JP2007101343A - Method, kit, and device for detecting concentration of copper of solder alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of simply calculating the concentration of copper contained in a solder alloy by simple equipment or fixtures, and a kit and a device for easily executing this method. <P>SOLUTION: In the method for detecting the concentration of copper in the solder alloy, (1) the known amount of the target solder alloy is dissolved in an aqueous solution of an inorganic acid, (2) the prepared sample solution is diluted, (3) the diluted solution is mixed with a reaction solution to react with copper ions to form a colored copper complex and a solution of a reaction accelerator to react with them and (4) the absorbance of the reaction product solution is measured and the measuring result is referred to a preliminarily detected result by the same procedure to calculate the concentration of target copper. The kit comprises one set of the aqueous solution of a known concentration of the inorganic acid, a diluting liquid, a reaction solution with known concentration, a reaction accelerator solution and a known amount of a pH adjusting liquid. The device is constituted by holding a very small amount weighing device, an absorbancy measuring instrument and the first-fifth contains constituting the kit in a case body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a copper concentration detection method, kit, and apparatus for a solder alloy.

  At present, printed circuit boards are widely used as electrical circuit devices for electrical products. An actual printed circuit board is usually configured such that various electronic components for mounting are mechanically joined to a circuit of a board made of epoxy resin or ceramic by a solder alloy, and electrical connection is achieved at the same time.

In the past, tin-lead alloys having a ratio of tin component to lead component of about 6: 4 have been used as solder alloys. However, when this electrical product is discarded, this tin-lead alloy is dissolved by rainwater and pollutes groundwater, so that it is a cause of so-called lead damage, and its use is required to be regulated.
For these reasons, recently, various solder alloys called “lead-free solder” not containing a lead component have been developed. Lead-free solder contains tin as a main component and added with additive metal components such as silver, copper, bismuth, and indium. However, as described later, there are still many technical problems.

  Usually, in the process of joining an electronic component to a printed circuit board with a solder alloy, a solder bath containing a molten solder alloy is used in the solder bath, and the electronic component for mounting is combined with the printed circuit board. Is immersed in the molten solder in the solder bath, and the desired joining step is performed.

Thus, with regard to the solder alloy of the solder bath, if the concentration of each metal component composing the solder alloy changes, the characteristics of the solder alloy naturally change, causing various problems. It is important to control the concentration of components.
For example, copper is contained in a specific concentration range as a necessary component in certain solder alloys.

However, since the copper is melted in a considerable proportion in the molten solder alloy of the solder bath from the copper foil used for the pattern wiring of the printed circuit board to be bonded, the molten solder alloy is obtained by repeating the bonding process. The content concentration of copper in the inside becomes gradually higher.
A solder alloy having a high copper concentration usually has a low physical durability, ie, “elongation rate”, and therefore has low mechanical durability. In the printed circuit board having the above, there is a problem that the joint portion easily breaks when stress is applied from the outside due to warpage of the board, for example.

  In addition, the melting point of lead-free solder is usually higher than the melting point of a solder alloy made of a tin-lead alloy, which is about 183 ° C. For example, a typical tin-silver-copper alloy has a melting point of 217 ° C., for example. Then, it is 227 degreeC, for example. A solder alloy having a high copper content has a high liquidus temperature. For example, the solder alloy has a high viscosity even at the same melting temperature. As a result, the desired joining process cannot be achieved with high reliability.

Conventionally, as a method for knowing the content concentration of copper contained in a solder alloy, instrumental analysis and chemical analysis such as X-ray fluorescence analysis and ICP analysis are mainly performed. In order to carry out these analysis methods, a precise and expensive device is required, but it is impractical to install such a device at a site where a solder alloy bonding process is performed.
Under such circumstances, in reality, a sample of a solder alloy is provided to a specialized analysis institution equipped with such an analysis apparatus, and the measurement result of the copper content is obtained. .

  However, in the current method as described above, it takes several days or more for the analysis results to be obtained, apart from the high cost, so it is possible to quickly know the copper content of the solder alloy. Therefore, there is a problem in that it is not possible to perform sufficiently effective management on the state of the solder alloy, and eventually it is impossible to perform the bonding process with high reliability.

  The present invention has been made on the basis of the circumstances as described above, and the object thereof is to obtain the copper content concentration easily and in a short time for a solder alloy with simple equipment or equipment. An object of the present invention is to provide a method for detecting the copper concentration of a solder alloy.

  It is another object of the present invention to provide a solder alloy copper concentration detection kit that allows the above-described method for detecting a copper concentration of a solder alloy to be easily carried out.

  Still another object of the present invention is to provide an apparatus for detecting the copper concentration of a solder alloy that makes it possible to easily carry out the above-described method for detecting the copper concentration of a solder alloy.

The copper concentration detection method of the solder alloy of the present invention,
(1) Dissolve a known amount of a sample of a solder alloy whose copper concentration should be known in an aqueous solution of an inorganic acid,
(2) Dilute the resulting sample solution with a diluent,
(3) The resulting diluted solution is mixed with a reaction solution containing a ligand compound that reacts with copper ions to form a colored copper complex and a solution of a reducing reaction accelerator, and reacted.
(4) The absorbance of the obtained reaction product solution is measured, and the measurement result is compared with the calibration result obtained in advance by the same procedure for the solder alloy whose copper concentration is known, thereby the solder alloy. The content concentration of copper in the sample is determined.

  In the above, 5,10,20-tetraphenyl-21H, 23H-porphine tetrasulfonic acid disulfate hydrate is used as the ligand compound contained in the reaction solution, and the reaction is carried out at pH 3-7. It is preferable. Ascorbic acid can be used as the reaction accelerator.

  The measurement of the absorbance of the reaction product solution is preferably performed by determining the absorbance of light having a wavelength of 413 nm in a state where the pH of the reaction product solution is 3 or less.

The solder alloy copper concentration detection kit of the present invention is a kit used for carrying out the above-described solder alloy copper concentration detection method,
(A) a first container containing a known amount of an aqueous solution of an inorganic acid of known concentration;
(B) a second container containing a known amount of diluent,
(C) a third container containing a known amount of a reaction solution of known concentration;
(D) a fourth container containing a known amount of reaction accelerator;
(E) The fifth container in which a known amount of the pH adjusting solution is accommodated is a set.

An apparatus for detecting the copper concentration of a solder alloy according to the present invention comprises a case body, a microweigher provided in the case body, and an absorbance measuring device provided in the case body,
The case body is characterized in that a container holding portion for holding the first container to the fifth container constituting the kit is formed.

  According to the copper concentration detection method of the solder alloy of the present invention, it is only necessary to use a very small amount of sample, and a complicated operation requiring high skill and skill is unnecessary. As a result, the copper concentration of the target solder alloy can be known within a short time.

  According to the kit for detecting the copper concentration of the solder alloy of the present invention, since a plurality of necessary reagents are provided in known concentrations or amounts, the copper concentration detection of the above-described solder alloy can be performed by a very simple operation. The method can be carried out.

  According to the apparatus for detecting a copper concentration of a solder alloy of the present invention, the above-described method for detecting a copper concentration of a solder alloy can be carried out very simply.

Hereinafter, an example of implementation of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a conceptual diagram showing an example of the configuration of the apparatus for detecting a copper concentration of a solder alloy according to the present invention. The apparatus 10 is configured by providing a case body 12 with a microweigher 14, which is usually called an chemical balance, and an absorbance measuring device 16 arranged in the upper region of the case body 12. The absorbance measuring device 16 includes a light source 16A, a band-pass filter 16B having a high transmission wavelength region at a wavelength of 413 nm, a measurement cell 16C, and a light receiving element 16D. Reference numeral 16E denotes a display unit.

  In the lower region of the case body 12, five container holding portions HA to HE for receiving and holding a first container to a fifth container described later are formed in an open state. Furthermore, a syringe 18 that collects a trace amount of liquid and supplies it to an appropriate location is detachably provided at the bottom of the case body 12.

  Then, the following five liquids, that is, five containers each containing a predetermined amount of liquid A to liquid E, that is, the first container to the fifth container are prepared, and these containers are the five containers in the case body 12. The holders HA to HE are detachably held. Here, each of the first container to the fifth container is a container having a cap that can be freely opened and closed.

[First container]
Liquid A Aqueous solution of inorganic acid (1: 1: 8 solution of sulfuric acid, nitric acid and pure water) 5 mL
[Second container]
B liquid Diluent (pure water) 25mL
[Third container]
Solution C Pure water was added to 4 mg of the reaction solution (5,10,20-tetraphenyl-21H, 23H-porphine tetrasulfonic acid disulfate hydrate (abbreviated as “TPPS”) and 7.7 g of ammonium acetate. In addition, the solution made 1000mL) 30mL
[Fourth container]
Liquid D Reaction accelerator solution (solution obtained by adding pure water to 53 g of ascorbic acid to make 1000 mL) 10 mL
[Fifth container]
Solution E pH adjustment solution (solution having the same composition as solution A) 2 mL

The TPPS composing the solution C (reaction solution) is a ligand compound that reacts with copper ions to form a colored copper complex, and is represented by the following structural formula (1).
The ammonium acetate contained in the liquid C is a reaction accelerator that promotes the reaction between copper ions and TPPS.

  By using the above-described apparatus for detecting the copper concentration of a solder alloy, the following first to fourth operations are performed, whereby the solder alloy whose concentration of copper should be known (hereinafter referred to as “target solder alloy”). ), The copper concentration can be determined.

First operation (preparation of sample solution)
This first operation is an operation for collecting a known amount of a sample of the target solder alloy and preparing a solution thereof.
[Weighing sample]
For example, a sample of 1 to 20 mg is collected by scraping off the target solder alloy, and the mass of the sample is measured by the micrometer 14. A small amount of this sample is preferable because the required time is shortened.
[Dissolution of sample]
On the other hand, a beaker having a capacity of, for example, 50 mL is prepared, and all of the A solution (5 mL of an inorganic acid aqueous solution) taken out from the case body 12 is put in this beaker. A sample solution is prepared by adding the sample and dissolving it completely.
In preparing the sample solution, in order to completely dissolve the sample in a short time, for example, the system can be heated, stirred, or vibrated.

Second operation (preparation of a diluted sample solution)
[Dilution of sample solution]
The second container is taken out from the case body 12, and all of the liquid B (diluted solution 25mL) is added to the sample solution obtained by the first operation to prepare a diluted sample solution (30mL). In the preparation of the diluted solution of this sample, stirring is performed as necessary.

Third operation (copper complex formation reaction)
[Execution of copper complex formation reaction]
Separately, prepare a beaker with a capacity of, for example, 50 mL, and put all the C solution (30 mL of reaction solution) in the third container taken out from the case body 12 into this C solution. 1 mL of the diluted solution of the obtained sample is added using the syringe 18 provided in the case body 12, and all the D solution (10 mL of the reaction accelerator solution) in the fourth container taken out from the case body 12 is added. Add, stir and react. The reaction is complete in about 5 minutes.
In this operation, it is necessary that the amount of the diluted solution of the sample to be added be a strictly defined amount.
It is preferable that the production | generation reaction of the copper complex by this 3rd operation shall be pH 3-7. According to the above conditions, the pH of the system is about 4.

Fourth operation (measurement of absorbance)
[Preparation of absorbance measurement sample] To the reaction product solution obtained by the third operation, all of the E solution (2 mL of pH adjusting solution) taken out from the case body 12 was added and stirred. Prepare an absorbance measurement sample having a pH of 3 or less. According to the above conditions, the pH of the absorbance measurement sample is about 1, but it is preferable that the absorbance measurement is performed in a state where the absorbance measurement sample is set to pH 3 or less as described later.
(Measurement of absorbance)
The obtained absorbance measurement sample is filled in the measurement cell 16C, and this is set in the absorbance measuring device 16 provided in the case body 12, and the absorbance of the absorbance measurement sample with respect to light having a wavelength of 413 nm is measured. The measurement result is displayed on the display unit 16E.

[Acquisition of copper concentration]
The absorbance value of the obtained measurement result is compared with the calibration result obtained in advance, whereby the concentration of copper contained in the target solder alloy can be known.

In the first operation described above, the aqueous solution of the inorganic acid is not limited to the composition of the liquid A, and may be any solution as long as the target solder alloy is dissolved.
Further, in the second operation, the sample solution is diluted with the diluent, and this dilution makes it possible to cause the reaction with the reaction solution in the third operation smoothly and in a short time. The diluent used in the second operation is not limited to pure water, and may be a solution of an appropriate substance as long as it does not affect the formation of the copper complex.

In the third operation, a colored complex formation reaction between TPPS and copper ions occurs, but the reaction product shows a specific absorption spectrum, and its absorbance measured in the fourth operation is contained. It depends on the concentration of the complex compound.
Therefore, instead of the target solder alloy, by performing the first operation to the fourth operation according to the same conditions for each of various standard samples whose copper concentration is known and the concentration is different, Since it is possible to obtain information on the absorbance according to the copper content, if a calibration curve showing the relationship of the absorbance to the copper content is prepared based on the calibration result, for example, by contrasting with this, From the absorbance value of the target solder alloy whose copper content concentration is unknown, the copper content concentration of the target solder alloy can be obtained.

For example, five types of tin-silver solder alloys whose copper component concentrations are different from 0% by mass, 0.5% by mass, 0.75% by mass, 1.0% by mass, and 1.25% by mass are standard samples. 6.6 mg of each was weighed and dissolved in 5 mL of the above solution A to prepare a standard sample solution, which was diluted with 25 mL of solution B to prepare a diluted standard sample solution, and 1 mL was collected. Then add 10 mL of D solution and add 10 mL of D solution and let stand for 5 minutes, then add 2 mL of E solution to prepare an absorbance measurement sample, and measure the absorbance with respect to the light having a wavelength of 413 nm with an absorbance meter. A calibration curve can be created by measuring and expressing the relationship between the copper concentration and the absorbance measurement value in a curve diagram.
Actually, taking into account the influence of measurement error, it is preferable to prepare an absorbance measurement sample for each standard sample and measure the absorbance thereof, for example, five times, and adopt the average value.

  In the present invention, as a ligand compound that forms a colored copper complex by reacting with copper ions contained in the reaction solution, 5,10,20-tetraphenyl-21H represented by the above structural formula (1) is used. , 23H-porphine tetrasulfonic acid disulfate hydrate is preferably used. This compound reacts with copper ions to form a copper complex represented by the following structural formula (2). As described above, this reaction proceeds smoothly at pH 3-7.

In the fourth operation, the reason for adding the pH adjusting solution in order to prepare the absorbance measurement sample is as follows.
Absorbance measurement obtained by performing the same operation as the first to fourth operations using a standard sample having a copper content of 0.5% by mass and a control sample having a copper content of 0% by mass. FIG. 2 shows the absorbance characteristic curve in the wavelength region of 400 to 450 nm obtained by measurement under the condition that the pH is 1 for the sample. Curve a is for a standard sample A made of a tin-silver-copper solder alloy of 3.0% by mass of silver and 0.5% by mass of copper, and curve b is 3.5% by mass of silver and 0% by mass of copper. % For control sample B consisting of% tin-silver solder alloy.
From this curve diagram, it is understood that the absorbance of the standard sample A is clearly higher at the wavelength of 413 nm than that of the control sample B.
The standard sample A has a high absorbance at a wavelength of 434 nm, but the control sample B also has a high absorbance at a wavelength of 434 nm. Therefore, the copper content obtained from the absorbance at this wavelength is contained. The concentration is not reliable.

  FIG. 3 is the same as FIG. 2 except that the standard solution A and the control sample B similar to those in FIG. 2 were not added with the E solution (pH adjusting solution) in the fourth operation. This is the result obtained. That is, the absorbance measurement sample in the case of FIG. 3 is subjected to absorbance measurement under the condition of pH 4. 2, the curve a corresponds to the standard sample A, and the curve b corresponds to the control sample B.

As apparent from FIG. 3, under the condition where the pH is 4, a high absorbance due to the standard sample A appears at the position of the wavelength 413 nm. At the same time, the control sample B also has an absorption peak at the position of the wavelength 413 nm. Have. This is due to the influence of TPPS that was not involved in the formation of the copper complex, and causes a large error in the measurement of the absorbance of the standard sample A.
On the other hand, under the condition of pH 1, as is clear from FIG. 2, the control sample B does not show a particular peak at a wavelength of 413 nm. Therefore, by measuring the absorbance of the standard sample A at a wavelength of 413 nm, The influence of TPPS on the reaction can be made as small as possible, and as a result, the absorbance measurement value for light with a wavelength of 413 nm is higher to the extent corresponding to the concentration of the produced copper complex, The obtained absorbance measurement value is highly reliable in relation to the copper concentration.

  As described above, the absorption wavelength of the unreacted TPPS can be shifted from 413 nm to 434 nm by changing the pH 4 reaction product solution to pH 1 with the pH adjusting solution. Thus, the light absorbency of can be made highly reliable.

Although the present invention has been specifically described above, in the present invention, if the sample concentration in the absorbance measurement sample, that is, the concentration of the target solder alloy can be obtained, the sample concentration and the measured absorbance value can be obtained. Based on the above, the content of copper in the target solder alloy of the sample can be obtained by comparing with the calibration result obtained in advance.
Accordingly, the type, concentration and amount of the aqueous solution (solution A) of the inorganic acid that dissolves the target solder alloy, and the type, concentration and amount of the diluent (solution B) for diluting the sample solution are not particularly limited. May be used in known concentrations and in known amounts, respectively.

The kind, concentration and amount of the ligand compound contained in the reaction solution (C solution) are not particularly limited, and may be used at a known concentration and a known amount. However, the reaction solution needs to be used in an amount that is equal to or greater than the amount in which all copper contained in the target solder alloy forms a complex.
In this reaction solution, a part of the reaction accelerator (ammonium acetate in the above example) can be contained together as in the above example, but the reaction accelerator is different from the reaction solution. It can also be used as a separate solution.

The reaction accelerator solution (solution D) is necessary for smoothly progressing the actual reaction, but the concentration and amount thereof are not limited. The same applies to the reaction accelerator contained in the reaction solution.
Further, the type, concentration and amount of the pH adjusting liquid are not limited, but it is important that the pH adjusting liquid has an appropriate pH.

  In the present invention, as a ligand compound constituting the reaction product solution and reacting with copper ions to form a colored copper complex, in addition to the above TPPS, α, β, γ, δ-tetraphenylporphine triphenyl is used. Sulfonic acid disulfate hydrate (also sometimes referred to as “TPPS”) can be used.

  As described above, the method for detecting the copper concentration of a solder alloy according to the present invention requires only a very small amount of sample and does not require a complicated operation requiring a high level of skill. As a result, the copper content of the target solder alloy can be known within a short period of time, and this solder is very advantageous at the site where the solder alloy bonding process is performed. The copper concentration of the alloy can be determined.

  In the apparatus for detecting the copper concentration of the solder alloy of the present invention, an aqueous solution of an inorganic acid, a diluting solution, a reaction solution, a reaction accelerator, which are reagents necessary for carrying out the above-described method for detecting the copper concentration of the solder alloy The five types of solution and pH adjusting solution are respectively defined as A solution, B solution, C solution, D solution and E solution in the first container, the second container, the third container, and the fourth container. Since the kit is configured as a set, the sample is only weighed as a sample to be dissolved in the liquid A. Since the elements necessary for calculating the concentration of other absorbance measurement samples are fixed, the concentration of the absorbance measurement sample can be determined from the obtained absorbance measurement value using a certain calculation formula. Determine the copper content of the target solder alloy Easily Te fit, and it can be determined accurately.

  Furthermore, according to the apparatus for detecting the copper concentration of the solder alloy of the present invention, the sample for the target solder alloy is weighed together with the container holding part for holding the first container to the fifth container constituting the kit. Since the microweighing device and the absorbance measuring device are provided in the case body, the copper concentration of the target solder alloy can be obtained very simply.

  Then, information on the calibration result obtained in advance, specifically, calibration curve information, is stored in an appropriate storage device, and the absorbance measurement value information is processed using this, for example, the absorbance measuring device 16. It is also possible to display the copper concentration directly on the display unit 16E.

It is a conceptual diagram which shows an example of a structure of the copper concentration detection apparatus of the solder alloy of this invention. Absorbance characteristic curve in a wavelength region of 400 to 450 nm measured under the condition of pH 1 for a standard sample having a copper content of 0.5% by mass and a control sample having a copper content of 0% by mass FIG. FIG. 4 is an absorbance characteristic curve diagram in a wavelength range of 400 to 450 nm measured under the condition of pH 4 for a standard sample and a control sample similar to those in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Solder alloy copper concentration detection apparatus 12 Case body 14 Micro weighing device 16 Absorbance measuring device 16A Light source 16B Band pass filter 16C Measurement cell 16D Light receiving element 16E Display part HA-HE Container holding part 18 Syringe

Claims (6)

(1) Dissolve a known amount of a sample of a solder alloy whose copper concentration should be known in an aqueous solution of an inorganic acid,
(2) Dilute the resulting sample solution with a diluent,
(3) The resulting diluted solution is mixed with a reaction solution containing a ligand compound that reacts with copper ions to form a colored copper complex and a solution of a reducing reaction accelerator, and reacted.
(4) The absorbance of the obtained reaction product solution is measured, and the measurement result is compared with the calibration result obtained in advance by the same procedure for the solder alloy whose copper concentration is known, thereby the solder alloy. A method for detecting a copper concentration in a solder alloy, comprising: determining a copper concentration in the sample.   The ligand compound contained in the reaction solution is 5,10,20-tetraphenyl-21H, 23H-porphine tetrasulfonic acid disulfate hydrate, and the reaction is carried out at pH 3-7. The method for detecting a copper concentration in a solder alloy according to claim 1.   The method according to claim 1 or 2, wherein the reaction accelerator is ascorbic acid.   The absorbance of the reaction product solution is measured by determining the absorbance of light having a wavelength of 413 nm in a state where the pH of the reaction product solution is 3 or less. The method for detecting the copper concentration of the solder alloy as described. It is a kit used for implementation of the copper concentration detection method of the solder alloy according to any one of claims 1 to 4,
(A) a first container containing a known amount of an aqueous solution of an inorganic acid of known concentration;
(B) a second container containing a known amount of diluent,
(C) a third container containing a known amount of a reaction solution of known concentration;
(D) a fourth container containing a known amount of reaction accelerator;
(E) A copper concentration detection kit for a solder alloy, characterized in that a set of a fifth container containing a known amount of a pH adjusting solution is set. A case body, a microweigher provided in the case body, and an absorbance measuring device provided in the case body,
Solder alloy, wherein the case body is formed with a container holding portion for holding the first container to the fifth container constituting the kit for detecting the copper concentration of the solder alloy according to claim 5. For copper concentration detection.

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