PCB silver immersion plate welding ring circuit teardrop structure

Abstract

The utility model discloses a PCB electroless silver board welding ring circuit teardrop structure, and relates to the circuit board production field, the teardrop structure is symmetrically arranged between two adjacent welding rings, the two welding rings are connected through a wire, the teardrop structure is arranged on two sides of the wire, the teardrop structure comprises a wire connecting part and a teardrop part, the wire connecting part is connected with the teardrop part, and the teardrop part is connected with the wire connecting part. The tear dripping parts are arranged at the included angle position of the wire and the welding ring, the two ends of each tear dripping part are connected to the wire and the welding ring respectively, the wire connecting part is arranged on one side of the wire in parallel, the two ends of the wire connecting part are connected to the two tear dripping parts respectively, and the outer surfaces of the wire and the tear dripping structure are coated with anti-corrosion layers. And the circuit copper foil is prevented from being corroded by the galvanic effect in the silver melting production process to generate a thin neck phenomenon.

Description

Technical Field

[0001] This utility model relates to the field of circuit board manufacturing, and in particular to a teardrop structure for solder ring circuits on a PCB immersion silver board. Background Technology

[0002] Printed circuit boards (PCBs) are important electronic components, serving as the support for electronic components and the carrier for their electrical connections. PCBs undergo various surface treatments, the purpose of which is to improve solderability, corrosion resistance, conductivity, and protect the board from oxidation. The main functions are as follows: Promoting soldering: Improving solderability and ensuring strong solder joints. Promoting corrosion resistance: Enhancing corrosion resistance and extending the lifespan of the circuit board. Improving conductivity: Reducing resistance and improving signal transmission quality. Protecting the board: Preventing oxidation and moisture damage to the metal surface.

[0003] In the process of tin plating for PCB surface treatment, the Giovanni effect will occur at the connection between the solder ring and the circuit during the silver plating production process. This will cause the copper foil at the connection between the solder ring and the circuit to form a neck phenomenon due to corrosion.

[0004] Therefore, this utility model provides a teardrop structure for the solder ring circuit of a PCB immersion silver board to solve the problem of a thin neck phenomenon caused by the corrosion of copper foil at the connection between the solder ring and the circuit. The middle part of the conductor is protected to reduce the side corrosion in the middle of the conductor and ensure the integrity of the conductor. Utility Model Content

[0005] To achieve the above objectives, this utility model adopts the following technical solution: a teardrop structure for solder ring circuits on a PCB immersion silver board. The teardrop structure is symmetrically arranged between two adjacent solder rings, and the two solder rings are connected by a wire. The teardrop structure is arranged on both sides of the wire. Each teardrop structure includes a connecting part and a teardrop part. The teardrop part is located at the angle between the wire and the solder ring. The two ends of the teardrop part are respectively connected to the wire and the solder ring. The connecting part is arranged parallel to one side of the wire, and the two ends of the connecting part are respectively connected to the two teardrop parts. The surfaces of the wire and the teardrop structure away from the circuit board are coated with an anti-corrosion layer.

[0006] Preferably, the length direction of the teardrop portion is parallel to the center line of the conductor, L=o+x, where L is the length of the teardrop portion, o is the size of one side of the solder mask opening, and x is a constant value, 3mil≤x≤5mil.

[0007] Preferably, W ≥ 8 mil, where W is the width of the teardrop.

[0008] Preferably, D ≥ 8mil, where D is the conductor width. Teardrop structures are provided on both sides of all conductors with an outer layer trace width < 8mil (outer layer trace width in the datasheet) that are connected to the solder ring / SMT. Two teardrop structures protect the four included angles between the conductor and the solder ring.

[0009] Preferably, the teardrop portion is a copper foil in the shape of a right-angled triangle, and the two right-angled sides of the teardrop portion are respectively connected to the wire and the solder ring.

[0010] Preferably, the connecting portion is a long and narrow rectangle, and the two ends of the connecting portion are respectively located on the oblique sides of the two teardrop portions.

[0011] Preferably, the anti-corrosion layer is solder resist ink. The solder resist ink covers the circuit and the teardrop structure to protect the circuit. The teardrop width of the solder resist is designed with an ink cover to prevent the silver plating solution from corroding the circuit and solder ring.

[0012] Preferably, the connecting portion includes a carbon fiber mesh, an adhesive layer, and a copper foil. The carbon fiber mesh and the copper foil are bonded together by the adhesive layer, and the carbon fiber mesh is disposed inside the adhesive layer. The copper foil of the connecting portion is integrally formed and connected to the teardrop portion. Before and during lamination, the copper foil of the connecting portion is reinforced by the carbon fiber mesh to prevent breakage of the copper foil before lamination and to prevent cracking of the copper foil under pressure during lamination.

[0013] Preferably, the adhesive layer is an epoxy resin hot melt adhesive. The adhesive layer melts upon heating and flows to both sides under the pressure of pressing, ultimately encasing the copper foil of the connecting portion.

[0014] Preferably, the adhesive layer fills the space between the connecting portion and the wire.

[0015] The working principle of this invention is as follows: After the copper foil is stacked on the substrate, hot pressing melts the adhesive layer. The molten adhesive layer flows into and fills the gap between the connection part and the wire under pressure, protecting the part of the wire that is not covered with a teardrop. The teardrop part is located at the angle between the solder ring and the circuit connection.

[0016] The beneficial effects of this utility model are as follows: the connection between the welding ring and the circuit is optimized by adding a teardrop design. The teardrop part protects the connection between the welding ring and the circuit, and the connecting part protects the middle part of the circuit, preventing the circuit from lateral corrosion caused by the corrosion of copper foil. Attached Figure Description

[0017] The accompanying drawings further illustrate the present invention, but the embodiments in the drawings do not constitute any limitation on the present invention.

[0018] Figure 1 This is a schematic diagram of a structure provided for an embodiment of the present utility model;

[0019] Figure 2 for Figure 1 A magnified view of part A in the middle;

[0020] Figure 3 A cross-sectional view provided for an embodiment of this utility model.

[0021] Figure reference numerals: 1: Solder ring; 2: Conductor; 3: Teardrop section; 4: Connection section; 5: Circuit board; 6: Anti-corrosion layer. Detailed Implementation

[0022] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0023] It should be noted that, in this invention, unless otherwise stated, when an element is referred to as "fixed to" or "set on" another element, it can be directly on the other element or an intervening element may also be present. When an element is referred to as "connected to" another element, it can be directly connected to the other element or an intervening element may also be present. "Outer" refers to the side away from the circuit board.

[0024] like Figures 1-3 As shown in the figure, an embodiment of the present invention provides a teardrop structure for the solder ring 1 of a PCB immersion silver board. The teardrop structure is symmetrically arranged between two adjacent solder rings 1, and the two solder rings 1 are connected by a wire 2. The teardrop structure is arranged on both sides of the wire 2. Each teardrop structure includes a connecting part 4 and a teardrop part 3. The teardrop part 3 is located at the angle between the wire 2 and the solder ring 1. The two ends of the teardrop part 3 are respectively connected to the wire 2 and the solder ring 1. The connecting part 4 is arranged parallel to one side of the wire 2. The two ends of the connecting part 4 are respectively connected to the two teardrop parts 3. The surfaces of the wire 2 and the teardrop structure away from the circuit board 5 are coated with an anti-corrosion layer 6.

[0025] The length direction of the teardrop part 3 is parallel to the center line of the conductor 2, L=o+x, where L is the length of the teardrop part 3, o is the size of one side of the solder mask opening, and x is a constant value, 3mil≤x≤5mil.

[0026] W≥8mil, where W is the width of the teardrop portion 3.

[0027] D≥8mil, where D is the line width of conductor 2. Teardrop structures are installed on both sides of all conductors 2 with an outer layer line width <8mil (outer layer trace width in the datasheet) that connect to solder ring 1 / SMT. Two teardrop structures protect the four included angles between conductor 2 and solder ring 1.

[0028] The teardrop part 3 is a copper foil in the shape of a right-angled triangle, and the two right-angled sides of the teardrop part 3 are respectively connected to the wire 2 and the solder ring 1.

[0029] The connecting part 4 is a long and narrow rectangle, and the two ends of the connecting part 4 are respectively located on the oblique sides of the two teardrop parts 3.

[0030] The anti-corrosion layer 6 is solder resist ink. The solder resist ink covers the circuitry and teardrop structure to protect the circuitry. The teardrop width of the solder resist is designed with an ink cover to prevent the silver plating solution from corroding the circuitry and solder ring 1.

[0031] The connecting part 4 includes a carbon fiber mesh, an adhesive layer, and a copper foil. The carbon fiber mesh and the copper foil are bonded together by the adhesive layer, and the carbon fiber mesh is disposed inside the adhesive layer. The copper foil of the connecting part 4 is integrally formed and connected to the teardrop part 3. Before and during lamination, the copper foil of the connecting part 4 is reinforced by the carbon fiber mesh to prevent breakage of the copper foil before lamination and to prevent cracking of the copper foil under pressure during lamination. In one embodiment, the two ends of the carbon fiber mesh are bonded to the center of the teardrop part 3 by the adhesive layer. In another embodiment, the carbon fiber mesh is replaced by a high-temperature resistant insulating fiber mesh, such as a glass fiber mesh. The width of the carbon fiber mesh is 1 mil to 2 mil smaller than the width of the copper foil of the connecting part 4.

[0032] The adhesive layer is an epoxy resin hot melt adhesive. When heated, the adhesive layer melts and flows to both sides under the pressure of the pressing process, ultimately encasing the copper foil of the connecting part 4.

[0033] The adhesive layer is filled between the connecting part 4 and the wire 2.

[0034] The technical features of the embodiments described above can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this utility model, and these should all be considered to be within the scope of this specification.

Claims

1. A teardrop structure for solder ring circuitry on a PCB immersion silver board, characterized in that: The teardrop structure is symmetrically arranged between two adjacent welding rings, and the two welding rings are connected by a wire. The teardrop structure is arranged on both sides of the wire. Each teardrop structure includes a connecting part and a teardrop part. The teardrop part is located at the angle between the wire and the welding ring. The two ends of the teardrop part are respectively connected to the wire and the welding ring. The connecting part is arranged parallel to one side of the wire. The two ends of the connecting part are respectively connected to the two teardrop parts. The outer surface of the wire and the teardrop structure are coated with an anti-corrosion layer.

2. The teardrop structure of the solder ring circuit on the PCB immersion silver board according to claim 1, characterized in that: The length direction of the teardrop is parallel to the center line of the conductor, L=o+x, where L is the length of the teardrop, o is the size of one side of the solder mask opening, and x is a constant value, 3mil≤x≤5mil.

3. The teardrop structure of the solder ring circuit on the PCB immersion silver board according to claim 1, characterized in that: W≥8mil, where W is the width of the teardrop.

4. The teardrop structure of the solder ring circuit on the PCB immersion silver board according to claim 1, characterized in that: D≥8mil, where D is the conductor linewidth.

5. The teardrop structure of the solder ring circuit on the PCB immersion silver board according to claim 1, characterized in that: The teardrop part is a right-angled triangle, and the two right-angled sides of the teardrop part are connected to the wire and the solder ring, respectively.

6. The teardrop structure of the solder ring circuit on the PCB immersion silver board according to claim 5, characterized in that: The connecting part is rectangular, and the two ends of the connecting part are respectively located on the hypotenuses of the two teardrops.

7. The teardrop structure of the solder ring circuit on the PCB immersion silver board according to claim 1, characterized in that: The anti-corrosion layer is solder resist ink.

8. The teardrop structure of the solder ring circuit on the PCB immersion silver board according to claim 1, characterized in that: The connecting part includes a carbon fiber mesh, an adhesive layer, and a copper foil, wherein the carbon fiber mesh and the copper foil are bonded together by the adhesive layer.

9. The teardrop structure of the solder ring circuit on the PCB immersion silver board according to claim 8, characterized in that: The adhesive layer is an epoxy resin hot melt adhesive.

10. The teardrop structure of the solder ring circuit on the PCB immersion silver board according to claim 9, characterized in that: The adhesive layer fills the space between the connecting portion and the conductor.

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