CN219893513U - A through-hole fuse protection structure and PCB board - Google Patents

Abstract

The utility model discloses a via fusing protection structure and a PCB, wherein the via fusing protection structure at least comprises: a substrate having a via penetrating the substrate; the first copper foil layer is positioned on the upper surface of the substrate and is connected with metal pins of the electronic component, and the second copper foil layer is connected with the first copper foil layer through the via hole; and the fusing layer comprises an annular groove arranged on the inner wall of the via hole and a metal material covering the annular groove and having a melting point of 80-220 ℃, wherein the annular groove is positioned between the first copper foil layer and the second copper foil layer. The metal material of the fusion layer is in a solid state under normal conditions, so that the first copper foil layer is communicated with the copper foil of the via hole wall. When short circuit, the copper foil becomes liquid at high temperature and flows out of the through hole, so that the first copper foil layer is disconnected with the copper foil on the hole wall, and the PCB and the electronic device are protected.

Description

A through-hole fuse protection structure and PCB board

Technical field

The utility model relates to the technical field of PCB boards, specifically to a through-hole fuse protection structure and a PCB board.

Background technique

With the development of cloud computing applications, informatization has gradually covered all areas of society. People communicate more and more through the Internet in their daily work and life, and the amount of network data is also increasing. The power consumption of servers is getting higher and higher, which means that the current is getting larger and larger. The electronic devices used in server electronic equipment Heat damage, poor PCB board processing and other factors cause board burnout accidents to occur frequently.

At present, designers often solve the short circuit problem in this area by adding overcurrent protection circuits near the main power supply, but this cannot solve the risk of board burnout for all electronic devices on the PCB. Therefore, there is an urgent need for a protection structure that can comprehensively protect the PCB board.

Utility model content

The applicant found through research that at present, almost all copper foil and via holes on the PCB are connected to the metal structures on other levels to form a power supply network. Therefore, disconnecting the connection relationship between the surface layer of the via holes and other levels can Solve the problem of board burnout caused by device damage.

The purpose of this application is to provide a through-hole fuse protection structure and a PCB board that can realize automatic fusing of the surface copper foil and the inner copper foil of the PCB board via hole when heated, without damaging the lamination structure and metal structure of the PCB board, and also No additional protection circuit is required.

In order to achieve the above object, the present application provides a through-hole fuse protection structure on the one hand, which at least includes: a substrate having a via hole penetrating the substrate; a first copper foil layer and a second copper foil layer sequentially arranged along the thickness direction of the substrate. A copper foil layer, the first copper foil layer is located on the upper surface of the substrate and is connected to the metal pins of the electronic components, and the second copper foil layer is connected to the first copper foil layer through the via hole; The fuse layer includes an annular groove provided on the inner wall of the via hole and a metal material covering the annular groove with a melting point between 80-220 degrees Celsius, wherein the annular groove is located on the first copper foil layer and the second copper foil layer.

Further, the metal material is tin alloy or aluminum ladder alloy.

Further, the width of the annular groove in a direction perpendicular to the first copper foil layer is between 3 mil and 5 mil.

Further, in a direction perpendicular to the first copper foil layer, the distance between the annular groove and the upper surface of the substrate is smaller than the distance between the annular groove and the lower surface of the substrate.

Further, the metal material fills the via hole.

Further, the groove is obtained by drilling.

Further, the groove is obtained by etching.

Further, a third copper foil layer is included, and the third copper foil layer is located on a side of the second copper foil layer away from the groove.

Further, a fourth copper foil layer is included, and the fourth copper foil layer is located on a side of the third copper foil layer away from the groove.

On the other hand, the present application provides a PCB board, which includes the via-hole fuse protection structure described above.

It can be seen that the technical solution provided by the present utility model, since the normal operating temperature range of the PCB board is -10°C ~ 65°C, the metal material is solid in the via hole, and can well make the first copper foil layer and The copper foil on the via hole wall is conductive. When the positive and negative electrodes of the power supply are short-circuited due to devices or other factors, the current in the conductive path formed by the copper foil and metal materials will rise sharply, and the temperature will also rise rapidly, reaching the melting point of the metal materials quickly, thus causing the The solid aluminum ladder alloy metal becomes liquid and flows out of the via hole, causing the first copper foil layer on the surface of the via hole to disconnect from the copper foil on the hole wall. At this time, the annular groove cuts off the surface pad of the via hole and the hole wall. The conductive path between the copper sheets prevents the temperature from rising, effectively protecting the PCB board and electronic devices.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a cross-sectional view of a PCB board structure in the prior art;

Figure 2 is a cross-sectional view of a through-hole fuse protection structure provided by the utility model;

Figure 3 is a cross-sectional view of a through-hole fuse protection structure provided by the utility model;

Figure 4 is a cross-sectional view of a through-hole fuse protection structure provided by the utility model;

Figure 5 is a cross-sectional view of a through-hole fuse protection structure provided by the utility model;

Figure 6 is a cross-sectional view of a through-hole fuse protection structure provided by the utility model;

Figure 7 is a cross-sectional view of a through-hole fuse protection structure provided by the utility model;

Figure 8 is a cross-sectional view of a through-hole fuse protection structure provided by the utility model;

Figure 9 is a cross-sectional view of a through-hole fuse protection structure provided by the utility model;

Figure 10 is a cross-sectional view of a through-hole fuse protection structure provided by the utility model;

Figure 11 is a schematic diagram of the processing process of a through-hole fuse protection structure provided by the utility model;

Figure 12 is a schematic diagram of the processing process of a through-hole fuse protection structure provided by the utility model;

Figure 13 is a schematic diagram of the processing process of a through-hole fuse protection structure provided by the utility model;

Figure 14 is a schematic diagram of the processing process of a through-hole fuse protection structure provided by the utility model;

Figure 15 is a schematic diagram of the processing process of a through-hole fuse protection structure provided by the utility model.

Detailed ways

The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the drawings, in which the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and intended to explain the present invention, but should not be understood as limiting the present invention.

In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner" and "outer" The indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. They are not intended to indicate or imply that the device or element referred to must have a specific orientation or a specific orientation. The orientation structure and operation of the invention cannot be construed as limitations of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

Unless otherwise expressly stipulated and limited, the terms "installation", "connection", "connection" and "fixing" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or a detachable connection. It can be an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components or an interaction between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Unless otherwise expressly provided and limited, "above" or "below" a first feature on a second feature may include the first feature and the second feature being in direct contact, or it may include that the first feature and the second feature are not in direct contact. Rather, it is through additional characteristic contact between them. Furthermore, the terms "above", "above" and "above" a first feature on a second feature include the first feature being directly above and diagonally above the second feature, or simply mean that the first feature is higher in level than the second feature. “Below”, “under” and “under” the first feature is the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature is less horizontally than the second feature.

With the development of cloud computing applications, informatization has gradually covered all areas of society. People communicate more and more through the Internet in their daily work and life, and the amount of network data is also increasing. The power consumption of servers is getting higher and higher, which means that the current is getting larger and larger. Burnout accidents occur frequently due to factors such as thermal damage to electronic devices used in server electronic equipment and poor processing of PCB boards. Designers solve the short circuit problem in this area by adding an overcurrent protection circuit near the main power supply, but this does not solve the risk of burn-in for all electronic devices on the PCB.

The applicant found through research that, as shown in Figure 1, at present, almost all electronic devices 4 are designed on the surface of the PCB board, and the metal pins of the devices are connected to the metal structures at other levels through the copper foil 21 and via holes 10 on the PCB board. Connected together to form a power supply network, the melting point of copper is 1083°C. Even if the PCB board burns, the copper on the wall of the via hole will not be disconnected. Therefore, disconnecting the via surface layer from other layers can solve the problem of board burnout caused by device damage.

To this end, the utility model proposes a through-hole fuse protection structure and a PCB board, which can realize automatic fusing of the surface copper layer and the inner layer copper layer of the PCB board via hole when heated, without damaging the lamination structure and metal structure of the PCB board. There is no need to add additional protection circuits. It provides reliable protection measures for the design, saving the board space occupied by the protection circuit electronic devices and the cost of this part of the device. From the perspective of PCB board cost, this method will not increase the cost of PCB board.

Please refer to Figures 2 to 10. In an implementable implementation, the via hole fuse protection structure at least includes: a substrate 1, the substrate 1 having a via hole 10 penetrating the substrate; arranged sequentially along the thickness direction of the substrate 1 The first copper foil layer 21 and the second copper foil layer 22 are located on the upper surface of the substrate 1 and connected to the metal pins of the electronic component 4, and the second copper foil layer 22 Connected to the first copper foil layer 21 through the via hole 10; the fuse layer 3 includes an annular groove 30 provided on the inner wall of the via hole and a melting point covering the annular groove at 80-220 The metal material 31 is between degrees Celsius, wherein the annular groove 30 is located between the first copper foil layer 21 and the second copper foil layer 22 .

Since the normal operating temperature range of the PCB board is -10°C to 65°C, the metal material 31 is solid in the via hole 10 and can well conduct the first copper foil layer 21 to the via hole wall copper foil 101 . When the positive and negative electrodes of the power supply are short-circuited by devices or other factors, the current in the conductive path formed by the copper foil and the metal material 31 will rise sharply, and the temperature will also rise rapidly, quickly reaching the melting point of the metal material 31 , so that the solid aluminum ladder alloy metal becomes liquid and flows out of the via hole, causing the first copper foil layer 21 on the surface of the via hole to disconnect from the hole wall copper foil 101. At this time, the annular groove 30 cuts off the via hole The conductive path between the surface pad and the hole wall copper skin no longer increases the temperature, effectively protecting the PCB board and electronic devices.

The second copper foil layer 22 can be the lower surface of the PCB board. At this time, the arrangement of the fuse layer 3 can be as shown in Figures 2 to 5; when the PCB board has an inner layer of copper foil, as shown in Figures 6 to 9 , the inner copper foil may have one layer or multiple layers. In this case, the second copper foil layer 22 may be the inner copper foil closest to the first copper foil layer.

In an implementable implementation, the metal material 31 can be a tin alloy, such as solder, or an aluminum ladder alloy.

If the annular groove is too narrow, it may be difficult for the metal material to melt and flow out easily and remain in the annular groove. In an implementable implementation, the width of the annular groove along a direction perpendicular to the first copper foil layer is between 3 mil and 5 mil. The above embodiment is more conducive to the flow of metal material from the annular groove, thereby ensuring that the metal material 31 can quickly flow out of the annular groove 30 after reaching the melting point and becoming liquid, so that the annular groove can promptly remove the first copper foil layer The path between 21 and the second copper foil layer 22 is disconnected.

In an achievable implementation, since the size of the via hole is generally relatively small, in order to prevent the metal material 31 that becomes liquid from flowing downward incompletely and thus remaining in the annular groove 30, it can be arranged vertically. In the direction of the first copper foil layer, the distance between the annular groove and the upper surface of the substrate is smaller than the distance between the annular groove and the lower surface of the substrate. That is, along the depth direction of the via hole, the annular groove is located in the upper half of the via hole. In this way, the melted metal material is detached from the annular groove more completely, and the melted metal material does not accumulate on the lower surface of the substrate and remain in the annular groove.

The utility model also provides a processing method of the above-mentioned through-hole fuse protection structure.

Taking the via-hole fuse protection structure in Figure 2 as an example, it is assumed that the via-hole package is designed such that the first copper foil layer 21 and the second copper foil layer 22 have apertures of 14 mil, and the remaining inner layer drilling apertures remain at 10 mil.

Please also refer to Figures 10 to 14.

First, the shape of the via hole 10 is designed to be tapered at the upper end and cylindrical at the lower end. The maximum diameter of the tapered hole part is 14 mi l, and the diameter of the cylindrical hole is 10 mi l. In order to ensure that the copper foil on the upper surface of the via hole position is in contact with the PCB board substrate With an adhesion of 1, the size of the first copper foil layer 21 on the upper surface of the via hole can be set to a diameter greater than 24 mil, and the diameter of the copper foil layer on the lower surface of the via hole is designed to be at least 20 mil. During PCB processing, first use a 10 mil diameter drill bit to drill through the substrate 1. The completed PCB board needs to be fully cleaned to remove drilling residue, as shown in Figure 11.

After the cleaning is completed, the via 10 is copper-plated, leaving copper foil attached to the via hole wall and upper and lower surfaces. The cleaned PCB board is electroplated so that the via hole surface and via hole wall are adhered to with a thickness of 1mi l copper foil, as shown in Figure 12.

Place the PCB board in the etching solution and etch out the designed copper shape on the surface of the PCB board. The via hole part is etched as shown in Figure 13.

Then drill the via hole for the second time, using a 14 mil diameter drill bit to drill from the first copper foil layer 21 to the second copper foil layer 22 of the PCB. Since the second drilling hole diameter is larger than the first drilling hole diameter, Moreover, a non-through-hole structure is drilled, so an annular groove 30 is generated on the inner wall of the via hole 10, as shown in FIG. 14, so that the first copper foil layer 21 and the second copper foil layer 22 are disconnected.

The metal material 31 is stuffed into the annular groove 30 to completely cover the annular groove 30 so that the first copper foil layer 21 and the second copper foil layer 22 can be electrically connected again. Taking aluminum ladder alloy metal with a melting point of 98°C as an example, insert aluminum ladder alloy metal into tapered holes and cylindrical holes. The copper foil on the upper surface of the via hole is covered with aluminum ladder alloy metal with a thickness of 1 mil. The first copper foil on the surface and the hole wall copper foil 101 are electrically connected through aluminum ladder alloy metal. As shown in Figure 15. Since the normal operating temperature range of the PCB board is -10°C to 65°C, the aluminum ladder alloy will not melt in the via hole, and the first copper foil layer 21 and the second copper foil layer 22 are electrically connected. When the positive and negative electrodes of the power supply are short-circuited by a device or other factors, the current in the conductive path will rise sharply, and the temperature will also rise sharply, quickly reaching the melting point of the aluminum ladder alloy metal, thus turning into a liquid state from the via hole. It flows out, causing the pad on the surface of the via hole to disconnect from the copper skin on the hole wall, cutting off the conductive path, and the temperature no longer rises, effectively protecting the PCB board and electronic devices, with high reliability. The dimensional data provided in this embodiment is only used as an example to illustrate the structure of the present utility model, and is not used as a limitation of the present utility model.

The annular groove 30 can be processed by drilling as in the above embodiment, or by etching to etch an annular groove on the hole wall copper foil 101 on the inner wall of the via hole.

In an implementable manner, the metal material 31 can fill the via hole 10 , or can only cover the annular groove 30 , as shown in FIGS. 5 and 8 , and allows the first copper foil layer 21 to be in contact with the second copper foil layer 21 . The foil layer 22 can be electrically conductive.

Furthermore, a third copper foil layer may also be included, and the third copper foil layer is located on a side of the second copper foil layer away from the groove.

Further, a fourth copper foil layer is included, and the fourth copper foil layer is located on a side of the third copper foil layer away from the groove.

On the other hand, the utility model also provides a PCB board, which includes the above-mentioned via fuse protection structure.

The utility model proposes a through-hole fuse protection structure and PCB board, which can replace the short-circuit protection circuit designed on the PCB board, save the cost of the protection circuit device, and save the space occupied by the protection circuit device on the PCB board. Utilize this The space can be used to implement other circuit functions on the PCB board; this via-hole fuse protection structure can be applied to any power network on the PCB board without causing an increase in the cost of the PCB board and has a wide range of applications; the melting point of the metal material of the fuse layer is greater than that of the PCB board The normal operating temperature is much lower than the burning temperature of the PCB board material, so the PCB board can be completely protected after a fuse occurs, and the reliability is high.

The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection of the present application. within the range.

Claims (10)

1. A via fuse protection structure, comprising:

a substrate having a via penetrating the substrate;

the first copper foil layer is positioned on the upper surface of the substrate and is connected with metal pins of the electronic component, and the second copper foil layer is connected with the first copper foil layer through the via hole;

and the fusing layer comprises an annular groove arranged on the inner wall of the via hole and a metal material covering the annular groove and having a melting point of 80-220 ℃, wherein the annular groove is positioned between the first copper foil layer and the second copper foil layer.

2. The via fuse protection structure according to claim 1, wherein the metallic material is a tin alloy or an aluminum ladder alloy.

3. The via fuse protection structure of claim 1, wherein the annular groove has a width in a direction perpendicular to the first copper foil layer of between 3mil and 5 mil.

4. The via fuse protection structure according to claim 1, wherein the annular groove is at a smaller distance from the upper surface of the substrate than the annular groove is from the lower surface of the substrate in a direction perpendicular to the first copper foil layer.

5. The via fuse protection structure according to claim 1, wherein the metal material fills the via.

6. The via fuse protection structure according to claim 1, wherein the recess is obtained by drilling.

7. The via fuse protection structure according to claim 1, wherein the recess is obtained by etching.

8. The via fuse protection structure according to claim 1, further comprising a third copper foil layer, the third copper foil layer being located on a side of the second copper foil layer remote from the recess.

9. The via fuse protection structure according to claim 8, further comprising a fourth copper foil layer, the fourth copper foil layer being located on a side of the third copper foil layer remote from the recess.

10. A PCB board, characterized in that the PCB board comprises a via fuse protection structure according to any one of claims 1 to 9.