CN118374846B - Cyanide-free gold electroplating solution suitable for nickel-gold structure process - Google Patents
Cyanide-free gold electroplating solution suitable for nickel-gold structure process Download PDFInfo
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- CN118374846B CN118374846B CN202410807541.9A CN202410807541A CN118374846B CN 118374846 B CN118374846 B CN 118374846B CN 202410807541 A CN202410807541 A CN 202410807541A CN 118374846 B CN118374846 B CN 118374846B
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- 229910052737 gold Inorganic materials 0.000 title claims abstract description 60
- 239000010931 gold Substances 0.000 title claims abstract description 60
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 title claims abstract description 40
- MSNOMDLPLDYDME-UHFFFAOYSA-N gold nickel Chemical group [Ni].[Au] MSNOMDLPLDYDME-UHFFFAOYSA-N 0.000 title claims abstract description 18
- 238000009713 electroplating Methods 0.000 title claims description 22
- 238000000034 method Methods 0.000 title claims description 13
- 230000008569 process Effects 0.000 title claims description 11
- 238000007747 plating Methods 0.000 claims abstract description 71
- 230000007797 corrosion Effects 0.000 claims abstract description 17
- 238000005260 corrosion Methods 0.000 claims abstract description 17
- 239000003112 inhibitor Substances 0.000 claims abstract description 16
- 239000004094 surface-active agent Substances 0.000 claims abstract description 9
- 239000008139 complexing agent Substances 0.000 claims abstract description 8
- 229910017053 inorganic salt Inorganic materials 0.000 claims abstract description 7
- 239000003381 stabilizer Substances 0.000 claims abstract description 7
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical group [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 claims description 24
- -1 gold ion Chemical class 0.000 claims description 21
- PLLBRTOLHQQAQQ-UHFFFAOYSA-N 8-methylnonan-1-ol Chemical compound CC(C)CCCCCCCO PLLBRTOLHQQAQQ-UHFFFAOYSA-N 0.000 claims description 12
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical compound C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 claims description 12
- 239000004440 Isodecyl alcohol Substances 0.000 claims description 12
- 229920000642 polymer Polymers 0.000 claims description 12
- DVECLMOWYVDJRM-UHFFFAOYSA-N pyridine-3-sulfonic acid Chemical compound OS(=O)(=O)C1=CC=CN=C1 DVECLMOWYVDJRM-UHFFFAOYSA-N 0.000 claims description 12
- 235000010265 sodium sulphite Nutrition 0.000 claims description 12
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical group [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 claims description 11
- 229910052938 sodium sulfate Inorganic materials 0.000 claims description 11
- 235000011152 sodium sulphate Nutrition 0.000 claims description 11
- WTEVQBCEXWBHNA-UHFFFAOYSA-N Citral Natural products CC(C)=CCCC(C)=CC=O WTEVQBCEXWBHNA-UHFFFAOYSA-N 0.000 claims description 10
- WTEVQBCEXWBHNA-JXMROGBWSA-N geranial Chemical group CC(C)=CCC\C(C)=C\C=O WTEVQBCEXWBHNA-JXMROGBWSA-N 0.000 claims description 10
- JIVZKJJQOZQXQB-UHFFFAOYSA-N tolazoline Chemical group C=1C=CC=CC=1CC1=NCCN1 JIVZKJJQOZQXQB-UHFFFAOYSA-N 0.000 claims description 10
- NRXPRQASYNPWOV-UHFFFAOYSA-N 2-(4-carboxyquinolin-2-yl)quinoline-4-carboxylic acid;sodium Chemical group [Na].[Na].C1=CC=CC2=NC(C=3C=C(C4=CC=CC=C4N=3)C(=O)O)=CC(C(O)=O)=C21 NRXPRQASYNPWOV-UHFFFAOYSA-N 0.000 claims description 6
- 239000002736 nonionic surfactant Substances 0.000 claims description 5
- ZWZLRIBPAZENFK-UHFFFAOYSA-J sodium;gold(3+);disulfite Chemical compound [Na+].[Au+3].[O-]S([O-])=O.[O-]S([O-])=O ZWZLRIBPAZENFK-UHFFFAOYSA-J 0.000 claims description 3
- 125000003831 tetrazolyl group Chemical group 0.000 claims 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 abstract description 20
- 229910052759 nickel Inorganic materials 0.000 abstract description 10
- 239000004065 semiconductor Substances 0.000 abstract description 4
- 229920002120 photoresistant polymer Polymers 0.000 abstract description 3
- 238000005516 engineering process Methods 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 45
- 230000000052 comparative effect Effects 0.000 description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 13
- 239000011248 coating agent Substances 0.000 description 11
- 238000000576 coating method Methods 0.000 description 11
- 150000003536 tetrazoles Chemical group 0.000 description 10
- 239000008367 deionised water Substances 0.000 description 8
- 229910021641 deionized water Inorganic materials 0.000 description 8
- 238000002474 experimental method Methods 0.000 description 8
- 230000005484 gravity Effects 0.000 description 8
- QXNVGIXVLWOKEQ-UHFFFAOYSA-N Disodium Chemical compound [Na][Na] QXNVGIXVLWOKEQ-UHFFFAOYSA-N 0.000 description 6
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 238000006073 displacement reaction Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 3
- SRCZENKQCOSNAI-UHFFFAOYSA-H gold(3+);trisulfite Chemical compound [Au+3].[Au+3].[O-]S([O-])=O.[O-]S([O-])=O.[O-]S([O-])=O SRCZENKQCOSNAI-UHFFFAOYSA-H 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 125000003396 thiol group Chemical group [H]S* 0.000 description 3
- 231100000331 toxic Toxicity 0.000 description 3
- 230000002588 toxic effect Effects 0.000 description 3
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 description 2
- ABLZXFCXXLZCGV-UHFFFAOYSA-N Phosphorous acid Chemical compound OP(O)=O ABLZXFCXXLZCGV-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 229910052785 arsenic Inorganic materials 0.000 description 2
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 230000007062 hydrolysis Effects 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- MTNDZQHUAFNZQY-UHFFFAOYSA-N imidazoline Chemical compound C1CN=CN1 MTNDZQHUAFNZQY-UHFFFAOYSA-N 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- PXQLVRUNWNTZOS-UHFFFAOYSA-N sulfanyl Chemical class [SH] PXQLVRUNWNTZOS-UHFFFAOYSA-N 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 229910052716 thallium Inorganic materials 0.000 description 2
- BKVIYDNLLOSFOA-UHFFFAOYSA-N thallium Chemical compound [Tl] BKVIYDNLLOSFOA-UHFFFAOYSA-N 0.000 description 2
- NJRXVEJTAYWCQJ-UHFFFAOYSA-N thiomalic acid Chemical compound OC(=O)CC(S)C(O)=O NJRXVEJTAYWCQJ-UHFFFAOYSA-N 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 208000012868 Overgrowth Diseases 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000002390 adhesive tape Substances 0.000 description 1
- 150000007824 aliphatic compounds Chemical class 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000007849 functional defect Effects 0.000 description 1
- IZLAVFWQHMDDGK-UHFFFAOYSA-N gold(1+);cyanide Chemical compound [Au+].N#[C-] IZLAVFWQHMDDGK-UHFFFAOYSA-N 0.000 description 1
- 150000002460 imidazoles Chemical class 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- UUWCBFKLGFQDME-UHFFFAOYSA-N platinum titanium Chemical compound [Ti].[Pt] UUWCBFKLGFQDME-UHFFFAOYSA-N 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000004439 roughness measurement Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 125000000542 sulfonic acid group Chemical group 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/48—Electroplating: Baths therefor from solutions of gold
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D7/00—Electroplating characterised by the article coated
- C25D7/12—Semiconductors
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electroplating And Plating Baths Therefor (AREA)
Abstract
The invention relates to an electroless gold plating solution suitable for nickel-gold structure technology, which comprises the following components in percentage by weight: 3-14g/L of gold ion, 30-100g/L of complexing agent, 10-20g/L of inorganic salt, 10-30mg/L of surfactant, 10-40mg/L of grain refiner, 20-60mg/L of stabilizer, 30-60mg/L of accelerator, 0.5-1.5g/L of corrosion inhibitor, pH value of 7.5-9, temperature of 40-70 ℃ and current density of 0.1-1.0A/dm < 2 >. The cyanide-free gold plating solution is suitable for a semiconductor RDL, UBM, bumping, a gold plating layer obtained on a nickel plating layer has good plating binding force, the obtained gold plating layer with the thickness of 0.05-2.0 mu m is fine in appearance, the roughness is lower than 20nm, the plating solution stability is good, and no obvious attack is caused on photoresist.
Description
Technical Field
The invention relates to the technical field of cyanide-free gold electroplating, in particular to a cyanide-free gold electroplating solution suitable for a nickel-gold structure process.
Background
The electroplating nickel-gold on the circuit board, ceramic substrate, tube shell, chip and other copper wires in the electronic product is a classical plating structure, can meet the functions of welding, wire bonding and the like, has extremely high reliability, and the gold plating of the traditional nickel-gold process adopts cyanide plating solution, and gold ions are derived from potassium aurous cyanide. Cyanide is extremely toxic, and brings great threat to the safety of operators and the environmental safety, so cyanide-free gold plating solution is increasingly valued in the industry.
Cyanide-free gold plating adopts gold sulfite as a gold ion source, is safe and environment-friendly, and is highly favored in the industry. However, conventional cyanide-free gold plating in the industry currently has a general functional problem for nickel-gold structures, namely, poor binding force between a gold layer and a nickel layer. This is because the gold ions or metal grain refiners in the conventional cyanide-free gold plating solution undergo a displacement reaction with the nickel layer, and after the displacement reaction, the displaced gold layer is loosened to cause abnormal binding force.
Patent CN 114892225B discloses a cyanide-free gold plating solution with a nickel-gold structure, wherein the plating solution contains organic phosphonic acid, and when the nickel plating layer is electroplated with gold, the organic phosphonic acid can be selectively adsorbed on the surface of nickel to form a barrier layer, so that the substitution of nickel and gold is effectively inhibited, and the gold plating layer with uniform appearance and good binding force is prepared by using the cyanide-free gold plating. However, the organic phosphoric acid is strong in acidity, and can cause hydrolysis of sulfite radical when being added into the plating solution, so that the cyanide-free gold plating solution is rapidly disabled. The judgment standard of the binding force is as follows: the falling area of less than 10% is evaluated as good binding force, and the falling area of more than 10% is evaluated as poor binding force. This standard is too low to meet the performance requirements of the industry.
Patent CN 107709628B discloses a displacement preventing agent for use in electrolytic hard gold plating solutions, which is characterized by containing at least 1 compound selected from the group consisting of imidazole compounds having mercapto groups, triazole compounds having mercapto groups and aliphatic compounds having sulfonic acid groups and mercapto groups to effectively inhibit nickel-gold displacement, but the mercapto compounds of the present invention have strong adsorptivity on nickel surfaces, and are liable to form an organic insulating film to cause gold leakage or to be intercalated with an organic film between nickel and gold, so that there is a risk of lowering the reliability of the product.
Disclosure of Invention
Aiming at the defects in the technology, the invention provides the cyanide-free gold electroplating solution suitable for the nickel-gold structure process. The cyanide-free gold plating solution is suitable for a semiconductor RDL, UBM, bumping, a gold plating layer obtained on a nickel plating layer has good plating binding force, the obtained gold plating layer with the thickness of 0.05-2.0 mu m is fine in appearance, the roughness is lower than 20nm, the plating solution stability is good, and no obvious attack is caused on photoresist.
In order to achieve the above purpose, the invention provides a cyanide-free gold electroplating solution suitable for nickel-gold structure processes such as semiconductors RDL, UBM, bumping, and the solution formula comprises the following components: 3-14g/L of gold ion, 30-100g/L of complexing agent, 10-20g/L of inorganic salt, 10-30mg/L of surfactant, 10-40mg/L of grain refiner, 20-60mg/L of stabilizer, 30-60mg/L of accelerator and 0.5-1.5g/L of corrosion inhibitor; the surfactant is a nonionic surfactant of isodecyl alcohol and ethylene oxide polymer; the grain refiner is 2,2 '-biquinoline-4, 4' -dicarboxylic acid disodium and 3-pyridine sulfonic acid, and the mass concentration ratio of the two is 1:1 when in use; the corrosion inhibitor is 2-benzyl imidazoline. The surfactant can disperse the current density, plays a role in uniformly starting the plating, and improves the brightness of the plating; the grain refiner can inhibit overgrowth of crystal nucleus to form compact gold-plated film; the corrosion inhibitor can reduce the attack of gold ions on photoresist and prevent the corrosion of the base material.
Wherein the gold ions are provided by sodium gold sulfite; the inorganic salt is sodium sulfate.
Wherein the accelerator is 3, 7-dimethyl-2, 6-octadienal, and can promote the deposition of gold ions, promote the continuous nucleation of gold and improve the uniformity and the binding force.
Wherein the complexing agent is sodium sulfite.
Wherein the pH value is between 7.5 and 9.
Wherein the temperature is between 40 and 70 ℃; the current density is between 0.1 and 1.0A/dm 2. Wherein the stabilizer is tetrazole violet.
The beneficial effects of the invention are as follows: compared with the prior art, the cyanide-free gold electroplating solution suitable for the nickel-gold structure process has the following advantages:
1) The plating layer obtained by the invention has good binding force on a nickel-gold structure, does not contain traditional toxic grain refiners such as thallium, arsenic and the like, adopts 2,2 '-biquinoline-4, 4' -dicarboxylic acid disodium and 3-pyridine sulfonic acid as the grain refiners, and has smooth and fine plating layer.
2) Cyanide-free gold plating of a gold sulfite system is prolonged along with the use time, sulfite can be oxidized into sulfate, when the concentration of the sulfate is accumulated to a certain degree, the specific gravity of the bath solution is higher and higher, and the problem of crystallization can occur after the concentration of the sulfate is accumulated to a certain degree. Therefore, cyanide-free gold plating can strictly control the specific gravity of the bath solution. The invention adopts low-concentration corrosion inhibitor, does not increase the specific gravity of the plating solution, and can greatly prolong the service life of the plating solution.
3) The invention adopts imidazoline corrosion inhibitor to prevent the risk of plating omission caused by excessive adsorption of mercapto corrosion inhibitor adopted in other patents.
4) The invention adopts the nonionic surfactant of isodecyl alcohol and ethylene oxide polymer, can effectively reduce the surface tension of the solution, ensures that the plating solution has stronger in-hole wetting capability and plating hole capability, and ensures that the plating solution is kept clear under the condition of high specific gravity.
Drawings
FIG. 1 is a graph showing the experimental results of example 1 of the present invention;
FIG. 2 is a graph showing the experimental results of example 2 of the present invention;
FIG. 3 is a graph showing the experimental results of example 3 of the present invention;
FIG. 4 is a graph showing the experimental results of example 4 of the present invention;
FIG. 5 is a graph showing the experimental results of comparative example 1 of the present invention;
FIG. 6 is a graph showing the experimental results of comparative example 2 of the present invention;
FIG. 7 is a graph showing the experimental results of comparative example 3 of the present invention;
FIG. 8 is a graph showing the results of comparative example 4 of the present invention.
Detailed Description
In order to more clearly describe the present invention, the present invention will be further described with reference to the text and drawings, wherein the plating solution generally employs pure water as a solvent, and the materials mentioned below as solutes. In addition, the ranges disclosed in this patent, or combinations of ranges of different components, different parameters, should be considered as specifically disclosed herein.
The invention provides a cyanide-free gold electroplating solution suitable for nickel-gold structure processes such as semiconductors RDL, UBM, bumping, and the solution formula comprises the following components: 3-14g/L of gold ion, 30-100g/L of complexing agent, 10-20g/L of inorganic salt, 10-30mg/L of surfactant, 10-40mg/L of grain refiner, 20-60mg/L of stabilizer, 30-60mg/L of accelerator and 0.5-1.5g/L of corrosion inhibitor; the surfactant is a nonionic surfactant of isodecyl alcohol and ethylene oxide polymer; the grain refiner is 2,2 '-biquinoline-4, 4' -dicarboxylic acid disodium and 3-pyridine sulfonic acid, and the mass concentration ratio of the two is 1:1 when in use; the corrosion inhibitor is 2-benzyl imidazoline.
In this embodiment, the gold ions are provided by sodium gold sulfite; the inorganic salt is sodium sulfate.
In this example, the promoter is 3, 7-dimethyl-2, 6-octadienal.
In the embodiment, the complexing agent is sodium sulfite and thiomalic acid, and the mass concentration ratio of the sodium sulfite to the thiomalic acid is 4:1 when the complexing agent is used.
In this example, the pH is between 7.5 and 9.
In this embodiment, the temperature is between 40-70 ℃; the current density is between 0.1 and 1.0A/dm 2.
In this embodiment, the stabilizer is tetrazole violet.
The beneficial effects of the invention are as follows: compared with the prior art, the cyanide-free gold electroplating solution suitable for the nickel-gold structure process has the following advantages:
1) The plating layer obtained by the invention has good binding force on a nickel-gold structure, does not contain traditional toxic grain refiners such as thallium, arsenic and the like, adopts 2,2 '-biquinoline-4, 4' -dicarboxylic acid disodium and 3-pyridine sulfonic acid as the grain refiners, and has smooth and fine plating layer.
2) Cyanide-free gold plating of a gold sulfite system is prolonged along with the use time, sulfite can be oxidized into sulfate, when the concentration of the sulfate is accumulated to a certain degree, the specific gravity of the bath solution is higher and higher, and the problem of crystallization can occur after the concentration of the sulfate is accumulated to a certain degree. Therefore, cyanide-free gold plating can strictly control the specific gravity of the bath solution. The invention adopts low-concentration corrosion inhibitor, does not increase the specific gravity of the plating solution, and can greatly prolong the service life of the plating solution.
3) The invention adopts imidazoline corrosion inhibitor to prevent the risk of plating omission caused by excessive adsorption of mercapto corrosion inhibitor adopted in other patents.
4) The invention adopts the nonionic surfactant of isodecyl alcohol and ethylene oxide polymer, can effectively reduce the surface tension of the solution, ensures that the plating solution has stronger in-hole wetting capability and plating hole capability, and ensures that the plating solution is kept clear under the condition of high specific gravity.
The present invention will be described in detail below by way of examples and comparative examples.
The preparation method of the solution comprises the following steps: taking 1L of plating solution as an example, adding about 600ml of pure water into a beaker, then adding required materials, neutralizing the pH value with alkaline solution, and then adding to avoid hydrolysis of sulfite with acid. After each material is completely dissolved, the next material is added, after the material is completely added and dissolved, the pH value is regulated to a required range by using sodium hydroxide solution or potassium hydroxide solution, sulfuric acid or phosphoric acid solution, and then the water level is supplemented to 1L by using pure water for standby.
The test method of electroplating comprises the following steps: the pH value of the plating solution is regulated to a required range, the temperature of the plating solution is heated to the required range, a platinum titanium net is placed in the plating solution to serve as an anode, a positive electrode of a power supply is communicated, a test piece with a nickel layer serves as a cathode, the negative electrode of the power supply is connected, the plating solution is stirred to enable the plating solution to move, the test piece is soaked in the plating solution for 1min and then is electrified, current is calculated according to the required current density, and electroplating is carried out. And after the electroplating is finished, washing with water and drying.
The binding force test method comprises the following steps: and testing the plating layer by using a hundred-grid method, then using a 3M adhesive tape to adhere the plating layer, tearing and pulling quickly, checking the falling-off condition of the plating layer, judging that the plating layers in all grids are not fallen off, judging that the bonding force is OK, and judging that any grid falls off, judging that the bonding force is NG.
Appearance: macroscopic visual inspection shows that the coating has uniform golden color, no chromatic aberration is observed in the coating by a microscope, and the golden color in the hole is OK. And (3) observing the color difference of the coating by macroscopic vision or an optical microscope, wherein the coating is reddening and blackening, and the blackening of the gold layer in the hole is NG.
The roughness measurement method comprises the following steps: and measuring the roughness of the coating by adopting a step meter, and taking Ra as feedback roughness, wherein the roughness Ra is less than 20nm and is qualified.
Example 1
Gold ion 6g/L, sodium sulfite 30g/L, sodium sulfate 15g/L, isodecyl alcohol and ethylene oxide polymer 10mg/L, 2 '-biquinoline-4, 4' -dicarboxylic acid disodium 5mg/L, 3-pyridine sulfonic acid 5mg/L, 2-benzyl imidazoline 0.5mg/L, tetrazole violet 20mg/L, 3, 7-dimethyl-2, 6-octadienal 30mg/L, the balance deionized water, pH=7.5; the temperature is 30 ℃; the current density is 0.2A/dm 2; electroplating time is 8min.
The appearance diagram of the experiment in example 1 is shown in fig. 1, and the obtained experimental results are that the indexes such as coating binding force, appearance, roughness and the like are all qualified.
Example 2
Gold ion 10g/L, sodium sulfite 100g/L, sodium sulfate 15g/L, isodecyl alcohol and ethylene oxide polymer 10mg/L, 2 '-biquinoline-4, 4' -dicarboxylic acid disodium 15mg/L, 3-pyridine sulfonic acid 15mg/L, 2-benzyl imidazoline 0.5mg/L, tetrazole violet 20mg/L, 3, 7-dimethyl-2, 6-octadienal 40mg/L, the balance deionized water, pH=8; the current density is 0.2A/dm 2; the temperature is 50 ℃ and the electroplating time is 4min.
The appearance diagram of the experiment in example 2 is shown in fig. 2, and the obtained experimental results are that the indexes such as coating binding force, appearance, roughness and the like are all qualified.
Example 3
Gold ion 10g/L, sodium sulfite 50g/L, sodium sulfate 10g/L, isodecyl alcohol and ethylene oxide polymer 30mg/L, 2 '-biquinoline-4, 4' -dicarboxylic acid disodium 20mg/L, 3-pyridine sulfonic acid 20mg/L, 2-benzyl imidazoline 1mg/L, tetrazole violet 40mg/L, 3, 7-dimethyl-2, 6-octadienal 50mg/L, the balance deionized water, and pH=8.5; the current density is 0.8A/dm 2; the temperature is 55 ℃; electroplating time is 2min.
The appearance diagram of the experiment in example 3 is shown in fig. 3, and the obtained experimental results are that the indexes such as coating binding force, appearance, roughness and the like are all qualified.
Example 4
14G/L of gold ion, 70g/L of sodium sulfite, 10g/L of sodium sulfate, 30mg/L of isodecyl alcohol and ethylene oxide polymer, 10mg/L of 2,2 '-biquinoline-4, 4' -dicarboxylic acid disodium, 10mg/L of 3-pyridine sulfonic acid, 1mg/L of 2-benzyl imidazoline, 60mg/L of tetrazole violet, 60mg/L of 3, 7-dimethyl-2, 6-octadienal, and the balance of deionized water, wherein pH=9; the temperature is 50 ℃; the current density is 1A/dm 2; the electroplating time is 1min.
The appearance diagram of the experiment in example 4 is shown in fig. 4, and the obtained experimental results are that the indexes such as coating binding force, appearance, roughness and the like are all qualified.
Comparative example 1
Gold ion 10g/L, sodium sulfite 100g/L, sodium sulfate 15g/L, 2 '-biquinoline-4, 4' -dicarboxylic acid disodium 15mg/L, 3-pyridine sulfonic acid 15mg/L, 2-benzyl imidazoline 0.5mg/L, tetrazole violet 20mg/L, 3, 7-dimethyl-2, 6-octadienal 40mg/L, and deionized water in balance, pH=8; the current density is 0.2A/dm 2; the temperature is 50 ℃ and the electroplating time is 4min.
The appearance diagram of the experiment of comparative example 1 is shown in fig. 5, the comparative example 1 lacks the surfactant compared with the example 2, and the obtained experimental result is that the appearance and the roughness of the coating are disqualified and the binding force is qualified;
comparative example 2
10G/L of gold ion, 100g/L of sodium sulfite, 15g/L of sodium sulfate, 10mg/L of isodecyl alcohol and ethylene oxide polymer, 0.5mg/L of 2-benzyl imidazoline, 20mg/L of tetrazole violet, 40mg/L of 3, 7-dimethyl-2, 6-octadienal and the balance of deionized water, wherein the pH=8; the current density is 0.2A/dm 2; the temperature is 50 ℃ and the electroplating time is 4min.
The appearance diagram of comparative example 2 after the experiment is shown in fig. 6, and the comparative example 2 lacks the grain refiner compared with the example 2, so that the experimental result is that the roughness of the coating film is unqualified, and the appearance and the binding force are qualified;
Comparative example 3
Gold ion 10g/L, sodium sulfite 100g/L, sodium sulfate 15g/L, isodecyl alcohol and ethylene oxide polymer 10mg/L, 2 '-biquinoline-4, 4' -dicarboxylic acid disodium 15mg/L, 3-pyridine sulfonic acid 15mg/L, tetrazole violet 20mg/L, 3, 7-dimethyl-2, 6-octadienal 40mg/L, the balance deionized water, pH=8; the current density is 0.2A/dm 2; the temperature is 50 ℃ and the electroplating time is 4min.
As can be seen from the external appearance chart of the experiment of comparative example 3 shown in fig. 7, the comparative example 3 lacks the corrosion inhibitor compared with the example 2, and the plating layer is skinned and blackened due to the lack of the corrosion inhibitor, and the obtained experimental result is that the bonding force of the plating layer is not qualified and the plating leakage phenomenon exists.
Comparative example 4
Gold ion 10g/L, sodium sulfite 100g/L, sodium sulfate 15g/L, isodecyl alcohol and ethylene oxide polymer 10mg/L, 2 '-biquinoline-4, 4' -dicarboxylic acid disodium 15mg/L, 3-pyridine sulfonic acid 15mg/L, 2-benzyl imidazoline 0.5mg/L, tetrazole violet 20mg/L, and deionized water for the rest, wherein pH=8; the current density is 0.2A/dm 2; the temperature is 50 ℃ and the electroplating time is 4min.
As shown in fig. 8, the appearance of the experiment of comparative example 4 shows that the absence of the accelerator in comparative example 4 causes the peeling phenomenon of the plating layer compared with example 2, and the obtained experimental result is that the bonding force of the plating film is not acceptable and the plating leakage phenomenon exists.
The conclusion is drawn from the comparative examples and the specific examples: the complete plating solution component can obtain a plating layer without functional defects, and indeed, a certain functional component can cause different functional failures.
The above disclosure is only a few specific embodiments of the present invention, but the present invention is not limited thereto, and any changes that can be thought by those skilled in the art should fall within the protection scope of the present invention.
Claims (2)
1. The cyanide-free gold electroplating solution suitable for the nickel-gold structure process is characterized by comprising the following components in concentration: 3-14g/L of gold ion, 30-100g/L of complexing agent, 10-20g/L of inorganic salt, 10-30mg/L of surfactant, 10-40mg/L of grain refiner, 20-60mg/L of stabilizer, 30-60mg/L of accelerator and 0.5-1.5g/L of corrosion inhibitor; the surfactant is a nonionic surfactant of isodecyl alcohol and ethylene oxide polymer; the grain refiner is 2,2 '-biquinoline-4, 4' -dicarboxylic acid disodium and 3-pyridine sulfonic acid, and the mass concentration ratio of the two is 1:1 when in use; the corrosion inhibitor is 2-benzyl imidazoline;
the gold ions are provided by sodium gold sulfite; the inorganic salt is sodium sulfate; the promoter is 3, 7-dimethyl-2, 6-octadienal; the complexing agent is sodium sulfite; the pH value is between 7.5 and 9; the stabilizer is tetrazole violet.
2. A cyanide-free gold plating solution suitable for use in a nickel gold structure process according to claim 1 wherein the temperature is between 40-70 ℃.
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| CN115522238A (en) * | 2022-11-23 | 2022-12-27 | 深圳创智芯联科技股份有限公司 | Cyanide-free gold plating solution of sodium gold sulfite and plating process thereof |
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| CN115522238A (en) * | 2022-11-23 | 2022-12-27 | 深圳创智芯联科技股份有限公司 | Cyanide-free gold plating solution of sodium gold sulfite and plating process thereof |
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