Thick copper wire bonding structure

Abstract

The utility model discloses a thick copper wire bonding structure which comprises a substrate, the substrate is arranged at the bottommost layer, four groups of bonding pads are arranged on the substrate, the bonding pads are distributed on two sides of the substrate in pairs, the substrate is sequentially provided with silver paste, an insulating layer and a dielectric layer from bottom to top, four groups of chemical gold plating are arranged on the dielectric layer, and the bonding pads are arranged on the substrate. A thick copper wire is welded on the bonding pad, and the other end of the thick copper wire is welded on the electroless plating gold. By arranging the dielectric layer, the side wall of the thick copper wire is well protected from being affected by the environment and attacked by other substances, good product performance is ensured, original supplied materials are replaced by electro-coppering and electro-nickeling, needed Au is reduced in a large area, cost is saved, and production efficiency is improved. And as the Cu side wall of the RDL is easily influenced by the environment and other substances, the performance of the product is reduced, and the reliability faces the challenge of failure.

Description

Technical Field

[0001] The utility model relates to the technical field of chip bonding, in particular to a thick copper wire bonding structure. Background Art

[0002] With the vigorous development of chip bonding technology, various types of bonding structures continue to emerge. Among them, the most common is direct bonding on the chip Al pad to complete the connection between the chip and the external circuit. This is more suitable for application scenarios with low overload current requirements. For products with high requirements that require thick copper wires, the bonding structure requires the introduction of RDL lines to achieve (limited by the Al pad spacing and the bonding pressure). The current existing technology is to transfer the pad and then bond the wires through RDL Cu / Ni / Au. However, as the Cu sidewall of RDL is easily affected by the environment (Cu oxidation) and other substances (halogen chlorine attack), the product performance is reduced and the reliability faces the challenge of failure.

[0003] Therefore, when faced with such a situation, it is an important solution to protect the RDL Cu sidewall. Combined with the mature related processes of wafer-level packaging, adding a layer of Polyimider after the RDL can effectively protect the RDL copper sidewall (compared with Molding compound, Polyimider has better dielectric properties). Subsequently, a thick pad is made on the RDL by chemical plating for thick copper wires, which not only meets the wire bonding requirements, but also ensures product performance and improves reliability.

[0004] Therefore, it is necessary to design a thick copper wire bonding structure to solve the above technical problems. Utility Model Content

[0005] The utility model aims to provide a thick copper wire bonding structure to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the utility model provides the following technical solutions: a thick copper wire bonding structure, comprising a substrate, the substrate is at the bottom layer, four groups of pads are arranged on the substrate, the pads are distributed in pairs on both sides of the substrate, the substrate is sequentially provided with silver paste, an insulating layer, and a dielectric layer from bottom to top, four groups of chemical gold plating are arranged on the dielectric layer, a thick copper wire is welded on the pad, and the other end of the thick copper wire is welded on the chemical gold plating.

[0007] According to the above technical solution, four groups of aluminum pads are arranged inside the insulating layer, and the aluminum pads are located at the top of the insulating layer.

[0008] According to the above technical solution, the dielectric layer includes four groups of electroplated copper in the middle, electroplated nickel is arranged above the electroplated copper, and chemically plated nickel is arranged above the electroplated nickel.

[0009] According to the above technical solution, the length and width of the electroplated copper and the electroplated nickel are consistent.

[0010] According to the above technical solution, the chemically plated nickel penetrates the dielectric layer, and the chemically plated gold is located above the dielectric layer.

[0011] According to the above technical solution, the material in the dielectric layer is polyimide.

[0012] Compared with the prior art, the beneficial effects achieved by the utility model are as follows: the utility model provides a dielectric layer to better protect the side wall of the thick copper wire from environmental influences and attacks by other substances, thereby ensuring better product performance, and uses electroplated copper and electroplated nickel to replace the original incoming materials, thereby reducing the required Au large area and saving costs. As the Cu side wall of RDL is easily affected by the environment and other substances, resulting in a decrease in product performance, the reliability faces the technical problem of failure challenges. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0014] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0015] Figure 2 It is a front view schematic diagram of the overall structure of the utility model;

[0016] In the figure: 1. substrate; 2. soldering pad; 3. thick copper wire; 4. silver paste; 5. insulating layer; 6. aluminum pad; 7. electroplated copper; 8. electroplated nickel; 9. dielectric layer; 10. chemical nickel plating; 11. chemical gold plating. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] See also Figure 1-2The utility model provides a technical solution: a thick copper wire bonding structure, comprising a substrate 1, the substrate 1 is at the bottom layer, four groups of pads 2 are arranged on the substrate 1, the pads 2 are distributed on both sides of the substrate 1 in pairs, the substrate 1 is sequentially provided with a silver paste 4, an insulating layer 5, and a dielectric layer 9 from bottom to top, four groups of chemically plated gold 11 are arranged on the dielectric layer 9, a thick copper wire 3 is welded on the pad 2, and the other end of the thick copper wire 3 is welded on the chemically plated gold 11;

[0019] Four groups of aluminum pads 6 are arranged inside the insulating layer 5, and the aluminum pads 6 are located at the top of the insulating layer 5;

[0020] The dielectric layer 9 includes four groups of electroplated copper 7 in the middle, electroplated nickel 8 is arranged above the electroplated copper 7, and chemically plated nickel 10 is arranged above the electroplated nickel 8;

[0021] The length and width of the electroplated copper 7 and the electroplated nickel 8 are consistent;

[0022] The chemically plated nickel 10 penetrates the dielectric layer 9, and the chemically plated gold 11 is located above the dielectric layer 9;

[0023] The material in the dielectric layer 9 is polyimide.

[0024] Installation method: After silver paste 4 is coated on the substrate 1, an insulating layer 5 is covered on the silver paste 4. Electroplated copper 7 and then electroplated nickel 8 are set on the silver paste 4. The polyimide is covered to form a dielectric layer 9. The position where the wire is required is exposed by means of glue coating, exposure and development. Then, chemical plating is used to form chemical nickel plating 10 and chemical gold plating 11. One end of the thick copper wire 3 is connected. A part of the chemical nickel plating 10 is in the dielectric layer 9, and the other part is outside the dielectric layer 9. In this way, the metal copper involved in this structure is better protected.

[0025] The device is provided with a dielectric layer 9 to better protect the side wall of the thick copper wire 3 from environmental influences and attacks by other substances, thereby ensuring better product performance. Electroplated copper 7 and electroplated nickel 8 are used to replace the original incoming materials, so that the required Au area is reduced and costs are saved. As the Cu side wall of RDL is easily affected by the environment and other substances, the product performance is reduced and the reliability faces the technical problem of failure challenge.

[0026] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0027] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A thick copper wire bonding structure, comprising a substrate (1), characterized in that: The substrate (1) is at the bottom layer. Four groups of pads (2) are arranged on the substrate (1). The pads (2) are distributed in pairs on both sides of the substrate (1). The substrate (1) is provided with silver paste (4), an insulating layer (5), and a dielectric layer (9) in sequence from bottom to top. Four groups of chemical gold plating (11) are arranged on the dielectric layer (9). Thick copper wires (3) are welded on the pads (2). The other end of the thick copper wires (3) is welded on the chemical gold plating (11).

2. A thick copper wire bonding structure according to claim 1, characterized in that: Four groups of aluminum pads (6) are arranged inside the insulating layer (5), and the aluminum pads (6) are located at the top of the insulating layer (5).

3. A thick copper wire bonding structure according to claim 2, characterized in that: The dielectric layer (9) includes four groups of electroplated copper (7) in the middle, electroplated nickel (8) is arranged above the electroplated copper (7), and chemically plated nickel (10) is arranged above the electroplated nickel (8).

4. A thick copper wire bonding structure according to claim 3, characterized in that: The length and width of the electroplated copper (7) and the electroplated nickel (8) are consistent.

5. A thick copper wire bonding structure according to claim 4, characterized in that: The chemically plated nickel (10) penetrates the dielectric layer (9), and the chemically plated gold (11) is located above the dielectric layer (9).

6. A thick copper wire bonding structure according to claim 5, characterized in that: The material in the dielectric layer (9) is polyimide.

Images