WO2016098789A1 - Cyanogen-free gold electroplating liquid and gold electroplating method - Google Patents

Cyanogen-free gold electroplating liquid and gold electroplating method Download PDF

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WO2016098789A1
WO2016098789A1 PCT/JP2015/085138 JP2015085138W WO2016098789A1 WO 2016098789 A1 WO2016098789 A1 WO 2016098789A1 JP 2015085138 W JP2015085138 W JP 2015085138W WO 2016098789 A1 WO2016098789 A1 WO 2016098789A1
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gold plating
gold
group
plating solution
electrolytic
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PCT/JP2015/085138
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French (fr)
Japanese (ja)
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恒怡 馬
クリストファー コルドニエ
渉 竹花
麻里 佐藤
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株式会社Jcu
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Priority to JP2016564871A priority Critical patent/JP6591444B2/en
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    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00Electroplating: Baths therefor
    • C25D3/02Electroplating: Baths therefor from solutions
    • C25D3/48Electroplating: Baths therefor from solutions of gold

Definitions

  • the present invention relates to a nocyan electrolytic gold plating solution and a gold plating method.
  • Gold plating films have long been used not only for decorative purposes and tableware, but also because they have excellent chemical stability and electrical conductivity and low mechanical hardness. For example, bump electrode formation, wire bonding, solder balls It is also widely used in the electronic industry field such as bonding pad surface treatment.
  • the gold plating solutions used in the past were mostly cyanide solutions containing toxic potassium gold cyanide, but recently there are problems with work safety and wastewater treatment, and attacks on resists for semiconductor components, etc. Due to these problems, demands for non-cyanide gold plating solutions are increasing, and various nocyanide gold platings have been proposed.
  • a gold plating solution for example, there are many reports using gold (I) sodium sulfite as a gold salt (for example, Patent Documents 1 and 2).
  • Patent Document 3 a gold plating solution using a hydantoin derivative as a complexing agent has been reported.
  • the plating solution has low stability, the cost is high, and the performance of the film does not reach that of the cyan solution, practical use is limited. Therefore, it is desired to develop a practical nocyanide gold plating solution that is excellent in solution stability and has the same plating film characteristics as the cyan solution.
  • the electrolytic plating solution disclosed therein contains sodium chloroaurate, 6-aminopenicillanic acid, citric acid, bipyridyl, and PEG200, and although gold plating can be performed, the current efficiency, the deposited gold film It was not practical in terms of hardness, purity, precipitated crystal state, and the like.
  • the present inventors have made it a problem to provide a nocyan electrolytic gold plating solution that can be used in place of an electrolytic gold plating solution containing a cyanide compound that has been used so far.
  • the present inventors have obtained a practical non-cyanide electrolytic gold plating solution by combining a monovalent gold complex having a specific structure with an electrolyte and a metal crystal modifier.
  • the present invention has been completed.
  • the present invention provides the following components (a) to (c):
  • (A) Monovalent gold complex represented by the following general formula (I) (In the formula (I), R 1 represents hydrogen or a mercapto group which may be branched or optionally branched alkyl group 1 to 4; R 2 is hydrogen or branched.
  • R 3 represents an optionally substituted alkyl group having 1 to 4 carbon atoms, and R 3 may have hydrogen, an optionally branched alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, or a mercapto group. And optionally represents a carboxyalkyl group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10.)
  • the present invention is a method for the nocyan electrolysis gold plating of a member to be plated, characterized in that the member to be plated is electroplated in the above-mentioned nocyan electrolytic gold plating solution.
  • the non-cyanide electrolytic gold plating solution of the present invention is extremely stable, has not changed even for one year after preparation, and hardly changes the physical properties of the deposited gold or decomposes the gold plating solution during the gold plating operation.
  • the gold plating film obtained by the gold plating method using the non-cyanide gold plating solution of the present invention has a beautiful appearance, a dense crystal structure, and excellent solderability and wire bonding properties. Moreover, since the current efficiency of the present invention is 90% or more, it is practical. Moreover, according to the non-cyanide gold plating method of the present invention, it is possible to control the hardness, purity, crystal state, and the like of the gold plating obtained.
  • FIG. 4 is a diagram showing a polarization curve measured in Test Example 1.
  • FIG. 4 is a SEM photograph of a gold plating film deposited in Example 2.
  • 4 is a SEM photograph of a gold plating film deposited in Example 3.
  • 4 is a SEM photograph of a gold plating film deposited in Example 4.
  • 6 is a SEM photograph of gold bumps formed in Example 5. It is a figure which shows the result of the solder ball joint shear strength of test example 2, and the failure mode. It is a figure which shows the fracture
  • 4 is a SEM photograph of a gold plating film deposited in Example 7.
  • the non-cyanide gold plating solution does not contain a cyanide compound such as potassium gold cyanide used in conventional gold plating solutions.
  • R 1 is hydrogen or a mercapto group and may be branched or an alkyl group having 1 to 4 carbon atoms, preferably hydrogen, methyl group, ethyl group Propyl group, isopropyl group, butyl group, isobutyl group, mercaptomethyl group (—CH 2 —SH), more preferably hydrogen or methyl group.
  • R 2 is hydrogen or an optionally branched alkyl group having 1 to 4 carbon atoms, preferably hydrogen, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, more preferably hydrogen, Indicates a methyl group.
  • R 3 represents hydrogen, an optionally branched alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, or a mercapto group, and optionally branched carboxy group having 1 to 4 carbon atoms.
  • Alkyl group preferably hydrogen, methyl group, carboxymethyl group, carboxyethyl group, hydroxyethyl group, isocarboxyethyl group (—CH (CH 3 ) —COOH), mercaptocarboxymethyl group (—CH (SH) —COOH) 2-mercapto-isocarboxyethyl group (—CH (CH 2 SH) —COOH), more preferably a carboxymethyl group and hydrogen.
  • n represents an integer of 1 to 10, preferably an integer of 3 to 6, more preferably 4.
  • n represents the number of monomers formed of the monovalent gold complex.
  • the monovalent gold complex represented by the above general formula (I) is, for example, a trivalent gold aqueous solution containing tetrachloride gold (III) acid ion or a monovalent gold salt aqueous solution of sodium gold sulfite in the following general formula.
  • X represents hydrogen, ammonium ion or metal, preferably alkali metal such as sodium or potassium, alkaline earth metal such as calcium or magnesium, ammonium ion, silver, tin, antimony, germanium, lead
  • Bismuth cobalt, indium, mercury, nickel, zinc
  • R 1 to R 2 are the same as above
  • R 3 ′ is the same as R 3 above
  • an alkyl group, a hydroxyalkyl group or a carboxyalkyl group represented by R 3 wherein the above X (excluding hydrogen) is substituted with 1 to 5 moles of gold salt, preferably 3 Add to 3.5-fold mol, adjust the pH to 3 or less by adding an acidic substance if necessary, and then stir well. It can be prepared.
  • Examples of the compound represented by the general formula (II) include thiopronin, 2-mercaptoacetamide, N- (2-mercaptoethionyl) glycine, N- (2-mercaptoacetyl) glycine, N- (2-hydroxyethyl). ) -2-mercaptoacetamide or N- (2-mercapto-1-oxopropyl) glycine and sodium, potassium and tin salts thereof.
  • the trivalent gold aqueous solution containing the tetrachloride gold (III) acid ion described above can be prepared by, for example, dissolving gold in aqua regia or dissolving sodium chloroaurate sodium salt in pure water. it can.
  • the monovalent gold salt aqueous solution of sodium gold sulfite can be prepared by, for example, dissolving gold in aqua regia to bring the pH to 8 or more and reacting gold hydroxide to be separated with sodium sulfite. .
  • the acidic substance used for adjusting the pH is not particularly limited, and examples thereof include carboxylic acids such as acetic acid, citric acid, lactic acid, and tartaric acid, carbonic acid, and phosphoric acid.
  • the monovalent gold complex prepared as described above is prepared under the condition of pH 3 or less, it does not dissolve and becomes a precipitate. Therefore, the monovalent gold complex can be purified by a known purification means such as filtration using a membrane filter or the like, or centrifugation. Moreover, the purification degree can be increased by performing these purification means twice or more.
  • the monovalent gold complex obtained by filtration and centrifugation once is added to water, and the pH of this aqueous solution is adjusted to potassium hydroxide, sodium hydroxide or the like. An alkaline substance is added and adjusted to about 5 to dissolve the monovalent gold complex. Next, the above acidic substance is added to this aqueous solution to adjust the pH to 3 or less to reprecipitate the monovalent gold complex. By repeating this one or more times, the purity of the monovalent gold complex can be increased.
  • the monovalent gold complex prepared as described above may be used as it is.
  • a purified monovalent gold complex is added to water in an amount such that the gold ion is 50 to 100 g / L, and the pH of the aqueous solution is adjusted.
  • a syrup in which a monovalent gold complex is dissolved by adding an alkaline substance such as potassium hydroxide or sodium hydroxide to about pH 5 may be used.
  • the content of the monovalent gold complex of component (a) in the nocyan electrolytic gold plating solution of the present invention is not particularly limited, but is, for example, in the range of 2 to 30 g / L, preferably 4 to 16 g / L as gold ions. .
  • the amount of gold is less than 2 g / L, the deposition rate of gold is slow and may not be suitable for actual operation.
  • the amount exceeds 30 g / L the cost increases and industrial utility may be lost.
  • the electrolyte of the component (b) used in the non-cyanide gold plating solution of the present invention is not particularly limited, and examples thereof include potassium salts, sodium salts and ammonium salts of inorganic acids or organic acids.
  • examples of the inorganic acid or organic acid include sulfuric acid, formic acid, carbonic acid, nitric acid, phosphoric acid, citric acid, acetic acid, lactic acid, succinic acid, glycolic acid, and tartaric acid, with sulfuric acid or formic acid being preferred.
  • These electrolytes can be used alone or in combination of two or more.
  • the content of the component (b) electrolyte in the non-cyanide gold plating solution of the present invention is not particularly limited, but is, for example, 0.01 to 10 mol / L, preferably 0.1 to 1 mol / L. If the electrolyte is less than 0.01 mol / L, it may be difficult to ensure sufficient conductivity as a plating solution, and if it exceeds 10 mol / L, the effect as an electrolyte may not increase.
  • the crystal modifier selected from the metal of component (c) used in the nocyan electrolytic gold plating solution of the present invention is not particularly limited as long as it has a crystal adjusting action.
  • thallium, antimony, bismuth, and tin are preferable.
  • One or more kinds of crystal modifiers selected from these metals can be used.
  • the content of the crystal modifier selected from the metal of component (c) in the nocyan electrolytic gold plating solution of the present invention is not particularly limited, but is, for example, 1 to 1000 ppm, preferably 5 ppm to 100 ppm.
  • the nocyan electrolytic gold plating solution of the present invention further includes components (d) and (e).
  • (D) pH buffer (e) It is preferable to contain one or two selected from the group consisting of crystal modifiers selected from sulfur-containing compounds.
  • the pH buffering agent of the component (d) is not particularly limited as long as it has a pH buffering action, and examples thereof include inorganic acids, organic carboxylic acids, organic phosphoric acids, pyridinesulfonic acids and their potassium salts, sodium salts, An ammonium salt etc. are mentioned.
  • pH buffering agent examples include inorganic acids such as phosphoric acid, carbonic acid and boric acid, organic carboxylic acids such as ethylenediaminetetraacetic acid (EDTA), nitrosotriacetic acid (NTA), citric acid and tartaric acid, 1-hydroxyethane- Organic phosphoric acids such as 1,1-diphosphonic acid (HEDP), 1,1,1-nitrotris (methylphosphonic acid) (ATMP), ethylenediaminetetramethylenephosphonic acid (EDTMP), 3-pyridinesulfonic acid, 2-pyridinesulfonic acid Pyridinesulfonic acid such as 5-methyl-3-pyridinesulfonic acid and 4-hydroxypyridine-3-sulfonic acid, and potassium salts, sodium salts, ammonium salts thereof and the like, preferably EDTA.
  • pH buffering agents can be used alone or in combination of two or more.
  • the content of the pH buffering agent of component (d) in the non-cyanide electrolytic gold plating solution of the present invention is not particularly limited. For example, it is 0.5 to 10 mol, preferably 1 to 1 mol with respect to 1 mol of gold ions in the gold plating solution. 2 mmol.
  • the pH buffering agent of component (d) By adding the pH buffering agent of component (d), the pH of the solution becomes stable, so that the gold complex is stabilized and the deposition uniformity of plating is improved. And the external appearance of the obtained gold plating is brighter and precipitation becomes uniform. Furthermore, the stability of the liquid can be ensured even when plating is performed for a long time.
  • the crystal modifier selected from the sulfur-containing compound of the component (e) is not particularly limited as long as it is a sulfur-containing compound having a crystal adjusting action.
  • thiosulfuric acid and thiophosphoric acid and their potassium salts, sodium salts, ammonium Examples thereof include salts and organic compounds having both a mercapto group and a carboxy group.
  • these crystal modifiers selected from these sulfur-containing compounds thiosulfuric acid, thiosalicylic acid, thioglycolic acid, 4-mercaptobenzoic acid, and 3-mercaptopropionic acid are preferable, and thiosulfuric acid and thiosalicylic acid are preferable.
  • One or more crystal modifiers selected from these sulfur-containing compounds can be used.
  • the content of the crystal modifier selected from the sulfur-containing compound of the component (e) in the nocyan electrolytic gold plating solution of the present invention is not particularly limited, but is, for example, 0.0001 to 0.025 mol / L, preferably 0.001. ⁇ 0.01 mol / L.
  • a crystal modifier selected from the sulfur-containing compound of component (e) nanoholes are not recognized even in SEM observation of gold plating.
  • components such as surfactants, brighteners and other additives may be added to the nocyan electrolytic gold plating solution of the present invention within a range not impairing the effects of the present invention.
  • non-cyanide electrolytic gold plating solution of the present invention is a non-cyanide by adjusting the kind and amount of metal added as a crystal adjusting agent selected from the metals of component (c) and the pH of the non-cyanide gold plating solution. It can also be used as an electrolytic alloy plating solution.
  • the component (c) when thallium is added as the component (c) to the non-cyanide gold plating solution of the present invention, it is almost pure gold soft gold.
  • antimony when antimony is added as the component (c), pure gold is easily formed at 10 ppm and pH 7 or less, soft gold is formed, and a gold / antimony alloy is easily formed at 20 ppm and pH 7 or more, and the hardness is increased.
  • tin When tin is added, it becomes a gold / tin alloy.
  • the pH of the above-described nocyan electrolytic gold plating solution of the present invention is not particularly limited, but is, for example, 3 to 14, preferably 5 to 8.
  • an alkaline substance such as potassium hydroxide, sodium hydroxide, or ammonia, or an acidic substance such as sulfuric acid, citric acid, or acetic acid may be used as appropriate.
  • the non-cyanide gold plating solution of the present invention can be produced by adding the above components to water and stirring, and adjusting the pH as necessary.
  • the non-cyanide electrolytic gold plating solution of the present invention described above can be used for electrolytic gold plating.
  • electrolytic gold plating can be performed by electrolyzing a member to be plated in the nocyan electrolytic gold plating solution of the present invention.
  • the member to be plated used for the electrolytic gold plating is not particularly limited, and examples thereof include a wafer, a printed wiring board, a connector of an electronic component device, and a lead frame.
  • the raw material of these to-be-plated members is not specifically limited, For example, nickel, copper, gold
  • the conditions for electrolytic gold plating using the non-cyanide electrolytic gold plating solution of the present invention are not particularly limited.
  • the solution temperature is 20 to 80 ° C. and the current density is 0.1 to 6 A / dm 2 .
  • the plated member subjected to electrolytic gold plating as described above has a beautiful appearance, improved corrosion resistance, and excellent solderability and wire bonding. Moreover, since the gold purity of the film can be adjusted depending on the composition of the gold plating solution and the plating conditions, it is possible to control softness and hardness.
  • the monovalent gold complex obtained above was poured into water, potassium hydroxide was added to adjust the pH to 5, and the monovalent gold complex was dissolved. Subsequently, the pH was adjusted to 3 or lower again by the above operation to produce a precipitate, which was further purified by filtration. This operation was repeated twice, and finally a monovalent gold complex purified to a purity of 98% or more (confirmed by NMR) was obtained.
  • the monovalent gold complex purified as described above was poured into water and adjusted to pH 5 with potassium hydroxide to prepare a monovalent gold complex syrup containing 100 g / L of gold ions.
  • Reference example 2 Preparation of monovalent gold complex: An aqueous solution containing 0.05 M thiopronin and 0.05 M sodium gold sulfite was stirred at 20 ° C. for 10 hours to form a monovalent gold complex. By adjusting the pH of this aqueous solution to 3 or less with acetic acid, the produced monovalent gold complex was precipitated. Next, the monovalent gold complex was isolated by filtering the aqueous solution through a 0.4 ⁇ m membrane filter. The gold recovery rate in this operation was 99.9%.
  • Reference example 3 Preparation of electrolytic gold plating solution: An aqueous solution containing 50 ml / L of monovalent gold complex syrup prepared in Reference Example 1 (5 g / L as gold ion) and 65 g / L of tripotassium citrate monohydrate was prepared, and the pH of this aqueous solution was adjusted to potassium hydroxide. The solution adjusted to 7.2 was used as an electrolytic gold plating solution.
  • Electrolytic gold plating The copper test piece was subjected to generally known pretreatment such as electrolytic degreasing, soft etching, and acid treatment, and then electrolytic nickel plating was performed. Immediately thereafter, the electrolytic gold plating solution prepared in Reference Example 3 was used to perform gold plating on a test piece plated with nickel on copper. The size of the plated portion of the test piece was 2 cm ⁇ 2 cm, and the area of the anode was 1.5 to 2.0 times the plating area. The anode was an insoluble titanium anode with iridium oxide as a coating layer, and the distance from the test piece (as a cathode) was about 6 cm.
  • Electrolytic gold plating was performed for 2 minutes in a plating tank made of heat-resistant vinyl chloride having a capacity of 100 ml while maintaining a liquid temperature of 60 ° C. and stirring at a current density of 0.4 A / dm 2 .
  • the appearance after gold plating was gold. Further, when the gold plating was observed by SEM, it was a smooth surface having a regular shape. However, the cathode current efficiency (hereinafter referred to as current efficiency) in electrolytic gold plating was calculated from “actual precipitation amount / theoretical precipitation amount ⁇ 100%” and was 30%. Moreover, when plating was performed for a long time, it turned out that an external appearance tends to become red and the pH of a plating solution falls gradually.
  • Electrolytic gold plating An aqueous solution containing 40 ml / L of monovalent gold complex syrup prepared in Reference Example 1 (4 g / L as gold ions), 44 g / L of potassium sulfate, and 24.4 ppm of thallium formate (20 ppm as thallium ions) was prepared. The solution was adjusted to 6.2 with potassium hydroxide as an electrolytic gold plating solution.
  • Test example 1 Electrochemical measurement: Polarization curves obtained by electrochemical measurements of the electrolytic gold plating solution obtained in Example 1 (added with 20 ppm thallium) and the electrolytic gold plating solution prepared in Reference Example 3 (without adding thallium) are shown in FIG. It has been found that the addition of thallium, a metal as a crystal modifier, shifts the polarization curve to the right, making polarization much easier. The current efficiency of the electrolytic gold plating solution to which thallium was added was about 100%, which was about twice that of the electrolytic gold plating solution to which thallium was not added.
  • Electrolytic gold plating An aqueous solution containing 50 ml / L of monovalent gold complex syrup prepared in Reference Example 1 (5 g / L as gold ions), 42 g / L of potassium formate, 24.4 ppm of thallium formate (20 ppm as thallium ions), and 7.31 g / L of EDTA. A solution prepared by adjusting the pH of this aqueous solution to 7.4 with potassium hydroxide was used as an electrolytic gold plating solution.
  • the electrolytic gold plating solution was subjected to electrolytic gold plating in the same manner as in Reference Example 4. As a result, the appearance after gold plating was brighter than those obtained in Reference Example 4 and Example 1. When the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 90% or more. Furthermore, the pH of the plating solution was stable even after plating for a long time. However, when the gold plating film was observed with an SEM, nanoholes were slightly observed, although not as much as in Reference Example 4 (FIG. 2).
  • Example 3 Electrolytic gold plating: Monovalent gold complex syrup 50 ml / L prepared as in Reference Example 1 (5 g / L as gold ion), potassium formate 42 g / L, thallium formate 24.4 ppm (20 ppm as thallium ion), EDTA 7.31 g / L, thiosalicylic acid 1 An aqueous solution containing 0.54 g / L was prepared, and the pH of this aqueous solution was adjusted to 7.4 with potassium hydroxide to obtain an electrolytic gold plating solution.
  • the electrolytic gold plating solution was subjected to electrolytic gold plating in the same manner as in Reference Example 4. As a result, the appearance after gold plating was brighter than those obtained in Reference Example 4 and Example 2. When the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 95% or more. Further, when the gold plating film was observed by SEM, nanoholes observed in the gold plating film obtained in Example 2 were not recognized (FIG. 3).
  • the purity of the gold plating film obtained in Examples 1, 2, and 3 was confirmed by ICP analysis after dissolving the gold plating film with a gold release agent and found to be 99.9% or more. Therefore, it was found that the gold plating films obtained in Examples 1, 2, and 3 were pure gold. Further, when the hardness of the gold film was confirmed, the hardness of the gold plating film was measured with a load of 5 g using an MVK-G3 Vickers hardness tester (manufactured by AKASHI). The Vickers hardness of the gold plating films obtained in Examples 1, 2, and 3 is 110 HV or less, and is 60 to 70 HV after 30 minutes of annealing at 300 ° C., which is required for pure gold plating films of electronic products. It has been shown to have good performance.
  • Electrolytic gold plating Monovalent gold complex syrup prepared in Reference Example 1 40 ml / L (4 g / L as gold ion), 44 g / L potassium sulfate, potassium antimony tartrate (10 ppm as antimony ion), 7.31 g / L EDTA, 10 g trisodium citrate / L, an aqueous solution containing 0.77 g / L of thiosalicylic acid, and the pH of this aqueous solution adjusted to 6.2 with potassium hydroxide was used as the electrolytic gold plating solution.
  • Example 5 Micro bump formation: Using the electrolytic gold plating solution prepared in Example 4, bump plating of the semiconductor wafer was performed. Gold plating was performed on a resist-patterned wafer (plating base material was sputtering gold) at a current density of 0.4 A / dm 2 and a liquid temperature of 60 ° C. for 40 minutes. When the resist was peeled off after plating and the surface was observed, fine gold bumps (width: 10 ⁇ m, height: about 10 ⁇ m) as shown in FIG. 5 were formed. Since the gold bumps grew straight up, it was found that this electrolytic gold plating solution did not attack the resist.
  • Electrolytic gold plating Using an electrolytic pure gold plating solution SKYGOLD S-10 (manufactured by JCU) as a commercial product of cyan gold plating, the liquid temperature is 60 ° C., and the current density is 0.3 A / dm 2 for 2 minutes (thickness 0.35 ⁇ m). ) Electrolytic gold plating was performed.
  • Electrolytic gold plating Sodium gold sulfite (10 g / L as gold ion), sodium sulfite 80 g / L, thallium sulfate (20 ppm as thallium ion), ethylenediamine 10 g / L, EDTA 4 g / L, disodium hydrogen phosphate 20 g / L, 3,5-dinitro
  • An aqueous solution containing 1 g / L of benzoic acid was prepared, and the pH of this aqueous solution was adjusted to 8.0 with potassium hydroxide was used as an electrolytic gold plating solution. Using this liquid, electrolytic gold plating was performed for 70 seconds (film thickness 0.35 ⁇ m) while stirring at a liquid temperature of 60 ° C. and a current density of 0.5 A / dm 2 .
  • Test example 2 Physical property measurement: (1) Solder ball joint shear strength and fracture mode The solder ball joint shear strength and fracture mode of the gold plating films obtained with the solutions of Examples 3 and 4 and Comparative Examples 1 and 2 were compared (FIG. 6). Solder ball bondability was evaluated by M705 (Sn-3.0Ag-0.5Cu) 0.76mm ⁇ solder ball (manufactured by Senju Metal Industry), flux 529D (paste: Senju Metal Industry), and reflow RF- Use 430-M2 (manufactured by Pulse), solder at a top temperature of 260 ° C and a retention time of about 32 seconds above the melting point, and then use a bond tester 4000HS (manufactured by ARCTEK) to share at a shear rate of 40 mm / s.
  • M705 Sn-3.0Ag-0.5Cu
  • flux 529D paste: Senju Metal Industry
  • reflow RF- Use 430-M2 manufactured by Pulse
  • the film thickness of the gold plating evaluated was all (Ni 5.0 ⁇ m / Au 0.35 ⁇ m).
  • the fracture mode was evaluated by the ratio of the remaining area of the solder balls on the fracture surface. It was evaluated that the bondability was strong when there was no interfacial fracture and there were many remaining solder balls, and it was evaluated that the bondability was weak when there was no remaining solder balls and the interface was broken. As shown in FIG. 6, with 20 samples, the solder joint strengths of Example 3 and Example 4 of the present invention were equivalent to those of Comparative Example 1 and Comparative Example 2, and the fracture mode was almost free from interface fracture. . On the other hand, the cyan gold plating solution of Comparative Example 1 and the gold sulfite gold plating solution of Comparative Example 2 are slightly more likely to have a little solder residue, and there are cases of interface breakdown. There was nothing.
  • Wire bonding strength The wire bonding strengths of the gold plating films obtained with the solutions of Examples 3 and 4 and Comparative Examples 1 and 2 were compared. Wire bonding strength is measured by using a gold wire ⁇ 18 ⁇ m (manufactured by GMH), hitting and mounting the wire with bonder HW27U-HF (manufactured by Panasonic), and measuring pull strength using pull tester BT-14 (manufactured by DAGE). (Fracture modes (5 levels A to E) in the pull strength measurement are shown in FIG. 7. A and E fail). The film thickness of the gold plating evaluated was all (Ni 5.0 ⁇ m / Au 0.35 ⁇ m). The measurement results of Examples 3 and 4 and Comparative Examples 1 and 2 were all B (pass).
  • the gold plating solutions of Example 3 and Example 4 of the present invention are significantly different from the cyan gold plating solution of Comparative Example 1 and the gold sulfite gold plating solution of Comparative Example 2. Not as good.
  • the gold plating film obtained with the gold plating solutions of Examples 3 and 4 is almost the same as the gold plating film obtained with the cyan bath of Comparative Example 1 and the sulfite bath of Comparative Example 2 that have been used conventionally. It has the characteristics required for electrical components at or above. Therefore, it was found that the present invention can be used in place of an electrolytic gold plating solution containing a cyanide compound.
  • Electrolytic gold plating 50 ml / L of monovalent gold complex syrup prepared in Reference Example 1 (5 g / L as gold ion), 42 g / L of potassium formate, bismuth methanesulfonate (20 ppm as bismuth), 7.31 g / L of EDTA, and 0.1 mg of thioglycolic acid.
  • An aqueous solution containing 46 g / L was prepared, and the pH of this aqueous solution was adjusted to 7.4 with potassium hydroxide was used as an electrolytic gold plating solution.
  • Example 7 Electrolytic gold plating: An aqueous solution containing 50 ml / L of monovalent gold complex syrup prepared in Reference Example 1 (5 g / L as gold ions), 42 g / L of potassium formate, tin sulfate (100 ppm as tin), 5.8 g / L of EDTA, A solution prepared by adjusting the pH of this aqueous solution to 7.4 with potassium hydroxide was used as an electrolytic gold plating solution.
  • a test piece plated with nickel on copper was put into this electrolytic gold plating solution, and the mixture was lightly stirred at a liquid temperature of 60 ° C. and a current density of 1 A / dm 2 to perform electrolytic gold plating for 3 minutes.
  • the appearance after plating was bright and bright gold.
  • the surface morphology was fairly smooth, and the interface of crystal grains was not visible at all compared to Examples 3 and 4 (FIG. 9).
  • the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 40%.
  • the composition was a gold alloy of 99.4% gold and 0.6% tin.
  • Example 8 Electrolytic gold plating: Monovalent gold complex syrup prepared in Reference Example 1 80 ml / L (8 g / L as gold ion), potassium sulfate 44 g / L, tin sulfate (100 ppm as tin), EDTA 7.31 g / L, thiosalicylic acid 1.54 g / L An aqueous solution containing the solution was prepared, and the pH of this aqueous solution was adjusted to 7.4 with potassium hydroxide was used as the electrolytic gold plating solution.
  • the electrolytic gold plating solution was subjected to electrolytic gold plating in the same manner as in Reference Example 4. As a result, the appearance after gold plating was brighter than those obtained in Reference Example 4 and Example 1. When the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 90%. When the gold purity of the film was confirmed, the composition was a gold alloy of 99.2% gold and 0.8% tin.
  • Example 9 Preparation of electrolytic gold plating solution: An aqueous solution containing 0.15M 2-mercaptoacetamide and 0.05M chloroauric acid generated from the hydrolysis of 2,4-thiazolidinedione was stirred at 20 ° C. for 10 hours to form a monovalent gold complex. In addition, since the pH of this aqueous solution is 3 or less, the produced
  • Example 10 Electrolytic gold plating: An aqueous solution containing 0.15 M N- (2-mercaptoethionyl) glycine and 0.05 M chloroauric acid generated by hydrolysis of rhodanine-3-acetic acid was stirred at 20 ° C. for 10 hours to form a monovalent gold complex. It was. In addition, since the pH of this aqueous solution is 3 or less, the produced
  • the monovalent gold complex of the above formula (V) was made into a syrup in the same manner as in Reference Example 1, and this was replaced with the monovalent gold complex syrup used in Example 1 to prepare an electrolytic gold plating solution.
  • electrolytic gold plating is performed with this electrolytic gold plating solution, a similar gold plating film is obtained.
  • Example 11 Preparation of electrolytic gold plating solution :: An aqueous solution containing 0.15M N- (2-hydroxyethyl) -2-mercaptoacetamide and 0.05M chloroauric acid formed from the hydrolysis of 2,4-thiazolidinedione and 2-aminoethanol was stirred at 20 ° C. for 10 hours. And a monovalent gold complex was produced. In addition, since the pH of this aqueous solution is 3 or less, the produced
  • the non-cyanide electrolytic gold plating solution of the present invention is practical and can be used in place of the electrolytic gold plating solution containing a cyanide compound that has been used so far. more than

Abstract

Provided is a cyanogen-free gold electroplating liquid with which conventional gold electroplating liquids comprising cyanogen-based compounds can be replaced, the cyanogen-free gold electroplating liquid being characterized by containing components (a) through (c): (a) is a monovalent metal complex represented by general formula (I) (where in general formula (I), R1 is hydrogen or an optionally branched C1-4 alkyl group optionally having mercapto groups, R2 is hydrogen or an optionally branched C1-4 alkyl group, R3 is hydrogen, an optionally branched C1-4 alkyl group, a hydroxyalkyl group, or an optionally branched C1-4 carboxyalkyl group optionally having mercapto groups, and n is an integer of 1 to 10); (b) is an electrolyte; and (c) is a crystal modifier selected from metals.

Description

ノーシアン電解金めっき液および金めっき方法Norcyan electrolytic gold plating solution and gold plating method
 本発明は、ノーシアン電解金めっき液および金めっき方法に関する。 The present invention relates to a nocyan electrolytic gold plating solution and a gold plating method.
 金めっき膜は、古くから装飾用や食器などに用いられるだけでなく、化学的な安定性や電気伝導性に優れ、かつ機械的硬度が低いため、例えば、バンプ電極形成やワイヤボンディング、はんだボールボンディングパッドの表面処理等の電子工業分野においても広く利用されている。 Gold plating films have long been used not only for decorative purposes and tableware, but also because they have excellent chemical stability and electrical conductivity and low mechanical hardness. For example, bump electrode formation, wire bonding, solder balls It is also widely used in the electronic industry field such as bonding pad surface treatment.
 従来用いられていた金めっき液は、ほとんどが有毒なシアン化金カリウムを含んだシアン液であったが、最近では作業安全上或いは排水処理上の問題、また半導体部品のレジスト等をアタックする等の問題から、非シアン系の金めっき液の要求が高まっており、種々のノーシアン系金めっきが提案されている。このような金めっき液としては、例えば、亜硫酸金(I)ナトリウムを金塩として使用するものが多く報告されている(例えば、特許文献1および2)。 The gold plating solutions used in the past were mostly cyanide solutions containing toxic potassium gold cyanide, but recently there are problems with work safety and wastewater treatment, and attacks on resists for semiconductor components, etc. Due to these problems, demands for non-cyanide gold plating solutions are increasing, and various nocyanide gold platings have been proposed. As such a gold plating solution, for example, there are many reports using gold (I) sodium sulfite as a gold salt (for example, Patent Documents 1 and 2).
 しかし、亜硫酸金(I)ナトリウムを用いた金めっき液では、溶液中の亜硫酸イオンがアノードから発生する酸素や大気中の酸素により酸化され易く、自然に濃度が減少する。その結果、金めっき液中の金錯体の安定性が低下し、電析物の物性の変化やめっき液の分解が生ずるという不具合が生じていた。 However, in a gold plating solution using gold (I) sodium sulfite, sulfite ions in the solution are easily oxidized by oxygen generated from the anode or oxygen in the atmosphere, and the concentration naturally decreases. As a result, the stability of the gold complex in the gold plating solution was lowered, causing a problem that the physical properties of the electrodeposited material were changed and the plating solution was decomposed.
 また、別の金めっき液としては、例えば、ヒダントイン誘導体を錯化剤として使用した金めっき液も報告されている(特許文献3)。しかし、このめっき液は、液の安定性が低く、コストが高く、皮膜の性能もシアン液に及ばないため、実用化は限られている。従って、液安定性に優れた、めっき皮膜特性もシアン液と同等の実用的なノーシアン金めっき液の開発が望まれている。 Also, as another gold plating solution, for example, a gold plating solution using a hydantoin derivative as a complexing agent has been reported (Patent Document 3). However, since the plating solution has low stability, the cost is high, and the performance of the film does not reach that of the cyan solution, practical use is limited. Therefore, it is desired to develop a practical nocyanide gold plating solution that is excellent in solution stability and has the same plating film characteristics as the cyan solution.
 最近では、6-アミノペニシラン酸、チオプロニン等を錯化剤として使用し、1価の金錯体を得て、これを利用した金めっき液も報告されている(特許文献4)。しかし、そこで開示されている電解めっき液は、塩化金酸ナトリウム、6-アミノペニシラン酸、クエン酸、ビピリジル、PEG200を含有するものであり、金めっきはできるものの、電流効率、析出金皮膜の硬度、純度、析出結晶状態等の点から実用的なものではなかった。 Recently, a monovalent gold complex was obtained by using 6-aminopenicillanic acid, thiopronin or the like as a complexing agent, and a gold plating solution using this was also reported (Patent Document 4). However, the electrolytic plating solution disclosed therein contains sodium chloroaurate, 6-aminopenicillanic acid, citric acid, bipyridyl, and PEG200, and although gold plating can be performed, the current efficiency, the deposited gold film It was not practical in terms of hardness, purity, precipitated crystal state, and the like.
特開平11-61480号公報Japanese Patent Laid-Open No. 11-61480 特開2011-184734号公報JP 2011-184734 A 米国特許出願公開第2003/111353号明細書US Patent Application Publication No. 2003/111353 国際公開第2014/10301号International Publication No. 2014/10301
 そこで、本発明者らは、これまで使用されていたシアン系化合物を含む電解金めっき液に代えて使用することができるノーシアン電解金めっき液を提供することを課題とした。 Therefore, the present inventors have made it a problem to provide a nocyan electrolytic gold plating solution that can be used in place of an electrolytic gold plating solution containing a cyanide compound that has been used so far.
 本発明者らは、上記課題を解決するために鋭意研究した結果、特定の構造の1価金錯体と、電解質および金属結晶調整剤とを組み合わせることにより、実用的なノーシアン電解金めっき液が得られることを見出し、本発明を完成させた。 As a result of diligent research to solve the above-mentioned problems, the present inventors have obtained a practical non-cyanide electrolytic gold plating solution by combining a monovalent gold complex having a specific structure with an electrolyte and a metal crystal modifier. The present invention has been completed.
 すなわち、本発明は、以下の成分(a)~(c)
(a)下記一般式(I)で示される1価金錯体
Figure JPOXMLDOC01-appb-C000002
 
(ただし、式(I)中、Rは、水素またはメルカプト基を有していてもよく分岐していてもよい炭素数1~4のアルキル基を示し、Rは、水素または分岐していてもよい炭素数1~4のアルキル基を示し、Rは、水素、分岐していてもよい炭素数1~4のアルキル基、ヒドロキシアルキル基、またはメルカプト基を有していてもよく分岐していてもよい炭素数1~4のカルボキシアルキル基を示し、nは1~10の整数を示す。)
(b)電解質
(c)金属から選ばれる金属結晶調整剤
を含有することを特徴とするノーシアン電解金めっき液である。
That is, the present invention provides the following components (a) to (c):
(A) Monovalent gold complex represented by the following general formula (I)
Figure JPOXMLDOC01-appb-C000002

(In the formula (I), R 1 represents hydrogen or a mercapto group which may be branched or optionally branched alkyl group 1 to 4; R 2 is hydrogen or branched. R 3 represents an optionally substituted alkyl group having 1 to 4 carbon atoms, and R 3 may have hydrogen, an optionally branched alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, or a mercapto group. And optionally represents a carboxyalkyl group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10.)
(B) Electrolyte (c) A non-cyanide gold plating solution containing a metal crystal modifier selected from metals.
 また、本発明は、被めっき部材を、上記ノーシアン電解金めっき液中で電解めっきすることを特徴とする被めっき部材のノーシアン電解金めっき方法である。 Further, the present invention is a method for the nocyan electrolysis gold plating of a member to be plated, characterized in that the member to be plated is electroplated in the above-mentioned nocyan electrolytic gold plating solution.
 本発明のノーシアン電解金めっき液は、安定性に極めて優れ、調製後1年間も変化がなく、金めっき作業中に析出金の物性の変化や金めっき液の分解を起こしにくい。 The non-cyanide electrolytic gold plating solution of the present invention is extremely stable, has not changed even for one year after preparation, and hardly changes the physical properties of the deposited gold or decomposes the gold plating solution during the gold plating operation.
 また、本発明のノーシアン電解金めっき液を用いた金めっき方法により得られる金めっき皮膜は、外観が美しく、結晶構造は緻密で、はんだ接合性とワイヤボンディング性も優れている。また、本発明の電流効率は90%以上であるため、実用的なものである。また、本発明のノーシアン電解金めっき方法によれば、得られる金めっきの硬度、純度、結晶状態等の制御も可能である。 Also, the gold plating film obtained by the gold plating method using the non-cyanide gold plating solution of the present invention has a beautiful appearance, a dense crystal structure, and excellent solderability and wire bonding properties. Moreover, since the current efficiency of the present invention is 90% or more, it is practical. Moreover, according to the non-cyanide gold plating method of the present invention, it is possible to control the hardness, purity, crystal state, and the like of the gold plating obtained.
試験例1で測定された分極曲線を示す図である。4 is a diagram showing a polarization curve measured in Test Example 1. FIG. 実施例2で析出した金めっき皮膜のSEM写真である。4 is a SEM photograph of a gold plating film deposited in Example 2. 実施例3で析出した金めっき皮膜のSEM写真である。4 is a SEM photograph of a gold plating film deposited in Example 3. 実施例4で析出した金めっき皮膜のSEM写真である。4 is a SEM photograph of a gold plating film deposited in Example 4. 実施例5で形成した金バンプのSEM写真である。6 is a SEM photograph of gold bumps formed in Example 5. 試験例2のはんだボール接合シェア強度と破壊モードの結果を示す図である。It is a figure which shows the result of the solder ball joint shear strength of test example 2, and the failure mode. ワイヤボンディングプル強度測定における破壊モードを示す図である。It is a figure which shows the fracture | rupture mode in wire bonding pull strength measurement. 試験例2のワイヤボンディング強度の結果を示す図である。It is a figure which shows the result of the wire bonding strength of Test Example 2. 実施例7で析出した金めっき皮膜のSEM写真である。4 is a SEM photograph of a gold plating film deposited in Example 7.
 本明細書において、ノーシアン電解金めっき液とは、従来の金めっき液に用いられていたシアン化金カリウム等のシアン系化合物を含有しないものである。 In this specification, the non-cyanide gold plating solution does not contain a cyanide compound such as potassium gold cyanide used in conventional gold plating solutions.
 本発明のノーシアン電解金めっき液に用いられる成分(a)の下記一般式(I)
Figure JPOXMLDOC01-appb-C000003
 
で示される1価金錯体であって、Rは、水素またはメルカプト基を有していてもよく分岐していてもよい炭素数1~4のアルキル基、好ましくは水素、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、メルカプトメチル基(-CH-SH)、より好ましくは水素、メチル基を示す。また、Rは、水素または分岐していてもよい炭素数1~4のアルキル基、好ましくは水素、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、より好ましくは水素、メチル基を示す。更に、Rは、水素、分岐していてもよい炭素数1~4のアルキル基、ヒドロキシアルキル基、またはメルカプト基を有していてもよく分岐していてもよい炭素数1~4のカルボキシアルキル基、好ましくは水素、メチル基、カルボキシメチル基、カルボキシエチル基、ヒドロキシエチル基、イソカルボキシエチル基(-CH(CH)-COOH)、メルカプトカルボキシメチル基(-CH(SH)-COOH)、2-メルカプト-イソカルボキシエチル基(-CH(CHSH)-COOH)、より好ましくはカルボキシメチル基、水素を示す。また更に、nは1~10の整数、好ましくは3~6の整数、より好ましくは4を示す。なお、ここでnは1価金錯体が何量体で形成されているかを示す。
The following general formula (I) of the component (a) used in the nocyan electrolytic gold plating solution of the present invention
Figure JPOXMLDOC01-appb-C000003

In which R 1 is hydrogen or a mercapto group and may be branched or an alkyl group having 1 to 4 carbon atoms, preferably hydrogen, methyl group, ethyl group Propyl group, isopropyl group, butyl group, isobutyl group, mercaptomethyl group (—CH 2 —SH), more preferably hydrogen or methyl group. R 2 is hydrogen or an optionally branched alkyl group having 1 to 4 carbon atoms, preferably hydrogen, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, more preferably hydrogen, Indicates a methyl group. Further, R 3 represents hydrogen, an optionally branched alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, or a mercapto group, and optionally branched carboxy group having 1 to 4 carbon atoms. Alkyl group, preferably hydrogen, methyl group, carboxymethyl group, carboxyethyl group, hydroxyethyl group, isocarboxyethyl group (—CH (CH 3 ) —COOH), mercaptocarboxymethyl group (—CH (SH) —COOH) 2-mercapto-isocarboxyethyl group (—CH (CH 2 SH) —COOH), more preferably a carboxymethyl group and hydrogen. Furthermore, n represents an integer of 1 to 10, preferably an integer of 3 to 6, more preferably 4. Here, n represents the number of monomers formed of the monovalent gold complex.
 上記した一般式(I)で示される1価金錯体は、例えば、テトラクロリド金(III)酸イオンを含有する3価金の水溶液または亜硫酸金ナトリウムの1価の金塩水溶液に、下記一般式(II)
Figure JPOXMLDOC01-appb-C000004
 
で示される化合物(ただし、Xは水素、アンモニウムイオン、金属を示し、好ましくはナトリウム、カリウム等のアルカリ金属、カルシウム、マグネシウム等のアルカリ土類金属、アンモニウムイオン、銀、スズ、アンチモン、ゲルマニウム、鉛、ビスマス、コバルト、インジウム、水銀、ニッケル、亜鉛、より好ましくは水素、ナトリウム、カリウムを示す。また、R~Rは上記と同じものを示し、R’は、上記Rと同じものか、上記Rのアルキル基、ヒドロキシアルキル基、カルボキシアルキル基の水素が、上記X(ただし、水素を除く)に置換されたものを示す。)を金塩の1~5倍モル好ましくは3~3.5倍モルとなるように添加し、必要により酸性物質を添加してpHを3以下に調整した後、十分攪拌することにより調製することができる。
The monovalent gold complex represented by the above general formula (I) is, for example, a trivalent gold aqueous solution containing tetrachloride gold (III) acid ion or a monovalent gold salt aqueous solution of sodium gold sulfite in the following general formula. (II)
Figure JPOXMLDOC01-appb-C000004

(Wherein X represents hydrogen, ammonium ion or metal, preferably alkali metal such as sodium or potassium, alkaline earth metal such as calcium or magnesium, ammonium ion, silver, tin, antimony, germanium, lead) Bismuth, cobalt, indium, mercury, nickel, zinc, more preferably hydrogen, sodium, potassium, R 1 to R 2 are the same as above, and R 3 ′ is the same as R 3 above Or an alkyl group, a hydroxyalkyl group or a carboxyalkyl group represented by R 3 , wherein the above X (excluding hydrogen) is substituted with 1 to 5 moles of gold salt, preferably 3 Add to 3.5-fold mol, adjust the pH to 3 or less by adding an acidic substance if necessary, and then stir well. It can be prepared.
 前記一般式(II)で示される化合物としては、例えば、チオプロニン、2-メルカプトアセトアミド、N-(2-メルカプトエチオニル)グリシン、N-(2-メルカプトアセチル)グリシン、N-(2-ヒドロキシエチル)-2-メルカプトアセトアミド、または、N-(2-メルカプト-1-オキソプロピル)グリシンおよびこれらのナトリウム塩、カリウム塩、スズ塩等が挙げられる。 Examples of the compound represented by the general formula (II) include thiopronin, 2-mercaptoacetamide, N- (2-mercaptoethionyl) glycine, N- (2-mercaptoacetyl) glycine, N- (2-hydroxyethyl). ) -2-mercaptoacetamide or N- (2-mercapto-1-oxopropyl) glycine and sodium, potassium and tin salts thereof.
 上記したテトラクロリド金(III)酸イオンを含有する3価金の水溶液は、例えば、王水に金を溶解させたり、塩化金酸ナトリウムソーダを純水に溶解させたりすることにより調製することができる。また、亜硫酸金ナトリウムの1価の金塩水溶液は、例えば、王水に金を溶解して、pHを8以上にして、分離する水酸化金と亜硫酸ナトリウムを反応させることにより調製することができる。 The trivalent gold aqueous solution containing the tetrachloride gold (III) acid ion described above can be prepared by, for example, dissolving gold in aqua regia or dissolving sodium chloroaurate sodium salt in pure water. it can. Moreover, the monovalent gold salt aqueous solution of sodium gold sulfite can be prepared by, for example, dissolving gold in aqua regia to bring the pH to 8 or more and reacting gold hydroxide to be separated with sodium sulfite. .
 また、pHの調整に用いられる酸性物質は特に限定されないが、例えば、酢酸、クエン酸、乳酸、酒石酸等のカルボン酸、炭酸、リン酸等が挙げられる。 The acidic substance used for adjusting the pH is not particularly limited, and examples thereof include carboxylic acids such as acetic acid, citric acid, lactic acid, and tartaric acid, carbonic acid, and phosphoric acid.
 上記のようにして調製される1価金錯体は、pHが3以下の条件で調製されているため溶解せずに沈殿物となる。そのため、1価金錯体は、メンブレンフィルター等を用いたろ過、遠心分離等の公知の精製手段で精製することができる。また、これらの精製手段は2回以上行うことで、精製度を高めることができる。 Since the monovalent gold complex prepared as described above is prepared under the condition of pH 3 or less, it does not dissolve and becomes a precipitate. Therefore, the monovalent gold complex can be purified by a known purification means such as filtration using a membrane filter or the like, or centrifugation. Moreover, the purification degree can be increased by performing these purification means twice or more.
 1価金錯体の精製度を高めるには、例えば、1回ろ過、遠心分離を行って得られた1価金錯体を水に投入し、この水溶液のpHを水酸化カリウム、水酸化ナトリウム等のアルカリ性物質を添加して5程度に調整して1価金錯体を溶解する。次に、この水溶液に上記酸性物質を添加してpHを3以下に調整して1価金錯体を再沈殿させる。これを1回以上繰り返すことにより1価金錯体の精製度を高くすることができる。 In order to increase the degree of purification of the monovalent gold complex, for example, the monovalent gold complex obtained by filtration and centrifugation once is added to water, and the pH of this aqueous solution is adjusted to potassium hydroxide, sodium hydroxide or the like. An alkaline substance is added and adjusted to about 5 to dissolve the monovalent gold complex. Next, the above acidic substance is added to this aqueous solution to adjust the pH to 3 or less to reprecipitate the monovalent gold complex. By repeating this one or more times, the purity of the monovalent gold complex can be increased.
 上記のようにして調製される1価金錯体は、そのままでも良いし、例えば、精製した1価金錯体を金イオンが50~100g/Lとなる量で水に投入し、この水溶液のpHを水酸化カリウム、水酸化ナトリウム等のアルカリ性物質を添加してpH5程度に調整して1価金錯体を溶解させたシロップとしておいてもよい。 The monovalent gold complex prepared as described above may be used as it is. For example, a purified monovalent gold complex is added to water in an amount such that the gold ion is 50 to 100 g / L, and the pH of the aqueous solution is adjusted. A syrup in which a monovalent gold complex is dissolved by adding an alkaline substance such as potassium hydroxide or sodium hydroxide to about pH 5 may be used.
 本発明のノーシアン電解金めっき液における、成分(a)の1価金錯体の含有量は、特に限定されないが、例えば、金イオンとして2~30g/L、好ましく4~16g/Lの範囲である。金が2g/Lより少ない場合、金の析出速度が遅く実際の操業に適さないことがあり、30g/Lを超えた場合、コストが高くなって、工業実用性がなくなることがある。 The content of the monovalent gold complex of component (a) in the nocyan electrolytic gold plating solution of the present invention is not particularly limited, but is, for example, in the range of 2 to 30 g / L, preferably 4 to 16 g / L as gold ions. . When the amount of gold is less than 2 g / L, the deposition rate of gold is slow and may not be suitable for actual operation. When the amount exceeds 30 g / L, the cost increases and industrial utility may be lost.
 また、本発明のノーシアン電解金めっき液に用いられる成分(b)の電解質は、特に限定されないが、例えば、無機酸または有機酸のカリウム塩、ナトリウム塩、アンモニウム塩等が挙げられる。前記無機酸または有機酸としては、例えば、硫酸、ギ酸、炭酸、硝酸、リン酸、クエン酸、酢酸、乳酸、コハク酸、グリコール酸、酒石酸等が挙げられ、好ましくは硫酸またはギ酸である。これら電解質は1種または2種以上を用いることができる。 Further, the electrolyte of the component (b) used in the non-cyanide gold plating solution of the present invention is not particularly limited, and examples thereof include potassium salts, sodium salts and ammonium salts of inorganic acids or organic acids. Examples of the inorganic acid or organic acid include sulfuric acid, formic acid, carbonic acid, nitric acid, phosphoric acid, citric acid, acetic acid, lactic acid, succinic acid, glycolic acid, and tartaric acid, with sulfuric acid or formic acid being preferred. These electrolytes can be used alone or in combination of two or more.
 本発明のノーシアン電解金めっき液における、成分(b)の電解質の含有量は、特に限定されないが、例えば、0.01~10mol/L、好ましくは0.1~1mol/Lである。電解質が0.01mol/Lより少ない場合、めっき液として十分な導電性を確保することが困難であることがあり、10mol/Lを超えた場合、電解質としての効果は増大しないことがある。 The content of the component (b) electrolyte in the non-cyanide gold plating solution of the present invention is not particularly limited, but is, for example, 0.01 to 10 mol / L, preferably 0.1 to 1 mol / L. If the electrolyte is less than 0.01 mol / L, it may be difficult to ensure sufficient conductivity as a plating solution, and if it exceeds 10 mol / L, the effect as an electrolyte may not increase.
 更に、本発明のノーシアン電解金めっき液に用いられる成分(c)の金属から選ばれる結晶調整剤は、結晶調整作用を有する金属であれば特に限定されないが、例えば、タリウム、アンチモン、ヒ素、ビスマス、スズ、鉛、インジウム、テルル、セリウム、セレン、コバルト、ニッケル等の金属が挙げられる。これらの中でも、好ましくはタリウム、アンチモン、ビスマス、スズである。これら金属から選ばれる結晶調整剤は1種または2種以上を用いることができる。また、金属から選ばれる結晶調整剤は、本発明のノーシアン電解金めっき液に、ギ酸、硫酸、酒石酸、メタンスルホン酸等の金属塩として添加することが好ましい。 Further, the crystal modifier selected from the metal of component (c) used in the nocyan electrolytic gold plating solution of the present invention is not particularly limited as long as it has a crystal adjusting action. For example, thallium, antimony, arsenic, bismuth , Tin, lead, indium, tellurium, cerium, selenium, cobalt, nickel and the like. Of these, thallium, antimony, bismuth, and tin are preferable. One or more kinds of crystal modifiers selected from these metals can be used. Moreover, it is preferable to add the crystal modifier selected from a metal as metal salts, such as formic acid, a sulfuric acid, tartaric acid, and methanesulfonic acid, to the nocyan electrolytic gold plating solution of this invention.
 本発明のノーシアン電解金めっき液における、成分(c)の金属から選ばれる結晶調整剤の含有量は特に限定されないが、例えば、1~1000ppm、好ましくは5ppm~100ppmである。 The content of the crystal modifier selected from the metal of component (c) in the nocyan electrolytic gold plating solution of the present invention is not particularly limited, but is, for example, 1 to 1000 ppm, preferably 5 ppm to 100 ppm.
 本発明のノーシアン電解金めっき液は、上記成分(a)~(c)に加えて更に、成分(d)および(e)
(d)pH緩衝剤
(e)硫黄含有化合物から選ばれる結晶調整剤
からなる群から選ばれる1種または2種を含有させることが好ましい。
In addition to the components (a) to (c), the nocyan electrolytic gold plating solution of the present invention further includes components (d) and (e).
(D) pH buffer (e) It is preferable to contain one or two selected from the group consisting of crystal modifiers selected from sulfur-containing compounds.
 上記成分(d)のpH緩衝剤は、pH緩衝作用を有するものであれば特に限定されないが、例えば、無機酸、有機カルボン酸、有機リン酸、ピリジンスルホン酸およびこれらのカリウム塩、ナトリウム塩、アンモニウム塩等が挙げられる。前記pH緩衝剤としては、例えば、リン酸、炭酸、ホウ酸等の無機酸、エチレンジアミン四酢酸(EDTA)、ニトロソ三酢酸(NTA)、クエン酸、酒石酸等の有機カルボン酸、1-ヒドロキシエタン-1,1-ジホスホン酸(HEDP)、1,1,1-ニトロトリス(メチルホスホン酸)(ATMP)、エチレンジアミン四メチレンホスホン酸(EDTMP)等の有機リン酸、3-ピリジンスルホン酸、2-ピリジンスルホン酸、5-メチル-3-ピリジンスルホン酸、4-ヒドロキシピリジン-3-スルホン酸等のピリジンスルホン酸、およびこれらのカリウム塩、ナトリウム塩、アンモニウム塩等が挙げられ、好ましくはEDTAである。これらpH緩衝剤は1種または2種以上を用いることができる。 The pH buffering agent of the component (d) is not particularly limited as long as it has a pH buffering action, and examples thereof include inorganic acids, organic carboxylic acids, organic phosphoric acids, pyridinesulfonic acids and their potassium salts, sodium salts, An ammonium salt etc. are mentioned. Examples of the pH buffering agent include inorganic acids such as phosphoric acid, carbonic acid and boric acid, organic carboxylic acids such as ethylenediaminetetraacetic acid (EDTA), nitrosotriacetic acid (NTA), citric acid and tartaric acid, 1-hydroxyethane- Organic phosphoric acids such as 1,1-diphosphonic acid (HEDP), 1,1,1-nitrotris (methylphosphonic acid) (ATMP), ethylenediaminetetramethylenephosphonic acid (EDTMP), 3-pyridinesulfonic acid, 2-pyridinesulfonic acid Pyridinesulfonic acid such as 5-methyl-3-pyridinesulfonic acid and 4-hydroxypyridine-3-sulfonic acid, and potassium salts, sodium salts, ammonium salts thereof and the like, preferably EDTA. These pH buffering agents can be used alone or in combination of two or more.
 本発明のノーシアン電解金めっき液における、成分(d)のpH緩衝剤の含有量は特に限定されないが、例えば、金めっき液中の金イオン1molに対して0.5~10mol、好ましくは1~2mmolである。なお、この成分(d)のpH緩衝剤を添加することにより、液のpHが安定になるため金錯体が安定し、めっきの析出均一性が改善される。そして、得られる金めっきの外観はより明るく、析出は均一になる。更に、長時間めっきを行う場合であっても液の安定性を確保することができる。 The content of the pH buffering agent of component (d) in the non-cyanide electrolytic gold plating solution of the present invention is not particularly limited. For example, it is 0.5 to 10 mol, preferably 1 to 1 mol with respect to 1 mol of gold ions in the gold plating solution. 2 mmol. By adding the pH buffering agent of component (d), the pH of the solution becomes stable, so that the gold complex is stabilized and the deposition uniformity of plating is improved. And the external appearance of the obtained gold plating is brighter and precipitation becomes uniform. Furthermore, the stability of the liquid can be ensured even when plating is performed for a long time.
 上記成分(e)の硫黄含有化合物から選ばれる結晶調整剤は、結晶調整作用を有する硫黄含有化合物であれば特に限定されないが、例えば、チオ硫酸ならびにチオリン酸およびこれらのカリウム塩、ナトリウム塩、アンモニウム塩、メルカプト基とカルボキシ基の両方を有する有機化合物等が挙げられる。これら硫黄含有化合物から選ばれる結晶調整剤の中でも、チオ硫酸、チオサリチル酸、チオグリコール酸、4-メルカプト安息香酸、3-メルカプトプロピオン酸が好ましく、チオ硫酸、チオサリチル酸が好ましい。これら硫黄含有化合物から選ばれる結晶調整剤は1種または2種以上を用いることができる。 The crystal modifier selected from the sulfur-containing compound of the component (e) is not particularly limited as long as it is a sulfur-containing compound having a crystal adjusting action. For example, thiosulfuric acid and thiophosphoric acid and their potassium salts, sodium salts, ammonium Examples thereof include salts and organic compounds having both a mercapto group and a carboxy group. Among these crystal modifiers selected from these sulfur-containing compounds, thiosulfuric acid, thiosalicylic acid, thioglycolic acid, 4-mercaptobenzoic acid, and 3-mercaptopropionic acid are preferable, and thiosulfuric acid and thiosalicylic acid are preferable. One or more crystal modifiers selected from these sulfur-containing compounds can be used.
 本発明のノーシアン電解金めっき液における、成分(e)の硫黄含有化合物から選ばれる結晶調整剤の含有量は特に限定されないが、例えば、0.0001~0.025mol/L、好ましくは0.001~0.01mol/Lである。なお、この成分(e)の硫黄含有化合物から選ばれる結晶調整剤を添加することにより、金めっきのSEM観察においてもナノホールが認められなくなる。 The content of the crystal modifier selected from the sulfur-containing compound of the component (e) in the nocyan electrolytic gold plating solution of the present invention is not particularly limited, but is, for example, 0.0001 to 0.025 mol / L, preferably 0.001. ~ 0.01 mol / L. In addition, by adding a crystal modifier selected from the sulfur-containing compound of component (e), nanoholes are not recognized even in SEM observation of gold plating.
 更に、本発明のノーシアン電解金めっき液には、本発明の効果を損なわない範囲で、界面活性剤、光沢剤、他の添加剤等の成分を添加してもよい。 Furthermore, components such as surfactants, brighteners and other additives may be added to the nocyan electrolytic gold plating solution of the present invention within a range not impairing the effects of the present invention.
 また更に、本発明のノーシアン電解金めっき液は、成分(c)の金属から選ばれる結晶調整剤として添加される金属の種類や添加量、ノーシアン電解金めっき液のpHを調整することによって、ノーシアン電解合金めっき液とすることもできる。 Still further, the non-cyanide electrolytic gold plating solution of the present invention is a non-cyanide by adjusting the kind and amount of metal added as a crystal adjusting agent selected from the metals of component (c) and the pH of the non-cyanide gold plating solution. It can also be used as an electrolytic alloy plating solution.
 具体的に、本発明のノーシアン電解金めっき液に、例えば、成分(c)としてタリウムを添加する場合、殆ど純金の軟質金となる。一方、成分(c)としてアンチモンを添加する場合、10ppmおよびpH7以下で純金形成しやすく、軟質金となり、20ppm及びpH7以上で金/アンチモン合金が形成しやすく、硬度も高くなる。スズを添加する場合、金/スズ合金となる。 Specifically, for example, when thallium is added as the component (c) to the non-cyanide gold plating solution of the present invention, it is almost pure gold soft gold. On the other hand, when antimony is added as the component (c), pure gold is easily formed at 10 ppm and pH 7 or less, soft gold is formed, and a gold / antimony alloy is easily formed at 20 ppm and pH 7 or more, and the hardness is increased. When tin is added, it becomes a gold / tin alloy.
 上記した本発明のノーシアン電解金めっき液のpHは特に限定されないが、例えば、3~14、好ましくは5~8である。pHの調整には、水酸化カリウム、水酸化ナトリウム、アンモニア等のアルカリ性物質、硫酸、クエン酸、酢酸等の酸性物質を適宜用いればよい。 The pH of the above-described nocyan electrolytic gold plating solution of the present invention is not particularly limited, but is, for example, 3 to 14, preferably 5 to 8. For pH adjustment, an alkaline substance such as potassium hydroxide, sodium hydroxide, or ammonia, or an acidic substance such as sulfuric acid, citric acid, or acetic acid may be used as appropriate.
 本発明のノーシアン電解金めっき液は、上記した成分を水に添加して撹拌し、必要によりpHを調整することにより製造することができる。 The non-cyanide gold plating solution of the present invention can be produced by adding the above components to water and stirring, and adjusting the pH as necessary.
 以上説明した本発明のノーシアン電解金めっき液は、電解金めっきに用いることができる。具体的に電解金めっきは、被めっき部材を、本発明のノーシアン電解金めっき液中で電解することにより行うことができる。この電解金めっきに用いられる被めっき部材は特に限定されないが、例えば、ウェハー、プリント配線板、電子部品デバイスのコネクタ、リードフレーム等である。これら被めっき部材の素材は特に限定されないが、例えば、ニッケル、銅、金等が挙げられる。 The non-cyanide electrolytic gold plating solution of the present invention described above can be used for electrolytic gold plating. Specifically, electrolytic gold plating can be performed by electrolyzing a member to be plated in the nocyan electrolytic gold plating solution of the present invention. The member to be plated used for the electrolytic gold plating is not particularly limited, and examples thereof include a wafer, a printed wiring board, a connector of an electronic component device, and a lead frame. Although the raw material of these to-be-plated members is not specifically limited, For example, nickel, copper, gold | metal | money etc. are mentioned.
 また、本発明のノーシアン電解金めっき液を用いた電解金めっきの条件は特に限定されず、例えば、液温20~80℃で、電流密度0.1~6A/dmである。 The conditions for electrolytic gold plating using the non-cyanide electrolytic gold plating solution of the present invention are not particularly limited. For example, the solution temperature is 20 to 80 ° C. and the current density is 0.1 to 6 A / dm 2 .
 上記のようにして電解金めっきが施された被めっき部材は、外観が美しく、耐腐食性が向上されて、はんだ接合性とワイヤボンディング性も優れている。また、金めっき液の組成やめっき条件により、皮膜の金純度の調整ができるため、軟質、硬質等の制御も可能となる。 The plated member subjected to electrolytic gold plating as described above has a beautiful appearance, improved corrosion resistance, and excellent solderability and wire bonding. Moreover, since the gold purity of the film can be adjusted depending on the composition of the gold plating solution and the plating conditions, it is possible to control softness and hardness.
 以下、本発明を実施例を挙げて詳細に説明するが、本発明はこれら実施例に何ら限定されるものではない。 Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.
参 考 例 1
   1価金錯体シロップの調製:
 チオプロニン0.15M、酢酸0.50Mおよび塩化金酸ナトリウム0.05Mを含む水溶液を20℃で10時間攪拌し、1価金錯体を生成させた。なお、この水溶液のpHは3以下であるため、生成した1価金錯体は溶解せず微粒子となっている。次に、この水溶液を0.4μmのメンブレンフィルターでろ過することにより、1価金錯体を単離した。この操作における金の回収率は99.9%であった。なお、この1価金錯体の構造は下記式(III)のような4量体構造であることは既に知られている(Carrie A. Simpson et al., Inorganic Chemistry 2010, 49(23), 10858-10866)。
Reference example 1
Preparation of monovalent gold complex syrup:
An aqueous solution containing 0.15M thiopronin, 0.50M acetic acid and 0.05M sodium chloroaurate was stirred at 20 ° C for 10 hours to form a monovalent gold complex. In addition, since the pH of this aqueous solution is 3 or less, the produced | generated monovalent gold complex does not melt | dissolve but is a microparticle. Next, this aqueous solution was filtered with a 0.4 μm membrane filter to isolate a monovalent gold complex. The gold recovery rate in this operation was 99.9%. It is already known that the structure of this monovalent gold complex is a tetramer structure represented by the following formula (III) (Carrie A. Simpson et al., Inorganic Chemistry 2010, 49 (23), 10858 -10866).
Figure JPOXMLDOC01-appb-C000005
 
Figure JPOXMLDOC01-appb-C000005
 
 上記で得られた1価金錯体を水に投入し、水酸化カリウムを添加して、pH5に調整することにより1価金錯体を溶解した。次いで、再び前記の操作でpH3以下に調整して沈殿を生成させ、更にろ過することにより精製した。この操作を2回繰り返し、最終的に純度が98%以上(NMRにて確認)まで精製された1価金錯体が得られた。 The monovalent gold complex obtained above was poured into water, potassium hydroxide was added to adjust the pH to 5, and the monovalent gold complex was dissolved. Subsequently, the pH was adjusted to 3 or lower again by the above operation to produce a precipitate, which was further purified by filtration. This operation was repeated twice, and finally a monovalent gold complex purified to a purity of 98% or more (confirmed by NMR) was obtained.
 上記のように精製された1価金錯体を水に投入して、水酸化カリウムでpH5に調整して、金イオンを100g/L含む1価金錯体シロップを調製した。 The monovalent gold complex purified as described above was poured into water and adjusted to pH 5 with potassium hydroxide to prepare a monovalent gold complex syrup containing 100 g / L of gold ions.
参 考 例 2
   1価金錯体の調製:
 チオプロニン0.05Mおよび亜硫酸金ナトリウム0.05Mを含む水溶液を20℃で10時間攪拌し、1価金錯体を生成させた。この水溶液のpHを酢酸で3以下にすることにより、生成した1価金錯体は沈殿した。次に、水溶液を0.4μmのメンブレンフィルターでろ過することにより、1価金錯体を単離した。この操作における金の回収率は99.9%であった。
Reference example 2
Preparation of monovalent gold complex:
An aqueous solution containing 0.05 M thiopronin and 0.05 M sodium gold sulfite was stirred at 20 ° C. for 10 hours to form a monovalent gold complex. By adjusting the pH of this aqueous solution to 3 or less with acetic acid, the produced monovalent gold complex was precipitated. Next, the monovalent gold complex was isolated by filtering the aqueous solution through a 0.4 μm membrane filter. The gold recovery rate in this operation was 99.9%.
参 考 例 3
   電解金めっき液の調製:
 参考例1で調製した1価金錯体シロップ50ml/L(金イオンとして5g/L)、クエン酸三カリウム一水和物65g/Lを含有する水溶液を調製し、この水溶液のpHを水酸化カリウムで7.2に調整したものを電解金めっき液とした。
Reference example 3
Preparation of electrolytic gold plating solution:
An aqueous solution containing 50 ml / L of monovalent gold complex syrup prepared in Reference Example 1 (5 g / L as gold ion) and 65 g / L of tripotassium citrate monohydrate was prepared, and the pH of this aqueous solution was adjusted to potassium hydroxide. The solution adjusted to 7.2 was used as an electrolytic gold plating solution.
参 考 例 4
   電解金めっき:
 銅試験片に、電解脱脂、ソフトエッチング、酸処理等の一般的に公知な前処理を行ってから、電解ニッケルめっきを行った。その直後に参考例3で調製した電解金めっき液を用いて、銅上ニッケルめっきされた試験片に金めっきを行った。試験片のめっきされる部分のサイズは2cm×2cmで、陽極の面積はめっき面積の1.5~2.0倍であった。陽極は酸化イリジウムをコーティング層としたチタンの不溶性アノードであり、試験片(陰極として)との距離は約6cmであった。容量100mlの耐熱塩化ビニール製のめっき槽に、液温60℃を維持し、電流密度0.4A/dmで、撹拌しながら、2分間電解金めっきを行った。
Reference example 4
Electrolytic gold plating:
The copper test piece was subjected to generally known pretreatment such as electrolytic degreasing, soft etching, and acid treatment, and then electrolytic nickel plating was performed. Immediately thereafter, the electrolytic gold plating solution prepared in Reference Example 3 was used to perform gold plating on a test piece plated with nickel on copper. The size of the plated portion of the test piece was 2 cm × 2 cm, and the area of the anode was 1.5 to 2.0 times the plating area. The anode was an insoluble titanium anode with iridium oxide as a coating layer, and the distance from the test piece (as a cathode) was about 6 cm. Electrolytic gold plating was performed for 2 minutes in a plating tank made of heat-resistant vinyl chloride having a capacity of 100 ml while maintaining a liquid temperature of 60 ° C. and stirring at a current density of 0.4 A / dm 2 .
 金めっき後の外観は金色であった。また、金めっきをSEM観察したところ、規則形状を有する平滑の表面であった。しかし、電解金めっきにおける陰極電流効率(以下電流効率と言う)を「実際の析出量/理論の析出量×100%」から算出したところ30%であった。また、長時間めっきを行った場合、外観は赤くなりやすく、めっき液のpHは段々下っていくことがわかった。 The appearance after gold plating was gold. Further, when the gold plating was observed by SEM, it was a smooth surface having a regular shape. However, the cathode current efficiency (hereinafter referred to as current efficiency) in electrolytic gold plating was calculated from “actual precipitation amount / theoretical precipitation amount × 100%” and was 30%. Moreover, when plating was performed for a long time, it turned out that an external appearance tends to become red and the pH of a plating solution falls gradually.
実 施 例 1
   電解金めっき:
 参考例1で調製した1価金錯体シロップ40ml/L(金イオンとして4g/L)、硫酸カリウム44g/L、ギ酸タリウム24.4ppm(タリウムイオンとして20ppm)を含有する水溶液を調製し、この水溶液のpHを水酸化カリウムで6.2に調整したものを電解金めっき液とした。
Example 1
Electrolytic gold plating:
An aqueous solution containing 40 ml / L of monovalent gold complex syrup prepared in Reference Example 1 (4 g / L as gold ions), 44 g / L of potassium sulfate, and 24.4 ppm of thallium formate (20 ppm as thallium ions) was prepared. The solution was adjusted to 6.2 with potassium hydroxide as an electrolytic gold plating solution.
 この電解金めっき液について、参考例4と同様なめっき条件に電解金めっきを行ったところ、金めっき後の外観は金色であった。電解金めっきにおける電流効率を参考例4と同様に算出したところ90%以上であった。しかし、長時間めっきを行った場合、参考例4ほどではないが、外観は赤くなりやすく、めっき液のpHは段々下っていくことがわかった。 When this electrolytic gold plating solution was subjected to electrolytic gold plating under the same plating conditions as in Reference Example 4, the appearance after gold plating was gold. When the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 90% or more. However, when plating was performed for a long time, although not as much as in Reference Example 4, the appearance was likely to be red, and the pH of the plating solution gradually decreased.
試 験 例 1
   電気化学測定:
 実施例1で得られた電解金めっき液(タリウム20ppm添加)と、参考例3で調製した電解金めっき液(タリウム未添加)の電気化学測定で得た分極曲線を図1に示した。結晶調整剤として金属であるタリウムの添加により、分極曲線は右にシフトして、分極はかなりしやすくなることが分かった。そして、タリウムを添加した電解金めっき液の電流効率はタリウム未添加の電解金めっき液の約2倍となって、ほぼ100%となった。
Test example 1
Electrochemical measurement:
Polarization curves obtained by electrochemical measurements of the electrolytic gold plating solution obtained in Example 1 (added with 20 ppm thallium) and the electrolytic gold plating solution prepared in Reference Example 3 (without adding thallium) are shown in FIG. It has been found that the addition of thallium, a metal as a crystal modifier, shifts the polarization curve to the right, making polarization much easier. The current efficiency of the electrolytic gold plating solution to which thallium was added was about 100%, which was about twice that of the electrolytic gold plating solution to which thallium was not added.
実 施 例 2
   電解金めっき:
 参考例1で調製した1価金錯体シロップ50ml/L(金イオンとして5g/L)、ギ酸カリウム42g/L、ギ酸タリウム24.4ppm(タリウムイオンとして20ppm)、EDTA7.31g/Lを含有する水溶液を調製し、この水溶液のpHを水酸化カリウムで7.4に調整したものを電解金めっき液とした。
Example 2
Electrolytic gold plating:
An aqueous solution containing 50 ml / L of monovalent gold complex syrup prepared in Reference Example 1 (5 g / L as gold ions), 42 g / L of potassium formate, 24.4 ppm of thallium formate (20 ppm as thallium ions), and 7.31 g / L of EDTA. A solution prepared by adjusting the pH of this aqueous solution to 7.4 with potassium hydroxide was used as an electrolytic gold plating solution.
 この電解金めっき液について、参考例4と同様に電解金めっきを行ったところ、金めっき後の外観は参考例4および実施例1で得られたものよりも明るい金色であった。電解金めっきにおける電流効率を参考例4と同様に算出したところ90%以上であった。更に、長時間めっきしてもめっき液のpHは安定であった。しかし、金めっき皮膜をSEM観察したところ、参考例4ほどではないが、ナノホールが若干認められた(図2)。 The electrolytic gold plating solution was subjected to electrolytic gold plating in the same manner as in Reference Example 4. As a result, the appearance after gold plating was brighter than those obtained in Reference Example 4 and Example 1. When the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 90% or more. Furthermore, the pH of the plating solution was stable even after plating for a long time. However, when the gold plating film was observed with an SEM, nanoholes were slightly observed, although not as much as in Reference Example 4 (FIG. 2).
実 施 例 3
   電解金めっき:
 参考例1で調製した1価金錯体シロップ50ml/L(金イオンとして5g/L)、ギ酸カリウム42g/L、ギ酸タリウム24.4ppm(タリウムイオンとして20ppm)、EDTA7.31g/L、チオサリチル酸1.54g/Lを含有する水溶液を調製し、この水溶液のpHを水酸化カリウムで7.4に調整したものを電解金めっき液とした。
Example 3
Electrolytic gold plating:
Monovalent gold complex syrup 50 ml / L prepared as in Reference Example 1 (5 g / L as gold ion), potassium formate 42 g / L, thallium formate 24.4 ppm (20 ppm as thallium ion), EDTA 7.31 g / L, thiosalicylic acid 1 An aqueous solution containing 0.54 g / L was prepared, and the pH of this aqueous solution was adjusted to 7.4 with potassium hydroxide to obtain an electrolytic gold plating solution.
 この電解金めっき液について、参考例4と同様に電解金めっきを行ったところ、金めっき後の外観は参考例4および実施例2で得られたものより明るい金色であった。電解金めっきにおける電流効率を参考例4と同様に算出したところ95%以上であった。また、金めっき皮膜をSEM観察したところ、実施例2で得られた金めっき皮膜に見られたナノホールは認められなくなった(図3)。 The electrolytic gold plating solution was subjected to electrolytic gold plating in the same manner as in Reference Example 4. As a result, the appearance after gold plating was brighter than those obtained in Reference Example 4 and Example 2. When the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 95% or more. Further, when the gold plating film was observed by SEM, nanoholes observed in the gold plating film obtained in Example 2 were not recognized (FIG. 3).
 実施例1、2、3で得られた金めっき皮膜の純度を、金めっき皮膜を金剥離剤で溶かして、ICPの分析で確認したところ、何れも99.9%以上であった。そのため実施例1、2、3で得られた金めっき皮膜は純金であることがわかった。また、金皮膜の硬度を確認するところ、MVK-G3ビッカース硬度計(AKASHI製)を用いた荷重5gで金めっき皮膜の硬度を測定した。実施例1、2、3で得られた金めっき皮膜のビッカース硬度は何れも110HV以下であり、300℃で30分間のアニール処理後は60~70HVとなって、電子製品の純金めっき皮膜に要求される良好な性能を有することが示された。 The purity of the gold plating film obtained in Examples 1, 2, and 3 was confirmed by ICP analysis after dissolving the gold plating film with a gold release agent and found to be 99.9% or more. Therefore, it was found that the gold plating films obtained in Examples 1, 2, and 3 were pure gold. Further, when the hardness of the gold film was confirmed, the hardness of the gold plating film was measured with a load of 5 g using an MVK-G3 Vickers hardness tester (manufactured by AKASHI). The Vickers hardness of the gold plating films obtained in Examples 1, 2, and 3 is 110 HV or less, and is 60 to 70 HV after 30 minutes of annealing at 300 ° C., which is required for pure gold plating films of electronic products. It has been shown to have good performance.
実 施 例 4
   電解金めっき:
 参考例1で調製した1価金錯体シロップ40ml/L(金イオンとして4g/L)、硫酸カリウム44g/L、酒石酸アンチモンカリウム(アンチモンイオンとして10ppm)、EDTA7.31g/L、クエン酸三ナトリウム10g/L、チオサリチル酸0.77g/Lを含有する水溶液を調製し、この水溶液のpHを水酸化カリウムで6.2に調整したものを電解金めっき液とした。
Example 4
Electrolytic gold plating:
Monovalent gold complex syrup prepared in Reference Example 1 40 ml / L (4 g / L as gold ion), 44 g / L potassium sulfate, potassium antimony tartrate (10 ppm as antimony ion), 7.31 g / L EDTA, 10 g trisodium citrate / L, an aqueous solution containing 0.77 g / L of thiosalicylic acid, and the pH of this aqueous solution adjusted to 6.2 with potassium hydroxide was used as the electrolytic gold plating solution.
 この電解金めっき液について、参考例4と同様に電解金めっきを行ったところ、金めっき皮膜の外観は参考例4で得られたものよりも明るい金色であって、実施例3で得られた金めっき皮膜より光沢の外観であった。電解金めっきにおける電流効率を参考例4と同様に算出したところ95%以上であった。また、金めっき皮膜をSEM観察したところ、結晶は緻密で、平滑の表面であることがわかった(図4)。また、金の純度は若干下るものの、ビッカース硬度は上がって、170HVになり、300℃で30分間のアニール処理後も80~90HVであった。 When this electrolytic gold plating solution was subjected to electrolytic gold plating in the same manner as in Reference Example 4, the appearance of the gold plating film was brighter than that obtained in Reference Example 4 and was obtained in Example 3. The appearance was brighter than the gold plating film. When the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 95% or more. Further, when the gold plating film was observed by SEM, it was found that the crystals were dense and had a smooth surface (FIG. 4). Further, although the purity of gold was slightly lowered, the Vickers hardness was increased to 170 HV, and after annealing at 300 ° C. for 30 minutes, it was 80 to 90 HV.
実 施 例 5
   マイクロバンプの形成:
 実施例4で調製した電解金めっき液を用いて、半導体ウェハーのバンプめっきを行った。レジストによるパターン化されたウェハー上(めっき下地素材はスパッタリング金)に、電流密度0.4A/dm、液温60℃、40分間で金めっきを行った。めっき後レジストを剥離し、表面を観察したところ、図5に示すような微細な金バンプ(幅10μm、高さ約10μm)が形成されていた。金バンプは真っ直ぐ上に成長していたことから、この電解金めっき液は、レジストをアタックしないことがわかった。
Example 5
Micro bump formation:
Using the electrolytic gold plating solution prepared in Example 4, bump plating of the semiconductor wafer was performed. Gold plating was performed on a resist-patterned wafer (plating base material was sputtering gold) at a current density of 0.4 A / dm 2 and a liquid temperature of 60 ° C. for 40 minutes. When the resist was peeled off after plating and the surface was observed, fine gold bumps (width: 10 μm, height: about 10 μm) as shown in FIG. 5 were formed. Since the gold bumps grew straight up, it was found that this electrolytic gold plating solution did not attack the resist.
比 較 例 1
   電解金めっき:
 シアン金めっきの市販品として電解純金めっき液SKYGOLD S-10(JCU製)を用いて、液温60℃、電流密度0.3A/dmで、撹拌しながら、2分間(膜厚0.35μm)電解金めっきを行った。
Comparative Example 1
Electrolytic gold plating:
Using an electrolytic pure gold plating solution SKYGOLD S-10 (manufactured by JCU) as a commercial product of cyan gold plating, the liquid temperature is 60 ° C., and the current density is 0.3 A / dm 2 for 2 minutes (thickness 0.35 μm). ) Electrolytic gold plating was performed.
比 較 例 2
   電解金めっき:
 亜硫酸金ナトリウム(金イオンとして10g/L)、亜硫酸ナトリウム80g/L、硫酸タリウム(タリウムイオンとして20ppm)、エチレンジアミン10g/L、EDTA4g/L、リン酸水素2ナトリウム20g/L、3,5-ジニトロ安息香酸1g/Lを含有する水溶液を調製し、この水溶液のpHを水酸化カリウムで8.0に調整したものを電解金めっき液とした。この液を用いて、液温60℃、電流密度0.5A/dmで、撹拌しながら、70秒間(膜厚0.35μm)電解金めっきを行った。
Comparative Example 2
Electrolytic gold plating:
Sodium gold sulfite (10 g / L as gold ion), sodium sulfite 80 g / L, thallium sulfate (20 ppm as thallium ion), ethylenediamine 10 g / L, EDTA 4 g / L, disodium hydrogen phosphate 20 g / L, 3,5-dinitro An aqueous solution containing 1 g / L of benzoic acid was prepared, and the pH of this aqueous solution was adjusted to 8.0 with potassium hydroxide was used as an electrolytic gold plating solution. Using this liquid, electrolytic gold plating was performed for 70 seconds (film thickness 0.35 μm) while stirring at a liquid temperature of 60 ° C. and a current density of 0.5 A / dm 2 .
試 験 例 2
   物性測定:
(1)はんだボール接合シェア強度と破壊モード
 実施例3、4と比較例1、2の液で得た金めっき皮膜のはんだボール接合シェア強度と破壊モードを比較した(図6)。
 はんだボール接合性の評価はM705(Sn-3.0Ag-0.5Cu)の0.76mmφのソルダーボール(千住金属工業製)、フラックスは529D(ペースト状:千住金属工業製)、リフローはRF-430-M2(パルス製)を使用し、トップ温度が260℃、融点以上の保持時間約32秒ではんだ実装後、ボンドテスター4000HS(ARCTEK製)を使用して、シェア速度が40mm/sでシェアテストを行った。なお、評価された金めっきの膜厚は全部(Ni5.0μm/Au0.35μm)であった。
 破壊モードは、破壊面にはんだボールの残り面積比率で評価した。界面破壊がなく、はんだボールの残りが多い場合に接合性が強いと評価し、はんだボールの残りがなくなって、界面破壊されている場合に接合性が弱いと評価した。図6に示すように、サンプル数20個で、本発明の実施例3と実施例4のはんだ接合強度は比較例1と比較例2と同等であって、破壊モードは界面破壊がほぼなかった。一方、比較例1のシアン金めっき液と比較例2の亜硫酸金めっき液ははんだ残りが少ないケースがやや多くて、界面破壊のケースもあって、実施例3と実施例4のように優れていないことがあった。
Test example 2
Physical property measurement:
(1) Solder ball joint shear strength and fracture mode The solder ball joint shear strength and fracture mode of the gold plating films obtained with the solutions of Examples 3 and 4 and Comparative Examples 1 and 2 were compared (FIG. 6).
Solder ball bondability was evaluated by M705 (Sn-3.0Ag-0.5Cu) 0.76mmφ solder ball (manufactured by Senju Metal Industry), flux 529D (paste: Senju Metal Industry), and reflow RF- Use 430-M2 (manufactured by Pulse), solder at a top temperature of 260 ° C and a retention time of about 32 seconds above the melting point, and then use a bond tester 4000HS (manufactured by ARCTEK) to share at a shear rate of 40 mm / s. Tested. The film thickness of the gold plating evaluated was all (Ni 5.0 μm / Au 0.35 μm).
The fracture mode was evaluated by the ratio of the remaining area of the solder balls on the fracture surface. It was evaluated that the bondability was strong when there was no interfacial fracture and there were many remaining solder balls, and it was evaluated that the bondability was weak when there was no remaining solder balls and the interface was broken. As shown in FIG. 6, with 20 samples, the solder joint strengths of Example 3 and Example 4 of the present invention were equivalent to those of Comparative Example 1 and Comparative Example 2, and the fracture mode was almost free from interface fracture. . On the other hand, the cyan gold plating solution of Comparative Example 1 and the gold sulfite gold plating solution of Comparative Example 2 are slightly more likely to have a little solder residue, and there are cases of interface breakdown. There was nothing.
(2)ワイヤボンディング強度
 実施例3、4と比較例1、2の液で得た金めっき皮膜のワイヤボンディング強度を比較した。
 ワイヤボンディング強度の測定は、金ワイヤφ18μm(GMH製)を用い、ボンダーHW27U-HF(パナソニック製)でワイヤを打って実装して、プルテスターBT-14(DAGE製)を用いてプル強度を測定した(プル強度測定における破壊モード(A~Eの5段階)を図7に示した。AとEは不合格)。なお、評価された金めっきの膜厚は全部(Ni5.0μm/Au0.35μm)であった。実施例3、4と比較例1、2の測定結果は全部B(合格)となった。ワイヤボンディング強度として、図8に示すように本発明の実施例3と実施例4の金めっき液は、比較例1のシアン金めっき液と比較例2の亜硫酸金めっき液と比べて、有意差なく、同じく優れていた。
(2) Wire bonding strength The wire bonding strengths of the gold plating films obtained with the solutions of Examples 3 and 4 and Comparative Examples 1 and 2 were compared.
Wire bonding strength is measured by using a gold wire φ18μm (manufactured by GMH), hitting and mounting the wire with bonder HW27U-HF (manufactured by Panasonic), and measuring pull strength using pull tester BT-14 (manufactured by DAGE). (Fracture modes (5 levels A to E) in the pull strength measurement are shown in FIG. 7. A and E fail). The film thickness of the gold plating evaluated was all (Ni 5.0 μm / Au 0.35 μm). The measurement results of Examples 3 and 4 and Comparative Examples 1 and 2 were all B (pass). As for wire bonding strength, as shown in FIG. 8, the gold plating solutions of Example 3 and Example 4 of the present invention are significantly different from the cyan gold plating solution of Comparative Example 1 and the gold sulfite gold plating solution of Comparative Example 2. Not as good.
 以上の測定結果から、実施例3、4の金めっき液で得られる金めっき皮膜は、従来使用されていた比較例1のシアン浴と比較例2の亜硫酸浴で得られる金めっき皮膜と同程度かそれ以上で電気部品に要求される特性を有している。そのため、本発明はシアン系化合物を含む電解金めっき液に代えて使用できることがわかった。 From the above measurement results, the gold plating film obtained with the gold plating solutions of Examples 3 and 4 is almost the same as the gold plating film obtained with the cyan bath of Comparative Example 1 and the sulfite bath of Comparative Example 2 that have been used conventionally. It has the characteristics required for electrical components at or above. Therefore, it was found that the present invention can be used in place of an electrolytic gold plating solution containing a cyanide compound.
実 施 例 6
   電解金めっき:
 参考例1で調製した1価金錯体シロップ50ml/L(金イオンとして5g/L)、ギ酸カリウム42g/L、メタンスルホン酸ビスマス(ビスマスとして20ppm)、EDTA7.31g/L、チオグリコール酸0.46g/Lを含有する水溶液を調製し、この水溶液のpHを水酸化カリウムで7.4に調整したものを電解金めっき液とした。
Example 6
Electrolytic gold plating:
50 ml / L of monovalent gold complex syrup prepared in Reference Example 1 (5 g / L as gold ion), 42 g / L of potassium formate, bismuth methanesulfonate (20 ppm as bismuth), 7.31 g / L of EDTA, and 0.1 mg of thioglycolic acid. An aqueous solution containing 46 g / L was prepared, and the pH of this aqueous solution was adjusted to 7.4 with potassium hydroxide was used as an electrolytic gold plating solution.
 この電解金めっき液について、参考例4と同様に電解金めっきを行ったところ、金めっき後の外観は参考例4より明るい金色であった。電解金めっきにおける電流効率を参考例4と同様に算出したところ90%以上であった。 When this electrolytic gold plating solution was subjected to electrolytic gold plating in the same manner as in Reference Example 4, the appearance after gold plating was brighter than Reference Example 4. When the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 90% or more.
実 施 例 7
   電解金めっき:
 参考例1で調製した1価金錯体シロップ50ml/L(金イオンとして5g/L)、ギ酸カリウム42g/L、硫酸スズ(スズとして100ppm)、EDTA5.8g/Lを含有する水溶液を調製し、この水溶液のpHを水酸化カリウムで7.4に調整したものを電解金めっき液とした。
Example 7
Electrolytic gold plating:
An aqueous solution containing 50 ml / L of monovalent gold complex syrup prepared in Reference Example 1 (5 g / L as gold ions), 42 g / L of potassium formate, tin sulfate (100 ppm as tin), 5.8 g / L of EDTA, A solution prepared by adjusting the pH of this aqueous solution to 7.4 with potassium hydroxide was used as an electrolytic gold plating solution.
 この電解金めっき液に、銅上ニッケルめっきされた試験片を入れ、液温60℃、電流密度1A/dmで軽く撹拌して、3分間電解金めっきを行った。めっき後の外観は光沢の明るい金色となった。SEMで観察したところ、表面形態は結構平滑であり、実施例3、4と比べて、結晶粒子の界面が全然見えない状態であった(図9)。電解金めっきにおける電流効率を参考例4と同様に算出したところ40%となった。皮膜の金の純度を確認したところ、組成は金99.4%、スズ0.6%の金合金となっていた。 A test piece plated with nickel on copper was put into this electrolytic gold plating solution, and the mixture was lightly stirred at a liquid temperature of 60 ° C. and a current density of 1 A / dm 2 to perform electrolytic gold plating for 3 minutes. The appearance after plating was bright and bright gold. When observed by SEM, the surface morphology was fairly smooth, and the interface of crystal grains was not visible at all compared to Examples 3 and 4 (FIG. 9). When the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 40%. When the gold purity of the film was confirmed, the composition was a gold alloy of 99.4% gold and 0.6% tin.
実 施 例 8
   電解金めっき:
 参考例1で調製した1価金錯体シロップ80ml/L(金イオンとして8g/L)、硫酸カリウム44g/L、硫酸スズ(スズとして100ppm)、EDTA7.31g/L、チオサリチル酸1.54g/Lを含有する水溶液を調製し、この水溶液のpHを水酸化カリウムで7.4に調整したものを電解金めっき液とした。
Example 8
Electrolytic gold plating:
Monovalent gold complex syrup prepared in Reference Example 1 80 ml / L (8 g / L as gold ion), potassium sulfate 44 g / L, tin sulfate (100 ppm as tin), EDTA 7.31 g / L, thiosalicylic acid 1.54 g / L An aqueous solution containing the solution was prepared, and the pH of this aqueous solution was adjusted to 7.4 with potassium hydroxide was used as the electrolytic gold plating solution.
 この電解金めっき液について、参考例4と同様に電解金めっきを行ったところ、金めっき後の外観は参考例4および実施例1で得られたものよりも明るい金色であった。電解金めっきにおける電流効率を参考例4と同様に算出したところ90%であった。皮膜の金の純度を確認したところ、組成は金99.2%、スズ0.8%の金合金となっていた。 The electrolytic gold plating solution was subjected to electrolytic gold plating in the same manner as in Reference Example 4. As a result, the appearance after gold plating was brighter than those obtained in Reference Example 4 and Example 1. When the current efficiency in electrolytic gold plating was calculated in the same manner as in Reference Example 4, it was 90%. When the gold purity of the film was confirmed, the composition was a gold alloy of 99.2% gold and 0.8% tin.
実 施 例 9
   電解金めっき液の調製:
 2,4‐チアゾリジンジオンの加水分解から生成した2-メルカプトアセトアミド0.15Mおよび塩化金酸0.05Mを含む水溶液を20℃で10時間攪拌し、1価金錯体を生成させた。なお、この水溶液のpHは3以下であるため、生成した1価金錯体は溶解せず沈殿物となっている。次に、この水溶液を0.4μmのメンブレンフィルターでろ過することにより、1価金錯体を単離した。この操作における金の回収率は99.9%であった。なお、この1価金錯体の構造は式(IV)のような構造(nは1~10)であることをNMRで確認した。この1価金錯体は上記実施例と同様に電解金めっき液に使用し得る。
Example 9
Preparation of electrolytic gold plating solution:
An aqueous solution containing 0.15M 2-mercaptoacetamide and 0.05M chloroauric acid generated from the hydrolysis of 2,4-thiazolidinedione was stirred at 20 ° C. for 10 hours to form a monovalent gold complex. In addition, since the pH of this aqueous solution is 3 or less, the produced | generated monovalent | monohydric complex does not melt | dissolve but becomes a precipitate. Next, this aqueous solution was filtered with a 0.4 μm membrane filter to isolate a monovalent gold complex. The gold recovery rate in this operation was 99.9%. The structure of the monovalent gold complex was confirmed by NMR to be a structure represented by the formula (IV) (n is 1 to 10). This monovalent gold complex can be used in an electrolytic gold plating solution as in the above examples.
Figure JPOXMLDOC01-appb-C000006
 
Figure JPOXMLDOC01-appb-C000006
 
実 施 例 10
   電解金めっき:
 ロダニン-3-酢酸の加水分解から生成したN-(2-メルカプトエチオニル)グリシン0.15Mおよび塩化金酸0.05Mを含む水溶液を20℃で10時間攪拌し、1価金錯体を生成させた。なお、この水溶液のpHは3以下であるため、生成した1価金錯体は溶解せず沈殿物となっている。次に、この水溶液を0.4μmのメンブレンフィルターでろ過することにより、1価金錯体を単離した。この操作における金の回収率は99.9%であった。なお、この1価金錯体の構造は式(V)のような構造(nは1~10)であることをNMRで確認した。
Example 10
Electrolytic gold plating:
An aqueous solution containing 0.15 M N- (2-mercaptoethionyl) glycine and 0.05 M chloroauric acid generated by hydrolysis of rhodanine-3-acetic acid was stirred at 20 ° C. for 10 hours to form a monovalent gold complex. It was. In addition, since the pH of this aqueous solution is 3 or less, the produced | generated monovalent | monohydric complex does not melt | dissolve but becomes a precipitate. Next, this aqueous solution was filtered with a 0.4 μm membrane filter to isolate a monovalent gold complex. The gold recovery rate in this operation was 99.9%. The structure of the monovalent gold complex was confirmed by NMR to be a structure represented by the formula (V) (n is 1 to 10).
Figure JPOXMLDOC01-appb-C000007
 
Figure JPOXMLDOC01-appb-C000007
 
 上記式(V)の1価金錯体を参考例1と同様にしてシロップとし、これを実施例1で用いた1価金錯体シロップに代えて電解金めっき液を調製した。この電解金めっき液で、電解金めっきを行うと、同様の金めっき皮膜を得る。 The monovalent gold complex of the above formula (V) was made into a syrup in the same manner as in Reference Example 1, and this was replaced with the monovalent gold complex syrup used in Example 1 to prepare an electrolytic gold plating solution. When electrolytic gold plating is performed with this electrolytic gold plating solution, a similar gold plating film is obtained.
実 施 例 11
   電解金めっき液の調製::
 2,4‐チアゾリジンジオン及び2-アミノエタノールの加水分解から生成したN-(2-ヒドロキシエチル)-2-メルカプトアセトアミド0.15Mおよび塩化金酸0.05Mを含む水溶液を20℃で10時間攪拌し、1価金錯体を生成させた。なお、この水溶液のpHは3以下であるため、生成した1価金錯体は溶解せず沈殿物となっている。次に、この水溶液を0.4μmのメンブレンフィルターでろ過することにより、1価金錯体を単離した。この操作における金の回収率は99.9%であった。なお、この1価金錯体の構造は式(VI)のような構造(nは1~10)であることをNMRで確認した。この1価金錯体は上記実施例と同様に電解金めっき液に使用し得る。
Example 11
Preparation of electrolytic gold plating solution ::
An aqueous solution containing 0.15M N- (2-hydroxyethyl) -2-mercaptoacetamide and 0.05M chloroauric acid formed from the hydrolysis of 2,4-thiazolidinedione and 2-aminoethanol was stirred at 20 ° C. for 10 hours. And a monovalent gold complex was produced. In addition, since the pH of this aqueous solution is 3 or less, the produced | generated monovalent | monohydric complex does not melt | dissolve but becomes a precipitate. Next, this aqueous solution was filtered with a 0.4 μm membrane filter to isolate a monovalent gold complex. The gold recovery rate in this operation was 99.9%. The structure of the monovalent gold complex was confirmed by NMR to be a structure represented by the formula (VI) (n is 1 to 10). This monovalent gold complex can be used in an electrolytic gold plating solution as in the above examples.
Figure JPOXMLDOC01-appb-C000008
 
Figure JPOXMLDOC01-appb-C000008
 
 本発明のノーシアン電解金めっき液は、実用的なものであり、これまで使用されていたシアン系化合物を含む電解金めっき液に代えて使用することができる。
 
                          以  上
The non-cyanide electrolytic gold plating solution of the present invention is practical and can be used in place of the electrolytic gold plating solution containing a cyanide compound that has been used so far.

more than

Claims (11)

  1.  以下の成分(a)~(c)
    (a)下記一般式(I)で示される1価金錯体
    Figure JPOXMLDOC01-appb-C000001
     
    (ただし、式(I)中、Rは、水素またはメルカプト基を有していてもよく分岐していてもよい炭素数1~4のアルキル基を示し、Rは、水素または分岐していてもよい炭素数1~4のアルキル基を示し、Rは、水素、分岐していてもよい炭素数1~4のアルキル基、ヒドロキシアルキル基、またはメルカプト基を有していてもよく分岐していてもよい炭素数1~4のカルボキシアルキル基を示し、nは1~10の整数を示す。)
    (b)電解質
    (c)金属から選ばれる結晶調整剤
    を含有することを特徴とするノーシアン電解金めっき液。
    The following components (a) to (c)
    (A) Monovalent gold complex represented by the following general formula (I)
    Figure JPOXMLDOC01-appb-C000001

    (In the formula (I), R 1 represents hydrogen or a mercapto group which may be branched or optionally branched alkyl group 1 to 4; R 2 is hydrogen or branched. R 3 represents an optionally substituted alkyl group having 1 to 4 carbon atoms, and R 3 may have hydrogen, an optionally branched alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, or a mercapto group. And optionally represents a carboxyalkyl group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10.)
    (B) Electrolyte (c) A cyanide electrolytic gold plating solution containing a crystal modifier selected from metals.
  2.  成分(a)の一般式(I)で示される1価金錯体が、式(I)中のRが水素、Rがメチル基、Rがカルボキシメチル基を示し、nは4のものである請求項1記載のノーシアン電解金めっき液。 The monovalent gold complex represented by the general formula (I) of the component (a) is one in which R 1 in the formula (I) is hydrogen, R 2 is a methyl group, R 3 is a carboxymethyl group, and n is 4. The nocyan electrolytic gold plating solution according to claim 1.
  3.  成分(b)の電解質が、無機酸または有機酸のカリウム塩、ナトリウム塩、アンモニウム塩からなる群から選ばれる1種または2種以上である請求項1記載のノーシアン電解金めっき液。 The non-cyanide electrolytic gold plating solution according to claim 1, wherein the electrolyte of component (b) is one or more selected from the group consisting of potassium salts, sodium salts, and ammonium salts of inorganic or organic acids.
  4.  成分(c)の金属から選ばれる結晶調整剤の金属が、タリウム、アンチモン、ヒ素、ビスマス、スズ、鉛、インジウム、ゲルマニウム、ガリウム、テルル、セリウム、セレン、コバルトおよびニッケルからなる群から選ばれる1種または2種以上である請求項1記載のノーシアン電解金めっき液。 The metal of the crystal modifier selected from the metals of component (c) is selected from the group consisting of thallium, antimony, arsenic, bismuth, tin, lead, indium, germanium, gallium, tellurium, cerium, selenium, cobalt and nickel The norcyan electrolytic gold plating solution according to claim 1, which is a seed or two or more.
  5.  更に、成分(d)および(e)
    (d)pH緩衝剤
    (e)硫黄含有化合物から選ばれる結晶調整剤
    からなる群から選ばれる1種または2種を含有する請求項1~4の何れかに記載のノーシアン電解金めっき液。
    In addition, components (d) and (e)
    5. The non-cyanide gold plating solution according to claim 1, comprising (d) a pH buffer (e) one or two selected from the group consisting of crystal modifiers selected from sulfur-containing compounds.
  6.  成分(d)のpH緩衝剤が、無機酸、有機カルボン酸、有機リン酸、ピリジンスルホン酸およびこれらのカリウム塩、ナトリウム塩、アンモニウム塩からなる群から選ばれる1種または2種以上である請求項5記載のノーシアン電解金めっき液。 The pH buffer of component (d) is one or more selected from the group consisting of inorganic acids, organic carboxylic acids, organic phosphoric acids, pyridinesulfonic acids, and potassium, sodium and ammonium salts thereof. Item 6. A non-cyanide gold plating solution according to item 5.
  7.  成分(e)の硫黄含有化合物から選ばれる結晶調整剤の硫黄含有化合物が、チオ硫酸ならびにチオリン酸およびこれらのカリウム塩、ナトリウム塩、アンモニウム塩、メルカプト基とカルボキシ基の両方を有する有機化合物からなる群から選ばれる1種または2種以上である請求項5記載のノーシアン電解金めっき液。 The sulfur-containing compound of the crystal modifier selected from the sulfur-containing compounds of component (e) is composed of thiosulfuric acid and thiophosphoric acid and their potassium, sodium, ammonium, and organic compounds having both mercapto and carboxy groups. The nocyan electrolytic gold plating solution according to claim 5, which is one or more selected from the group.
  8.  pHが3~14である請求項1~7の何れかに記載のノーシアン電解金めっき液。 The non-cyanide gold plating solution according to any one of claims 1 to 7, wherein the pH is 3 to 14.
  9.  被めっき部材を、請求項1~8の何れかに記載のノーシアン電解金めっき液中で電解めっきすることを特徴とする被めっき部材のノーシアン電解金めっき方法。 9. A method for non-cyanide electrolytic gold plating of a member to be plated, comprising subjecting the member to be plated to electrolytic plating in the non-cyanide electrolytic gold plating solution according to any one of claims 1 to 8.
  10.  電解めっき中の液温が20~80℃、電流密度が0.1~6A/dmである請求項9記載の被めっき部材のノーシアン電解金めっき方法。 10. The method for non-cyanide electroplating of a member to be plated according to claim 9, wherein the temperature of the solution during electroplating is 20 to 80 ° C. and the current density is 0.1 to 6 A / dm 2 .
  11.  請求項9または10に記載の被めっき部材のノーシアン電解金めっき方法により得られる金めっき部材。
     
    A gold-plated member obtained by the nocyan electrolytic gold plating method for a member to be plated according to claim 9 or 10.
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