CN219893513U - Via hole fusing protection architecture 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

Via hole fusing protection architecture and PCB board

Technical Field

The utility model relates to the technical field of Printed Circuit Boards (PCB), in particular to a via fusing protection structure and a PCB.

Background

With the development of cloud computing applications, informatization is gradually covered to various fields of society. The daily work and life of people are more and more communicated through networks, the network data volume is also continuously increased, the power consumption of a server is higher and higher, namely the current is higher and higher, and the burning accidents frequently occur due to factors such as heating damage of electronic devices used on the server electronic equipment, poor PCB processing and the like.

Currently, designers often solve the problem of short-circuiting in this area by adding an overcurrent protection circuit near the main power supply, but cannot solve the burn-in risk of all electronic devices on the PCB. Therefore, a protection structure capable of comprehensively protecting the PCB is needed.

Disclosure of Invention

The applicant finds that at present, almost all metal structures on other layers are connected together through copper foils and through holes on a PCB to form a power supply network, so that the problem of board burning caused by device damage can be solved by disconnecting the connection relation between the surface layer of the through hole and the other layers.

The utility model aims to provide a via hole fusing protection structure and a PCB, which can realize the automatic fusing of a surface copper foil and an inner copper foil of a via hole of the PCB when heated, can not damage a laminated structure and a metal structure of the PCB, and can not need to additionally add a protection circuit.

In order to achieve the above object, an aspect of the present utility model provides a via fuse protection structure, at least including: 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.

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

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

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

Further, the metal material fills the via hole.

Further, the grooves are obtained in a drilling mode.

Further, the grooves are obtained in an etching mode.

Further, the novel aluminum foil structure further comprises a third copper foil layer, wherein the third copper foil layer is located on one side, away from the groove, of the second copper foil layer.

Further, the novel aluminum foil comprises a fourth copper foil layer, and the fourth copper foil layer is located on one side, away from the groove, of the third copper foil layer.

On the other hand, the utility model provides a PCB board, which comprises the via fusing protection structure.

Therefore, according to the technical scheme provided by the utility model, the temperature range of the normal work of the PCB is-10-65 ℃, so that the metal material is in a solid state in the via hole, and the first copper foil layer can be well conducted with the copper foil on the wall of the via hole. Under the condition that the positive electrode and the negative electrode of the power supply are short-circuited due to devices or other factors, the current in a conductive path formed by the copper foil and the metal material can be rapidly increased, meanwhile, the temperature can be rapidly increased, and the melting point of the metal material is rapidly reached, so that solid aluminum ladder alloy metal is changed into liquid state and flows out of the through hole, a first copper foil layer on the surface of the through hole is disconnected with a copper foil on the hole wall, at the moment, the annular groove cuts off the conductive path between the Kong Biaoceng bonding pad and the copper sheet on the hole wall, the temperature is not increased, and the PCB and the electronic devices are effectively protected.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a cross-sectional view of a prior art PCB structure;

FIG. 2 is a cross-sectional view of a via fuse protection structure provided by the present utility model;

FIG. 3 is a cross-sectional view of a via fuse protection structure provided by the present utility model;

FIG. 4 is a cross-sectional view of a via fuse protection structure provided by the present utility model;

FIG. 5 is a cross-sectional view of a via fuse protection structure provided by the present utility model;

FIG. 6 is a cross-sectional view of a via fuse protection structure provided by the present utility model;

FIG. 7 is a cross-sectional view of a via fuse protection structure provided by the present utility model;

FIG. 8 is a cross-sectional view of a via fuse protection structure provided by the present utility model;

FIG. 9 is a cross-sectional view of a via fuse protection structure provided by the present utility model;

FIG. 10 is a cross-sectional view of a via fuse protection structure provided by the present utility model;

FIG. 11 is a schematic diagram illustrating a process of manufacturing a fuse protection structure for a via according to the present utility model;

FIG. 12 is a schematic diagram of a process for fabricating a fuse protection structure for a via according to the present utility model;

FIG. 13 is a schematic diagram of a process for fabricating a fuse protection structure for a via according to the present utility model;

FIG. 14 is a schematic diagram of a process for fabricating a fuse protection structure for vias according to the present utility model;

fig. 15 is a schematic diagram of a processing procedure of a via fuse protection structure according to the present utility model.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present utility model and should not be construed as limiting the utility model.

In the description of the present utility model, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

Unless specifically stated or limited otherwise, the terms "mounted," "connected," and "fixed" are to be construed broadly, and may be, for example, either fixed or removable; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

Unless expressly stated or limited otherwise, a first feature being "above" or "below" a second feature may include the first feature and the second feature being in direct contact, or may include the first feature and the second feature not being in direct contact but being in contact with each other by way of additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

With the development of cloud computing applications, informatization is gradually covered to various fields of society. The daily work and life of people are more and more communicated through networks, the data volume of the networks is also continuously increased, and the power consumption of the server is higher and higher, namely the current is higher and higher. The electronic devices used on the server electronic equipment are heated and damaged, and the burn-in accidents frequently occur due to factors such as poor PCB processing and the like. Designers solve the problem of short circuit in this area by adding an overcurrent protection circuit near the main power supply, but cannot solve the board burning risk of all electronic devices on the PCB board.

The applicant found through research that, as shown in fig. 1, almost all electronic devices 4 are designed on the surface of a PCB at present, metal pins of the devices are connected with metal structures of other layers through copper foils 21 and vias 10 on the PCB to form a power supply network, the melting point of copper is 1083 ℃, and even if the PCB is burnt, the copper on the walls of the vias cannot be broken. Therefore, the problem of board burning caused by device damage can be solved by disconnecting the connection relation between the surface layer of the via hole and other layers.

Therefore, the utility model provides the via hole fusing protection structure and the PCB, which can realize the automatic fusing of the surface copper sheet and the inner copper sheet of the via hole of the PCB when heated, can not damage the laminated structure and the metal structure of the PCB, and does not need to additionally add a protection circuit. Reliable protection measures are provided for the design, and the space of the board card occupied by the electronic device of the protection circuit and the cost of the part of the device are saved. From the viewpoint of the cost of the PCB, the method does not bring about the cost rise of the PCB.

Referring to fig. 2 to 10, in one implementation, the via fusing protection structure at least includes: a substrate 1, wherein the substrate 1 is provided with a via 10 penetrating through the substrate; a first copper foil layer 21 and a second copper foil layer 22 sequentially arranged along the thickness direction of the substrate 1, wherein the first copper foil layer 21 is positioned on the upper surface of the substrate 1 and is connected with metal pins of the electronic component 4, and the second copper foil layer 22 is connected with the first copper foil layer 21 through the via hole 10; and the fusing layer 3 comprises an annular groove 30 arranged on the inner wall of the via hole and a metal material 31 covering the annular groove and having a melting point of 80-220 ℃, wherein the annular groove 30 is positioned between the first copper foil layer 21 and the second copper foil layer 22.

Because the temperature interval of the normal work of the PCB is-10 ℃ to 65 ℃, the metal material 31 is in a solid state in the via 10, and can well lead the first copper foil layer 21 to be communicated with the copper foil 101 on the wall of the via hole. Under the condition that the positive electrode and the negative electrode of the power supply are short-circuited due to the device or other factors, the current in the conductive path formed by the copper foil and the metal material 31 is rapidly increased, meanwhile, the temperature is also rapidly increased, and the melting point of the metal material 31 is rapidly reached, so that the solid aluminum ladder alloy metal is changed into a liquid state and flows out of the through hole, the first copper foil layer 21 on the surface of the through hole is disconnected from the hole wall copper foil 101, and at the moment, the annular groove 30 cuts off the conductive path between the Kong Biaoceng bonding pad and the hole wall copper sheet, the temperature is not increased any more, and the PCB and the electronic device are effectively protected.

The second copper foil layer 22 may be the lower surface of the PCB board, and in this case, the fusing layer 3 may be disposed as shown in fig. 2 to 5; when the PCB board has an inner copper foil, as shown in fig. 6 to 9, the inner copper foil may have one or more layers, and in this case, the second copper foil layer 22 may be the inner copper foil closest to the first copper foil layer.

In one possible embodiment, the metal material 31 may be selected from tin alloys, such as solder, or may also be selected from aluminum ladder alloys.

If the annular groove is too narrow, it may be disadvantageous that the metal material is not easily flowed out to remain in the annular groove after melting. In one possible embodiment, the width of the annular groove in the direction perpendicular to the first copper foil layer is between 3mi and 5 mi. The above embodiment is more beneficial to the outflow of the metal material from the annular groove, so that the metal material 31 can be ensured to rapidly flow out of the annular groove 30 after reaching the melting point and becoming liquid, so that the annular groove timely breaks the passage between the first copper foil layer 21 and the second copper foil layer 22.

In one embodiment, since the size of the via hole is generally small, in order to prevent the metal material 31, which becomes a liquid state, from not being thoroughly removed from the downward flow, and thus from remaining in the annular groove 30, it may be disposed in a direction perpendicular to the first copper foil layer such that the distance of the annular groove from the upper surface of the substrate is smaller than the distance of the annular groove from the lower surface of the substrate. I.e. along the depth of the via, the annular recess is located in the upper half of the via. In this way, the molten metal material is more thoroughly detached from the annular groove, without the molten metal material accumulating on the lower surface of the substrate and remaining in the annular groove.

The utility model also provides a processing method of the via fusing protection structure.

Taking the via fuse protection structure of fig. 2 as an example, it is assumed that the via package is designed such that the apertures of the first copper foil layer 21 and the second copper foil layer 22 are 14mi, and the remaining inner layer hole diameters remain 10 mi.

Please refer to fig. 10 to fig. 14.

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 14mi, the diameter of the cylindrical hole is 10mi, and in order to ensure the adhesion between the copper foil on the upper surface of the via hole position and the PCB substrate 1, the first copper foil layer 21 on the upper surface of the via hole can be set to have a diameter greater than 24mi, and the diameter of the copper foil layer on the lower surface of the via hole can be designed to be at least 20 mi. During PCB processing, a drill bit with the diameter of 10mi is firstly adopted to drill through the base plate 1, and the drilled PCB needs to be sufficiently cleaned to remove drilling residues, as shown in FIG. 11.

After the cleaning, copper plating treatment is performed on the via 10, copper foil is left attached to the wall and the upper and lower surfaces of the via, and the cleaned PCB is subjected to electroplating treatment, so that copper foil with a thickness of 1mi is attached to the surface and the wall of the via, as shown in FIG. 12.

The PCB is placed in the etching solution, the copper sheet shape designed on the surface of the PCB is etched, and the through hole part is etched as shown in figure 13.

Then the via hole is drilled a second time using a drill bit of 14 ml diameter from the first copper foil layer 21 to the second copper foil layer 22 of the PCB, and since the second drill hole has a larger diameter than the first drill hole and the drilled hole is not a through hole structure, an annular groove 30 is formed on the inner wall of the via hole 10, as shown in fig. 14, so that the first copper foil layer 21 is disconnected from the second copper foil layer 22.

The metal material 31 is inserted into the annular groove 30, so that the annular groove 30 is completely covered, and the first copper foil layer 21 and the second copper foil layer 22 are conducted again. Taking aluminum ladder alloy metal with the melting point of 98 ℃ as an example, the aluminum ladder alloy metal is plugged into the conical hole and the cylindrical hole, and the copper foil on the upper surface of the via hole is covered with the aluminum ladder alloy metal with the thickness of 1mi, so that the first copper foil on the upper surface of the via hole is communicated with the hole wall copper foil 101 through the aluminum ladder alloy metal. As shown in fig. 15. Because the normal working temperature interval of the PCB is-10-65 ℃, the aluminum ladder alloy cannot be melted in the through hole, and the first copper foil layer 21 and the second copper foil layer 22 are conducted. Under the condition that the positive electrode and the negative electrode of the power supply are short-circuited due to devices or other factors, the current in the conductive path can be rapidly increased, meanwhile, the temperature can be rapidly increased, the melting point of the aluminum ladder alloy metal can be rapidly reached, and the aluminum ladder alloy metal can be changed into liquid state to flow out of the through hole, so that a bonding pad on the surface of the through hole is disconnected with a hole wall copper sheet, the conductive path is cut off, the temperature is not increased any more, the PCB and the electronic devices are effectively protected, and the reliability is high. The size data provided in the present embodiment is merely an example for explaining the structure of the present utility model, and is not intended as a limitation of the present utility model.

The annular groove 30 may be formed by drilling in the above embodiment, or may be etched in the hole wall copper foil 101 on the inner wall of the via hole.

In one implementation, the metal material 31 may fill the via hole 10, or may cover only the annular groove 30, as shown in fig. 5 and 8, and may enable the first copper foil layer 21 to be electrically connected to the second copper foil layer 22.

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

Further, the novel aluminum foil comprises a fourth copper foil layer, and the fourth copper foil layer is located on one side, away from the groove, of the third copper foil layer.

On the other hand, the utility model also provides a PCB board, which comprises the via fusing protection structure.

The via fusing protection structure and the PCB provided by the utility model can replace a short-circuit protection circuit designed on the PCB, save the cost of a protection circuit device, save the space occupied by the protection circuit device on the PCB, and realize other circuit functions on the PCB by utilizing the space; the via fusing protection structure can be applied to any power network on the PCB, does not cause the cost rise of the PCB, and has wide application range; the melting point of the metal material of the fusion layer is higher than the normal working temperature of the PCB and is far lower than the burning temperature of the PCB, so that the PCB can be completely protected after fusion, and the reliability is high.

The foregoing description of the preferred embodiments of the utility model is not intended to limit the utility model to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the utility model are intended to be included within the scope of the utility model.

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.