Gold-silver alloy structure for semiconductor device and preparation method therefor

Abstract

The present invention belongs to the technical field of semiconductor device preparation. Disclosed are a gold-silver alloy structure for a semiconductor device and a preparation method therefor. The main body of the gold-silver alloy structure is a gold-silver alloy bump, and a porous gold layer is provided on the surface of the gold-silver alloy bump. After the gold-silver alloy bump is prepared by electroplating, reverse electroplating is performed by using the same electroplating solution, or by using an etching solution (the main difference between the etching solution and the electroplating solution lies in the absence of gold salt and silver salt), silver on the surface of the gold-silver alloy bump is etched, and a porous gold layer is formed on the surface of the gold-silver alloy bump, thereby solving the technical problem that the silver in the gold-silver alloy bump is easily oxidized or sulfidized, and achieving use of a gold-silver alloy instead of pure gold for a semiconductor device. The present invention does not require adding new electroplating equipment or chemical plating equipment, and the process is simple and easy to implement.

Description

Gold-silver alloy structure for semiconductor device and method for manufacturing the same TECHNICAL FIELD

[0001] The present invention belongs to the field of semiconductor device manufacturing, and particularly relates to a gold-silver alloy structure for semiconductor device and a method for manufacturing the same. BACKGROUND

[0002] Due to the continuous rise in gold prices, the manufacturing cost of semiconductor devices that use a large amount of gold, such as liquid crystal driving chips, memory chips, or compound semiconductor chips, is under great pressure. The use of gold-silver alloy instead of pure gold for bumping of packaged chips can greatly save costs, but when the gold content in the gold-silver bump is low, the surface of the gold-silver alloy is not resistant to oxidation or sulfidation, and in the subsequent flip-chip process, the gold-silver bump needs to be bonded to the copper circuit of the flexible printed circuit board (FPC) through tin or gold microparticles in anisotropic conductive adhesive (ACF). Due to the oxidation or sulfidation of silver, the bonding is poor. Therefore, the use of gold-silver alloy instead of pure gold urgently needs to solve the problem of insufficient oxidation or sulfidation resistance of silver in the gold-silver alloy. In particular, the top surface of the bump, that is, the bonding interface, needs to be particularly avoided from oxidation or sulfidation of silver.

[0003] In order to solve the problem of rising costs of semiconductor devices due to the continuous rise in gold prices, the prior art has adopted various technical solutions to replace pure gold with gold-silver alloy to reduce costs. TWI469288B mentions electroplating gold-silver bumps, and in order to prevent silver oxidation, one of gold, palladium, copper, or nickel is electroplated or chemically plated on the top or side surface of the gold-silver bump to prevent silver oxidation, but copper or nickel is more prone to oxidation than silver. TW201044527A mentions electroplating gold-silver bumps containing not less than 80% silver content, and then forming a protective layer on the surface of the gold-silver alloy by replacing gold or reducing gold to prevent silver oxidation. TW201019440A mentions that the material of the silver bump can be selected from pure silver or silver alloy, and the silver alloy of the silver bump can contain not less than 80% silver content, and then a layer of pure gold or gold alloy is plated on the surface of the silver alloy to solve the problem of oxidation resistance. The above operations, due to the use of different components for the protective layer than the electroplating of the gold-silver alloy, require an additional plating tank containing different chemicals to prepare the protective layer, which undoubtedly increases the complexity of the process and the investment cost of the production line.

[0004] CN117542818B through a large number of research, found that by making the gold content in the gold-silver bump to more than 60%, the anti-oxidation or anti-sulfuration performance of silver in the gold-silver bump can be obviously improved. Specifically, in the same electroplating tank, using the same gold-silver alloy plating solution, a gold-silver alloy body with a gold content of 20% to 50% is prepared as a connecting layer by low current density electroplating, and the height of the plating layer is 7 to 20 μm, and then a protective layer with a gold content of more than 60% is prepared by electroplating under high current density, and the height of the protective layer is 10 to 500 nm. Since the same plating solution can be used in the same plating tank to realize the preparation of the above gold-silver bump structure only by the current density, the implementation of the process is greatly simplified and the equipment investment is reduced.

[0005] US5773897A invented a flip chip structure, including a monolithic microwave integrated circuit formed on a module substrate and mounted on a component substrate, the module substrate further comprising a plurality of solder bumps for securing the module substrate to the component substrate, the solder bumps comprising electroplated silver posts having a first diameter and covered with electroplated solder (tin-lead solder) having a second diameter, wherein the second diameter is greater than the first diameter (about 25-50 μm), wherein solder is also used to prevent oxidation of silver. However, if the diameter of the solder is large, short circuiting between adjacent bumps during thermal compression is prone to occur.

[0006] Through the above analysis of the prior art, it can be seen that in order to solve the technical problem that silver in the gold-silver alloy is easy to oxidize or sulfurate, the prior art adopts three solutions: first, a layer of gold or alloy is electroplated on the surface of the gold-silver as a protective layer, in addition to the gold-silver alloy electroplating tank, a new pure gold electroplating tank or chemical plating is needed, which increases the complexity of the process and equipment investment. Second, CN117542818B uses the same electroplating solution to prepare gold-silver bumps with different gold contents by controlling the current density, and the top surface of the bump contains gold-silver alloy with gold content of more than 60%, but silver may also oxidize after long-term storage. Third, solder is used to protect the top surface of the gold-silver bump, but solder is prone to flow at high temperatures and is not suitable for preparing fine lines. At present, the pitch between some advanced liquid crystal drive chip bumps has been reduced to below 10 mm, and the solder protection technology solution is not applicable. Secondly, considering that silver and tin form alloys or intermetallic compounds, sheet-shaped substances may be formed, causing short circuiting between bumps. TECHNICAL PROBLEM

[0007] There is an urgent need for a gold-silver alloy structure for a semiconductor and a preparation method thereof, which solves the technical problem that silver in the gold-silver alloy bump is easy to oxidize or sulfurate, and realizes the use of gold-silver alloy instead of pure gold for semiconductor devices, while the process is simple and easy to implement. TECHNICAL SOLUTION

[0008] The purpose of the present application is to provide a gold-silver alloy structure for semiconductor devices and a preparation method thereof. The inventors have invented a simple and practical process method according to the material properties of gold-silver alloy. After the gold-silver alloy bump is prepared by electroplating, the silver on the surface of the gold-silver alloy bump is etched by reverse electroplating using the same electroplating solution or using an etching solution (the main difference between the etching solution and the electroplating solution is that the etching solution does not contain gold salt and silver salt), and a porous gold layer is formed on the surface of the gold-silver alloy bump, thereby solving the technical problem that silver in the gold-silver alloy bump is easily oxidized or sulfided, and achieving the replacement of pure gold with gold-silver alloy for semiconductor devices.

[0009] The primary aspect of the present application is to provide a gold-silver alloy structure for semiconductor devices, wherein the main body of the gold-silver alloy structure is a gold-silver alloy bump, and a porous gold layer is formed on the surface of the gold-silver alloy bump. By forming a porous gold layer on the surface of the gold-silver alloy bump, the porous gold layer forms a laminated structure (the porous gold layer is located on the top surface of the gold-silver alloy bump) or a surrounding structure (the porous gold layer is located on the top surface and the side surface of the gold-silver alloy bump) with the gold-silver alloy bump. The porous gold layer does not contain silver, which avoids the problem of easy oxidation or sulfidation of silver. Since only a porous gold layer is formed on the surface, the bump body is still a gold-silver alloy material, which on the one hand realizes the replacement of pure gold with gold-silver alloy, and on the other hand does not change the hardness of the bump as a whole (the hardness is comparable to that of a pure gold bump). During the bonding process, the porous gold on the top surface of the bump will deform to cover the underlying material, so even if the silver in the main body of the gold-silver alloy bump below the porous gold layer is oxidized or sulfided, it will not affect the bonding quality of the porous gold and the gold microparticles in tin or ACF.

[0010] Further, the gold-silver alloy bump is obtained by electroplating, and the porous gold layer is obtained by reverse electroplating after etching and removing silver from the surface of the gold-silver alloy bump. The reverse electroplating of the present application refers to electroplating in the opposite direction of the current used to prepare the gold-silver alloy bump. The reverse electroplating method provided by the present application is simple and easy to implement, which is embodied in that the electroplating equipment does not need to be replaced, only the direction of the electroplating current needs to be changed; the same electroplating solution can be used for reverse electroplating, or an etching solution can be used for reverse electroplating. The main difference between the etching solution and the electroplating solution is that the etching solution does not contain gold salt and silver salt, and the preparation process of the etching solution is similar to that of the electroplating solution.

[0011] It should be pointed out that although there are many methods for etching and removing silver, in addition to the reverse electroplating provided by the present application, there is also a chemical etching method, for example, Lothar et al. (Proceedings-Electronic Components and Technology Conference, 2022, 873-882) once reported using nitric acid to etch silver in gold-silver alloy to form a porous gold structure. However, the chemical etching method has the following defects and is not suitable for gold-silver alloy bumps of semiconductors, because the semiconductor device contains many materials, such as TiW adhesion layer, aluminum electrode, silicon substrate, silicon dioxide or silicon nitride passivation layer, and nitric acid can easily corrode these materials. The present application uses reverse electroplating etching to form a very thin porous gold layer on the top surface of the gold-silver bump, which not only meets the hardness requirement of the gold-silver bump packaging, but also ensures the reliability of subsequent bonding through the porous gold layer; at the same time, the reverse electroplating method is the same as the method for preparing the main body of the gold-silver alloy bump, except that the current direction is opposite, which will not cause damage to other materials on the semiconductor device.

[0012] Further, the height of the gold-silver alloy bump is 7-20 μm, and the thickness of the porous gold layer is 0.02-2.0 μm. It should be pointed out that the thickness of the above-mentioned porous gold layer is the thickness of the porous gold layer on the top surface or side surface of the final semiconductor device product. Since during the preparation of the semiconductor device product, the seed layer is etched, especially when the seed layer is also gold, the seed layer is also etched, so when the porous gold is obtained by reverse electroplating, the thickness of the porous gold should be appropriately thick, leaving the etching loss amount when the seed layer is etched.

[0013] Another aspect of the present application is to provide a preparation method of a gold-silver alloy structure for a semiconductor device, the semiconductor device comprising a substrate, an electrode, a seed layer, an adhesion layer and a photoresist, the preparation method comprising the following steps:

[0014] S1 preparing a gold-silver electroplating solution, electroplating the semiconductor device in the electroplating solution to obtain a gold-silver alloy bump;

[0015] S2 using the same electroplating equipment, using the gold-silver electroplating solution of step S1 or using an etching solution, changing the current direction to reverse electroplate the semiconductor device, removing the silver component in the top surface of the bump, thereby forming a porous gold layer on the top surface of the bump;

[0016] S3 removing the photoresist using a photoresist remover;

[0017] S4 removing the seed layer;

[0018] S5 removing the adhesion layer;

[0019] S6 annealing the gold-silver alloy bump.

[0020] This preparation method finally obtains the gold-silver alloy bump with the surrounding structure. First, the gold-silver alloy bump is electroplated, the photoresist is removed, then the silver on the top surface of the bump is removed by reverse electroplating to form a porous gold layer, the side wall is not changed because the photoresist protects the side wall, then the photoresist, the seed layer and the adhesion layer are removed, thereby forming the gold-silver alloy bump with the surrounding structure of the gold-silver alloy main body and the porous gold top surface. By adjusting the annealing time and the annealing temperature, the hardness of the gold-silver alloy bump can meet the packaging requirements.

[0021] Further, the electroplating temperature of step S1 is 20-60℃, the current density is 0.3-1.0 A / dm 2 , and the electroplating time is 10-60 min; the electroplating temperature of step S2 is 20-60℃, the current density is 0.01-10 A / dm 2 , and the electroplating time is 0.5-5 min.

[0022] Another aspect of the present application is to provide another preparation method of a gold-silver alloy structure for a semiconductor device, the semiconductor device comprising a substrate, a seed layer, an adhesion layer and a photoresist, the preparation method comprising the following steps:

[0023] S1 preparing a gold-silver electroplating solution, and electroplating the semiconductor device in the electroplating solution to obtain a gold-silver alloy bump;

[0024] S2 removing the photoresist by using a photoresist remover;

[0025] S3 using the same electroplating equipment, using the gold-silver electroplating solution of step S1 or using an etching solution, and performing reverse electroplating on the semiconductor device by changing the current direction, thereby removing the silver component in the alloy on the top surface and the side surface of the bump to form a porous gold layer on the top surface and the side surface of the bump;

[0026] S4 removing the seed layer;

[0027] S5 removing the adhesion layer;

[0028] S6 annealing the gold-silver alloy bump.

[0029] This preparation method finally obtains the gold-silver alloy bump with the surrounding structure. First, the gold-silver alloy bump is electroplated, the photoresist is removed, then the silver on the top surface of the bump is removed by reverse electroplating to form a porous gold layer, the side wall is not changed because the photoresist protects the side wall, then the photoresist, the seed layer and the adhesion layer are removed, thereby forming the gold-silver alloy bump with the surrounding structure of the gold-silver alloy main body and the porous gold top surface. By adjusting the annealing time and the annealing temperature, the hardness of the gold-silver alloy bump can meet the packaging requirements.

[0030] Further, the electroplating temperature of step S1 is 20-60℃, the current density is 0.3-1.0 A / dm 2, the plating time is 10-60 min; the plating temperature of step S3 is 20-60°C, and the current density is 0.01-10 A / dm 2 , the plating time is 0.5-5 min.

[0031] Further, the components of the gold-silver plating solution in the above two preparation methods include potassium cyanide gold (molecular formula KAu(CN)2) 8-15 g / L, potassium cyanide silver (molecular formula KAg(CN)2) 2-6 g / L, hydantoin or its derivative 1-100 g / L, buffer 10-100 g / L, the pH of the gold-silver plating solution is 8-11, the hydantoin derivative includes 5,5-dimethylhydantoin, 5-methylhydantoin, 3,5,5-trimethylhydantoin, 3-methyl-5-ethylhydantoin, 3-methyl-5,5-diethylhydantoin, 3,5,5-triethylhydantoin, 3,5-diethylhydantoin, 5-propylhydantoin, 5-isopropylhydantoin, 1-(hydroxymethyl)-5,5-dimethylhydantoin, and the buffer is selected from one or more of boric acid, sodium tetraborate, phosphate, pyrophosphate, hydroxyethylidene diphosphonic acid, aminotri(methylene)phosphonic acid, tartrate, citrate, ethylenediaminetetraacetate, N-hydroxyethyl ethylenediaminetriacetate, nitrilotriacetate, or iminodiacetate.

[0032] Further, the components of the etching solution in the above two preparation methods include hydantoin or its derivative 1-100 g / L, buffer 10-100 g / L, the pH of the etching solution is 8-11, the hydantoin derivative includes 5,5-dimethylhydantoin, 5-methylhydantoin, 3,5,5-trimethylhydantoin, 3-methyl-5-ethylhydantoin, 3-methyl-5,5-diethylhydantoin, 3,5,5-triethylhydantoin, 3,5-diethylhydantoin, 5-propylhydantoin, 5-isopropylhydantoin, 1-(hydroxymethyl)-5,5-dimethylhydantoin, and the buffer is selected from one or more of boric acid, sodium tetraborate, phosphate, pyrophosphate, hydroxyethylidene diphosphonic acid, aminotri(methylene)phosphonic acid, tartrate, citrate, ethylenediaminetetraacetate, N-hydroxyethyl ethylenediaminetriacetate, nitrilotriacetate, or iminodiacetate.

[0033] The content of hydantoin and its derivatives is 1-100 g / L, if lower than 1 g / L, the electroplating solution or etching solution needs to be replaced frequently, if higher than 100 g / L, the solution viscosity is too large to affect the uniformity of electroplating or etching. The content of buffer is 10-100 g / L, the buffer not only keeps the pH value stable, but also plays the role of conductive salt. The pH of the electroplating solution or etching solution is 8-11, which is considered that the pKa of 5,5-dimethylhydantoin is 8.1, therefore, above pH 8, 5,5-dimethylhydantoin can form ionic state complex silver ions, and too high pH may cause swelling or penetration of the photoresist.

[0034] Another aspect of the present application is to provide a gold-silver alloy structure obtained according to the above preparation method. Advantages

[0035] The present application has the following beneficial technical effects: the present application solves the problem that the surface of the gold-silver alloy bump is easy to be oxidized or sulfided, thereby ensuring the electrical interconnection reliability of the flip chip; the method provided by the present application does not need to increase new electroplating equipment or chemical plating equipment, and the process is simple and easy to implement. BRIEF DESCRIPTION OF DRAWINGS

[0036] Fig. 1 is a preparation method flow of a laminated structure gold-silver alloy bump.

[0037] Fig. 2 is a preparation method flow of a surrounding structure gold-silver alloy bump.

[0038] Fig. 3a and Fig. 3b are SEM photos of the top surface of the gold-silver alloy bump obtained in Example 1, and Fig. 3c is a SEM photo of the cross section of the gold-silver alloy bump obtained in Example 1.

[0039] Fig. 4a and Fig. 4b are SEM photos of the top surface of the gold-silver alloy bump obtained in Example 2, and Fig. 4c is a SEM photo of the cross section of the gold-silver alloy bump obtained in Example 2.

[0040] Fig. 5 is an electrochemical curve diagram of the etching solution of Example 2 etching the gold electrode or the silver electrode respectively.

[0041] Reference signs: 101 - substrate, 102 - electrode, 103 - passivation layer, 104 - adhesion layer, 105 - seed layer, 106 - photoresist, 107 - gold-silver alloy bump, 108 - porous gold layer. Embodiment of the present application

[0042] The technical solutions of the present application will be described clearly and completely in combination with the drawings in the specification. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application. Embodiment 1

[0043] The embodiment provides a gold-silver alloy bump of a laminated structure and a preparation method. The preparation method flow is shown in Fig. 1, and the specific steps are as follows.

[0044] S1, a gold-silver plating solution is prepared, and a semiconductor device is placed in the plating solution for electroplating. The semiconductor device comprises a substrate 101, an electrode 102, a passivation layer 103, an adhesion layer 104, a seed layer 105 and a photoresist 106, and a gold-silver alloy bump 107 is obtained. The plating solution comprises 12 g / L potassium gold cyanide, 4 g / L potassium silver cyanide, 60 g / L potassium pyrophosphate, 20 g / L hydantoin, and the pH is 9. The plating temperature is 45 DEG C, the current density is 0.8 ASD, and the plating time is 20 min. The height of the gold-silver alloy bump 107 is 10 μm, the gold content is 40 wt%, and the roughness Ra is 71 nm.

[0045] S2, using the same plating equipment and the gold-silver plating solution of step S1, a porous gold layer 108 is formed on the top surface of the gold-silver alloy bump 107 by changing the current direction. The plating temperature is 30 DEG C, the current density is 0.2 ASD, and the plating time is 1 min.

[0046] S3, NMP is used as a photoresist removing solution to remove the photoresist 106.

[0047] S4, 30% H2O2 is used to remove the copper seed layer 105.

[0048] S5, 30% H2O2 is used to remove the TiW adhesion layer 104.

[0049] S6, the gold-silver alloy bump 107 is annealed.

[0050] The morphology of the porous gold layer is observed by a scanning electron microscope. Figs. 3a and 3b are SEM photos of the top surface of the gold-silver bump at 1,000 times and 10,000 times of magnification respectively, and Fig. 3c is a section photo of the gold-silver bump. It can be obviously seen that a nano-porous structure (porous gold layer) is formed on the surface of the bump, which is due to the removal of the surface silver. The thickness of the porous gold layer is about 1.45 μm. Embodiment 2

[0051] The embodiment provides a gold-silver alloy bump of a surrounding structure and a preparation method.

[0052] S1, preparing a gold-silver plating solution, plating a semiconductor device in the plating solution, the semiconductor device comprising a substrate 101, an electrode 102, a passivation layer 103, an adhesion layer 104, a seed layer 105 and a photoresist 106, and obtaining a gold-silver alloy bump 107. The plating solution comprises 12 g / L potassium gold cyanide, 4 g / L potassium silver cyanide, 60 g / L potassium pyrophosphate and 40 g / L 5,5-dimethylhydantoin, and has a pH of 9. The plating temperature is 45 DEG C, the current density is 0.4 ASD, and the plating time is 45 min. The height of the silver alloy bump 107 is 10 μm, the gold content is 25 wt%, and the roughness Ra is 61 nm.

[0053] S2, removing the photoresist 106 by using NMP as a removing solution.

[0054] S3, performing reverse plating on the semiconductor device by using an etching solution to remove silver components in the top surface and side surface of the gold-silver alloy bump 107, so as to form a porous gold layer 108 on the top surface and side surface of the gold-silver alloy bump 107. The etching solution comprises 60 g / L 5,5-dimethylhydantoin and 30 g / L potassium pyrophosphate, and has a pH of 10. The plating temperature is 30 DEG C, the current density is 0.2 ASD, and the plating time is 4 min.

[0055] S4, removing the gold seed layer 105 by using an etching solution of a thiourea system.

[0056] S5, removing the TiW adhesion layer 104 by using H2O2 with a mass concentration of 30%.

[0057] S6, annealing the gold-silver alloy bump 107.

[0058] The porous gold layer is observed by using a scanning electron microscope. FIGS. 4a and 4b are SEM photos of the top surface of the gold-silver bump with a magnification of 1,000 times and 10,000 times, respectively, and FIG. 4c is a section photo of the gold-silver bump. It can be obviously seen that a nano-porous structure (the porous gold layer) is formed on the surface of the bump, which is caused by the removal of silver. The thickness of the porous gold layer is about 1.62 μm. Compared with Example 1, the nano-porous structure formed in Example 2 is more obvious, because the gold content of the gold-silver alloy in Example 1 is 40 wt%, while the gold content in Example 2 is only 25 wt%. In addition, it should be noted that the porous structure of the side wall in Example 2 is not obvious, which is probably caused by the fact that the surface is closer to the cathode than the side wall, so that the electric field of the surface is stronger than that of the side wall.

[0059] Figure 5 compares the etching effect of the etching solution on the gold electrode and the silver electrode, it can be seen that the gold electrode is basically free of dissolution, the silver electrode starts to dissolve from 0.15 V, and the current density increases with the increase of the voltage. This means that the silver on the surface of the gold-silver alloy can be selectively etched by controlling the current density or the voltage, so as to form the structure of the porous gold. Industrial applicability

[0060] The gold-silver alloy bump surface oxidation or sulfidation problem is solved, thereby ensuring the electrical interconnection reliability of the flip chip; the method provided by the application does not need to increase new electroplating equipment or chemical plating equipment, and the process is simple and easy to implement.

Claims

1. A gold-silver alloy structure for a semiconductor device, wherein a main body of the gold-silver alloy structure is a gold-silver alloy bump, and a porous gold layer is on a surface of the gold-silver alloy bump.

2. The gold-silver alloy structure according to claim 1, characterized by The porous gold layer is on a top surface of the gold-silver alloy bump, or the porous gold layer is on a top surface and a side surface of the gold-silver alloy bump.

3. The gold-silver alloy structure of claim 1, wherein The gold-silver alloy bump is obtained by electroplating, and the porous gold layer is obtained by reverse electroplating after etching and removing silver on a surface of the gold-silver alloy bump.

4. The gold-silver alloy structure of claim 1, wherein The height of the gold-silver alloy bump is 7-20 μm, and the thickness of the porous gold layer is 0.02-2.0 μm.

5. A method for producing a gold-silver alloy structure for a semiconductor device, the semiconductor device including a substrate, an electrode, a seed layer, an adhesion layer, and a photoresist, characterized by, The preparation method comprises the following steps: S1.Preparing a gold-silver electroplating solution, and electroplating a semiconductor device in the electroplating solution to obtain a gold-silver alloy bump; S2.Using the same electroplating equipment, using the gold-silver electroplating solution of step S1 or using an etching solution, and performing reverse electroplating on the semiconductor device by changing the direction of current to remove silver components in the alloy on a top surface of the bump, so as to form a porous gold layer on the top surface of the bump; S3.Removing photoresist using a stripping solution; S4.Removing a seed layer; S5.Removing an adhesion layer; S6.Performing annealing treatment on the gold-silver alloy bump.

6. The production method according to claim 5, characterized by The plating temperature of step S1 is 20-60°C, the current density is 0.3-1.0 A / dm 2 , and the plating time is 10-60 min; the plating temperature of step S2 is 20-60°C, the current density is 0.01-10 A / dm 2 , and the plating time is 0.5-5 min.

7. A method for fabricating a gold-silver alloy structure for a semiconductor device, the semiconductor device including a substrate, a seed layer, an adhesion layer, and a photoresist, the method comprising: The preparation method comprises the following steps: S1.Preparing a gold-silver electroplating solution, and electroplating a semiconductor device in the electroplating solution to obtain a gold-silver alloy bump; S2.Removing photoresist using a stripping solution; S3.Using the same electroplating equipment, using the gold-silver electroplating solution of step S1 or using an etching solution, and performing reverse electroplating on the semiconductor device by changing the direction of current to remove silver components in the alloy on a top surface and a side surface of the bump, so as to form a porous gold layer on the top surface and the side surface of the bump; S4.Removing a seed layer; S5.Removing an adhesion layer; S6.Performing annealing treatment on the gold-silver alloy bump.

8. The production method according to claim 7, characterized by, The plating temperature of step S1 is 20-60°C, the current density is 0.3-1.0 A / dm 2 , and the plating time is 10-60 min; the plating temperature of step S3 is 20-60°C, the current density is 0.01-10 A / dm 2 , and the plating time is 0.5-5 min.

9. The production method according to claim 5 or 7, characterized by, The components of the gold-silver electroplating solution comprise potassium gold cyanide 8-15 g / L, potassium silver cyanide 2-6 g / L, hydantoin or its derivative 1-100 g / L, and buffer 10-100 g / L, the pH of the gold-silver electroplating solution is 8-11, the hydantoin derivative comprises 5,5-dimethylhydantoin, 5-methylhydantoin, 3,5,5-trimethylhydantoin, 3-methyl-5-ethylhydantoin, 3-methyl-5,5-diethylhydantoin, 3,5,5-triethylhydantoin, 3,5-diethylhydantoin, 5-propylhydantoin, 5-isopropylhydantoin, 1-(hydroxymethyl)-5,5-dimethylhydantoin, and the buffer is selected from one or more of boric acid, sodium tetraborate, phosphate, pyrophosphate, hydroxyethane diphosphonic acid, aminotri(methylene)phosphonic acid, tartrate, citrate, ethylenediaminetetraacetate, N-hydroxyethyl-ethylenediaminetriacetate, nitrilotriacetate, or iminodiacetate.

10. The production method according to claim 5 or 7, characterized by, The components of the etching solution include 1-100 g / L of hydantoin or its derivatives, 10-100 g / L of buffer, the pH of the etching solution is 8-11, the hydantoin derivatives include 5,5-dimethylhydantoin, 5-methylhydantoin, 3,5,5-trimethylhydantoin, 3-methyl-5-ethylhydantoin, 3-methyl-5,5-diethylhydantoin, 3,5,5-triethylhydantoin, 3,5-diethylhydantoin, 5-propylhydantoin, 5-isopropylhydantoin, 1-(hydroxymethyl)-5,5-dimethylhydantoin, and the buffer is selected from one or more of boric acid, sodium tetraborate, phosphate, pyrophosphate, hydroxyethane diphosphonic acid, aminotrimethylenephosphonic acid, tartrate, citrate, ethylenediaminetetraacetate, N-hydroxyethylethylenediaminetriacetate, nitrilotriacetate or iminodiacetate.

11. A gold-silver alloy structure obtained by the production method according to any one of claims 5 to 10.

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