CN2475102Y - Tier-type low capacitance over-voltage protective element - Google Patents

Abstract

A laminated low-capacitance overvoltage protection element, characterized in that: the laminated low-capacity overvoltage protection element is composed of a lower electrode plate made of a conductor material on a substrate, and a layer arranged on the lower electrode plate The material sensitive to voltage is composed of a layer of upper electrode plate of conductive material located on the material sensitive to voltage. The advantages are: it meets the requirements of low capacitance characteristics; it takes into account both the protection start-up trigger voltage and the clamping voltage characteristics after the protection function is exerted, and can be produced by standard thick film printing production equipment, with low equipment investment and easy mass production. Excellent performance.

Description

Composite Low Capacitance Overvoltage Protection Components

The utility model relates to an overvoltage protection element, in particular to a laminated low-capacitance overvoltage protection element.

As we all know, overvoltage will cause damage to the circuit system. Today, with the deepening of research, the amount of economic loss caused by overvoltage damage to more sophisticated system components is gradually increasing. With the use of the system Personalization and mobility, as well as the trend of high-speed and low-voltage systems, the destructive power of overvoltage is also relatively stronger. In view of this, the demand for adding overvoltage protection components in the system circuit is becoming more and more extensive and urgent.

In terms of the characteristics of overvoltage protection components, general components have the characteristics of capacitance. Compared with the high-speed development of system operating frequency, at the same time, considering the needs of lower capacitance value and faster response speed of overvoltage protection components, this type of product is currently used. Almost all components are moving in the direction of using lower capacitance values. However, while considering reducing the capacitance value of the overvoltage protection element, the protection starting trigger voltage of the protection element and the clamping voltage after the protection function is played must also be considered. If the voltage is kept lower, the impact on the protected element will be reduced. to a lower degree.

Voltage-sensitive materials Several materials have been published or used in overvoltage protection element materials. Zinc oxide is one of the main materials of varistors, which is currently the most used overvoltage protection element. In US Pat. No. 4,726,991, an element is disclosed. The structure of the element is that a conductor or semiconductor powder is coated with an insulating layer, and the thickness of the insulating layer is less than hundreds of atomic diameters (angstroms). In addition, the use of various conductive powders, semiconductor powders or non-conductive powders to be uniformly mixed with voltage sensitive materials containing binders has been published in many US patents, such as US Patent Nos. , No. 5,393,596 and No. 5,807,509 and other cases, these materials can be used as voltage-sensitive materials for overvoltage protection components, and can be used in the composite overvoltage protection component of the present invention.

Chip-type multilayer varistor components are one of the most widely used components at present, but the high capacitance value of this kind of components is also a shortcoming in its essential characteristics. Although it is possible to reduce the capacitance value by relying on structural adjustments To the extent of about 3pF, but the protection start-up trigger voltage and the clamping voltage after the protection function is exerted are also relatively increased; another commonly used overvoltage protection component is a semiconductor-type special diode component, but this kind of component can only reach 3pF about the capacitance value characteristics.

Common overvoltage protection components aimed entirely at low capacitance values are characterized by the structure and function of forming a micro-gap between the cross-sections of the electrodes at both ends of the component, and filling the gap with voltage-sensitive materials. The area is extremely small, so that the overvoltage protection element has an extremely low capacitance value, and this capacitance value is generally below 1pF. There are two types of component structures that have been disclosed at present: the first one uses a general printed circuit board (PCB) process to complete the main structure of the component, U.S. Patent No. 6,023,028 and No. 5,974,661. A substrate 100 made of an insulating plate, on which separate left and right electrode layers 111, 112 are formed, usually made of copper foil; on the left and right electrode layers 111, 112, and on the substrate 100 therebetween, used for A material layer 120 sensitive to voltage; above the material layer 120, there is a main structure protective layer 130 covering the left and right electrode layers; the other is obtained by using a standard thick film printing process, such as the US Patent Case No. 6,013,358, its structure is as shown in Figure 2, with a ceramic carrier substrate 200, on which a micro-gap cutting buffer glass material layer 220 is formed; printed conductor left and right electrode layers 231, 232 are formed on its main two sides, The left and right electrode layers are separated and covered part of the left and right electrode layers; the voltage-sensitive material layer 240 is formed on the left and right electrode layers 231, 232, and extends into the above-mentioned buffer glass material layer 220; It is the protective layer 250 of the entire main structure. This kind of overvoltage protection element manufactured by standard thick film printing process must be combined with a special micro-gap cutting process to complete the main structure of the element. The main structure and relative manufacturing process of these two components can easily meet the characteristic requirements of low capacitance value, but there are also many shortcomings, problems and manufacturing difficulties as shown in the following descriptions:

1. The low-capacitance overvoltage protection components are produced by the printed circuit board (PCB) process. Due to the inherent limitations of the printed circuit board (PCB) process, although the formation of micro-gap is quite easy, the gap distance is limited and cannot be done very well. Although the characteristics of small and low capacitance values can be met, the protection start-up trigger voltage and the clamping voltage after the protection function is exerted are also quite high, which has a bad influence on the protection function.

2. The main structure of the component is completed with the standard thick film printing process and the special micro-gap cutting process; although the standard thick film printing process can complete the laminated structure, the micro-gap cutting process can also achieve a fairly small gap size , but the special micro-gap cutting process requires special micro-gap cutting equipment, and the cost of the equipment required is high; in addition, the cutting process is very easy to form burrs on the electrode and the gap section, and the sharp discharge effect produced has a negative impact on the qualified rate of component production It has a great influence, and the speed of the cutting operation cannot be too fast, which also greatly restricts the production speed.

In view of the above-mentioned shortcomings of common low-capacitance overvoltage protection components, the main purpose of this utility model is to provide a composite low-capacitance overvoltage protection component. The voltage protection component not only meets the requirements of low capacitance characteristics, but also takes into account the possible structural design of the protection start-up trigger voltage and the clamping voltage characteristics after the protection function is exerted. By adjusting the process through structural considerations, it can be produced by standard thick film printing production equipment. Completing the main structure of overvoltage protection components with low capacitance value not only reduces equipment investment and facilitates mass production, but also enables better performance while reducing costs due to the good adjustment of related manufacturing processes.

Another main purpose of the present invention is to provide a composite low-capacitance overvoltage protection element, whose capacitance can easily reach below 1pF, which can meet the requirements of low-capacitance overvoltage protection.

Another purpose of this utility model is to provide a composite low-capacitance overvoltage protection element, which can not only meet the requirements of low capacitance value characteristics, but also protect the start-up trigger voltage and the clamping voltage characteristics after the protection function is exerted. fairly low level.

Another object of the present invention is to provide a composite low-capacitance overvoltage protection element, which has relatively low equipment investment and can be easily mass-produced at low cost and has a high pass rate and low capacitance overvoltage protection element.

The above-mentioned purpose of the utility model is achieved by the following technical solutions.

A laminated low-capacitance overvoltage protection element is characterized in that: it is a laminated low-capacity overvoltage protection element, and its structure includes a layer of lower electrode plates made of conductive materials on the substrate, and a layer of lower electrode plates arranged on the lower electrode plate The voltage-sensitive material above, and an upper electrode plate of a layer of conductive material on the voltage-sensitive material.

In addition to the above-mentioned necessary technical features, the following technical content may also be added during the specific implementation process:

Between the voltage-sensitive material on the lower electrode plate and the upper electrode plate of a conductor material on the voltage-sensitive material, there is a layer on the voltage-sensitive material to reserve a connection hole Capacitance limits the low-k material layer.

The voltage-sensitive material has a thickness of 3 μm to 150 μm.

The low dielectric constant material is glass material.

The low dielectric constant material is a polymer material.

The low dielectric constant material is a ceramic material.

The utility model has the advantages of:

1. The utility model's superimposed low-capacitance overvoltage protection element, the capacitance value of the element can be controlled by the printing superimposed area and the thickness of the voltage-sensitive material layer, which can easily meet the requirement that the capacitance value is less than 1pF.

2. The thickness of the voltage-sensitive material layer in the superimposed low-capacitance overvoltage protection element of the present invention can be adjusted by using the mold and printing parameters, so the protection start-up trigger voltage and the clamping voltage characteristics after the protection function is exerted can be adjusted. protected at a fairly low level.

3. The production of the utility model can be completed by using the standard thick film printing process. The equipment and related products have high commonality, are extremely mass-producible, and at the same time are low in cost; Mass production is easy and the qualified rate is high.

Below in conjunction with accompanying drawing and preferred embodiment the utility model is described further.

Description of drawings:

Figure 1 is a cross-sectional structure diagram of a common PCB-type low-capacitance overvoltage protection component structure;

Figure 2 is a cross-sectional structure diagram of a common micro-gap cutting, thick-film printing low-capacitance overvoltage protection component structure;

Fig. 3 is a part of the cross-sectional structure of the superimposed low-capacitance overvoltage protection element structure of the utility model

Example;

Fig. 4 is another embodiment of the cross-sectional structure of the superimposed low-capacitance overvoltage protection element structure of the utility model;

5A to 5E are plan views of a manufacturing process embodiment of the present invention;

6A to 6E are side views of the process embodiment shown in FIGS. 5A to 5E;

Fig. 7 is the response curve of the electrostatic discharge of the present utility model.

The composite low-capacitance overvoltage protection element of the present invention is shown in Figures 3 and 4.

Please refer to FIG. 3 , on the ceramic carrier substrate 300 , a separate printed conductor lower electrode layer 311 and a printed conductor upper electrode lead layer 312 are printed, and then printed on the printed conductor lower electrode layer 311 to form a pair of voltage pairs. The sensitive material layer 320 is then laminated and printed on the printed conductor upper electrode lead layer 312 and the voltage-sensitive material layer 320 to form the printed conductor upper electrode layer 340. In this way, the utility model is completed. The main structure of the overvoltage protection element can be printed with a protective layer 350 covering the main structure.

As shown in Figure 4, it is another typical main structure of the present utility model, and Figure 5 is an example of the manufacturing process of Figure 4, on the ceramic carrier substrate 300, the overvoltage protection element of the present utility model is printed and produced The printed conductor lower electrode layer 311 of the main structure and the printed conductor upper electrode lead layer 312 (as shown in FIGS. 5B and FIG. 6B ), in order to further reduce the capacitance value of the electrostatic protection element, on the voltage-sensitive material layer 320, the capacitance value is limited and the low-permittivity glass material layers 331 and 332 (such as 5C and FIG. 6C ), and the upper electrode connection hole position 335 is reserved on the voltage-sensitive material layer 320, the area of the connection hole can be adjusted according to actual needs, and the capacitance of the element can also be adjusted by the area Change and adjust, and then on the capacitance value limited low dielectric coefficient glass material layers 331 and 332, the electrode lead layer 312 on the printed conductor and the voltage-sensitive material layer 320 reserved holes, superimposed printing to produce the printed conductor. The electrode layer 340 (as shown in Figure 5C and Figure 6D) completes the main structure of the composite low-capacitance overvoltage protection element of the present invention, and then prints the protective layer 350 covering the main structure (as shown in Figure 5E and Figure 6E) .

According to the spirit of the present invention, a typical main structure is based on a ceramic carrier substrate, but in fact, in addition to ceramic materials, there are glass substrates, silicon wafers or polymer substrates (RF4) that can be used. In addition to the glass of the typical main structure, the low dielectric constant material is also available with a low dielectric constant polymer material or ceramic material.

The implementation of the structure of the present utility model, such as the detailed description of the preferred specific embodiment, is completed by the superimposed printing of the lower electrode layer of the printed conductor, the voltage-sensitive material layer and the upper electrode layer of the printed conductor. Low capacitance overvoltage protection element structure. Among them, the thickness of the voltage-sensitive material layer can be adjusted from 3 μm to 150 μm by adjusting the printing mold and parameters according to the characteristics of the voltage-sensitive material; if the printing process capacity is sufficient, this simplest structure can be produced. If the printing process capacity is slightly insufficient for the structure that meets the requirements of the capacitance value of the component, simply add a layer of capacitance-limited low-k dielectric material layer to print, and the structure that meets the requirements of the capacitance value of the component can be produced.

Fig. 7 is the reaction curve of electrostatic discharge of the present invention, and curve 1 is that the electric current of electrostatic discharge passes through the reaction curve of component, and static source is according to the standard IEC61000-4-2 that International Electron Technology Association (IEC) announces, and electrostatic voltage is 8kV wave, As shown in the figure, it can be clearly seen that the maximum passing current of the current curve shown in curve 1 is greater than 30A based on the reaction status of the laminated overvoltage protection element. As shown in the voltage curve of curve 2, the peak voltage (peak voltage) is only below 300V, that is to say, when an 8kV static electricity occurs, the element of the present invention will drop the voltage below 300V. Design, the area of the connection hole is 0.015 mm square, the material sensitive to voltage is zinc oxide material, its thickness is 50 microns, and the capacitance value of the element is approximately equal to 0.4pF.

From the above, the laminated low-capacitance overvoltage protection element of the present utility model can indeed complete its structure with a standard thick film printing process, which is completely different from the structure of common low-capacitance overvoltage protection elements, and has never seen the same stacked The structure of the integrated low-capacitance overvoltage protection element, for those who are familiar with the process technology of thick film printing elements, any slight changes made to the utility model, if they do not deviate from the spirit of the utility model, should be included in the utility model within the scope of the technical program.

Claims (6)

1. A laminated low-capacitance overvoltage protection element, characterized in that: it is a lower electrode plate made of a conductor material on the substrate, a layer of voltage-sensitive material arranged on the lower electrode plate, and A layer of upper electrode plate of conductive material on top of voltage sensitive material. 2. The laminated low-capacitance overvoltage protection element according to claim 1, characterized in that: the voltage-sensitive material on the lower electrode plate, and a layer of conductor material on the voltage-sensitive material Between the upper electrode plates, there is a layer of low dielectric constant material layer located on the voltage-sensitive material to reserve the capacitance value of the connection hole. 3. The composite low-capacitance overvoltage protection element according to claim 1 or 2, characterized in that the thickness of the voltage-sensitive material is 3 μm to 150 μm. 4. The laminated low-capacitance overvoltage protection element as claimed in claim 2, wherein the low dielectric coefficient material is glass material. 5. The laminated low-capacitance overvoltage protection element as claimed in claim 2, wherein the low dielectric constant material is a polymer material. 6. The laminated low-capacitance overvoltage protection element as claimed in claim 2, wherein the low dielectric constant material is ceramic material.

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