WO2024122214A1 - 半田フラックスおよび電子部品実装基板の製造方法 - Google Patents

半田フラックスおよび電子部品実装基板の製造方法 Download PDF

Info

Publication number
WO2024122214A1
WO2024122214A1 PCT/JP2023/038512 JP2023038512W WO2024122214A1 WO 2024122214 A1 WO2024122214 A1 WO 2024122214A1 JP 2023038512 W JP2023038512 W JP 2023038512W WO 2024122214 A1 WO2024122214 A1 WO 2024122214A1
Authority
WO
WIPO (PCT)
Prior art keywords
solder
flux
solder flux
electronic component
softening point
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2023/038512
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
祐樹 吉岡
忠彦 境
憲 前田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Intellectual Property Management Co Ltd
Original Assignee
Panasonic Intellectual Property Management Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Panasonic Intellectual Property Management Co Ltd filed Critical Panasonic Intellectual Property Management Co Ltd
Priority to JP2024562621A priority Critical patent/JPWO2024122214A1/ja
Publication of WO2024122214A1 publication Critical patent/WO2024122214A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/36—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
    • B23K35/3601—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with inorganic compounds as principal constituents
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistors
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistors electrically connecting electric components or wires to printed circuits
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistors electrically connecting electric components or wires to printed circuits by soldering

Definitions

  • the present invention relates to a method for manufacturing solder flux and electronic component mounting boards.
  • Patent Document 1 discloses "an electronic circuit component mounting system including a component supplying device that supplies electronic circuit components, a target material holding device that holds a mounting target material on which the electronic circuit components are to be mounted, a component holder that holds the electronic circuit components and a lifting device that raises and lowers the component holder, and a mounting device that receives electronic circuit components from the component supplying device by the component holder and mounts them on the mounting target material held by the target material holding device, characterized in that the electronic circuit component mounting system includes a damage detection device that detects damage to an electronic circuit component at least either when the component holder is brought into contact with an electronic circuit component by lowering the component holder by the lifting device or when the electronic circuit component held by the component holder is brought into contact with the mounting target material.”
  • connection parts of the board In order to avoid damage to tiny electronic components, it is thought to be effective to apply flux to the connection parts of the board before placing the electronic components on the board, in order to prevent the electronic components from colliding with the connection parts.
  • flux In order to avoid damage to tiny electronic components, it is thought to be effective to apply flux to the connection parts of the board before placing the electronic components on the board, in order to prevent the electronic components from colliding with the connection parts.
  • an electronic component is placed on a connection part of a board that has been coated with flux, the joint quality between the electronic component and the board after reflow is strongly affected by the flow of flux due to heating. As a result, sufficient joint quality may not be ensured.
  • solder flux used to mount electronic components to connections on a substrate, the solder flux having a softening point greater than 70°C and less than 170°C.
  • Another aspect of the present invention relates to a method for manufacturing a substrate mounted with electronic components, the method including the steps of: (i) placing the solder flux on a connection portion of a substrate; (ii) placing electronic components on the solder flux; and (iii) soldering the electronic components to the connection portion by a reflow process.
  • FIG. 1A and 1B are conceptual diagrams showing examples of poor bonding between an electronic component and a connection portion of a substrate.
  • 1A to 1C are process diagrams illustrating an example of a manufacturing method according to the first embodiment.
  • FIG. 2 is a schematic diagram for explaining a test method in the examples.
  • solder flux solder flux
  • Figure 1 conceptually shows the process of creating an example of poor bonding between a component and a connection when a component is placed on a connection part of a substrate to which flux has been applied.
  • the connection part of the substrate 1 is composed of a land 2a formed on the substrate 1 and a solder precoat 2b formed in advance on the land 2a.
  • flux 3 is applied to the solder precoat 2b to reduce the impact on the electronic component 4 when mounted and to temporarily fix the electronic component 4 in place.
  • the fluidity of the flux 3 is not controlled, the sinking of the component 4 may be insufficient, and the reflow process may end without the component electrode 4a coming into contact with the solder precoat 2b. This results in a poor connection between the connection and the component 4 (Fig. 1 (e1)). Furthermore, if only one side of the component electrode 4a becomes wet with solder due to the mounting position of the component 4 or various other factors, a defect occurs in which one side of the component 4 floats up (Fig. 1 (e2)). Furthermore, although not shown, if the fluidity of the flux 3 is too high, the component 4 may be washed away from the land 2a along with the flux, or a bridge may occur where the components come into contact with each other.
  • the lower the consistency of the solder flux the greater the tendency for the distance between the component 4 and the solder precoat 2b to increase when the component 4 is placed on the solder precoat 2b via the flux 3. In that case, poor bonding between the connection and the component 4 or poor lifting of the component 4 is more likely to occur.
  • solder precoat is formed using cream solder, it is common to wash the solder precoat after formation to remove any flux residue. However, development of a method that omits the washing step is also underway. When washing is omitted, at least a portion of the solder precoat is covered with a resin film (i.e., flux residue). As the resin film acts as a flux, the distance between the component 4 and the solder precoat 2b tends to increase.
  • a resin film i.e., flux residue
  • solder flux is a solder flux used for mounting electronic components on a substrate (specifically, a connection portion of the substrate).
  • solder flux according to the present embodiment may be referred to as "flux (F)".
  • the softening point of the flux (F) is higher than 70°C and lower than 170°C.
  • solder flux begins to soften before the solder melts, and then its fluidity gradually increases. It is also desirable for the flux to be fluid enough to spread over the solder before the solder melts.
  • the micro-components are strongly affected by the flow of the flux, and sometimes even flow off the connection along with the flux. Conversely, even if the flux remains on the connection, small, lightweight micro-components cannot sink into the flux under their own weight, resulting in poor connections or floating up.
  • the melting point of solder is usually 220°C or higher, and it melts after the flux softens.
  • the flux (F) since the flux (F) has a softening point higher than 70°C, it does not soften and flow excessively before the solder melts, and most of it can remain on the connection. Also, since the flux (F) has a softening point lower than 170°C and softens sufficiently before the solder melts, even small and light micro-components can sink into the flux, which has sufficient fluidity, under their own weight and come into contact with the solder precoat. This significantly reduces connection failures and floating. From the viewpoint of ensuring higher connection reliability, the softening point of the flux (F) is preferably 80°C or higher, and more preferably 100°C or higher. Also, the softening point of the flux (F) is preferably 160°C or lower.
  • the softening point of the flux can be determined, for example, by differential scanning calorimetry (DSC) of the flux.
  • DSC differential scanning calorimetry
  • the inflection point of the endothermic curve obtained by DSC measurement is taken as the softening point.
  • the softening point may be the temperature at the peak top of the differential curve (DDSC) of the DSC curve.
  • DDSC differential curve
  • a DSC600 manufactured by Hitachi High-Tech Science Corporation may be used as a measuring device.
  • the softening point of the flux may be measured using the ring and ball method in accordance with JIS K5902.
  • the softening point of the flux can be controlled by the constituent materials of the flux.
  • the flux may contain a base resin and a thixotropic agent.
  • the softening point Td1 of the base resin is higher than 70°C and lower than 170°C.
  • Td1 is desirably 80°C or higher, and more desirably 100°C or higher.
  • Td1 is desirably 160°C or lower.
  • the softening point Td2 of the thixotropic agent is preferably higher than 50°C and lower than 170°C.
  • Td2 is preferably 60°C or higher, and more preferably 80°C or higher.
  • Td1 is preferably 160°C or lower.
  • the consistency of the flux (F) is preferably 400 or less. If the consistency of the flux (F) is 400 or less, the shock applied to the component when it is mounted on the connection part of the board can be more significantly mitigated. It is more preferable that the consistency of the flux (F) is in the range of 220 to 395.
  • the consistency of solder flux is a value (worked consistency) measured according to the procedure for the worked consistency test specified in JIS K2220:2013. Note that the measurement is performed using a 1/2 cone, and the measured consistency may be converted to the consistency when using a standard cone in accordance with the above JIS standard. The converted consistency may then be used as the consistency of the solder flux.
  • the consistency of the flux (F) may be 240 or more, 285 or more, or 320 or more.
  • the consistency may be 375 or less, 320 or less, or 285 or less.
  • the consistency may be in the range of 240 to 395, 285 to 395, or 320 to 395.
  • the upper limit may be 375, 320, or 285, as long as the lower limit is not equal to or greater than the upper limit.
  • the viscosity of the flux (F) at 25°C is, for example, 70 Pa ⁇ s to 230 Pa ⁇ s, and may be 70 Pa ⁇ s to 170 Pa ⁇ s. Although there is no direct relationship between consistency and viscosity, increasing the viscosity tends to decrease the consistency. By setting the consistency to 400 or less and the viscosity within the above range, the handling properties (particularly the applicability) of the flux (F) are improved.
  • the viscosity can be measured at a temperature of 25°C using a commercially available rheometer.
  • a commercially available rheometer For example, the MCR series (MCR501, etc.) manufactured by Anton Paar can be used as the measuring device.
  • the cone used for the measurement can be a CP25-2 (diameter: 24.977 mm, angle: 1.993°).
  • the softening point of solder flux can be adjusted by the type and ratio of its constituent components. Generally, if the softening point of the base resin and the softening point of the thixotropic agent in the solder flux are high, the softening point of the solder flux tends to be high. Also, generally, if the solvent content is high, the softening point tends to be low. The softening point can be achieved by adjusting the type of base resin, the type and content of the thixotropic agent, and/or the solvent content.
  • the flux (F) contains, for example, a base resin and a thixotropic agent as essential components, and may contain an activator and a solvent as optional components.
  • a rosin-based resin is preferably used as the base resin.
  • the flux (F) may be prepared by mixing these components.
  • a typical flux (F) contains a base resin, a thixotropic agent, an activator, and a solvent.
  • An example of the base resin is a rosin-based resin.
  • the flux (F) may satisfy the following conditions (1) and/or (2): By satisfying the following conditions (1) and (2), it becomes easier to set the softening point within the above range.
  • the content of the thixotropy-imparting agent in the flux (F) is in the range of 1 to 20% by mass (for example, in the range of 3 to 15% by mass or in the range of 3 to 14% by mass).
  • the content of the solvent in the flux (F) is in the range of 10 to 45 mass % (for example, in the range of 15 to 40 mass % or in the range of 18 to 30 mass %).
  • the flux (F) may satisfy the following conditions (3) and/or (4).
  • the flux (F) may satisfy the above conditions (1) and (2) and also satisfy the following conditions (3) and/or (4).
  • the content of the base resin (e.g., rosin resin) in the flux (F) is in the range of 50 to 80% by mass (e.g., in the range of 55 to 80% by mass or in the range of 56 to 76% by mass).
  • the content of the activator in the flux (F) is in the range of 1 to 10 mass % (for example, in the range of 1 to 5 mass %).
  • a rosin-based resin that has reducing properties by itself is preferably used, but resins other than rosin-based resins can also be used.
  • the base resin may be used alone or in a mixture or combination of two or more.
  • rosin-based resins, acrylic resins, polyethylene glycol, etc. are preferable, but are not limited thereto.
  • rosin-based resins examples include natural rosins such as gum rosin and wood rosin, and their derivatives (polymerized rosin, hydrogenated rosin, disproportionated rosin, acid-modified rosin, rosin esters, etc.).
  • resins other than rosin-based resins examples include organic fatty acid esters, polyalkylene oxide-based resins, propylene glycol fatty acid esters, and acetylene glycols.
  • organic fatty acid polyglycerol esters such as polyglycerol laurate, polyglycerol stearate, polyglycerol isostearate, polyglycerol sesquistearate, polyglycerol diisostearate, polyglycerol myristate, polyglycerol palmitate, polyglycerol oleate, polyglycerol behenate, and polyglycerol caprylate, polyethylene glycol, polyethylene glycol-polypropylene glycol copolymer, polyoxyethylene alkyl ester, polyoxyethylene tallow ester, polyglycerin, glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty
  • rosin-based resins include terpene resins, terpene phenolic resins, styrene resins, xylene resins, acrylic resins, polyester resins, polyolefin resins, polyamides, polyamines, phenolic resins, phenoxy resins, epoxy resins, etc.
  • Terpene resins include aromatic modified terpene resins, hydrogenated terpene resins, hydrogenated aromatic modified terpene resins, etc.
  • Terpene phenolic resins include hydrogenated terpene phenolic resins, etc.
  • Styrene resins include styrene-acrylic acid copolymers, styrene-maleic acid copolymers, etc.
  • Xylene resins include phenol modified xylene resins, alkylphenol modified xylene resins, phenol modified resol type xylene resins, polyol modified xylene resins, polyoxyethylene added xylene resins, etc.
  • acrylic resins include acrylic acid, methacrylic acid, various esters of acrylic acid, various esters of methacrylic acid, crotonic acid, itaconic acid, maleic acid, maleic anhydride, esters of maleic acid, esters of maleic anhydride, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, acrylic resins obtained by copolymerizing at least one monomer selected from vinyl chloride and vinyl acetate.
  • polyolefin resins include polyethylene and polypropylene.
  • epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, and bisphenol AD type epoxy resins.
  • thixotropy imparting agent examples include wax-based thixotropy-imparting agents, amide-based thixotropy-imparting agents, sorbitol-based thixotropy-imparting agents, etc.
  • wax-based thixotropy-imparting agent examples include hardened castor oil.
  • amide-based thixotropy-imparting agent examples 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-toluenemethane amide, aromatic amide, methylene bisstearic acid amide, ethylene bislauric acid amide, ethylene bishydroxystearic acid amide, saturated fatty acid bisamide, methylene bisoleic acid amide, unsaturated fatty acid bisamide, m-xylylene bisstearic acid amide, aromatic bisamide, saturated fatty acid polyamide, unsaturated fatty acid polyamide, aromatic polyamide, substituted amide, methylol stearic acid amide, methylol amide, and fatty acid ester amide.
  • sorbitol-based thixotropy-imparting agents examples include dibenzylidene-D-sorbitol, bis(4-methylbenzylidene)-D-sorbitol, etc.
  • the thixotropy-imparting agents may be used alone or in combination of two or more.
  • the activator is a compound that reduces the oxide film that covers the surface of the solder used in soldering electronic components.
  • the solder include solder precoat and solder applied to the terminals (component electrodes) of electronic components, as described above.
  • base resins such as rosin-based resins may also have a certain degree of activating effect.
  • the activator described here means a compound other than base resins such as rosin-based resins.
  • the activator reduces the oxide film and helps to form a good joint.
  • Examples of activators with a reducing effect include organic acids, amines, and halides.
  • the activators may be used alone or in combination of two or more.
  • Organic acids used as activators include, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dimer acid, propionic acid, 2,2-bishydroxymethylpropionic acid, tartaric acid, malic acid, glycolic acid, diglycolic acid, thioglycolic acid, dithioglycolic acid, stearic acid, 12-hydroxystearic acid, palmitic acid, and oleic acid.
  • Amines used as activators include, for example, ethylamine, triethylamine, ethylenediamine, triethylenetetramine, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyano
  • Halides used as activators include amine hydrohalides, organic halogen compounds, etc.
  • Amines constituting amine hydrohalides include, for example, ethylamine, ethylenediamine, triethylamine, diphenylguanidine, ditolylguanidine, methylimidazole, 2-ethyl-4-methylimidazole, etc.
  • hydrogen halides include, for example, hydrogen chloride, hydrogen bromide, hydrogen iodide, etc.
  • organic halogen compounds include trans-2,3-dibromo-2-butene-1,4-diol, triallyl 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-propanol, 2,3-dibromo-1-propanol, 2,3-dibromo-1,4-butanediol, and 2,3-dibromo-2-butene-1,4-diol.
  • solvent examples include water, alcohol-based solvents, glycol-based solvents, ketone-based solvents, hydrocarbon-based solvents, ester-based solvents, glycol ether-based solvents, terpineols, etc.
  • the solvent may be used alone or in combination of two or more.
  • alcohol-based solvents 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'-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
  • glycol solvents include ethylene glycol monomethyl ether, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, triethylene glycol monobutyl ether, diethylene glycol monohexyl ether (hexyl carbitol), diethylene glycol mono 2-ethylhexyl ether, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monobenzyl ether, diethylene glycol dibutyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monobutyl ether, propylene glycol monophenyl ether, diethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, 2-methylpentane-2,4-diol, and triethylene glycol monobutyl ether.
  • Ketone solvents include, for example, methyl ethyl ketone, methyl-n-propyl ketone, diethyl ketone, cyclohexanone, etc.
  • hydrocarbon solvents examples include normal hexane, isohexane, cyclohexane, methylcyclohexane, ethylcyclohexane, normal heptane, isoheptane, normal octane, isooctane, limonene, 2-methyl-2-butene, 2-methyl-1-pentene, 2-methyl-2-pentene, 3-ethyl-2-butene, 2,3-dimethyl-2-butene, 2,4,4-trimethyl-1-pentene, and 2,4,4-trimethyl-2-pentene.
  • ester-based solvents examples include butyl stearate, 2-ethylhexyl stearate, isotridecyl stearate, methyl oleate, isobutyl oleate, methyl coconut fatty acid, methyl laurate, isopropyl myristate, isopropyl palmitate, 2-ethylhexyl palmitate, and octyldodecyl myristate.
  • the flux (F) may contain other components in addition to the components described above.
  • examples of other components include surfactants, silane coupling agents, antioxidants, colorants, etc.
  • the electronic components mounted on the connection part may be electronic components of various sizes.
  • the electronic components may be electronic components of JIS (Japanese Industrial Standards) size 0402 or less (e.g., electronic components such as 0603, 0402, 0201, 03015, 01005, etc.).
  • the electronic components may be electronic components of JIS size 0201 or less. The smaller the electronic components are, the smaller the breaking strength of the electronic components and the smaller the limit load.
  • the 0402 size is 0.4 mm x 0.2 mm (length x width).
  • the 0201 size is 0.25 mm x 0.125 mm (length x width).
  • the breaking strength of an electronic component is, for example, 170 MPa or less, and may be 100 MPa to 170 MPa.
  • the breaking strength is the load at which the electronic component breaks when the load is gradually increased by pressing the electronic component with an indenter.
  • the breaking strength of an electronic component can be measured using a commercially available micro-compression tester (for example, MCT-W500 manufactured by Shimadzu Corporation). For example, a flat indenter with a tip diameter of 50 ⁇ m is used, and the breaking strength of 10 electronic components is measured at a displacement speed of 5 ⁇ m/sec, and the average value is calculated.
  • Step (i) is a step of placing flux (F) on the connection parts of the board.
  • the method of placing the flux (F) there is no particular limitation on the method of placing the flux (F), and any known application method may be used.
  • a screen printing method, a dispensing method, a spraying method, etc. may be used.
  • the screen printing method is preferable in that a layer of flux (F) with a uniform thickness can be formed on multiple connection parts at once.
  • connection portion may include a land and a solder precoat formed on the land.
  • flux (F) may be placed on the solder precoat.
  • solder precoats are formed using cream solder, they are generally washed to remove any residual flux after formation, but methods that omit the washing step are also being developed. In such cases, at least a portion of the solder precoat may be covered with a resin film (i.e., flux residue). The resin film, together with the flux applied to the solder precoat, softens when heated.
  • a resin film i.e., flux residue
  • Step (ii) is a step of placing electronic components on the flux (F) placed in step (i).
  • step (ii) typically, multiple electronic components are placed on the flux (F) on multiple connection portions.
  • the board includes connection portions corresponding to the multiple electronic components.
  • the electronic components may be electronic components of the above-mentioned sizes.
  • the electronic components may include electronic components of JIS size 0402 or smaller. That is, at least one electronic component may be 0402 size or smaller.
  • the method for placing electronic components there are no particular limitations on the method for placing electronic components, and known mounting devices may be used. Normally, when placing components with a low limit load, the operating speed of the nozzle for placing the components is slower than when placing components with a relatively high limit load. However, in manufacturing method (M), the impact on the electronic components can be largely mitigated by the layer of flux (F), so there is no need to significantly slow down the operating speed of the nozzle. Alternatively, the nozzle may be moved at the same speed as when placing normal components to place the components.
  • the electronic component may include terminals to which solder has been applied. By soldering the electronic component using solder that has already been applied, it may be easier to solder tiny electronic components accurately.
  • Step (iii) is a step of soldering the electronic components to the connection parts by a reflow process.
  • the reflow process There is no particular limitation on the reflow process, and any known reflow process may be used.
  • the substrate on which the electronic components are arranged in step (ii) is heated to a temperature equal to or higher than the temperature at which the solder melts, thereby melting the solder, and then the substrate is cooled to solidify the solder.
  • the solder that melts and solidifies is the solder contained in the connection parts of the substrate and/or the solder applied to the terminals of the electronic components.
  • any known solder used in reflow soldering may be used.
  • solder contained in the connection parts of the substrate includes a solder precoat.
  • the solder contained in the connection parts of the substrate may be a solder precoat formed on a land of the substrate. In that case, the electronic components are soldered to the land.
  • the substrate examples include substrates such as laminate substrates, resin substrates, ceramic substrates, and silicon substrates, semiconductor elements, and semiconductor packages.
  • the substrate may be a structure including various substrates and a semiconductor package mounted on the substrate. Examples of such structures include chip-on-board, chip-on-film, chip-on-glass, chip-on-chip, chip-on-package, and package-on-package.
  • the substrate there are no particular limitations on the substrate, and it may be a laminate substrate, a resin substrate, a ceramic substrate, a silicon substrate, or the like.
  • An example of a substrate on which a connection portion is formed is a printed circuit board.
  • the electronic components mounted on the substrate include surface-mounted components such as resistor elements, semiconductor elements, capacitors, coils, chip components, connectors, semiconductor packages, and module components.
  • connection part of the board is the part where the electronic component is soldered.
  • connection part include wiring, such as the printed wiring of a printed circuit board.
  • solder precoat there are no particular limitations on the method of forming the solder precoat, and the solder precoat may be formed by a known method. Alternatively, a commercially available board on which a solder precoat has been formed may be used.
  • connection portion 2 includes a land 2a and a solder precoat 2b formed on the land 2a.
  • the substrate 1 on which the connection portion 2 is formed is referred to as a substrate 10.
  • a mask pattern 101 is placed on the substrate 1.
  • the mask pattern 101 has an opening 101a in the area where the solder flux is to be placed.
  • solder flux 3 is placed on the connection portion 2 by screen printing.
  • the solder flux 3 is the solder flux (F) described above.
  • the solder flux 3 is placed on the solder precoat 2b.
  • the illustrated example electronic component 4 includes two terminals (component electrodes) 4a and an element portion 4b placed between them.
  • the number of terminals of the electronic component varies depending on the type of electronic component.
  • flux (F) is used, so damage to the electronic components can be suppressed when the electronic components are placed.
  • the electronic component 4 is soldered to the connection portion 2 (land 2a) by the solder 5.
  • the flux (F) is used, so the flux (F) does not soften excessively and flow before the solder melts, and most of it can remain on the connection portion of the board.
  • the flux (F) has a softening point lower than 170°C and softens sufficiently before the solder melts, so even small and light micro-components can sink into the softened flux (F) and come into contact with the solder precoat. Therefore, poor connection and floating are significantly suppressed. In this way, an electronic component mounting board 1x on which multiple electronic components 4 are mounted is obtained.
  • the above description discloses the following techniques.
  • (Technique 1) A solder flux used for mounting electronic components to connection portions of a substrate, A solder flux having a softening point higher than 70°C and lower than 170°C.
  • (Technique 2) The composition includes a base resin and a thixotropic agent, The base resin has a softening point Td1, The solder flux according to claim 1, wherein the softening point Td1 is higher than 70°C and lower than 170°C.
  • (Technique 3) The thixotropic agent has a softening point Td2, The solder flux according to claim 2, wherein the softening point Td2 is higher than 50°C and lower than 170°C.
  • (Technique 10) A method for manufacturing an electronic component mounting board, comprising: (i) placing the solder flux according to claim 1 on a connection portion of a substrate; (ii) placing an electronic component on the solder flux; (iii) soldering the electronic component to the connection portion by a reflow process; A method for manufacturing an electronic component mounting board, comprising: (Technique 11) The connection portion includes a land and a solder precoat formed on the land, In the step (i), the solder flux is placed on the solder precoat; The manufacturing method according to technique 10, wherein in the step (iii), the electronic component is soldered to the land. (Technique 12) 12. The manufacturing method according to claim 10 or 11, wherein the electronic component includes a terminal to which solder is applied. (Technique 13) 13. The manufacturing method according to claim 11, wherein at least a part of the solder precoat is covered with a resin film.
  • Example 1 First, the components constituting the solder flux were prepared. Specifically, a rosin-based resin, a thixotropic agent, a solvent, and additives as necessary were prepared. Polymerized rosin (softening point 96°C) was used as the rosin-based resin. Hardened castor oil (softening point 83°C) was used as the thixotropic agent. Diethylene glycol monohexyl ether was used as the solvent.
  • Polymerized rosin softening point 96°C
  • Hardened castor oil softening point 83°C
  • Diethylene glycol monohexyl ether was used as the solvent.
  • Solder fluxes A1 to A6 and C1 were prepared by mixing the above components in the amounts shown in Table 1. The softening point, consistency and viscosity at 25°C of the resulting solder flux and solder flux C2 were measured using the methods described above.
  • solder flux 3 was applied onto a glass plate 200. Then, an electronic component 4 was placed on the solder flux 3. Next, a predetermined load (the mounting load shown in Table 1) was applied to the electronic component 4 from above using a pressing member 210 for approximately two seconds. Ten electronic components 4 were tested for each solder flux 3. This test was conducted for each of the four types of electronic components with different sizes shown in Table 1.
  • the mounting load was changed depending on the size of the electronic component being tested. Specifically, the mounting load shown in parentheses in Table 1 was applied for approximately 2 seconds. For example, in testing 0201 size electronic components, a load of 5N was applied for approximately 2 seconds. The mounting load applied was the limit load (load at which damage may occur) for each size of electronic component being tested.
  • Example 2 Fluxes A101 to A315, A501 to A615, and C101 to C115 were prepared in the same manner as solder fluxes A1 to A3, A5 to A6, and C1, except that the softening point of the rosin-based resin in each composition was changed as shown in Table 2.
  • the softening points of the fluxes were the same as the softening point of the base resin (rosin-based resin).
  • the prepared solder flux was used to carry out a test of mounting electronic components on a board. Specifically, a solder precoat was formed on the land of a board designed to mount 100 0603 components with a distance of 0.1 mm between adjacent components, and flux was applied to the solder precoat by screen printing. Furthermore, 100 components were mounted on the flux using a component mounting device. However, the mounting tact of the component mounting device was controlled so that the impact when mounting the components was reduced. After that, the component electrodes and lands were bonded using a normal reflow profile (preheat conditions: 130°C to 180°C/90 seconds, peak temperature: 230°C to 245°C), and the presence or absence of bonding defects was evaluated.
  • Example 3 Fluxes A116 to A330, A516 to A630, and C116 to C130 were prepared in the same manner as solder fluxes A1 to A3, A5 to A6, and C1, except that the softening point of the thixotropy-imparting agent in each composition was changed as shown in Table 3.
  • the prepared solder flux was used to carry out a test to mount electronic components on a substrate in the same manner as in Example 2.
  • the evaluation results are shown in Table 3.
  • Solder fluxes A1 to A5, A101 to A315 (No. 3 to No. 11), A501 to A615 (No. 3 to No. 11), A116 to A330 (No. 18 to No. 26), and A516 to A630 (No. 18 to No. 26) are fluxes (F) according to this disclosure.
  • Solder fluxes C1-C2, A101-A315 (No. 1, 2, 12-14), A501-A615 (No. 1, 2, 12-14), A116-A330 (No. 16, 17, 27-30), A516-A630 (No. 16, 17, 27-30), and C101-C130 are comparative example fluxes.
  • Solder flux C2 is a commercially available product, and the others were prepared by mixing the ingredients in the ratios shown in Tables 1 to 3. The consistency of solder flux C2 was 475 or more, but the exact value could not be measured.
  • Example 3 the softening point of the flux was the same as the softening point of the base resin (rosin-based resin) (96°C), but when the thixotropic agent had a softening point lower than 96°C, a small amount of flow occurred at that softening point. However, at that point, the sinking of the parts was insufficient, and sufficient sinking of the parts occurred at the softening point of the base resin.
  • This disclosure can be used in manufacturing methods for solder flux and electronic component mounting boards.
  • Substrate 1x Electronic component mounting substrate 2: Connection portion 2a: Land 2b: Solder precoat 3: Solder flux 4: Electronic component 4a: Terminal (component electrode) 5: Solder

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Electric Connection Of Electric Components To Printed Circuits (AREA)
PCT/JP2023/038512 2022-12-06 2023-10-25 半田フラックスおよび電子部品実装基板の製造方法 Ceased WO2024122214A1 (ja)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2024562621A JPWO2024122214A1 (https=) 2022-12-06 2023-10-25

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022195026 2022-12-06
JP2022-195026 2022-12-06

Publications (1)

Publication Number Publication Date
WO2024122214A1 true WO2024122214A1 (ja) 2024-06-13

Family

ID=91378893

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/038512 Ceased WO2024122214A1 (ja) 2022-12-06 2023-10-25 半田フラックスおよび電子部品実装基板の製造方法

Country Status (2)

Country Link
JP (1) JPWO2024122214A1 (https=)
WO (1) WO2024122214A1 (https=)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08250848A (ja) * 1995-03-07 1996-09-27 Matsushita Electric Ind Co Ltd チップの半田付け方法
JPH09321425A (ja) * 1996-05-28 1997-12-12 Nippon Antomu Kogyo Kk チップ状電子部品の実装方法
JP2001105180A (ja) * 1999-10-05 2001-04-17 Showa Denko Kk はんだ付けフラックス
JP2001300766A (ja) * 2000-04-27 2001-10-30 Tamura Kaken Co Ltd 回路基板はんだ付用フラックス及び回路基板
JP2002314239A (ja) * 2001-04-10 2002-10-25 Seiko Epson Corp 電子部品の実装方法、マスキング部材及び電気光学装置の製造方法
JP2007207868A (ja) * 2006-01-31 2007-08-16 Toshiba Corp 配線基板
JP2009094251A (ja) * 2007-10-05 2009-04-30 Sharp Corp プリント基板用印刷マスクおよびその印刷マスクを使用したプリント基板の実装方法
WO2022209001A1 (ja) * 2021-03-31 2022-10-06 千住金属工業株式会社 フラックスコートはんだプリフォーム用フラックス、フラックスコートはんだプリフォーム、及び電子基板に電子部品を実装する方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9073153B2 (en) * 2010-02-09 2015-07-07 Nordson Corporation Flux and solder material and method of making same
JP6413843B2 (ja) * 2015-02-27 2018-10-31 住友金属鉱山株式会社 はんだ用フラックスおよびはんだペースト
US12484157B2 (en) * 2021-03-18 2025-11-25 Panasonic Intellectual Property Management Co., Ltd. Adhesive for provisionally fixing electronic component to solder precoat and method for producing electronic component mounted substrate

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08250848A (ja) * 1995-03-07 1996-09-27 Matsushita Electric Ind Co Ltd チップの半田付け方法
JPH09321425A (ja) * 1996-05-28 1997-12-12 Nippon Antomu Kogyo Kk チップ状電子部品の実装方法
JP2001105180A (ja) * 1999-10-05 2001-04-17 Showa Denko Kk はんだ付けフラックス
JP2001300766A (ja) * 2000-04-27 2001-10-30 Tamura Kaken Co Ltd 回路基板はんだ付用フラックス及び回路基板
JP2002314239A (ja) * 2001-04-10 2002-10-25 Seiko Epson Corp 電子部品の実装方法、マスキング部材及び電気光学装置の製造方法
JP2007207868A (ja) * 2006-01-31 2007-08-16 Toshiba Corp 配線基板
JP2009094251A (ja) * 2007-10-05 2009-04-30 Sharp Corp プリント基板用印刷マスクおよびその印刷マスクを使用したプリント基板の実装方法
WO2022209001A1 (ja) * 2021-03-31 2022-10-06 千住金属工業株式会社 フラックスコートはんだプリフォーム用フラックス、フラックスコートはんだプリフォーム、及び電子基板に電子部品を実装する方法

Also Published As

Publication number Publication date
JPWO2024122214A1 (https=) 2024-06-13

Similar Documents

Publication Publication Date Title
JP7133579B2 (ja) はんだ組成物および電子基板
KR101678749B1 (ko) 리플로우 필름, 땜납 범프 형성 방법, 땜납 접합의 형성 방법 및 반도체 장치
CN100528461C (zh) 一种用于锡铅焊膏的无松香免清洗助焊剂及其制备方法
JP5242521B2 (ja) はんだ接合剤組成物
US10906137B2 (en) Solder composition and electronic board
CN103289621A (zh) 热固性树脂组合物
JP7312798B2 (ja) はんだ組成物
JP6346757B2 (ja) プリント配線基板の製造方法
JP6864046B2 (ja) ジェットディスペンサー用はんだ組成物、および電子基板の製造方法
US12484157B2 (en) Adhesive for provisionally fixing electronic component to solder precoat and method for producing electronic component mounted substrate
TWI750060B (zh) 助焊劑組成物、及使用其之焊膏
JP2015047616A (ja) ジェットディスペンサー用はんだ組成物
TW201932226A (zh) 助焊劑及焊膏
EP3040154B1 (en) Cleaning flux, cleaning solder paste, and use to form a solder joint
JP2023163663A (ja) 半田フラックスおよび電子部品実装基板の製造方法
US8070047B1 (en) Flux composition and method of soldering
CN113453445A (zh) 激光焊接用焊料组合物、电子基板、以及电子基板的制造方法
JP2022188686A (ja) フラックス組成物、およびはんだ組成物、並びに、電子基板の製造方法
WO2024122214A1 (ja) 半田フラックスおよび電子部品実装基板の製造方法
JP6222415B1 (ja) フラックス
JP2015208779A (ja) はんだ用フラックスおよびはんだペースト
TW202418301A (zh) 導電膏及連接構造體
JP2024081424A (ja) 半田フラックスおよび電子部品実装基板の製造方法
JP5635561B2 (ja) はんだ組成物
WO2026048396A1 (ja) 電子部品実装基板の製造方法、半田ペーストとフラックスとのセット、およびフラックス

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23900336

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2024562621

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 23900336

Country of ref document: EP

Kind code of ref document: A1