CN114934302A

CN114934302A - Cyanide-free electrogilding liquid and application thereof

Info

Publication number: CN114934302A
Application number: CN202210467430.9A
Authority: CN
Inventors: 任长友; 王彤; 邓川; 张喜; 文剑
Original assignee: Shenzhen United Blue Ocean Gold Material Technology Co ltd; Huawei Technologies Co Ltd
Current assignee: Shenzhen United Blue Ocean Gold Material Technology Co ltd; Huawei Technologies Co Ltd
Priority date: 2022-04-27
Filing date: 2022-04-27
Publication date: 2022-08-23

Abstract

The invention relates to the technical field of cyanide-free gold plating, and discloses a cyanide-free electrogilding solution and application thereof. The gold electroplating solution comprises: a gold source, a conductive salt, a buffering agent, an additive, an auxiliary complexing agent and a cerium salt; wherein the additive is at least one of antimony-containing compound, arsenic-containing compound and thallium-containing compound, and the auxiliary complexing agent is selected from organic phosphonic acid and/or water-soluble amine. The cyanide-free gold electroplating solution provided by the invention can accelerate the oxidation of sulfite through adding cerium salt, regulate and control the concentration of sulfite, weaken the complexing action of sulfite accumulated in the plating solution on monovalent gold ions, thereby improving the long-term stability of the plating solution and providing stable plating layer properties such as hardness and roughness.

Description

Cyanide-free electrogilding solution and application thereof

Technical Field

The invention relates to the technical field of cyanide-free gold plating, in particular to cyanide-free electrogilding liquid and application thereof.

Background

The most commonly used semiconductor metal interconnect materials are aluminum, copper, and gold. Gold has excellent chemical stability, and the aspects of electric conduction and heat conduction are only inferior to those of silver and copper. The gold is not oxidized at normal temperature or under heating condition, does not react with most chemical substances, has good weldability, can be thermally pressed and bonded, and has low contact resistance. Therefore, gold plating is widely used in the fields of electronic circuit boards, electronic connectors, semiconductor manufacturing, and the like.

CN113832508A discloses a cyanide-free gold electroplating solution, its application, a method for electroplating gold bumps, gold bumps and electronic components, the solution comprises: a gold source, a conductive salt, a buffer, an additive and an organic phosphonic acid, the additive being selected from antimony-containing compounds and/or arsenic-containing compounds. The precipitation efficiency of the plating solution is more than 99%, the prepared gold plating layer has low roughness (less than 100nm) and high purity (99.99%), and the obtained gold bump has a regular shape.

However, during the electroplating process, gold ions in the gold plating solution are deposited on the cathode surface, and the gold sulfite Au (SO) is required to be continuously supplemented ₃ ) ₂ ] ^3- So as to maintain the concentration of gold ions in the gold plating solution, the gold sulfite salt releases free sulfite continuously, and the sulfite is accumulated in the plating solution continuously. The more sulfite, the stronger the coordination capability to gold ions, thereby affecting the stability of the plating solution, reducing the service life (MTO) of the plating solution, and possibly causing the problems of gold precipitation, increased roughness of the plating layer, reduced hardness and the like at the later stage of use.

Disclosure of Invention

The invention aims to solve the problems of poor stability of a gold plating solution in long-term use, short service cycle and low quality of a plating layer in the later period in the prior art, and provides a cyanide-free gold plating solution which has long service cycle and can provide stable hardness and roughness of the plating layer for a long time.

In order to achieve the above object, a first aspect of the present invention provides a cyanide-free gold electroplating bath, wherein the gold electroplating bath comprises: a gold source, a conductive salt, a buffering agent, an additive, an auxiliary complexing agent and a cerium salt; wherein the additive is at least one of antimony-containing compound, arsenic-containing compound and thallium-containing compound, and the auxiliary complexing agent is selected from organic phosphonic acid and/or water-soluble amine.

In a second aspect, the invention provides the use of the cyanide-free gold electroplating solution of the first aspect of the invention for gold plating, preferably for semiconductor fabrication.

Through the technical scheme, the beneficial technical effects obtained by the invention are as follows:

1) the cyanide-free electrogilding solution provided by the invention can accelerate the oxidation of sulfite through adding cerium salt, regulate and control the concentration of sulfite, weaken the complexing action of the sulfite accumulated in the electrogilding solution on monovalent gold ions, thereby improving the long-term stability of the electrogilding solution and providing stable plating layer properties such as hardness and roughness.

2) The hardness of the plating layer prepared by the cyanide-free electrogilding plating solution provided by the invention is between 50 and 110HV, the roughness Ra is less than or equal to 20nm (the thickness of the plating layer is 3 mu m), and the cyanide-free electrogilding plating solution is particularly suitable for the field of semiconductor manufacturing.

Drawings

FIG. 1 is a graph showing MTO test results of cyanide-free gold electroplating baths prepared in example 1 and comparative example 1 of the present application.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The first aspect of the present invention provides a cyanide-free gold electroplating bath, wherein the gold electroplating bath comprises: a gold source, a conductive salt, a buffer, an additive, an auxiliary complexing agent and a cerium salt; wherein the additive is at least one of antimony-containing compound, arsenic-containing compound and thallium-containing compound, and the auxiliary complexing agent is selected from organic phosphonic acid and/or water-soluble amine.

When the gold plating solution of CN113832508A is used for a long time, a large amount of sulfite is accumulated in the gold plating solution, resulting in a decrease in the long-term stability of the gold plating solution. The inventor of the invention finds that the cerium salt added into the gold plating solution can play a role in promoting the oxidation of sulfite and reducing the content of sulfite, thereby improving the service cycle of the gold plating solution and maintaining the stability of the hardness and the roughness of the gold plating layer.

In a preferred embodiment, the gold source is selected from the group consisting of gold sulfates and/or sulfites, preferably at least one of gold (I) sodium sulfite, gold (I) potassium sulfite, gold (I) ammonium sulfite. In the present invention, the roman numeral (I) in parentheses represents the corresponding valence of the element unless otherwise specified.

In a preferred embodiment, the gold source is used in an amount such that the concentration of gold ions in the electrogalvanic gold plating bath is from 1 to 20 g/L. In the present invention, the concentration of the gold ion may be 1g/L, 2g/L, 3g/L, 4g/L, 5g/L, 6g/L, 7g/L, 8g/L, 9g/L, 10g/L, 11g/L, 12g/L, 13g/L, 14g/L, 15g/L, 16g/L, 17g/L, 18g/L, 19g/L, 20g/L, or any value in the range of any two of the above values, and more preferably 8 to 15 g/L.

In a preferred embodiment, the conductive salt is selected from at least one of sodium sulfite, potassium sulfite, ammonium sulfite, sodium bisulfite, potassium bisulfite, sodium sulfate, potassium sulfate, ammonium sulfate, sodium bisulfate, and potassium bisulfate, and is preferably sodium sulfite and sodium sulfate.

In a preferred embodiment, the concentration of the conductive salt is 10 to 120 g/L. In the present invention, the concentration of the conductive salt may be any value in the range of 10g/L, 15g/L, 20g/L, 25g/L, 30g/L, 35g/L, 40g/L, 45g/L, 50g/L, 55g/L, 60g/L, 65g/L, 70g/L, 75g/L, 80g/L, 90g/L, 100g/L, 110g/L, 120g/L, and any two of the above values, and more preferably 10 to 80 g/L.

In a preferred embodiment, the conductive salts are sodium sulfite and sodium sulfate; wherein the concentration of sodium sulfite is 30-80g/L, and can be 30g/L, 35g/L, 40g/L, 45g/L, 50g/L, 55g/L, 60g/L, 65g/L, 70g/L, 75g/L, 80g/L, and any value in the range formed by any two numerical values. The concentration of the sodium sulfate is 10-60g/L, and can be 10g/L, 15g/L, 20g/L, 25g/L, 30g/L, 35g/L, 40g/L, 45g/L, 50g/L, 55g/L, 60g/L, and any value in the range formed by any two numerical values.

In a preferred embodiment, the buffer is selected from at least one of edetate, phosphate, tartrate, citrate, preferably from disodium edetate and/or disodium hydrogen phosphate.

In a preferred embodiment, the buffer is present at a concentration of 1 to 30 g/L. In the present invention, the concentration of the buffer may be 1g/L, 2g/L, 3g/L, 4g/L, 5g/L, 6g/L, 7g/L, 8g/L, 9g/L, 10g/L, 11g/L, 12g/L, 13g/L, 14g/L, 15g/L, 16g/L, 17g/L, 18g/L, 19g/L, 20g/L, 25g/L, 30g/L, or any value in the range of any two values thereof, and more preferably 5 to 20 g/L.

In a preferred embodiment, the additive is one of the antimony (IV) -containing compound, the arsenic (III) -containing compound, or the thallium (II) -containing compound; wherein, the antimony-containing compound is selected from at least one of antimony oxide, antimony halide, antimony oxyhalide, antimonide, antimonate and organic antimonide, and is further preferably selected from at least one of sodium antimony tartrate, potassium antimony tartrate, sodium antimonate and potassium antimonate; the arsenic-containing compound is at least one selected from oxides of arsenic, arsenite and arsenic-containing organic matters, and is preferably sodium arsenite and/or arsenic trioxide; the thallium-containing compound is at least one selected from thallium sulfate, thallium nitrate and thallium acetate, and is preferably thallium sulfate.

In a preferred embodiment, the concentration of the additive is 1-100mg/L calculated by antimony, arsenic and thallium elements. Wherein, in the invention, the concentration of the additive in terms of antimony, arsenic and thallium can be 1mg/L, 2mg/L, 3mg/L, 4mg/L, 5mg/L, 6mg/L, 7mg/L, 8mg/L, 9mg/L, 10mg/L, 11mg/L, 12mg/L, 13mg/L, 14mg/L, 15mg/L, 16mg/L, 17mg/L, 18mg/L, 19mg/L, 20mg/L, 21mg/L, 22mg/L, 23mg/L, 24mg/L, 25mg/L, 26mg/L, 27mg/L, 28mg/L, 29mg/L, 30mg/L, 31mg/L, 32mg/L, 33mg/L, 34mg/L, 35mg/L, 36mg/L, 37mg/L, 38mg/L, 39mg/L, 40mg/L, 41mg/L, 42mg/L, 43mg/L, 44mg/L, 45mg/L, 46mg/L, 47mg/L, 48mg/L, 49mg/L, 50mg/L, 60mg/L, 70mg/L, 80mg/L, 90mg/L, 100mg/L, and any value in the range of any two numerical values mentioned above, and further preferably 5 to 50 mg/L.

In the invention, the additive is calculated by antimony, arsenic and thallium, and is calculated by the total amount of antimony, arsenic and thallium contained in the additive.

In a preferred embodiment, the auxiliary complexing agent is selected from an organic phosphonic acid or a water-soluble amine; wherein the organic phosphonic acid is selected from at least one of methylene phosphonic acid, same carbon phosphonic acid and carboxylic phosphonic acid, preferably at least one of hydroxyethylidene diphosphonic acid (HEDP), aminotrimethylene phosphonic Acid (ATMP) and ethylene diamine tetramethylene phosphonic acid (EDTMP); more preferably hydroxyethylidene diphosphonic acid and/or aminotrimethylene phosphonic acid; the water-soluble amine is at least one selected from ethylenediamine, propylenediamine, diethylenetriamine, triethylenetetramine and pentaethylenetetramine.

In a preferred embodiment, the concentration of the auxiliary complexing agent is 1 to 50 g/L. Wherein, in the invention, the concentration of the auxiliary complexing agent can be 1g/L, 2g/L, 3g/L, 4g/L, 5g/L, 6g/L, 7g/L, 8g/L, 9g/L, 10g/L, 11g/L, 12g/L, 13g/L, 14g/L, 15g/L, 16g/L, 17g/L, 18g/L, 19g/L, 20g/L, 21g/L, 22g/L, 23g/L, 24g/L, 25g/L, 26g/L, 27g/L, 28g/L, 29g/L, 30g/L, 35g/L, 40g/L, 45g/L, 50g/L, and any value in the range of any two of the above numerical values, more preferably 4 to 30 g/L.

In a preferred embodiment, the auxiliary complexing agent is an organic phosphonic acid, and the weight ratio of the organic phosphonic acid to the additive (calculated by antimony, arsenic and thallium elements) is 10-2500:1, preferably 100-; for example, 100:1, 200:1, 300:1, 400:1, 500:1, 600:1, 700:1, 800:1, 900:1, 1000:1, and any value within the range of any two of the foregoing values.

In a preferred embodiment, the auxiliary complexing agent is a water-soluble amine, and the concentration of the water-soluble amine is 1-30 g/L. In the present invention, the concentration of the water-soluble amine may be any value in the range of 1g/L, 5g/L, 10g/L, 15g/L, 20g/L, 25g/L, 30g/L, or any two of the above-mentioned values, and is preferably 5 to 20 g/L. When the concentration of the water-soluble amine is more than 30g/L, the complexing ability with gold (I) becomes strong, so that the plating film is excessively densified, and there is a possibility that poor soldering may occur, and when it is less than 1g/L, the plating solution becomes unstable and the plating layer becomes rough.

In a preferred embodiment, the cerium salt is selected from one or more of cerium (II) sulfate, cerium (iii) nitrate, cerium (iii) chloride, cerium (iii) phosphate, cerium (iii) acetate.

In a preferred embodiment, the cerium salt has a concentration of 0.1 to 30mg/L in terms of Ce element. Wherein, in the invention, when the concentration of the cerium salt calculated by Ce element is lower than 0.1mg/L, the cerium salt can not effectively play a role in catalyzing the oxidation of sulfite, thus causing the poor long-term stability of the gold electroplating solution; more than 30mg/L, the gold color or the purity of gold may be decreased by doping, resulting in deterioration of soldering properties. The cerium salt may be present in a concentration of 0.1mg/L, 0.5mg/L, 0.75mg/L, 1mg/L, 1.5mg/L, 2mg/L, 2.5mg/L, 3mg/L, 3.5mg/L, 4mg/L, 4.5mg/L, 5mg/L, 7.5mg/L, 10mg/L, 12.5mg/L, 15mg/L, 17.5mg/L, 20mg/L, 25mg/L, 30mg/L in terms of Ce element, or in any range of any two of these values, and more preferably 0.5 to 5 mg/L.

In a preferred embodiment, the mass ratio between said cerium salt and said buffer is 1-20 mg: 5g, preferably 1-10 mg: 5g of the total weight.

In the gold electroplating solution provided by the invention, the cerium salt and the buffer agent act synergistically to maintain the balance of sulfite radicals in the gold electroplating solution so as to improve the stability of the gold electroplating solution and prevent the problems of gold precipitation, increased roughness of a plating layer, reduced hardness and the like of the gold electroplating solution in the later use stage.

In a preferred embodiment, the electrogilding bath further comprises a pH additive, wherein the pH additive is selected from acids or bases, such as sulfurous acid, sulfuric acid, sodium hydroxide, potassium hydroxide, ammonia.

In a preferred embodiment, the electrogold plating solution has a pH of 7 to 9. In the present invention, the pH of the gold electroplating bath may be 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7, 7.8, 7.9, 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, or any of the two ranges of the above numerical values, and is preferably 7.4 to 9.

In a preferred embodiment, the preparation method of the cyanide-free gold electroplating solution comprises the step of putting the components into water to be completely dissolved. The preparation method is not particularly limited, and the preparation method can be carried out according to conventional operations in the field.

In a second aspect, the invention provides the use of the cyanide-free gold electroplating solution of the invention in gold plating, preferably in semiconductor manufacturing.

In a preferred embodiment, the plating conditions of the cyanide-free gold plating solution are not particularly limited, and the plating can be performed according to the conventional conditions in the art. Further preferably, the electroplating temperature is 40-70 ℃, preferably 50-60 ℃; the current density of the electroplating is 0.1-2A/dm ² (ASD), preferably 0.2-1.2 ASD.

In a preferred embodiment, the purity of the gold in the electrogilding is more than or equal to 99.95 percent, preferably more than or equal to 99.99 percent by electroplating with the cyanide-free electrogilding liquid.

The present invention will be described in detail below by way of examples.

Oxidation experiment 1 of sodium sulfite

In a 1L beaker, the components shown in Table 1 were added to prepare a series of solutions to be tested 1-8. After standing at room temperature for 2 days, 4 days and 6 days, the sodium sulfite content in the solution was measured by sampling, and the time required for the oxidation reaction of sodium sulfite to proceed to 1/2 (i.e., when the sodium sulfite content in the solution decreased by half) was calculated by straight line fitting, and the test results are shown in table 1.

Wherein sodium sulfite is measured by back titration method, and excessive I is added ₂ Reacts with sodium sulfite in the solution, and then the unreacted I is titrated with 0.05M sodium thiosulfate solution ₂ Thereby reversing the sodium sulfite content of the solution.

TABLE 1

As can be seen from the test results of the solution 1 to be tested, the oxidation reaction of sulfite radical in the pure sodium sulfite aqueous solution proceeds very quickly, t _1/2 It was 4.6 days. As is clear from the test results of the solution 2 to be tested, after 5g of disodium ethylenediaminetetraacetate was added to the aqueous sodium sulfite solution, the oxidation reaction of sodium sulfite was largely inhibited, t _1/2 Increasing to 51.3 days.

According to the test results of the solutions 3-6 to be tested, 10ppm of Fe is added in the form of sulfate in the presence of disodium ethylene diamine tetraacetate ²⁺ ，Fe ³⁺ ，Co ²⁺ The oxidation rate of sodium sulfite is not effectively improved, but Ce is added ³⁺ But can effectively improve the oxidation rate, t, of sodium sulfite _1/2 The reduction was 7.0 days.

Considering that co-deposition of transition metals may affect the purity of gold, further affecting the appearance of the plating solution and its soldering properties, Ce in the plating solution ³⁺ Should be as low as possible, as can be seen from the test results of the liquid 7 to be tested, when Ce is present ³⁺ When the concentration of (2) is reduced to 1ppm, t _1/2 9.8 days, indicating a low concentration of Ce ³⁺ Still can play the role of catalyzing the oxidation of sodium sulfite.

In the actual electroplating process, nitrogen protection is required to reduce the oxidation of sodium sulfite. By comparing the test results of the solutions 7 and 8 to be tested, t is known _1/2 The increase from 9.8 days to 17.7 days showed that 1ppm Ce was added when nitrogen blanket was used ³⁺ The oxidation of sodium sulfite can be slowed down. Presence of Ce in solution ³⁺ Under the condition, the purpose of regulating and controlling the concentration of sulfite in the plating solution can be achieved by regulating the content of oxygen.

Example 1

Adding 40g of sodium sulfite, 20g of sodium sulfate, 10g of ethylenediamine and 5g of disodium ethylenediamine tetraacetate into a 2L beaker, adding 600mL of deionized water, stirring to completely dissolve, adding 15g of gold sodium sulfite with the gold element content, 10mg of sodium arsenite with the arsenic content and 1mg of cerous sulfate with the cerium content, continuously adding deionized water to adjust the volume of the plating solution to 1L, and adjusting the pH value to 8 to obtain the cyanide-free gold electroplating solution.

Comparative example 1

The same as in example 1 except that cerous sulfate was omitted, a cyanide-free gold electroplating solution containing no cerous sulfate was obtained.

Test example 1

The cyanide-free gold electroplating baths prepared in example 1 and comparative example 1 were subjected to an MTO test (MTO — Over), wherein one round of MTO test was completed every 15g/L of gold element consumed during the test. The MTO test method is as follows:

placing cyanide-free electrogilding solution in a 2L Shanben plating tank for electroplating in air atmosphere, wherein the temperature of the plating solution is 55 ℃, and the current density is 0.8 ASD; during the test, the gold concentration in the plating solution is maintained between 14 and 16g/L and the pH is maintained between 7.8 and 8.2 by adding the sodium gold sulfite, and the concentration of the sulfite radical in the plating solution is monitored in real time.

In the MTO test process, when one round of MTO test is completed, taking the corresponding plating solution to perform the stability test of the plating solution: in order to avoid the influence of copper or zinc dissolution on gold electroplating solution, 100nm of electroplated gold is pre-plated on a brass Herl cell test piece, the temperature of the electroplating solution is 55 ℃, the current intensity is 0.3A, the electroplating time is 5min, and the electroplating solution is considered to be unstable when gold particles are separated out from the electroplating solution in the electroplating process.

In the MTO test process, one piece to be plated is replaced every time one round of MTO test is completed. Wherein the part to be plated is a PVD gold-plated silicon wafer (Si/SiO) ₂ a/Ti/Au structure). And (2) testing the roughness and the hardness of the plated piece obtained in each round of MTO test in the MTO test process, wherein the thickness of a plating layer in the plated piece is 3 mu m, and the hardness of the plating layer is tested as follows: the plated article was annealed at 270 ℃ for 30min, and then the hardness of the plated article was measured using a vickers hardness tester and a nanoindenter (Nano-Indenter G200). And (3) testing the roughness of the plating layer: the roughness of the coating was measured using a kirnshi VK-X3100.

The test results in test example 1 are shown in fig. 1. As can be seen from FIG. 1, in the MTO test of the cyanide-free gold electroplating solution of example 1, the concentration of sodium sulfite was maintained at 62 to 67g/L, and the plated article obtained in each cycle had a hardness of 55 to 58HV after annealing, a roughness Ra of 11 to 15nm, and stable hardness and roughness properties. The Hull cell experiment shows that the plating solution is not decomposed in the MTO test process, no gold is separated out, and the stability of the cyanide-free gold electroplating solution is good.

The cyanide-free electrogilding solution of comparative example 1 had a sodium sulfite concentration of 61g/L at 0MTO initially and gradually increased as the MTO test proceeded to 105g/L at 3MTO throughout the MTO test; the hardness of the plating layer of the plated part obtained in each period in the MTO test process is gradually reduced from 60HV, 54HV and 48HV to 41HV, the roughness Ra is gradually increased from 12nm, 19nm and 26nm to 35nm, and the fluctuation of the hardness and the roughness is large; the Hull cell experiment showed that the bath separated gold slightly at 2MTO and began to separate gold severely at 3MTO, and the cyanide-free gold electroplating bath of comparative example 1 was good in stability at the initial time, but began to become poor in stability after 2 MTO.

As can be seen from the results of the MTO test of comparative example 1 and test example 1, a small amount of Ce was contained in the plating solution ³⁺ The oxidation of sodium sulfite can be accelerated, and the stable sodium sulfite concentration in the plating bath is stable to the stability of the plating bath, the hardness and the roughness of the plating layerHave a very important impact. The cyanide-free electrogilding solution provided by the invention can obviously improve the service cycle of the electrogilding solution and maintain the stability of the hardness and the roughness of the electrogilding layer for a long time.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A cyanide-free electrogilding bath, comprising: a gold source, a conductive salt, a buffering agent, an additive, an auxiliary complexing agent and a cerium salt; wherein the additive is at least one of antimony-containing compound, arsenic-containing compound and thallium-containing compound, and the auxiliary complexing agent is selected from organic phosphonic acid and/or water-soluble amine.

2. The electrogalvanic gold plating bath according to claim 1, wherein the gold source is selected from the group consisting of gold sulfate and/or sulfite, preferably at least one of gold (I) sodium sulfite, gold (I) potassium sulfite, gold (I) ammonium sulfite;

preferably, the gold source is used in an amount such that the concentration of gold ions in the electrogilding bath is 1-20g/L, more preferably 8-15 g/L.

3. The gold electroplating bath according to claim 1, wherein the conductive salt is at least one selected from the group consisting of sodium sulfite, potassium sulfite, ammonium sulfite, sodium bisulfite, potassium bisulfite, sodium sulfate, potassium sulfate, ammonium sulfate, sodium bisulfate, and potassium bisulfate, preferably sodium sulfite and sodium sulfate;

preferably, the concentration of the conductive salt is 10-120g/L, and more preferably 10-80 g/L;

preferably, the conductive salt is sodium sulfite and sodium sulfate; wherein the concentration of the sodium sulfite is 30-80g/L, and the concentration of the sodium sulfate is 10-60 g/L.

4. The gold electroplating bath according to claim 1, wherein the buffer is selected from at least one of ethylenediaminetetraacetic acid, phosphate, tartrate, citrate, preferably from disodium ethylenediaminetetraacetate and/or disodium hydrogenphosphate;

preferably, the concentration of the buffer is 1 to 30g/L, more preferably 5 to 20 g/L.

5. The gold electroplating bath according to claim 1, wherein the additive is selected from one of the antimony-containing compound, arsenic-containing compound, thallium-containing compound;

preferably, the antimony-containing compound is selected from at least one of antimony oxide, antimony halide, antimony oxyhalide, antimony oxide, antimony salt and organic antimony compound, and is further preferably selected from at least one of sodium antimony tartrate, potassium antimony tartrate, sodium antimonate and potassium antimonate;

preferably, the arsenic-containing compound is at least one selected from arsenic oxide, arsenite and arsenic-containing organic matter, and is further preferably sodium arsenite and/or arsenic trioxide;

preferably, the thallium-containing compound is selected from at least one of thallium sulfate, thallium nitrate, thallium acetate, and further preferably thallium sulfate;

preferably, the concentration of the additive is 1-100mg/L, and more preferably 5-50mg/L calculated by antimony, arsenic and thallium.

6. The gold electroplating bath according to claim 1, wherein the auxiliary complexing agent is selected from an organic phosphonic acid or a water soluble amine;

preferably, the organic phosphonic acid is selected from at least one of methylene phosphonic acid, same carbon phosphonic acid and carboxylic phosphonic acid, and further preferably selected from at least one of hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid and ethylenediamine tetramethylene phosphonic acid; more preferably hydroxyethylidene diphosphonic acid and/or aminotrimethylene phosphonic acid;

preferably, the water-soluble amine is at least one selected from ethylenediamine, propylenediamine, diethylenetriamine, triethylenetetramine and pentaethylenetetramine;

preferably, the concentration of the auxiliary complexing agent is 1-50g/L, and more preferably 4-30 g/L.

7. The gold electroplating bath according to claim 6, wherein the auxiliary complexing agent is an organophosphonic acid, and the weight ratio of the organophosphonic acid to the additive (calculated as antimony, arsenic, thallium elements) is 10-2500:1, preferably 100-.

8. The gold electroplating bath according to claim 6, wherein the auxiliary complexing agent is a water-soluble amine, and the concentration of the water-soluble amine is 1-30g/L, preferably 5-20 g/L.

9. The gold electroplating bath according to claim 1, wherein the cerium salt is selected from one or more of cerium sulfite, cerium nitrate, cerium chloride, cerium phosphate, and cerium acetate;

preferably, the concentration of the regulator calculated by Ce element is 0.1-30mg/L, and further preferably 0.5-5 mg/L.

10. Use of a cyanide-free gold electroplating bath according to any of claims 1 to 9 for gold plating, preferably for semiconductor manufacture.