shows the pair. The result of the leakage current was measured after the 20th ESD voltage was applied to the sample of the electrostatic protection component 200 of the comparative example.

Further, as shown in FIG. 10(a), in the electrostatic protection component 100 of the present invention, the leakage current is 0.001 μA after application of any of the first, tenth, and twentyth ESD voltages of any of the samples. Very small value, and there is no difference in leakage current for each sample (part). That is, it can be confirmed that the insulation resistance of any of the samples is very large, and there is no difference in the insulation resistance of each sample.

On the other hand, as shown in FIG. 10(b), in the electrostatic protection component 200 of the comparative example, although any of the samples satisfies the target value of 10 μA or less, the leakage current is found as compared with the result of FIG. 10(a). There are many samples, and the difference in leakage current of each sample is very large. That is, it can be confirmed that the insulation resistances of these samples are relatively small, and the difference in insulation resistance of each sample is also large.

Further, the structures of the glass films 21a and 21b are not limited to those shown in FIGS. 1 to 3, and may be, for example, a structure as shown in FIGS. 11 to 13 or a structure shown in FIGS. 14 and 15.

Specifically, the electrostatic protection component 300 shown in FIGS. 11 to 13 is larger than the electrostatic protection component 100 shown in FIGS. 1 to 3 (see FIGS. 2 and 3 in particular), and the widths of the glass films 21a and 21b become larger. (In particular, referring to Figs. 12 and 13, the upper and lower directions of the figures are the width directions of the glass films 21a and 21b).

Specifically, as shown in FIGS. 2 and 3, the glass films 21a and 21b of the electrostatic protection component 100 are larger than the widths of the positive electrodes 2a and 2b, but smaller than the width of the electrostatic protection film 5, and cover the positive electrode 2a. The two side faces 2a-4, 2a-5 or the two side faces 2b-4, 2b-5 of the positive electrode 2b have the side faces 2a-4, 2a-5, 2b-4, 2b-5 and the electrostatic protection film 5 Connect to the minimum width. On the other hand, as shown in FIGS. 12 and 13, the glass films 21a and 21b of the electrostatic protection component 300 have a width larger than the widths of the positive electrodes 2a and 2b, the width of the electrostatic protection film 5, and the width of the intermediate layer 7. The width of the big.

Further, the other configuration of the electrostatic protection component 300 is the same as that of the electrostatic protection component 100. Furthermore, the method of manufacturing the electrostatic protection component 300 is also the same as the manufacturing method of the electrostatic protection component 100.

The structure of the K-K line arrow direction cross section and the L-L line arrow direction cross section of Fig. 14 is the same as the cross section shown in Fig. 3 (a) and the cross section shown in Fig. 3 (b), and therefore Fig. 3 is referred to.

As shown in FIGS. 3, 14, and 15, the electrostatic protection component 400 is shorter than the electrostatic protection component 100 shown in FIGS. 1 to 3 (see FIGS. 1 and 2 in particular), and the lengths of the glass films 21a and 21b are shortened. (In particular, referring to Figs. 14 and 15, the left and right directions of the figures are the longitudinal directions of the glass films 21a and 21b).

Specifically, as shown in FIGS. 1 and 2, the glass films 21a and 21b of the electrostatic protection component 100 are longer than the length of the electrostatic protection film 5 and the length of the intermediate layer 7. On the other hand, as shown in FIG. 14 and FIG. 15, the glass films 21a and 21b of the electrostatic protection component 400 are longer than the length of the electrostatic protection film 5, but are shorter than the length of the intermediate layer 7, and are interposed between the electrostatic protection film 5 The side portions 5a, 5b and the positive electrodes 2a, 2b (i.e., the surfaces 2a-3, 2b-3 covering the end portions 2a-1, 2b-1 of the positive electrodes 2a, 2b) have two of the electrostatic protection films 5 The minimum length at which the side portions 5a, 5b are in contact with the positive electrodes 2a, 2b.

Further, the other configuration of the electrostatic protection component 400 is the same as that of the electrostatic protection component 100. Furthermore, the method of manufacturing the electrostatic protection component 400 is also the same as the manufacturing method of the electrostatic protection component 100.

As described above, the electrostatic protection components 100, 300, and 400 according to the present embodiment are characterized in that the positive electrodes 2a and 2b are formed on the ceramic substrate 1 and face each other via the gap 4a; the glass films 21a and 21b are formed. Formed on the positive electrodes 2a, 2b, covering the upper faces 2a-3, 2b-3 of the positive electrodes 2a, 2b and the two side faces 2a-4, 2a-5, 2b-4, 2b-5, and connected to the gap 4a The electrostatic protection film 5 has a central portion 5c and both side portions 5a, 5b, and the central portion 5c is provided in the gap 4a and the gap 4b, and the both side portions 5a, 5b and the upper surfaces of the glass films 21a, 21b Since 21a-2 and 21b-2 are overlapped, the positive electrode 2a and 2b are provided with the electrostatic protection film 5 (center portion 5c) only in the gap 4a between the positive electrodes 2a and 2b. In other words, the electrostatic protection film 5 is in contact with the positive electrodes 2a and 2b only at the end faces 2a-6 and 2b-6 on the gap side, and is not in contact with portions other than the end faces 2a-6 and 2b-6.

Therefore, compared with the electrostatic protection film 5 in which the electrostatic protection film 5 is also in contact with the portion other than the end faces of the positive electrodes 2a and 2b, the electrostatic protection film 100 can make the insulation resistance very large, and the insulation resistance of each component can be made. The difference is very small.

Further, according to the electrostatic protection components 100, 300, and 400, the insulating film is made of the glass films 21a and 21b. Therefore, when the electrostatic protection component 100 is manufactured, the formation of the heat-resistant and insulating glass film can be easily and inexpensively performed. .

Further, according to the electrostatic protection components 100, 300, since the glass films 21a, 21b are interposed between the intermediate layer 7 and the positive electrodes 2a, 2b, the intermediate layer 7 is not connected to the positive electrode by the glass films 21a, 21b. 2a, 2b contact. Therefore, abnormal discharge can be prevented from occurring between the positive electrodes 2a and 2b via the intermediate layer 7 by the glass films 21a and 21b. In this case, for example, the intermediate layer 7 may be formed of a material having a relatively low insulating property, so that the effect of the material selection range of the intermediate layer 7 is wide.

Further, according to the method for manufacturing the electrostatic protection component 100 of the present embodiment, the first step of forming the film of the positive electrode 2 on the ceramic substrate 1 is formed, and the insulating film 21 is formed on the film of the positive electrode 2, a second step of covering the upper surface and the both side surfaces of the film of the positive electrode 2 by the insulating film 21; cutting the film of the positive electrode 2 formed in the first step and the glass 21 formed in the second step to form a gap The third step of 4a and the gap 4b; and the fourth step of forming the electrostatic protection film 5, the electrostatic protection film 5 having the shape of the central portion 5c and the side portions 5a, 5b, and the central portion 5c is disposed in the gap 4a and the gap 4b, and the two side portions 5a, 5b are overlapped with the upper surfaces 21a-2, 21b-2 of the glass films 21a, 21b. Therefore, for the positive electrodes 2a, 2b, only between the positive electrodes 2a, 2b The electrostatic protection film 5 (center portion 5c) is provided in the gap 4a. That is, the electrostatic protection film 5 can be formed by contacting the positive electrodes 2a and 2b only at the end faces 2a-6 and 2b-6 on the gap side without contacting the portions other than the end faces 2a-6 and 2b-6. .

Therefore, compared with the electrostatic protection component 200 in which the electrostatic protection film 5 is also in contact with a portion other than the end faces of the positive electrodes 2a and 2b, the electrostatic protection component 100 manufactured according to the present manufacturing method can make the insulation resistance very large and can be made The difference in insulation resistance of each part is very small.

Further, according to the present manufacturing method, since the insulating film-based glass films 21a and 21b are provided, the formation of the heat-resistant and insulating glass films 21a and 21b can be easily and inexpensively performed.

Further, according to the manufacturing method, in the third step, the third-order harmonic laser having a UV wavelength is used, and the film of the positive electrode 2 formed in the first step and the second portion are cut simultaneously Since the glass film 21 formed in the step forms the gaps 4a and 4b, the gaps 4a and 4b can be formed easily and with high precision.

Furthermore, the embodiment in which the electrostatic protection component of the one electrostatic protection film 5 is formed on one ceramic substrate 1 has been described above, but the invention is not limited thereto. The electrostatic protection component in which two or more electrostatic protection films 5 are formed on one ceramic substrate 1 is also included in the scope of the present invention.

Further, although the above description has been made on the formation of an electrostatic protective film using a paste obtained by kneading three components of an anthraquinone resin and an aluminum powder and a zinc oxide powder, the present invention is not limited thereto, and the structure of the electrostatic protection component of the present invention can also be applied. An electrostatic protection component that forms an electrostatic protection film with a material different from the above.

[Industrial availability]

The present invention relates to an electrostatic protection component and a method of manufacturing the same, and is useful for improving the insulation resistance characteristics of an electrostatic protection component.

1. . . Ceramic substrate

1a. . . Substrate surface

1b. . . Back side of substrate

1c, 1d. . . Substrate end face

2. . . Positive electrode film

2a, 2b. . . Positive electrode

2a-1, 2a-2, 2b-1, 2b-2. . . End of positive electrode

2a-3, 2b-3. . . Above the positive electrode

2a-4, 2a-5, 2b-4, 2b-5. . . Side of the positive electrode

2a-6, 2b-6. . . End face of positive electrode

3a, 3b. . . Back electrode

3a-1, 3b-1. . . End of the back electrode

4a, 4b. . . gap

5. . . Electrostatic protective film

5a, 5b. . . Side of electrostatic protection film

5c. . . Central part of electrostatic protection film

6a, 6b. . . Upper electrode

7. . . middle layer

8. . . Protective film

8a, 8b. . . End of protective film

9a, 9b. . . End electrode

9a-1, 9a-2, 9b-1, 9b-2. . . End of the end electrode

10a, 10b. . . Nickel plating

11a, 11b. . . Tin plating film

21, 21a, 21b. . . glass film

21a-1, 21b-1. . . End of glass film

21a-2, 21b-2. . . Above the glass film

100. . . Electrostatic protection parts (with glass film)

200. . . Electrostatic protection parts (no glass film)

300. . . Electrostatic protection parts (with glass film)

400. . . Electrostatic protection parts (with glass film)

Fig. 1 is a cross-sectional view showing a structure of an electrostatic protection component according to an embodiment of the present invention (a cross-sectional view taken along line B-B of Fig. 2).

Fig. 2 is a top view showing the structure of an electrostatic protection component according to an embodiment of the present invention (an arrow direction in the direction of arrow A in Fig. 1).

3(a) is a cross-sectional view taken along the line CC of FIG. 1, and (b) is a cross-sectional view taken along the line D _- D of FIG.

Fig. 4 is a cross-sectional view showing the structure of an electrostatic protection component of a comparative example.

Fig. 5 is a flow chart showing the steps of manufacturing the electrostatic protection component according to the embodiment of the present invention.

6(a) to 6(d) are first explanatory views showing the steps of manufacturing the electrostatic protection component according to the embodiment of the present invention.

Fig. 7 (a) to (d) are second explanatory views showing the steps of manufacturing the electrostatic protection component according to the embodiment of the present invention.

8(a) to 8(d) are third explanatory views showing the steps of manufacturing the electrostatic protection component according to the embodiment of the present invention.

Fig. 9 (a) is a table showing the results of measurement of the ESD suppression peak voltage of the electrostatic protection component (with glass film) of the present invention (Example), and (b) shows the ESD of the electrostatic protection component (without glass film) of the comparative example. A table for suppressing the peak voltage measurement result.

Fig. 10 (a) is a table showing measurement results of leakage current of the electrostatic protection component (with glass film) of the present invention (Example), and (b) is a table showing measurement results of leakage current of the electrostatic protection component of the comparative example.

Fig. 11 is a cross-sectional view showing another structural example (a structural example of a glass film portion) of the electrostatic protection component according to the embodiment of the present invention (the arrow direction of the F-F line in Fig. 12).

Fig. 12 is a top view showing an example of another structure (a configuration example of a glass film portion) of an electrostatic protection component according to an embodiment of the present invention (an arrow direction in the direction of E in Fig. 11).

Fig. 13 (a) is a cross-sectional view taken along the line G-G of Fig. 11 and (b) is a cross-sectional view taken along the line H-H of Fig. 11;

Fig. 14 is a cross-sectional view showing another structural example (a structural view of a glass film portion) of the electrostatic protection component according to the embodiment of the present invention (a cross-sectional view taken along the line J-J in Fig. 15).

Fig. 15 is a top view (an arrow direction of the I direction of Fig. 14) showing another structural example (a structural view of a glass film portion) of the electrostatic protection component according to the embodiment of the present invention.

1. . . Ceramic substrate

1a. . . Substrate surface

1b. . . Back side of substrate

1c, 1d. . . Substrate end face

2a, 2b. . . Positive electrode

2a-1, 2a-2, 2b-1, 2b-2. . . End of positive electrode

2a-3, 2b-3. . . Above the positive electrode

2a-6, 2b-6. . . End face of positive electrode

3a, 3b. . . Back electrode

3a-1, 3b-1. . . End of the back electrode

4a, 4b. . . gap

5. . . Electrostatic protective film

5a, 5b. . . Side of electrostatic protection film

5c. . . Central part of electrostatic protection film

6a, 6b. . . Upper electrode

7. . . middle layer

8. . . Protective film

8a, 8b. . . End of protective film

9a, 9b. . . End electrode

9a-1, 9a-2, 9b-1, 9b-2. . . End of the end electrode

10a, 10b. . . Nickel plating

11a, 11b. . . Tin plating film

21a, 21b. . . glass film

21a-1, 21b-1. . . End of glass film

21a-2, 21b-2. . . Above the glass film

100. . . Electrostatic protection parts (with glass film)

Claims (6)

An electrostatic protection component comprising: a positive electrode formed on an insulating substrate and facing each other via a first gap; an insulating film formed on the positive electrode covering the upper surface and both sides of the positive electrode, and The electrostatic protection film has a central portion and both side portions, and the central portion is provided in the first gap and the second gap, and the both sides are insulated from the foregoing The top of the film coincides. The electrostatic protection component of claim 1, wherein the insulating film is a glass film. The electrostatic protection component of claim 1 or 2, wherein an intermediate layer is disposed between the electrostatic protection film and the protective film, and the insulating film is interposed between the intermediate layer and the positive electrode. A method of manufacturing an electrostatic protection component, comprising the method of manufacturing the electrostatic protection component of claim 1, comprising: a first step of forming a film of a positive electrode on the insulating substrate; forming on the film of the positive electrode a second step of covering the upper surface and the both side surfaces of the film of the positive electrode by the insulating film; cutting the film of the positive electrode formed in the first step and the insulating film formed in the second step to form an insulating film a third step of forming the first gap and the second gap; and a fourth step of forming the electrostatic protection film, wherein the electrostatic protection film has a shape of a central portion and both side portions, and the central portion is provided in the first gap and the first portion 2 gaps, and the two side portions are overlapped with the upper surface of the insulating film. A method of producing an electrostatic protection component according to claim 4, wherein the insulating film is a glass film. The method of manufacturing the electrostatic protection component according to claim 4 or 5, wherein in the third step, a third harmonic laser having a UV wavelength region is used, and the film of the positive electrode formed in the first step is cut off simultaneously The insulating film formed in the second step described above forms the first gap and the second gap.