JP6063221B2 - Gold concentration determination method and gold concentration determination apparatus in plating solution - Google Patents

Description

  The present invention relates to a gold concentration quantification method and a gold concentration quantification apparatus in a gold-containing solution. Specifically, the present invention relates to a technique for efficiently quantifying the gold concentration in a gold-containing solution represented by a plating solution or the like with higher sensitivity and in a shorter time. Below, although it demonstrates centering on a plating solution, the technique of this invention is not the meaning limited to this.

  Gold plating technology for plating a coating with gold excellent in spreadability, corrosion resistance, conductivity, etc. is widely used for reasons such as being suitable for mass production. In general, the method of reducing the metal ions in the plating solution and plating (depositing the metal on the coating) is roughly divided into an electroplating method using an external current and an electroless plating method that does not act on electricity. . The latter electroless plating method further includes a displacement plating method (also referred to as an immersion plating method) in which a metal to be plated is immersed in a solution, and a reduction plating method using a chemical reduction reaction (also referred to as a chemical plating method). It is roughly divided into.

  A plating solution used for gold plating is continuously and repeatedly used. Specifically, the coating is plated over a long period of time until plating performance is significantly degraded due to accumulation of by-products and impurities. Therefore, the plating solution (aging solution) after repeated use has a significantly reduced gold concentration in the plating solution and is less likely to deposit (precipitate) compared to the plating solution (new solution) before starting plating or immediately after starting plating. Or a problem that a high-quality gold plating film cannot be obtained. Such a problem is noticeable when a plating solution containing a large number of additives in the plating solution is used, for example, as in an electroless plating method. In addition to solutions containing gold ions, electroless plating solutions contain many additives such as reducing agents, pH buffering agents, complexing agents and stabilizers for reducing gold ions, so the plating solution can be used repeatedly. As a result, byproducts and impurities are easily accumulated, and the plating solution deteriorates. Therefore, the decrease in gold ion concentration in the plating solution can be detected quickly and accurately so that a high-quality gold plating film can be obtained even when the plating solution is used repeatedly. In the case where the amount is insufficient, it is desired to provide a technique capable of quickly replenishing the plating solution with the insufficient gold-containing component.

  Conventionally, the gold concentration in the plating solution is mainly measured by an analytical method such as an atomic absorption method or an ICP method [an emission spectroscopic analysis method using high frequency inductively coupled plasma (ICP) as a light source]. Specifically, the above analyzer is attached outside the line of the plating apparatus, the plating solution is manually sampled from the plating tank in the plating apparatus, and supplied to the analyzer to analyze the gold concentration. However, since the analysis method requires a lot of time, there is a time lag after the plating solution is sampled until the gold concentration measurement result is obtained. Therefore, when the plating solution deteriorates due to insufficient gold ions during plating, appropriate measures such as immediately replenishing the necessary gold-containing components or replacing the plating solution with a new one depending on the deterioration state of the plating solution Cannot be performed quickly, and a high-quality plating film cannot be obtained.

  Therefore, in Patent Document 1, an absorbance near a wavelength of 340 to 450 nm, which is peculiar to a gold plating solution, is measured by an absorptiometric analyzer instead of an analyzer such as an atomic absorption method, and the deterioration of the gold plating solution depends on the magnitude of the absorbance. A technique for detecting the degree is disclosed. Since the absorbance in the above-mentioned wavelength region is particularly reduced every time the number of plating treatments is increased, the method of Patent Document 1 can detect the degree of deterioration of the gold plating solution in a short time, and the gold plating solution can be efficiently and in an appropriate state. It can be exchanged with. Specifically, a gold thin film (plating film) is formed on the target object by detecting the absorbance of the gold plating solution that has become defective in advance and replacing the gold plating solution that has decreased to this absorbance. It is stated that it can be done.

  However, since the absorbance measurement wavelength region (around 340 to 450 nm wavelength) described in Patent Document 1 overlaps with the absorbance of impurities and the like contained in the plating solution, the method of Patent Document 1 accurately determines the gold concentration in the plating solution. There is a problem that cannot be measured.

  In the above description, the plating has been described as an example. However, such a problem (a problem that it is difficult to quickly and accurately measure the gold concentration in the plating solution) is not limited to the plating. The case where other gold-containing solutions are used is also proposed.

JP-A-2-110348

  The present invention has been made in view of the above circumstances, and its purpose is to increase the gold concentration in a gold-containing solution represented by a plating solution, regardless of the degree of deterioration due to repeated use of the gold-containing solution. The object is to provide a technique capable of quantifying efficiently in a short time with high sensitivity.

  The method of the present invention capable of achieving the above object is a method for quantifying the gold concentration in a gold-containing solution, the first step of mixing the gold-containing solution, the reducing agent, the iodide, and water, And a second step of measuring the gold concentration in the mixed solution by an absorbance method in a predetermined wavelength region.

  In a preferred embodiment of the present invention, the mixed solution contains gold colloid.

  In a preferred embodiment of the present invention, the predetermined wavelength range is 520 nm ± 10 nm.

  In a preferred embodiment of the present invention, the concentration of the reducing agent contained in the mixed solution is 0.01 to 0.2 g / L, and the concentration of iodide contained in the mixed solution is 0.5 to 5.0 g / L. L.

  In a preferred embodiment of the present invention, the gold-containing solution is a plating solution.

  The apparatus of the present invention that has achieved the above-described object is a gold concentration quantification apparatus that quantifies the gold concentration in a gold-containing solution, and adds and mixes the gold-containing solution, the reducing agent, the iodide, and water. And a spectrophotometer for measuring the absorbance in a predetermined wavelength region of the mixed solution prepared in the reaction vessel.

  In a preferred embodiment of the present invention, the apparatus further includes a gold concentration display device that displays a gold concentration in the mixed solution or the gold-containing solution based on the absorbance.

  In a preferred embodiment of the present invention, the apparatus further includes a replenishment amount adjusting device that replenishes a gold-containing component in the gold-containing solution to adjust a gold concentration in the gold-containing solution according to the absorbance.

  In a preferred embodiment of the present invention, the predetermined wavelength range is 520 nm ± 10 nm.

  According to the method of the present invention, when measuring the gold concentration in a gold-containing solution by the absorbance method, a mixed solution in which a reducing agent, iodide, and water are added to the gold-containing solution is prepared, and the gold-containing solution is repeatedly used. Measures the absorbance in a specified wavelength range that is not easily affected by deterioration (increased impurities and by-products, etc.), so that the gold concentration in the gold-containing solution is highly accurate, sensitive, and efficient in a short time. Can be quantitatively determined. In addition, the gold concentration in the gold-containing solution can be easily converted by introducing the measurement result of the absorbance in the predetermined wavelength range into a known relational expression (relational expression between absorbance and gold concentration) acquired in advance. Can be obtained.

  If the method of the present invention reveals that the gold concentration in the gold-containing solution has been reduced to below the allowable range, the gold-containing solution corresponding to the gold concentration reduction amount may be replenished to the gold-containing solution. Thus, for example, the gold concentration during the plating process (during the production of the plating film) can be kept constant at all times. As a result, there is no variation in the quality of the processed product (for example, plating film), and a high-quality product can always be supplied stably. In addition, since the deterioration degree of the gold-containing solution can be managed over time by integrating the replenishment amount of the gold-containing component, it is possible to accurately grasp the replacement time of the gold-containing solution.

  Further, according to the apparatus of the present invention, since the apparatus includes at least a reaction vessel for preparing the mixed solution and an absorptiometer for measuring the absorbance of the mixed solution, the gold concentration analysis is performed. Can be carried out easily and frequently, and the accuracy of gold concentration determination is further improved. Preferably, in the apparatus of the present invention, a gold concentration display device that displays the gold concentration in the mixed solution or the gold-containing solution based on the absorbance described above, or a replenishment amount adjusting device is provided. Plating treatment, etc.) and gold concentration analysis in the gold-containing solution treatment tank can be performed simultaneously on the production line. As a result, conventional problems such as time lag between processing and measurement are also solved. Furthermore, there is also a merit that the change with time of the gold concentration in the gold-containing solution treatment tank can be accurately recorded in the production history.

FIG. 1 is a diagram showing a configuration of a gold concentration quantification apparatus according to the present invention. FIG. 2 is a graph showing the results of absorption spectra in the range of 400 to 800 nm when various halides are used as reducing aids in Example 1 with different addition amounts (leaving time 30 minutes). . 2A is a 0.05 MI ₂ solution, FIG. 2B is a 5% KI solution, FIG. 2C is a 5% KBr solution, FIG. 2D is a 5% KCl solution, and FIG. Shows the results of 5% NaCl solution, and FIG. 2 (f) shows the results of 5% KF solution. FIG. 3 is a diagram showing the results of absorption spectra when various halides (addition amount of 1 mL) are used as the reduction assistant in Example 1 and the standing time is changed. 3 (a) is a 0.05 MI ₂ solution, FIG. 3 (b) is a 5% KI solution, FIG. 3 (c) is a 5% KBr solution, FIG. 3 (d) is a 5% KCl solution, and FIG. 3 (e). Shows the results for a 5% NaCl solution, and FIG. 3 (f) shows the results for a 5% KF solution. FIG. 4 is a graph showing the results of an absorption spectrum when a KI solution is used as a reducing aid in Example 1 and the amount of KI solution added is changed. 4A shows the results of 0.5 mL, FIG. 4B shows the results of 1 mL, FIG. 4C shows the results of 2 mL, FIG. 4D shows the results of 3 mL, and FIG. FIG. 5 is a diagram showing the results of examining the preferred addition amounts of reducing agent and reducing aid when a new solution is used as the plating solution in Example 2. (A), (b), (c), and (d) in FIG. 5 show the results when 1 mL, 2 mL, 3 mL, and 4 mL of the KI solution were added, respectively. FIG. 6 is a diagram showing the results of examining the preferred addition amounts of the reducing agent and the reducing aid when an aging solution is used as the plating solution in Example 2. (A), (b), (c), and (d) of FIG. 6 show the results when 1 mL, 2 mL, 3 mL, and 4 mL of the KI solution were added, respectively. FIG. 7A is a diagram showing the results of examining the effects of mixing temperature and standing time when preparing a mixed solution in Example 3. FIG. 7A shows the result when the mixing temperature is 15 ° C. and the standing time is 10 to 60 minutes; FIG. 7B shows the result when the mixing temperature is 20 ° C. and the standing time is 5 to 40 minutes. FIG. 7 (c) shows the results when the mixing temperature is 25 ° C. and the standing time is 5 to 40 minutes; FIG. 7 (d) shows the results when the mixing temperature is 30 ° C. and the standing time is 5 to 40 minutes. FIG. 7 (e) shows the result when the mixing temperature is 35 ° C. and the standing time is 5 to 40 minutes; FIG. 7 (f) shows the mixing temperature is 40 ° C. and the standing time is 5 to 40 minutes. The results are shown respectively. FIG. 7B is a diagram showing the results of examining the effects of mixing temperature and standing time when preparing a mixed solution in Example 3. FIG. 7 (g) shows the results when the mixing temperature is 45 ° C. and the standing time is 5 to 40 minutes. FIG. 8 is a diagram showing the results of examining the effects of mixing temperature and standing time when preparing a mixed solution in Example 4. FIG. 8A shows the result of the standing time of 20 minutes, and FIG. 8B shows the result of the standing time of 30 minutes. FIG. 9 shows the results of the absorption spectrum in the range of 400 to 800 nm when the new solution was used as the plating solution in Example 5 and the addition amount of the reducing agent and the reducing aid was changed (leaving time 20 minutes). FIG. (A), (b), and (c) of FIG. 9 show the results when 3 mL, 5 mL, and 7 mL of the KI solution were added, respectively. FIG. 10 shows the results of absorption spectra in the range of 400 to 800 nm when the aging solution is used as the plating solution in Example 5 and the addition amount of the reducing agent and the reducing aid is changed (the standing time is 20 minutes). FIG. (A), (b), (c), and (d) of FIG. 10 show the results when 3 mL, 5 mL, 7 mL, and 10 mL of the KI solution were added, respectively. FIG. 11 shows the results of an absorption spectrum in the range of 400 to 800 nm when a new solution is used as the plating solution in Example 6 and the addition amount of the reducing agent and the reducing aid is changed (the standing time is 30 minutes). FIG. (A), (b), and (c) in FIG. 11 show the results when 3 mL, 5 mL, and 7 mL of the KI solution were added, respectively. FIG. 12 shows the results of the absorption spectrum in the range of 400 to 800 nm when the aging solution is used as the plating solution in Example 6 and the addition amount of the reducing agent and the reducing aid is changed (the standing time is 30 minutes). FIG. (A), (b), (c), and (d) in FIG. 12 show the results when 3 mL, 5 mL, 7 mL, and 10 mL of the KI solution were added, respectively. FIG. 13 is a diagram showing the results of absorption spectra in the range of 400 to 800 nm when the amount of addition of the reducing aid and the standing time are changed in Example 7 (1 mL of reducing agent, new solution as plating solution) use). (A), (b), (c), and (d) of FIG. 13 show the results when 3 mL, 4 mL, 5 mL, and 7 mL of the KI solution were added, respectively. FIG. 14 is a diagram showing the results of absorption spectra in the range of 400 to 800 nm when the amount of addition of the reduction aid and the standing time are changed in Example 7 (1.5 mL of reducing agent, as plating solution) Use new solution). (A), (b), (c), and (d) in FIG. 14 show the results when 3 mL, 4 mL, 5 mL, and 7 mL of the KI solution were added, respectively. FIG. 15 is a diagram showing the results of absorption spectra in the range of 400 to 800 nm when the amount of addition of the reducing aid and the standing time are changed in Example 8 (1 mL of reducing agent, aging solution as plating solution) use). (A), (b), (c), (d), and (e) in FIG. 15 show the results when the KI solution was added in 3 mL, 4 mL, 5 mL, 7 mL, and 10 mL, respectively. FIG. 16 is a diagram showing the results of absorption spectra in the range of 400 to 800 nm when the addition amount of the reducing aid and the standing time were changed in Example 8 (1.5 mL of reducing agent, as plating solution) Use aging solution). (A), (b), (c), (d), and (e) in FIG. 16 show the results when the KI solution was added in 3 mL, 4 mL, 5 mL, 7 mL, and 10 mL, respectively. FIG. 17A is a diagram showing the results of examining the effects of mixing temperature and standing time when preparing a mixed solution. FIG. 17A shows the result when the mixing temperature is 15 ° C. and the standing time is 10 to 60 minutes; FIG. 17B shows the result when the mixing temperature is 20 ° C. and the standing time is 10 to 50 minutes. FIG. 17 (c) and FIG. 17 (d) show the results when the mixing temperature is 25 ° C. and the standing time is 10 to 50 minutes; FIG. 17 (e) shows the mixing temperature is 30 ° C. and the standing time is 10 to 10 minutes; FIG. 17 (f) shows the results when the mixing temperature is 35 ° C. and the standing time is 5 to 40 minutes, respectively. FIG. 17B is a diagram showing the results of examining the effects of mixing temperature and standing time when preparing a mixed solution. FIG. 17 (g) shows the results when the mixing temperature is 40 ° C. and the standing time is 10 to 40 minutes. FIG. 18 is a diagram showing the results of examining the influence of the mixing temperature and the standing time when preparing the mixed solution. FIG. 18A shows the result of the standing time of 20 minutes, and FIG. 18B shows the result of the standing time of 30 minutes.

  The present invention is an improved technique of Patent Document 1 described above. As described above, the method of Patent Document 1 is susceptible to the effects of impurities and by-products generated with repeated use of the plating solution, and has a problem that the gold concentration cannot be measured accurately. Yes. Moreover, the said method does not consider the influence of the additive etc. which are contained in a plating solution at all. Therefore, the present inventors can solve the above problems, that is, the gold-containing solution regardless of the deterioration state of the gold-containing solution (increase in impurities and by-products described above) and the type and composition of the gold-containing solution. In order to provide a technique capable of quantifying gold concentration in a solution with higher accuracy and sensitivity, research has been repeated.

  As a result, as in the above-mentioned Patent Document 1, the gold-containing solution is the object to be measured, and the absorbance in the wavelength region (range of 340 to 450 nm) derived from gold in the gold-containing solution is not measured, but the viewpoint is changed. (A) a mixed solution obtained by adding a reducing agent, iodide, and water to a gold-containing solution, and (b) a predetermined wavelength region derived from the gold colloid in the mixed solution (the present invention) Then, it was found that the intended purpose was achieved by measuring the absorbance particularly in the wavelength range of 520 ± 10 nm, and the present invention was completed.

  Thus, as described in the above (a), one of the characteristic parts of the present invention is a mixture obtained by adding a reducing agent, iodide, and water to a gold-containing solution as a solution for gold concentration measurement by the absorbance method. The point is that the solution is used. In preparing the above mixed solution, in the present invention, since iodide is selected and used particularly as a reduction aid (reduction accelerator, color development aid), the influence of the deterioration state of the gold-containing solution (variation in absorbance measurement values) ) Is not seen. In this mixed solution, a gold colloid having a peak in the wavelength region described in the above (A) is generated. Therefore, the above (A) can be rephrased as a gold colloid generating means.

  The gold colloid is a colloid in which gold fine particles (nanoparticles) of 1 μm or less are dispersed in a solution. A gold colloid having a particle size of about 10 to 60 nm develops a purple color and has an absorption peak near 530 nm. Colloidal gold is usually produced by reducing gold ions with a reducing agent. However, since a gold-containing solution represented by a plating solution or the like contains many additives, colloidalization is very difficult. Further, even if the colloid is once generated, it becomes unstable due to an increase in the colloid particle size depending on the environmental conditions, and a decrease in absorbance (fading of colloidal gold) or the like is observed. Specifically, the electroless plating solution contains, in addition to the reducing agent, a reducing aid (also called a reduction accelerator, a color developing aid, etc.), and a complexing agent and stabilizer for stabilizing the plating solution. Contains many agents. Therefore, the reduced gold may be decomposed and deposited in the solution due to the type of reducing agent or excessive addition of the reducing agent. In addition, according to the experiments by the present inventors, depending on the type of the reducing aid, it is greatly affected by the deterioration of the solution due to repeated use, and there is a large difference in absorbance between the new solution and the aging solution. I understand.

  Therefore, the present inventors provide a colloidal gold generating means for always obtaining a constant colloidal gold (that is, stably obtaining a solution having an absorbance peak in the predetermined wavelength range) regardless of the degree of deterioration of the solution. We studied diligently. As a result, it became clear that the use of iodide as a reducing aid in addition to the reducing agent was indispensable, and the present invention has been achieved.

  Furthermore, another characteristic part of the present invention is to measure the absorbance in a predetermined wavelength range (specifically, a wavelength range of 520 ± 10 nm) when measuring the absorbance in the mixed solution as described in (a) above. There is a place to do. The vicinity of the maximum absorption wavelength of colloidal gold is 500 to 550 nm. In the present invention, the absorbance at 520 ± 10 nm was measured. The reason is that it has been found by many basic experiments that if the absorbance in the wavelength range is measured, it is difficult to be affected by the shift of the absorbance peak due to the degree of solution degradation at the time of gold colloid generation.

  The present invention will be described in detail below. In the present specification, the description will focus on the plating solution, but the gold-containing solution used in the present invention is not limited to the plating solution.

In this specification, for convenience, the term “new solution” or “aging solution” may be used. Among these, “new solution” means a new gold-containing solution before the start of use or immediately after the start of use. On the other hand, the “aging solution” means a gold-containing solution after repeated use. In general, since the aging degree of the electroless plating solution is indicated by MTO (Metal Turn Over), in the examples described later, the aging degree is expressed by MTO. The concentration of the metal components (Au, Ni, Cu, etc.) contained in the plating solution does not vary greatly because replenishment of consumables is performed at any time, but in order to integrate and manage the amount of replenished metal components, MTO It is represented by the following formula. 1MTO means a stage where all metal components in the plating solution are consumed. In the case of gold plating, although depending on the plating bath used, 3 to 4 MTO is said to be the limit for maintaining the plating treatment ability.
MTO = Total consumption of metal components / Amount of metal components during bathing (before plating)

  First, a method for quantifying the gold concentration in the gold-containing solution according to the present invention will be described. As described above, the gold concentration determination method of the present invention includes a first step of mixing a gold-containing solution, a reducing agent, iodide, and water, and measuring the gold concentration in the mixed solution by an absorbance method in a predetermined wavelength region. And a second step.

(First step)
In the first step, a gold-containing solution, a reducing agent, iodide, and water are mixed to prepare a mixed solution. As a result, the mixed solution has an absorption peak in a predetermined wavelength region (specifically, a range of 520 nm ± 10 nm) and is stable (to a degree of deterioration of the plating solution such as a new solution or an aging solution). Regardless, gold colloid is obtained.

  The gold-containing solution used in the present invention is not particularly limited as long as it is a solution containing gold ions. Specific examples include a gold sulfite solution and a chloroauric acid solution.

  A plating solution is a typical example of the gold-containing solution. As described above, the plating solution contains many additives, and details of the plating solution will be described later.

  The reducing agent used in the present invention is not particularly limited as long as it can reduce gold ions in the gold-containing solution and form a gold colloid. Specifically, for example, alkali metal salts of borohydride (for example, sodium borohydride, potassium borohydride, etc.), dimethylamine borane, tin chloride, sodium hypophosphite, sodium L-ascorbate, sodium citrate , Citric acid, iron sulfate and the like. Of these, preferred in terms of color development and measurement sensitivity are alkali metal salts of borohydride (for example, sodium borohydride, potassium borohydride), dimethylamine borane, tin chloride, and more preferably Sodium borohydride and dimethylamine borane. In the examples described later, experiments were conducted using sodium borohydride as a reducing agent, but it was confirmed that similar results were obtained using other reducing agents (for example, dimethylamine borane and tin chloride). ing.

  When an aqueous solution of sodium borohydride, potassium borohydride, or tin chloride is used as the reducing agent, hydrolysis may occur due to the change of the reducing agent over time, and the quality may be lowered. When the method of the present invention is applied to an automatic analyzer, a new reagent such as a reducing agent is not always used, and a reagent stored for one week or more may be used. Therefore, in order to maintain the quality of the reducing agent for a long period of time and to improve the storage state of the reducing agent before adjusting the mixed solution, for example, about 2 to 10 g / L as a quality maintaining agent in the aqueous solution. You may preserve | save by adding sodium hydroxide or hydrochloric acid.

  Furthermore, in the present invention, it is important to use iodide as a reduction aid. In the present invention, the iodide is selected not only to exhibit the promoting action of the reducing agent and not only to be useful as a coloring aid, but also to have the action of adjusting the shift in absorbance due to the new solution and the aging solution. .

  This point will be described in detail. For example, in the case of a plating solution, by-product and the like are generated by repeated use as described above, and the plating solution is deteriorated, so that the conditions for producing the gold colloid also change. When the gold concentration is quantified using, for example, an automatic analyzer (automatic management device), it is necessary to always generate a stable gold colloid under the same conditions without being affected by by-products. According to the examination results of the present inventors, it has been found that the above object can be achieved by using iodide. According to the results of basic experiments by the present inventors, when preparing a mixed solution and using only a reducing agent and no iodide, the absorbance at 530 nm is greatly reduced in the aging solution compared to the new solution, and due to the deterioration of the solution. It turns out that it is greatly affected. Furthermore, it was also found that when the iodide was added to the new solution, the absorbance decreased, and when the iodide was added to the aging solution, the absorbance was improved. In the present invention, the effect of the absorbance peak due to the deterioration of the solution at the time of colloidal gold production has been successfully eliminated by utilizing the action of such an iodide. In the present invention, it is preferable to appropriately control the addition amount of the reducing agent and iodide to be used (details will be described later), and the above object is more effectively exhibited.

The iodide used in the present invention is an iodide having an oxidation number of −1 and may exhibit any of the above functions, and includes iodine itself (I ₂ ). Specifically, in addition to iodine, for example, a salt with an alkali metal (potassium iodide, sodium iodide, etc.) and the like can be mentioned. In consideration of measurement sensitivity and the like, an alkali metal salt of iodine is preferable, and potassium iodide is more preferable.

  Specifically, the reducing agent and iodide are added to the gold-containing solution, and water is added to prepare a mixed solution. In order to obtain the desired gold colloid, it is preferable to appropriately control the amount of these added, thereby preventing the deposited gold from being decomposed and precipitated in the solution by, for example, excessive addition of a reducing agent. be able to.

  Specifically, the preferred concentration of the reducing agent contained in the mixed solution may vary depending on the type and concentration of the reducing aid used, the temperature and time when the mixed solution is prepared, the composition of the plating bath, etc. ~ 0.2 g / L. When the concentration of the reducing agent is less than 0.01 g / L, the reducing action due to the addition of the reducing agent is not exhibited effectively. On the other hand, when the concentration of the reducing agent exceeds 0.2 g / L, gold deposited by excessive addition of the reducing agent is decomposed and precipitated in the solution. The concentration of the reducing agent is more preferably 0.01 to 0.05 g / L, still more preferably 0.02 to 0.03 g / L.

  Moreover, although the preferable density | concentration of the iodide contained in the said mixed solution can change with the kind and density | concentration of the reducing agent to be used, the temperature and time at the time of preparation of mixed solution, a composition of a plating bath, etc., it is 0.5-5. 0 g / L. When the iodide concentration is less than 0.5 g / L, the above-described action due to the addition of iodide is not exhibited effectively. On the other hand, when the iodide concentration exceeds 5.0 g / L, problems such as a decrease in absorbance and fluctuation in peak wavelength occur due to excessive addition of iodide. The concentration of iodide is more preferably 1.0 to 4.0 g / L, still more preferably 1.5 to 3.0 g / L.

  In addition, in the preparation of the mixed solution, the order of adding the gold-containing solution, the reducing agent, and iodide is not particularly limited. However, considering that the colloid becomes unstable when the gold solution and the reducing agent are mixed in a high concentration state, it is preferable to prepare a mixed solution by adding the gold solution, iodide, and reducing agent to the dilution water.

  The temperature and time during the preparation of the mixed solution are not particularly limited, but the temperature is preferably controlled in the range of 20 to 40 ° C., for example, considering the influence of the temperature of the dilution water. In addition, considering the stability of the diluted gold solution, the time is preferably controlled within a range of 5 to 30 minutes, for example.

  In order to prepare a uniform mixed solution, mixing with stirring is recommended.

(Second step)
Next, the gold concentration in the mixed solution thus obtained is measured by an absorbance method in a predetermined wavelength region.

  Here, the predetermined wavelength region specifically means 520 ± 10 nm. That is, in the present invention, the absorbance peak derived from the gold colloid is measured in a wavelength range including a certain allowable range (about 10 nm) around 520 nm.

  The absorbance may be measured immediately after the mixed solution is prepared, or may be measured after being left for a while after the preparation. It has been confirmed by experiments that the time from the preparation of the mixed solution to the measurement of absorbance is preferably not within the range of 10 minutes to 40 minutes, and does not adversely affect the measurement sensitivity.

  If the absorbance in the wavelength range derived from the gold colloid in the mixed solution is obtained in this way, the concentration of the gold colloid in the mixed solution can be calculated based on the known conversion data, and finally, in the gold-containing solution. The gold concentration can be calculated. Specifically, in advance, the relationship between the absorbance obtained as described above and the gold colloid concentration in the mixed solution; the relationship between the absorbance and the gold concentration in the gold-containing solution is examined, and based on these. The gold concentration may be converted and calculated.

  The gold concentration measurement method of the present invention has been described above.

  Next, the measuring apparatus of the present invention will be described. A gold concentration quantification apparatus for quantifying gold concentration in a gold-containing solution according to the present invention includes a reaction vessel for adding and mixing a gold-containing solution, a reducing agent, iodide, and water, and a mixture prepared in the reaction vessel And a spectrophotometer that measures the absorbance of the solution in a predetermined wavelength region.

  The apparatus of the present invention only needs to include at least the reaction vessel and the absorptiometer described above. Furthermore, the apparatus of the present invention includes a gold concentration display device that displays the gold concentration based on the absorbance. May be. The gold concentration display device does not necessarily have to be provided in the same device, and may be provided outside. However, by providing the gold concentration display device in the same device, productivity and the like are improved.

  Specifically, the gold concentration display device includes at least one of a gold concentration display device that displays the gold concentration in the mixed solution and a gold concentration display device that displays the gold concentration in the gold-containing solution. In the former gold concentration display device, the gold concentration in the reaction vessel is displayed. In the latter gold concentration display device, the concentration of the gold-containing solution contained in the gold-containing solution tank represented by the plating tank of FIG. 1 is displayed.

  In addition, the apparatus of the present invention may further include a replenishment amount adjusting device that replenishes a gold-containing component in the gold-containing solution and adjusts the gold concentration in the gold-containing solution in accordance with the absorbance. good. This replenishment amount adjusting device is not necessarily provided in the same device, and may be provided outside, but by providing it in the same device, productivity and the like are improved. By providing such an apparatus, when the gold concentration is insufficient during processing, the gold-containing component can be replenished to the plating tank or the like from the replenishment amount adjusting apparatus.

  Hereinafter, an embodiment of the gold concentration measuring method according to the present invention will be described in detail with reference to the apparatus of FIG. The apparatus of FIG. 1 is an example of an apparatus preferably used in the embodiment of the present invention, and includes the above-described gold concentration display device and replenishment amount adjusting device in addition to the reaction vessel and the absorptiometer. However, the device of the present invention is not intended to be limited to this.

  In FIG. 1, a plating tank (plating bath) contains a metal to be plated and a plating solution. The composition of the plating solution is appropriately determined depending on the type of plating method. The method of the present invention can be applied regardless of the type of plating method [electroplating method, electroless plating method (displacement plating method, reduction plating method)], and the type of plating bath is not particularly limited.

The plating bath used for the displacement plating method (immersion plating method) includes a complexing agent (for example, sodium sulfite), a pH buffering agent (for example, citric acid), etc., in addition to a gold-containing solution containing gold ions. A commercially available plating bath can be used, and examples thereof include TDS-20 bath (Uemura Kogyo Co., Ltd.) and TDS-25. During the plating process, the concentration of the additive in the displacement plating bath may also change. However, in carrying out the method of the present invention, no adverse effect is observed if the concentration of each additive is within the following range. This is confirmed by experiments.
Complexing agent: 10 g / L to 30 g / L
pH buffer: 5 g / L to 40 g / L

In addition to the gold-containing solution containing gold ions, the plating bath used in the reduction plating method (chemical plating method) includes a reducing agent (for example, ascorbic acid), a complexing agent (for example, sodium sulfite), a stabilizer ( For example, 2-amino-4-methylbenzothiazole) and the like are included. A commercially available plating bath can be used, and examples thereof include TMX-15 bath (Uemura Kogyo Co., Ltd.), TMX-16 bath, and the like. The concentration of the additive in the reduction plating bath may also change during the plating process. However, when the method of the present invention is performed, if the concentration of each additive is within the following range, adverse effects are observed. It is confirmed by experiment that there is no.
Reducing agent: 1 g / L to 10 g / L
Complexing agent: 16 g / L to 24 g / L
Stabilizer: 4 g / L to 16 g / L

  Table 1 shows a comparison of the compositions of the displacement plating bath and the reduction plating bath used in the examples described later.

  Specifically, first, a plating solution is sampled from a plating tank and added to a reaction vessel such as a beaker. A small amount of water (for example, ion exchange water) may be added to the beaker in advance.

  Further, a reducing agent solution containing a reducing agent and an iodide solution containing iodide are added, and water (for example, ion-exchanged water) is further added and mixed to adjust the concentration of the mixed solution. Specifically, it is preferable to appropriately control the type and amount of the reducing agent and iodide, the mixing temperature, the standing time, and the like so that an absorbance peak is obtained in a predetermined wavelength region. Thereby, a gold colloid having an absorbance peak in a predetermined wavelength region is obtained.

  Next, the absorbance of the mixed solution thus obtained in a predetermined wavelength region (520 nm ± 10 nm) is measured with an absorptiometer. A commercially available absorptiometer can be used.

  Next, in the gold concentration display device, the gold concentration in the mixed solution corresponding to the absorbance and the gold concentration in the gold-containing solution in the plating tank are displayed from known data obtained in advance. Specifically, calibration curve data indicating the relationship between the absorbance and the gold colloid concentration in the mixed solution is acquired in advance, and based on this, the gold colloid concentration in the mixed solution is calculated. Similarly, calibration curve data indicating the relationship between the absorbance and the gold concentration in the gold-containing solution is acquired in advance, and based on this, the gold concentration in the plating tank can be calculated.

  Next, if it is found from the above results that the gold ion concentration of the sampled plating solution has decreased to below the allowable range, the amount of the gold-containing component to be replenished to the plating tank by the replenishment amount adjusting device. Adjust. Then, the gold-containing component is supplied from the supply amount adjusting device to the plating tank, and the gold concentration in the plating tank is adjusted to a predetermined concentration (concentration at the start of plating).

  Thus, if the apparatus of FIG. 1 is used, not only can the gold concentration during the plating process (the gold concentration in the plating tank) be determined quickly and easily with high accuracy, but also the insufficient gold-containing components can be quickly struck. Therefore, the gold concentration during the plating process can always be kept within a certain range. As a result, a high-quality gold plating film can be obtained stably.

  The technique of the present invention described above can be applied to a commercially available automatic liquid management apparatus. Examples of such a device include CHEMIROBO (registered trademark) (Uemura Industrial Co., Ltd.) and STARLiNE-DASH (registered trademark) (Uemura Industrial Co., Ltd.). These devices automatically sample the plating solution from the electroless gold plating tank, automatically replenish the necessary components according to the analysis results of the main components (Au, reducing agent, reducing aid, etc.), and optimize the plating solution It is very useful as a device that can be maintained in a stable state. If these are used in combination with the apparatus of the present invention, various components including the gold concentration during plating can be managed with high accuracy, which is very useful.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples, and can be implemented with modifications within a range that can meet the purpose described above and below. They are all included in the technical scope of the present invention.

Example 1: Examination of reduction aid In this example, in order to examine the usefulness of iodides (I ₂ and KI) selected as reduction aids, halides other than iodine (KCl, KF, KBr, NaCl) were used. The gold concentration in the gold sulfite plating solution was measured as follows. As the plating bath, the displacement plating bath described in Table 1 above was used.

The following five types of halides were examined in this example.
Kl (5% solution), KCl (5% solution), I ₂ solution (0.05M), KF (5% solution), KBr (5% solution)

  First, 1 mL of a plating solution was collected from a displacement plating bath (Au concentration 2 g / L), added to a 100 mL beaker containing about 50 mL of water, and then 1.7 g / L sodium borohydride (reducing agent) was added. 2 mL of the above-mentioned halide was added as a reducing aid (0 mL) to an appropriate amount (5 mL), and water was added to make 100 mL. The temperature at the time of mixing was room temperature (25 degreeC), and was left to stand for 20 to 50 minutes.

  Next, the absorbance in the wavelength region of 400 to 800 nm was measured using an absorptiometer (SHIMADZU UV-2450, 10 mm quartz cell). These results are shown in FIGS.

Reference is first made to FIG. FIG. 2 shows the results of the absorption spectrum when the standing time after preparation of the mixed solution is 30 minutes (constant). 2A is a 0.05 MI ₂ solution, FIG. 2B is a 5% KI solution, FIG. 2C is a 5% KBr solution, FIG. 2D is a 5% KCl solution, and FIG. Shows the results of 5% NaCl solution, and FIG. 2 (f) shows the results of 5% KF solution.

Focusing on the measurement wavelength region of gold colloid of 520 nm, only when the I ₂ solution [FIG. 2 (a)] and the KI solution [FIG. 2 (b)] are used, compared to the case of no addition of each solution. An increase in absorbance was observed. Specifically, an addition amount of 0.3 to ₁ mL (0.02 to 0.06 g / L in terms of concentration in the mixed solution) is added for the I ₂ solution, and an addition amount (mixing of 0.5 to 5 mL is added for the KI solution). In terms of the concentration in the solution, the absorbance was improved at 0.25 to 2.5 g / L). That is, it was found that the use of the I ₂ solution and the KI solution among the halides used in the experiment promotes the formation of gold colloid.

Reference is now made to FIG. FIG. 3 shows the result of the absorption spectrum when the added amount of halide is 1 mL (constant). 3 (a) is a 0.05 MI ₂ solution, FIG. 3 (b) is a 5% KI solution, FIG. 3 (c) is a 5% KBr solution, FIG. 3 (d) is a 5% KCl solution, and FIG. 3 (e). Shows the results for a 5% NaCl solution, and FIG. 3 (f) shows the results for a 5% KF solution.

From these figures, only when the I ₂ solution [FIG. 3 (a)] and the KI solution [FIG. 3 (b)] are used, the absorbance at 520 nm is 0.4 or more in a short time (20 minutes standing time). It became high. These results show that a stable gold colloid can be obtained in a short time when the iodide is used.

In addition, when the above I ₂ solution and KI solution were used, the same results as above were obtained even when the standing time was extended from 20 minutes to 30 minutes, and further to 50 minutes. Below, it was found that the effect of neglected time is not affected. On the other hand, it can be seen that the solutions other than those described above are greatly affected by the standing time, and the absorbance is not stable [FIGS. 3C to 3F].

  Reference is now made to FIG. In FIG. 4, a KI solution was used as a halide, and the addition amount of the KI solution was 0.5 mL [FIG. 4 (a)], 1 mL [FIG. 4 (b)], 2 mL [FIG. 4 (c)], 3 mL [ FIG. 4 (d)] and 5 mL [FIG. 4 (e)] show the results. Note that FIG. 4B is the same as FIG. 3B described above.

  From these figures, if the addition amount of the KI solution is 1 to 3 mL [FIG. 4 (b) to FIG. 4 (d)] (0.5 to 1.5 g / L in terms of concentration in the mixed solution), It can be seen that a gold colloid having an absorption peak at 520 nm can be obtained in a stable state regardless of the standing time (20 to 50 minutes).

From the above experimental results, it was found that when I ₂ or KI iodide was used as the reducing aid, a stable colloidal gold was formed in a short time by adding a small amount.

Example 2: Examination of preferred addition amount of reducing agent and reducing aid (displacement plating bath)
In this example, regardless of the degree of deterioration of the plating solution (new solution, aging solution), a gold colloid having an absorbance peak at 520 nm can be stably obtained in a short time. A preferred addition amount was examined.

  Specifically, in this example, 1.7 g / L sodium borohydride as a reducing agent, 50 g / L KI solution as a reducing aid, and the same displacement plating bath as in Example 1 were used. The reducing agent contains 5.6 g / L of sodium hydroxide as a quality maintaining agent. The Au concentration in the plating solution (new solution) before the start of plating is 2 g / L (see Table 1). Further, in order to prepare an aging solution, a plating solution (Au concentration 1.9 g / L) having an aging degree of 4 MTO, which was subjected to repeated plating treatment and supplemented with a gold component of 8 g / L was prepared.

  1 mL of each of the above-mentioned new solution and aging solution is collected and added to a 100 mL beaker. Then, 1 to 3 mL of sodium borohydride (reducing agent) and 1 to 4 mL of KI solution (reducing aid) are added, and water is added. To 100 mL. The temperature during mixing was room temperature (25 ° C.) and left for 20 minutes.

  Next, the absorbance in the wavelength region of 400 to 800 nm was measured in the same manner as in Example 1. These results are shown in FIGS. FIG. 5 shows the result of the new solution, and FIG. 6 shows the result of the aging solution. (A), (b), (c), and (d) of FIG. 5 and FIG. 6 show the results when 1 mL, 2 mL, 3 mL, and 4 mL of KI solution were added, respectively. In these figures, sodium borohydride (reducing agent) is represented as S-1 for convenience.

  Reference is first made to FIG. 5 (new liquid). 5A to 5D, in which 3 mL of the KI solution is added, in FIG. 5C, the absorbance near 520 nm regardless of the amount of sodium borohydride added (1 mL, 2 mL, 3 mL). Matched (absorbance ≈ 0.373).

  A similar tendency was also observed in FIG. 6 (aging solution). That is, in FIGS. 6A to 6D, in FIG. 6C in which 3 mL of the KI solution was added, regardless of the amount of sodium borohydride added (1 mL, 2 mL, 3 mL), The absorbance was consistent (absorbance ≈ 0.357).

  From these results, in order to stably obtain a gold colloid having a high peak in the wavelength region of 520 nm in a short time regardless of the new solution or the aging solution under the conditions of this example, KI is used as a reduction aid. 3 mL of the solution was added (1.5 g / L when converted to the concentration in the mixed solution), and 1 to 3 mL of sodium borohydride was added as a reducing agent (0.017 to 0.051 g / when converted to the concentration in the mixed solution). L) is effective.

Example 3: Investigation of mixing temperature and standing time (part 1) (displacement plating bath)
In this example, a gold colloid having an absorbance peak at 520 nm can be stably obtained in a short time regardless of the degree of deterioration of the plating solution (new solution, aging solution), and a preferred temperature during preparation of the mixed solution And the preferred standing time was investigated.

  Specifically, in this example, 1.7 g / L sodium borohydride as a reducing agent, 50 g / L KI solution as a reducing aid, and the same displacement plating bath as in Example 1 were used. The reducing agent contains 5.6 g / L of sodium hydroxide as a quality maintaining agent. As the plating solution, both the same new solution (Au concentration 2 g / L) and aging solution (Au concentration 1.9 g / L) as in Example 2 were used.

  First, 1 mL each of the new solution and the aging solution was collected and added to a 100 mL beaker, then 2 mL of sodium borohydride (reducing agent), 3 mL of KI solution (reducing aid) were added, and water was added to make 100 mL. . The absorbance at 520 nm when the mixing temperature was changed in the range of 15 to 45 ° C. and the standing time after mixing was changed in the range of 5 to 60 minutes at each temperature was the same as in Example 1. The change in absorbance was calculated. Here, “absorbance change” means the ratio of absorbance at each standing time when the value at the time when the peak value is obtained is 100% when there is no fluctuation in absorbance at each temperature during mixing. (%).

  Each of these results is shown in FIG. FIG. 7A shows the result when the mixing temperature is 15 ° C. and the standing time is 10 to 60 minutes; FIG. 7B shows the result when the mixing temperature is 20 ° C. and the standing time is 5 to 40 minutes. FIG. 7 (c) shows the results when the mixing temperature is 25 ° C. and the standing time is 5 to 40 minutes; FIG. 7 (d) shows the results when the mixing temperature is 30 ° C. and the standing time is 5 to 40 minutes. FIG. 7 (e) shows the result when the mixing temperature is 35 ° C. and the standing time is 5 to 40 minutes; FIG. 7 (f) shows the mixing temperature is 40 ° C. and the standing time is 5 to 40 minutes. FIG. 7 (g) shows the results when the mixing temperature is 45 ° C. and the standing time is 5 to 40 minutes, respectively. For reference, FIG. 7A to FIG. 7G each show the value of the standing time when the absorbance is 100%. For example, in FIG. 7 (a), the absorbance when the standing time is 60 minutes is defined as 100%, and the change in absorbance for each standing time is calculated. Similarly, in FIG. 7 (b), the absorbance when the standing time is 25 minutes is 100%; in FIGS. 7 (c) to 7 (e), the absorbance when the standing time is 20 minutes is 100%; In (f), the absorbance at a standing time of 15 minutes was taken as 100%; in FIG. 7 (g), the absorbance at the standing time of 5 minutes was taken as 100%, and the change in absorbance at each standing time was calculated.

  In FIGS. 7A to 7G, the results of the new solution (♦) and the results of the aging solution (■) are shown, respectively.

  From these figures, if the temperature during mixing is in the range of 20 to 35 ° C. and the standing time is in the range of 20 to 40 minutes, the deviation of the absorbance change due to the new solution and the aging solution is generally suppressed within ± 5% and is stable. It can be seen that the absorbance can be obtained in a short time.

Example 4: Examination of mixing temperature and standing time (part 2) (displacement plating bath)
This example was performed from the same viewpoint as that of Example 3 described above except that the experiment method was performed under the following conditions.

  Specifically, in this example, as in Example 3 described above, 1.7 g / L sodium borohydride as the reducing agent, 50 g / L KI solution as the reducing aid, the plating bath is a displacement plating bath, plating As the liquid, both a new liquid (Au concentration 2 g / L) and an aging liquid (Au concentration 1.9 g / L) were used. The reducing agent contains 5.6 g / L of sodium hydroxide as a quality maintaining agent.

  First, 1 mL each of the new solution and the aging solution was collected and added to a 100 mL beaker, then 2 mL of sodium borohydride (reducing agent), 3 mL of KI solution (reducing aid) were added, and water was added to make 100 mL. . 520 nm when the temperature at the time of mixing is changed within the range of 15 to 45 ° C. and the standing time at each temperature is 20 minutes or 30 minutes (in each case, 60 minutes at 15 ° C.) The absorbance at was measured in the same manner as in Example 1, and the change in absorbance was calculated. Here, the “absorbance change” in each case is the ratio (%) of absorbance at each mixing temperature when the absorbance at a mixing temperature of 25 ° C. is 100%.

  These results are shown in Table 2 and FIG. 8 (a) [result of standing time 20 minutes] and Table 3 and FIG. 8 (b) [result of standing time 30 minutes], respectively. In FIGS. 8A and 8B, the results of the new solution (♦) and the results of the aging solution (■) are shown, respectively.

  From these figures, regardless of whether the standing time is 20 minutes or 30 minutes, if the temperature at the time of mixing is in the range of 20 to 30 ° C., the difference in absorbance change is approximately regardless of the new solution and the aging solution. It can be seen that it is suppressed within ± 5%.

  In Examples 1 to 4 described above, the displacement plating bath was used, but the same experiment as described above was also performed in the reduction plating bath. Details are as follows.

Example 5: Examination of addition amount of reducing agent and reducing aid (part 1) (reduction plating bath)
In this example, regardless of the degree of deterioration of the plating solution (new solution, aging solution), a gold colloid having an absorbance peak at 520 nm can be stably obtained in a short time. A preferred addition amount was examined.

  Specifically, in this example, 1.7 g / L sodium borohydride as the reducing agent, 50 g / L KI solution as the reducing aid, and the plating bath described in Table 1 are used as the plating bath. It was. The reducing agent contains 5.6 g / L of sodium hydroxide as a quality maintaining agent. The Au concentration in the plating solution (new solution) before starting plating is 3.2 g / L. Furthermore, in order to prepare an aging solution, a plating solution (Au concentration 3.1 g / L) having an aging degree of 2 MTO, which was repeatedly plated and supplemented with a gold component of 6.4 g / L was prepared.

  0.5 mL of each of the above new solution and aging solution is collected and added to the reaction vessel, and then 0.5 to 3 mL of sodium borohydride (reducing agent) and 1 to 10 mL of KI solution (reducing aid) are added. , Water was added to make 100 mL. The temperature during mixing was room temperature (25 ° C.) and left for 20 minutes.

  Next, the absorbance in the wavelength region of 400 to 800 nm was measured in the same manner as in Example 1. These results are shown in FIGS. FIG. 9 shows the result of the new solution, and FIG. 10 shows the result of the aging solution. Moreover, (a), (b), and (c) of FIG. 9 and FIG. 10 show the results when 3 mL, 5 mL, and 7 mL of the KI solution are added, respectively. FIG. 10 (d) shows the result when 10 mL of the KI solution is added.

  First, refer to FIG. 9 (new liquid). 9 (a) to 9 (c), in FIG. 9 (b) in which 5 mL of the KI solution was added, when the amount of sodium borohydride added was 1 to 1.5 mL, the absorbances in the vicinity of 520 nm coincided. (Absorbance ≈ 0.27). Similarly, in FIG. 9C in which 7 mL of the KI solution was added, the absorbance in the vicinity of 520 nm coincided when the added amount of sodium borohydride was 1 to 1.5 mL (absorbance≈0.26).

  A similar tendency was also observed in FIG. 10 (aging solution). That is, in FIGS. 10 (a) to 10 (d), in FIG. 10 (b) in which 5 mL of the KI solution was added and in FIG. 10 (c) in which 7 mL was added, the addition amount of sodium borohydride (1 mL, 1.. 5 mL), the absorbance at 520 nm was consistent (absorbance ≈ 0.26 for KI solution 5 mL; absorbance ≈ 0.26 for KI solution 7 mL).

  From these results, in order to stably obtain a gold colloid having a high peak in the wavelength range of 520 nm in a short time regardless of whether it is a new solution or an aging solution under the conditions of this example (the standing time is 20 minutes). In addition, 5 to 7 mL of KI solution is added as a reduction aid (2.5 to 3.5 g / L in terms of concentration in the mixed solution), and 1 to 1.5 mL of sodium borohydride as the reducing agent (in the mixed solution) It can be seen that it is effective to add 0.017 to 0.0255 g / L) in terms of the concentration.

Example 6: Examination of addition amount of reducing agent and reducing aid (part 2) (reduction plating bath)
In Example 5 described above, the experiment was performed in the same manner as in Example 6 except that the standing time was 30 minutes.

  These results are shown in FIGS. FIG. 11 shows the result of the new solution, and FIG. 12 shows the result of the aging solution. Moreover, (a), (b), and (c) of FIG. 11 and FIG. 12 show the results when 3 mL, 5 mL, and 7 mL of the KI solution are added, respectively. Moreover, (d) of FIG. 12 has shown the result when 10 mL of KI solutions are added.

  First, refer to FIG. 11 (new liquid). First, in FIG. 11A in which 3 mL of KI solution was added, when the amount of sodium borohydride added was 1 to 1.5 mL, the absorbance in the vicinity of 520 nm coincided (absorbance≈0.26). Similarly, also in FIG. 11B in which 5 mL of the KI solution was added, when the amount of sodium borohydride added was 1 to 1.5 mL, the absorbance in the vicinity of 520 nm coincided (absorbance≈0.27). Similarly, in FIG. 11C in which 7 mL of the KI solution was added, when the amount of sodium borohydride added was 1 to 1.5 mL, the absorbance in the vicinity of 520 nm coincided (absorbance≈0.26).

  A similar tendency was also observed in FIG. 12 (aging solution). That is, in FIG. 12 (a) to FIG. 12 (d), in FIG. 12 (a) in which 3 mL of KI solution is added, in FIG. 12 (b) in which 5 mL of KI solution is added, and in FIG. Regardless of the amount of sodium borohydride added (1 mL, 1.5 mL), the absorbance at 520 nm matched (absorbance ≈ 0.26 for KI solution 3 mL; absorbance ≈ 0.26 for KI solution 5 mL; In the case of 7 mL of KI solution, absorbance ≈ 0.26).

  From these results, in order to stably obtain a gold colloid having a high peak in the wavelength region of 520 nm in a short time regardless of whether it is a new solution or an aging solution under the conditions of this example (the standing time is 30 minutes). Add 3 to 7 mL of KI solution as a reducing aid (1.5 to 3.5 g / L in terms of concentration in the mixed solution), and add 1 to 1.5 mL of sodium borohydride as the reducing agent (mixed solution) It is understood that 0.017 to 0.0255 g / L) is effective when converted to the concentration in the medium.

Example 7: Examination of Addition Amount of Reduction Auxiliary Agent and Standing Time (Part 1) (Reduction Plating Bath)
In Example 5 described above, the amount of addition of the reducing agent (sodium borohydride) was 1 mL or 1.5 mL, and the standing time (20 to 60 minutes) was changed when the KI solution was changed in the range of 3 to 7 mL. The effect was investigated. Here, a new solution (Au concentration 3.2 g / L) was used as the plating solution.

  These results are shown in FIGS. FIG. 13 shows the results for 1 mL of reducing agent, and FIG. 14 shows the results for 1.5 mL of reducing agent. Moreover, (a), (b), (c), and (d) of FIG. 13 and FIG. 14 show the results when 3 mL, 4 mL, 5 mL, and 7 mL of KI solution are added, respectively. In these figures, sodium borohydride (reducing agent) is represented as S-1 for convenience.

  From these results, in order to stably obtain a gold colloid having a high peak in the wavelength region of 520 nm in a short time under the conditions of this example (using a new solution), 4 KI solutions were used as reducing aids. It can be seen that it is effective to add ˜5 mL (2.0 to 2.5 g / L in terms of concentration in the mixed solution) and set the standing time to 30 to 60 minutes.

Example 8: Examination of addition amount and standing time of reducing aid (part 2) (reduction plating bath)
In Example 7 described above, an experiment was performed in the same manner as in Example 7 except that the aging solution was used as the plating solution.

  These results are shown in FIGS. FIG. 15 shows the results for 1 mL of reducing agent, and FIG. 16 shows the results for 1.5 mL of reducing agent. FIGS. 15 and 16 (a), (b), (c), (d), and (e) show the results when the KI solution was added in 3 mL, 4 mL, 5 mL, 7 mL, and 10 mL, respectively. ing.

  From these results, in order to stably obtain a gold colloid having a high peak in the wavelength region of 520 nm in a short time under the conditions of this example (using an aging solution), 3 KI solutions were used as reducing aids. It can be seen that it is effective to add ~ 4 mL (1.5 to 2.0 g / L in terms of concentration in the mixed solution) and set the standing time to 30 to 60 minutes.

Example 9: Investigation of mixing temperature and standing time (Part 1) (Reduction plating bath)
In this example, a gold colloid having an absorbance peak at 520 nm can be stably obtained in a short time regardless of the degree of deterioration of the plating solution (new solution, aging solution), and a preferred temperature during preparation of the mixed solution And the preferred standing time was investigated.

  Specifically, in this example, 1.7 g / L sodium borohydride as a reducing agent, 5 g / L KI solution as a reducing aid, and the same reducing plating bath as in Example 5 were used. The reducing agent contains 5.6 g / L of sodium hydroxide as a quality maintaining agent. As the plating solution, both the same new solution (Au concentration: 3.2 g / L) and aging solution (Au concentration: 3.1 g / L) as in Example 5 were used.

  First, 0.5 mL each of the new solution and the aging solution are collected and added to the reaction vessel, then 1.5 mL of sodium borohydride (reducing agent), 4 mL of KI solution (reducing aid) are added, and water is added. To 100 mL. The absorbance at 520 nm when the mixing temperature was changed in the range of 15 to 40 ° C. and the standing time after mixing was changed in the range of 5 to 60 minutes at each temperature was the same as in Example 1. The change in absorbance was calculated. Here, “absorbance change” is the ratio (%) of absorbance at each standing time when the absorbance at the minimum standing time until the absorbance becomes stable is 100% at each temperature during mixing.

  These results are shown in FIG. FIG. 17A shows the result when the mixing temperature is 15 ° C. and the standing time is 10 to 60 minutes; FIG. 17B shows the result when the mixing temperature is 20 ° C. and the standing time is 10 to 50 minutes. FIGS. 17C and 17D show the results when the mixing temperature is 25 ° C. and the standing time is 10 to 50 minutes; FIG. 17E shows the mixing temperature 30 ° C. and the standing time 10 to 50 minutes; FIG. 17 (f) shows the result when the mixing temperature is 35 ° C. and the standing time is 5 to 40 minutes; FIG. 17 (g) shows the mixing temperature is 40 ° C. and the standing time is 10 to 40. Each result is shown as minutes. For reference, each of FIGS. 17A to 17G shows the value of the standing time when the absorbance is 100%. For example, in FIG. 7 (a), the absorbance at 60 minutes is defined as 100%, and the change in absorbance at each standing time is calculated. Similarly, in FIGS. 17B and 17C, the absorbance when the standing time is 30 minutes is 100%; in FIGS. 17D and 17E, the absorbance when the standing time is 20 minutes is 100%. In FIG. 17 (f) and FIG. 17 (g), the absorbance at the standing time of 10 minutes is defined as 100%, and the change in absorbance at each standing time is calculated.

  In FIGS. 17A to 17G, the result of the new solution (♦) and the result of the aging solution (■) are shown.

  From these figures, if the temperature during mixing is in the range of 25 to 30 ° C. and the standing time is in the range of 20 to 30 minutes, the deviation of the absorbance change due to the new solution and the aging solution can be suppressed within about ± 5%, and the stable absorbance. It can be seen that can be obtained in a short time.

Example 10: Examination of mixing temperature and standing time (part 2) (reduction plating bath)
This example was performed from the same viewpoint as that of Example 9 described above except that the experiment method was performed under the following conditions.

  Specifically, in this example, as in Example 9 described above, 1.7 g / L sodium borohydride as a reducing agent, 5 g / L KI solution as a reducing aid, the plating bath is a reduction plating bath, plating As the liquid, both a new liquid (Au concentration 3.2 g / L) and an aging liquid (Au concentration 3.1 g / L) were used. The reducing agent contains 5.6 g / L of sodium hydroxide as a quality maintaining agent.

  First, 0.5 mL each of the new solution and the aging solution are collected and added to the reaction vessel, then 1.5 mL of sodium borohydride (reducing agent), 4 mL of KI solution (reducing aid) are added, and water is added. To 100 mL. The temperature at the time of mixing was changed in the range of 15 to 40 ° C., and the absorbance at 520 nm was measured in the same manner as in Example 1 when the standing time at each temperature was 20 minutes or 30 minutes. Was calculated. Here, the “absorbance change” in each case is the ratio (%) of absorbance at each mixing temperature when the absorbance at a mixing temperature of 25 ° C. is 100%.

  These results are shown in Table 4 and FIG. 18 (a) [result of standing time 20 minutes] and Table 5 and FIG. 18 (b) [result of standing time 30 minutes], respectively. In FIGS. 18A and 18B, the results of the new solution (♦) and the results of the aging solution (■) are shown, respectively.

  From these figures, regardless of whether the standing time is 20 minutes or 30 minutes, if the temperature at the time of mixing is in the range of 25 to 35 ° C., the difference in absorbance change is approximately ± regardless of the new solution and the aging solution. It turns out that it is restrained within 5%.

Claims (5)

A method for quantifying gold concentration in a plating solution,
Plating solution, a reducing agent, a first step an alkali metal salt of iodine or iodine, and a mixture of water, Ru obtain a mixed solution containing colloidal gold,
A second step of measuring the gold concentration in the mixed solution by an absorbance method at 520 nm ± 10 nm ;
A method for quantifying gold concentration in a plating solution, comprising: The concentration is 0.01~0.2g / L of a reducing agent contained in the mixed solution, to claim 1 the concentration of the alkali metal salt of the iodine or iodine is 0.5 to 5.0 g / L Quantification method of gold concentration as described. A gold concentration quantification device for quantifying gold concentration in a plating solution,
Plating solution, a reducing agent, an alkali metal salt of iodine or iodine, and then mixed with water, a reaction vessel order to obtain a mixed solution containing colloidal gold,
An absorptiometer for measuring the absorbance at 520 nm ± 10 nm of the mixed solution prepared in the reaction vessel;
A gold concentration quantification apparatus comprising: The gold concentration determination device according to claim 3 , further comprising a gold concentration display device that displays a gold concentration in the mixed solution or in the plating solution based on the absorbance. Furthermore, in accordance with the absorbance, gold concentration quantification device according to claim 3 or 4 comprising a supply amount adjusting device for adjusting the concentration of gold plating solution to replenish the gold-containing component in the plating solution.