Quad flat no-lead (QFN) packaging bonding pad, printed circuit board (PCB) and electronic equipment

Abstract

The embodiment of the utility model discloses a QFN (Quad Flat No-lead) packaging bonding pad, a PCB (Printed Circuit Board) and electronic equipment, which are used for solving the problems that after a through hole of the existing QFN packaging bonding pad is blocked by green oil, the green oil has a certain proportion and does not completely block the through hole, so that solder paste is melted and permeates into the back surface of the PCB through the through hole in the welding process, the IQC (Inter-Quality Check) inspection is poor, and the quality of the PCB is influenced. And short circuit of the PCB is caused. The welding pad comprises a welding pad main body, a plurality of steel meshes and a plurality of through holes are arranged on the welding pad main body, the through holes are plugged by green oil, the welding pad is characterized in that the steel meshes are arranged in gaps among the through holes, and safe distances are reserved between the edges of the steel meshes and the edges of the through holes.

Description

Technical Field

[0001] The utility model relates to the technical field of QFN packaging, in particular to a QFN packaging pad, a PCB board and an electronic device. Background Art

[0002] With the development of the electronic production industry, SMT (Surface Mount Technology) is also constantly improving. QFN is a surface mount package. Due to its small size, light weight, outstanding electrical and thermal properties, and low development cost, its application is growing rapidly.

[0003] QFN packaged chips are generally soldered to the QFN pads of the PCB by tin soldering. At present, the commonly used QFN pads include a pad body, on which a steel mesh for applying solder paste and a through hole for heat dissipation are provided. The through hole runs through the pad body and the PCB board. The through hole is generally sealed by the green oil plugging process. Because a certain proportion of the green oil plugging holes does not reach a completely blocked state, the solder paste on the pad body will melt during the SMT furnace, and the flowing solder paste will penetrate through the through hole to the back of the PCB board, resulting in poor IQC inspection and technical problems such as PCB short circuit.

[0004] Therefore, finding a technical solution that can solve the above technical problems has become an important topic studied by technical personnel in this field. Utility Model Content

[0005] The utility model discloses a QFN package pad, a PCB board and an electronic device, which are used to solve the technical problem that after the through hole of the existing QFN package pad is blocked with green oil, a certain proportion of the green oil fails to completely block the through hole, resulting in the melting of solder paste and penetrating through the through hole to the back of the PCB board during the welding process, resulting in poor IQC inspection and causing a PCB short circuit.

[0006] An embodiment of the utility model provides a QFN package pad, including a pad body, on which a plurality of steel meshes and a plurality of through holes are arranged, wherein the through holes are blocked by plugging with green oil, the steel meshes are located in the gaps between the plurality of through holes, and a safety distance is reserved between the edge of the steel mesh and the edge of the through hole.

[0007] Optionally, the safety distance is greater than 0.3 mm.

[0008] Optionally, the total area of ​​the plurality of steel meshes accounts for more than 50% of the area of ​​the pad body.

[0009] Optionally, a plurality of the through holes are arranged in a matrix on the pad body.

[0010] Optionally, the plurality of through holes are arranged on the pad body in a 3*3 matrix.

[0011] Optionally, a plurality of through-hole mounting 4*4 matrices are arranged on the pad body.

[0012] The utility model embodiment provides a PCB board, comprising the above-mentioned QFN package pad;

[0013] The packaging pad is fixedly arranged on the surface of the PCB board.

[0014] An embodiment of the utility model provides an electronic device, comprising the above-mentioned PCB board.

[0015] It can be seen from the above technical solutions that the embodiments of the utility model have the following advantages:

[0016] In the QFN package pad of this embodiment, a plurality of steel meshes and a plurality of through holes are arranged on the pad body, the steel meshes are located in the gaps between the plurality of through holes, and a safety distance is reserved between the edge of the steel mesh and the edge of the through hole. Through the above design, when the SMT is passed through the furnace, since the steel mesh is at a certain safety distance from the through hole, the melted solder paste will not flow to the position of the through hole, thereby preventing the solder paste from penetrating to the back of the PCB board and avoiding the risk of short circuit on the PCB board. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of the structure of a QFN package pad provided by an embodiment of the utility model when through holes are installed in a 3*3 matrix arrangement;

[0019] Figure 2 A schematic diagram of the structure of a QFN package pad provided by an embodiment of the utility model when through holes are installed in a 4*4 matrix arrangement;

[0020] Illustration: pad body 1; through hole 2; steel mesh 3; safety distance d. DETAILED DESCRIPTION

[0021] The utility model discloses a QFN package pad, a PCB board and an electronic device, which are used to solve the technical problem that after the through hole of the existing QFN package pad is blocked with green oil, a certain proportion of the green oil fails to completely block the through hole, resulting in the melting of solder paste and penetrating through the through hole to the back of the PCB board during the welding process, resulting in poor IQC inspection and causing a PCB short circuit.

[0022] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0023] Please refer to Figure 1 and Figure 2 An embodiment of the utility model provides a QFN package pad, including a pad body 1, on which a plurality of steel meshes 3 and a plurality of through holes 2 are arranged, wherein the through holes 2 are blocked by green oil plugging, and the steel mesh 3 is located in the gap between the plurality of through holes 2, and a safety distance is reserved between the edge of the steel mesh 3 and the edge of the through hole 2.

[0024] In the QFN package pad of this embodiment, a plurality of steel meshes 3 and a plurality of through holes 2 are arranged on the pad body 1, and the steel meshes 3 are located in the gaps between the plurality of through holes 2, and a safety distance is reserved between the edge of the steel mesh 3 and the edge of the through hole 2. With the above design, during the SMT furnace, since the steel mesh 3 is at a certain safety distance from the through hole 2, the melted solder paste will not flow to the position of the through hole 2, thereby preventing the solder paste from penetrating to the back of the PCB board and avoiding the risk of short circuit on the PCB board.

[0025] Furthermore, the safety distance in this embodiment is greater than 0.3 mm.

[0026] It should be noted that, through the above design, the safety distance reserved between the edge of the steel mesh 3 and the edge of the through hole 2 is greater than 0.3 mm, so that the solder paste on the steel mesh 3 will not flow to the position of the through hole 2 after melting during the SMT furnace process, avoiding the risk of solder paste penetrating to the back of the PCB board and causing a short circuit on the PCB board.

[0027] Furthermore, the total area of ​​the plurality of steel meshes 3 accounts for more than 50% of the area of ​​the pad body 1 .

[0028] It should be noted that since the main function of the steel mesh 3 is to apply solder paste, the above design can ensure the amount of solder paste used, ensure the stability of welding, and prevent the melted solder paste from flowing into the position of the through hole 2, without causing any adverse effects on the layout and wiring on the back of the PCB board, such as the risk of short circuit.

[0029] Furthermore, the plurality of through holes 2 are arranged in a matrix on the pad body 1 .

[0030] Specifically, when the pad body 1 is of a conventional size of 4*4mm to 6*6mm, as Figure 1 As shown, a plurality of through holes 2 are arranged in a 3*3 matrix on the pad body 1. In this case, the number of steel meshes 3 is 4, and the 4 steel meshes 3 are evenly distributed in the 3*3 through hole 2 matrix.

[0031] When the size of the pad body 1 exceeds 6*6mm, such as Figure 2 As shown, a plurality of the through holes 2 are installed in a 4*4 matrix and arranged on the pad body 1. In this case, the number of the steel meshes 3 is 9, and the 9 steel meshes 3 are evenly distributed in the 4*4 through hole 2 matrix.

[0032] In addition, the arrangement of the plurality of through holes 2 may also be circular, etc., which is not limited in this embodiment, and designers may select a suitable arrangement according to actual conditions.

[0033] To sum up, the QFN package pad in this embodiment can use a lower-cost green oil plugging process to seal the through hole 2, while avoiding the risk of poor IQC detection and PCB short circuit caused by the solder paste penetrating into the back of the PCB through the through hole 2 on the QFN pad during SMT furnace.

[0034] See also Figure 1 and Figure 2 , the embodiment of the utility model provides a PCB board, including the above-mentioned QFN package pad;

[0035] The packaging pad is fixedly arranged on the surface of the PCB board.

[0036] It should be noted that, through the above design, a plurality of steel meshes 3 and a plurality of through holes 2 are provided on the pad body 1, and the steel meshes 3 are located in the gaps between the plurality of through holes 2, and a safety distance is reserved between the edge of the steel mesh 3 and the edge of the through hole 2. Through the above design, when the SMT is passed through the furnace, since the steel mesh 3 is at a certain safety distance from the through hole 2, the melted solder paste will not flow to the position of the through hole 2, thereby preventing the solder paste from penetrating to the back of the PCB board and avoiding the risk of short circuit on the PCB board.

[0037] See also Figure 1 and Figure 2 An embodiment of the utility model provides an electronic device, including the above-mentioned PCB board.

[0038] Specifically, the above-mentioned electronic device may be a notebook computer, a server, a tablet computer, a smart phone, etc.

[0039] The above is a detailed introduction to a QFN package pad, a PCB board and an electronic device provided by the utility model. For a person skilled in the art, according to the idea of ​​the embodiment of the utility model, there may be changes in the specific implementation method and the scope of application. In summary, the content of this specification should not be understood as a limitation on the utility model.

Claims

1. A QFN package pad, comprising a pad body (1), wherein the pad body (1) is provided with a plurality of steel meshes (3) and a plurality of through holes (2), wherein the through holes (2) are blocked by plugging with green oil, characterized in that: The steel mesh (3) is located in the gaps between the plurality of through holes (2), and a safety distance is reserved between the edge of the steel mesh (3) and the edge of the through hole (2).

2. The QFN package pad according to claim 1, characterized in that: The safety distance is greater than 0.3 mm.

3. The QFN package pad according to claim 1, characterized in that: The total area of ​​the plurality of steel meshes (3) accounts for more than 50% of the area of ​​the pad body (1).

4. The QFN package pad according to claim 1, characterized in that: The plurality of through holes (2) are arranged in a matrix on the pad body (1).

5. The QFN package pad according to claim 4, characterized in that: The plurality of through holes (2) are arranged on the pad body (1) in a 3*3 matrix.

6. The QFN package pad according to claim 4, characterized in that: A plurality of the through holes (2) are arranged in a 4*4 matrix on the pad body (1).

7. A PCB board, characterized in that: A QFN package pad comprising any one of claims 1 to 6; The packaging pad is fixedly arranged on the surface of the PCB board.

8. An electronic device, characterized in that: Comprising the PCB board as claimed in claim 7.

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