Overvoltage protection element

Abstract

An overvoltage protection element comprises a substrate, a transformation material and an electrode group. A groove is formed in the surface of the substrate, and the transformation material is contained in the groove. The transformation material comprises an insulating metal material, a perovskite compound and a silicon-containing resin. The perovskite compound is selected from a group consisting of calcium titanate, strontium titanate, barium titanate and a combination thereof. And the volume percentage of the perovskite compound is 0.5%-4.5% by taking the volume of the variable-pressure material as 100%. The electrode group comprises a first electrode and a second electrode which are respectively connected with two ends of the transformation material.

Description

Technical Field

[0001] This invention relates to an overvoltage protection element, and more specifically, to an overvoltage protection element that is resistant to high voltage and has good durability. Background Technology

[0002] Integrated circuits (ICs) accept external power supplies and input signals to be processed, and output processed signals. It is important to note that the input terminals of an IC are directly connected to the gates of the input stage switches, making them highly susceptible to damage. When ICs are soldered onto circuit boards using manual clamping or automated equipment, the vulnerable input and output terminals can be damaged by electrostatic discharge (ESD). For example, a human body can charge itself through static electricity and then discharge through the input terminals of the IC semiconductor device.

[0003] Tools in automated assembly or testing equipment may also be charged and then discharged to the integrated circuit (IC) semiconductor device via its input terminals. As semiconductor technology continues to evolve, the linewidth of semiconductor devices is shrinking, highlighting the need for electrostatic discharge (ESD) protection mechanisms. Therefore, IC input terminals are often equipped with dedicated ESD protection components.

[0004] In recent years, to provide more comprehensive protection, the industry has urgently needed ESD protection components that can withstand higher voltages. As disclosed in US Patent No. 10,181,718, an internal cavity is designed within the ESD protection component to house the transformer material, thereby maintaining the structural integrity of the transformer material and improving the voltage withstand characteristics of the ESD protection component. However, this design requires reserving a certain amount of space to house the transformer material, which results in a relatively large overall size of the ESD protection component, failing to meet the current demand for miniaturization.

[0005] If the cavity of the ESD protection element is removed or its size is reduced by other means, various electrical defects are easily exacerbated as the size of the ESD protection element decreases. In addition, even if efforts are made to improve the physicochemical properties of the transformer material itself, it is often difficult to achieve significant breakthroughs due to the amplification of defects caused by the excessively small size of the element.

[0006] Therefore, there is an urgent need to develop an ESD protection component that is resistant to high voltage and has good durability. Summary of the Invention

[0007] This invention provides an overvoltage protection element comprising a substrate, a transformer material, and an electrode assembly. The substrate has a surface and grooves formed on the surface. The transformer material is housed in the grooves and comprises an insulating metal material, a perovskite compound, and a silicone resin. The perovskite compound is selected from the group consisting of calcium titanate, strontium titanate, barium titanate, and combinations thereof. The perovskite compound occupies 0.5% to 4.5% of the volume of the transformer material (100%). The electrode assembly includes a first electrode and a second electrode respectively connected to both ends of the transformer material.

[0008] According to one embodiment of the present invention, the perovskite compound is strontium titanate, and its volume percentage is 1% to 4%.

[0009] According to one embodiment of the present invention, the volume percentage of silicone resin is 51% to 55% based on the volume of the transformer material as 100%.

[0010] According to one embodiment of the present invention, the silicone-containing resin is selected from the group consisting of silicone, polydimethylsiloxane, polyethylpropylsiloxane, polypropylbutylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane, and combinations thereof.

[0011] According to one embodiment of the present invention, the volume percentage of the insulating metal material is 42% to 46.5% based on the volume of the transformer material (100%). The insulating metal material is composed of a plurality of core metal particles, and the surface of each core metal particle is covered by an insulating layer.

[0012] According to one embodiment of the present invention, the particle size of the insulating metal material is between 0.1 μm and 10 μm.

[0013] According to one embodiment of the present invention, these core metal particles comprise iron, gold, silver, copper, nickel, tin, platinum, zinc, metal carbides, or combinations thereof.

[0014] According to one embodiment of the present invention, the insulating layer comprises iron oxide, zirconium dioxide, aluminum oxide, hafnium dioxide, titanium dioxide, manganese monoxide, or silicon dioxide.

[0015] According to one embodiment of the present invention, the transformer material has a specific width parallel to the surface and a specific height perpendicular to the surface, wherein the width is between 36 μm and 48 μm and the height is between 55 μm and 65 μm.

[0016] According to one embodiment of the present invention, the transformer material is attached to the surface of the substrate and extends a certain distance, such that the width of the transformer material inside the groove is smaller than the width of the transformer material outside the groove.

[0017] According to one embodiment of the present invention, a first electrode has a first extension and a second electrode has a second extension. The first extension is connected to a transformer material along the surface of the substrate in the direction toward the second electrode, while the second extension is connected to the transformer material along the surface of the substrate in the direction toward the first electrode.

[0018] According to one embodiment of the present invention, it further includes a protective layer covering the first extension, the transformer material, and the second extension.

[0019] According to one embodiment of the present invention, the protective layer comprises bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, or a combination thereof.

[0020] According to one embodiment of the present invention, the glass transition temperature of the protective layer is greater than 140°C.

[0021] According to one embodiment of the present invention, the glass transition temperature of the protective layer is between 150°C and 165°C.

[0022] According to one embodiment of the present invention, the coefficient of thermal expansion α1 of the protective layer is between 25 ppm / ℃ and 35 ppm / ℃, while the coefficient of thermal expansion α2 of the protective layer is between 135 ppm / ℃ and 145 ppm / ℃.

[0023] According to one embodiment of the present invention, the overvoltage protection element has a withstand voltage of 8kV or more, thereby enabling the overvoltage protection element to withstand 1000 cycles of 8kV voltage application without burning out.

[0024] According to one embodiment of the present invention, the overvoltage protection element has a withstand voltage of 30kV or more, thereby enabling the overvoltage protection element to withstand 100 cycles of 30kV voltage application without burning out.

[0025] According to one embodiment of the present invention, the maximum leakage current of the overvoltage protection element is 0.5 nA or less. Attached Figure Description

[0026] Figure 1a and Figure 1b Showing a top view of the overvoltage protection element of the present invention;

[0027] Figure 2 show Figure 1b A cross-sectional view of the overvoltage protection element along line AA;

[0028] Figure 3 show Figure 2 A partial enlarged view of the overvoltage protection element; and

[0029] Figure 4 show Figure 2 A diagram showing the local variations of the overvoltage protection element.

[0030] The reference numerals in the attached figures are explained as follows:

[0031] 100 Overvoltage Protection Component

[0032] 10 substrates

[0033] 20 Transformer Materials

[0034] 30a First Electrode

[0035] 30b First Extension

[0036] 30c First Connector

[0037] 30d third electrode

[0038] 40a Second Electrode

[0039] 40b Second Extension

[0040] 40c Second Connector

[0041] 40d fourth electrode

[0042] C protective layer

[0043] H height

[0044] L distance

[0045] R groove

[0046] S1 upper surface

[0047] S2 lower surface

[0048] W width Detailed Implementation

[0049] To make the above and other technical contents, features and advantages of the present invention more apparent and understandable, relevant embodiments are provided below, and detailed descriptions are given in conjunction with the accompanying drawings.

[0050] Please refer to Figure 1a and Figure 1b The image shows a top view of the overvoltage protection element 100 of the present invention. Figure 1a and Figure 1b The difference lies in the protective layer C. To better illustrate the component configuration beneath the protective layer C, Figure 1a Protective layer C is not included. (e.g.) Figure 1a As shown, the overvoltage protection element 100 includes a substrate 10, a transformer material 20, and an electrode assembly. The substrate 10 has an upper surface S1 and a groove R formed on the upper surface S1 (see reference). Figure 2The transformer material 20 is housed in the groove R. The electrode assembly includes a first electrode 30a and a second electrode 40a disposed opposite each other at both ends of the substrate 10. The first electrode 30a has a first extension 30b, and the second electrode 40a has a second extension 40b. The first extension 30b is connected to the transformer material 20 along the upper surface S1 (i.e., along the x-axis) of the substrate 10 toward the second electrode 40a, and the second extension 40b is connected to the transformer material 20 along the upper surface S1 (i.e., along the x-axis) of the substrate 10 toward the first electrode 30a. Thus, the first electrode 30a and the second electrode 40a are connected to the left and right ends of the transformer material 20 respectively through the first extension 30b and the second extension 40b. The transformer material 20 has high resistance and does not conduct electricity under normal conditions. When electrostatic discharge occurs, the high voltage generated by the electrostatic discharge breaks down the transformer material 20, making it electrically conductive, thereby instantaneously reducing the high voltage to a low voltage. The voltage required to break down the transformer material 20 can also be called the trigger voltage of the overvoltage protection element 100.

[0051] Furthermore, the transformer material 20 of the present invention comprises an insulating metal material, a perovskite compound, and a silicone resin.

[0052] The insulating metal material is composed of multiple core metal particles, each of which is covered by an insulating layer. These core metal particles can be iron, gold, silver, copper, nickel, tin, platinum, zinc, metal carbides, or combinations thereof, while the insulating layer can be iron oxide, zirconium dioxide, aluminum oxide, hafnium dioxide, titanium dioxide, manganese monoxide, or silicon dioxide. Simply put, the insulating metal material is conductive particles that have undergone insulation treatment. For example, through a coating process, multiple iron particles can be coated onto the insulating material to form iron powder with high surface resistance. This design allows for an extremely short trigger time for the transformer material 20, less than 1 nanosecond (ns), meeting the ESD protection requirements of electronic product inputs. In one embodiment, the insulating metal material occupies 42% to 46.5% of the volume of the transformer material 20, for example, 42%, 42.5%, 43%, 43.5%, 44%, 44.5%, 45%, 45.5%, or 46%. If the volume percentage of the insulating metal material is less than 42%, the triggering time will be too long. If the volume percentage of the insulating metal material is greater than 46.5%, unexpected electrical conduction may occur. This is because an excessively large proportion of the insulating metal material will cause it to be over-compacted, resulting in the core metal particles being too close together, which greatly increases the probability of electrical conduction.

[0053] It should be noted that the present invention additionally adds fillers containing compounds having a perovskite structure (hereinafter referred to as perovskite compounds). Perovskite compounds are selected from the group consisting of calcium titanate, strontium titanate, barium titanate, and combinations thereof. The present invention observes that when the proportion of perovskite compounds is controlled within a specific range, the transformer material 20 can withstand higher voltage surges without burning out. For example, in one embodiment, the overvoltage protection element 100 has a withstand voltage of 8 kV or higher, thereby allowing the overvoltage protection element 100 to withstand 1000 cycles of 8 kV voltage application without burning out. In another embodiment, the overvoltage protection element 100 has a withstand voltage of 30 kV or higher, thereby allowing the overvoltage protection element 100 to withstand 100 cycles of 30 kV voltage application without burning out. A single cycle involves applying a specific voltage to the overvoltage protection element 100 for 10 seconds and then turning it off for 60 seconds. Based on the volume of transformer material 20 as 100%, the volume percentage of the perovskite compound is 0.5% to 4.5%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, or 4%. Furthermore, the present invention unexpectedly discovered that when strontium titanate is selected as the perovskite compound, the leakage current problem is significantly improved. In one embodiment, when strontium titanate is selected as the perovskite compound, the maximum leakage current of the overvoltage protection element 100 is less than 0.5 nA.

[0054] It should also be mentioned that the overvoltage protection element 100 of the present invention is a polymer-type ESD protection element (i.e., a pESD protection element). The transformer material 20 uses a silicone resin as a base material, and the aforementioned insulating metal material and perovskite compound are uniformly dispersed therein. The silicone resin can be selected from the group consisting of silicone, polydimethylsiloxane, polyethylpropylsiloxane, polypropylbutylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane, and combinations thereof. In one embodiment, the volume percentage of the silicone resin, based on 100% of the transformer material volume, is 51% to 55%, for example, 51%, 52%, 53%, 54%, or 55%.

[0055] Please continue to refer to Figure 2 ,show Figure 1b The overvoltage protection element 100 is shown in a cross-sectional view along line AA. In this figure, the substrate 10 further includes a lower surface S2. The upper surface S1 is disposed opposite to the lower surface S2. The electrode group further includes a third electrode 30d and a fourth electrode 40d, which are respectively disposed at both ends of the lower surface S2 of the substrate 10. In addition, the sidewalls of the substrate 10 have grooves (such as... Figure 1bThe structure (which presents a semi-circular outline when viewed from above) can be used to accommodate the first connector 30c and the second connector 40c. Thus, the first electrode 30a and the third electrode 30d are electrically connected through the first connector 30c, while the second electrode 40a and the fourth electrode 40d are electrically connected through the second connector 40c. As mentioned above, the overvoltage protection element 100 also includes a protective layer C, which covers the first extension 30b, the transformer material 20, and the second extension 40b, thereby avoiding unnecessary electrical connections and protecting the transformer material 20 from interference from external environmental factors. The protective layer C contains epoxy resin, which may be bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, or a combination thereof. Furthermore, the glass transition temperature (Tg) of the protective layer C is greater than 140°C, preferably between 150°C and 165°C. Furthermore, the coefficient of thermal expansion of the protective layer C, α1 (i.e., α1-CTE), is between 25 ppm / ℃ and 35 ppm / ℃, while the coefficient of thermal expansion of the protective layer C, α2 (i.e., α2-CTE), is between 135 ppm / ℃ and 145 ppm / ℃. α1-CTE is defined as the coefficient of thermal expansion of an object at temperatures below Tg, while α2-CTE is defined as the coefficient of thermal expansion of an object at temperatures above Tg.

[0056] Please continue to refer to Figure 3 and Figure 4 , respectively Figure 2 The overvoltage protection element 100 is shown in a partially enlarged view and a partially varied view within the dashed box. This invention observes that, in the presence of the groove R, the transformer material 20 must maintain a certain cross-sectional area to achieve stable high-voltage resistance. More specifically, in Figure 3 In this embodiment, the transformer material 20 has a specific width W parallel to the upper surface S1 of the substrate 10 and a specific height H perpendicular to the upper surface S1 of the substrate 10. The width W is between 36 μm and 48 μm, and the height H is between 55 μm and 65 μm. Furthermore, to increase the contact area of ​​the transformer material 20, it can also be attached to the substrate 10 and creep a certain distance. For example, in... Figure 4 In this process, the transformer material 20 is attached to the upper surface S1 of the substrate 10 and extends a distance L. Thus, the width of the transformer material 20 inside the groove R is smaller than the width W of the transformer material 20 outside the groove R, forming a cross-sectional profile that is wider at the top and narrower at the bottom.

[0057] To illustrate the technical content of this invention more specifically, Tables 1 to 5 below provide further discussion using actual verification data. Subsequent verification mainly involves comparing the differences in transformer materials and protective layers.

[0058] Table 1. Formulation of transformer materials (vol%)

[0059] Group Insulated iron powder silicone <![CDATA[SrTiO3]]> <![CDATA[BaTiO3]]> <![CDATA[CaTiO3]]> AlN ZnO <![CDATA[Al2O3]]> E1 42.0 54.0 4.0 E2 43.5 54.0 2.5 E3 45.0 53.0 2.0 E4 44.5 54.0 1.5 E5 44.0 55.0 1.0 E6 46.5 51.0 2.5 E7 46.5 51.0 2.5 C1 46.5 51.0 2.5 C2 46.5 51.0 2.5 C3 48.0 51.0 1 C4 48.0 51.0 1

[0060] Table 1 shows the formulation composition of the transformer materials for each example (E1 to E7) and comparative example (C1 to C4) by volume percentage. The first column shows the groups from top to bottom, namely E1 to C4. The first column shows the materials in the transformer material from left to right, namely, insulating iron powder, silicone rubber, strontium titanate (SrTiO3), barium titanate (BaTiO3), calcium titanate (CaTiO3), aluminum nitride (AlN), zinc oxide (ZnO), and aluminum oxide (Al2O3). The insulating iron powder is the aforementioned insulating metal material. Furthermore, to achieve optimal density of the insulating iron powder in the groove R, the average particle size of the iron powder is less than 10 μm. As can be seen from Table 1, the transformer material is mainly composed of an insulating conductor (i.e., insulating iron powder), a polymer (i.e., silicone rubber), and fillers (such as SrTiO3, BaTiO3, CaTiO3, AlN, ZnO, or Al2O3), while the difference between the examples and the comparative examples lies in the type of filler. The fillers used in Examples E1 to E7 were perovskite compounds, while Comparative Examples C1 to C4 used other conventionally used fillers. It should be noted that the present invention unexpectedly discovered that slight variations in strontium titanate (SrTiO3) could significantly improve electrical performance; therefore, Examples E1 to E5 specifically tested different proportions of strontium titanate (SrTiO3).

[0061] The particle size of the filler in this invention is also controlled within a certain range. Before the aforementioned filler is prepared according to the composition ratio shown in Table 1, the particle size of the filler powder is measured using a Malvern Mastersizer 2000 particle size analyzer. See Table 2 below for details.

[0062] Table 2. Packing Particle Size Distribution

[0063]

[0064]

[0065] As shown in Table 2, D represents the particle size distribution, and the number in square brackets after D represents the proportion of the total number of particles. The proportion is 1, so 0.1, 0.5, and 0.9 represent 10%, 50%, and 90%, respectively. The values ​​in columns D(0.1), D(0.5), and D(0.9) are the particle sizes. For example, D(0.1) means that 10% of the particles are smaller than this value, and the same applies to D(0.5) and D(0.9). Therefore, D(0.5) is the median value of the particle size distribution, i.e., the median particle size. For example, in BaTiO3 filler, half of the particles are smaller than 8.29 μm. In SrTiO3 filler, half of the particles are smaller than 5.96 μm. In CaTiO3 filler, half of the particles are smaller than 9.15 μm. And so on. It should be noted that during the manufacturing process of transformer materials, the filler is further crushed to an average particle size of less than 10 μm using a three-roll mill to facilitate uniform dispersion within the transformer material. Therefore, traditionally, fillers with a D(0.9) close to 10 μm are typically selected for mixing to ensure that the filler maintains an extremely small size of less than 10 μm after grinding. However, this invention deliberately selects perovskite-based compound particles with a D(0.9) close to 20 μm. Even after three-roll mill processing, a small amount of incompletely ground large particles (i.e., particles with a size of 10 μm to 20 μm) will remain. Thus, these trace amounts of large particles can significantly improve the overall voltage withstand capability of the transformer material.

[0066] Table 3. Protective Layer

[0067]

[0068] The overvoltage protection element in the embodiments and comparative examples is fabricated as follows: Figure 1a After the structure is completed, a protective layer will be applied to form a structure like this. Figure 1bThe protective layer is made of epoxy resin, with three types available. EI-4500 refers to the EPORITE series EI-4500 epoxy resin from Daige Chemical Industry; S-300 and R-500 refer to the S-300 and R-500 series epoxy resins from Yong Sheng Tai Technology Co., Ltd. Compared to S-300 and R-500, EI-4500 has a higher viscosity and glass transition temperature, resulting in a more stable structure at high temperatures. Furthermore, EI-4500 has the highest coefficient of thermal expansion α1 and the lowest coefficient of thermal expansion α2. This means that below the glass transition temperature, EI-4500 has the highest coefficient of thermal expansion, while above the glass transition temperature, it has the lowest. Examples E1 to E7 use EI-4500 epoxy resin as their protective layer. Comparative Examples C1 to C3 used S-300 epoxy resin as their protective layer, while Comparative Example C4 used R-500 epoxy resin as its protective layer.

[0069] The transformer material in this embodiment is manufactured in the same manner as in the comparative example. First, insulating iron powder, silicone, and filler are mixed and stirred for one hour to form a slurry. Next, the slurry is processed three times using a three-roll mill, and the particle size is confirmed to be less than 10 μm using a particle size analyzer before acceptance. The slurry is then printed into groove R and subsequently cured at 170°C to form the transformer material. A protective layer is then applied over the transformer material and cured at 170°C as well. Finally, the element is irradiated with a light dose of 100 kgy.

[0070] Table 4. Electrical Characteristics 1

[0071] Group Trigger voltage (V) Withstand pressure test 1 Pressure resistance test 2 Pressure resistance test 3 E1 467 pass pass pass E2 459 pass pass pass E3 421 pass pass pass E4 433 pass pass pass E5 441 pass pass pass E6 449 pass pass pass E7 423 pass pass pass C1 368 pass Not passed Not passed C2 390 pass Not passed Not passed C3 624 pass Not passed Not passed C4 639 pass Not passed Not passed

[0072] Table 4 above shows the trigger voltage and withstand voltage capability of each group.

[0073] The definition of trigger voltage has been described above, so I will not elaborate further here.

[0074] The withstand voltage test involves applying a specific voltage for 10 seconds, followed by a 60-second shutdown cycle.

[0075] The applied voltage for the withstand voltage test is 8kV, and the number of cycles is 1000.

[0076] The applied voltage for the withstand voltage test 2 is 30kV, and the number of cycles is 50.

[0077] The applied voltage for withstand voltage test three is 30kV, and the number of cycles is 100.

[0078] Embodiments E1 to E7 of the present invention have stable triggering conditions, all capable of starting between 400V and 500V. In contrast, the triggering voltages of comparative examples C1 to C4 are more variable, ranging from 300V to 700V. Furthermore, embodiments E1 to E7 of the present invention can withstand extremely high voltage (30kV) surges without burning out after triggering. In contrast, comparative examples C1 to C4 only pass withstand voltage test one without burning out, but burn out in withstand voltage tests two and three. Clearly, the structural design and transformer material formulation of the present invention can significantly improve the withstand voltage capability of overvoltage protection components.

[0079] Table 5. Electrical Characteristics II

[0080]

[0081]

[0082] As shown in Table 5, this experiment further compares the differences in leakage current among the groups.

[0083] "Leakage current after low voltage triggering" refers to the maximum leakage current of the overvoltage protection element after 50 cycles at 2kV. "Leakage current after withstand voltage test two" refers to the maximum leakage current of the overvoltage protection element after the aforementioned withstand voltage test two. "Leakage current after withstand voltage test three" refers to the maximum leakage current of the overvoltage protection element after the aforementioned withstand voltage test three. As shown in Table 5, under relatively low voltage triggering conditions, all embodiments and all comparative examples did not burn out, while the leakage current of the comparative examples was generally much larger, even reaching 257nA. It can also be noted that the leakage current of embodiments E1 to E5 is less than 1nA, far less than that of embodiments E6 and E7. Furthermore, the aforementioned differences become more significant with increasing applied voltage. For example, after withstand voltage test three, the leakage current of embodiments E1 to E5 is 0.09nA to 0.5nA, while the leakage current of embodiments E6 to E7 is 365nA to 650nA, a difference of hundreds to thousands of times. As mentioned above, the perovskite compound used in Examples E1 to E5 is strontium titanate (SrTiO3), while the perovskite compounds used in Examples E6 and E7 are barium titanate (BaTiO3) and calcium titanate (CaTiO3), respectively. In summary, this invention not only improves the voltage withstand capability and durability of overvoltage protection components through perovskite compounds, but also discovers that specific perovskite compounds (i.e., SrTiO3) can further improve leakage current issues.

[0084] The technical content and features of this invention have been disclosed above. However, those skilled in the art may still make various substitutions and modifications without departing from the concept of this invention based on the teachings and disclosures of this invention. Therefore, the scope of protection of this invention should not be limited to what is disclosed in the embodiments, but should include various substitutions and modifications without departing from this invention, and is covered by the following claims.

Claims

1. An overvoltage protection element, comprising: A substrate having a surface and a groove formed on the surface; A transformer material, disposed in the groove, comprises an insulating metal material, a perovskite compound, and a silicone resin, wherein: The perovskite compounds are selected from the group consisting of calcium titanate, strontium titanate, barium titanate, and combinations thereof; and Based on the volume of the transformer material being 100%, the perovskite compound accounts for a volume percentage of 0.5% to 4.5%; and An electrode assembly includes a first electrode and a second electrode, which are respectively connected to the two ends of the transformer material.

2. The overvoltage protection element according to claim 1, wherein the perovskite compound is strontium titanate, and its volume percentage is 1% to 4%.

3. The overvoltage protection element according to claim 2, wherein the volume percentage of the silicone resin is 51% to 55% based on the volume of the transformer material as 100%.

4. The overvoltage protection element according to claim 3, wherein the silicone resin is selected from the group consisting of silicone, polydimethylsiloxane, polyethylpropylsiloxane, polypropylbutylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane, and combinations thereof.

5. The overvoltage protection element according to claim 3, wherein: Based on the volume of the transformer material being 100%, the volume percentage of the insulating metal material is 42% to 46.5%. as well as The insulating metal material is composed of multiple core metal particles, and the surface of each core metal particle is covered by an insulating layer.

6. The overvoltage protection element according to claim 5, wherein the particle size of the insulating metal material is between 0.1 μm and 10 μm.

7. The overvoltage protection element according to claim 6, wherein the plurality of core metal particles comprise iron, gold, silver, copper, nickel, tin, platinum, zinc, metal carbides, or combinations thereof.

8. The overvoltage protection element according to claim 7, wherein the insulating layer comprises iron oxide, zirconium dioxide, aluminum oxide, hafnium dioxide, titanium dioxide, manganese monoxide, or silicon dioxide.

9. The overvoltage protection element according to claim 1, wherein the transformer material has a width parallel to the surface and a height perpendicular to the surface, wherein the width is between 36 μm and 48 μm, and the height is between 55 μm and 65 μm.

10. The overvoltage protection element according to claim 1, wherein the transformer material is attached to the surface and extends a distance such that the width of the transformer material within the groove is smaller than the width of the transformer material outside the groove.

11. The overvoltage protection element according to claim 1, wherein the first electrode has a first extension and the second electrode has a second extension, wherein the first extension is connected to the transformer material along the surface toward the second electrode, and the second extension is connected to the transformer material along the surface toward the first electrode.

12. The overvoltage protection element according to claim 11 further comprises a protective layer covering the first extension, the transformer material, and the second extension.

13. The overvoltage protection element according to claim 12, wherein the protective layer comprises bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, or a combination thereof.

14. The overvoltage protection element according to claim 13, wherein the glass transition temperature of the protective layer is greater than 140°C.

15. The overvoltage protection element according to claim 14, wherein the glass transition temperature of the protective layer is between 150°C and 165°C.

16. The overvoltage protection element according to claim 15, wherein the coefficient of thermal expansion α1 of the protective layer is between 25 ppm / ℃ and 35 ppm / ℃, and the coefficient of thermal expansion α2 of the protective layer is between 135 ppm / ℃ and 145 ppm / ℃.

17. The overvoltage protection element according to claim 1, wherein the overvoltage protection element has a withstand voltage of 8kV or more, thereby allowing the overvoltage protection element to withstand 1000 cycles of 8kV voltage application without burning out.

18. The overvoltage protection element according to claim 1, wherein the overvoltage protection element has a withstand voltage of 30kV or more, thereby allowing the overvoltage protection element to withstand 100 cycles of 30kV voltage application without burning out.

19. The overvoltage protection element according to claim 1, wherein the maximum leakage current of the overvoltage protection element is less than 0.5 nA.

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