Circuit board tin printing structure

Abstract

The utility model relates to a circuit board tin printing structure. The circuit board tin printing structure comprises a PCB and a steel mesh layer, wherein the PCB is provided with a through hole; the steel mesh layer is arranged on the PCB, a tin printing hole is formed in the steel mesh layer, and the projection of the tin printing hole on the PCB does not coincide with the through hole. According to the scheme provided by the invention, the conditions of tin shortage and tin leakage caused by the fact that the solder paste flows into the through hole when the solder paste is subjected to a reflow soldering process can be avoided, so that effective welding of the bottom of the IC and the bottom bonding pad of the PCB is ensured, and a good heat dissipation effect is formed.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit boards, in particular to a tin printing structure for a circuit board. Background Art

[0002] Currently, ICs are mounted on PCBs by patch technology, and the patch process requires printing solder paste on a steel mesh for soldering. Therefore, the reliability of the steel mesh is particularly important.

[0003] In the related art, due to the IC E-PAD through-hole design of the PCB, after printing the solder paste patch, the solder paste will flow into the through-hole after reflow soldering, causing tin leakage or insufficient tin in the IC E-PAD. That is, due to the heating of the solder paste, the solder paste will flow from the pad through-hole on the front of the PCB to the back of the PCB, thereby reducing the contact area between the bottom of the IC and the PCB, making it impossible to ensure the effective soldering of the IC, and the heat generated by the IC during operation cannot be dispersed, resulting in the body of the IC being burned out due to excessive temperature during operation. Among them, the IC E-PAD is a grounding PIN. Utility Model Content

[0004] The utility model aims to overcome the deficiencies in the prior art and provide a circuit board tin printing structure, which can prevent the solder paste from having insufficient tin or tin leakage during the reflow soldering process, thereby ensuring the contact area between the bottom of the IC and the PCB board to form effective welding.

[0005] The purpose of this utility model is achieved through the following technical solutions:

[0006] The first aspect of the present application provides a circuit board tin printing structure, comprising: a PCB board, on which a through hole is opened; a steel mesh layer, which is arranged on the PCB board, and on which a tin printing hole is opened, and the projection of the tin printing hole on the PCB board does not overlap with the through hole.

[0007] The thickness of the steel mesh layer is in the range of 0.12 mm.

[0008] The horizontal distance from the through hole to the tin-printing hole ranges from 0.25 mm to 0.45 mm.

[0009] The cross-sectional structure of the tin-printing hole is a rectangular cross-sectional structure.

[0010] The cross-sectional structure of the tin-printing hole is a circular cross-sectional structure.

[0011] The diameter of the tin-printing hole ranges from 0.5 mm to 0.6 mm.

[0012] The cross-sectional structure of the through hole is a circular cross-sectional structure.

[0013] The diameter of the tin-printing hole is larger than the diameter of the through hole.

[0014] The steel mesh layer is provided with a plurality of tin-printing holes, and the PCB board is provided with a plurality of through holes, wherein the projection of each tin-printing hole on the PCB board does not overlap with each through hole.

[0015] The interval between every two adjacent solder holes is the same.

[0016] Compared with the prior art, the utility model has at least the following advantages:

[0017] The present application arranges the tin printing hole and the through hole to be non-overlapping. After the tin printing hole is printed with tin paste, during the reflow process, the tin paste adheres to the bottom of the IC during the melting process to form a good welding effect. In addition, since there is a certain distance between the tin printing hole and the through hole, the tin paste flows into the through hole after flowing, and will not flow to the other side of the PCB board to cause tin leakage, thereby ensuring the contact area between the bottom of the IC and the PCB board, forming a good welding, and ensuring effective heat dissipation of the IC during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for use in the embodiments are briefly introduced below.

[0019] Figure 1 This is a structural schematic diagram of a circuit board tin printing structure in one embodiment of the utility model;

[0020] Figure 2 It is a structural schematic diagram of another implementation of the circuit board tin printing structure in one embodiment of the utility model;

[0021] Figure 3 It is a structural schematic diagram of another implementation of the circuit board tin printing structure in one embodiment of the utility model. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0023] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0024] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0025] Due to the IC E-PAD through-hole design of the PCB, after printing the solder paste patch, the solder paste will flow into the through-hole after reflow soldering, causing tin leakage or insufficient tin in the IC E-PAD. That is, the solder paste will flow due to heating, and the solder paste will pass from the pad through-hole on the front of the PCB board to the back of the PCB board, thereby reducing the contact area between the bottom of the IC and the PCB board, making it impossible to ensure effective soldering of the IC. The heat generated by the IC during operation cannot be dispersed, and the IC body is burned out due to excessive temperature during operation.

[0026] In response to the above problems, an embodiment of the present application provides a circuit board tin printing structure, which can prevent the occurrence of insufficient tin or tin leakage at the bottom of the IC when the solder paste undergoes the reflow soldering process, thereby ensuring the contact area between the bottom of the IC and the PCB board, forming a good weld, and ensuring effective heat dissipation of the IC during operation.

[0027] The technical solution of the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0028] See also Figure 1 and Figure 2 A circuit board tin printing structure includes: a PCB board 100 and a steel mesh layer 200, the PCB board 100 is provided with a through hole 110; the steel mesh layer 200 is arranged on the PCB board 100, and the steel mesh layer 200 is provided with a tin printing hole 210, and the projection of the tin printing hole 210 on the PCB board 100 does not overlap with the through hole 110.

[0029] It should be noted that the steel mesh layer 200 is arranged on the PCB board 100, and the tin printing hole 210 is opened on the steel mesh layer 200. The tin printing hole 210 does not overlap with the through hole on the PCB board 100. The purpose is that after the tin printing hole 210 prints the solder paste, after the reflow process, and because there is a certain distance between the tin printing hole 210 and the through hole 110, the solder paste will not flow out of the through hole 110 and then flow to the other side of the PCB board 100, causing tin leakage. This ensures the contact area between the bottom of the IC and the PCB board 100, and also ensures that the heat of the IC can be effectively dissipated during operation.

[0030] See also Figure 2 In one embodiment, the thickness of the steel mesh layer 200 is in the range of 0.12 mm. It should be noted that the thickness of the steel mesh layer 200 of the present application is 0.12 mm, which can ensure a sufficient amount of solder paste.

[0031] See also Figure 1 In one embodiment, the horizontal distance from the through hole 110 to the solder printing hole 210 ranges from 0.25 mm to 0.45 mm.

[0032] It should be noted that the horizontal distance from the through hole 110 to the solder hole 210 is generally controlled to be 0.25 mm to 0.45 mm. Within this range, the solder paste will not flow out of the through hole 110 and onto the back of the PCB during reflow, and the firmness of the IC bottom soldering can be ensured.

[0033] See also Figure 3 In one embodiment, the cross-sectional structure of the solder hole 210 is a rectangular cross-sectional structure.

[0034] It should be noted that, in some IC structures, the shape of the solder printing hole 210 can be a rectangular hole, and the number of the rectangular holes is usually multiple, and their distribution is all centrally symmetrical.

[0035] See also Figure 2 In one embodiment, the cross-sectional structure of the tin-printing hole 210 is a circular cross-sectional structure. Specifically, the aperture of the tin-printing hole 210 ranges from 0.5 mm to 0.6 mm. Specifically, the cross-sectional structure of the through hole 110 is a circular cross-sectional structure. Specifically, the aperture of the tin-printing hole 210 is larger than the aperture of the through hole 110.

[0036] It should be noted that the cross-sectional structure of the tin-printing hole 210 can also be a circular cross-sectional structure, and the aperture range is 0.5mm to 0.6mm. At the same time, in order to ensure the amount of solder paste, the aperture of the tin-printing hole 210 is larger than the aperture of the through hole 110 to ensure the reliability and stability of IC welding.

[0037] See also Figure 2In one embodiment, a plurality of solder holes 210 are formed on the steel mesh layer 200, and a plurality of through holes 110 are formed on the PCB board 100, wherein the projection of each solder hole 210 on the PCB board 100 does not overlap with each through hole 110. Specifically, the intervals between each two adjacent solder holes 210 are the same.

[0038] It should be noted that the number of the solder holes 210 is usually an even number, and they are distributed in a centrally symmetrical manner, that is, the solder holes 210 are connected together to form a centrally symmetrical figure. This method can ensure the firmness of the IC during welding, so that the amount of solder paste on both sides of the IC is the same.

[0039] The scheme of the present application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of the various embodiments have their own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. Those skilled in the art should also be aware that the actions and modules involved in the specification are not necessarily required for the present application. In addition, it can be understood that the steps in the method of the embodiment of the present application can be adjusted in order, merged and deleted according to actual needs, and the modules in the device of the embodiment of the present application can be merged, divided and deleted according to actual needs.

[0040] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A circuit board tin printing structure, characterized in that: include: A PCB board, wherein the PCB board is provided with a through hole; A steel mesh layer is arranged on the PCB board, and a tin-printing hole is opened on the steel mesh layer, and the projection of the tin-printing hole on the PCB board does not overlap with the through hole.

2. The circuit board tin printing structure according to claim 1, characterized in that: The thickness of the steel mesh layer is in the range of 0.12 mm.

3. The circuit board tin printing structure according to claim 1, characterized in that: The horizontal distance from the through hole to the solder printing hole ranges from 0.25 mm to 0.45 mm.

4. The circuit board tin printing structure according to claim 1, characterized in that: The cross-sectional structure of the tin-printing hole is a rectangular cross-sectional structure.

5. The circuit board tin printing structure according to claim 1, characterized in that: The cross-sectional structure of the tin-printing hole is a circular cross-sectional structure.

6. The circuit board tin printing structure according to claim 5, characterized in that: The diameter of the tin-printing hole ranges from 0.5 mm to 0.6 mm.

7. The circuit board tin printing structure according to claim 6, characterized in that: The cross-sectional structure of the through hole is a circular cross-sectional structure.

8. The circuit board tin printing structure according to claim 7, characterized in that: The diameter of the tin-printing hole is larger than the diameter of the through hole.

9. The circuit board tin printing structure according to claim 1, characterized in that: The steel mesh layer is provided with a plurality of tin-printing holes, and the PCB board is provided with a plurality of through holes, wherein the projection of each tin-printing hole on the PCB board does not overlap with each through hole.

10. The circuit board tin printing structure according to claim 9, characterized in that: The interval between every two adjacent solder holes is the same.

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