Packaging method and semiconductor packaging structure capable of improving gold pad recognition

Abstract

The present invention provides a packaging method and a semiconductor packaging structure that can improve the recognition of a gold pad. The packaging method comprises the following steps: 1) providing a substrate, forming a metal seed layer on the surface of the substrate; 2) forming a base copper layer by electroplating at a predetermined position on the surface of the metal seed layer, wherein the base copper layer partially covers the metal seed layer; 3) forming a photoresist layer, wherein the photoresist layer covers the base copper layer and the metal seed layer not covered by the base copper layer, and exposing and developing the photoresist layer to form an opening on the surface of the corresponding base copper layer, wherein the opening exposes a portion of the base copper layer; 4) forming a copper pad layer, which is located on the upper surface of the base copper layer; 5) forming a nickel pad layer and a gold pad layer by electroplating on the surface of the copper pad layer in sequence; 6) performing a photoresist stripping process to remove the photoresist layer remaining on the surface of the structure obtained in step 5); 7) removing the metal seed layer not covered by the base copper layer. The present invention is helpful to improve the recognition of the gold pad and the production yield of the wire bonding process.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor packaging, and in particular relates to a packaging method and a semiconductor packaging structure capable of improving the recognition of a gold pad. Background Art

[0002] Wafer-level packaging (WLP) technology is a process that uses a whole wafer as a packaging and testing object, and cuts the wafer into individual finished chips after packaging, which is very different from the traditional chip packaging process. The chip size packaged by the WLP process can be reduced by more than 20% compared with the chip size packaged by the traditional process, so WLP packaging has become the mainstream of the packaging market. In the WLP packaging process, the formation of conductive pillars is a very important process, and the quality of this process is directly related to the electrical performance of the final product. In the process of preparing conductive pillars by the existing WLP packaging process, photoresist is first applied to the surface of the device formed with base copper and exposed and developed to define the position of the conductive pillar, and then the base copper surface at the position corresponding to the conductive pillar is electroplated to form a nickel pad layer and a gold pad layer to form a conductive pillar, and then a photoresist stripping process is performed to remove the residual photoresist, and then the external conductive structure such as metal leads is electrically connected to the surface of the conductive pillar by a wire bonding process, that is, the surface of the gold pad layer is electrically connected. That is, in the prior art, the base copper first undergoes an exposure and development process, and the nickel pad is directly formed on the base copper surface after exposure and development. After the photoresist is stripped and etched, the roughness of the gold pad and the base copper surface not covered by the gold pad are very similar. In addition, the colors of gold and copper themselves are very close, which makes it difficult for the black and white recognition lens of the wire bonding machine to accurately distinguish the gold pad and the base copper, and thus it is difficult to accurately bond the metal lead to the gold pad surface, resulting in a decrease in the conductive performance of the device or even complete failure of the device. Summary of the invention

[0003] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a packaging method and a semiconductor packaging structure that can improve the recognition of the gold pad, so as to solve the problem that in the existing WLP packaging process, the base copper first undergoes an exposure and development process, and the nickel pad layer is directly formed on the base copper surface after exposure and development, and then after photoresist stripping and etching, the roughness of the gold pad layer and the base copper surface not covered by the gold pad layer are very similar, and the colors of gold and copper themselves are very close, which makes it difficult for the black and white recognition lens of the wire bonding machine to accurately distinguish the gold pad and the base copper, and thus it is difficult to accurately bond the metal lead to the gold pad surface, resulting in a decrease in the conductive performance of the device or even complete failure of the device.

[0004] To achieve the above-mentioned object and other related objects, the present invention provides a packaging method capable of improving the recognition of gold pads, the packaging method comprising the steps of:

[0005] 1) providing a substrate, and forming a metal seed layer on the surface of the substrate;

[0006] 2) forming a base copper layer at a predetermined position on the surface of the metal seed layer by electroplating, wherein the base copper layer partially covers the metal seed layer;

[0007] 3) forming a photoresist layer, wherein the photoresist layer covers the base copper layer and the metal seed layer not covered by the base copper layer, and exposing and developing the photoresist layer to form an opening on a surface corresponding to the base copper layer, wherein the opening exposes a portion of the base copper layer;

[0008] 4) forming a copper pad layer in the opening by electroplating, wherein the copper pad layer is located on the upper surface of the base copper layer;

[0009] 5) forming a nickel pad layer and a gold pad layer on the surface of the copper pad layer by electroplating in sequence, wherein the nickel pad layer is located on the upper surface of the copper pad layer, and the gold pad layer is located on the upper surface of the nickel pad layer;

[0010] 6) performing a photoresist stripping process to remove the photoresist layer remaining on the surface of the structure obtained in step 5);

[0011] 7) Using an etching process to remove the metal seed layer not covered by the base copper layer.

[0012] Optionally, the orthographic projection of the opening is located in the middle of the base copper layer.

[0013] Optionally, the packaging method further comprises the step of performing a wire bonding process after step 7) to electrically connect the gold pad layer and the metal lead.

[0014] Optionally, the etching process in step 7) is wet etching.

[0015] Optionally, the surface area of ​​the gold pad layer is smaller than the surface area of ​​the copper pad layer.

[0016] Optionally, the metal seed layer includes a copper seed layer.

[0017] Optionally, the thickness of the gold pad layer is smaller than the thickness of the nickel pad layer and smaller than the thickness of the copper pad layer.

[0018] The present invention also provides a semiconductor packaging structure, which includes a substrate, a metal seed layer, a base copper layer, a copper pad layer, a nickel pad layer and a gold pad layer from bottom to top, wherein the surface roughness of the copper pad layer is greater than the surface roughness of the base copper layer, and the surface area of ​​the gold pad layer is smaller than the surface area of ​​the base copper layer and not greater than the surface area of ​​the copper pad layer.

[0019] Optionally, the semiconductor packaging structure further includes a metal lead, and the metal lead is electrically connected to the gold pad layer.

[0020] Optionally, the metal seed layer includes a copper seed layer.

[0021] Optionally, the surface area of ​​the gold pad layer is smaller than the surface area of ​​the copper pad layer.

[0022] As described above, the present invention forms a photoresist layer on the surface of the base copper, and after exposure and development, a copper pad layer is electroplated at a position corresponding to the position where the gold pad layer is to be formed, and then a nickel pad layer and a gold pad layer are formed in sequence. Since the copper pad layer is formed by electroplating, the surface roughness is relatively large, which is greatly different from the roughness of the base copper after exposure and development, and thus the copper pad layer is displayed as a darker color in the circumferential direction; and since the copper pad layer is added, the height difference between the gold pad layer and the base copper is further increased, so the black and white lens of the wire bonding machine can easily identify the position of the gold pad layer (the circumferential contour of the copper pad layer outlines the position of the gold pad layer, and the inside of the copper pad layer is the surface where the positive projection of the gold pad layer is located), thereby enabling the metal lead to be accurately bonded to the surface of the gold pad layer, which helps to improve the conductive performance of the device and improve the production yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The flowchart of the packaging method for improving the recognition of gold pads of the present invention is shown.

[0024] Figures 2 to 7 Display as Figure 1 Schematic diagram of the structure presented in each step of the packaging method.

[0025] Figure 8 Display as Figure 7 Local scanning electron microscope image.

[0026] Component number description

[0027] 11 Substrate

[0028] 12 Metal Seed Layer

[0029] 13 Base copper layer

[0030] 14 Photoresist layer

[0031] 15 Copper pad

[0032] 16 Nickel underlayment

[0033] 17 Gold cushion

[0034] 18 Metal lead

[0035] Steps S1 to S7 DETAILED DESCRIPTION

[0036] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0037] See also Figures 1 to 8 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0038] like Figure 1 As shown, the present invention provides a packaging method capable of improving the recognition of gold pads, the packaging method comprising the steps of:

[0039] S1: providing a substrate 11, and forming a metal seed layer 12 on a surface of the substrate 11;

[0040] S2: Forming a base copper layer 13 by electroplating at a predetermined position on the surface of the metal seed layer 12, wherein the base copper layer 13 partially covers the metal seed layer 12, and a structure such as Figure 2 As shown;

[0041] S3: forming a photoresist layer 14, wherein the photoresist layer 14 covers the base copper layer 13 and the metal seed layer 12 not covered by the base copper layer 13, and exposing and developing the photoresist layer 14 to form an opening on the surface corresponding to the base copper layer 13, wherein the opening exposes a portion of the base copper layer 13, and the obtained structure is as follows: Figure 3 As shown;

[0042] S4: forming a copper pad layer 15 in the opening by electroplating, wherein the copper pad layer 15 is located on the upper surface of the base copper layer 13 (the copper pad layer 15 is in contact with the base copper layer 13), and the obtained structure is as follows: Figure 4 As shown;

[0043] S5: Forming a nickel pad layer 16 and a gold pad layer 17 on the surface of the copper pad layer 15 by electroplating in sequence, wherein the nickel pad layer 16 is located on the upper surface of the copper pad layer 15, and the gold pad layer 17 is located on the upper surface of the nickel pad layer 16. The obtained structure is as follows: Figure 5 As shown;

[0044] S6: performing a photoresist stripping process to remove the photoresist layer 14 remaining on the surface of the structure obtained in step 5), i.e., step S5;

[0045] S7: Using an etching process to remove the metal seed layer 12 not covered by the base copper layer 13, the obtained structure is as follows Figure 6 shown.

[0046] The formation process of the conductive column in the prior art is: forming a base copper-photoresist coating-exposure and development-electroplating nickel layer-electroplating gold layer (the gold layer at this stage is actually an independent conductive connection structure, i.e., a gold pad, commonly known as a pad). Since the thickness of the nickel layer and the gold layer are relatively thin, and the color of the gold layer is very close to the color of the base copper, it is difficult to identify the gold layer during the top-down scanning of the black and white lens of the wire bonding machine (i.e., it is difficult to distinguish the gold layer from the base copper), and since the surface area of ​​the gold pad is usually very small, it is difficult to electrically connect the gold layer with other structures, such as it is difficult to accurately bond the metal lead to the surface of the gold pad, resulting in a decrease in the electrical performance of the device. The present invention forms a photoresist layer on the surface of the base copper, defines the position of the conductive column through exposure and development, and then electroplates to form a copper pad layer at the position corresponding to the gold pad to be formed (i.e., the position of the conductive column), and then sequentially forms a nickel pad layer and a gold pad layer. Since the copper pad layer is formed by electroplating, the surface roughness of the electroplated copper formed by electroplating on the surface of the base copper will be further increased, showing a large difference from the surface roughness of the base copper after exposure and development, so the copper pad layer is displayed as a darker color in the circumferential direction; the nickel pad layer and the gold pad layer deposited on the surface of the copper pad layer with greater roughness can also have a larger surface roughness (the nickel pad layer and the gold pad layer are usually relatively thin, such as less than 500nm); and due to the addition of the copper pad layer, the height difference between the gold pad layer and the base copper is further increased, so the black and white lens of the wire bonding machine can easily identify the position of the gold pad (the circumferential contour of the copper pad layer outlines the position of the gold pad layer), thereby accurately bonding the metal lead to the surface of the gold pad layer, which helps to improve the conductivity of the device and improve the production yield.

[0047] In one example, the substrate 11 includes a device layer, a dielectric layer located on the device layer, and a metal wire layer located on and in the dielectric layer and electrically connected to the device in the device layer. More specifically, the device layer can be a semiconductor wafer, in which a plurality of semiconductor chips are formed; the material of the dielectric layer includes but is not limited to one or more combinations of epoxy resin, silica gel, PI, PBO, BCB, silicon oxide, phosphorus silicon glass, and fluorine-containing glass; the method of forming the dielectric layer includes but is not limited to chemical vapor deposition or physical vapor deposition; the method of forming the metal wire layer includes but is not limited to physical vapor deposition or electroplating, such as first forming a pattern corresponding to the metal wire layer in the dielectric layer by photolithography and etching, and then using physical vapor deposition or electroplating to fill metal to form the metal wire layer; the material of the metal wire layer includes but is not limited to one or more combinations of copper, aluminum, nickel, gold, silver, and titanium. After completing the corresponding packaging process, the semiconductor wafer is cut to form independent chips.

[0048] In another example, the substrate 11 includes a carrier layer, an adhesive layer on the carrier layer, and a base layer on the adhesive layer; the carrier layer includes but is not limited to glass and ceramics, and the base layer includes but is not limited to silicon wafers. After completing the corresponding packaging process, for example, the structure obtained after completing the wire bonding process is bonded to other substrates to electrically lead out the chips on other substrates using the structure prepared by the present invention. The specific structure of the substrate is not limited in this embodiment. However, no matter what structure the substrate is, it is crucial to accurately align and connect conductive structures such as metal leads and gold pads to ensure good conductivity between conductive interconnect structures, which has an impact on device performance, and is therefore applicable to the packaging method of the present invention.

[0049] As an example, before the step 2), the predetermined position can be defined by a graphical process, or by forming an alignment mark to define the predetermined position, to ensure that the subsequent base copper layer 13 is formed at the predetermined position. The base copper layer 13 partially covers the metal seed layer 12, so that the metal seed layer 12 not covered by the base copper layer 13 has a certain height difference with the base copper layer 13. The metal seed layer 12 includes but is not limited to a copper seed layer, and the method for forming the metal seed layer 12 includes but is not limited to one or a combination of vapor deposition and electroplating. In order to ensure a close fit between the metal seed layer 12 and the substrate 11, a metal adhesion layer can be formed on the surface of the substrate 11 before forming the metal seed layer 12, and the metal seed layer 12 is formed on the surface of the metal adhesion layer, and the metal adhesion layer includes but is not limited to a titanium layer.

[0050] As an example, the orthographic projection of the opening is located in the middle of the base copper layer 13 , which helps to improve the alignment accuracy of subsequent processes.

[0051] As an example, the thickness of the copper pad layer 15 formed in step 4) is greater than or equal to 100 μm. Although the surface of the base copper layer 13 has a certain degree of roughness after being corroded by the degumming solution during the exposure and development process in step 3), the surface of the copper pad layer 15 formed by electroplating on the rough base copper layer 13 will become rougher, and the introduction of the copper pad layer 15 further increases the height difference between the subsequently formed gold pad layer 17 and the base copper. Under the black and white recognition lens of the wire bonding machine, the rougher the surface, the darker the color. The gold pad layer 17 is formed on the upper surface of the nickel pad layer 16 and the gold pad layer 17. When the lens looks down from the gold pad layer 17 from top to bottom, the gold pad layer 17 falls on the base copper surface and the circumference of the copper pad layer 15 presents a black circle, and the gold pad layer 17 is inside the circle. Therefore, with the help of the copper pad layer 15, the black and white recognition lens of the wire bonding machine can accurately identify the gold pad layer 17, thereby accurately bonding the metal lead 18 to the surface of the gold pad layer 17.

[0052] In the step 5), since they are confined in the opening of the photoresist layer 14, the surface areas of the nickel pad layer 16 and the gold pad layer 17 will not be greater than the surface area of ​​the copper pad layer 15. In order to further improve the recognition and avoid the circumferential edge of the copper pad layer 15 from being covered, the surface areas of the nickel pad layer 16 and the gold pad layer 17 can be smaller than the surface area of ​​the copper pad layer 15, for example, a mask is used to cover the circumferential part of the opening, and the nickel pad layer 16 and the gold pad layer 17 are sequentially formed on the surface of the copper pad layer 15 according to the mask. The surface area of ​​the nickel pad layer 16 and the surface area of ​​the gold pad layer 17 can be the same.

[0053] As an example, the packaging method further includes the step of performing a wire bonding process after step 7) to electrically connect the gold pad 17 and the metal lead 18. Due to the aforementioned process improvement, the black and white lens of the wire bonding machine can accurately identify the gold pad 17 and accurately bond the metal lead 18 to the surface of the gold pad 17. Of course, in other examples, other conductive structures and the gold pad 17 may also be electrically connected, which is not strictly limited in this embodiment. However, no matter what kind of conductive interconnection structure is used, accurately identifying the gold pad 17 is a very important step, and thus can be improved based on the method of the present invention.

[0054] As an example, in order to avoid damaging the gold pad layer 17 during the process of removing the metal seed layer 12 not covered by the base copper layer 13, the etching process of step 7) is preferably a wet etching process, that is, an etching solution with a high etching selectivity ratio for gold and copper is selected for etching. Since the thickness of the base copper layer 13 is itself greater than the thickness of the metal seed layer 12, in the process of etching the metal seed layer 12 not covered by the base copper layer 13, although a part of the surface of the base copper layer 13 will be etched away, the impact is not great (of course, as needed, the base copper layer 13 can be formed as thick as possible when electroplating). In other examples, a protective layer can also be formed on the surface of the base copper layer 13 and the gold pad layer 17 before the etching process to protect the gold pad layer 17 and the base copper layer to be retained, and then the protective layer is removed. After this step, the base copper layer 13 forms independent areas, and the conductive columns composed of the copper pad layer 15, the nickel pad layer 16 and the gold pad layer 17 are formed in these areas.

[0055] As an example, the thickness of the gold pad layer 17 is smaller than the thickness of the nickel pad layer 16 and smaller than the thickness of the copper pad layer 15 (preferably, the thickness of the gold pad layer 17 is smaller than the thickness of the nickel pad layer 16 and smaller than the thickness of the copper pad layer 15) to minimize production costs.

[0056] As an example, after forming the gold pad layer 17, the remaining photoresist layer 14 is removed, and the obtained structure is as follows: Figure 6 Then, a wire bonding process is performed to electrically connect the gold pad 17 and the metal lead 18, and the resulting structure is as shown. Figure 7 Of course, in other examples, the residual photoresist layer 14 may be removed after the wire bonding process is completed. This is not strictly limited in this embodiment, but it is preferred to remove the residual photoresist layer 14 before the wire bonding process to avoid damage to the metal lead 18.

[0057] As an example, after the electroplating process of the gold pad is completed, the obtained structure can be cleaned, such as by using an alkaline solution, and then dried. The drying process includes but is not limited to purging with a clean gas, or drying.

[0058] The inventor has tested this method several times in the factory. Figure 8 As shown, in the semiconductor packaging structure prepared by this method, the outline of the gold pad layer is clearly visible on the base copper (the outline is actually the circumferential edge of the copper pad layer), indicating that the gold pad layer can be significantly identified using this packaging method, which helps to accurately bond the metal lead to the surface of the gold pad layer in the future, thereby significantly improving device performance and production yield. At present, this method has been fully promoted and used in the factory where the inventor works.

[0059] like Figure 7As shown, the present invention also provides a semiconductor packaging structure, which can be prepared based on the packaging method described in any of the above schemes. The semiconductor packaging structure includes a substrate 11, a metal seed layer 12, a base copper layer 13, a copper pad layer 15, a nickel pad layer 16 and a gold pad layer 17 from bottom to top, that is, the metal seed layer 12 is formed on the upper surface of the substrate 11, the base copper layer 13 is formed on the surface of the metal seed layer 12, the copper pad layer 15 is formed on the upper surface of the base copper 13, the nickel pad layer 16 is formed on the upper surface of the copper pad layer 15, and the gold pad layer 17 is formed on the upper surface of the nickel pad layer 16, wherein the surface roughness of the copper pad layer 15 is greater than the surface roughness of the base copper layer 13 and the surface area of ​​the gold pad layer 17 is less than the surface area of ​​the base copper layer 13 and not greater than the surface area of ​​the copper pad layer 15. The metal seed layer 12, the base copper layer 13, the copper pad layer 15, the nickel pad layer 16 and the gold pad layer 17 together constitute a conductive column, and there are usually multiple conductive columns, and the multiple conductive columns are distributed at intervals. The circumferential edge of the copper pad engraves the outline of the gold pad, which helps to accurately identify the gold pad, helps to accurately bond the metal lead to the surface of the gold pad, and helps to improve the quality of the device.

[0060] As an example, the semiconductor package structure further includes a metal lead 18 , and the metal lead 18 is electrically connected to the gold pad 17 .

[0061] As an example, the metal seed layer 12 includes a copper seed layer.

[0062] As an example, the surface area of ​​the gold pad layer 17 is smaller than the surface area of ​​the copper pad layer 15 to ensure that the copper pad layer is not completely covered by the gold pad layer, so that the gold pad layer can be accurately identified through the circumferential edge of the copper pad layer.

[0063] As an example, the thickness of the gold pad layer 17 is less than or equal to the thickness of the nickel pad layer 16, and both are preferably less than the thickness of the copper pad layer, and the thickness of the copper pad layer is preferably greater than or equal to 100 μm, so as to further increase the height difference between the gold pad layer and the base copper, which helps to further increase the recognition of the gold pad layer. For a further introduction to the semiconductor packaging structure, please refer to the above content, which will not be repeated for the purpose of brevity.

[0064] As described above, the present invention provides a packaging method and a semiconductor packaging structure that can improve the recognition of gold pads. The packaging method includes the following steps: 1) providing a substrate, forming a metal seed layer on the surface of the substrate; 2) forming a base copper layer by electroplating at a predetermined position on the surface of the metal seed layer, and the base copper layer partially covers the metal seed layer; 3) forming a photoresist layer, the photoresist layer covers the base copper layer and the metal seed layer not covered by the base copper layer, and exposing and developing the photoresist layer to form an opening on the surface corresponding to the base copper layer, and the opening exposes part of the base copper layer; 4) forming a copper pad layer by electroplating in the opening, and the copper pad layer is located on the upper surface of the base copper layer; 5) forming a nickel pad layer and a gold pad layer by electroplating on the surface of the copper pad layer in sequence, and the nickel pad layer is located on the upper surface of the copper pad layer, and the gold pad layer is located on the upper surface of the nickel pad layer; 6) performing a photoresist stripping process to remove the photoresist layer remaining on the surface of the structure obtained in step 5); 7) using an etching process to remove the metal seed layer not covered by the base copper layer. The present invention helps the black and white lens of the wire bonding machine to accurately identify the position of the gold pad layer, thereby accurately bonding the metal lead to the surface of the gold pad layer, which helps to improve the conductive performance of the device and improve the production yield. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0065] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A packaging method capable of improving the recognition of a gold pad, characterized in that: The packaging method comprises the steps of: 1) providing a substrate, and forming a metal seed layer on the surface of the substrate; 2) forming a base copper layer at a predetermined position on the surface of the metal seed layer by electroplating, wherein the base copper layer partially covers the metal seed layer; 3) forming a photoresist layer, wherein the photoresist layer covers the base copper layer and the metal seed layer not covered by the base copper layer, and exposing and developing the photoresist layer to form an opening on a surface corresponding to the base copper layer, wherein the opening exposes a portion of the base copper layer; 4) forming a copper pad layer in the opening by electroplating, wherein the copper pad layer is located on the upper surface of the base copper layer; 5) forming a nickel pad layer and a gold pad layer on the surface of the copper pad layer by electroplating in sequence, wherein the nickel pad layer is located on the upper surface of the copper pad layer, and the gold pad layer is located on the upper surface of the nickel pad layer; The thickness of the gold pad layer and the nickel pad layer is less than 500 nm, and the thickness of the copper pad layer is greater than or equal to 100 μm; the surface area of ​​the gold pad layer and the surface area of ​​the nickel pad layer are less than the surface area of ​​the base copper layer and not greater than the surface area of ​​the copper pad layer; 6) performing a photoresist stripping process to remove the photoresist layer remaining on the surface of the structure obtained in step 5); 7) The metal seed layer not covered by the base copper layer is removed by an etching process, wherein the metal seed layer, the base copper layer, the copper pad layer, the nickel pad layer and the gold pad layer together constitute a conductive column.

2. The packaging method according to claim 1, characterized in that: The orthographic projection of the opening is located in the middle of the base copper layer.

3. The packaging method according to claim 1, characterized in that: The packaging method further comprises the step of performing a wire bonding process after step 7) to electrically connect the gold pad layer and the metal lead.

4. The packaging method according to claim 1, characterized in that: The etching process in step 7) is wet etching.

5. The packaging method according to claim 1, characterized in that: The metal seed layer includes a copper seed layer.

6. The packaging method according to claim 1, characterized in that: The thickness of the gold pad layer is smaller than the thickness of the nickel pad layer and smaller than the thickness of the copper pad layer.

7. A semiconductor packaging structure, characterized in that: The semiconductor packaging structure includes a substrate, a metal seed layer, a base copper layer, a copper pad layer, a nickel pad layer and a gold pad layer from bottom to top, and the metal seed layer, the base copper layer, the copper pad layer, the nickel pad layer and the gold pad layer together constitute a conductive column; wherein the surface roughness of the copper pad layer is greater than the surface roughness of the base copper layer, the surface area of ​​the gold pad layer is smaller than the surface area of ​​the base copper layer and not greater than the surface area of ​​the copper pad layer, the thickness of the gold pad layer and the nickel pad layer is less than 500nm, and the thickness of the copper pad layer is greater than or equal to 100μm.

8. The semiconductor package structure according to claim 7, wherein: The semiconductor packaging structure further includes a metal lead, and the metal lead is electrically connected to the gold pad layer.

9. The semiconductor package structure according to claim 7, wherein: The metal seed layer includes a copper seed layer.

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