JP6638180B1 - Flux, solder alloy, joined body, and method for manufacturing joined body - Google Patents

Abstract

An object of the present invention is to provide a flux or the like that sufficiently improves the wettability of a solder alloy containing no Ag. A chlorendic acid and / or anhydride for soldering a solder alloy containing 0.1 to 3.0% by weight of Cu and 0.0040 to 0.0150% by weight of Ge, with the balance being Sn. Flux containing chlorendic acid. [Selection diagram] None

Description

  The present invention relates to a flux, a solder alloy, a joined body, and a method for manufacturing a joined body.

  Fixing and electrical connection of electronic components in electronic equipment, such as mounting of electronic components on a printed circuit board, are generally performed by soldering, which is the most advantageous in terms of cost and reliability.

  Various types of solder alloys used for soldering have been reported, and an Sn-Ag-Cu-based solder alloy is mentioned as an example.

  When soldering, a flux is used for the purpose of removing an oxide film formed on the surface of a substrate, improving the wettability of a solder alloy, and the like (for example, Patent Documents 1 and 2). .

JP 2013126667 A Patent No.6322281

  Regarding the Sn-Ag-Cu solder alloy, from the viewpoint of cost, it is desired to reduce the content of expensive Ag. However, since Ag has a function of ensuring the wettability of the solder alloy, By removing, the wettability deteriorates. On the other hand, it is possible to improve the wettability of the solder alloy by using the flux, but it is difficult to sufficiently improve the wettability of the solder alloy containing no Ag.

  Therefore, the present invention provides a flux for sufficiently improving the wettability of a solder alloy containing no Ag, a solder alloy for which the wettability is sufficiently improved by the flux, and a method for producing a joined body using the flux and the solder alloy. And a joined body manufactured by the method.

  As a result of extensive studies by the present inventors, the use of a flux containing chlorendic acid and / or chlorendic anhydride in combination with a Sn-Cu-Ge solder alloy sufficiently improves the wettability of the solder alloy. They have found that they can do this and have completed the present invention.

The present invention includes the following embodiments.
[1]
Contains chlorendic acid and / or chlorendic anhydride for soldering a solder alloy comprising 0.1-3.0% by weight of Cu and 0.0040-0.0150% by weight of Ge, with the balance being Sn. flux.
[2]
The flux according to [1], wherein the solder alloy further contains 0.0100 to 0.1000% by weight of Ni.
[3]
The flux according to [1] or [2], wherein the solder alloy further contains 0.0020 to 0.0150% by weight of As.
[4]
The flux according to any one of [1] to [3], wherein the soldering is flow soldering.
[5]
The flux according to any one of [1] to [4], wherein the soldering is pallet soldering.
[6]
0.1 to 3.0 wt% Cu and 0.0040 to 0.0150 wt% for soldering to the surface of the substrate whose surface has been treated with a flux comprising chlorendic acid and / or chlorendic anhydride. % Ge, with the balance being Sn.
[7]
The solder alloy according to [6], wherein the solder alloy further contains 0.0100 to 0.1000% by weight of Ni.
[8]
The solder alloy according to [6] or [7], wherein the solder alloy further contains 0.0020 to 0.0150% by weight of As.
[9]
The solder alloy according to any one of [6] to [8], wherein the soldering is flow soldering.
[10]
The solder alloy according to any one of [6] to [9], wherein the soldering is pallet soldering.
[11]
The surface of the substrate whose surface has been treated with a flux containing chlorendic acid and / or chlorendic anhydride contains 0.1 to 3.0% by weight of Cu and 0.0040 to 0.0150% by weight of Ge and the balance A step of soldering a solder alloy composed of Sn to form a joined body.
[12]
The manufacturing method according to [11], wherein the solder alloy further contains 0.0100 to 0.1000% by weight of Ni.
[13]
The manufacturing method according to [11] or [12], wherein the solder alloy further contains 0.0020 to 0.0150% by weight of As.
[14]
The manufacturing method according to any one of [11] to [13], wherein the soldering is flow soldering.
[15]
The manufacturing method according to any one of [11] to [14], wherein the soldering is pallet soldering.
[16]
A joined body obtained by the production method according to any one of [11] to [15].

  ADVANTAGE OF THE INVENTION According to this invention, the flux which fully improves the wettability of the solder alloy which does not contain Ag, the solder alloy whose wettability is sufficiently improved by flux, the method of manufacturing a joined body using the said flux and the said solder alloy And a joined body manufactured by the method.

<Flux and solder alloy>
One embodiment of the present invention is a chlorendic acid for soldering a solder alloy comprising 0.1-3.0 wt% Cu and 0.0040-0.0150 wt% Ge with the balance being Sn. And / or a flux containing chlorendic anhydride.
Also, an embodiment of the present invention provides a method of soldering to a surface of a substrate, which has been treated with a flux containing chlorendic acid and / or chlorendic anhydride, of 0.1 to 3.0% by weight. The present invention relates to a solder alloy containing Cu and 0.0040 to 0.0150% by weight of Ge, with the balance being Sn.

  By using the flux and the solder alloy according to the present embodiment in combination, it is possible to sufficiently improve the wettability of the solder alloy containing no Ag. The soldering is preferably performed by flow soldering. The soldering may be performed by pallet soldering.

  The flux according to the present embodiment contains chlorendic acid and / or chlorendic anhydride. The total content of chlorendic acid and chlorendic anhydride is preferably 0.01 to 10.0% by weight, more preferably 0.05 to 5.0% by weight, and still more preferably 0 to 5.0% by weight, based on the flux. 0.1 to 3.0% by weight. By setting the total content of chlorendic acid and chlorendic anhydride within the above range, the wettability of the solder alloy can be further improved.

  The flux may further contain optional components in addition to chlorendic acid and / or chlorendic anhydride. Examples of the optional component include a solvent, rosin, an activator (excluding chlorendic acid and chlorendic anhydride; the same applies hereinafter), and a matting agent.

Examples of the solvent include water, an alcohol solvent, a glycol ether solvent, and terpineols.
Examples of the alcohol solvent include 2-propanol, ethanol, 1,2-butanediol, isobornylcyclohexanol, 2,4-diethyl-1,5-pentanediol, and 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′-oxybis (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, guaiacol glycerol ether, 3,6-dimethyl-4-octyne-3,6 -Diol, and 2,4,7,9-tetramethyl-5-decyne-4,7-diol.
Examples of glycol ether solvents include diethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, 2-methylpentane-2,4-diol, diethylene glycol monohexyl ether, diethylene glycol dibutyl ether, triethylene glycol monobutyl ether, and hexyl. Diglycol and tetraethylene glycol dimethyl ether.
Although not particularly limited, alcohol solvents are preferable from the viewpoint of volatility. In addition, 2-propanol is preferred from the viewpoint of suppressing esterification between rosin, an organic acid or the like as an activator, and a solvent.
One kind of the solvent may be used alone, or two or more kinds may be used in combination.

  The content of the solvent is preferably 75 to 94% by weight, more preferably 80 to 92% by weight, and still more preferably 85 to 90% by weight based on the flux.

  The rosin includes, for example, acid-modified rosin, purified rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, and rosin ester. Rosin is a non-volatile component contained in pines and the like of Pinaceae plants. Rosins include, for example, tall rosin, gum rosin, and wood rosin. The acid-modified rosin is obtained by treating rosin with an acid. The acid-modified rosin may be hydrogenated. Examples of the acid-modified rosin include acrylic acid-modified rosin, acrylic acid-modified hydrogenated rosin, maleic acid-modified rosin, and maleic acid-modified hydrogenated rosin. Rosin may be used alone or in combination of two or more. When the flux contains rosin, the wettability of the solder alloy can be improved.

  The content of rosin is preferably 3 to 18% by weight, more preferably 6 to 15% by weight, and still more preferably 9 to 12% by weight based on the flux. By setting the rosin content within the above range, the wettability of the solder alloy can be further improved.

  Examples of the activator include an organic acid, a halogen-based activator (eg, an organic halogen compound and an amine hydrohalide), an amine, and an organic phosphorus-based compound (eg, a phosphonate and a phenyl-substituted phosphinic acid). Is mentioned. One activator may be used alone, or two or more activators may be used in combination. When the flux contains an activator, the wettability of the solder alloy can be further improved.

  Examples of organic acids include adipic acid, azelaic acid, eicosane diacid, citric acid, glycolic acid, succinic acid, salicylic acid, diglycolic acid, dipicolinic acid, dibutylaniline diglycolic acid, suberic acid, sebacic acid, and thioglycolic acid. , Terephthalic acid, dodecandioic acid, parahydroxyphenylacetic acid, picolinic acid, phenylsuccinic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, lauric acid, benzoic acid, tartaric acid, tris (2-carboxyethyl) isocyanurate, 1,3-cyclohexanedicarboxylic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butanoic acid, 2,3-dihydroxybenzoic acid, 2,4-diethylglutaric acid, 2- Quinoline carboxylic acid, 3-hydroxybenzoic acid, malic acid, p-anisic acid, Stearic acid, 12-hydroxystearic acid, oleic acid, linoleic acid, linolenic acid, dimer acid, hydrogenated dimer acid, trimer acid, and hydrogenated trimer acid.

  Examples of the organic halogen compound include 1,2,4,5-tetrabromobenzene, trans-2,3-dibromo-2-butene-1,4-diol, and 2,3-dibromo-1,4-butanediol. 2,3-dibromo-1-propanol, 2,3-dichloro-1-propanol, 1,1,2,2-tetrabromoethane, 2,2,2-tribromoethanol, pentabromoethane, tetrabromide Carbon, 2,2-bis (bromomethyl) -1,3-propanediol, meso-2,3-dibromosuccinic acid, chloroalkane, chlorinated fatty acid ester, n-hexadecyltrimethylammonium bromide, triallyl isocyanurate 6 Bromide, 2,2-bis [3,5-dibromo-4- (2,3-dibromopropoxy) phenyl] propane, bis [3,5-dibromo-4- (2 3-dibromo-propoxy) phenyl] sulfone, ethylene bis pentabromodiphenyl benzene, 2-chloromethyl-oxirane, and include bromide bisphenol A type epoxy resin.

  As the amine hydrohalide, for example, boron trifluoride piperidine, stearylamine hydrochloride, diethylaniline hydrochloride, diethanolamine hydrochloride, 2-ethylhexylamine hydrobromide, pyridine hydrobromide, Isopropylamine hydrobromide, cyclohexylamine hydrobromide, diethylamine hydrobromide, monoethylamine hydrobromide, 1,3-diphenylguanidine hydrobromide, dimethylamine hydrobromide Dimethylamine hydrochloride, rosinamine hydrobromide, 2-ethylhexylamine hydrochloride, isopropylamine hydrochloride, cyclohexylamine hydrochloride, 2-pipecholine hydrobromide, 1,3-diphenylguanidine hydrochloride, dimethylbenzyl Amine hydrochloride, hydrazine hydrate hydrobromide, dimethyl Clohexylamine hydrochloride, trinonylamine hydrobromide, diethylaniline hydrobromide, 2-diethylaminoethanol hydrobromide, 2-diethylaminoethanol hydrochloride, ammonium chloride, diallylamine hydrochloride, diallylamine bromide Hydrochloride, monoethylamine hydrochloride, monoethylamine hydrobromide, diethylamine hydrochloride, triethylamine hydrobromide, triethylamine hydrochloride, hydrazine monohydrochloride, hydrazine dihydrochloride, hydrazine monohydrobromide, Hydrazine dihydrobromide, pyridine hydrochloride, aniline hydrobromide, butylamine hydrochloride, hexylamine hydrochloride, n-octylamine hydrochloride, dodecylamine hydrochloride, dimethylcyclohexylamine hydrobromide, ethylenediamine Dihydrobromide, rosin Hydrobromide, 2-phenylimidazole hydrobromide, 4-benzylpyridine hydrobromide, L-glutamate hydrochloride, N-methylmorpholine hydrochloride, betaine hydrochloride, 2-pipecholine hydroiodic acid Salt, cyclohexylamine hydroiodide, 1,3-diphenylguanidine hydrofluoride, diethylamine hydrofluoride, 2-ethylhexylamine hydrofluoride, cyclohexylamine hydrofluoride, ethylamine fluoride Hydrochloride, rosinamine hydrofluoride, boron trifluoride piperidine complex, cyclohexylamine tetrafluoroborate, and dicyclohexylamine tetrafluoroborate.

Amines include, for example, aliphatic amines, aromatic amines, amino alcohols, azoles, amino acids, guanidines, and hydrazides.
Examples of the aliphatic amine include dimethylamine, ethylamine, 1-aminopropane, isopropylamine, trimethylamine, allylamine, n-butylamine, diethylamine, sec-butylamine, tert-butylamine, N, N-dimethylethylamine, isobutylamine, and Cyclohexylamine.
Examples of the aromatic amine include aniline, N-methylaniline, diphenylamine, N-isopropylaniline, and p-isopropylaniline.
Examples of the amino alcohol include 2-aminoethanol, 2- (ethylamino) ethanol, diethanolamine, diisopropanolamine, triethanolamine, N-butyldiethanolamine, triisopropanolamine, and N, N-bis (2-hydroxyethyl). -N-cyclohexylamine, N, N, N ', N'-tetrakis (2-hydroxypropyl) ethylenediamine, and N, N, N', N ", N" -pentakis (2-hydroxypropyl) diethylenetriamine No.
As the azoles, for example, imidazole, 3,5-dimethylpyrazole, benzotriazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methyl Imidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-un Decyl imidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazo Um 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-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4- Methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, -Methylimidazoline, 2-phenylimidazoline, epoxy-imidazole adduct, 2-methylbenzimidazole, 2-octylbenzimidazole, 2-pentylbenzimidazole, 2- (1-ethylpentyl) benzimidazole, 2-nonylbenzimidazole, 2 -(4-thiazolyl) benzimidazole, and benzimidazole.
As amino acids, for example, alanine, arginine, asparagine, aspartic acid, cysteine hydrochloride, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine monohydrochloride, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, Valine, β-alanine, γ-aminobutyric acid, δ-aminovaleric acid, ε-aminohexanoic acid, ε-caprolactam, and 7-aminoheptanoic acid.

  Examples of the phosphonate include 2-ethylhexyl (2-ethylhexyl) phosphonate, n-octyl (n-octyl) phosphonate, n-decyl (n-decyl) phosphonate, and n-butyl (n-butyl) phosphonate. Can be

  Phenyl-substituted phosphinic acids include, for example, phenylphosphinic acid and diphenylphosphinic acid.

  The content of the activator is preferably 0.1 to 12.0% by weight, more preferably 0.3 to 8.0% by weight, and still more preferably 0.5 to 4.0% by weight based on the flux. 0% by weight. By setting the content of the activator within the above range, the wettability of the solder alloy can be further improved.

  Matting agents include, for example, palmitic acid. One type of matting agent may be used alone, or two or more types may be used in combination. When the flux contains a matting agent, the mat of the joint portion of the joined body can be matted, and the appearance inspection of the portion can be facilitated.

  The polishing agent is preferably 0.01 to 4.0% by weight, more preferably 0.05 to 3.0% by weight, and still more preferably 0.1 to 2.0% by weight based on the flux. % By weight. By setting the content of the polishing agent within the above range, the appearance inspection of the joint portion of the joined body can be further facilitated.

  The solder alloy according to this embodiment contains 0.1 to 3.0% by weight of Cu and 0.0040 to 0.0150% by weight of Ge, with the balance being Sn. When the solder alloy contains Ge, wettability can be ensured. The solder alloy may contain unavoidable impurities.

  The content of each component contained in the solder alloy can be measured according to the ICP emission spectroscopy described in JIS Z 3910: 2017.

  The content of Cu is 0.1 to 3.0% by weight, preferably 0.1 to 1.0% by weight, and more preferably 0.1 to 0.75% by weight, based on the solder alloy. It is. By making the Cu content equal to or more than the above lower limit, diffusion (solder corrosion) of the Cu base material can be suppressed. When the content of Cu is equal to or less than the above upper limit, an excessive rise in liquidus temperature can be suppressed, and flow soldering can be performed at an appropriate temperature.

  The content of Ge is 0.0040 to 0.0150% by weight, preferably 0.0040 to 0.0120% by weight, and more preferably 0.0050 to 0.0100% by weight based on the solder alloy. It is. By setting the Ge content within the above range, the wettability of the solder alloy can be further improved.

  The Sn content is preferably 97.0 to 99.9% by weight, more preferably 98.0 to 99.9% by weight, and still more preferably 99.0 to 99.9% by weight with respect to the solder alloy. 9% by weight.

  Examples of the inevitable impurities include Pb, Sb, Bi, Zn, Fe, Al, Cd, Au, and In. The contents of Pb, Sb, Bi and In are preferably 0.10% by weight or less based on the solder alloy. The content of Zn and Al is preferably 0.001% by weight or less based on the solder alloy. The content of Fe is preferably 0.02% by weight or less based on the solder alloy. The content of Cd is preferably 0.002% by weight or less based on the solder alloy. The content of Au is preferably 0.05% by weight or less based on the solder alloy. By setting the content of the inevitable impurities within the above range, it is possible to avoid an adverse effect on the wettability of the solder alloy.

  The solder alloy may further include Ni. When the solder alloy contains Ni, the bonding strength between the solder alloy and the surface of the substrate can be improved.

  The content of Ni is preferably 0.0100 to 0.1000% by weight, more preferably 0.0200 to 0.0900% by weight, and still more preferably 0.0350 to 0. 0750% by weight. By setting the content of Ni within the above range, the bonding strength can be further improved.

  The solder alloy may further include As. When the solder alloy contains As, the oxidation of the solder alloy and the accompanying yellow discoloration can be prevented.

  The content of As is preferably 0.0020 to 0.0150% by weight, more preferably 0.0040 to 0.0120% by weight, and still more preferably 0.0080 to 0. 0100% by weight. When the content of As is within the above range, oxidation of the solder alloy and discoloration (yellow) accompanying the oxidation can be further prevented.

<Joint body and its manufacturing method>
In one embodiment of the present invention, the surface of the substrate that has been treated with a flux containing chlorendic acid and / or chlorendic anhydride has 0.1 to 3.0% by weight of Cu and 0.0040 to 0.0150. The present invention relates to a method for manufacturing a joined body, which includes a step of forming a joined body by soldering a solder alloy containing Ge by weight and the remainder of which is made of Sn (hereinafter, referred to as a “joining step”).
Further, one embodiment of the present invention relates to a joined body obtained by the above-described manufacturing method.

  The details of the flux and the solder alloy used in the manufacturing method according to the present embodiment are as described in the above item of <Flux and solder alloy>.

  Prior to the bonding step, the manufacturing method according to the present embodiment further includes a step of treating the surface of the substrate with a flux containing chlorendic acid and / or chlorendic anhydride (hereinafter, referred to as a “pretreatment step”). Is also good.

  The treatment method in the pretreatment step and the joining method in the joining step are not particularly limited, and a method generally practiced in the present technical field can be adopted. The soldering is preferably performed by flow soldering. The soldering may be performed by pallet soldering.

  The joined body includes a substrate, a solder alloy soldered to the surface of the substrate, and flux residues. Examples of the substrate include a printed wiring board. Examples of the joined body include a printed circuit board in which electronic components are attached to a printed wiring board.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the technical scope of the present invention is not limited thereto.

Fluxes and solder alloys having the compositions shown in the following table were prepared, and the wettability rate was evaluated based on the zero cross time in Menisco measurement. The results are shown in Tables 1A to 6E. The evaluation criteria for the wettability rate are as follows.
〇: Zero cross time 5 seconds or less ×: Zero cross time 5 seconds or more

Menisco conditions are as follows.
・ Solid sample: copper plate (width 5 mm x length 25 mm x thickness 0.5 mm; no oxidation treatment, etc.)
・ Solder bath temperature: 280 ℃
・ Immersion speed: 20 mm / sec
・ Immersion depth: 5mm
・ Measurement time: 10 sec
・ Flux treatment: Immerse copper plate in flux (immersion depth about 10mm)

Table 1A shows the results for the case of using and not using chlorendic acid and / or chlorendic anhydride for the Sn-Cu-Ge solder alloy.
Table 2A shows the results with and without using chlorendic acid and / or chlorendic anhydride with respect to the Sn-Cu-Ni-Ge solder alloy.
Table 3A shows the results obtained with and without using chlorendic acid and / or chlorendic anhydride with respect to the Sn-Cu-based solder alloy.
Table 4A shows the results when the composition of the solder alloy was changed.
Tables 5A and 6A show the results when the flux composition was changed.

  Tables 1B to 6B correspond to Tables 1A to 6A, respectively, except that the solder alloy further includes 0.0020 wt% As.

  Tables 1C to 6C correspond to Tables 1A to 6A, respectively, except that the solder alloy further includes 0.0050 wt% As.

  Tables 1D to 6D correspond to Tables 1A to 6A, respectively, except that the solder alloy further includes 0.0100 wt% As.

  Tables 1E to 6E correspond to Tables 1A to 6A, respectively, except that the solder alloy further includes 0.0150 wt% As.

<Pallet solderability>
A pallet having an opening at a place where the evaluation board (Senju Metal Industry Co., Ltd. evaluation board H12-06, size: 100 mm × 120 mm, thickness: 1.6 mm, number of soldering points: 272) is to be soldered. Attached to the mask. After that, when soldering was performed on the evaluation substrate attached to the pallet mask under the following soldering conditions, pallet soldering could be performed.

(Soldering conditions)
Soldering equipment: "SPF-300" manufactured by Senju Metal Industry Co., Ltd.
Flux coating device: Spray fluxer (“SSF-300” manufactured by Senju Metal Industry Co., Ltd.)
Flux application amount: 70 mL / m ²
Conveyor speed: 1m / min
Preheat temperature: 100 ° C
Solder bath temperature: 260 ° C

Claims (6)

0.1 to 1.0 wt% Cu and 0.0040 to 0.0150 wt% for soldering to the surface of a substrate whose surface has been treated with a flux comprising chlorendic acid and / or chlorendic anhydride. % Ge, the balance being Sn,
The solder alloy further comprises 0.0020 to 0.0150% by weight of As;
The solder alloy, wherein the solder alloy further comprises 0.0100 to 0.1000% by weight of Ni.   The solder alloy according to claim 1, wherein the soldering is a flow soldering.   The solder alloy according to claim 1, wherein the soldering is pallet soldering. The surface of the substrate whose surface has been treated with a flux containing chlorendic acid and / or chlorendic anhydride contains 0.1 to 1.0% by weight of Cu and 0.0040 to 0.0150% by weight of Ge, and the balance Is a method of manufacturing a joined body, comprising a step of soldering a solder alloy made of Sn to form a joined body,
The solder alloy further comprises 0.0020 to 0.0150% by weight of As;
The above method, wherein the solder alloy further contains 0.0100 to 0.1000% by weight of Ni.   The manufacturing method according to claim 4, wherein the soldering is a flow soldering. The method according to claim 4, wherein the soldering is pallet soldering.