JP5614563B2 - Manufacturing method of ESD protection device - Google Patents

Description

The present invention relates to a method of manufacturing an ESD protection device that protects a semiconductor device or the like from electrostatic breakdown.

  In recent years, when using consumer equipment, the number of insertion / removal of cables as input / output interfaces tends to increase, and static electricity is likely to be applied to the input / output connector section. Further, along with the increase in signal frequency, it becomes difficult to create a path due to miniaturization of design rules, and the LSI itself is vulnerable to static electricity.

  Therefore, ESD protection devices for protecting semiconductor devices such as LSIs have been widely used from electrostatic discharge (ESD) (Electron-Statistics Discharge).

  As such an ESD protection device, an ESD protection device (chip type) including an insulating chip body having a sealed space in which an inert gas is sealed in the center, a counter electrode having a micro gap on the same surface, and an external electrode. A surge absorber) and a method for manufacturing the same have been proposed (see Patent Document 1).

  However, in the ESD protection device (chip-type surge absorber) of Patent Document 1, since it is necessary for electrons to jump directly between the micro gaps of the counter electrode without any assistance, the discharge capability depends on the micro gap width. To do. And, as the microgap becomes narrower, the ability as a surge absorber becomes higher, but in order to form the counter electrode using a printing method as described in Patent Document 1, there is a limit to the gap formable width, If it is too narrow, there is a problem that the counter electrodes are connected to each other to cause a short circuit defect.

  In addition, as described in Patent Document 1, since a cavity is formed by stacking sheets with holes, it is necessary to dispose a micro gap in the cavity. Therefore, there is a limit to the miniaturization of products from the viewpoint of stacking accuracy. Furthermore, in order to obtain a configuration in which the sealed space is filled with the enclosed gas, it is necessary to perform lamination pressure bonding under the enclosed gas during lamination, which complicates the manufacturing process, lowers productivity, and increases costs. There is a problem of doing.

In addition, as another ESD protection device, an ESD protection device in which an internal electrode and a discharge space that are electrically connected to the external electrode are provided in an insulating ceramic layer having a pair of external electrodes, and a discharge gas is confined in the discharge space. (Surge absorbing element) and its manufacturing method are proposed (refer patent document 2).
However, the ESD protection device of Patent Document 2 also has the same problem as that of the ESD protection device of Patent Document 1.

Further, as another ESD protection device, a ceramic multilayer substrate, at least a pair of discharge electrodes formed on the ceramic multilayer substrate and facing each other at a predetermined interval, and formed on the surface of the ceramic multilayer substrate, the discharge electrode An ESD protection device having an external electrode connected to an ESD protection device having an auxiliary electrode in which a conductive material coated with an inorganic material having no conductivity is dispersed in a region connecting a pair of discharge electrodes A protection device has been proposed (see Patent Document 3).
However, in the case of this ESD protection device, the glass component in the ceramic multilayer substrate penetrates into the discharge auxiliary electrode in the firing step at the time of manufacture, and the conductive material of the discharge auxiliary electrode becomes oversintered, resulting in a short circuit defect. There is a problem.

Japanese Patent Laid-Open No. 9-266053 JP 2001-43954 A Japanese Patent No. 4434314

The present invention has been made in view of the above circumstances, and provides a method for manufacturing an ESD protection device that is excellent in discharge capability but has few short-circuit defects and does not require a special process during manufacturing, and has excellent productivity. The purpose is to do.

In order to solve the above problems, a method for manufacturing an ESD protection device of the present invention includes:
Printing a seal layer paste on one main surface of the first ceramic green sheet to form an unfired seal layer;
Printing a discharge auxiliary electrode paste so as to cover at least a part of the sealing layer to form an unfired discharge auxiliary electrode;
A counter electrode paste is printed on one main surface of the first ceramic green sheet, each covering a part of the discharge auxiliary electrode, and one side counter electrode disposed at a distance from each other; Forming an unfired counter electrode comprising the other counter electrode;
A step of laminating a second ceramic green sheet on the other main surface of the first ceramic green sheet to form an unfired laminate;
And firing the laminate.
At the interface between the sealing layer and the first ceramic green sheet, a reaction layer containing a reaction product generated by a reaction between the constituent material of the sealing layer and the constituent material of the first ceramic green sheet is formed. And
The difference ΔB (= B1−B2) between the basicity B1 of the main constituent material of the sealing layer and the basicity B2 of the amorphous part constituting the first ceramic green sheet is 1.33 or less. It is a feature.

As described above, the method for manufacturing an ESD protection device of the present invention includes a step of printing a seal layer paste on the first ceramic green sheet to form an unfired seal layer, and covering a part of the seal layer. A discharge auxiliary electrode paste is printed on the substrate to form an unfired discharge auxiliary electrode, and a counter electrode paste is printed, each covering a part of the discharge auxiliary electrode and spaced apart from each other. A step of forming an unfired counter electrode including the provided one side counter electrode and the other side counter electrode, and laminating a second ceramic green sheet on one main surface of the first ceramic green sheet It has a process of forming a fired laminate and a process of firing the laminate, and each process is a general-purpose process widely used in the manufacturing process of ordinary ceramic electronic components, and is excellent in mass productivity. To have. In addition, a seal layer is formed between the ceramic substrate and the discharge auxiliary electrode, and a constituent material of the seal layer and a constituent material of the first ceramic green sheet are formed at the interface between the seal layer and the first ceramic green sheet. A reaction layer containing the reaction product generated by the reaction is formed, and the difference ΔB between the basicity B1 of the main constituent material of the seal layer and the basicity B2 of the amorphous part constituting the first ceramic green sheet Since (= B1-B2) is 1.33 or less, the discharge auxiliary electrode is isolated from the ceramic constituting the ceramic substrate by the seal layer. It is possible to reliably prevent the occurrence of short-circuit defects due to sintering and to ensure stable discharge performance.

  In addition, in the manufacturing method in the case of manufacturing the ESD protection device of the present invention, an external electrode paste is printed on the surface of the unfired laminate so as to be connected to the counter electrode before the step of firing the laminate. Then, it is possible to obtain an ESD protection device having an external electrode by firing once, and after the firing of the laminate, an external electrode paste is applied to the surface of the laminate. It is also possible to form external electrodes by printing and baking.

In the ESD protection device manufactured by the method of the present invention, the glass component is discharged through the counter electrode by interposing a seal layer between the connecting portion between the counter electrode and the discharge auxiliary electrode and the ceramic substrate. It becomes possible to suppress and prevent the penetration into the auxiliary electrode, and the present invention can be made more effective.

  In addition, since the reaction layer containing the reaction product generated by the reaction between the constituent material of the sealing layer and the constituent material of the ceramic base material is provided at the interface between the sealing layer and the ceramic base material, the formed sealing layer Even in the case of a product that is fired at a temperature lower than the melting point of the main component, it is possible to provide a highly reliable product in which the seal layer is in close contact with the ceramic material constituting the ceramic substrate.

  Further, since the difference ΔB (= B1−B2) between the basicity B1 of the main constituent material of the seal layer and the basicity B2 of the amorphous part of the ceramic base material is 1.33 or less, that is, In addition, by defining the basicity difference as described above, an excessive reaction and an under reaction between the seal layer and the ceramic substrate are suppressed, and a reaction layer that does not hinder the function as an ESD protection device is provided. A highly reliable ESD protection device can be provided.

  In addition, when the seal layer has an element contained in the ceramic substrate as a part thereof, it becomes possible to suppress an excessive reaction between the seal portion and the ceramic substrate, and ESD with good characteristics. A protection device can be provided.

  In addition, when aluminum oxide is used as the main component of the seal layer, it is possible to obtain a bond without excess / underreaction between the seal part and the ceramic substrate, and glass from the ceramic substrate. Can be reliably prevented in the seal layer, and the occurrence of short-circuit defects due to the glass component flowing into the discharge auxiliary electrode and sintering can be suppressed and prevented.

  In addition, since the discharge auxiliary electrode includes metal particles and a ceramic component, the ceramic component is interposed between the metal particles, and the metal particles are positioned at an interval corresponding to the presence of the ceramic component. Therefore, in the step of forming the discharge auxiliary electrode by firing the discharge auxiliary electrode paste, the sintering of the discharge auxiliary electrode is relaxed, and the occurrence of short-circuit defects due to the discharge auxiliary electrode being excessively sintered is suppressed and prevented. Can do. Moreover, the excessive reaction with a sealing layer can be suppressed by including a ceramic component.

It is front sectional drawing which shows typically the structure of the ESD protection device manufactured by the manufacturing method of the ESD protection device of this invention. It is a top view which shows the structure of the ESD protection device manufactured by the manufacturing method of the ESD protection device of this invention. It is a figure explaining the manufacturing method of the ESD protection device of this invention, and is a figure which shows the process of apply | coating a sealing layer paste to a 1st ceramic green sheet, and forming an unbaking sealing layer. It is a figure explaining the manufacturing method of the ESD protection device of this invention, and is a figure which shows the process of apply | coating a discharge auxiliary electrode paste on a non-baking sealing layer, and forming a non-baking discharge auxiliary electrode. It is a figure explaining the manufacturing method of the ESD protection device of this invention, and is a figure which shows the process of apply | coating a counter electrode paste and forming the unfired one side counter electrode and the other side counter electrode.

  Hereinafter, the features of the present invention will be described in more detail with reference to examples of the present invention.

[ Configuration of ESD protection device ]
FIG. 1 is a cross-sectional view schematically showing the structure of an ESD protection device manufactured by the method for manufacturing an ESD protection device of the present invention , and FIG. 2 is a plan view .

  As shown in FIGS. 1 and 2, the ESD protection device includes a ceramic base material 1 containing a glass component, a one-side counter electrode 2 a formed on the surface of the ceramic base material 1, and the other ends facing each other. A counter electrode 2 composed of a side counter electrode 2b, a discharge auxiliary electrode 3 formed in contact with a part of the one side counter electrode 2a and the other side counter electrode 2b and extending from the one side counter electrode 2a to the other side counter electrode 2b; The external electrode 5a for electrical connection with the outside, which is disposed at both ends of the ceramic substrate 1 so as to be electrically connected to the one-side counter electrode 2a and the other-side counter electrode 2b constituting the counter electrode 2. , 5b.

The discharge auxiliary electrode 3 includes metal particles and a ceramic component, and is configured to relieve oversintering of the discharge auxiliary electrode 3 and suppress the occurrence of short-circuit failure due to oversintering.
As the metal particles, it is possible to use copper powder, or preferably copper powder whose surface is coated with an inorganic oxide or a ceramic component. In addition, the ceramic component is not particularly limited, but as a more preferable ceramic component, the ceramic component includes a constituent material of the ceramic base (in this case, Ba-Si-Al system), or includes a semiconductor component such as SiC. The thing etc. are illustrated.

In this ESD protection device, a seal layer 11 is disposed between the discharge auxiliary electrode 3 and the ceramic substrate 1.
The seal layer 11 is a porous layer made of ceramic particles such as alumina, for example, and absorbs and holds the glass component contained in the ceramic base material 1 and the glass component generated in the ceramic base material 1 in the firing process ( Trap) to suppress and prevent the glass component from flowing into the discharge auxiliary electrode 3 and to suppress the occurrence of short-circuit failure due to overdischarge of the discharge auxiliary electrode portion.

In this ESD protection device , the seal layer 11 is not only between the discharge auxiliary electrode 3 and the ceramic substrate 1 but also between the connection portion between the counter electrode 2 and the discharge auxiliary electrode 3 and the ceramic substrate 1. Also, the glass component is arranged in a wide range so as to intervene, and the penetration of the glass component into the connecting portion is also suppressed and prevented.

  Below, the manufacturing method of the ESD protection device which has the above structures is demonstrated.

[Manufacture of ESD protection devices]
(1) Production of Ceramic Green Sheet As a ceramic material that becomes the material of the ceramic substrate 1, a material containing Ba, Al, and Si as main components is prepared.
And each material is prepared so that it may become a predetermined composition, and it calcines at 800-1000 degreeC. The obtained calcined powder is pulverized with a zirconia ball mill for 12 hours to obtain a ceramic powder.
To this ceramic powder, an organic solvent such as toluene and echinene is added and mixed, and then a binder and a plasticizer are further added and mixed to prepare a slurry.
This slurry was molded by a doctor blade method to produce a ceramic green sheet having a thickness of 50 μm.

(2) Preparation of counter electrode paste Further, as a counter electrode paste for forming the pair of counter electrodes 2a and 2b, a binder resin composed of 80% by weight of Cu powder having an average particle diameter of about 2 μm and ethyl cellulose is prepared. A counter electrode paste was prepared by adding a solvent and stirring and mixing with three rolls. The average particle size of the Cu powder refers to the center particle size (D50) determined from the particle size distribution measurement using Microtrac.

(3) Preparation of discharge auxiliary electrode paste Further, as discharge auxiliary electrode paste for forming discharge auxiliary electrode 3, Cu powder having an average particle diameter of about 3 μm whose surface is coated with 5% by weight of aluminum oxide, and average particle A discharge auxiliary electrode paste was prepared by blending silicon carbide powder having a diameter of about 0.5 μm and an organic vehicle composed of ethyl cellulose and terpineol, and stirring and mixing with three rolls. In addition, the mixing ratio of Cu powder and silicon carbide powder was adjusted to be 80/20 by volume ratio.

(4) Production of Seal Layer Paste Used to Form Seal Layer In this example, a plurality of types of pastes containing inorganic oxides and organic vehicles were prepared as the seal layer paste.

  In the present invention, the seal layer paste is a main constituent material, and the difference ΔB (= B1−B2) between the basicity B1 and the basicity B2 of the amorphous part of the ceramic base material is 1.4 or less. In this example, inorganic oxides M1 to M10 were used as the main component (seal layer main component) of the seal layer paste as shown in Table 1.

  As the organic vehicle, an organic vehicle OV1 prepared by mixing the resins P1 and P2 shown in Table 2 and a solvent (terpineol) at a ratio shown in Table 3 was used.

However, there are no particular restrictions on the type of the main component of the seal layer, its manufacturing method, and the like. For example, the characteristics were evaluated by changing the particle diameter of M3 (Al ₂ O ₃ ) in Table 1 in the range of D50 = 0.2 to 2.5 μm, but it was confirmed that there was no effect on the characteristics. In addition, it has been confirmed that there is no influence on the characteristics even in the evaluation using M3 having a different manufacturing method. In this embodiment, the main component of the seal layer is D50 = 0.4 to 0.6 μm.

<About basicity B (B1, B2)>
The basicity of the oxide melt is determined by calculating the average oxygen ion activity (conceptual basicity) calculated from the composition of the target system and the response of external stimuli such as chemical reactions (oxidation / reduction potential). Measurement, optical spectrum measurement, etc.) can be roughly divided into oxygen ion activities (working point basicity) obtained.

It is desirable to use conceptual basicity when used as a study or composition parameter for the nature and structure of oxide melts. On the other hand, it is more appropriate to sort out various phenomena related to oxide melt by the basic point of action. The basicity in the present application is the former conceptual basicity.
That is, the bonding force between M _i -O oxide (inorganic oxide) M _i O can be represented by the attraction between cations and the oxygen ions, represented by the following formula (1).

A _i = Z _i · Zo ²⁻ / (r _i + ro ²⁻ ) ² = 2Z _i / (r _i +1.4) ² (1)
A _i : attractive force between cation and oxygen ion,
Z _i : i-component cation valence,
r _i : i-component cation radius (Å),

Since the oxygen donating ability of the single component oxide M _i O is given by the reciprocal of A _i , the following equation (2) is established. B _i ⁰ ≡1 / A _i (2)
Here, the B _i ⁰ value obtained is indexed in order to handle the oxygen donating ability intentionally and quantitatively.

By substituting the B _i ⁰ value obtained by the above equation (2) into the following equation (3) and recalculating, the basicity of all oxides can be handled quantitatively.
B _i = (B _i ⁰ −B _SiO2 ⁰ ) / (B _CaO ⁰ −B _SiO2 ⁰ ) (3)
Note that during indexing, B _i value 1.000 (B _i ⁰ = 1.43) of CaO, defines a Bi value of SiO ₂ 0.000 and (B _i ⁰ = 0.41).

  Each inorganic oxide M1 to M10 shown in Table 1 and organic vehicle OV1 having the composition shown in Table 3 were prepared in the proportions shown in Table 3, and kneaded and dispersed by a three-roll mill or the like. Seal layer pastes P1 to P10 as shown in FIG.

(5) Printing each paste First, as shown in FIG. 3, a seal layer paste is applied to the first ceramic green sheet 101 to form an unfired seal layer 111.

  Then, as shown in FIG. 4, the unfired auxiliary discharge electrode 103 is formed by printing the auxiliary discharge electrode paste on the unfired seal layer 111 by a screen printing method so as to have a predetermined pattern.

Further, as shown in FIG. 5, the counter electrode paste is applied to form the unfired one-side counter electrode 102a and the unfired other-side counter electrode 102b that become the counter electrode 2 (see FIGS. 1 and 2) after firing. To do. As a result, a gap portion 110 corresponding to the discharge gap portion 10 (FIGS. 1 and 2) is formed between the mutually facing tip portions of the unfired one-side counter electrode 102a and the other-side counter electrode 102b.
In this example, the width W of the one-side counter electrode 2a and the other-side counter electrode 2b was set to 100 μm and the dimension G of the discharge gap 10 was set to 30 μm at the stage after firing.
In addition, each paste including a seal layer paste may be directly applied on an application target, or may be applied by other methods such as a transfer method.

  Further, the order of applying each paste, the specific pattern, and the like are not limited to the above example. However, it is necessary to install the counter electrode and the discharge auxiliary electrode so as to be always adjacent to each other. Further, the seal layer needs to have a structure arranged between the ceramic constituting the ceramic substrate and the electrode.

(6) Lamination and pressure bonding As described above, the paste is applied to the non-printing surface side of the first ceramic green sheet to which the paste is applied in the order of the sealing layer paste, the discharge auxiliary electrode paste, and the counter electrode paste. A plurality of second ceramic green sheets that were not laminated were laminated and pressed to form a laminate. Here, the laminate was formed so that the thickness after firing was 0.3 mm.

(7) Firing and formation of external electrode After the obtained laminate was cut to a predetermined size, the maximum temperature was 980 to 1000 ° C. in a firing furnace controlled with N ₂ / H ₂ / H ₂ O. Baked under conditions. Thereafter, an external electrode paste was applied to both ends of the baked chip (sample), and further baked in a firing furnace under controlled atmosphere, thereby obtaining an ESD protection device having a structure as shown in FIGS.

In this example, in order to evaluate the characteristics, the sealing layer pastes P1 to P10 shown in Table 4 were used as the sealing layer paste, and the ESD protection device provided with the sealing layer (samples Nos. 1 to 10 in Table 5). ) Was produced.
For comparison, an ESD protection device (sample No. 11 in Table 5) without a seal layer was produced.
Although not described in this embodiment, a protective film may be formed on the discharge gap of the fired ESD protection device for the purpose of improving the weather resistance. The material of the protective film is not particularly limited. For example, mention may be made of oxide powders such as alumina and silica and thermosetting resins such as thermosetting epoxy resins and thermosetting silicone resins. Can do.

[Characteristic evaluation]
Next, each characteristic was investigated by the following method about each ESD protection device (sample) produced as mentioned above.

(1) Thickness of reaction layer After cutting the sample along the thickness direction and polishing the cut surface, the interface between the seal layer and the ceramic substrate was observed with SEM and WDX, and formed on the interface. The thickness of the reaction layer was examined.

(2) Short-circuit characteristics A voltage was applied to each sample under two conditions of 8 kV x 50 shots and 20 kV x 10 shots. For samples with logIR> 6Ω, the short-circuit characteristics were evaluated as good (◯), and voltage was continuously applied. The sample with logIR ≦ 6Ω even once was evaluated as having poor short characteristics (×).

(3) Vpeak and Vclamp
Based on IEC standard, IEC61000-4-2, the peak voltage value: Vpeak and the voltage value after 30 ns from the wavefront value: Vclamp were measured by 8 kV contact discharge. The number of times of application was 20 times for each sample.
A sample with Vpeak_max ≦ 900V was evaluated as good (◯), and a sample with Vclamp_max ≦ 100V was evaluated as good (◯).

(4) Repetitive characteristics Short: 8 kV × 100 shots Vclamp: A load of 8 kV × 1000 shots was applied, and samples with all measurement results of log IR> 6 and Vclamp_max ≦ 100 V were evaluated as having good repetitive characteristics (◯).

(5) Substrate cracking and substrate warpage The appearance of the baked product was visually observed, and the product after cross-section polishing was observed with a microscope, and a sample with no cracking was evaluated as good (O). Moreover, about the board | substrate curvature, the product was set | placed on the horizontal board and the thing in which the float did not exist in a center part or an edge part was evaluated as favorable ((circle)).
Table 6 shows the results of evaluating the characteristics as described above.

  First, regarding the thickness of the reaction layer, as shown in Table 6, in each sample Nos. 1 to 10, there is a correlation between the ΔB value (see Table 1) and the thickness of the reaction layer, and the ΔB value is It was confirmed that the reaction layer thickness tends to increase as the value increases.

In the samples of sample numbers 1 to 10 (that is, samples having ΔB of 1.4 or less), the adhesive force at the interface between the seal layer and the ceramic constituting the ceramic substrate is sufficiently secured, and the firing temperature is It was confirmed that the material can be used even when it is lower than the melting point of the material constituting the seal layer.
In addition, in the sample of the sample number 11 which does not provide the sealing layer, the reaction layer was not confirmed.

  Regarding the short-circuit characteristics, it was confirmed that the samples Nos. 1 to 10 did not cause any short-circuit defect after the initial short-circuit and the continuous ESD application, and there was no problem with the short-circuit characteristics.

On the other hand, in the case of the sample of Sample No. 11 without the seal layer, it was confirmed that the short-circuit occurrence rate increased as the inserted voltage value increased although the short-circuit failure did not occur in the evaluation at 8 kV. This is because the sample of Sample No. 11 does not have a sealing layer, so that the amount of glass components from ceramic flowing into the discharge auxiliary electrode increases and the discharge auxiliary electrode is oversintered. it is conceivable that.
When the discharge auxiliary electrode is oversintered, the Cu powders are close to each other, and the Cu powders are fused with each other when ESD is applied, so that a short circuit is likely to occur.

  Further, in any of the samples Nos. 1 to 11, necessary characteristics for Vpeak and Vclamp were obtained, and it was confirmed that a discharge phenomenon occurred quickly in the protective element when ESD was applied.

Moreover, the following knowledge was acquired regarding the repetition characteristic. In other words, it was confirmed that in each of the samples Nos. 1 to 10, the discharge capability was kept good even when the number of times of voltage application was increased.
However, in the case of the sample of Sample No. 11 not provided with the seal layer, necessary characteristics were obtained for Vpeak and Vclamp, but regarding the short circuit characteristics, a short circuit occurred during continuous application.

  As for substrate cracking and substrate warpage, as shown in Table 6, when a material containing a part of elements constituting the ceramic substrate is used for the sealing layer, or other materials shown in Table 1 are used. In any case, ΔB (difference ΔB between the basicity B1 of the main component constituting the seal layer and the basicity B2 of the amorphous part of the ceramic constituting the ceramic substrate) is 1.33 or less. In some cases, it was confirmed that no substrate cracking or substrate warping occurred. In addition, it was confirmed from the behaviors related to substrate cracking and substrate warping for other samples not shown in Table 6 that if ΔB is 1.4 or less, it is possible to form a good seal layer with no problems such as structural destruction. ing.

To summarize the results of the above examples, according to the present invention,
(a) A short circuit caused by oversintering of the discharge auxiliary electrode by trapping the glass component to enter the discharge auxiliary electrode from the ceramic substrate by the sealing layer disposed between the discharge auxiliary electrode and the ceramic substrate. The occurrence of defects can be suppressed,
(b) By forming a reaction layer containing a reaction product formed by a reaction between the constituent material of the seal layer and the constituent material of the ceramic base material at the interface between the seal layer and the ceramic base material, Adhesion between ceramic substrates is ensured and reliability is improved.
(c) Design so that the difference ΔB (= B1−B2) between the basicity B1 of the main constituent material of the seal layer and the basicity B2 of the amorphous part constituting the ceramic substrate is 1.4 or less. As a result, it was confirmed that an excess of the reaction between the seal layer and the ceramic substrate was suppressed, and as a result, an ESD protection device having a specific effect such as suppression of oversintering of the discharge auxiliary electrode was obtained.

  In addition, since the ESD protection device obtained by the present invention has stable characteristics and does not easily deteriorate even when static electricity is repeatedly applied, it can protect various devices and devices including semiconductor devices. Therefore, it can be widely applied to the field of ESD protection devices used for this purpose.

  In addition, this invention is not limited to the said Example, A sealing layer, a counter electrode, the constituent material of a discharge auxiliary electrode, a specific shape, a formation method, the composition of the ceramic containing the glass which comprises a ceramic base material, etc. However, various applications and modifications can be made within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Ceramic base material 2 Counter electrode 2a The one side counter electrode which comprises a counter electrode 2b The other side counter electrode which comprises a counter electrode 3 Discharge auxiliary electrode 5a, 5b External electrode 10 Discharge gap part 11 Seal layer 101 1st ceramic green sheet 102a Unsintered one side counter electrode 102b Unsintered other side counter electrode 103 Unsintered discharge auxiliary electrode 110 Gap part 111 Unsintered seal layer W Width of counter electrode G Dimension of discharge gap part

Claims (1)

Printing a seal layer paste on one main surface of the first ceramic green sheet to form an unfired seal layer;
Printing a discharge auxiliary electrode paste so as to cover at least a part of the sealing layer to form an unfired discharge auxiliary electrode;
A counter electrode paste is printed on one main surface of the first ceramic green sheet, each covering a part of the discharge auxiliary electrode, and one side counter electrode disposed at a distance from each other; Forming an unfired counter electrode comprising the other counter electrode;
A step of laminating a second ceramic green sheet on the other main surface of the first ceramic green sheet to form an unfired laminate;
And firing the laminate.
At the interface between the sealing layer and the first ceramic green sheet, a reaction layer containing a reaction product generated by a reaction between the constituent material of the sealing layer and the constituent material of the first ceramic green sheet is formed. And
The difference ΔB (= B1−B2) between the basicity B1 of the main constituent material of the sealing layer and the basicity B2 of the amorphous part constituting the first ceramic green sheet is 1.33 or less. A method for manufacturing an ESD protection device.

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