Precision ball planting electroformed steel mesh

Abstract

The utility model discloses a precision ball-planting electroformed steel net, including net board and mesh, at least cover a membrane layer on the electroformed template of net board, the mesh includes the guide hole and electroformed mesh hole with position corresponding, and the aperture of guide hole is greater than the aperture of electroformed mesh hole, and the hole wall of guide hole is provided with the inclined guide boss. The hole wall of guide hole is provided with at least two guide bosses, and the inclination angle alpha of guide boss is 15-25 DEG. The guide surface of guide boss is inclined plane, and the inclined plane extends from the upper end of membrane layer to the upper end of corresponding electroformed mesh hole. Two guide bosses are oppositely arranged on the hole wall of guide hole, and the opposite two guide bosses are located on the same diameter. The guide surface of guide boss is inclined plane, and the inclined plane extends from the upper end of surface side membrane layer to the upper end of corresponding electroformed mesh hole through intermediate membrane layer. The electroformed steel net can not only adapt to the ball diameter requirement of different implanted solder balls, but also accurately position the solder ball implantation position.

Description

Technical Field

[0001] This utility model relates to wafer packaging templates in the chip manufacturing process, and more particularly to template steel mesh structures in wafer packaging templates. Background Technology

[0002] In chip manufacturing, the wafer packaging template is a crucial mold used to create advanced packaging structures to achieve high chip integration, playing an irreplaceable role. The gold-solder ball placement on the packaging template is one of its key functions, directly determining the stability of the connection between the chip and the circuit board. Traditional packaging template stencils suffer from low aperture precision and rough hole walls, leading to uneven control of solder amount and ball placement, resulting in problems such as cold solder joints and bridging, with a solder joint yield of less than 90%. Electroformed stencils, on the other hand, use an electroforming process to continuously deposit metal ions under an electric field to create a metal template with a high-precision three-dimensional structure. Its dimensional accuracy can reach the micron or even nanometer level. Electroformed stencils not only enable the manufacture of complex structures with high precision but also exhibit excellent consistency and repeatability.

[0003] In chip repair and manufacturing, ball repositioning refers to the solder ball reloading process in Ball Grid Array (BGA) packaging, used to repair or package chips. Its core is the precise placement of solder balls, and the printed circuit board (PCB) is a crucial tool for this process, allowing for precise positioning of the solder balls onto the chip pads. While electroformed stencil substrates offer several advantages, they are also ultra-thin metal plates. Increasing the thickness of the PCB substrate, while technically feasible for production efficiency, significantly extends the manufacturing cycle and increases costs. Furthermore, the large size ratio between the ultra-thin PCB and the solder ball prevents accurate embedding and positioning of the solder balls within the mesh openings, directly impacting solder joint yield and chip packaging quality. Additionally, while PCB repositioning aims to accurately embed one solder ball in each mesh opening, the mesh opening diameter is often similar to the solder ball diameter, reducing the solder ball embedding rate and increasing the likelihood of solder balls bypassing or overshooting the mesh openings, leading to missed solder balls. Utility Model Content

[0004] In view of the above-mentioned shortcomings of the existing technology, the technical problem to be solved by this utility model is to provide a precision ball-embedded electroformed steel mesh that can not only adapt to the ball diameter requirements of different implanted welding balls, but also accurately position the welding ball implantation position.

[0005] To solve the above-mentioned technical problems, the present invention provides a precision ball-planting electroformed steel mesh, comprising a mesh plate and mesh holes disposed on the mesh plate. The mesh plate includes an electroforming template, on which at least one film layer is covered. The mesh holes include guide holes and electroformed mesh holes with corresponding positions. The diameter of the guide holes is larger than the diameter of the electroformed mesh holes. Inclined guide ribs are provided on the hole walls of the guide holes.

[0006] In the above structure, the encapsulation template stencil uses an electroformed metal substrate, which has high mechanical strength, greatly increasing the frequency of physical contact with the lithography machine and significantly improving the positional and dimensional accuracy of the mesh. The film coating on the electroformed template not only effectively reduces the thickness of the electroformed substrate and lowers the cost of the printed encapsulation template, but also allows for the insertion of solder balls with different diameters by adjusting and replacing the two side films of different thicknesses, thus increasing the template's applicability. The film coating on the electroformed substrate also provides effective protection, extending its service life and enhancing its resistance to lithography etching solution corrosion and high-frequency wear. Because the guide hole diameter is larger than the electroformed mesh diameter, and two opposing guide ribs are provided on the guide hole walls, the solder balls can be accurately guided into the mesh openings of the stencil. Furthermore, the rib structure reduces the frictional resistance of the solder ball insertion, preventing solder ball leakage. Furthermore, since the guide ribs on the guide hole wall are set at an angle, the angled guide ribs are more conducive to the insertion and rotation of the welding ball, and can more accurately guide the welding ball into the mesh of the steel mesh, avoiding the welding ball from getting stuck at the edge, and also allowing the welding ball to move along the guide surface of the rib.

[0007] Furthermore, at least two guide ribs are provided on the wall of the guide hole, with an inclination angle α of 15°–25°. The guiding surface of the guide rib is an inclined plane, extending from the upper end of the film layer to the upper end of the corresponding electroformed mesh. This structure can accurately guide the welding ball into the steel mesh mesh, avoiding missed welding ball insertion.

[0008] Furthermore, the guide ribs are arranged in pairs opposite each other on the wall of the guide hole, with the two opposite guide ribs located on the same diameter. Two to four guide ribs are provided on the wall of the guide hole. Both the guide hole and the electroformed mesh are circular holes, and the center lines of the corresponding guide hole and electroformed mesh are on the same straight line. This facilitates the precise positioning and implantation of the solder ball.

[0009] Furthermore, the membrane layer includes a face-side membrane layer and an intermediate membrane layer, with the intermediate membrane layer and the face-side membrane layer sequentially coated on the electroforming template; the guide hole is disposed through the face-side membrane layer and the intermediate membrane layer. The guide surface of the guide rib is an inclined surface, which extends from the upper end of the face-side membrane layer through the intermediate membrane layer to the upper end of the corresponding electroforming mesh. This not only adapts to the implantation requirements of solder balls of different diameters, but also ensures precise and reliable solder ball implantation.

[0010] Furthermore, the electroforming template is an electroformed nickel mesh, and the film layer is formed by bonding a polymer film. This provides advantages such as high mechanical strength and resistance to wear and tear. Attached Figure Description

[0011] The present invention, a precision ball-planting electroformed steel mesh, will be further described below with reference to the accompanying drawings and specific embodiments.

[0012] Figure 1 This is a schematic diagram of a specific embodiment of the precision ball-planted electroforming steel mesh of this utility model;

[0013] Figure 2 This is a magnified schematic diagram of the mesh structure in type 1;

[0014] Figure 3 yes Figure 2 Cross-sectional structural diagram of section A-A;

[0015] Figure 4 yes Figure 2 Cross-sectional structural diagram of section B-B.

[0016] In the figure, 1—mesh plate, 11—side film layer, 12—intermediate film layer, 13—electroforming template, 2—mesh hole, 21—guide hole, 22—electroforming mesh hole, 3—mold hole, 4—guide rib. Detailed Implementation

[0017] like Figure 1 The precision electroformed steel mesh shown includes a mesh plate 1, on which several through-holes 3 and mesh holes 2 are provided. The through-holes 3 are used to insert electronic component patches, and the mesh holes 2 are used to insert solder balls, such as solder balls.

[0018] The stencil 1 includes an electroforming template 13, which is an electroformed nickel mesh produced by an electroforming process. An intermediate film layer 12 is adhered to the face side of the electroforming template 13, and a face-side film layer 11 is adhered to the upper side of the intermediate film layer 12 in the same manner. The face-side film layer 11 and the intermediate film layer 12 constitute a film layer. Alternatively, the film layer can be a single layer. Both the face-side film layer 11 and the intermediate film layer 12 are made of polyimide film (PI film); PI film has excellent corrosion and wear resistance, and also high mechanical strength.

[0019] Each mesh 2 on the screen plate 1 is formed by stacking guide holes 21 and electroformed mesh 22 that are corresponding to each other. The guide holes 21 are located on the side film layer 11 and the middle film layer 12 that are pasted together, while the electroformed mesh 22 is located on the electroformed template 13.

[0020] like Figure 2 , Figure 3 and Figure 4 As shown, both the guide hole 21 and the electroformed mesh 22 constituting the mesh 2 are circular through holes, but the diameter of the guide hole 21 is larger than that of the electroformed mesh 22. Furthermore, the center lines of the guide hole 21 and the electroformed mesh 22 are located on the same straight line.

[0021] Four inclined guide ribs 4 are provided on the wall of the guide hole 21. The four guide ribs 4 correspond to each other in pairs, that is, two opposite guide ribs 4 are located on the same diameter. The inclination angle α of the guide ribs 4 relative to the center line of the hole (the included angle formed by the spatial intersection) is 20°; this inclination angle is preferably selected as α = 15°-25°. Of course, two or three guide ribs 4 can also be provided on the wall of the guide hole 21.

[0022] The guide rib 4 has a sloping surface facing the center line of the hole. This sloping surface slopes downward from the upper end of the guide hole 21 and extends through the intermediate film layer 22 to the upper end of the corresponding electroforming mesh 13. This guide rib 4 can guide the solder ball to roll accurately into the electroforming mesh 22, so that the solder ball is accurately implanted into the electroforming mesh 22.

[0023] The preferred exemplary embodiments of the present invention have been described above by way of illustration only. However, those skilled in the art can make various modifications and improvements to the described embodiments without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A precision ball-embedded electroformed steel mesh, comprising a mesh plate (1) and mesh openings (2) disposed on the mesh plate (1), characterized in that: The mesh plate (1) includes an electroforming template (13), on which at least one film layer is covered; the mesh (2) includes guide holes (21) and electroforming mesh (22) with corresponding positions, the diameter of the guide holes (21) is larger than the diameter of the electroforming mesh (22); the guide holes (21) are provided with inclined guide ribs (4) on the hole wall.

2. The precision ball-embedded electroformed steel mesh according to claim 1, characterized in that: At least two guide ribs (4) are provided on the wall of the guide hole (21), and the inclination angle of the guide ribs (4) is 15°-25°.

3. The precision ball-embedded electroformed steel mesh according to claim 1 or 2, characterized in that: The guiding surface of the guide rib (4) is an inclined surface, which extends from the upper end of the film layer to the upper end of the corresponding electroforming mesh (22).

4. The precision ball-embedded electroformed steel mesh according to claim 1, characterized in that: The guide ribs (4) are arranged in pairs opposite each other on the wall of the guide hole (21), and the two opposite guide ribs (4) are located on the same diameter.

5. The precision ball-embedded electroformed steel mesh according to claim 4, characterized in that: The guide hole (21) has 2-4 guide ribs (4) on its wall.

6. The precision ball-embedded electroformed steel mesh according to claim 1, characterized in that: The guide hole (21) and the electroformed mesh (22) are both circular holes, and the center lines of the corresponding guide hole (21) and electroformed mesh (22) are on the same straight line.

7. The precision ball-embedded electroformed steel mesh according to claim 1, characterized in that: The film layer includes a face-side film layer (11) and an intermediate film layer (12), and the electroforming template (13) is sequentially covered with the intermediate film layer (12) and the face-side film layer (11); the guide hole (21) is disposed through the face-side film layer (11) and the intermediate film layer (12).

8. The precision ball-embedded electroformed steel mesh according to claim 7, characterized in that: The guiding surface of the guide rib (4) is an inclined surface, which extends from the upper end of the side film layer (11) through the middle film layer (12) to the upper end of the corresponding electroformed mesh (22).

9. The precision ball-embedded electroformed steel mesh according to claim 1, characterized in that: The electroforming template (13) is an electroformed nickel mesh, and the film layer is made of a polymer film.

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