KR20220044667A - Solder paste - Google Patents

Abstract

An objective of the present invention is to provide solder paste which can suppress a viscosity increase when solder paste ages, realize solder attachment with few voids, and suppress soft errors. The solder paste has an alloy composition consisting of less than 5 mass ppb of U, less than 5 mass ppb of Th, less than 5 mass ppm of Pb, less than 5 mass ppm of As, 0-600 mass ppm of Ni, 0-100 mass ppm of Fe, and the remainder consisting of Sn, satisfies the following formula (1), and comprises solder powder made of a solder alloy with α-rays lower than or equal to 0.02cph/cm^2 and flux including hydro-rosin acid methyl, N,N,N',N'-tetrakise (2-hydroxypropyl) ethylene diamine, and a solvent. 20≤Ni+Fe≤700 (1) In formula (1), Ni and Fe represent the content (mass ppm) in the alloy composition.

Description

Solder paste {SOLDER PASTE}

The present invention relates to a solder paste.

As the brazing material, a solder paste containing brazing powder and flux is used.

In electronic components mounted on printed circuit boards, miniaturization and high performance are further demanded. As such an electronic component, a semiconductor package is mentioned, for example. In a semiconductor package, the semiconductor element which has an electrode is sealed with the resin component. A solder bump made of a solder material is formed on this electrode. With this soldering material, the semiconductor element and the printed circuit board are soldered together, and both are connected.

For soldering materials, the influence of α-rays on soft errors becomes a problem. In order to reduce such a bad influence on the operation|movement of a semiconductor element, development of the low alpha dose material containing a soldering material is being carried out.

A factor serving as an α-ray source is, for example, a trace amount of radioactive element contained in a brazing alloy in a brazing material, particularly a tin (Sn) metal serving as a base. A braze alloy can be manufactured by melt-mixing a raw material metal. In such a braze alloy, for the design of a low α-dose material, it becomes important to remove the upstream radioactive elements such as uranium (U), thorium (Th), and polonium (Po) from the alloy composition.

On the other hand, it is not technically difficult to remove U, Th, and Po in the refining of Sn metal (for example, refer patent document 1).

In general, Sn contains lead (Pb) and bismuth (Bi) as impurities. In Pb and Bi, ²¹⁰ Pb and ²¹⁰ Bi, which are radioactive isotopes, decay by β to become ²¹⁰ Po, and when ²¹⁰ Po decays to α to generate ²⁰⁶ Pb, α-rays are generated. It is said that this series of aberrations in the uranium series is the main cause of the generation of α-rays from the brazing material.

In addition, in the evaluation of the amount of α radiation generated from a material, “cph/cm ² ” is often used as a unit. "cph/cm ² " is an abbreviation of "counts per hour/cm ² ", and means the number of counts of α-rays per 1 cm ² per hour.

About the half-life of Pb and Bi, it is as follows.

For Bi, the half-life of ²¹⁰ Bi is about 5 days. For Pb, the half-life of ²¹⁰ Pb is about 22.3 years. And it is considered that these influence degrees (absence ratio) can be expressed by the following formula (refer nonpatent literature 1). That is, the influence of Bi on the generation of α-rays is very low compared to that of Pb.

[ ²¹⁰ Bi]≒[ ²¹⁰ Pb]/1.6×10 ³

In the formula, [ ²¹⁰ Bi] represents the molar concentration of ²¹⁰ Bi. [ ²¹⁰ Pb] represents the molar concentration of ²¹⁰ Pb.

As described above, conventionally, in the design of a low α-dose material, it is common to remove U and Th and further thoroughly remove Pb.

In addition, it is known that the α-ray dose generated from the brazing material basically increases with the lapse of time. It is said that this is caused by β decay of radioactive Pb and radioactive Bi in the braze alloy to increase the amount of Po, and α decay of Po to generate α rays. In the case of extremely low α-dose materials, these radioactive elements are hardly contained, but segregation of ²¹⁰ Po is the cause, and the α-ray dose may increase with the passage of time. Although ²¹⁰ Po originally radiates α-rays, since it segregates in the central portion of the braze alloy during solidification of the braze alloy, the radiated α-rays are shielded by the braze alloy. And ²¹⁰ Po is uniformly dispersed in the alloy with the lapse of time, and since it comes to exist also on the surface where an alpha ray is detected, the amount of alpha rays increases with time-dependent change (refer nonpatent literature 2).

As described above, under the influence of trace amounts of impurities contained in the braze alloy, the amount of α radiation generated increases. For this reason, with respect to the design of a low-alpha-dose material, it becomes difficult to add various elements simply like the conventional manufacturing method of a braze alloy.

For example, the method of adding arsenic (As) to a braze alloy is known for the thickening suppression which suppresses the viscosity increase with time-lapse|temporality of a solder paste (for example, refer patent document 2).

On the other hand, the flux used for brazing has the effect of chemically removing metal oxides present on the metal surface of the joining object to be brazed and brazed, thereby enabling the movement of metal elements at the boundary between the two. For this reason, by performing solder bonding using a flux, it becomes possible to form an intermetallic compound between the solder and the metal surface of the object to be joined, and a strong bonding can be obtained.

[Patent Document 1] Japanese Patent Laid-Open No. 2010-156052 [Patent Document 2] Japanese Patent Laid-Open No. 2015-98052

[Non-Patent Document 1] Radioactive Nuclei Induced Soft Errors at Ground Level; IEEE TRANSACTIONS ON NUCLEAR SCIENCE, DECEMBER 2009, VOL. 56, NO. 6, p. 3437-3441 [Non-Patent Document 2] Energy Dependent Efficiency in Low Background Alpha Measurements and Impacts on Accurate Alpha Characterization; IEEE TRANSACTIONS ON NUCLEAR SCIENCE, DECEMBER 2015, VOL. 62, NO. 6, p. 3034-3039

For example, as in the method described in Patent Document 2, in the method of adding As to the braze alloy for suppression of thickening over time of the solder paste, the radioisotope contained in As is added to the alloy by the addition of As. It also contains impurities. In this case, the presence of a radioactive element in the impurity increases the amount of α radiation generated from the brazing material.

Moreover, in soldering by a reflow method, a flux component volatilizes or decomposes|disassembles by heating and gasifies during paste reflow. In addition, there is a problem that voids due to this gasified flux component are generated in the soldered portion.

The present invention has been made in view of the above circumstances, and is a solder paste capable of suppressing an increase in the viscosity of the solder paste over time, realizing soldering with little occurrence of voids, and suppressing the occurrence of soft errors. aims to provide

The present inventors studied for the purpose of designing a brazing alloy with a low α-dose that can suppress the thickening of the solder paste over time without adding As accompanied by impurities containing radioactive elements. According to these studies, Sn as a main component and an alloy containing a predetermined amount of Ni having a melting point of 1455° C. and Fe of 1538° C. By setting it as a composition, it discovered that the thickening suppression in time-lapse|temporality of a solder paste became possible.

In addition, with respect to the problem of voids occurring in the soldering part, by using a specific rosin and an amine in combination, the melt viscosity of the solder paste decreases, and the gasified flux component easily escapes from the inside of the paste. Further discovery of those capable of suppressing generation was accomplished, thereby completing the present invention.

That is, in order to solve the said subject, this invention employ|adopts the following means.

One aspect of the present invention is a solder paste comprising solder powder and a flux, wherein the solder powder comprises: U: less than 5 mass ppb, Th: less than 5 mass ppb, Pb: less than 5 mass ppm, As: less than 5 mass ppm; Ni: 0 mass ppm or more and 600 mass ppm or less, and Fe: 0 mass ppm or more and 100 mass ppm or less, and the balance has an alloy composition composed of Sn, the following formula (1) is satisfied, and the α dose is 0.02 cph/ cm ² or less, and the flux comprises hydrogenated methyl rosinate, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, and a solvent. , is a solder paste.

20≤Ni+Fe≤700 (One)

(1) In the formula, Ni and Fe each represent content (mass ppm) in the alloy composition.

ADVANTAGE OF THE INVENTION According to this invention, the solder paste which suppresses the viscosity increase with time of a solder paste, can implement|achieve soldering with little generation|occurrence|production of a void, and can suppress generation|occurrence|production of a soft error can be provided.

The present invention will be described in detail below.

In this specification, "ppb" regarding a braze alloy composition is "mass ppb" unless otherwise specified. "ppm" is "mass ppm" unless otherwise specified. "%" is "mass %" unless otherwise specified.

(solder paste)

The solder paste of this embodiment consists of a specific soldering powder and a specific flux.

The brazing powder includes: U: less than 5 mass ppb, Th: less than 5 mass ppb, Pb: less than 5 mass ppm, As: less than 5 mass ppm, Ni: 0 mass ppm or more and 600 mass ppm or less, and Fe: 0 mass ppm It consists of a braze alloy whose α-ray amount is 0.02 cph/cm ² or less, having an alloy composition of 100 mass ppm or less and the balance consisting of Sn, satisfying the following formula (1).

20≤Ni+Fe≤700 (One)

(1) In the formula, Ni and Fe each represent content (mass ppm) in the alloy composition. The flux contains hydrogenated methyl rosinate, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, and a solvent.

<Solder Powder>

The solder powder used for the solder paste of this embodiment is U: less than 5 mass ppb, Th: less than 5 mass ppb, Pb: less than 5 mass ppm, As: less than 5 mass ppm, Ni: 0 mass ppm or more and 600 mass ppm and Fe: 0 mass ppm or more and 100 mass ppm or less, and the remainder has an alloy composition composed of Sn, satisfies the following formula (1), and consists of a braze alloy having an α dose of 0.02 cph/cm ² or less.

20≤Ni+Fe≤700 (One)

(1) In the formula, Ni and Fe each represent content (mass ppm) in the alloy composition.

The braze alloy in the present embodiment has U: less than 5 mass ppb, Th: less than 5 mass ppb, Pb: less than 5 mass ppm, As: less than 5 mass ppm, Ni: 0 mass ppm or more and 600 mass ppm or less, and Fe: It has an alloy composition in which 0 mass ppm or more and 100 mass ppm or less, and remainder consists of Sn, said (1) Formula is satisfy|filled.

«U: less than 5 mass ppb, Th: less than 5 mass ppb»

U and Th are radioactive elements. In order to suppress generation|occurrence|production of a soft error, it is necessary to suppress these content in a braze alloy.

In the present embodiment, the contents of U and Th in the braze alloy are each 5 with respect to the total mass (100 mass%) of the braze alloy from the viewpoint of making the α dose generated from the braze alloy 0.02 cph/cm ² or less. less than ppb. From the viewpoint of suppressing the occurrence of soft errors in high-density packaging, the contents of U and Th are preferably 2 ppb or less, respectively, and the lower the better.

«Pb: less than 5 mass ppm»

Generally, Sn contains Pb as an impurity. The radioisotope in this Pb decays β to become ²¹⁰ Po, and ²¹⁰ Po decays to α to generate α ray when ²⁰⁶ Pb is produced. From this, it is preferable that the content of Pb as an impurity in the braze alloy is also as small as possible.

In the present embodiment, the content of Pb in the braze alloy is less than 5 ppm, preferably less than 2 ppm, and more preferably less than 1 ppm with respect to the total mass (100 mass%) of the braze alloy. In addition, 0 ppm or more may be sufficient as the minimum of content of Pb in a braze alloy.

«As: less than 5 mass ppm»

Addition of As to the braze alloy is effective for suppressing the thickening of the solder paste over time, but with the addition of As, the alloy also contains radioactive elements from As-derived impurities, and α dose generated from the brazing material. this increases

In this embodiment, it aims at aiming at the thickening suppression over time of a solder paste, without adding As accompanying the impurity containing a radioactive element.

In the present embodiment, the content of As in the braze alloy is less than 5 ppm, preferably less than 2 ppm, and more preferably less than 1 ppm with respect to the total mass (100 mass%) of the braze alloy. In addition, 0 ppm or more may be sufficient as the minimum of content of As in a braze alloy.

≪Ni: 0 mass ppm or more and 600 mass ppm or less, Fe: 0 mass ppm or more and 100 mass ppm or less, (1) formula≫

Due to brazing adhesion, formation of a Sn-containing intermetallic compound (an intermetallic compound containing Sn) in the vicinity of the joint interface in the braze alloy proceeds, and when this Sn-containing intermetallic compound precipitates, the mechanical strength of the braze joint is reduced. deteriorate

Ni: 0 mass ppm or more and 600 mass ppm or less

Ni is an element that suppresses the formation of the Sn-containing intermetallic compound at the bonding interface.

When the braze alloy contains Ni, the formation of the Sn-containing intermetallic compound is suppressed, and the mechanical strength of the braze joint is maintained. On the other hand, when the content of Ni in the braze alloy exceeds 600 ppm, in the vicinity of the bonding interface in the braze alloy, a SnNi compound precipitates, and there is a fear that the mechanical strength of the braze joint is deteriorated.

In the present embodiment, the content of Ni in the braze alloy is 0 ppm or more and 600 ppm or less, preferably 20 ppm or more and 600 ppm or less, more preferably with respect to the total mass (100 mass%) of the braze alloy. 40 ppm or more and 600 ppm or less.

Fe: 0 mass ppm or more and 100 mass ppm or less

Fe is an element which suppresses formation of a Sn-containing intermetallic compound at a bonding interface similarly to Ni. In addition, within the range of the predetermined content, precipitation of needle crystals by the SnFe compound is suppressed, and short circuit of the circuit can be prevented.

The "acicular crystal" as used herein refers to a crystal having an aspect ratio of 2 or more, which is a ratio of a major axis to a minor axis, in a crystal derived from one SnFe compound.

In the present embodiment, the content of Fe in the braze alloy is 0 ppm or more and 100 ppm or less, preferably 20 ppm or more and 100 ppm or less, more preferably with respect to the total mass (100 mass%) of the braze alloy. 40 ppm or more and 80 ppm or less.

Regarding the braze alloy in the present embodiment, the following formula (1) is satisfied with respect to the alloy composition.

20≤Ni+Fe≤700 (One)

(1) In the formula, Ni and Fe each represent content (mass ppm) in the alloy composition.

(1) Both Ni and Fe in the formula are elements that suppress formation of the Sn-containing intermetallic compound at the bonding interface. In addition, in this embodiment, both Ni and Fe contribute also to the effect of the thickening suppression in time-lapse|temporality of a solder paste.

In order to obtain the effect of suppressing the formation of the Sn-containing intermetallic compound and the effect of suppressing the thickening of the solder paste over time, the total content of Ni and Fe in the braze alloy is determined by the total mass of the braze alloy (100 mass%) , it is necessary to be 20 ppm or more and 700 ppm or less. Content of the sum total of Ni and Fe becomes like this. Preferably they are 40 ppm or more and 700 ppm or less, More preferably, they are 40 ppm or more and 600 ppm or less, Most preferably, they are 40 ppm or more and 200 ppm or less.

However, the above "content of the total of Ni and Fe" becomes the content of Fe when the content of Ni in the braze alloy is 0 ppm, and becomes the content of Ni when the content of Fe in the braze alloy is 0 ppm, When Ni and Fe are coexisted, it becomes content of these sum total.

Moreover, in this embodiment, when Ni and Fe are used together, the ratio of Ni and Fe in a braze alloy is a mass ratio represented by Ni/Fe, Preferably it is 0.4 or more and 30 or less, More preferably, it is 0.4 or more and 10 or less. and more preferably 0.4 or more and 5 or less, and particularly preferably 0.4 or more and 2 or less.

If Ni/Fe of such a mass ratio is in the said preferable range, the effect of this invention will become easier to be acquired.

≪Random Element≫

The alloy composition regarding the braze alloy in this embodiment may contain elements other than the element mentioned above as needed.

For example, regarding the braze alloy in the present embodiment, the alloy composition is, in addition to the elements described above, Ag: 0 mass% or more and 4 mass% or less, and Cu: 0 mass% or more and 0.9 mass% or less You may contain at least 1 sort(s) of.

Ag: 0 mass% or more and 4 mass% or less

Ag is an optional element capable of improving the reliability of the braze alloy by forming Ag ₃ Sn at the crystal interface. Moreover, Ag is an element whose ionization tendency is noble compared with Sn, and by coexisting with Ni and Fe, the thickening inhibitory effect in time-lapse|temporality of a solder paste is improved. In addition, if the content of Ag in the braze alloy is within the above range, the increase in the melting point of the alloy can be suppressed, so that it is not necessary to excessively increase the reflow temperature.

In the present embodiment, the content of Ag in the braze alloy is preferably 0% or more and 4% or less, more preferably 0.5% or more and 3.5% or less, with respect to the total mass (100 mass%) of the braze alloy, and further Preferably they are 1.0 % or more and 3.0 % or less, Especially preferably, they are 2.0 % or more and 3.0 % or less.

Cu: 0 mass% or more and 0.9 mass% or less

Cu is used in a general braze alloy and is an arbitrary element capable of improving the joint strength of a braze joint. Moreover, Cu is an element whose ionization tendency is rare compared with Sn, and by coexisting with Ni and Fe, the thickening inhibitory effect in time-lapse|temporality of a solder paste is improved.

In the present embodiment, the content of Cu in the braze alloy is preferably 0% or more and 0.9% or less, more preferably 0.1% or more and 0.8% or less, with respect to the total mass (100 mass%) of the braze alloy, and further Preferably it is 0.2 % or more and 0.7 % or less.

When using Cu and Ni together in this embodiment, the ratio of Cu and Ni in a braze alloy is a mass ratio represented by Cu/Ni, Preferably it is 8 or more and 175 or less, More preferably, it is 10 or more and 150 or less.

When Cu/Ni of such a mass ratio is in the said preferable range, the effect of this invention will become easier to acquire.

In this embodiment, when Cu and Fe are used together, the ratio of Cu and Fe in a braze alloy is a mass ratio represented by Cu/Fe, Preferably it is 50 or more and 350 or less, More preferably, it is 70 or more and 250 or less.

When Cu/Fe of such a mass ratio is in the said preferable range, the effect of this invention will become easier to be acquired.

In this embodiment, when Cu, Ni, and Fe are used together, the ratio of Cu, Ni, and Fe in the braze alloy is a mass ratio expressed by Cu/(Ni+Fe), preferably 7 or more and 350 or less, more preferably Usually 10 or more and 250 or less.

If Cu/(Ni+Fe) of this mass ratio is the said preferable range, the effect of this invention will become easier to acquire.

For example, regarding the braze alloy in the present embodiment, the alloy composition is, in addition to the elements described above, Bi: 0 mass% or more and 0.3 mass% or less, and Sb: 0 mass% or more and 0.9 mass% or less You may contain at least 1 sort(s) of.

Bi: 0 mass% or more and 0.3 mass% or less

Bi is an element that has low reactivity with flux and exhibits the effect of suppressing the thickening of the solder paste over time. Moreover, Bi is an element which can suppress deterioration of wettability in order to reduce the viscosity of a molten braze while lowering|hanging the liquidus temperature of a brazing alloy.

In the present embodiment, the content of Bi in the braze alloy is preferably 0% or more and 0.3% or less, more preferably 0.0020% or more and 0.3% or less, with respect to the total mass (100 mass%) of the braze alloy, and further Preferably it is 0.01% or more and 0.1% or less, Most preferably, it is 0.01% or more and 0.05% or less.

Sb: 0 mass% or more and 0.9 mass% or less

Sb, like Bi, has low reactivity with a flux, and is an element showing the effect of suppressing the thickening of the solder paste over time. Since wettability deteriorates when there is too much content of Sb in a braze alloy, when adding Sb, it is necessary to set it as an appropriate content.

In the present embodiment, the content of Sb in the braze alloy is preferably 0% or more and 0.9% or less, more preferably 0.0020% or more and 0.9% or less, with respect to the total mass (100 mass%) of the braze alloy, and further Preferably it is 0.01% or more and 0.1% or less, Most preferably, it is 0.01% or more and 0.05% or less.

Regarding the braze alloy in the present embodiment, when the alloy composition further contains at least one of Bi: 0 mass% or more and 0.3 mass% or less, and Sb: 0 mass% or more and 0.9 mass% or less, the above It is preferable that an alloy composition satisfy|fills following (2) Formula.

0.03≤Bi+Sb≤1.2 (2)

(2) In the formula, Bi and Sb each represent content (mass %) in the alloy composition.

(2) Bi and Sb in Formula are both elements which show the thickening inhibitory effect in the time-lapse|temporality of a solder paste. In addition, in this embodiment, both Bi and Sb contribute also to the wettability of a braze alloy.

The total content of Bi and Sb in the braze alloy is preferably 0.03% or more and 1.2% or less, more preferably 0.03% or more and 0.9% or less, with respect to the total mass (100 mass%) of the braze alloy, further preferably is 0.3% or more and 0.9% or less.

However, the above "content of the total of Bi and Sb" becomes the content of Sb when the content of Bi in the braze alloy is 0%, and becomes the content of Bi when the content of Sb in the braze alloy is 0%, When Bi and Sb are used together, it becomes content of these sum total.

In the case of using Bi and Sb together in the present embodiment, the ratio of Bi and Sb in the braze alloy is a mass ratio expressed by Sb/Bi, preferably 0.01 or more and 10 or less, and more preferably 0.1 or more and 5 or less.

If Sb/Bi of such a mass ratio is the said preferable range, the effect of this invention will be acquired more easily.

≪Balance: Sn≫

Regarding the braze alloy in the present embodiment, the remainder of the alloy composition consists of Sn. In addition to the above elements, unavoidable impurities may be contained. Even if it contains an unavoidable impurity, it does not affect the above-mentioned effect.

≪α dose≫

The braze alloy in the present embodiment has an α dose of 0.02 cph/cm ² or less.

This is an α dose to a degree that soft errors do not become a problem in high-density packaging of electronic components.

The α dose generated from the braze alloy in this embodiment is preferably 0.01 cph/cm ² or less, more preferably 0.002 cph/cm ² or less, from the viewpoint of suppressing a soft error in further high-density mounting. , more preferably 0.001 cph/cm ² or less.

The α dose generated from the braze alloy can be measured as follows. This α-dose measurement method is based on the international standard JEDEC STANDARD.

Procedure (i):

A gas flow type α dose measuring device is used.

As a measurement sample, a braze alloy sheet formed by melting a braze alloy and forming a sheet having an area of 900 cm ² on one surface is used.

The braze alloy sheet is installed as a measurement sample in the α dose measuring device, and PR gas is purged there.

In addition, as PR gas, what complies with the international standard JEDEC STANDARD is used. That is, in the PR gas used for the measurement, it is assumed that the impurity radon (Rn) in the gas has decayed for 3 weeks or more after filling the gas cylinder with a mixed gas of 90% argon and 10% methane.

Procedure (ii):

After allowing the PR gas to flow for 12 hours in the α-dose measuring device in which the braze alloy sheet is installed, the α-dose measurement is performed for 72 hours.

Procedure (iii):

The average α dose is calculated as “cph/cm ² ”. An outlier (such as a count due to vibration of the device) removes the count for that hour.

The braze alloy in this embodiment has an α dose of 0.02 cph after heat treatment at 100° C. for 1 hour with respect to the braze alloy sheet when it is molded into a sheet having an area of 900 cm ² on one surface. It is preferably /cm ² or less, more preferably 0.01 cph/cm ² or less, still more preferably 0.002 cph/cm ² or less, particularly preferably 0.001 cph/cm ² or less will be.

A braze alloy exhibiting such an α dose is useful because segregation of ²¹⁰ Po is unlikely to occur in the alloy, and the influence of the α dose with time change is small. By applying a solder alloy exhibiting such an α dose, the occurrence of soft errors is further suppressed, and stable operation of the semiconductor element is further easily ensured.

[Method for producing solder alloy]

The braze alloy in this embodiment can be manufactured by using the manufacturing method which has the process of melt-mixing the raw material metal containing at least 1 type of Ni and Fe, and Sn, for example.

Since the purpose of designing a low-α-dose braze alloy is to use a low-α-dose material as the raw material metal, for example, Sn, Ni and Fe as the raw material metal are each of high purity; and U, Th and Pb are removed. As Sn as a raw material metal, what was manufactured according to the manufacturing method of Unexamined-Japanese-Patent No. 2010-156052 (patent document 1) can be used, for example.

As Ni and Fe as the raw material metals, for example, those manufactured according to Japanese Patent No. 5692467 can be used.

A conventionally well-known method can be used for operation of melt-mixing a raw material metal.

The production of braze powder in this embodiment is known in the art, such as a dropping method in which a molten braze alloy is added dropwise to obtain particles, a centrifugal spraying spraying method, atomization method, submerged granulation method, and a method of pulverizing a bulk braze alloy. method can be employed. In the dropping method or the spraying method, it is preferable to perform dripping or spraying in an inert atmosphere or a solvent in order to make it into a particulate form.

It is preferable that the brazing powder in this embodiment is a spherical powder. Because it is a spherical powder, the fluidity|liquidity of a braze alloy improves.

When the solder powder in this embodiment is a spherical powder, it is preferable to satisfy|fill the symbols 1-8 in the classification of the powder size in JIS Z 3284-1:2014 (Table 2), and it is a symbol 4 - It is more preferable that 8 is satisfied. When the particle size of the solder powder satisfies this condition, the surface area of the powder is not too large, and the increase in the viscosity of the solder paste over time is suppressed, and the aggregation of the fine powder is suppressed, and the increase in the viscosity of the solder paste is suppressed. there is something to be For this reason, soldering to a finer component becomes possible.

In addition, as the braze powder in this embodiment, it is preferable to use what consists of a braze alloy particle group with an average particle diameter of 0.1-50 micrometers, and it is more preferable to use what consists of a braze alloy particle group with an average particle diameter of 1-25 micrometers. It is preferable, and it is more preferable to use what consists of a braze alloy particle group with an average particle diameter of 1-15 micrometers.

If the particle size of the solder powder is within the above preferred range, the increase in the viscosity of the solder paste over time is easily suppressed.

The average particle diameter of the brazing powder here means the particle diameter at 50% of the integrated value in the particle size distribution measured by the laser diffraction scattering type particle size distribution analyzer.

Moreover, it is preferable that the braze powder in this embodiment shares two or more types of braze alloy particle groups from which a particle size distribution differs. Thereby, the slidability of a solder paste can be improved, and workability|operativity, such as becoming easy to print, improves.

For example, as braze powder, sharing two or more kinds of braze alloy grain groups having different average grain diameters is mentioned. As an example, the braze powder which shared the braze alloy particle group (S1) with an average particle diameter of 5 micrometers or more and less than 10 micrometers and the braze alloy particle group S2 with an average particle diameter of 1 micrometer or more and less than 5 micrometers is mentioned preferably.

The mixing ratio of the braze alloy particle group (S1) and the braze alloy particle group (S2) is a mass ratio represented by (S1)/(S2), preferably (S1)/(S2) = 9/1 to 1/9, , 9/1 to 3/7 are more preferable, and 9/1 to 5/5 are still more preferable.

With respect to the brazing powder in the present embodiment, the sphericity of the spherical powder is preferably 0.8 or more, more preferably 0.9 or more, still more preferably 0.95 or more, and particularly preferably 0.99 or more.

The "sphericity of spherical powder" referred to herein can be measured using a CNC image measuring system (Ultra Quick Vision ULTRA QV350-PRO measuring device manufactured by Mitsutoyo Corporation) using the minimum region centering method (MZC method).

Sphericity represents a difference from a true sphere, and is, for example, an arithmetic average value calculated when the diameter of each of 500 braze alloy particles is divided by the major axis, and the closer the value is to the upper limit of 1.00, the closer to a true sphere.

<Flux>

The flux used for the solder paste of this embodiment contains hydrogenated methyl rosinate, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, and a solvent.

≪Hydrogenated methyl rosinate≫

The flux in the present embodiment contains hydrogenated methyl rosinate.

This hydrogenated methyl rosinate is an ester obtainable from a hydrogenated cyclic fatty acid obtainable from rosin and methyl alcohol, and has a CAS number: 8050-15-5 as an alias of hydrogenated methyl abiethate.

The content of hydrogenated methyl rosinate in the flux is preferably 5 mass% or more and 20 mass% or less, more preferably 5 mass% or more and 15 mass% or less, with respect to the total amount (100 mass%) of the flux.

When the content of the hydrogenated methyl rosinate is within the above preferred range, the occurrence of voids in soldering is more easily suppressed.

≪N,N,N’,N’-tetrakis(2-hydroxypropyl)ethylenediamine≫

The flux in the present embodiment contains N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine.

This N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine is a derivative of diamine, and has an alias of edetol or ethylenediamine-N,N,N',N'-tetra- 2-propanol, with CAS number: 102-60-3.

The content of N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine in the flux is preferably 5% by mass or more and 20% by mass or less with respect to the total amount (100% by mass) of the flux. , more preferably 5 mass% or more and 15 mass% or less. When content of N,N,N',N'-tetrakis(2-hydroxypropyl) ethylenediamine is said preferable range, it will become easy to suppress generation|occurrence|production of a void in brazing adhesion.

The total content of hydrogenated methyl rosinate and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine in the flux is 10% by mass based on the total amount (100% by mass) of the flux. It is preferable that they are 40 mass % or more, 10 mass % or more and 30 mass % or less are more preferable, 15 mass % or more and 30 mass % or less are still more preferable. When content of the sum total of these two components is said preferable range, it will become easy to suppress generation|occurrence|production of a void in soldering.

≪Solvent≫

In the present embodiment, examples of the solvent include water, an alcohol-based solvent, a glycol ether-based solvent, and terpineols.

Examples of the alcohol-based solvent include isopropyl alcohol, 1,2-butanediol, isobornylcyclohexanol, 2,4-diethyl-1,5-pentanediol, 2,2-dimethyl-1,3- Propanediol, 2,5-dimethyl-2,5-hexanediol, 2,5-dimethyl-3-hexyne-2,5-diol, 2,3-dimethyl-2,3-butanediol, 1,1,1- Tris (hydroxymethyl) ethane, 2-ethyl-2-hydroxymethyl-1,3-propanediol, 2,2'-oxy bis (methylene) bis (2-ethyl-1,3-propanediol), 2 ,2-bis(hydroxymethyl)-1,3-propanediol, 1,2,6-trihydroxyhexane, bis[2,2,2-tris(hydroxymethyl)ethyl]ether, 1-ethynyl -1-cyclohexanol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, erythritol, threitol, guaiachol glycerol ether, 3,6-dimethyl-4-octyne-3,6- Diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, etc. are mentioned.

Examples of the glycol ether solvent include diethylene glycol mono-2-ethyl hexyl ether, ethylene glycol monophenyl ether, 2-methylpentane-2,4-diol, diethylene glycol monohexyl ether (hexyl diglycol); Diethylene glycol monohexyl ether (hexyl diglycol), diethylene glycol dibutyl ether, triethylene glycol monobutyl ether, etc. are mentioned.

≪Other ingredients≫

The flux in the present embodiment may contain other components as needed other than hydrogenated methyl rosinate, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, and a solvent. .

As other components, rosins other than hydrogenated methyl rosinate, organic acids, N,N,N',N'-tetrakis(2-hydroxypropyl)amines other than ethylenediamine (hereinafter also referred to as "amines other than edetol") ), a thixotropic agent, a halogen-based activator, a resin component other than a rosin-type resin, a metal deactivator, surfactant, a silane coupling agent, antioxidant, a coloring agent, etc. are mentioned.

Rosins other than hydrogenated methyl rosinate:

Examples of the rosin other than the hydrogenated methyl rosinate include raw material rosin such as gum rosin, wood rosin and tall oil rosin, and derivatives obtained from the raw material rosin. Examples of the derivative include purified rosin, polymerized rosin, hydrogenated rosin, disproportionated rosin and α,β unsaturated carboxylic acid-modified products (acrylated rosin, maleinized rosin, fumarated rosin, etc.), and purified products of the above-mentioned polymerized rosin; hydrides and disproportions; and purified products, hydrides and disproportions of the α,β unsaturated carboxylic acid-modified products.

In the flux in the present embodiment, rosins other than hydrogenated methyl rosinate can be used alone or in combination of two or more.

Among the above, the rosin other than hydrogenated methyl rosin is at least one selected from the group consisting of polymerized rosin, acrylic acid modified rosin, acrylic acid modified hydrogenated rosin, acrylic acid modified disproportionated rosin, hydrogenated rosin, disproportionated rosin, and hydrogenated rosin glycerin ester. It is preferable to use

The content of rosin other than hydrogenated methyl rosinate in the flux is preferably 20 mass% or more and 40 mass% or less, more preferably 25 mass% or more and 40 mass% or less, with respect to the total amount (100 mass%) of the flux; , more preferably 25 mass% or more and 35 mass% or less.

In the flux in the present embodiment, the mixing ratio of hydrogenated methyl rosinate and rosin other than hydrogenated methyl rosinate (hereinafter also referred to as “other rosin”) is a mass ratio expressed by hydrogenated methyl rosinate/other rosin, It is preferable that they are 0.16 or more and 1.0 or less, 0.16 or more and 0.60 or less are more preferable, 0.16 or more and 0.40 or less are still more preferable.

The ratio between the content of other rosin in the flux and the total content of hydrogenated methyl rosinate and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine is, As a mass ratio represented by (hydrogenated methyl rosinate and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine), it is preferably 0.66 or more and 3.0 or less, and more preferably 0.80 or more and 3.0 or less, 0.80 or more and 2.0 or less are more preferable.

Organic acids:

Examples of the organic acid include glutaric acid, adipic acid, azeraic acid, eicosic acid diacid, citric acid, glycolic acid, succinic acid, salicylic acid, diglycolic acid, dipicolinic acid, dibutylaniline diglycolic acid, sveric acid, sebacic acid, thioglycolic acid, dithioglycolic acid, terephthalic acid, dodecane diacid, parahydroxyphenyl acetic acid, picolinic acid, phenyl succinic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, lauric acid, benzoic acid, tartaric acid, isocyanuric acid tris(2-carboxyethyl), glycine, 1,3-cyclohexane dicarboxylic acid, 2,2-bis(hydroxymethyl) propionic acid, 2,2-bis(hydroxymethyl) butanoic acid, 2,3-dihydroxybenzoic acid, 2,4-diethyl glutaric acid, 2-quinoline carboxylic acid, 3-hydroxybenzoic acid, propionic acid, malic acid, p-anisic acid, stearic acid, 12-hydroxystearic acid, oleic acid , linoleic acid, linolenic acid, palmitic acid, pimeric acid, dimer acid, trimer acid, hydrogenated dimer acid which is a hydrogenated product obtained by adding hydrogen to dimer acid, and hydrogenated trimer acid which is a hydrogenated product obtained by adding hydrogen to trimer acid.

In the flux in the present embodiment, one type or two or more types of organic acids can be used.

Among the above, it is preferable to use at least 1 sort(s) selected from the group which consists of malonic acid, glutaric acid, sveric acid, azeraic acid, a stearic acid, and a hydrogenated dimer acid as an organic acid.

The content of the organic acid in the flux is preferably 0 mass % or more and 15 mass % or less, more preferably 5 mass % or more and 15 mass % or less, 7 mass % or more 15 with respect to the total amount (100 mass %) of the flux. % by mass or less is more preferable.

Amines other than N,N,N',N'-tetrakis(2-hydroxypropyl) ethylenediamine (amines other than edetol):

Examples of the amine other than edetol include ethylamine, triethylamine, ethylenediamine, triethylenetetramine, diphenylguanidine, ditolylguanidine, 2-methylimidazole, 2-undecylimidazole, and 2-hepta. Decyl imidazole, 1,2-dimethyl imidazole, 2-ethyl-4-methyl imidazole, 2-phenyl imidazole, 2-phenyl-4-methyl imidazole, 1-benzyl-2-methyl imidazole, 1- Benzyl-2-phenyl imidazole, 1-cyanoethyl-2-methyl imidazole, 1-cyanoethyl-2-undecyl imidazole, 1-cyanoethyl-2-ethyl-4-methyl imidazole, 1 -Cyanoethyl-2-phenyl imidazole, 1-cyanoethyl-2-undecyl imidazolium trimellitate, 1-cyanoethyl-2-phenyl imidazolium trimellitate, 2,4-diamino -6-[2'-Methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]- Ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino- 6-[2'-methylimidazolyl-(1')]-ethyl-s-triazineisocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5- Dihydroxymethyl imidazole, 2-phenyl-4-methyl-5-hydroxymethyl imidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl- 2-Methyl-3-benzyl imidazolium chloride, 2-methyl imidazoline, 2-phenyl imidazoline, 2,4-diamino-6-vinyl-s-triazine, 2,4-diamino-6 -vinyl-s-triazine isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-s-triazine, epoxy-imidazole adduct, 2-methylbenzoimidazole, 2 -Octylbenzoimidazole, 2-pentylbenzoimidazole, 2-(1-ethylpentyl)benzoimidazole, 2-nonylbenzoimidazole, 2-(4-thiazolyl)benzoimidazole, benzimidazole, 2- (2'-hydroxy-5'-methyl phenyl) benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2- (2 '-Hydroxy-3´,5'-di-tert-amyl phenyl) benzotriazole, 2-(2'-hydroxy-5´-tert-octyl) Phenyl) benzotriazole, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol], 6-(2-benzotriazolyl)-4-tert- Octyl-6′-tert-butyl-4′-methyl-2,2′-methylene bisphenol, 1,2,3-benzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]benzo Triazole, carboxybenzotriazole, 1-[N,N-bis(2-ethylhexyl) aminomethyl]methylbenzotriazole, 2,2'-[[(methyl-1H-benzotriazol-1-yl) Methyl]imino]bisethanol, 1-(1′,2′-dicarboxyethyl)benzotriazole, 1-(2,3-dicarboxypropyl)benzotriazole, 1-[(2-ethylhexylamino) methyl]benzotriazole, 2,6-bis[(1H-benzotriazol-1-yl)methyl]-4-methylphenol, 5-methylbenzotriazole, 5-phenyltetrazole, etc. are mentioned. In the flux in the present embodiment, amines other than edetol can be used alone or in combination of two or more.

The content of amines other than edetol in the flux is preferably 0 mass % or more and 10 mass % or less, more preferably 0 mass % or more and 5 mass % or less, with respect to the total amount (100 mass %) of the flux, 0.5 Mass % or more and 1 mass % or less are more preferable.

thixotropic agent:

Examples of the thixotropic agent include a wax-based thixotropic agent, an amide-based thixotropic agent, and a sorbitol-based thixotropic agent.

As a wax-type thixotropic agent, an ester compound is mentioned, for example, Specifically, castor hardened oil etc. are mentioned.

Examples of the amide-based thixotropic agent include monoamide, bisamide, and polyamide, and specifically, lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, and saturated fatty acid Amide, oleic acid amide, erucic acid amide, unsaturated fatty acid amide, p-tolamide, p-toluene methanamide, aromatic amide, hexamethylene hydroxystearic acid amide, substituted amide, methylol stearic acid amide, methylol amide, fatty acid ester amide monoamides such as; Methylene bisstearic acid amide, ethylene bislauric acid amide, ethylene bishydroxy fatty acid (C6-C24 fatty acid carbon atoms) amide, ethylene bishydroxystearic acid amide, saturated fatty acid bisamide, methylene bisoleic acid amide, unsaturated fatty acid bisamide, m -bisamides, such as xylene bisstearic acid amide and aromatic bisamide; polyamides such as saturated fatty acid polyamide, unsaturated fatty acid polyamide, aromatic polyamide, 1,2,3-propane tricarboxylic acid tris(2-methylcyclohexyl amide), cyclic amide oligomer, and acyclic amide oligomer. there is.

The cyclic amide oligomer is an amide oligomer in which dicarboxylic acid and diamine are cyclically polycondensed, an amide oligomer in which tricarboxylic acid and diamine are cyclically polycondensed, an amide oligomer in which dicarboxylic acid and triamine are cyclically polycondensed, tricarboxylic acid and tria An amide oligomer obtained by cyclic polycondensation of min, an amide oligomer obtained by polycondensation of dicarboxylic acid and tricarboxylic acid and diamine, an amide oligomer obtained by polycondensation of dicarboxylic acid and tricarboxylic acid and triamine, dicarboxylic acid and diamine, and and amide oligomers obtained by cyclic polycondensation of triamine, amide oligomers obtained by polycondensation of tricarboxylic acid and diamine and triamine, and amide oligomers obtained by cyclic polycondensation of dicarboxylic acid and tricarboxylic acid with diamine and triamine.

In addition, when the acyclic amide oligomer is an amide oligomer obtained by acyclic polycondensation of monocarboxylic acid and diamine and/or triamine, an amide oligomer obtained by acyclic polycondensation of dicarboxylic acid and/or tricarboxylic acid and monoamine In the case of , etc. can be mentioned. The amide oligomer containing monocarboxylic acid or monoamine, and the monocarboxylic acid and monoamine function as terminal molecules to form an acyclic amide oligomer with a small molecular weight. In addition, when the acyclic amide oligomer is an amide compound obtained by acyclic polycondensation of dicarboxylic acid and/or tricarboxylic acid and diamine and/or triamine, an acyclic high molecular weight amide polymer is obtained. Further, the acyclic amide oligomer includes an amide oligomer in which a monocarboxylic acid and a monoamine are acyclically condensed.

Examples of the sorbitol-based thixotropic agent include dibenzylidene-D-sorbitol, bis(4-methylbenzylidene)-D-sorbitol, (D-)sorbitol, monobenzylidene (-D-)sorbitol, mono(4 -methylbenzylidene)-(D-)sorbitol etc. are mentioned.

In the flux in this embodiment, a thixotropic agent can be used 1 type, or 2 or more types.

Among the above, it is preferable that the said thixotropic agent contains at least 1 sort(s) chosen from the group which consists of a wax-type thixotropic agent and an amide-type thixotropic agent.

It is preferable that a wax-type thixotropic agent contains castor hardened oil.

It is preferable that an amide-type thixotropic agent contains at least 1 sort(s) chosen from the group which consists of polyamide, bisamide, and monoamide.

The content of the thixotropic agent in the flux is preferably 3 mass % or more and 10 mass % or less, more preferably 5 mass % or more and 10 mass % or less, and 6 mass % with respect to the total amount (100 mass %) of the flux. More preferably 9 mass% or less.

Halogen-based activators:

As a halogen-type activator, an organic halogen compound, an amine hydrohalide, etc. are mentioned, for example.

Examples of the organic halogen compound include trans-2,3-dibromo-2-butene-1,4-diol, triaryl isocyanurate hexabromide, 1-bromo-2-butanol, 1- Bromo-2-propanol, 3-bromo-1-propanol, 3-bromo-1,2-propanediol, 1,4-dibromo-2-butanol, 1,3-dibromo-2- and propanol, 2,3-dibromo-1-propanol, 2,3-dibromo-1,4-butanediol, and 2,3-dibromo-2-butene-1,4-diol. .

Examples of the organic halogen compound include halogenated carboxyl compounds, for example, 2-iodobenzoic acid, 3-iodobenzoic acid, 2-iodopropionic acid, 5-iodosalicylic acid, and 5-iodoanthranilic acid. carboxyl iodide compounds such as; Chlorinated carboxyl compounds such as 2-chlorobenzoic acid and 3-chloropropionic acid; and brominated carboxyl compounds such as 2,3-dibromopropionic acid, 2,3-dibromosuccinic acid, and 2-bromobenzoic acid.

The amine hydrohalide is a compound in which an amine and a hydrogen halide are reacted. Examples of the amine here include ethylamine, ethylenediamine, triethylamine, diphenylguanidine, ditolylguanidine, methylimidazole, and 2-ethyl-4-methylimidazole, and hydrogen halide Examples of the examples include hydrides of chlorine, bromine and iodine.

Moreover, as a halogen-type activator, for example, a salt in which an amine and tetrafluoroboric acid (HBF ₄ ) were reacted, and a complex in which an amine and boron trifluoride (BF ₃ ) were reacted can also be used.

In the flux in the present embodiment, one or two or more halogen-based activators can be used.

The content of the organohalogen compound in the flux is preferably 0 mass % or more and 5 mass % or less, more preferably 0.5 mass % or more and 5 mass % or less, 0.5 mass % with respect to the total amount (100 mass %) of the flux. % or more and 3 mass% or less are more preferable.

The content of the amine hydrohalide in the flux is preferably 0 mass% or more and 1 mass% or less with respect to the total amount (100 mass%) of the flux.

Resin components other than rosin-based resins:

Examples of the resin component other than the rosin-based resin include terpene resins, modified terpene resins, terpene phenol resins, modified terpene phenol resins, styrene resins, modified styrene resins, xylene resins, modified xylene resins, acrylic resins, polyethylene resins, and acrylic resins. - A polyethylene copolymer resin, an epoxy resin, etc. are mentioned.

As modified terpene resin, aromatic modified terpene resin, hydrogenated terpene resin, hydrogenated aromatic modified terpene resin, etc. are mentioned. Hydrogenated terpene phenol resin etc. are mentioned as a modified terpene phenol resin. As modified styrene resin, a styrene acrylic resin, styrene maleic acid resin, etc. are mentioned. Examples of the modified xylene resin include phenol-modified xylene resin, alkylphenol-modified xylene resin, phenol-modified resor-type xylene resin, polyol-modified xylene resin, and polyoxyethylene-added xylene resin.

Metal deactivators:

As a metal deactivator, a hindered phenol type compound, a nitrogen compound, etc. are mentioned, for example. When the flux contains either a hindered phenol-based compound or a nitrogen compound, the thickening inhibitory effect of the solder paste is easily enhanced.

The "metal deactivator" as used herein refers to a compound having the ability to prevent deterioration of a metal by contact with a certain kind of compound.

The hindered phenol-based compound refers to a phenol-based compound having a bulky substituent (eg, a branched or cyclic alkyl group such as t-butyl group) at at least one of the ortho positions of phenol.

It does not specifically limit as a hindered phenol type compound, For example, bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionic acid] [ethylene bis(oxyethylene)], N,N '-Hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanamide], 1,6-hexanediolbis[3-(3,5-ditert-butyl-4) -Hydroxyphenyl) propionate], 2,2'-methylenebis[6-(1-methylcyclohexyl)-p-cresol], 2,2'-methylenebis(6-tert-butyl-p-cresol) ), 2,2'-methylene bis (6-tert-butyl-4-ethylphenol), triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate ], 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis-(n-octylthio)-6-( 4-Hydroxy-3,5-di-t-butyl anilino)-1,3,5-triazine, pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4-hydro hydroxyphenyl) propionate], 2,2-thio-diethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3-(3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, N,N'-hexamethylene bis(3,5-di-t-butyl-4-hydroxyhydrocinnamamide), 3,5 -di-tert-butyl-4-hydroxybenzyl phosphonato diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxy benzyl) benzene, N,N'-bis[2-[2-(3,5-di-tert-butyl-4-hydroxyphenyl)ethylcarbonyloxy]ethyl]oxamide, a compound represented by the following formula can be heard

(Wherein, Z is an optionally substituted alkylene group. R ¹ and R ² are each independently an optionally substituted alkyl group, aralkyl group, aryl group, heteroaryl group, cycloalkyl group or heterocycloalkyl group. R ³ and R ⁴ are each independently an optionally substituted alkyl group.)

As a nitrogen compound in a metal deactivator, a hydrazide type nitrogen compound, an amide type nitrogen compound, a triazole type nitrogen compound, a melamine type nitrogen compound, etc. are mentioned, for example.

As the hydrazide-based nitrogen compound, any nitrogen compound having a hydrazide skeleton may be used, and dodecane diacid bis[N2-(2-hydroxybenzoyl)hydrazide], N,N'-bis[3-(3,5-di) -tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, decanedicarboxylic acid disalicilylhydrazide, N-salicylidene-N'-salicylhydrazide, m-nitrobenzhydrazide, 3 -Aminophthalhydrazide, phthalic acid dihydrazide, adipic acid hydrazide, oxalobis(2-hydroxy-5-octylbenzylidenehydrazide), N'-benzoylpyrrolidone carboxylic acid hyrazide, N,N' -bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hydrazine etc. are mentioned.

As the amide-based nitrogen compound, any nitrogen compound having an amide skeleton may be used, and N,N'-bis{2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyl]ethyl} Oxamide etc. are mentioned.

The triazole-based nitrogen compound may be any nitrogen compound having a triazole skeleton, such as N-(2H-1,2,4-triazol-5-yl)salicylamide, 3-amino-1,2,4-triazole , 3-(N-salicilyl)amino-1,2,4-triazole and the like.

As a melamine-type nitrogen compound, what is necessary is just a nitrogen compound which has a melamine skeleton, melamine, a melamine derivative, etc. are mentioned. More specifically, for example, trisaminotriazine, alkylated trisaminotriazine, alkoxyalkylated trisaminotriazine, melamine, alkylated melamine, alkoxyalkylated melamine, N2-butylmelamine, N2,N2-diethylmelamine, N ,N,N',N',N'',N''-hexakis(methoxymethyl)melamine etc. are mentioned.

Surfactants:

Nonionic surfactants, weak cationic surfactants, etc. are mentioned as surfactant.

Examples of the nonionic surfactant include polyethylene glycol, polyethylene glycol-polypropylene glycol copolymer, aliphatic alcohol polyoxyethylene adduct, aromatic alcohol polyoxyethylene adduct, and polyhydric alcohol polyoxyethylene adduct. .

Examples of the weak cationic surfactant include terminal diamine polyethylene glycol, terminal diamine polyethylene glycol-polypropylene glycol copolymer, aliphatic amine polyoxyethylene adduct, aromatic amine polyoxyethylene adduct, polyvalent amine polyoxyethylene adduct can be heard

As surfactants other than the above, for example, polyoxyalkylene acetylene glycols, polyoxyalkylene glyceryl ether, polyoxyalkylene alkyl ether, polyoxyalkylene ester, polyoxyalkylene alkyl amine, polyoxyalkyl Lene alkyl amide etc. are mentioned.

Flux content in solder paste:

It is preferable that content of the flux in the solder paste of this embodiment is 5-95 mass % with respect to the total mass (100 mass %) of the solder paste, It is more preferable that it is 5-50 mass %, It is 5-15 mass % is more preferable.

If the content of the flux in the solder paste is within this range, the thickening inhibitory effect due to the solder powder is sufficiently exhibited. In addition, it becomes easy to realize the effect of the component to be blended with the flux, that is, solder adhesion with less generation of voids.

The solder paste of this embodiment can be manufactured by the manufacturing method common in the art.

A solder paste can be obtained by heating and mixing the components constituting the flux to prepare a flux, and stirring and mixing the brazing powder in the flux. Moreover, in anticipation of the thickening suppression effect in time, you may mix|blend a zirconium oxide powder further separately from the said brazing powder.

As explained above, in the solder paste of this embodiment, it has the alloy composition which used together the specific element together with Sn in a specific ratio, and uses the brazing powder which consists of a brazing alloy of a low alpha dose. In the solder paste in which such a solder powder and a specific flux are combined, it is difficult to cause changes with time, such as a viscosity increase, and it becomes possible to suppress the occurrence of a soft error. In addition, according to the solder paste of this embodiment, by selecting the component mix|blended with a flux, the effect of void suppression can be heightened more at the time of soldering by a reflow method, for example.

Generally, in a braze alloy, when each constituent element which comprises a braze alloy does not function independently, and content of each constituent element is all within a predetermined range, various effects can be exhibited for the first time. According to the braze alloy in embodiment described above, when content of each structural element is the above-mentioned range, the viscosity increase in the time-lapse|temporality of a solder paste can be suppressed, and generation|occurrence|production of a soft error can be suppressed. That is, the solder alloy in this embodiment is useful as a target low α-dose material, and by applying it to formation of solder bumps around a memory, it becomes possible to suppress generation|occurrence|production of a soft error.

In addition, in this embodiment, by adopting a braze alloy containing Ni and Fe, which are high melting point metals that are heated to a high temperature during current refining or processing without actively adding As, in a specific ratio, Achieving suppression of thickening over time of solder paste.

Although the reason why such an effect can be acquired is not certain, it is guessed as follows.

Sn for brazing alloy of low α dose is very high in purity, and when the molten alloy is solidified, the crystal size of Sn becomes large. In addition, the oxide film of Sn also forms a sparse oxide film accompanying it. Here, by adding Ni and Fe, which are refractory metals, the crystal size is reduced and a dense oxide film is formed, so that the reactivity between the alloy and the flux is suppressed, so that it is possible to suppress the thickening of the solder paste over time.

In addition, in the flux in this embodiment, hydrogenated methyl rosinate and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylene against the problem that voids are generated in the soldering part. By using diamine together, it becomes easy to fall the melt viscosity of a solder paste. For this reason, suppression of void generation|occurrence|production becomes possible because the gasified flux component becomes easy to fall out from the inside of a paste.

[Example]

Hereinafter, the present invention will be further described in detail by way of examples, but the present invention is not limited by these examples.

In the present embodiment, unless otherwise specified, "ppb" for the braze alloy composition is "mass ppb", "ppm" is "mass ppm", and "%" is "mass %".

<Production of solder alloy>

(Production Examples 1-444)

The raw metal was melted and stirred to prepare braze alloys having respective alloy compositions shown in Tables 1 to 18, respectively.

For the braze alloy of each production example, evaluation of the α dose was performed as follows. The evaluation result was shown in Table 18 from Table 1.

[α dose]

(1) Verification method 1

The α dose was measured by using the α dose measuring device of the gas flow proportional counter and following the procedures (i), (ii) and (iii) described above.

As a measurement sample, the braze alloy sheet immediately after manufacture was used.

This braze alloy sheet was produced by melting the braze alloy immediately after production and forming it into a sheet having an area of 900 cm ² on one surface.

This measurement sample was placed in an α-dose measuring device, and after letting PR-10 gas flow for 12 hours and leaving it still, the α-dose was measured for 72 hours.

(2) Judgment Criteria 1

○○: The amount of α radiation generated from the measurement sample was 0.002 cph/cm ² or less.

○: The amount of α radiation generated from the measurement sample was greater than 0.002 cph/cm ² and less than or equal to 0.02 cph/cm ² .

x: The amount of α radiation generated from the measurement sample was more than 0.02 cph/cm ² .

If this determination is "○○" or "○", it can be said that it is a soldering material with a low α dose.

(3) Verification method 2

Except for changing the measurement sample, the α dose was measured in the same manner as in (1) verification method 1 above.

As a measurement sample, the braze alloy sheet immediately after production was melted and formed into a sheet shape having an area of 900 cm ² on one side, which was subjected to heat treatment at 100° C. for 1 hour and allowed to cool.

(4) Judgment standard 2

○○: The amount of α radiation generated from the measurement sample was 0.002 cph/cm ² or less.

○: The amount of α radiation generated from the measurement sample was greater than 0.002 cph/cm ² and less than or equal to 0.02 cph/cm ² .

x: The amount of α radiation generated from the measurement sample was more than 0.02 cph/cm ² .

If this determination is "○○" or "○", it can be said that it is a soldering material with a low α dose.

(5) Verification method 3

After storing the braze alloy sheet of the measurement sample for which the α dose was measured in (1) verification method 1 above for one year, the α dose was measured again by following the procedures (i), (ii) and (iii) above. It measured and evaluated the change with time of alpha radiation dose.

(6) Judgment Criteria 3

○○: The amount of α radiation generated from the measurement sample was 0.002 cph/cm ² or less.

○: The amount of α radiation generated from the measurement sample was greater than 0.002 cph/cm ² and less than or equal to 0.02 cph/cm ² .

x: The amount of α radiation generated from the measurement sample was more than 0.02 cph/cm ² .

If this determination is "○○" or "○", it can be said that the amount of α radiation generated does not change with time and is stable. That is, generation|occurrence|production of the soft error in electronic equipment can be suppressed.

As shown in Tables 1-18, as a result of evaluating the α radiation dose for the braze alloys of each Production Example, the braze alloys of Production Examples 1-444 were the braze alloy sheet immediately after production and the braze after heat treatment at 100°C for 1 hour. Regarding the alloy sheet and the braze alloy sheet after storage for one year, it was confirmed that the judgment was "○○".

<Production of solder powder>

The braze alloy of each production example was melted, and braze powder consisting of braze alloy particles each having an alloy composition shown in Tables 1 to 18 by the atomization method and comprising a braze alloy particle group having an average particle diameter of 6 µm was produced.

In addition, about the braze alloy of Production Examples 241 to 296, the braze alloy of each Production Example is melted, and it consists of a braze alloy each having an alloy composition shown in Tables 10 to 12 by the atomization method, and has an average particle diameter of 4 µm. The braze powder which consists of a phosphorus braze alloy particle group was manufactured.

<Preparation of flux>

(Preparation Examples 1-32)

As the resin component, rosin other than hydrogenated methyl rosinate and hydrogenated methyl rosin was used. As rosins other than hydrogenated methyl rosin, polymerized rosin, acrylic acid modified rosin, acrylic acid modified hydrogenated rosin, hydrogenated rosin, disproportionated rosin, and hydrogenated rosin glycerin ester were used.

As organic acids, malonic acid, glutaric acid, sveric acid, azeraic acid, stearic acid, and hydrogenated dimer acid were used.

As the amines, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, 2-phenylimidazole, and ditolylguanidine were used.

As the thixotropic agent, ethylene bishydroxystearic acid amide and hydrogenated castor oil were used.

As the solvent, diethylene glycol monobutyl ether and hexyl diglycol were used.

As the halogen-based activator, trans-2,3-dibromo-2-butene-1,4-diol, which is an organic halogen compound, was used. Moreover, diphenylguanidine HBr salt which is an amine hydrohalide was used.

And each component shown in Tables 19-24 was mixed, and the flux of each preparation example was prepared, respectively.

<Production of Solder Paste>

(Example 1)

Each solder paste was prepared by mixing the flux of Preparation Example 1 and each solder powder composed of the brazing alloy particles of Production Examples 223 to 235 and consisting of a group of braze alloy particles having an average particle diameter of 6 µm.

The mixing ratios of the flux and the solder powder are all mass ratios, and flux: solder powder = 11:89.

(Example 2)

The same procedure as in Example 1 was followed except that the braze powder in Example 1 was changed to a braze powder made of each braze alloy of Production Examples 236 to 240 and comprising a group of braze alloy particles having an average particle diameter of 6 µm. Solder paste was prepared.

(Example 3)

The same procedure as in Example 1 was followed except that the braze powder in Example 1 was changed to a braze powder made of each braze alloy of Production Examples 241 to 296 and comprising a group of braze alloy particles having an average particle diameter of 6 µm. Solder paste was prepared.

(Comparative Example 1)

Each solder paste was prepared by mixing the flux of Preparation Example 2 and each soldering powder of each of the brazing alloys of Production Examples 241 to 296 and consisting of a group of braze alloy particles having an average particle diameter of 6 µm.

The mixing ratios of the flux and the solder powder are all mass ratios, and flux: solder powder = 11:89.

(Comparative Example 2)

Each solder paste was manufactured in the same manner as in Comparative Example 1 except that the flux in Comparative Example 1 was changed to the flux in Preparation Example 3.

(Comparative Example 3)

Each solder paste was manufactured in the same manner as in Comparative Example 1 except that the flux in Comparative Example 1 was changed to the flux in Preparation Example 4.

(Examples 4-31)

Each solder paste was manufactured in the same manner as in Example 3 except that the flux in Example 3 was changed to each flux of Preparation Examples 5-32, respectively.

(Example 32)

Each solder paste was prepared by mixing each flux of Preparation Examples 1 and 5 to 32 and each solder alloy of Preparation Examples 241 to 296 and comprising a group of braze alloy particles having an average particle diameter of 6 µm.

The mixing ratios of the flux and the solder powder are all mass ratios, and flux : solder powder = 35:65.

(Example 33)

Each solder paste was prepared by mixing each flux of Preparation Examples 1 and 5 to 32 and each solder alloy of Preparation Examples 149 to 222 and each solder powder composed of a group of braze alloy particles having an average particle diameter of 6 µm.

The mixing ratios of the flux and the solder powder are all mass ratios, and flux: solder powder = 11:89.

(Example 34)

Each of the fluxes of Preparation Examples 1 and 5 to 32 and each solder alloy of Preparation Examples 297 to 370 were mixed with each solder powder composed of a group of braze alloy particles having an average particle diameter of 6 μm to prepare each solder paste.

The mixing ratios of the flux and the solder powder are all mass ratios, and flux: solder powder = 11:89.

(Example 35)

Each solder paste was prepared by mixing each flux of Preparation Examples 1 and 5-32 and each braze alloy of Preparation Examples 1-74 and each composed of a group of braze alloy particles having an average particle diameter of 6 µm.

The mixing ratios of the flux and the solder powder are all mass ratios, and flux: solder powder = 11:89.

(Example 36)

Each of the fluxes of Preparation Examples 1 and 5 to 32 and each solder alloy of Preparation Examples 371 to 444 were mixed with each solder powder composed of a group of braze alloy particles having an average particle diameter of 6 μm to prepare each solder paste.

The mixing ratios of the flux and the solder powder are all mass ratios, and flux: solder powder = 11:89.

(Example 37)

Each of the fluxes of Preparation Examples 1 and 5 to 32 and each of the solder alloys of Preparation Examples 75 to 148 were mixed with each solder powder composed of a group of braze alloy particles having an average particle diameter of 6 µm to prepare each solder paste.

The mixing ratios of the flux and the solder powder were both mass ratios, and flux : solder powder = 11:89.

(Example 38)

A mixed braze powder was prepared in which both braze alloys of Production Example 257 were used and two braze alloy particle groups having different average particle diameters were shared.

Specifically, a group of braze alloy particles (S1a) made of the braze alloy of Production Example 257 and having an average grain diameter of 6 µm, and a braze alloy particle group (S2a) made of the braze alloy of Production Example 257 and having an average particle diameter of 4 µm (S2a) was mixed at a mass ratio (S1a)/(S2a) = 90/10 to obtain a mixed braze powder.

Then, each of the fluxes of Preparation Examples 1 and 5 to 32 and the mixed solder powder mixed at a mass ratio (S1a)/(S2a) = 90/10 were mixed to prepare each solder paste. The mixing ratios of the flux and the mixed brazing powder are all mass ratios, and flux:mixed brazing powder = 11:89.

(Example 39)

All consist of the braze alloy of Production Example 257, and the mixing ratio of the braze alloy particle group (S1a) having an average particle diameter of 6 µm and the braze alloy particle group (S2a) having an average particle diameter of 4 µm is a mass ratio (S1a)/( Each solder paste was manufactured in the same manner as in Example 38 except that S2a) = 50/50.

<Evaluation>

Using the above solder paste, each evaluation of the difficulty in generating voids and suppression of thickening was performed. In addition, comprehensive evaluation was performed from these evaluation results.

The details are as follows. The evaluation result was shown to Tables 19-26.

[Difficulty in occurrence of voids]

Solder paste was printed on Cu-OSP electrode (N=15) of (phi) 80 micrometers and pitch 150 micrometers using the metal mask at 40 micrometers height. Then, it reflowed in nitrogen atmosphere. The reflow profile was hold|maintained at 160 degreeC for 2 minute(s), and it was set as the temperature up to 260 degreeC after that at 1.5 degreeC/sec.

The transmission image of the soldering part (solder bump) after reflow was observed using the Microfocus X-ray X-ray XVR-160 manufactured by UNi-HiTE SYSTEM, and the void generation rate was calculated|required.

Specifically, transmission observation is performed on the solder bumps from the top to the bottom, a circular solder bump transmission image is obtained, the metal filled portion and the void portion are identified based on the contrast of the color tone, and the void area ratio is determined by automatic analysis. It calculated and made this into the void generation|occurrence|production rate.

Thus, using the calculated|required void generation|occurrence|production rate, the following reference|standard evaluated the difficulty of generation|occurrence|production of a void.

○: When the void generation rate is 10% or less in all 15 soldering parts

×: When a void occurrence rate of more than 10% is included among 15 soldering parts

[Thickening suppression]

(1) Verification method

About the solder paste immediately after manufacture, the viscosity was measured for 12 hours in rotation speed: 10 rpm, 25 degreeC, and air|atmosphere using the Malcom Corporation make: PCU-205.

(2) Judgment criteria

(circle): The viscosity after 12 hours is 1.2 times or less compared with the viscosity when 30 minutes pass from immediately after preparation of a solder paste.

x: The viscosity after 12 hours exceeds 1.2 times compared with the viscosity when 30 minutes pass from immediately after preparation of a solder paste.

If this determination is "(circle)", it can be said that sufficient thickening inhibitory effect was acquired. That is, an increase in the viscosity of the solder paste over time can be suppressed.

[Comprehensive evaluation]

(circle): In Tables 19-26, each evaluation of the difficulty of generation|occurrence|production of a void and thickening suppression was all (circle).

x: In Tables 19-26, at least 1 was x among each evaluation of the difficulty of generation|occurrence|production of a void, and thickening suppression.

As shown in Tables 1-26, in the solder pastes of Examples 1 to 39 comprising each combination of the solder powder and flux to which the present invention is applied, even when any solder paste is used, the viscosity of the solder paste increases with time. It was confirmed that it was suppressed, the occurrence of voids was small, and that it was possible to suppress the occurrence of soft errors.

On the other hand, in the solder pastes of Comparative Examples 1 to 3 containing a flux outside the scope of the present invention, even when any solder paste was used, the evaluation of the difficulty in generating voids was inferior.

Claims (26)

A solder paste comprising solder powder and flux, the solder paste comprising:
The brazing powder includes: U: less than 5 mass ppb, Th: less than 5 mass ppb, Pb: less than 5 mass ppm, As: less than 5 mass ppm, Ni: 0 mass ppm or more and 600 mass ppm or less, and Fe: 0 mass ppm It consists of a braze alloy having an alloy composition of not less than 100 mass ppm and the balance consisting of Sn, satisfying the following formula (1), and having an α dose of 0.02 cph/cm ² or less,
The flux is a solder paste comprising hydrogenated methyl rosinate, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, and a solvent.
20≤Ni+Fe≤700 (1)
(1) In the formula, Ni and Fe each represent content (mass ppm) in the alloy composition. The method according to claim 1,
Further, the alloy composition is a solder paste that satisfies the following formula (1').
40≤Ni+Fe≤200 (1')
(1') In the formula, Ni and Fe each represent content (mass ppm) in the alloy composition. The method according to claim 1 or 2,
Further, the alloy composition, Pb is less than 2 mass ppm, solder paste. 4. The method according to any one of claims 1 to 3,
Further, the alloy composition is, As is less than 2 mass ppm, solder paste. 5. The method according to any one of claims 1 to 4,
Furthermore, the said alloy composition contains at least 1 sort(s) of Ag: 0 mass % or more and 4 mass % or less, and Cu: 0 mass % or more and 0.9 mass % or less. 6. The method according to any one of claims 1 to 5,
Furthermore, the said alloy composition contains at least 1 sort(s) of Bi: 0 mass % or more and 0.3 mass % or less, and Sb: 0 mass % or more and 0.9 mass % or less, Solder paste. 7. The method of claim 6,
Further, the alloy composition satisfies the following formula (2), the solder paste.
0.03≤Bi+Sb≤1.2 (2)
(2) In the formula, Bi and Sb each represent content (mass %) in the alloy composition. 8. The method according to any one of claims 1 to 7,
The braze alloy has an α dose of 0.02 cph/cm ² or less after heat treatment at 100° C. for 1 hour with respect to a braze alloy sheet molded into a sheet shape having an area of 900 cm ² on one side of the braze alloy, solder paste. 9. The method according to any one of claims 1 to 8,
The solder alloy is, the α dose is 0.002 cph/cm ² or less, the solder paste. 10. The method of claim 9,
The solder alloy has an α dose of 0.001 cph/cm ² or less, a solder paste. 11. The method according to any one of claims 1 to 10,
The solder paste, wherein the solder powder is composed of a group of solder alloy particles having an average particle diameter of 0.1 to 15 µm. 11. The method according to any one of claims 1 to 10,
The solder paste in which the said braze powder shares two or more types of braze alloy particle groups from which an average particle diameter differs. 13. The method according to any one of claims 1 to 12,
The solder paste, wherein a content of hydrogenated methyl rosinate in the flux is 5 mass% or more and 20 mass% or less with respect to the total amount of the flux. 14. The method according to any one of claims 1 to 13,
The content of N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine in the flux is 5 mass % or more and 20 mass % or less with respect to the total amount of the flux. 15. The method according to any one of claims 1 to 14,
The total content of hydrogenated methyl rosinate and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine in the flux is 10% by mass or more and 40% by mass or less with respect to the total amount of the flux. , solder paste. 16. The method according to any one of claims 1 to 15,
The flux comprises hydrogenated methyl rosinate, rosin other than hydrogenated methyl rosinate, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, a thixotropic agent, and a solvent. , solder paste. 17. The method of claim 16,
The rosin other than hydrogenated methyl rosin is at least one selected from the group consisting of polymerized rosin, acrylic acid modified rosin, acrylic acid modified hydrogenated rosin, acrylic acid modified disproportionated rosin, hydrogenated rosin, disproportionated rosin, and hydrogenated rosin glycerin ester. . 18. The method of claim 16 or 17,
The solder paste, wherein a content of rosin other than hydrogenated methyl rosinate in the flux is 20 mass% or more and 40 mass% or less with respect to the total amount of the flux. 19. The method according to any one of claims 16 to 18,
The mixing ratio of hydrogenated methyl rosinate and rosin other than hydrogenated methyl rosinate is,
Rosins other than hydrogenated methyl rosinate/hydrogenated methyl rosinate
A solder paste that is 0.16 or more and 1.0 or less as a mass ratio represented by . 20. The method according to any one of claims 16 to 19,
a content of rosin other than hydrogenated methyl rosinate in the flux;
The ratio with the total content of hydrogenated methyl rosinate and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine is
Rosins other than hydrogenated methyl rosinate/(hydrogenated methyl rosinate and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine)
A solder paste that is 0.66 or more and 3.0 or less as a mass ratio represented by . 21. The method according to any one of claims 16 to 20,
The said thixotropic agent contains at least 1 sort(s) selected from the group which consists of a wax-type thixotropic agent and an amide-type thixotropic agent, Solder paste. 22. The method of claim 21,
The amide-based thixotropic agent is a solder paste comprising at least one selected from the group consisting of polyamide, bisamide, and monoamide. 23. The method of claim 21 or 22,
The wax-based thixotropic agent, the solder paste comprising a castor hydrogenated oil. 24. The method according to any one of claims 16 to 23,
The solder paste, wherein the content of the thixotropic agent in the flux is 3 mass% or more and 10 mass% or less with respect to the total amount of the flux. 25. The method according to any one of claims 16 to 24,
The said flux further contains 0 mass % or more and 15 mass % or less of organic acid with respect to the total amount of the said flux. 26. The method according to any one of claims 16 to 25,
The flux further comprises:
0% by mass or more and 10% by mass or less of amines other than N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine,
0 mass % or more and 5 mass % or less of an organic halogen compound, and
0 mass % or more and 1 mass % or less of an amine hydrohalide salt
containing, solder paste.