CN113905847A

CN113905847A - Solder joint failure inhibitor, flux and solder paste

Info

Publication number: CN113905847A
Application number: CN202180003711.2A
Authority: CN
Inventors: 永井智子; 髙木和顺; 浅见爱; 髙木善范
Original assignee: Senju Metal Industry Co Ltd
Current assignee: Senju Metal Industry Co Ltd
Priority date: 2020-03-30
Filing date: 2021-03-11
Publication date: 2022-01-07
Anticipated expiration: 2041-03-11
Also published as: TW202138470A; TWI748901B; CN113905847B; JP6845452B1; JP2021159921A; WO2021200010A1

Abstract

Provided are a solder joint failure inhibitor, a flux and a solder paste, which can inhibit the occurrence of joint failure. The flux of the present invention comprises a base resin, an activator, a thixotropic agent, a solvent, and a solder joint failure inhibitor, which is a solder joint failure inhibitor comprising a compound represented by the following chemical formula (11): in the chemical formula (11), R⁹And R¹⁰Each independently is a saturated or unsaturated linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, R¹¹And R¹²Each independently is carboxy, or R¹¹And R¹²They may also be crosslinked to form carboxylic anhydride groups.

Description

Solder joint failure inhibitor, flux and solder paste

Technical Field

The invention relates to a solder joint failure inhibitor, a flux and a solder paste.

Background

In recent years, with the weight reduction and miniaturization of electronic devices, semiconductor packages such as BGA (Ball Grid Array) are used (for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2008-71779

Disclosure of Invention

Problems to be solved by the invention

However, since semiconductor packages such as BGA are made of various materials, the semiconductor packages are bent due to the difference in thermal expansion coefficient. In addition, the semiconductor package is made thinner, and the amount of warpage of the package increases. Therefore, the solder bump and the solder paste are detached from the substrate, and the pad (soldered portion) is not subjected to oxidation removal by the flux, leaving an oxide film on the pad surface. Further, even if the solder paste and the substrate are brought into contact again, the activity (wettability) of the flux is lowered by heat, and thus the removal of the oxidation by the flux is also insufficient. Therefore, the electronic component and the substrate are not bonded, and a problem of poor bonding occurs.

Accordingly, an object of the present invention is to provide a solder joint failure inhibitor, flux and solder paste which can inhibit the occurrence of joint failure.

Means for solving the problems

To achieve the above object, the solder joint failure inhibitor (hereinafter also referred to as "inhibitor") of the present invention comprises a compound represented by the following chemical formula (11):

[ solution 11]

In the chemical formula (11),

R⁹and R¹⁰Each independently a saturated or unsaturated straight chain, branched or cyclic alkyl group having 1 to 18 carbon atoms,

R¹¹and R¹²Each of which is independently a carboxyl group,

or R¹¹And R¹²They may also be crosslinked to form carboxylic anhydride groups.

The flux of the present invention comprises a matrix resin, an activator, a thixotropic agent, a solvent and a solder joint failure inhibitor,

the solder joint failure inhibitor is the solder joint failure inhibitor of the present invention.

The solder paste of the present invention comprises a flux and solder powder, and the flux is the flux of the present invention.

ADVANTAGEOUS EFFECTS OF INVENTION

The invention can restrain poor welding of solder.

Detailed Description

< inhibitor of solder Joint failure >

The solder joint failure inhibitor of the present invention comprises a compound of the following chemical formula (11).

[ solution 11]

In the chemical formula (11),

R¹¹and R¹²Each of which is independently a carboxyl group,

The solder joint failure inhibitor of the present invention is characterized by containing the compound of the chemical formula (11), and other configurations and conditions are not particularly limited.

The present inventors have conducted extensive studies and found that the poor junction can be suppressed by allowing the inhibitor of the present invention to coexist, and established the present invention. Therefore, the inhibitor of the present invention can inhibit poor solder bonding.

In the present invention, the term "poor bonding" means, for example, that no bonding is formed between the solder and the object of soldering (no Wet Open: NWO). The "poor bonding" can be measured by, for example, resistance measurement. In the present invention, "suppression of a bonding failure" means, for example, that when bonding is performed using a comparative solder or solder paste having the same composition except that the inhibitor of the present invention is not included, the frequency of occurrence of a bonding failure is significantly reduced. The frequency of occurrence of the poor engagement can be performed based on the NWO evaluation test described later.

In the chemical formula (11), R⁹And R¹⁰Each independently is a saturated or unsaturated linear, branched or cyclic alkyl group having 1 to 18 carbon atoms. R⁹Preferably a saturated straight-chain alkyl group having 1 to 18 carbon atoms, more preferably a saturated straight-chain alkyl group having 4 to 8 carbon atoms, and further preferably a pentyl group (-C)₅H₁₁) Hexyl (-C)₆H₁₃) Or heptyl (-C)₇H₁₅)。R¹⁰Preferably a saturated straight-chain alkyl group having 1 to 18 carbon atoms, more preferably a saturated straight-chain alkyl group having 5 to 9 carbon atoms, and still more preferably a hexyl group (-C)₆H₁₂) Heptyl (-C)₇H₁₄) Or octyl (-C)₈H₁₆). In the chemical formula (11), R⁹For example, the linear alkyl group is a saturated linear alkyl group having 1 to 18 carbon atoms, R¹⁰Is a saturated straight-chain alkyl group having 1 to 18 carbon atoms.

R¹¹And R¹²Each independently is a carboxyl group, or may be crosslinked to form a carboxylic anhydride group. The carboxylic anhydride group means, for example, a substituent containing a carboxylic anhydride. The crosslinking is, for example, R¹¹And R¹²Forming a ring structure.

In one embodiment, the compound represented by chemical formula (11) is preferably a compound represented by chemical formula (12) below.

[ solution 12]

In one embodiment, the compound represented by chemical formula (11) is preferably a compound represented by chemical formula (13) below.

[ solution 13]

The compound represented by the above chemical formula (11) can be produced, for example, by reacting a compound represented by the following chemical formula (15) with maleic anhydride. In the reaction, the amount ratio of the compound represented by the following chemical formula (15) may be set to, for example, not less than the equivalent of maleic anhydride, preferably 1 to 1.5 times the equivalent. Specifically, the compound represented by the formula (15) may be set to 0.01 to 3% by weight, preferably 0.01 to 1% by weight, based on maleic anhydride, for example. The reaction temperature is, for example, 30 to 150 ℃ and preferably 40 to 100 ℃. The reaction is carried out for 0.5 to 20 hours in an atmosphere of an inert gas such as nitrogen or a rare gas. Preferably 0.5 to 10 hours.

[ solution 15]

R⁹-CH＝CH-CH＝CH-R¹⁰-COOH…(15)

< flux >

The flux of the present invention comprises a matrix resin, an activator, a thixotropic agent, a solvent and the solder joint failure inhibitor of the present invention as described above. The flux of the present invention is characterized by containing the inhibitor of the present invention, and other constitution and conditions are not particularly limited. The flux of the present invention may be applied with the description of the inhibitor of the present invention. The flux of the present invention can suppress the occurrence of poor solder joint during solder joint.

The base resin is not particularly limited, and for example, polyethylene glycol, rosin (rosin resin), and the like can be exemplified. Examples of the rosin include raw material rosins such as gum rosin, wood rosin and tall oil rosin, and derivatives obtained from the raw material rosin. The derivative may be exemplified by purified rosin; hydrogenated rosin; disproportionating rosin; polymerized rosin, and purified products, hydrogenated products and disproportionated products of the polymerized rosin, modified products of alpha, beta unsaturated carboxylic acid (acrylated rosin, maleated rosin, fumarated rosin and the like), and purified products, hydrogenated products and disproportionated products of the modified products of alpha, beta unsaturated carboxylic acid and the like. The rosin may be used alone or in combination of two or more. In addition, the base resin may further contain at least one or more resins selected from the group consisting of terpene resins, modified terpene resins, terpene phenol resins, modified terpene phenol resins, styrene resins, modified styrene resins, xylene resins, and modified xylene resins, for example, in place of or in addition to the rosin resin. Examples of the modified terpene resin include an aromatic modified terpene resin, a hydrogenated aromatic modified terpene resin, and the like. Examples of the modified terpene phenol resin include hydrogenated terpene phenol resins and the like. Examples of the modified styrene resin include styrene acrylic resin and styrene maleic acid resin. Examples of the modified xylene resin include phenol-modified xylene resin, alkylphenol-modified xylene resin, phenol-modified methyl xylene resin, polyol-modified xylene resin, and polyoxyethylene-addition xylene resin.

The amount of the base resin to be blended is not particularly limited, and is, for example, 10 mass% or more and 60 mass% or less (10 to 60 mass%), preferably 20 mass% or more and 50 mass% or less (20 to 50 mass%) based on the total amount of the flux.

The activator reduces and removes oxides on the surface of the solder joint and the powder solder to clean the solder joint and enhance wettability of the molten solder, and has a function of causing the molten solder to metallically adhere to the solder joint. Examples of the activator include organic acids, organic halides, amine hydrohalides, and the like. Examples of the organic acid include malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, suberic acid, pimelic acid, sebacic acid, dodecanedioic acid, eicosanedioic acid, glycolic acid, salicylic acid, diglycolic acid, pyridine-2-carboxylic acid, phenylsuccinic acid, phthalic acid, fumaric acid, maleic acid, benzoic acid, terephthalic acid, lauric acid, stearic acid, 12-hydroxystearic acid, 2-bis (hydroxymethyl) propionic acid, and the like. Examples of the organic halide include 1-bromo-2-propanol, 3-bromo-1, 2-propanediol, 1-bromo-2-butanol, 1, 3-dibromo-2-propanol, 2, 3-dibromo-1-propanol, 1, 4-dibromo-2-butanol, 2, 3-dibromo-1, 4-butanediol, trans-2, 3-dibromo-2-butene-1, 4-diol and the like. The amine hydrohalide is a compound obtained by reacting an amine such as ethylamine, diethylamine, triethylamine, ethylenediamine, cyclohexylamine, 1, 3-diphenylguanidine, 1, 3-di-o-tolylguanidine, 1-o-tolylbiguanide, etc. with a hydrogen halide such as a hydride of chlorine, bromine, iodine, etc. The activating agent may be used alone or in combination of two or more. The amount of the activator to be blended is not particularly limited, and is, for example, 1 mass% or more and 20 mass% or less (1 to 20 mass%), preferably 5 mass% or more and 15 mass% or less (5 to 15 mass%) based on the total amount of the flux.

The thixotropic agent has the effects of preventing separation of the flux from other components, improving storage stability, and improving flow characteristics to improve transferability at printing and discharging. Examples of the thixotropic agent include wax-based thixotropic agents, amide-based thixotropic agents, and the like. Examples of the wax thixotropic agent include hydrogenated castor oil and the like. Examples of the amide-based thixotropic agent include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, saturated fatty acid amide, oleic acid amide, erucic acid amide, unsaturated fatty acid amide, p-tolylmethane amide, aromatic amide, methylenebisstearic acid amide, ethylenebislauric acid amide, ethylenebishydroxystearic acid amide, saturated fatty acid bisamide, methylenebisoleic acid amide, unsaturated fatty acid bisamide, m-xylylenebisstearic acid amide, aromatic bisamide, saturated fatty acid polyamide, unsaturated fatty acid polyamide, aromatic polyamide, substituted amide, hydroxymethylstearic acid amide, hydroxymethylamide, fatty acid ester amide, and the like. The thixotropic agent may be used alone or in combination of two or more. The amount of the thixotropic agent to be blended is not particularly limited, and is, for example, 1 mass% or more and 15 mass% or less (1 to 15 mass%), preferably 5 mass% or more and 10 mass% or less (5 to 10 mass%) based on the total amount of the flux.

Examples of the solvent include alcohol solvents, glycol ether solvents, ester solvents, terpineol solvents, and the like. Examples of the alcohol solvent include 1, 2-butanediol, isobornyl cyclohexanol, 2, 4-diethyl-1, 5-pentanediol, 2-dimethyl-1, 3-propanediol, 2, 5-dimethyl-2, 5-hexanediol, 2-butyl-2-ethyl-1, 3-propanediol, 2, 5-dimethyl-3-hexyne-2, 5-diol, 2, 3-dimethyl-2, 3-butanediol, 2-methylpentane-2, 4-diol, 1, 1, 1-tris (hydroxymethyl) ethane, 2-ethyl-2-hydroxymethyl-1, 3-propanediol, 2' -oxybis (methylene) bis (2-ethyl-1, 3-propanediol), 2, 2-bis (hydroxymethyl) -1, 3-propanediol, 1, 2, 6-hexanetriol, bis [2, 2, 2-tris (hydroxymethyl) ethyl ] ether, 1-ethynyl-1-cyclohexanol, 1, 4-cyclohexanediol, 1, 4-cyclohexanedimethanol, 3, 6-dimethyl-4-octyne-3, 6-diol, 2, 4, 7, 9-tetramethyl-5-decyne-4, 7-diol, and the like. Examples of the glycol ether solvent include diethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, diethylene glycol monohexyl ether, diethylene glycol dibutyl ether, triethylene glycol monobutyl ether, tripropylene glycol methyl ether, dipropylene glycol butyl ether, tripropylene glycol butyl ether, triethylene glycol butyl methyl ether, and tetraethylene glycol dimethyl ether. Examples of the ester solvent include diisobutyl succinate, dibutyl succinate, dimethyl adipate, diethyl adipate, dibutyl adipate, diisopropyl adipate, diisobutyl adipate, diisodecyl adipate, dibutyl maleate, dimethyl sebacate, diethyl sebacate, dibutyl sebacate, dioctyl sebacate, and diisopropyl sebacate. The solvent may be used alone or in combination of two or more.

The amount of the solvent to be blended is not particularly limited, and may be, for example, the remainder of the other components. Specifically, the amount of the solvent is, for example, 10 mass% or more and 60 mass% or less (10 to 60 mass%), preferably 25 mass% or more and 50 mass% or less (25 to 50 mass%) based on the total amount of the flux.

In the flux of the present invention, the inhibitor may be used alone or in combination of two or more kinds, for example. The inhibitor is preferably a compound represented by the chemical formula (12) or (13), or a mixture thereof, for example, from the viewpoint that poor solder bonding can be better inhibited.

The amount of the inhibitor, i.e., the amount of the compound represented by the chemical formula (11) to be blended may be more than 0 mass% based on the entire mass of the flux, and is preferably 5 mass% or more, 25 mass% or less (5 to 25 mass%), 5 mass% or more, 24 mass% or less (5 to 24 mass%), or 5 mass% or more, 20 mass% or less (5 to 20 mass%), more preferably 10 mass% or more, 25 mass% or less (10 to 25 mass%), 10 mass% or more, 24 mass% or less (10 to 24 mass%), or 10 mass% or more, 20 mass% or less (10 to 20 mass%), further preferably 16 mass% or more, 25 mass% or less (16 to 25 mass%), 16 mass% or more, 24 mass% or less (16 to 24 mass%), or 16 mass% or more from the viewpoint of better suppressing poor solder bonding, 20% by mass or less (16 to 20% by mass). When the inhibitor includes two or more kinds of inhibitors, the amount of the inhibitor to be blended may be, for example, the amount of one kind of inhibitor to be blended or the total amount of the amounts of two or more kinds of inhibitors to be blended, but the latter is preferable.

When the inhibitor is a compound represented by the chemical formula (12) or (13), the amount of the compound represented by the chemical formula (12) or (13) to be blended may be, for example, more than 0 mass% with respect to the entire mass of the flux, and is preferably 5 mass% or more, 25 mass% or less (5 to 25 mass%), 5 mass% or more, 24 mass% or less (5 to 24 mass%), or 5 mass% or more, 20 mass% or less (5 to 20 mass%), more preferably 10 mass% or more, 25 mass% or less (10 to 25 mass%), 10 mass% or more, 24 mass% or less (10 to 24 mass%), or 10 mass% or more, 20 mass% or less (10 to 20 mass%), further preferably 16 mass% or more, 25 mass% or less (16 to 25 mass%), 16 mass% or more, 24 mass% or less (16 to 24 mass%), or 16 mass% or more and 20 mass% or less (16 to 20 mass%).

The flux of the present invention may further comprise an amine. Examples of the amine include ethylamine, diethylamine, triethylamine, ethylenediamine, cyclohexylamine, 1, 3-diphenylguanidine, 1, 3-di-o-tolylguanidine, 1-o-tolylbiguanide, imidazole, 2-ethylimidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1, 2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-methyl-2-phenylimidazole, 1-benzyl-2-methylimidazole and 1-benzyl-2-phenylimidazole.

The amount of the amine to be blended is not particularly limited, and is, for example, 0.1 mass% or more and 5 mass% or less (0.1 to 5 mass%), preferably 1 mass% or more and 5 mass% or less (1 to 5 mass%) based on the total amount of the flux.

The flux of the present invention may further comprise an antioxidant. The oxidation inhibitor can suppress oxidation of the solder powder. Examples of the antioxidant include hindered phenol-based antioxidants, bisphenol-based antioxidants, and polymer-based antioxidants. The antioxidant may be used alone or in combination of two or more.

The amount of the antioxidant to be blended is not particularly limited, and is, for example, 1 mass% or more and 10 mass% or less (1 to 10 mass%), preferably 1 mass% or more and 5 mass% or less (1 to 5 mass%) based on the total amount of the flux.

The flux of the present invention may further contain, for example, additives such as a colorant, a defoaming agent, a surfactant, a matting agent and the like. The additive may be used alone or in combination of two or more. The amount of the additive to be blended is not particularly limited, and is, for example, 0 mass% or more and 5 mass% or less (0 to 5 mass%) with respect to the total amount of the flux.

< solder paste >

The solder paste of the present invention contains a flux and solder powder as described above, and the flux is the flux of the present invention. The solder paste of the present invention is characterized by containing the flux of the present invention, and other constitution and conditions are not particularly limited. The solder paste of the present invention can suppress poor solder joint. The solder paste of the present invention can be applied to the description of the inhibitor and flux of the present invention.

The solder powder may also be referred to as metal powder, for example. The solder powder is not particularly limited, and for example, a solder containing no Pb is preferable, and examples thereof include a single Sn, Sn-Ag based, Sn-Cu based, Sn-Ag-Cu based, Sn-Bi based, and Sn-In based solder, and solder powders obtained by adding Sb, Bi, In, Cu, Zn, As, Ag, Cd, Fe, Ni, Co, Au, Ge, P, and the like to these alloys.

The particle size of the solder powder is not particularly limited, and may be, for example, in the range of 10 to 60 μm, but may be larger or smaller. The amount of the solder powder blended with the flux of the present invention may be appropriately set according to the particle diameter of the solder powder. The amount of the solder powder and the flux of the present invention may be set to 8 to 15 mass% and 85 to 92 mass% respectively.

< electronic Circuit Board >

An electronic circuit board of the present invention includes a solder joint portion in which 2 members are joined by solder, and the solder joint portion includes the solder joint failure inhibitor of the present invention. The electronic circuit board of the present invention is characterized in that the solder bonding portion contains the inhibitor of the present invention, and other configurations and conditions are not particularly limited. The electronic circuit board of the present invention can be applied to the description of the inhibitor, flux and solder paste of the present invention.

The electronic circuit board may be a printed board or a flexible printed board. The use of the electronic circuit substrate is not particularly limited.

Examples of the 2 components include a combination of an electronic component or a lead thereof and a substrate wiring, a combination of substrate wirings, and the like. The electronic component is not particularly limited, and any electronic component mounted on an electronic circuit board can be exemplified.

< electronic apparatus >

The electronic device of the present invention includes the electronic circuit board of the present invention. The electronic device of the present invention is characterized by including the electronic circuit board of the present invention, and other configurations and conditions are not particularly limited. The electronic appliance of the present invention can be applied to the description of the inhibitor of the present invention, the solder paste and the electronic circuit substrate.

The electronic device is not particularly limited, and any electronic device having an electronic circuit board can be exemplified, and specific examples thereof include information devices such as personal computers and tablet terminals; electrical products such as televisions, refrigerators, washing machines, and the like; air conditioning equipment such as an air conditioner, and the like.

< method of soldering >

The soldering method of the present invention includes a step of bonding a 1 st object to be bonded and a 2 nd object to be bonded in the presence of a solder joint failure inhibitor, wherein the solder joint failure inhibitor is the solder joint failure inhibitor of the present invention. The welding method of the present invention is characterized in that the joining step is carried out in the presence of the inhibitor of the present invention, and other steps and conditions are not particularly limited. The soldering method of the present invention can suppress the occurrence of poor solder joint. The soldering method of the present invention can be applied to the description of the inhibitor, flux and solder paste of the present invention.

The joining step may be performed in a flow type or a reflux type. The bonding step can be carried out using, for example, a solder to which the flux of the present invention is added (contained) or the solder paste of the present invention.

In the case of using the solder containing the flux of the present invention, in the bonding step, the 1 st object to be bonded and the 2 nd object to be bonded are melted by heating the 1 st object to be bonded and the 2 nd object to be bonded and the solder containing the flux, whereby the 1 st object to be bonded and the 2 nd object to be bonded can be bonded by the solder.

When the solder paste of the present invention is used, the soldering method of the present invention is carried out, for example, as follows. Before the joining step, the solder paste of the present invention is transferred (adhered) to a joint portion joining the 1 st object to be joined and the 2 nd object to be joined in the 1 st object to be joined or the 2 nd object to be joined. Next, the joint of the 1 st object to be joined or the 2 nd object to be joined to which the solder paste of the present invention is transferred is brought into contact with the other object to be joined. Then, the solder paste of the present invention is heated and melted to join the 1 st object to be joined and the 2 nd object to be joined, and the 1 st object to be joined and the 2 nd object to be joined are joined by the solder paste of the present invention.

[ examples ] A method for producing a compound

Examples of the present invention are explained below. However, the present invention is not limited to the following examples.

(example 1)

It was confirmed that occurrence of poor solder bonding could be suppressed by the inhibitor of the present invention.

< preparation of flux >

The compositions of examples 1 to 10 and comparative example 1 are shown in table 1 below. The fluxes of examples 1 to 10 and comparative example 1 were uniformly dispersed by mixing and heating to melt the respective materials in the blending amounts (mass%) shown in table 1 below. Inhibitor E of table 1 below uses a mixture of the compounds of the chemical formulae (12) and (13) belonging to the chemical formula (11).

[ TABLE 1]

< preparation of solder paste >

Using the respective fluxes of the compositions shown in the respective examples and the comparative example, solder pastes were prepared. Specifically, the solder pastes of examples 1 to 10 and comparative example 1 were prepared by mixing the above-mentioned fluxes in an amount of 12 mass% and solder powders (particle size: 20 to 38 μm) of Sn-3Ag-0.5Cu (melting point 217 ℃ C.) in an amount of 88 mass% based on the entire solder paste.

< NWO evaluation experiment >

Each of the solder pastes was evaluated for the occurrence of poor bonding (Non Wet Open: NWO). Specifically, the opening diameter was used on the substrate (Cu-OSP handle glass epoxy pad substrate): 0.30mm, mask thickness 0.12mm (120 μm), number of openings: each of the solder pastes was printed on 132 metal masks, and BGA of 0.5mm pitch with solder bumps was mounted thereon. Setting the heating rate of heating from 25 ℃ (room temperature) to 130 ℃ in a reflux furnace to be 3 ℃/s, the heating rate of heating from 130 ℃ to 190 ℃ to be 1.0 ℃/s, the peak temperature to be 200 ℃, and cooling after heating. After cooling, the substrate and the BGA were peeled. Regarding the post-peeling NWO evaluation, the post-printing solder paste was adhered to the solder mass, and the portion where the solder paste was not adhered to the substrate side was regarded as the portion where NWO was generated. Then, the number of sites where NWO occurs is calculated, and when the number is 20 or less, it is determined that the bonding is good.

In general, since the BGA is bent by heating, there are portions where the substrate and BGA tend to separate during reflow soldering. At this time, the solder paste rises from the substrate side to the BGA side, and the oxide film of the pad cannot be removed, resulting in poor bonding. That is, by this evaluation method, a potential site where NWO may occur can be predicted. In addition, when there are a plurality of such potential portions, for example, even when the substrate and the BGA are not separated or the printed portion is surrounded by a portion that is not lifted, it is difficult to suppress the bending of the BGA, and NWO occurs.

The above-mentioned NWO evaluation test is an example, and the conditions in the NWO evaluation test are not limited thereto. The heating conditions in the NWO evaluation experiment may be changed, for example, depending on the melting point of the solder powder and the temperature at which BGA warpage occurs. Specifically, the temperature rise rate from the room temperature to 130 ℃ can be set to, for example, 2.1 to 3.9 ℃/sec. In addition, the temperature rise rate of 130-190 ℃ can be set to 0.7-1.3 ℃/sec, for example, and the peak temperature is set to 160-240 ℃. It is also conceivable to heat by local heating without using a reflow furnace, and the temperature increase rate may be, for example, 3.5 to 6.0 ℃/sec in the local heating.

< evaluation experiment of melting Property >

A solder paste was produced using the fluxes of the examples and the comparative examples, using the opening diameter on the substrate (Cu-OSP treated glass epoxy substrate): 0.28mm, mask thickness 0.1mm, number of openings: 64 metal masks to print solder paste. After the printing, the temperature rise rate of 50-170 ℃ is set to 4 ℃/s, the temperature rise rate of 170-195 ℃ is set to about 0.2 ℃/s, the temperature rise rate is set to 118 s, and the peak temperature: 236.5 ℃, melting time above 220 ℃: the reflow temperature profile of 43 seconds was subjected to atmospheric reflow to melt the solder alloy. In the evaluation of the meltability, 64 spots after printing were all melted and evaluated as "o", and even if one spot was not melted, it was evaluated as "x".

The above-described evaluation test of meltability is an example, and the conditions of the evaluation test of meltability are not limited thereto. The heating conditions in the evaluation test of melting property may be changed depending on the melting point of the solder powder, for example. Specifically, the temperature rise rate of 50 to 170 ℃ can be set to, for example, 2.8 to 5.2 ℃/sec. In addition, the temperature rise rate of 170-195 ℃ can be set to 0.14-0.26 ℃/sec, for example, and the peak temperature can be set to 180-280 ℃. It is also conceivable to heat by local heating without using a reflow furnace, and the temperature increase rate may be, for example, 3.5 to 6.0 ℃/sec in the local heating.

< evaluation test of stability with time >

For each solder paste, a paste manufactured by MALCOM corporation was used: PCU-205, according to the JISZ3284-3 screw method, in revolutions: the viscosity was measured at 10rpm for 10 hours at 25 ℃ in the air. Then, the viscosity after 10 hours was compared with the initial viscosity of the solder paste, and when it was 1.3 times or less, it was evaluated as "o" indicating that the paste had sufficient stability over time, and when it exceeded 1.3 times, it was evaluated as "x". The initial viscosity refers to the viscosity at the start of continuous stirring.

< evaluation test of thermal slump >

Each solder paste was measured according to JIS 3284-3. In addition, as for the metal mask, in fig. 6 of JISZ3284-3, a metal mask with a smaller aperture is used. The measurement results were evaluated as "O" when the thickness was 0.4mm or less and "X" when the thickness was 0.5mm or more.

< test for evaluating tackiness >

Each solder paste was measured according to JIS 3284-3. When the average force required for peeling the probe was 1.1N or more, the evaluation was "O", and when the average force was less than 1.1N, the evaluation was "X".

Table 1 shows the evaluation results of the amount of residue and the reflow property of each of the examples and the comparative examples. As is clear from table 1, when the solder paste of comparative example 1 was used, the NWO evaluation value of the joint portion was 35, whereas when the solder pastes of examples 1 to 10 were used, the NWO evaluation value of the joint portion was 20 or less, and occurrence of poor joint was suppressed. In addition, the solder pastes of examples 3 to 10 have an NWO evaluation value of 9 or less, and the occurrence of poor bonding is more effectively suppressed. Further, the solder pastes of examples 5 to 10 have an NWO evaluation value of 5 or less, and the occurrence of poor bonding is almost completely suppressed. From the results, it is found that the addition of 5 to 25 mass% of the compound of the formula (11) based on the entire mass of the flux more effectively suppresses the occurrence of poor bonding. Further, the addition of the compound of the formula (11) in an amount of 10 mass% or more or 11 mass% or more based on the entire mass of the flux can further effectively suppress the occurrence of poor bonding, and the addition of 16 mass% or more can almost completely suppress the occurrence of poor bonding. Further, the solder pastes of examples 1 to 9 have better meltability (reflow property) than the solder paste of example 10. Therefore, it is found from the results that by adding 24 mass% or less, specifically 5 to 24 mass% of the compound of the formula (11) to the entire mass of the flux, occurrence of poor bonding can be more effectively suppressed and more excellent meltability can be obtained.

The present invention is explained above with reference to embodiments and examples, but the present invention is not limited by the embodiments and examples. The constitution and details of the present invention may be variously modified within the scope of the present invention as will be understood by those skilled in the art.

The present application claims priority based on japanese application patent application 2020-.

< accompanying notes >

Some or all of the above embodiments and examples may be described in the following attached form, but are not limited thereto.

(attached note 1)

A solder joint failure inhibitor comprising the compound represented by the chemical formula (11),

in the chemical formula (11),

R¹¹and R¹²Each of which is independently a carboxyl group,

(attached note 2)

The solder joint failure inhibitor according to supplementary note 1, wherein the compound represented by chemical formula (11) is the compound represented by chemical formula (12).

(attached note 3)

The solder joint failure inhibitor according to supplementary note 1, wherein the compound represented by chemical formula (11) is the compound represented by chemical formula (13).

(attached note 4)

A flux for a solder paste, the flux comprising a first metal,

comprises matrix resin, an activating agent, a thixotropic agent, a solvent and a poor solder joint inhibitor,

the solder joint failure inhibitor is the solder joint failure inhibitor described in any one of supplementary notes 1 to 3.

(attached note 5)

The flux according to supplementary note 4, wherein the amount of the solder poor-solder-bonding inhibitor is 5 mass% or more and 25 mass% or less based on the entire mass of the flux.

(attached note 6)

The flux according to supplementary note 4, wherein the amount of the solder poor-solder-bonding inhibitor is 10 mass% or more and 25 mass% or less based on the entire mass of the flux.

(attached note 7)

The flux of any one of supplementary notes 4 to 6, further comprising an amine.

(attached note 8)

The flux according to supplementary note 7, wherein the amine is selected from imidazoles.

(attached note 9)

The flux according to any one of supplementary notes 4 to 8, further comprising an antioxidant.

(attached note 10)

A kind of solder paste is provided,

comprises a flux and a solder powder, wherein the flux is a mixture of solder powder and solder powder,

the flux is the flux of any one of supplementary notes 4 to 9.

Possibility of industrial utilization

As described above, according to the present invention, the occurrence of poor solder bonding can be suppressed. Therefore, the present invention can be suitably used for a semiconductor substrate such as a BGA.

Claims

1. A flux for a solder paste, the flux comprising a first metal,

the solder joint failure inhibitor is a solder joint failure inhibitor containing a compound represented by the following chemical formula (11):

[ CHEM 1]

In the chemical formula (11),

R⁹and R¹⁰Each independently is a saturated or unsaturated linear, branched or cyclic alkyl group having 1 to 18 carbon atoms.

R¹¹And R¹²Each of which is independently a carboxyl group,

2. The flux according to claim 1, wherein the compound represented by the chemical formula (11) is a compound represented by the following chemical formula (12)

[ CHEM 12]

3. The flux according to claim 1, wherein the compound represented by the chemical formula (11) is a compound represented by the following chemical formula (13)

[ CHEM 13]

4. The flux according to any one of claims 1 to 3, wherein the amount of the poor solder joint inhibitor is 5% by mass or more and 25% by mass or less with respect to the entire mass of the flux.

5. The flux according to any one of claims 1 to 3, wherein the amount of the poor solder bonding inhibitor is 10 mass% or more and 25 mass% or less with respect to the entire mass of the flux.

6. The flux of any one of claims 1 to 5, further comprising an amine.

7. The flux of claim 6, in which the amine is selected from imidazoles.

8. The flux according to any one of claims 1 to 7, further comprising an antioxidant.

9. A solder paste, wherein

the flux is the flux of any one of claims 1 to 8.