Circuit board and its pad structure

Abstract

This utility model discloses a circuit board and its pad structure. The pad structure is an elongated structure, and at least one of the long and short sides of the elongated structure has a notch structure. The notch structure is located at the midpoint or approximately the midpoint of its side. The notch structure is used for ball bonding and forming a moving channel for the solder ball. The solder ball moves to the back of the pad structure through the moving channel, and then forms a reliable solder connection with the motherboard on the back of the pad structure. The length of the long side is L, the width of the short side is W, and L / W ≥ 1.25.

Description

Technical Field

[0001] This utility model relates to the technical field of flexible circuit boards, specifically to a circuit board and its pad structure. Background Technology

[0002] With the rapid popularization of new energy vehicles, the demand for new energy battery packs is constantly increasing. The demand for FPCA (Plug-in Circuit Amplifier) ​​used for temperature and voltage acquisition of battery cells in new energy battery packs is also growing. To reduce the cost proportion of FPCA in new energy battery packs, a new FPCA technology route has been developed that involves soldering the main circuit board and branch circuit boards together.

[0003] However, existing soldering techniques require printing solder paste on the pads of the main circuit board, which can easily lead to unstable soldering reliability due to printing misalignment. In addition, improper temperature profile control in some soldering techniques can easily lead to functional problems such as cold solder joints and poor soldering. Some soldering techniques have high soldering temperatures and high equipment energy consumption. If the incoming material management is not good, the thermal shock to the branch boards and FPC body is large, which can easily lead to the delamination and explosion of the branch boards and FPC. Utility Model Content

[0004] In view of this, the present invention provides a circuit board and its pad structure to solve the problems of unstable reliability and poor temperature control caused by printing misalignment when the main circuit and branch circuit are soldered together in the prior art.

[0005] To achieve the above objectives, this utility model provides a circuit board pad structure, wherein the pad structure is an elongated structure, and at least one of the long and short sides of the elongated structure has a notch structure, the notch structure being located at the midpoint or approximately the midpoint of its respective side; the notch structure is used for ball bonding, forming a channel for the movement of the solder ball, which moves through the channel to the back of the pad structure, thereby forming a reliable solder connection with the motherboard on the back of the pad structure;

[0006] Wherein, the length of the longer side is L, the width of the shorter side is W, and L / W≥1.25.

[0007] Preferably, in the pad structure of the circuit board, the notch structure includes a first semicircular structure that penetrates the two long sides of the elongated structure and a second semicircular structure that penetrates one short side of the elongated structure.

[0008] Preferably, in the pad structure of the circuit board, the radius of the first semicircular structure is R2, the radius of the second semicircular structure is R1, L / 10≤R2≤L / 6, and W / 7≤R1≤W / 5.

[0009] Preferably, in the pad structure of the circuit board, the notch structure includes a first semicircular structure that passes through the two long sides of the elongated structure.

[0010] Preferably, in the pad structure of the circuit board, the radius of the first semicircular structure is R2, and L / 8≤R2≤L / 6.

[0011] Preferably, in the pad structure of the circuit board, the notch structure includes a second semicircular structure extending through a short side of the elongated structure.

[0012] Preferably, in the pad structure of the circuit board, the radius of the second semicircular structure is R1, and W / 6≤R1≤W / 4.

[0013] Preferably, in the pad structure of the circuit board, the notch structure includes a first rectangular or trapezoidal structure that passes through the two long sides of the elongated structure, and a second rectangular or trapezoidal structure that passes through one short side of the elongated structure.

[0014] Preferably, in the pad structure of the circuit board, the length of the first rectangular or trapezoidal structure along the length direction of the long side is W1, the width of the first rectangular or trapezoidal structure along the direction perpendicular to the long side is L1, the width of the second rectangular or trapezoidal structure along the width direction of the short side is W2, the length of the second rectangular or trapezoidal structure along the direction perpendicular to the width direction of the short side is L2, L / 8≤L1≤L / 6, L / 8≤L2≤L / 5, W / 8≤W1≤W, W / 6≤W2≤W / 4.

[0015] To achieve the above objectives, this utility model provides a circuit board, the circuit board comprising:

[0016] Motherboard, including main solder pads;

[0017] A branch board, including the aforementioned pad structure, wherein solder balls are inserted into the notch structure of the pad structure to solder the pad structure and the main pad together.

[0018] This utility model has at least the following beneficial effects:

[0019] This invention utilizes an elongated pad structure with at least one notch along its long and short sides. The notch is located at or approximately the midpoint of its respective side and is used for solder ball placement, forming a channel for the solder ball to move. The solder ball moves through this channel to the back of the pad structure, thus forming a reliable solder connection with the motherboard on the back of the pad structure. The length of the long side is L, and the width of the short side is W, with L / W ≥ 1.25. This design solves the problems of reliability instability and poor temperature control caused by printing misalignment when soldering main and branch circuits together in existing technologies.

[0020] Furthermore, by setting notches in the pad structure and combining them with ball-mounting welding technology, this invention can significantly reduce energy consumption and cost compared to other welding technologies, greatly improve operational efficiency, and enhance welding reliability.

[0021] Furthermore, this invention provides a specific notch structure on the solder pads of the branch board, and inserts solder balls through the notch structure. The molten solder balls weld the branch board and the main board together, which can achieve accurate and reliable welding, significantly reduce energy consumption, and significantly improve operating efficiency. Attached Figure Description

[0022] The features and advantages of this utility model will be more clearly understood by referring to the accompanying drawings. The drawings are schematic and should not be construed as limiting the utility model in any way. In the drawings:

[0023] Figure 1 This diagram illustrates an embodiment of the branch plate provided by the present invention.

[0024] Figure 2 It indicates Figure 1 A schematic diagram of the pad structure in the first embodiment;

[0025] Figure 3 It indicates Figure 1 A schematic diagram of the pad structure in the second embodiment;

[0026] Figure 4 It indicates Figure 1 A schematic diagram of the pad structure in the third embodiment;

[0027] Figure 5 It indicates Figure 1 A schematic diagram of the pad structure in the fourth embodiment;

[0028] Figure 6 It indicates Figure 1 A schematic diagram of the pad structure in the fifth embodiment;

[0029] Figure 7This diagram illustrates an embodiment of the motherboard provided by the present invention.

[0030] Figure 8 This schematic diagram illustrates an embodiment in which the motherboard and branch board are fixed together according to this utility model.

[0031] Figure 9 It indicates Figure 8 A schematic diagram showing the use of a pressure plate when soldering the motherboard and branch boards.

[0032] The labels in the attached figures are explained as follows:

[0033] 1-Branch board, 11-Pad structure, 111-Long side, 112-Short side, 113-Notch structure, 113a-First semicircular structure, 113b-Second semicircular structure, 113c-First rectangular or trapezoidal structure, 113d-Second rectangular or trapezoidal structure, 12-Positioning hole, 2-Main board, 21-Main pad, 22-Mating hole, 3-Pressure plate, 4-Carrier. Detailed Implementation

[0034] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. The present utility model will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this utility model can be combined with each other.

[0035] In this embodiment of the invention, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0037] In this embodiment of the invention, the term "multiple" refers to two or more, and other quantifiers are similar.

[0038] In this utility model, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the various embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are provided in the various embodiments of this utility model to facilitate a better understanding of the invention. However, the technical solutions claimed by this utility model can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this utility model. The various embodiments can be combined with and referenced by each other without contradiction.

[0040] This utility model provides a solder pad structure for a circuit board, such as... Figures 1 to 6 As shown, the pad structure 11 is an elongated structure. At least one of the long side 111 and the short side 112 of the elongated structure is provided with a notch structure 113. The notch structure 113 is located at the midpoint or approximately the midpoint of its side. The notch structure 113 is used for ball bonding and forms a moving channel for the solder ball. The solder ball moves to the back of the pad structure 11 through the moving channel, and then forms a reliable solder connection with the motherboard 2 on the back of the pad structure 11. The length of the long side 111 is L, the width of the short side 112 is W, and L / W ≥ 1.25.

[0041] This invention utilizes an elongated pad structure 11. At least one of the long side 111 and short side 112 of the elongated structure has a notch structure 113. The notch structure 113 is located at or approximately at the midpoint of its respective side. The notch structure 113 is used for ball bonding, forming a channel for the solder ball to move. The solder ball moves through this channel to the back of the pad structure 11, thereby forming a reliable solder connection with the motherboard 2 on the back of the pad structure 11. The length of the long side 111 is L, and the width of the short side 112 is W, where L / W ≥ 1.25. This solves the problems of reliability instability and poor temperature control caused by printing misalignment when main circuits and branch circuits are soldered together in the prior art.

[0042] Furthermore, by setting notch positions in the pad structure 11 and combining it with ball-mounting welding technology, this invention can significantly reduce energy consumption and cost compared to other welding technologies, greatly improve operational efficiency, and achieve better welding reliability.

[0043] Furthermore, this utility model provides a specific notch structure 113 on the solder pads of the branch board 1, and inserts solder balls from the notch structure 113. The molten solder balls weld the branch board 1 and the main board 2 together. On the one hand, it can achieve accurate and reliable welding, significantly reduce energy consumption, and significantly improve operating efficiency.

[0044] The notch should be located at or approximately at the midpoint of the edge to achieve the best fixation effect after inserting solder balls at the notch. The solder balls can be, but are not limited to, solder balls.

[0045] It should be noted that in this utility model, the length of the short side 112 is less than the length of the long side 111.

[0046] Example 1

[0047] Figure 2 It indicates Figure 1 A schematic diagram of the middle pad structure 11 in the first embodiment. (See diagram below.) Figure 2 As shown, the notch structure 113 includes a first semicircular structure 113a that passes through the two long sides 111 of the elongated structure, and a second semicircular structure 113b that passes through a short side 112 of the elongated structure. Typically, one short side 112 of the pad structure 11 is used to connect circuits, and the second semicircular structure 113b needs to be placed on the other short side 112 opposite to the short side 112 that connects the circuits.

[0048] The radius of the first semicircular structure 113a is R2, the radius of the second semicircular structure 113b is R1, L / 10≤R2≤L / 6, W / 7≤R1≤W / 5.

[0049] If R2 is too large, it will affect the size of the remaining part of the side where the first semicircular structure 113a is located, making the pad structure 11 prone to breakage and affecting the overall strength; if R2 is too small, the welding area will be too small, resulting in insufficient welding strength.

[0050] Similarly, if R1 is too large, it will affect the size of the remaining part of the side where the second semicircle structure 113b is located, making the pad structure 11 prone to breakage and affecting the overall strength; if R1 is too small, the welding area will be too small, resulting in insufficient welding strength.

[0051] Example 2

[0052] Figure 3 It indicates Figure 1 A schematic diagram of the middle pad structure 11 in the second embodiment. (See diagram below.) Figure 3 As shown, the notch structure 113 includes a first semicircular structure 113a that passes through the two long sides 111 of the elongated structure. The radius of the first semicircular structure 113a is R2, and L / 8 ≤ R2 ≤ L / 6.

[0053] If R2 is too large, it will affect the size of the remaining part of the side where the first semicircular structure 113a is located, making the pad structure 11 prone to breakage and affecting the overall strength; if R2 is too small, the welding area will be too small, resulting in insufficient welding strength.

[0054] Example 3

[0055] Figure 4 It indicates Figure 1 A schematic diagram of the middle pad structure 11 in the third embodiment. (See diagram below.) Figure 4 As shown, the notch structure 113 includes a second semicircular structure 113b extending through a short side 112 of the elongated structure. The radius of the second semicircular structure 113b is R1, and W / 6 ≤ R1 ≤ W / 4.

[0056] If R1 is too large, it will affect the size of the remaining part of the side where the second semicircular structure 113b is located, making the pad structure 11 prone to breakage and affecting the overall strength; if R1 is too small, the welding area will be too small, resulting in insufficient welding strength.

[0057] Example 4

[0058] Figure 5 It indicates Figure 1 A schematic diagram of the middle pad structure 11 in the fourth embodiment; Figure 6 It indicates Figure 1 A schematic diagram of the middle pad structure 11 in the fifth embodiment. (See diagram below.) Figure 5 and Figure 6 As shown, the notch structure 113 includes a first rectangular or trapezoidal structure 113c that passes through the two long sides 111 of the elongated structure, and a second rectangular or trapezoidal structure 113d that passes through the short side 112 of the elongated structure. The length of the first rectangular or trapezoidal structure 113c along the length direction of the long side 111 is W1, and the width of the first rectangular or trapezoidal structure 113c along the direction perpendicular to the long side 111 is L1. The width of the second rectangular or trapezoidal structure 113d along the width direction of the short side 112 is W2, and the length of the second rectangular or trapezoidal structure 113d along the direction perpendicular to the width direction of the short side 112 is L2. L / 8≤L1≤L / 6, L / 8≤L2≤L / 5, W / 8≤W1≤W, W / 6≤W2≤W / 4.

[0059] If L1 is too large, it will affect the size of the remaining part of the short side 112 of the elongated structure, making the pad structure 11 prone to breakage and affecting the overall strength; if L1 is too small, the welding area will be too small, resulting in insufficient welding strength.

[0060] If L2 is too large, it will affect the size of the remaining part of the long side 111 of the elongated structure, making the pad structure 11 prone to breakage and affecting the overall strength; if L2 is too small, the welding area will be too small, resulting in insufficient welding strength.

[0061] If W1 is too large, it will affect the size of the remaining part of the long side 111 of the elongated structure, making the pad structure 11 prone to breakage and affecting the overall strength; if W1 is too small, the welding area will be too small, resulting in insufficient welding strength.

[0062] If W2 is too large, it will affect the size of the remaining part of the short side 112 of the elongated structure, making the pad structure 11 prone to breakage and affecting the overall strength; if W1 is too small, the welding area will be too small, resulting in insufficient welding strength.

[0063] This utility model also provides a circuit board, which includes a main board 2 and a branch board 1. The main board 2 includes a main pad 21; the branch board 1 includes the aforementioned pad structure 11, and solder balls are inserted into the notch structure 113 of the pad structure 11 to solder the pad structure 11 and the main pad 21 together. This circuit board includes an embodiment of the aforementioned pad structure 11; the beneficial effects of the aforementioned pad structure 11 can also be applied to this circuit board. Similarly, the aforementioned pad structure 11 includes an embodiment of this circuit board, and the beneficial effects of this circuit board can also be applied to the aforementioned pad structure 11.

[0064] (1) Secure motherboard 2. For example... Figure 7 and Figure 8 As shown, the motherboard 2 is fixed on the carrier 4 and kept flat. The surface of the motherboard 2 can be treated with an organic solderability protectant (OSP) or electroless gold plating. When electroless gold plating is performed on the motherboard 2, the gold thickness of the immersion gold plating is >0.05μm, and the nickel thickness of the electroless nickel plating is 3-7μm.

[0065] One or more main solder pads 21 can be set on the motherboard 2. The specific number can be determined according to the number of branch boards 1 that need to be soldered, and can be determined according to actual needs.

[0066] (2) Mounting Branch Board 1. Align the pad structure 11 of Branch Board 1 with the main pad 21 of Main Board 2 to prepare for subsequent ball mounting. Specifically, during mounting, the positioning holes 12 of Branch Board 1 and the mating holes 22 of Main Board 2 can be aligned and fixed to achieve positioning.

[0067] (3) Cover plate 3. The cover plate is fixed on the branch plate 1 to prevent the branch plate 1 from moving during the subsequent implantation of solder balls.

[0068] (4) Ball placement and soldering. Using a ball placement device, solder balls (e.g., tin balls) are inserted between the main board 2 and the branch board 1 through the notch structure 113, thereby achieving the fixation and electrical connection between the branch board 1 and the main board 2. The size of the solder balls can be determined according to the size of the notch structure 113, for example, the diameter of the notch structure 113 + 0.2 mm ≤ the diameter of the solder balls ≤ the diameter of the notch structure 113 + 0.8 mm.

[0069] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A land structure of a wiring board, characterized by comprising: The pad structure is an elongated structure, and at least one of the long and short sides of the elongated structure has a notch structure. The notch structure is located at the midpoint or approximately the midpoint of its side. The notch structure is used for ball bonding and forms a channel for the ball to move. The ball moves through the channel to the back of the pad structure and then forms a reliable solder connection with the motherboard on the back of the pad structure. Wherein, the length of the longer side is L, the width of the shorter side is W, and L / W≥1.

25.

2. The land structure of a circuit board according to claim 1, wherein The notch structure includes a first semicircular structure that penetrates the two long sides of the elongated structure, and a second semicircular structure that penetrates one short side of the elongated structure.

3. The land structure of a circuit board according to claim 2, wherein The radius of the first semicircular structure is R2, the radius of the second semicircular structure is R1, L / 10≤R2≤L / 6, W / 7≤R1≤W / 5.

4. The land structure of a circuit board according to claim 1, wherein The notch structure includes a first semicircular structure that passes through the two long sides of the elongated structure.

5. The land structure of a circuit board according to claim 4, wherein The radius of the first semicircular structure is R2, and L / 8≤R2≤L / 6.

6. The land structure of a circuit board according to claim 1, wherein The notch structure includes a second semicircular structure that extends through a short side of the elongated structure.

7. The land structure of a circuit board according to Claim 6, wherein The radius of the second semicircular structure is R1, and W / 6≤R1≤W / 4.

8. The land structure of a circuit board according to Claim 1, wherein The notch structure includes a first rectangular or trapezoidal structure that passes through the two long sides of the elongated structure, and a second rectangular or trapezoidal structure that passes through one short side of the elongated structure.

9. The land structure of a circuit board according to Claim 8, wherein The length of the first rectangular or trapezoidal structure along the length direction of the long side is W1, the width of the first rectangular or trapezoidal structure along the direction perpendicular to the long side is L1, the width of the second rectangular or trapezoidal structure along the width direction of the short side is W2, the length of the second rectangular or trapezoidal structure along the direction perpendicular to the width direction of the short side is L2, L / 8≤L1≤L / 6, L / 8≤L2≤L / 5, W / 8≤W1≤W, W / 6≤W2≤W / 4.

10. A circuit board, characterized in that, include: Motherboard, including main solder pads; A branch board, comprising a pad structure as described in any one of claims 1 to 9, wherein solder balls are inserted into a notch structure of the pad structure to solder the pad structure and the main pad together.

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