JP3824021B1 - Solder material inspection method, solder material inspection device, control program, and computer-readable recording medium - Google Patents

Abstract

To provide a viscosity measuring device and a viscosity measuring method capable of measuring the viscosity of a solder material in a short time without causing deterioration of the solder material.
The infrared spectroscopic measurement unit detects a first intensity of infrared light of a specific wave number reflected from the solder material to be inspected by irradiating light to the solder material to be inspected, and the solder material to be compared The second intensity of the infrared of the specific wave number that reflects the solder material to be compared is detected by irradiating the light with the light. Then, the calculation unit 10 calculates the viscosity of the solder material to be inspected by substituting the first infrared absorbance into the calibration curve equation specified based on the second infrared absorbance.
[Selection] Figure 1

Description

  The present invention relates to a solder material inspection method and a solder material inspection apparatus for inspecting the viscosity of a solder material.

  In a printed circuit board production line, by performing a printing process for printing a solder material on a board, a mounting process for mounting an electronic component on the printed solder material, and a reflow process for soldering the electronic component to the board, Electronic components are mounted on the board.

  In the printing process described above, the solder material is placed on the surface of a metal mask arranged on the substrate. This metal mask has an opening corresponding to the wiring pattern. The solder material rotates on the surface of the metal mask by being pressed by a moving squeegee. Further, the rotating solder material is pushed out from the opening hole onto the substrate by the pressing force of the moving squeegee. Thereby, the solder material is printed on the substrate.

  This metal mask is continuously used for a large number of substrates while the same solder material is placed thereon. Therefore, the solder material is repeatedly rotated by the moving squeegee every time the printing is repeated. Here, due to this rotational movement, the solder material gradually deteriorates and its viscosity increases. The solder material having a high viscosity due to deterioration becomes a factor causing defects in the printed circuit board.

  That is, it is known that when the solder material printed on the substrate has a high viscosity, defects such as “debris” and “scratch” are likely to occur in the substrate after the printing process. For this reason, it is important to analyze the viscosity of the solder material to be supplied before supplying the solder material onto the metal mask.

  As an apparatus for measuring the viscosity of a solder material, there is conventionally an apparatus (for example, a PCU-200 series manufactured by Malcolm Co., Ltd.) that stirs a cream-like solder material with a spiral wing called a rotor.

Patent Document 1 discloses a method for measuring the viscosity of a solder material based on the flow rate of the solder material flowing on the squeegee surface.
JP-A-5-99831 (Publication date: April 23, 1993) Japanese Patent Publication No.8-20434 (Public Notice: March 04, 1996) JP 10-82737 A (publication date: March 31, 1998)

In an apparatus that stirs a solder material with a rotor and measures its viscosity, the following problems (A) to (D) exist.
(A) All pots of cream solder are required for viscosity measurement.
(B) When the viscosity is measured, the solder material is deteriorated by stirring the solder material.
(C) The viscosity measurement takes a relatively long time of about 30 minutes.
(D) Since cream solder adheres to the rotor, it takes a lot of time to clean the equipment.

  In addition, the method disclosed in Patent Document 1 can measure the viscosity of the solder material only when the squeegee is driven, and there is a problem that the inspection object is limited to only the solder material being used in the printing process.

  Therefore, Patent Document 2 discloses a method of measuring the acidity of a solder material (flux) by performing titration using a sampled solder material. However, this method has a problem that work such as reagent adjustment takes time.

  Patent Document 3 discloses a technique for measuring the surface oxidation rate of a solder material by ultraviolet photoelectron spectroscopy. However, this method is not preferable in terms of work hygiene because it uses ultraviolet rays harmful to the human body.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a viscosity measuring apparatus and a viscosity measuring device capable of measuring the viscosity of a solder material in a short time without causing deterioration of the solder material. To realize the method.

  In order to achieve the above object, the solder material inspection method of the present invention detects the first intensity of infrared light of a specific wave number reflected from the solder material to be inspected by irradiating the solder material to be inspected with light. A first detection step; a second detection step of detecting a second intensity of the infrared of the specific wave number reflected from the solder material to be compared by irradiating the solder material to be compared; and the detected And an inspection step of inspecting the viscosity of the solder material to be inspected based on the first and second strengths.

  It is known that a good-quality solder material has a low viscosity, a low oxidation degree, and a high reducing power, and when the solder material is deteriorated, the viscosity / oxidation degree is increased and the reducing power is lowered. Therefore, the degree of deterioration of the solder material can be determined from at least one item of the viscosity, the degree of oxidation, and the reducing power of the solder material.

  Here, the inventors of the present application examined a technique that is different from the prior art and that can analyze the viscosity of the solder material. The inventors of the present application have found that the viscosity of the solder material can be analyzed by using infrared spectroscopy as a result of diligent efforts.

  Hereinafter, the reason why the viscosity of the solder material can be analyzed by infrared spectroscopy will be described in detail.

  When the solder material is continuously used and the solder material is continuously exposed to the outside air, the contained metal is oxidized in the solder material, and the contained acid (for example, carboxylic acid) is changed into a salt. That is, when a solder material is used or exposed to the outside air, the content of metal oxides in the solder material increases, the acid content decreases, and the salt content increases.

  The increase in the metal oxide increases the degree of oxidation of the solder material, the increase in salt increases the viscosity of the solder material, and the reduction of the acid content decreases the reducing power of the solder material.

  Therefore, if the contents of acid and salt in the solder material to be inspected can be analyzed, the viscosity of the solder material can be inspected, and consequently the degree of deterioration of the solder material can be inspected. That is, the acid content and the salt content in the solder material indicate the degree of deterioration of the solder material.

  Here, the present inventors have realized that the present invention can be realized by focusing on the fact that at least one item of acid and salt content can be analyzed according to infrared spectroscopy.

  Specifically, in the present invention, by irradiating light to the solder material to be inspected, the first intensity of infrared of a specific wave number reflected from the solder material to be inspected is detected, and the above-mentioned light is applied to the solder material to be compared. , The second intensity of the infrared of the specific wave number that reflects the solder material to be compared is detected.

  Here, depending on the content of acid and salt in the solder material, the infrared ray absorption amount of the specific wave number in the solder material changes, and the intensity of the specific wave number of the infrared ray reflected from the solder material changes. This is because the acid and salt contained in the solder material have the property of absorbing infrared rays in the wave number band specified in each.

  Therefore, based on the first intensity of the specific wave number of infrared light that reflects the solder material to be inspected and the second intensity of the specific wave number of infrared light that reflects the solder material to be compared, the acid in the solder material to be inspected The salt content can be analyzed, whereby the viscosity of the solder material to be inspected can be inspected. Therefore, the degree of deterioration of the solder material to be inspected can be inspected.

  In the solder material inspection method of the present invention, the light applied to the solder material may be the infrared light with the specific wave number or the light containing the infrared light with the specific wave number.

  In addition, according to the solder material test | inspection method of this invention shown above, since the titration operation | work currently disclosed by patent document 2 is unnecessary, the effort on operation | work can be suppressed rather than the method of patent document 2. FIG. In addition, the solder material inspection method of the present invention described above does not use ultraviolet rays, and therefore is more preferable in view of work hygiene than the method of Patent Document 3.

  In order to achieve the above object, the solder material inspection apparatus according to the present invention includes a light source that irradiates light to a solder material to be inspected and a solder material to be compared, and an object to be inspected by irradiating the light. Intensity detecting means for detecting a first intensity of infrared of a specific wave number reflected from the solder material, and detecting a second intensity of infrared of the specific wave number reflected from the solder material to be compared by being irradiated with the light; Control means for outputting the viscosity of the solder material to be inspected based on the detected first and second strengths.

  According to the above configuration, the intensity detection means detects the first intensity of the specific wave number of infrared rays reflected from the solder material to be inspected by irradiating light from the light source, and compares it by irradiating the light from the light source. The second intensity of infrared rays of a specific wave number reflected from the target solder material is detected.

  Here, the intensity of the specific wave number of infrared rays reflected from the solder material changes according to the content of acid and salt in the solder material. This is because the acid and salt contained in the solder material have the property of absorbing infrared rays in the wave number band specified in each.

  Therefore, based on the first intensity of the specific wave number of infrared light that reflects the solder material to be inspected and the second intensity of the specific wave number of infrared light that reflects the solder material to be compared, the acid in the solder material to be inspected The content of salt can be determined. Here, the content indicates the degree of deterioration of the solder material.

  Therefore, in the above configuration, the content is output as the viscosity of the solder material to be inspected. Thereby, the user of this apparatus can analyze the output viscosity and can inspect the deterioration degree of the solder material to be inspected.

  Further, in the solder material inspection method of the present invention, it is only necessary to analyze at least one item of acid and salt content. Therefore, the specific wave number is the wave number included in the infrared wave number band absorbed by the acid included in the solder material. It may be. And as said acid, it is preferable that it is carboxylic acid. This is because a carboxylic acid is mentioned as an acid with much content among the acids contained in a solder material.

Carboxylic acid has a property of absorbing infrared rays of 1665 cm ^{−1 to} 1730 cm ⁻¹ . Therefore, the specific wave number is preferably a wave number included in a range of 1665 cm ^{−1 to} 1730 cm ⁻¹ .

  Furthermore, in the solder material inspection method of the present invention, it is only necessary to analyze at least one item of acid and salt content. Therefore, the specific wave number is the wave number included in the infrared wave number band absorbed by the salt included in the solder material. It may be. And as said salt, it is preferable that it is carboxylate. This is because a carboxylate is mentioned as a salt with much content among the salts contained in the deteriorated solder material.

Incidentally, carboxylate ^has a property to absorb an infrared ray at 1270cm ^-1 ~1430cm -1. Therefore, the specific wave number is preferably a wave number included in a range of 1270 cm ^{−1 to} 1430 cm ⁻¹ . Also, carboxylate ^has a property to absorb an infrared ray at 1500 cm -1 1650 cm ^-1. Therefore, the particular wave number ^is preferably a wave number included in a range of 1500 cm -1 1650 cm ^-1.

  The control means may be realized by a computer. In this case, a control program for realizing the control means by a computer and a computer-readable recording medium on which the control program is recorded are the present invention. It falls into the category.

  As described above, in the solder material inspection method of the present invention, the first detection step of detecting the first intensity of infrared of a specific wave number reflected from the solder material to be inspected by irradiating the solder material to be inspected with light. A second detection step of detecting the second intensity of the infrared of the specific wave number reflected from the solder material to be compared by irradiating the solder material to be compared with the light; and the first and second detected And an inspection step of inspecting the viscosity of the solder material to be inspected based on the two strengths.

  Therefore, it is possible to analyze the contents of acids and salts contained in the solder material to be inspected, and thereby to inspect the viscosity of the solder material to be inspected. Therefore, the deterioration degree of the solder material to be inspected can be inspected.

In the solder material inspection method and the solder material inspection apparatus, the solder material viscosity is detected by irradiating light to the solder material to be inspected and the comparison target, and the viscosity of the solder material is stirred by the rotor. Compared to the conventional method of measuring, the following advantages (A) to (D) are obtained.
(A) Only a small amount of cream solder is used for inspection.
(B) It is not necessary to stir the solder material at the time of inspection, and the solder material is not deteriorated.
(C) The measurement time is as short as about 30 seconds.
(D) Since it is only necessary to wipe off the solder material on the plate, the device can be cleaned in a short time.

[Solder Material Inspection Method]
The solder material inspection method in the present embodiment is a method for inspecting the viscosity of a solder material using infrared rays. The “solder material” in the present embodiment means a cream-like solder paste used in a printed circuit board production line, but the present invention is not limited to this solder paste, It is applicable to all known solder materials.

  Details of the solder material inspection method of this embodiment will be described below.

  When the solder material is continuously used and the solder material is continuously exposed to the outside air, the contained metal is oxidized in the solder material, and the contained carboxylic acid is changed to a carboxylate. That is, when a solder material is used or exposed to the outside air, the contained metal oxide increases, the contained carboxylic acid decreases, and the contained carboxylate increases in the solder material.

  A phenomenon in which the increase in the metal oxide increases the degree of oxidation of the solder material, the increase in the carboxylate increases the viscosity of the solder material, and the reduction in the content of carboxylic acid decreases the reducing power of the solder material. Occurs. Such a phenomenon is called solder material deterioration.

  Therefore, if at least one of the content of carboxylic acid and the content of carboxylate can be analyzed in the solder material to be inspected, the viscosity of the solder material can be inspected, and consequently the degree of deterioration of the solder material can be inspected. .

  On the other hand, it is known that each of the carboxylic acid and the carboxylate salt absorbs infrared rays in a specific wave number band specified in each.

  Therefore, the solder material inspection method of the present embodiment is realized by combining the following steps. First, a first detection step of detecting a first intensity of infrared rays having a specific wave number reflected from the solder material to be inspected by irradiating light to the solder material to be inspected is performed. Next, a second detection step of detecting a second intensity of the infrared of the specific wave number that reflects the solder material to be compared by irradiating the solder material to be compared with the light is performed. And based on each detected intensity | strength, the test process which test | inspects the viscosity of the solder material of the said test object is implemented. The first detection step and the second detection step may be performed in reverse order or simultaneously.

  According to the solder material inspection method of the present embodiment described above, the first detection step and the second detection step reflect the first intensity of the specific wave number of infrared rays reflected from the inspection target solder material and the comparison target solder material. The second intensity of the specific wave number of infrared rays to be detected can be detected.

  Here, as described above, each of the carboxylic acid and the carboxylate salt absorbs infrared rays in a specific wave number band specified in each. Therefore, depending on the content of the carboxylic acid and carboxylate in the solder material, the amount of infrared rays absorbed at a specific wave number in the solder material changes, and the intensity of the infrared ray at a specific wave number that reflects the solder material changes.

  Therefore, based on each intensity detected in the first and second detection steps, at least one of the content of carboxylic acid and the content of carboxylate in the solder material to be inspected can be analyzed. Therefore, the viscosity of the solder material to be inspected can be inspected.

  As an aspect of the inspection step, the viscosity V of the solder material to be inspected can be obtained using a calibration curve equation shown in the following equation (1).

V = aA ² + bA + c (1)
In the calibration curve equation, a, b, and c are constants specific to each solder material. The feature amount A is a parameter indicating the degree of difference in the infrared absorption of the specific wave number between the solder material to be compared and the solder material to be inspected. Therefore, by obtaining these parameters, the difference in the content of carboxylic acid and carboxylate between the solder material to be compared and the solder material to be inspected can be analyzed, and the viscosity of the solder material to be inspected is inspected. It can be done.

  As the calculation method of the feature amount A, three types shown in the following equations (2) to (4) are conceivable.

A = Achlo / Aacid (2)
A = Achlo / Aref (3)
A = Aref / Aacid (4)
here,
Aacid is an absorbance measurement value near the absorption wavelength of carboxylic acid,
Achlo is the absorbance measurement value near the absorption wavelength of the carboxylate,
Aref is the absorbance measurement value near the reference wavelength,
It is. The reference wavelength indicates a wavelength peak that does not show a change in absorbance due to deterioration of the solder material, and may be any wavelength as long as there is no such change.

  Further, the same solder material is used as the inspection object and the comparison object. Note that “use the same solder material” means a solder material having the same type, and the lot may be different as long as the type is the same. For example, the inspection object is a solder material a of a certain type and a certain lot. In this case, the comparison target is a new solder material b of the same type and different lot as the solder material a, and a solder material b ′ in which the viscosity is changed by using the solder material b in the printing process, or a solder material a. Solder material c ′ having the same type as that of the solder material b and a different lot of solder material c used in the printing process to change the viscosity can be used.

[Example 1]
Next, an example of the solder material inspection method of the present embodiment described above will be described.

  First, a solder material to be inspected in this embodiment will be described. In this example, a solder material containing each substance shown in FIG. 2 as a component was used for the inspection. As shown in the figure, the solder material of this example is 80-90% tin, 1-3% silver, less than 1% copper, 2-4% diethylene glycol monohexyl ether, Contains less than 1% 2-ethyl-1,3-hexanediol and 4-6% rosin.

The main component of the solder material is a metal such as tin (Sn) or lead (Pb). In the solder material of this embodiment, tin is used as the metal as shown in FIG. Further, as the carboxylic acid which is a main component that brings about a reducing power in the solder material, rosin (C ₁₉ H ₂₉ COOH) is used in the solder material of this example as shown in FIG.

  In the present embodiment, the solder material shown in FIG. 2 was used as a comparison target, and the solder material after being used in a printed circuit board printing process was used as an inspection target. Hereinafter, the solder material to be compared may be simply referred to as “comparison object”, and the solder material to be inspected may be simply referred to as “inspection object”.

Here, with respect to the comparative and test object, respectively irradiated with infrared same intensity, it detects the intensity of the band of the ^{500cm -1 ~3000cm} -1 in infrared ray reflected the comparative (Second strength) test It was detected band intensity of ^{500cm -1 ~3000cm} -1 in the infrared ray reflected the target (first intensity) (first detection step, second detection step).

Further, in this example, for each wave number, the infrared absorbance of the comparison target (second infrared absorbance) and the infrared absorbance of the test target (first infrared absorbance) are expressed by the following equations (5) and (6). Calculated. That is, for the absorbance, a blank value (intensity at the wave number h of the irradiated infrared ray) corresponding to the wave number h is BL, an intensity at the wave number h of the infrared ray reflected from the comparison object is A, and the wave number of the infrared ray reflected from the inspection object The intensity at h is B,
Absorbance of infrared rays to be compared (corresponding to wave number h) A ′ = − log (A / BL) (5)
Absorbance of infrared rays to be examined (corresponding to wave number h) B ′ = − log (B / BL) (6)
Can be calculated for each wave number.

  FIG. 3 is a spectrum chart showing the calculated absorbance. In the figure, the horizontal axis represents the wave number of infrared rays (Wave Number), and the vertical axis represents the absorbance of infrared rays. As shown in the figure, it is observed that there is a difference between the absorbance of the infrared ray to be compared and the absorbance of the infrared ray to be inspected.

  FIG. 4 is a chart showing the relationship between the wave number of infrared rays and the absorbance difference corresponding to the wave number. That is, the chart of FIG. 4 shows an absorbance difference obtained by subtracting the absorbance of the comparison object from the absorbance of the examination object shown in the chart of FIG.

4, in the test object and the comparison object, 600 cm around ^-1, 1300 cm around ^-1, 1600 cm around ^-1, the absorbance around ¹⁷⁰⁰ -1 ^{cm -1,} it can be seen that a large difference is.

^{Specifically,} 600 cm ^-1, 1300 cm -1, near 1600 cm ^-1, infrared absorbance of the test object is found to be higher than the infrared absorbance of the comparison object. It can also be seen that the infrared absorbance of the test object is lower than that of the comparison object in the vicinity of 1700 cm ⁻¹ .

Here, in the infrared spectrum chart, it is known that the absorption observed near 600 cm ⁻¹ is due to the vibration of the oxygen-metal bond in the metal oxide. Furthermore, the absorption observed at around 1300 cm ^-1 is due to the symmetric stretching vibration of carboxylic acid salt, the absorption observed at around 1600 cm ^-1 is to be due to the antisymmetric stretching vibration of carboxylate Are known. Furthermore, it is known that the absorption observed in the vicinity of 1700 cm ⁻¹ indicates absorption due to stretching vibration of a double bond in carboxylic acid.

Therefore, in the vicinity of 600 cm ⁻¹ , the infrared light absorbance of the inspection object is higher than that of the comparison object. Therefore, the inspection object contains a larger amount of metal oxide than the comparison object. It can be seen that the degree of oxidation is higher than the target.

Further, in the vicinity of 1300 cm ^-1 and near 1600 cm ^-1, who inspected, than compared, since the infrared-ray absorbance is high, in the test object, contains a large amount carboxylates than comparison It can be seen that the viscosity is higher than the comparison target.

Further, in the vicinity of 1700 cm ⁻¹ , since the infrared light absorbance of the inspection object is lower than that of the comparison object, the inspection object has less carboxylic acid than the comparison object, and the reducing power is lower than that of the comparison object. I can see that it is low

  Thus, in this embodiment, for each wave number of the infrared spectrum, the intensity of the infrared ray that reflects the solder material to be inspected (first intensity) and the intensity of the infrared ray that reflects the solder material to be compared (second intensity) Thus, the infrared absorbance (first infrared absorbance) of the solder material to be inspected and the infrared absorbance (second infrared absorbance) of the solder material to be compared are obtained.

For each wave number of the infrared spectrum, an absorbance difference is obtained by subtracting the absorbance of the solder material to be compared from the absorbance of the solder material to be inspected. ^{Here, 600cm -1, 1300cm -1, 1600cm} -1, referring to the absorbance difference at around 1700 cm ^-1, containing of the metal oxide contained in the test-sample solder material, containing a degree of carboxylic acid, carboxylic The content of acid salt can be ascertained.

  And, from the content of this metal oxide, it is possible to grasp the degree of oxidation of the solder material to be inspected, from the content of carboxylic acid, it is possible to grasp the reducing power of the solder material to be inspected, from the content of carboxylate, The viscosity of the solder material to be inspected can be grasped.

  Next, the difference between the infrared absorbance of the comparison object and the infrared absorbance of the test object was examined. Specifically, the feature amount A is obtained by substituting the absorbances A ′ and B ′ obtained by the above formulas (5) and (6) into any of the above formulas (2) to (4). For example, when the characteristic amount A is obtained using the equation (2), the absorbances A ′ and B ′ are obtained for wave numbers near the absorption wavelength of the carboxylic acid and the absorption wavelength of the carboxylate.

  Here, FIG. 5 is a graph showing the correlation between the feature amount A and the viscosity of the solder material, where the horizontal axis is the feature amount A and the vertical axis is the viscosity. Note that the ◆, ■, and ▲ in FIG. The plot in Fig. 2 illustrates the experimental values when the feature amount A is obtained using equation (2). Each of the ◆, ■, and ▲ plots has different measurement dates and conditions for deterioration. But it shows that the calibration curve works well.

  As is clear from FIG. 5, the feature amount A and the viscosity of the solder material always show a substantially constant correlation. Specifically, a quadratic function curve as shown in the above equation (1) (in the drawing) , Indicated by a solid line).

  For this reason, if the above-mentioned quadratic function curve is a calibration curve equation and the calibration curve equation is specified for the solder material, the characteristic value A is obtained from the measurement result of the infrared absorbance of the inspection object, and this characteristic value A is calculated. By substituting in the calibration curve equation, the viscosity of the solder material to be inspected can be obtained.

  Further, in order to specify the calibration curve equation, the coefficients a to c in the equation (1) are obtained by the following procedure. First, at least three types of solder material samples having different degrees of deterioration are set as comparison targets, and three types of feature amounts A1 to A3 are obtained from the measurement results of these comparison targets. Then, the three calibration curve equations into which the respective feature amounts A1 to A3 are substituted are set as simultaneous equations, and the solutions of a to c may be obtained by solving them.

  Thus, in this embodiment, for each wave number of the infrared spectrum, the intensity of the infrared ray that reflects the solder material to be inspected (first intensity) and the intensity of the infrared ray that reflects the solder material to be compared (second intensity) Thus, the infrared absorbance (first infrared absorbance) of the solder material to be inspected and the infrared absorbance (second infrared absorbance) of the solder material to be compared are obtained.

Then, a plurality of feature amounts A for the solder material are obtained from infrared absorbances (second infrared absorbances) of a plurality of types of solder materials to be compared, and a calibration curve equation for the solder material is specified. ^Here, 1300 cm ^-1, 1600 cm -1, from the absorbance at around 1700 cm ^-1, the correlation relationship between the feature amount A and the viscosity, specifying the calibration curve equation. Also, one of the comparison targets is a new solder material, and the absorbance for this new solder material is the initial absorbance value in equations (2) to (4).

  Then, for each wave number of the infrared spectrum, the inspection target feature amount A is obtained from the absorbance of the solder material to be inspected, and the inspection target viscosity is calculated by substituting the inspection target feature amount A into the calibration curve equation. The

  Next, a new solder material is set as a comparison target, and each of the printing materials printed in the printed circuit board is printed 200 times, 400 times, 600 times, 800 times, 1000 times, and 1200 times. The result analyzed by the method shown in the Example is shown in FIG.

  FIG. 6A shows the relationship between the wave number of infrared rays and the difference in absorbance obtained by subtracting the absorbance of the solder material to be compared from the absorbance of the solder material to be inspected corresponding to each wave number, for each test object. It is a chart. The horizontal axis represents the wave number of infrared rays, and the vertical axis represents the difference in absorbance, which is the difference between the absorbance of the solder material to be inspected and the absorbance of the solder material to be compared.

From FIG. 6 (a), as the print count of the solder material is increased, difference in absorbance near 1300 cm ^-1 and near 1600 cm ^-1 is higher, absorbance difference of around 1700 cm ^-1 is seen to be decreased. Thereby, it can be seen that as the number of times of printing increases, the carboxylic acid in the solder material decreases and the carboxylate salt increases. From the result of the increase in carboxylate, it can be analyzed that the viscosity of the solder material increases as the number of times of printing increases.

Actually, when the viscosity was measured for each inspection object, as shown in FIG. 6B, it was confirmed that the number of times the solder material was printed and the viscosity of the solder material had a positive correlation. Further, the difference in the absorbance of infrared rays in the vicinity of 1600 cm ⁻¹ of the solder material and the viscosity of the solder material have a positive correlation, and the difference in the absorbance of infrared rays in the vicinity of 1700 cm ⁻¹ of the solder material and the viscosity of the solder material have a negative correlation. It was also confirmed that there was a relationship. This relationship is established because as the number of times the solder material is printed increases, the amount of carboxylic acid contained in the solder material decreases and the absorption of infrared rays in the vicinity of 1700 cm ⁻¹ decreases, and is contained in the solder material. This is because the amount of carboxylate increases and the absorption of infrared rays in the vicinity of 1600 cm ⁻¹ increases, and the viscosity increases as the carboxylate increases.

Furthermore, the particular wave number of each the above ^{(1300cm -1, 1600cm -1, 1700cm} -1) is capable of numerical changes. That is, a particular wave ^number, 1300 cm ^-1, 1600 cm -1, is not limited to 1700 cm ^-1, it is possible to set the scope of the particular wave number. This point will be specifically described.

First, as in the analysis in FIG. 6, a new solder material is used as a comparison target, and the number of times of printing in the printing process of the printed board is 200 times, 400 times, 600 times, 800 times, 1000 times, and 1200 times. As a test object, the absorbance difference was determined for each test object by the method shown in this example. The results are shown in FIGS. In FIG ^7, shows the absorbance differences at a wave number band of 1270cm ^-1 ~1430cm -1, ^8, shows the absorbance differences at a wave number band of 1500 cm -1 1650 cm ^-1, 9, shows the absorbance differences at a wave number band of 1665cm ^-1 ~1730cm ^-1.

The absorption peak of the symmetrical stretching vibration of the carboxylate contained in the solder material is detected in the vicinity of 1300 cm ⁻¹ (strictly, 1323 cm ⁻¹ ), but as shown in FIG. 7, the absorption peak is 1270 cm ^{−1 to} 1430 cm ⁻¹ . if interest, it can be distinguished difference in absorbance difference for each inspection ^object, if attention to 1282cm ^-1 ~1382cm -1, can be observed more conspicuously in difference in absorbance difference for each inspection object. ^Therefore, if at least one of wave numbers between 1270cm ^-1 ~1430cm -1 and the noticed wave number, it is possible to analyze the content of the carboxylate of each inspection object.

Further, the absorption peak of the antisymmetric stretching vibration of the carboxylate (strictly, 1590 cm ^-1) 1600 cm near ^-1 are detected, as shown in FIG. ^8, by focusing on the 1500 cm -1 1650 cm ^-1 For example, the difference in absorbance difference for each inspection object can be distinguished. If attention is paid to 1562 cm ^{−1 to} 1624 cm ⁻¹ , the difference in absorbance difference for each inspection object can be observed more remarkably. ^Therefore, if at least one of wave numbers between 1500 cm -1 1650 cm ^-1 and the noticed wave number, it is possible to analyze the content of the carboxylate of each inspection object.

Furthermore, although the absorption peak of the carbon-oxygen double bond of carboxylic acid is detected in the vicinity of 1700 cm ⁻¹ , as shown in FIG. 9, if attention is paid to 1665 cm ^{−1 to} 1730 cm ⁻¹ , the absorbance for each test object. If the difference in the difference can be distinguished and attention is paid to 1683 cm ^{−1 to} 1710 cm ⁻¹ , the difference in absorbance difference for each inspection object can be observed more remarkably. ^Therefore, if the noticed wave number at least one of wave numbers between 1665cm ^-1 ~1730cm -1, it is possible to analyze the content of the carboxylic acid of each inspection target.

[Solder Material Inspection Equipment]
Next, a solder material inspection apparatus that realizes the solder material inspection method of this embodiment will be described. Note that the solder material inspection apparatus described below is merely an example of an apparatus that realizes the solder material inspection method of the present embodiment. In realizing the solder material inspection method of the present embodiment, the following solder material inspection apparatus is used. Is not mandatory.

  As shown in FIG. 1, the solder material inspection apparatus 100 according to the present embodiment includes an infrared spectroscopic measurement unit 10, an input unit 20, a storage unit 30, a calculation unit 40, an output unit 50, and a control unit 60. ing.

  The infrared spectroscopic measurement unit 10 is means for irradiating a solder material as a measurement object with light and detecting the infrared intensity of a specific wave number in the reflected light. The input unit 20 is a means for an operator to input a known viscosity of a solder material. The storage unit 30 is a means for storing a viscosity calculation parameter (for example, a coefficient of a calibration curve equation, a feature amount initial value) used when calculating the viscosity of the solder material. The calculation unit 40 is a unit that calculates the viscosity of the solder material based on the infrared intensity measured by the infrared spectroscopic measurement unit 10 and the viscosity calculation parameter stored in the storage unit 30. The output unit 50 is a unit that outputs the viscosity of the solder material calculated by the calculation unit 40.

  The control unit 60 is a block that processes an analog signal (infrared intensity) sent from the infrared spectroscopic measurement unit 10, an A / D (Analog to Digital) converter that converts the analog signal into a digital signal, And a computer that performs data processing based on a digital signal. Furthermore, the control unit 60 controls each of the above units.

  Here, when calculating the viscosity of the solder material, the characteristic amount A of the solder material is obtained. As described above, the characteristic amount A is obtained from the first intensity, the first infrared absorbance of the specific wave number in the solder material to be inspected, and from the second intensity, the characteristic wave number of the specific wave number in the solder material to be compared. The second infrared absorbance is obtained and calculated from the first infrared absorbance and the second infrared absorbance.

  As a result, the feature amount A indicates the difference between the infrared absorption of the specific wave number of the solder material to be inspected and the infrared absorption of the specific wave number of the solder material to be compared. Here, depending on the content of carboxylic acid and carboxylate in the solder material, the amount of infrared rays absorbed at a specific wave number in the solder material changes, and the intensity of the infrared wave at a specific wave number that reflects the solder material, that is, the solder material Infrared absorbance of the specific wave number changes at, and the feature amount A also changes accordingly.

  Therefore, the operator of the solder material inspection apparatus can know the content of carboxylic acid and carboxylate contained in the solder material to be inspected by referring to the feature amount A. Degradation can be inspected.

  Further, in the above configuration, if an optical filter that transmits only infrared rays is provided between the light source and the solder material or between the solder material and the intensity detection means, the intensity detection means can detect infrared rays reflected from the solder material. Can be detected.

  Examples of the solder material inspection apparatus according to this embodiment will be described below.

[Example 2]
The solder material inspection apparatus 100 according to the present embodiment includes an infrared spectroscopic measurement unit 10 as means for irradiating a solder material as a measurement object with light and detecting infrared intensity of a specific wave number in the reflected light. . First, a configuration example of the infrared spectroscopic measurement unit 10 will be described with reference to FIG.

  As shown in FIG. 10, the infrared spectroscopic measurement unit 10 includes a light source 11, a bandpass filter 12, a plate 13, and a photoelectric converter (intensity detection means) 14. In the infrared spectroscopic measurement unit 10, the solder material 16 serving as a measurement object is placed on the plate 13. The solder material 16 corresponds to the solder material to be compared or inspected, and reflects irradiated infrared rays.

  The light source 11 is a lamp that emits light in the direction of the solder material 16 on the plate 13. For example, a global lamp, a ceramic light source, a xenon lamp, a PbSnTe laser, or the like is used.

  The band pass filter 12 is an optical filter disposed between the solder material 13 on the plate 12 and the photoelectric converter 14. This band pass filter 12 transmits only infrared rays having a specific wave number. The specific wave number is the same as that described in Example 1 above, and is the wave number at which at least one infrared absorption of carboxylic acid and carboxylate salt is observed.

  The photoelectric converter 14 detects the intensity of incident infrared rays. Further, the photoelectric converter 14 generates an analog signal indicating the detected infrared intensity, and transmits the analog signal to the control unit 60. Examples of the photoelectric converter 14 include devices using MCT (photoconductive element, HgCdTe), pyroelectric element, thermopile, etc. (however, a pyroelectric element requires a chopper or a pulsed light source). It is done. The photoelectric converter 14 is provided so as to be positioned on the optical axis of infrared rays reflected from the solder material 16 on the plate 13.

  According to the solder material inspection apparatus 100, the digital signal processed by the computer of the control unit 60 is data indicating the intensity of the infrared of the wave number of interest reflected from the solder material 16.

  Therefore, in the solder material inspection apparatus 100, the intensity of infrared rays reflected from the solder material 16 to be compared is determined by placing the solder material 16 to be compared on the plate 13 and irradiating the solder material 16 with infrared light having a specific wave number. (Second intensity) may be detected by the photoelectric converter 14, and then the solder material 16 to be inspected may be disposed on the plate 13 to detect the intensity of infrared rays (first intensity) in the same manner. As a result, data indicating the intensity of infrared light reflected from the solder material 16 to be compared and data indicating the intensity of infrared light reflected from the solder material 16 to be inspected are sequentially transmitted to the control unit 60. .

  Then, the control unit 60 obtains the infrared absorbance (first infrared absorbance) of the specific wave number in the inspection target and the infrared absorbance (second infrared absorbance) of the specific wave number in the comparison target based on each intensity. Furthermore, the control unit 60 can determine the viscosity of the inspection object based on the absorbance of the infrared wave of interest wave number in the comparison object and the absorbance of the infrared wave of interest wave number in the inspection object or the calibration curve equation.

  Further, as shown in FIG. 1, in the solder material inspection apparatus 100, when the storage unit 30 is connected to the control unit 60, only the intensity of infrared rays that reflect the solder material to be compared is detected in advance. Data indicating the strength can be stored in the storage unit 30. Thus, even when a plurality of solder materials to be inspected are continuously inspected, it is possible to detect the intensity of infrared rays that reflect the solder material to be compared only once.

  The solder material inspection apparatus 100 needs to set initial parameters used for calculating the viscosity of the solder material before actually measuring the viscosity of the solder material. First, the setting sequence will be described with reference to FIG.

  In the sequence at the time of setting shown in FIG. 11, first, for three types of solder material samples (samples 1 to 3) whose viscosity is a known value, the infrared spectroscopic measurement unit 10 measures the absorbance for infrared of a specific wave number. (S1, S3, S5). At this time, the three types of samples are the same type of solder material having different viscosities (different degrees of deterioration), and a new solder material is used for one of the samples. Furthermore, since the viscosities of samples 1 to 3 are known, the viscosities are input through the input unit 20 (S2, S4, S6).

  By substituting the infrared absorptivity measured in steps S1, S3, and S5 into any of the above-described equations (2) to (4), three types of feature amounts A can be obtained. Furthermore, by substituting the characteristic amount A and the viscosity of the solder material input in the steps S2, S4, and S6 into the above-described equation (1), three calibration curve equations can be made simultaneous. The simultaneous equations are solved by the calculation unit 40, whereby the parameters a to c included in the equation (1) are calculated (S7). That is, in S7, the calibration curve equation for the solder materials of Samples 1 to 3 is calculated.

  The parameters a to c of the calibration curve equation calculated in S <b> 7 and the infrared absorption measurement value for the new sample are stored in the storage unit 30 because they are used in the subsequent solder material viscosity measurement process. The above is the setting sequence executed before the actual viscosity measurement of the solder material.

  Next, with respect to the solder material sample whose viscosity is an unknown value, an operation sequence for obtaining the viscosity from the measurement result of the absorbance with respect to the infrared of the specific wave number by the infrared spectroscopic measurement unit 10 will be described with reference to FIG. .

  In the operating sequence shown in FIG. 12, first, the infrared spectroscopic measurement unit 10 measures the absorbance of infrared rays of a specific wave number for a solder material sample (unknown sample) whose viscosity is an unknown value (S11). At this time, for the solder material in the unknown sample, the calibration curve equation is calculated (specified) in the above-described setting sequence.

  The infrared absorbance of the unknown sample measured in S11 is sent to the calculation unit 40, and the calculation unit 40 calculates the viscosity of the unknown sample. That is, from the infrared absorption of the unknown sample and the infrared absorption of the new sample stored in the storage unit 30, the feature quantity A of the unknown sample is calculated using any one of the above-described formulas (2) to (4). The viscosity of the unknown sample is obtained by substituting this characteristic amount A into the specified calibration curve equation (ie, equation (1)) of the parameters a to c (S12).

  The viscosity of the unknown sample obtained in S12 is temporarily stored in the storage unit 30 (S13), and then read out from the storage unit 30 according to an instruction from the control unit 60 (S14) and output in the output unit 50. (S15).

  In the present embodiment, the configuration of the infrared spectroscopic measurement unit 10 is not limited to the example of FIG. 10 described above, and may be configured as shown in FIG.

  In the solder material inspection apparatus 100 of FIG. 13, the plate 13 includes a light-transmitting region (ZnSe or the like) 13a that transmits light between one surface side and the other surface side. And the solder material 16 is arrange | positioned on the translucent area | region 13a of the one surface side in the plate 13. FIG.

  Furthermore, the light source 11, the band pass filter 12, and the photoelectric converter 14 are disposed at a position facing the other surface side of the plate 13, and mirrors 17 and 18 are disposed. Specifically, the mirror 17 is arranged on the optical axis of the light source 11 along the traveling direction of the light from the light source 11. And the mirror 17 is installed so that the light irradiated from the light source 11 may be reflected in the direction of the translucent area | region 13a. Further, the mirror 18 is disposed so as to reflect the light from the translucent region 13 a toward the photoelectric converter 14.

  Also, the solder material inspection apparatus 100 shown in FIGS. 10 and 13 can be modified for in-line analysis by being provided in the vicinity of the printing apparatus 200 for a printed circuit board. That is, the solder material inspection apparatus 100 can be used for in-line analysis of the deterioration degree of the solder material used in the printing process in the production line of the printed circuit board.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the embodiments can be obtained by appropriately combining the respective technical means disclosed in the above-described embodiments. The form is also included in the technical scope of the present invention.

  In the control unit 60 of the above-described embodiment, a calculation unit such as a CPU executes a program stored in a storage unit such as a ROM (Read Only Memory) or a RAM, an input unit such as a keyboard, and an output unit such as a display. Alternatively, it can be realized by controlling communication means such as an interface circuit. Therefore, the computer having these means can realize various functions and various processes of the control unit 60 simply by reading the recording medium storing the program and executing the program. In addition, by recording the program on a removable recording medium, the various functions and various processes described above can be realized on an arbitrary computer.

  As the recording medium, a memory (not shown) such as a ROM may be used as a program medium for processing by the microcomputer, and a program reader is provided as an external storage device (not shown). It may be a program medium that can be read by inserting a recording medium therein.

  In any case, the stored program is preferably configured to be accessed and executed by the microprocessor. Furthermore, it is preferable that the program is read out, and the read program is downloaded to a program storage area of the microcomputer and the program is executed. It is assumed that this download program is stored in advance in the main unit.

  The program medium is a recording medium configured to be separable from the main body, such as a tape system such as a magnetic tape or a cassette tape, a magnetic disk such as a flexible disk or a hard disk, or a disk such as a CD / MO / MD / DVD. Fixed disk system, card system such as IC card (including memory card), or semiconductor memory such as mask ROM, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), flash ROM, etc. In particular, there are recording media that carry programs.

  In addition, if the system configuration is capable of connecting to a communication network including the Internet, the recording medium is preferably a recording medium that fluidly carries the program so as to download the program from the communication network.

  Further, when the program is downloaded from the communication network as described above, it is preferable that the download program is stored in the main device in advance or installed from another recording medium.

  The solder material inspection method and the solder material inspection apparatus of the present invention are suitable as a method and apparatus for inspecting a paste-like solder material used in a printing process in a printed circuit board production line. The present invention is not limited and can be widely applied to all known solder materials.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention and is a block diagram illustrating a configuration of a main part of a solder material inspection apparatus. It is a table | surface which shows the content rate (weight%) of the content of a solder material of the test object in the solder material test | inspection method of one Example of this invention, and each component. It is the chart obtained by the solder material test | inspection method of one Example of this invention, Comprising: It is a spectrum chart which shows the infrared light absorbency of the solder material of test object, and the infrared light absorbency of the solder material of a comparison object. It is a chart which shows the light absorbency difference obtained by subtracting the infrared light absorbency of the solder material of a comparison object from the infrared light absorbency of the solder material of a test object shown in FIG. It is a graph which shows the correlation with the feature-value A and the viscosity of a solder material. (A) is a chart showing, for each inspection object, a difference in absorbance obtained by subtracting the infrared absorbance of the solder material for comparison from the infrared absorbance of the solder material for each inspection object for a plurality of inspection objects, (b) ) Is a table showing the number of times of printing, viscosity, and absorbance of infrared rays of a predetermined wave number for a plurality of inspection objects. The plurality of inspection object, a chart showing the absorbance difference obtained by subtracting the infrared absorbance of the comparative-sample solder material from an infrared absorbance of the solder material of the inspection object for each inspection target, 1270cm ^-1 ~1420cm ^-1 It is a chart about the wave number band of. The plurality of inspection object, a chart showing the absorbance difference obtained by subtracting the infrared absorbance of the comparative-sample solder material from an infrared absorbance of the solder material of the inspection object for each inspection target, 1500 cm ^-1 1650 cm ^-1 It is a chart about the wave number band of. The plurality of inspection object, a chart showing the absorbance difference obtained by subtracting the infrared absorbance of the comparative-sample solder material from an infrared absorbance of the solder material of the inspection object for each inspection target, 1665cm ^-1 ~1725cm ^-1 It is a chart about the wave number band of. 1 is a schematic diagram illustrating a solder material inspection apparatus that realizes a solder material inspection method according to an embodiment of the present invention. It is a timing chart which shows the sequence at the time of the setting by the said solder material test | inspection apparatus. It is a timing chart which shows the sequence at the time of the operation | movement by the said solder material test | inspection apparatus. It is a schematic diagram which shows the modification of the solder material test | inspection apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Light source 12 Band pass filter 13 Plate 13a Translucent area | region 14 Photoelectric converter (intensity detection means)
16 Solder material 20 Input unit 30 Storage unit 40 Calculation unit 50 Output unit 60 Control unit (control means)
100 Solder material inspection equipment

Claims (15)

A detection step of detecting a first intensity of infrared of a specific wave number reflected from the solder material to be inspected by irradiating light to the solder material to be inspected;
Based on the detected first strength, an inspection process for inspecting the viscosity of the solder material to be inspected,
A solder material inspection method comprising: A first detection step of detecting a first intensity of infrared of a specific wave number reflected from the solder material to be inspected by irradiating light to the solder material to be inspected;
A second detection step of detecting the second intensity of the infrared of the specific wave number reflected from the solder material to be compared by irradiating the solder material to be compared with the light;
Based on the detected first and second strengths, an inspection process for inspecting the viscosity of the solder material to be inspected,
A solder material inspection method comprising: In the above inspection process,
Based on the first intensity, obtain the first infrared absorbance of the specific wave number in the solder material to be inspected,
Based on the second intensity, to determine the second infrared absorbance of the specific wave number in the solder material for comparison,
3. The solder material according to claim 2 , wherein the viscosity of the solder material to be inspected is calculated by substituting the first infrared absorbance into a calibration curve equation specified based on the second infrared absorbance. Inspection method. The specific wave ^number, a solder material test method according to any one of claims 1 to 3, characterized in that the wave number included in a range of 1270cm ^-1 ~1430cm -1. The specific wave ^number, a solder material test method according to any one of claims 1 to 3, characterized in that the wave number included in a range of 1500 cm -1 1650 cm ^-1. The specific wave ^number, a solder material test method according to any one of claims 1 to 3, characterized in that the wave number included in a range of 1665cm ^-1 ~1730cm -1. The specific wave number, a solder material test method according to any one of claims 1 to 3, characterized in that the salt contained in the solder material is a wave number included in a wave number band of infrared absorbing. The specific wave number, a solder material test method according to any one of claims 1 to 3, characterized in that the acid contained in the solder material is a wave number included in a wave number band of infrared absorbing. The solder material inspection method according to claim 7 , wherein the salt is a carboxylate. 9. The solder material inspection method according to claim 8 , wherein the acid is a carboxylic acid. A light source that emits light to the solder material to be inspected and the solder material to be compared;
  Intensity detecting means for detecting a first intensity of infrared of a specific wave number reflected from the solder material to be inspected by being irradiated with the light;
  Storage means for storing the second intensity of the infrared of the specific wave number reflected from the solder material to be compared when light is applied to the solder material to be compared;
  Control means for outputting the viscosity of the solder material to be inspected based on the first intensity detected by the intensity detection means and the second intensity stored in the storage means;
A solder material inspection apparatus comprising: A light source that emits light to the solder material to be inspected and the solder material to be compared;
The first intensity of the infrared of a specific wave number reflected from the solder material to be inspected is detected by the light irradiation, and the infrared wave of the specific wave number reflected from the solder material to be compared by being irradiated with the light. Intensity detecting means for detecting the second intensity;
Control means for outputting the viscosity of the solder material to be inspected based on the detected first and second strengths,
A solder material inspection apparatus comprising: The control means includes
Based on the first intensity, obtain the first infrared absorbance of the specific wave number in the solder material to be inspected,
Based on the second intensity, to determine the second infrared absorbance of the specific wave number in the solder material for comparison,
The solder material according to claim 12 , wherein the viscosity of the solder material to be inspected is calculated by substituting the first infrared absorbance into a calibration curve equation specified based on the second infrared absorbance. Inspection device. A control program for a solder material inspection apparatus, which realizes the function of the control means according to claims 11 and 12 by a computer. A computer-readable recording medium storing the control program according to claim 14 .

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