CN201130650Y - Surface-mount thin-film fuse structure - Google Patents

Abstract

The surface-mount thin-film fuse structure of the present invention has a fuse line structure disposed on at least one surface of an insulating substrate, wherein the fuse line structure connects a fuse link portion between two corresponding electrode portions, so that when an excessive current passes through the fuse link portion, the fuse link portion will generate a high temperature or a specific temperature to cause fusing, thereby achieving a circuit protection effect of blocking the excessive current; wherein, at least one space is arranged between the melting chain part and the insulating base material, so that a heat source generated after the melting chain part is electrified can not be dissipated through the heat conduction of the insulating base material, the melting chain part is ensured to melt by reaching a specific current or a specific temperature, and the effect of circuit protection is further ensured.

Description

Surface Mount Thin Film Fuse Structure

technical field

The utility model provides a surface-bonded thin-film fuse structure and a manufacturing method thereof, especially a circuit protection effect that can ensure that the surface-bonded thin-film fuse reaches a specific current or a specific temperature and causes fusing to block excess current. Surface mount thin film fuse structure and manufacturing method thereof.

Background technique

Press, the general electrical device will set the maximum use current. When the current used exceeds, the device may be damaged or burned. The main function of the fuse is to prevent the excess current from passing through the electronic circuit. When the excess current flows The fuse will cause it to generate high temperature and cause fusing to protect the circuit from damage. In existing electrical devices such as information, communication, and consumer electronics products, printed circuit boards (Printed Circuit Board, PCB) are mainly used to integrate electronics The components are connected together to make them function as a whole. As electrical devices become more and more complex, more and more parts are required, and the lines and parts on the printed circuit board are becoming denser and denser.

At present, the component packaging technology of printed circuit boards is mainly based on "Through Hole Technology (THT)" and "Surface Mounted Technology (SMT)", in which plug-in packaging places parts on one side of the board. And solder the pins on the other side, this kind of parts will take up a lot of space, and the printed circuit board must drill holes for each pin of the part, which will occupy the space on both sides of the printed circuit board because of the pins, Moreover, the solder joints of the pins are also relatively large; on the other hand, the surface mount package places the surface mount device (Surface Mount Device, SMD) on the printed circuit board that has been stained with glue or solder paste, and then uses a certain amount of heating The technology enables components to be fixed on the surface of the printed circuit board. The biggest difference between it and the traditional plug-in package is that it does not rely on the component feet to be inserted into the drilled circuit to support the weight of the component or maintain the direction of the component. In addition, the surface mount component and The electrodes that form the connection of the printed circuit board are located on the same side as the parts, so that the parts can be mounted on both sides of the printed circuit board at the same position. Therefore, compared with the printed circuit board of the plug-in packaging technology, the printed circuit board using the surface mount packaging technology The parts of the board can be relatively dense, which means that more functions can be placed on the same area of the printed circuit board, or the same function can be maintained with a smaller area of the printed circuit board.

Therefore, the fuse used for equipment overload current protection also has a surface mount type, as shown in Figure 1, which is a structural cross-sectional view of a surface mount type fuse that is commonly seen in the market. This surface mount type fuse is mainly in a Electrode portions 12 are provided at two corresponding positions on the bottom surface of an insulating substrate 11 (such as FR4) made of a similar printed circuit board material, and the two corresponding electrode portions 12 extend to the top surface along the outer wall surface of the insulating substrate 11, and It is only connected by a melting link part 13 mainly composed of a copper-plated film. The entire surface mount fuse is further provided with a tin layer 14 in the middle of the melting link part 13. This tin layer 14 is different from the copper of the melting link part 13. Metal, mainly when the tin layer 14 is melted due to an overcurrent load, the melting link part 13 can be turned into a tin-copper alloy, so that the melting link part 13 has a lower melting point than that of tin or copper alone, and also makes the melting link part 13 The operating temperature of the device is reduced to improve overall fuse performance. In addition, the top surface of the insulating substrate 11 is provided with a protective layer 15 made of a photoimageable material to protect the melting link 13 and the tin layer 14 on it from oxidation, and to produce a shielding effect to prevent metal melt from splashing out. .

When in use, the entire surface mount fuse uses the melting link 13 to form the circuit conduction of the two electrode parts 12. Therefore, when the excess current passes through the melting link, it will generate high temperature or a specific temperature and cause it to fuse, so as to achieve The circuit protection effect of blocking excess current; however, in reality, when the melting link 13 is energized and generates a heat source, this part of the heat source will be due to the contact between the melting link 13 and the insulating substrate 11 , and the part of the heat source is dissipated through the heat conduction of the insulating base material 11, so that when the set excess current passes through the melting link part 13, the melting link part 13 cannot reach a specific current or a specific high temperature and is fused, and thus cannot achieve blocking excess The circuit protection effect of electric current will damage or burn out the electronic circuit of the electrical device.

Utility model content

The technical problem to be solved by this utility model is to provide a surface-mounted thin-film fuse structure and its manufacture that can reliably maintain the circuit protection effect of the surface-mounted thin-film fuse when it reaches a specific current or a specific temperature to block the excess current. method.

In order to achieve the above purpose, the technical solution of the surface-mounted thin film fuse structure of the present invention is that at least one side of an insulating substrate is provided with a fuse circuit structure, and the fuse circuit structure is located between two corresponding electrode parts. A fuse link is connected between them, so that when the excess current passes through the fuse link, it will generate a high temperature or a specific temperature to cause a fuse, so as to achieve the circuit protection effect of blocking the excess current; wherein, the fuse link and the insulating base There is at least one space between the materials.

The beneficial effect of the utility model is: the heat source generated after the melting link part is energized will not be dissipated through the heat conduction of the insulating base material, so as to ensure the effect of melting when reaching a specific current or specific temperature, and then ensure the effect of circuit protection.

Description of drawings

FIG. 1 is a schematic structural diagram of a conventional surface mount fuse;

Fig. 2 is the structure schematic diagram of the surface bonding thin film fuse in the utility model;

Fig. 3 is a perspective view of the structure of the surface bonding thin film fuse in the present invention;

4 to 9 are schematic diagrams of the forming structure of the surface-mounted film fuse in the present invention;

10 to 11 are schematic diagrams of another molding structure of the surface-mounted film fuse in the present invention;

Fig. 12 is a schematic diagram of another molding structure of step B in the utility model;

Figure 13 is a schematic structural view of a surface-mounted film fuse that can be used on both sides in the utility model;

Figure 14 is a schematic structural view of a surface-mounted film fuse that can be used sideways in the utility model;

Fig. 15 is another structural schematic diagram of a surface-mounted film fuse that can be used on both sides in the present invention;

FIG. 16 is a schematic diagram of another structure of the surface-mount thin film fuse that can be used on the side of the present invention.

【Description of figure number】

Insulation substrate 11 Electrode part 12

Melting link part 13 tin layer 14

Protective Layer 15 Surface Mount Thin Film Fuse Structure 2

Insulation Substrate 21 Fuse Line Architecture 22

Electrode part 221 Melt link part 222

Conductive part 223 Tin layer 23

Protection Layer 24 Space 25

Nickel layer 26 Tin layer 27

Interval layer 31 Copper layer 32

Electroless Copper Layer 321 Electroplated Copper Layer 322

Photoresist 33 Second spacer layer 34

Detailed ways

The features of the utility model can be clearly understood by referring to the detailed description of the drawings and the embodiments.

The utility model "surface-mounted thin film fuse structure", wherein, the surface-mounted thin film fuse structure 2 is shown in Figure 2 and Figure 3, at least one side of an insulating substrate 21 is provided with a fuse circuit frame 22, here The fuse circuit structure 22 connects a melting link part 222 between two corresponding electrode parts 221, and the middle part of the surface of the melting link part 222 is provided with a tin layer 23, and the melting link part 222 of the fuse circuit structure A protective layer 24 is provided to prevent oxidation of the melting link part 222 and the tin layer 23 and to prevent molten metal from splashing out, wherein at least one space 25 is provided between the melting link part 222 and the insulating substrate 21, so that the melting link part 222 The non-direct contact with the insulating base material 21 prevents the heat source of the melting link part 222 from being dissipated through heat conduction through the insulating base material 21, so as to ensure that the melting link part achieves the circuit protection effect of blocking excess current due to high temperature melting.

Figures 4 to 9 are schematic diagrams of the forming structure of the surface-mounted film fuse structure of the present invention, which includes the following steps:

Step A, providing an insulating substrate 21 , as shown in FIG. 4 , the insulating substrate 21 may be a substrate such as epoxy resin fiberglass, polyimide or polyimide glass fiber, or ceramics.

Step B, disposing a spacer layer 31 on at least one side of the insulating substrate 21 , as shown in the figure, disposing a spacer layer 31 on the upper surface of the insulating substrate 21 , and the spacer layer 31 is disposed at a position where a fusion link is to be formed.

Step C, setting the copper layer 32, the side of the insulating substrate 21 is provided with a spacer layer 31, fully covered with the copper layer 32, as shown in Figure 5, and the step C further includes: steps C1 and C2, the step C1 Carrying out the process of depositing copper, the insulating substrate 21 is provided with a spacer layer 31 and one side is fully covered with the electroless copper layer 321, and step C2 performs the electroplating copper process, and the surface of the electroless copper layer 321 is covered with the electroplated copper layer 322, so as to The copper layer 32 structure is formed by the electroless copper layer 321 and the electroplated copper layer 322 .

Step D, coating a photoresist 33 on the copper layer 32, as shown in FIG. 6, and performing exposure, development, and etching, so that the copper layer forms a fuse circuit framework 22. The frame 22 includes two corresponding electrode portions 221 and a melting link portion 222 connecting the two electrode portions 221 .

Step E, removing the spacer layer 31, the spacer layer 31 can be a photoresist material, the photoresist can be a dry film or wet film photoresist, and the remaining photoresist 33 on the fuse circuit structure 22 and the spacer layer 31 can be used The chemical solvent is removed together, so that at least one space 25 is formed between the melting link portion 222 and the insulating substrate 21 , as shown in FIG. 8 .

Step F, disposing the tin layer 23 , as shown in FIG. 9 , disposing the tin layer 23 at the middle part of the surface of the melting link portion 222 .

Step G, disposing a nickel layer 26 and a tin layer 27 , and sequentially disposing the nickel layer 26 and the tin layer 27 on the surface of the electrode portion 221 .

Step H, setting the protection layer 24 , the protection layer 24 is provided at the melting link part 222 of the fuse circuit structure, and the surface mount thin film fuse structure 2 is completed.

Furthermore, in step F, a second spacer layer 34 can be further provided above the melting link portion 222 and the tin layer 23, as shown in FIG. hot-melt material, and after the protective layer 24 is set on the second spacer layer 34, the second spacer layer 34 is removed by heating, so that at least A space 25, as shown in Figure 11.

In addition, in another embodiment of the middle spacer layer of the present invention, the spacer layer can also be a water-resistant material, and the spacer layer is removed in step E by high-pressure water washing or chemical solvent cleaning to remove the spacer layer, and then the chemical solvent is used to remove the spacer layer. The remaining photoresist on the fuse circuit structure is removed, and then steps F to H are performed sequentially, and the surface mount thin film fuse structure 2 as shown in FIG. 9 can also be completed.

Furthermore, in another embodiment of the middle spacer layer of the present utility model, the spacer layer can be a hot-melt material, and the melting point of the spacer layer is lower than the melting point of the tin layer. In step E, the spacer layer is removed and the spacer layer is removed by heating. Remove, and then use a chemical solvent to remove the remaining photoresist on the fuse circuit structure, and step F is further included between step D and step E, and after step F, steps G to H are performed in sequence, and the same can be done as follows The structure 2 of the surface mount thin film fuse shown in FIG. 9 .

In addition, in another embodiment shown in FIG. 12 , in step B, a spacer layer 31 is respectively provided on the two board surfaces of the insulating substrate 21, and the spacer layer 31 can be a photoresist material as in the above-mentioned embodiments. , hot-melt material or water-resistant material, and carry out steps C to H in sequence, then the surface-mounted film fuse structure 2 that can be used on both sides as shown in Figure 13 is completed, so that the two board surfaces of the insulating substrate 21 are respectively set There is a fuse circuit structure 22 formed by connecting two corresponding electrode parts 221 with a melting link part 222; of course, in the step F, the protective layer 24, the melting link part 222 and the tin At least one space 25 is formed between the layers 23 , as shown in FIG. 15 , so as to complete another surface mount thin film fuse structure 2 that can be used on both sides.

Furthermore, in another embodiment shown in FIG. 12 , step C～H is performed sequentially, and step I is further included. The step I is to set up a conductive part. As shown in FIG. A conductive part 223 is provided to connect the corresponding electrode parts 221 of the two board surfaces, and step G and step H are performed sequentially after step I, and the surface-adhesive film that can be used on the side as shown in Figure 14 is completed Fuse structure 2, wherein, the step G is to provide a nickel layer and a tin layer, and the surface of the electrode part 221 and the conductive part 223 is sequentially provided with a nickel layer 26 and a tin layer 27, and the step H is to provide a protective layer 24; Of course, in the step F, at least one space 25 can also be formed between the protective layer 24, the melting link portion 222 and the tin layer 23, as shown in FIG. 16, and another surface that can be used on the side is completed. Bonding type thin film fuse structure 2.

It is worth mentioning that this utility model can improve the structure of the conventional surface-mounted thin film fuse, the contact between the melting link and the insulating substrate, so that part of the heat source generated by the energization of the melting link will pass through The insulating base material is dissipated due to heat conduction, so that the melting link part cannot reach a specific high temperature and be fused, and then the circuit protection effect of blocking excess current cannot be achieved, so that the electronic circuit of the electrical device is damaged or burned, and the utility model Through the non-contact setting between the melting link part and the insulating substrate, the heat source generated after the melting link part is energized will not dissipate through the heat conduction of the insulating substrate, so as to ensure the effect of melting at a specific current or a specific temperature , and then indeed maintain the effect of circuit protection.

The technical content and technical features of the present utility model have been disclosed above, but those who are familiar with the technology may still make various replacements and modifications based on the disclosure of the utility model without departing from the spirit of the utility model of the present case. Therefore, the protection scope of the present utility model should not be limited to those disclosed in the embodiments, but should include various replacements and modifications that do not deviate from the present utility model, and are covered by the scope of the following patent applications.

Claims (7)

1, a kind of surface bonding type film fuse structure, the wherein one side at an insulating substrate is provided with the fuse line architecture at least, and this fuse line architecture connects a melting chain part between two corresponding electrode part; It is characterized in that:

Be provided with at least one space between this melting chain part and insulating substrate.

2, surface bonding type film fuse structure according to claim 1 is characterized in that, two plate faces of this insulating substrate are respectively equipped with and utilize melting chain part to be connected between two corresponding electrode part and the fuse line architecture that constitutes.

3, as surface bonding type film fuse structure as described in the claim 2, it is characterized in that this insulating substrate dual-side further is provided with the conductive part that two corresponding electrode part of plate face are connected.

4, as surface bonding type film fuse structure as described in the claim 3, it is characterized in that this electrode part and conductive part surface are formed with nickel dam and tin layer.

5, surface bonding type film fuse structure as claimed in claim 1 or 2 is characterized in that the surperficial middle part of this melting chain part is provided with the tin layer.

6, as surface bonding type film fuse structure as described in the claim 1,2 or 3, it is characterized in that respectively the melting chain part place of this fuse line architecture is provided with in order to prevent the melting chain part oxidation and to prevent the protective layer that motlten metal spills.

7, as surface bonding type film fuse structure as described in the claim 1,2 or 3, it is characterized in that this protective layer and this melting chain part and this tin interlayer are formed with at least one space.

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