JP7804808B2 - Cleaning method for tin-containing water-soluble flux - Google Patents

Description

This disclosure relates to a method for cleaning tin-containing water-soluble flux and a tin deposition inhibitor.

To reduce manufacturing costs, metals such as copper and copper alloys are used for the electrodes that form the circuits of electronic substrates such as semiconductor packages.

Surface mounting, which improves mounting density, is widely used as a mounting method for printed wiring boards. One known technique for improving mounting density involves applying a nanometal paste between the wiring on the board and the terminals of the electronic element, then melting and solidifying the nanometal by heating, thereby bonding the wiring on the board and the terminals of the electronic element.

On the other hand, there is known a technique for cleaning solder flux and resist from electronic components after soldering.
For example, Patent Document 1 proposes a dual-purpose cleaner capable of simultaneously cleaning solder flux and dry film resist, characterized in that the amounts of benzyl alcohol added are 5 to 94 wt %, amine compound is 1 to 50 wt %, and water is 3 to 90 wt % relative to the total weight.
Patent Document 2 proposes a cleaning agent for lead-free solder water-soluble flux, which contains 5 to 100 parts by weight of a glycol ether compound per 100 parts by weight of water.
Patent Document 3 proposes a cleaning composition for a resin mask layer, which contains, per 100 parts by mass of the cleaning composition, 0.5 to 3.0 parts by mass of a specific quaternary ammonium hydroxide, 3.0 to 10.0 parts by mass of a water-soluble amine, 0.3 to 2.5 parts by mass of an acid or an ammonium salt thereof, and 50.0 to 95.0 parts by mass of water.

Japanese Patent Application Laid-Open No. 2007-224165 International Publication No. 2011/027673 JP 2015-79244 A

It is known that water-soluble flux remaining on electronic components mounted using solder containing tin (Sn) can be easily cleaned (removed) using aqueous cleaners. However, tin from the solder is dissolved and dissolved in the water-soluble flux before cleaning. Therefore, when such water-soluble flux is cleaned and rinsed with water and then dried, the tin dissolved and dissolved in the water-soluble flux may precipitate as insoluble tin compounds (e.g., tin oxides such as SnO and _SnO2 ) (tin reprecipitation). These insoluble tin compounds (tin precipitates) can lead to problems such as reduced insulation resistance and reduced product performance, which can reduce the electrical reliability of electronic components.
Therefore, there is a need for cleaning agents and methods that can suppress the generation and growth of insoluble tin deposits while maintaining the ability to remove water-soluble flux (cleaning performance) when cleaning electronic components mounted using solder containing tin.
The inventors have found that if the solubility of the water-soluble deflux chemical itself in undissolved tin (zerovalent tin) in solder can be suppressed and the solubility of dissolved tin (e.g., divalent or tetravalent tin) can be maintained during cleaning and rinsing, the generation and growth of insoluble tin precipitates can be suppressed.

The present disclosure provides a cleaning method for tin-containing water-soluble flux and a tin precipitate inhibitor using a composition that can suppress the solubility of undissolved tin (zerovalent tin) when cleaning electronic components mounted using tin-containing solder, and that can maintain the solubility of dissolved tin (e.g., divalent or tetravalent tin) during cleaning and rinsing.

In one aspect, the present disclosure relates to a method for cleaning a tin-containing water-soluble flux, the method comprising a cleaning step of treating a substrate having tin-containing water-soluble flux residue with a composition containing an organic solvent (component A), at least one alkali compound (component B) selected from a quaternary ammonium hydroxide and an amine compound, and water (component C), wherein the ratio [II/I] of the following electrical conductivity II to the following electrical conductivity I is in the range of 0.03 or more and 1.0 or less.
Conductivity I: Conductivity of the composition used to treat the substrate in the cleaning step Conductivity II: Conductivity when the composition used to treat the substrate in the cleaning step is diluted 100 times

In one aspect, the present disclosure relates to a tin deposition inhibitor containing an organic solvent (component A), at least one alkali compound selected from quaternary ammonium hydroxides and amine compounds (component B), and water (component C).

In one aspect, the present disclosure relates to a method for manufacturing electronic components, which includes a flux cleaning step using the cleaning method of the present disclosure.

This disclosure provides a cleaning method for tin-containing water-soluble flux and a tin precipitate inhibitor that use a composition that can suppress the solubility of undissolved tin (zerovalent tin) when cleaning electronic components mounted using tin-containing solder, while maintaining the solubility of dissolved tin (e.g., divalent or tetravalent tin) during cleaning and rinsing.

The inventors have discovered that by using a composition containing an organic solvent and an alkaline compound, where the ratio [II/I] of the electrical conductivity I of the composition used in substrate processing to the electrical conductivity II when the composition used in substrate processing is diluted 100 times, falls within a specific range, to process a substrate having tin-containing water-soluble flux residue, the composition can suppress the solubility of undissolved tin (zerovalent tin) and maintain the solubility of dissolved/dissolved tin (e.g., divalent or tetravalent tin) during cleaning and rinsing, thereby suppressing the formation of insoluble tin precipitates while maintaining the ability to remove water-soluble flux.

That is, in one aspect, the present disclosure relates to a method for cleaning a tin-containing water-soluble flux (hereinafter also referred to as the "cleaning method of the present disclosure"), which includes a cleaning step of treating a substrate having tin-containing water-soluble flux residue with a composition (hereinafter also referred to as the "composition of the present disclosure") containing an organic solvent (component A), at least one alkali compound (component B) selected from a quaternary ammonium hydroxide and an amine compound, and water (component C), wherein the ratio [II/I] of the electrical conductivity II below to the electrical conductivity I below is in the range of 0.03 or more and 1.0 or less.
Conductivity I: Conductivity of the composition used to treat the substrate in the cleaning step Conductivity II: Conductivity when the composition used to treat the substrate in the cleaning step is diluted 100 times

In one or more embodiments, the present disclosure provides a cleaning method for a tin-containing water-soluble flux using a composition that can suppress the solubility of undissolved tin (zerovalent tin) and maintain the solubility of dissolved/dissolved tin (e.g., divalent or tetravalent tin) during cleaning and rinsing when cleaning electronic components mounted using tin-containing solder.

Although the details of the mechanism of action by which the effects of the present disclosure are manifested are still unclear, it is speculated as follows.
Tin is used as a main component of solder alloys and is well known to be corroded by strong alkaline liquids. Tin components dissolved in strong alkaline liquids are precursors of insoluble tin precipitates, and it is thought that the formation of insoluble tin precipitates is promoted. From the viewpoint of preventing damage to components, it is preferable that zero-valent tin does not dissolve.
On the other hand, it is known that tin oxide present on the solder surface dissolves/elutes into the water-soluble flux during the process of heating the substrate (cited in JP 2000-042786 A, paragraph 0009). The already dissolved tin ions are also precursors of insoluble tin precipitates, and must remain in the form of tin ions until they are removed from the solder (a period including the cleaning, rinsing, and drying processes for electronic components mounted using tin-containing solder).
In the cleaning method of the present disclosure, a substrate having tin-containing water-soluble flux residue is treated with a composition containing an organic solvent and an alkaline compound, wherein the ratio [II/I] of the electrical conductivity I of the composition used for substrate treatment to the electrical conductivity II when the composition used for substrate treatment is diluted 100 times is within a specific range. This composition suppresses dissolution of zero-valent tin while allowing tin ions generated from tin oxide to remain in the state of tin ions throughout the period including the cleaning step, rinsing step, and drying step, and is therefore considered to be excellent at preventing the generation of insoluble tin precipitates.
However, the present disclosure need not be construed as being limited to this mechanism.

In the present disclosure, "tin-containing water-soluble flux residue" refers to residue derived from water-soluble flux remaining on a substrate after forming solder bumps using the water-soluble flux and/or on a substrate after soldering using the water-soluble flux. For example, when other components (e.g., semiconductor chips, chip-type capacitors, other circuit boards, etc.) are stacked and mounted on a circuit board, a space (gap) is formed between the circuit board and the other components. The water-soluble flux used for the mounting may remain in this gap as flux residue after soldering by reflow or the like.
In one or more embodiments, the "composition" in this disclosure is a cleaning composition for cleaning and removing water-soluble flux residue after forming and/or soldering a solder bump using the water-soluble flux.
The water-soluble flux used in forming and/or soldering the solder bumps (water-soluble flux residue to be cleaned and removed) may contain dissolved tin (e.g., divalent or tetravalent tin) due to the dissolution of tin (zerovalent tin) in the solder.
Examples of tin-containing water-soluble flux residues that can be treated (cleaned) with the composition of the present disclosure include (a) water-soluble flux residues that are generated after soldering with a solder cream made of powdered solder and water-soluble flux, and (b) water-soluble flux residues that are generated after soldering an electrode made of solder via a water-soluble flux.

In this disclosure, in one or more embodiments, "solder" refers to solder containing tin. Examples of solder containing tin include lead (Pb)-free solders containing tin, such as Sn-Ag solder, Sn-Cu solder, Sn-Ag-Cu solder, Sn-Zn solder, and Sn-Sb solder.

In the present disclosure, the term "water-soluble flux" refers to a water-soluble flux that does not contain rosin and is used to remove oxides that interfere with the connection between the metal of an electrode, wiring, etc. and the solder metal, and to promote the connection.
The water-soluble flux may be, for example, a composition containing a resin, an activator, and a solvent as main components.
Examples of resins contained in the water-soluble flux include polyethylene glycol, polypropylene glycol, copolymers thereof, and derivatives thereof; polyglycerin ester compounds; triazine compounds; vinyl group-containing compounds; carboxyl group-containing compounds; and epoxy group-containing compounds.
Examples of the activator contained in the water-soluble flux include halogen compounds, organic acids, amine compounds, amine salts, amino acids, amide compounds, etc. Examples of the amine compounds include monoalkanolamines, dialkanolamines, trialkanolamines, etc.
Examples of the solvent contained in the water-soluble flux include water, aliphatic alcohols, aromatic alcohols, glycols, and polyhydric alcohols.
The water-soluble flux is a flux that dissolves or disperses in water when applied to the substrate before heat treatment such as reflow, and is preferably a water-soluble flux whose solubility in water at 20°C is 1 mass % or more.

[Cleaning process]
The cleaning step included in the cleaning method of the present disclosure is a cleaning step (hereinafter also simply referred to as the "cleaning step") in which a substrate (object to be cleaned) having tin-containing water-soluble flux residue is treated with the composition of the present disclosure.
Here, in one or more embodiments, the term "treatment" includes cleaning the object to be cleaned and removing tin-containing water-soluble residue from the object to be cleaned. In one or more embodiments, the treatment does not include cleaning or removing dry film resist. That is, in one or more embodiments, the cleaning step does not include simultaneously cleaning or removing water-soluble flux (tin-containing water-soluble flux residue) and dry film resist.
According to the cleaning method of the present disclosure, in one or more embodiments, the composition of the present disclosure can suppress the solubility of undissolved tin (zerovalent tin) and can maintain the solubility of dissolved tin (e.g., divalent or tetravalent tin) during cleaning and rinsing, thereby suppressing the formation of insoluble tin precipitates when cleaning electronic components mounted using tin-containing solder. According to the cleaning method of the present disclosure, in one or more embodiments, the formation of insoluble tin precipitates can be suppressed while efficiently cleaning tin-containing water-soluble flux residue remaining in gaps between soldered components.

In one or more embodiments, the cleaning step includes contacting the object to be cleaned with the composition of the present disclosure. In one or more embodiments, "contact" in the present disclosure includes immersing the object to be cleaned in the composition and shower-washing the object to be cleaned with the composition.
Examples of methods for contacting an object to be cleaned with a composition of the present disclosure, treating an object to be cleaned with a composition of the present disclosure, and cleaning an object to be cleaned with a composition of the present disclosure include a method for contacting the object in a bathtub of an ultrasonic cleaning device, a method for contacting the object by spraying the composition in a spray form (shower method), etc. In one or more embodiments, the composition of the present disclosure can be used for treatment or cleaning as is without dilution.

In one or more embodiments, the cleaning step includes immersing the object to be cleaned in the composition of the present disclosure.
The time for which the object to be cleaned is contacted or immersed in the composition of the present disclosure (contact time or immersion time) is preferably 1 minute or longer, more preferably 3 minutes or longer, even more preferably 5 minutes or longer, and preferably 3 hours or shorter, more preferably 2 hours or shorter, and even more preferably 1 hour or shorter, from the viewpoint of improving the removability of tin-containing water-soluble flux. From the same viewpoint, the contact time or immersion time is preferably 1 minute or longer and 3 hours or shorter, more preferably 3 minutes or longer and 2 hours or shorter, and even more preferably 5 minutes or longer and 1 hour or shorter.
The temperature of the composition of the present disclosure that is brought into contact with or immersed in the object to be cleaned (contact temperature or immersion temperature) is preferably 10° C. or higher, more preferably 20° C. or higher, even more preferably 30° C. or higher, and even more preferably 40° C. or higher, from the viewpoint of improving the removability of tin-containing water-soluble flux, and from the viewpoint of suppressing the generation of insoluble tin precipitates, and from the viewpoints of handling safety and reducing the load on the equipment, it is preferably 80° C. or lower, more preferably 70° C. or lower, and even more preferably 60° C. or lower. From the same viewpoint, the contact temperature or immersion temperature is preferably 10° C. or higher and 80° C. or lower, more preferably 20° C. or higher and 70° C. or lower, even more preferably 30° C. or higher and 60° C. or lower, and even more preferably 40° C. or higher and 60° C. or lower.
Therefore, in one or more embodiments, the cleaning step includes contacting or immersing the object to be cleaned in a composition at a temperature of 10°C or higher and 80°C or lower.

In one or more embodiments, the cleaning step includes cleaning a substrate (object to be cleaned) having tin-containing water-soluble flux residue using a cleaning machine. Examples of cleaning machines include immersion cleaners, ultrasonic cleaners, vibration cleaners, spray cleaners, vacuum cleaners, and vacuum ultrasonic cleaners.

In the cleaning method of the present disclosure, it is preferable to irradiate the composition of the present disclosure with ultrasonic waves when it comes into contact with the object to be cleaned, as this makes it easier for the cleaning power of the composition of the present disclosure to be exerted, and it is more preferable that the ultrasonic waves be relatively strong.

In one or more embodiments, the cleaning method of the present disclosure preferably includes, after contacting the object to be cleaned with the composition of the present disclosure (after the cleaning step), a step of rinsing with water and/or an alcohol such as methanol or a halogenated solvent (rinsing step), and a step of drying (drying step).

[Composition]
In one or more embodiments, the composition of the present disclosure used in the cleaning step contains or is blended with the components A, B, and C described below, and may further contain or be blended with optional components (component D, component E, and other components) described below as needed. In the present disclosure, "containing or being blended with components A, B, and C" means that in addition to components A, B, and C, optional components may further be contained or blended as needed.
In one or more embodiments, the composition of the present disclosure used in the cleaning step can be used as a cleaning agent for removing tin-containing water-soluble flux residue from a substrate (object to be cleaned) having the tin-containing water-soluble flux residue. Thus, in one or more embodiments, the composition of the present disclosure is a cleaning agent composition for removing tin-containing water-soluble flux residue.

(Conductivity of Composition)
In the present disclosure, the electrical conductivity I (hereinafter also simply referred to as "electrical conductivity I") of the composition used in the cleaning process to treat a substrate (object to be cleaned) having tin-containing water-soluble flux residue is preferably 1 mS/m or more, more preferably 10 mS/m or more, and even more preferably 30 mS/m or more, from the viewpoint of maintaining solubility of eluted tin (e.g., divalent or tetravalent tin). Also, from the viewpoint of suppressing component damage, the electrical conductivity I is preferably 250 mS/m or less, more preferably 200 mS/m or less, and even more preferably 150 mS/m or less. In one or more embodiments, the electrical conductivity I is preferably 400 mS/m or less, more preferably 350 mS/m or less, and even more preferably 300 mS/m or less, from the viewpoint of suppressing component damage. In one or more embodiments, the electrical conductivity I may be 100 mS/m or less, or may be 50 mS/m or less.
More specifically, in one or more embodiments, the conductivity I is preferably 1 mS/m or more and 250 mS/m or less, more preferably 10 mS/m or more and 200 mS/m or less, and even more preferably 30 mS/m or more and 150 mS/m or less. In one or more embodiments, the conductivity I is preferably 1 mS/m or more and 400 mS/m or less, more preferably 10 mS/m or more and 350 mS/m or less, and even more preferably 30 mS/m or more and 300 mS/m or less.
In one or more embodiments of the present disclosure, the electrical conductivity II (hereinafter also simply referred to as "electrical conductivity II") when the composition used to treat the substrate (object to be cleaned) in the cleaning step is diluted 100 times is, from the viewpoint of maintaining the solubility of eluted tin (e.g., divalent or tetravalent tin), preferably 0.5 mS/m or more, more preferably 1.0 mS/m or more, and even more preferably 2 mS/m or more, and, from the viewpoint of suppressing damage to components, is preferably 20 mS/m or less, more preferably 15 mS/m or less, and even more preferably 10 mS/m or less.
In one or more embodiments, the electrical conductivity II is preferably 0.5 mS/m or more, more preferably 1.0 mS/m or more, and even more preferably 2 mS/m or more, from the viewpoint of maintaining the solubility of eluted tin (e.g., divalent or tetravalent tin), and from the viewpoint of suppressing damage to components, it is preferably 50 mS/m or less, more preferably 40 mS/m or less, and even more preferably 30 mS/m or less.
More specifically, in one or more embodiments, the conductivity II is preferably 0.5 mS/m or more and 20 mS/m or less, more preferably 1.0 mS/m or more and 15 mS/m or less, and even more preferably 2 mS/m or more and 10 mS/m or less. In one or more embodiments, the conductivity II is preferably 0.5 mS/m or more and 50 mS/m or less, more preferably 1.0 mS/m or more and 40 mS/m or less, and even more preferably 2 mS/m or more and 30 mS/m or less.
In the present disclosure, the ratio [II/I] of electrical conductivity II to electrical conductivity I is 0.03 or more, preferably 0.05 or more, and more preferably 0.07 or more, from the viewpoint of suppressing the generation of insoluble tin precipitates, and is 1.0 or less, preferably less than 1.0, preferably 0.5 or less, and more preferably 0.3 or less, from the viewpoint of improving the removability of tin-containing water-soluble flux. More specifically, the electrical conductivity ratio [II/I] is in the range of 0.03 or more and 1.0 or less, preferably 0.05 or more and 0.5 or less, and more preferably 0.07 or more and 0.3 or less.
In one or more embodiments, the conductivities I and II in the present disclosure can be adjusted by the concentration of component B.
In the present disclosure, the electrical conductivity can be calculated by the method described in the Examples.

(Component A: organic solvent)
The organic solvent contained or blended in the composition of the present disclosure (hereinafter also referred to as "component A") may be one type or a combination of two or more types.
In one or more embodiments, from the viewpoint of improving the removability of tin-containing water-soluble flux, Component A is preferably at least one solvent selected from the group consisting of compounds represented by the following formula (I) and compounds represented by the following formula (II):

<Compound represented by formula (I)>
R ¹ -O-(AO) _n -R ² (I)
In the above formula (I), ^R1 is a phenyl group or an alkyl group having 1 to 8 carbon atoms, ^R2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, AO is an ethylene oxide group or a propylene oxide group, and n is the number of moles of AO added and is an integer of 1 to 3.

In the above formula (I), in one or more embodiments, ^R1 represents a phenyl group or an alkyl group having 1 to 8 carbon atoms. From the viewpoint of improving the removability of the tin-containing water-soluble flux, R1 is preferably a phenyl group or an alkyl group having 4 to 6 carbon atoms, and more preferably an alkyl group having 4 to 6 carbon atoms.
In the above formula (I), in one or more embodiments, ^R2 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and from the same viewpoint, a hydrogen atom or an alkyl group having 2 to 4 carbon atoms is preferable, and a hydrogen atom is more preferable.
In one or more embodiments, AO in the above formula (I) is an ethyleneoxy group or a propyleneoxy group, and from the same viewpoint, an ethyleneoxy group is preferred.
In the above formula (I), in one or more embodiments, n is an integer of 1 or more and 3 or less, and from the same viewpoint, 1 or 2 is preferable, and 2 is more preferable.

Examples of compounds represented by formula (I) above include monophenyl ethers such as ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, and triethylene glycol monophenyl ether; monoalkyl ethers having an alkyl group with 1 to 8 carbon atoms, such as ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether, and triethylene glycol monoalkyl ether; dialkyl ethers having an alkyl group with 1 to 8 carbon atoms and an alkyl group with 1 to 4 carbon atoms, such as ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, and triethylene glycol dialkyl ether; phenyl alkyl ethers having a phenyl group and an alkyl group with 1 to 4 carbon atoms, such as ethylene glycol phenyl alkyl ether, diethylene glycol phenyl alkyl ether, and triethylene glycol phenyl alkyl ether; and the like. Among these, from the viewpoint of improving the removability of tin-containing water-soluble flux, preferred examples include ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, and triethylene glycol dimethyl ether.

<Compound represented by formula (II)>
R ³ -CH ₂ OH (II)
In the above formula (II), ^R3 is a phenyl group, a benzyl group, or a cyclohexyl group.

In the above formula (II), in one or more embodiments, ^R3 represents a phenyl group, a benzyl group, or a cyclohexyl group. From the viewpoint of improving the removability of the tin-containing water-soluble flux, a phenyl group or a cyclohexyl group is preferable, and a phenyl group is more preferable.

Examples of the compound represented by formula (II) above include at least one selected from benzyl alcohol, phenethyl alcohol, and cyclohexanemethanol. Of these, benzyl alcohol is preferred as the compound represented by formula (II) above from the viewpoint of improving the removability of tin-containing water-soluble flux.

From the viewpoint of improving the removability of tin-containing water-soluble flux, component A is preferably a compound represented by formula (II), and more preferably benzyl alcohol.

From the viewpoint of improving the removability of tin-containing water-soluble flux, the content of component A when using the composition of the present disclosure is preferably greater than 0% by mass, more preferably greater than 0.1% by mass, and even more preferably greater than 0.2% by mass. From the viewpoint of rinsability, the content is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. More specifically, the content of component A when using the composition of the present disclosure is preferably greater than 0% by mass and 10% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, and even more preferably 0.2% by mass or more and 3% by mass or less. When component A is a combination of two or more types, the content of component A refers to the total content of those components.

(Component B: Alkaline Compound)
The alkali compound contained in or blended into the composition of the present disclosure is at least one alkali compound selected from a quaternary ammonium hydroxide and an amine compound (hereinafter, also simply referred to as "Component A"). Component A may be one type or a combination of two or more types.

<Quaternary ammonium hydroxide>
In one or more embodiments, the quaternary ammonium hydroxide may be a salt composed of a quaternary ammonium cation and hydroxide. In one or more embodiments, examples of the cation include tetraalkylammonium cations (alkyl having 1 to 4 carbon atoms) such as tetramethylammonium, tetraethylammonium, tetra(n- or i-)propylammonium, tetra(n- or i-)butylammonium, and trimethylethylammonium, as well as alkylammonium cations (alkyl having 1 to 4 carbon atoms) having a hydroxyalkyl group such as trimethyl(2-hydroxyethyl)ammonium and triethyl(2-hydroxyethyl)ammonium.

In one or more embodiments, the quaternary ammonium hydroxide is preferably a quaternary ammonium hydroxide represented by the following formula (III), from the viewpoints of improving the removability of the tin-containing water-soluble flux, maintaining the dissolution of tin ions, and suppressing the generation of insoluble tin precipitates:
In the formula (III), ^R4 , ^R5 , ^R6 , and ^R7 are each independently at least one selected from the group consisting of a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group. In the formula (III), ^R4 , ^R5 , ^R6 , and ^R7 are preferably methyl groups from the viewpoint of maintaining dissolution of tin ions.

Examples of the quaternary ammonium hydroxide represented by formula (III) above include at least one selected from tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide (choline), 2-hydroxyethyltriethylammonium hydroxide, 2-hydroxyethyltripropylammonium hydroxide, 2-hydroxypropyltrimethylammonium hydroxide, 2-hydroxypropyltriethylammonium hydroxide, 2-hydroxypropyltripropylammonium hydroxide, dimethylbis(2-hydroxyethyl)ammonium hydroxide, diethylbis(2-hydroxyethyl)ammonium hydroxide, dipropylbis(2-hydroxyethyl)ammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, tris(2-hydroxyethyl)ethylammonium hydroxide, tris(2-hydroxyethyl)propylammonium hydroxide, tetrakis(2-hydroxyethyl)ammonium hydroxide, and tetrakis(2-hydroxypropyl)ammonium hydroxide. Among these, tetramethylammonium hydroxide (TMAH) is preferred from the viewpoint of maintaining the dissolution of tin ions.

<Amine Compound>
In one or more embodiments, the amine compound is preferably an amine represented by the following formula (IV), from the viewpoints of improving the removability of the tin-containing water-soluble flux, maintaining the dissolution of tin ions, and suppressing the generation of insoluble tin precipitates.
In the above formula (IV), ^R8 represents a hydrogen atom, an alkyl group, a phenyl group, a benzyl group, a hydroxyethyl group, a hydroxypropyl group, or an aminoethyl group, ^R9 represents a hydrogen atom, a hydroxyethyl group, a hydroxypropyl group, or an alkyl group, and ^R10 represents a hydroxyethyl group, a hydroxypropyl group, or an alkyl group. Examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms.

In the above formula (IV), in one or more embodiments, ^R8 represents a hydrogen atom, an alkyl group, a phenyl group, a benzyl group, a hydroxyethyl group, a hydroxypropyl group, or an aminoethyl group. From the viewpoints of improving the removability of the tin-containing water-soluble flux, maintaining the dissolution of tin ions, and suppressing the formation of insoluble tin precipitates, R8 is preferably an alkyl group, more preferably an alkyl group having from 1 to 6 carbon atoms, and even more preferably a methyl group or an ethyl group.
In one or more embodiments, R ⁹ represents a hydrogen atom, a hydroxyethyl group, a hydroxypropyl group, or an alkyl group, and from the same viewpoint, a hydrogen atom is preferred.
In one or more embodiments, R ¹⁰ represents a hydroxyethyl group, a hydroxypropyl group, or an alkyl group, and from the same viewpoint, a hydroxyethyl group or a hydroxypropyl group is preferred, and a hydroxyethyl group is more preferred.

Examples of the amine represented by formula (IV) above include at least one selected from alkanolamines such as monoethanolamine (MEA), monoisopropanolamine, N-methylmonoethanolamine, N-methylisopropanolamine, N-ethylmonoethanolamine, N-ethylisopropanolamine, diethanolamine, diisopropanolamine, N-dimethylmonoethanolamine, N-dimethylmonoisopropanolamine, N-methyldiethanolamine, N-methyldiisopropanolamine, N-diethylmonoethanolamine, N-diethylmonoisopropanolamine, N-ethyldiethanolamine, N-butyldiethanolamine, N-ethyldiisopropanolamine, N-(β-aminoethyl)ethanolamine, N-(β-aminoethyl)isopropanolamine, N-(β-aminoethyl)diethanolamine, N-(β-aminoethyl)diisopropanolamine, and N,N-dibutylethanolamine (dibutylaminoethanol); and aromatic amines such as dimethylbenzylamine.

In one or more embodiments, from the viewpoint of improving water-soluble flux removability and formulation, the polar term (δp) of the Hansen solubility parameter of Component B is 7.0 MPa ^or more, preferably greater than 7.5 ^MPa , more preferably 7.8 MPa or ^more , even more preferably greater than ^7.8 MPa, and even more preferably ^8.0 MPa or more. Also, from the viewpoint of improving water-soluble flux removability and formulation, the polar term (δp) of the Hansen solubility parameter of Component B is preferably 15 MPa ^or less, preferably 11 MPa ^or less, preferably 9 MPa ^or less, and preferably 8.8 MPa ^or less.
In this disclosure, the Hansen solubility parameter (hereinafter also referred to as "HSP") is a value used to predict the solubility of a substance, which was published by Charles M. Hansen in 1967, and is a parameter based on the idea that "two substances with similar intermolecular interactions are likely to dissolve in each other." The HSP is composed of the following three parameters (unit: MPa ^0.5 ):
δd: Energy due to intermolecular dispersion forces δp: Energy due to intermolecular dipole interactions δh: Energy due to intermolecular hydrogen bonds Detailed explanations are given in the March 2010 issue of Chemical Industry (Chemical Industry Co., Ltd.), and the Hansen solubility parameters of various substances can be obtained by using computer software such as "HSPiP: Hansen Solubility Parameters in Practice."

From the viewpoints of suppressing damage to components, maintaining dissolution of tin ions, and suppressing the formation of insoluble tin precipitates, in one or a plurality of embodiments, component B is preferably an amine compound, more preferably an amine represented by formula (IV) above, even more preferably an alkanolamine in which R ¹⁰ in formula (IV) above is a hydroxyethyl group or a hydroxypropyl group, and still more preferably N-methylmonoethanolamine.
From the viewpoint of improving water-soluble flux removability and formulation, in one or more embodiments, component B preferably comprises an amine compound having a polar term (δp) of the Hansen solubility parameter greater than 7.5 ^MPa , more preferably an amine compound having a polar term (δp) of the Hansen solubility parameter greater than 7.5 ^MPa , which contains an amine represented by formula (IV) above. From the viewpoint of improving water-soluble flux removability and formulation, in one or more embodiments, component B preferably comprises an amine compound having a polar term (δp) of the Hansen solubility parameter greater than 7.8 ^MPa , more preferably an amine compound having a polar term (δp) of the Hansen solubility parameter greater than 7.8 ^MPa , which contains an amine represented by formula (IV) above.
An example of an amine compound having a polar term (δp) of the Hansen solubility parameter of greater than 7.5 MPa ^0.5 is N-methylmonoethanolamine (8.8 MPa ^0.5 ).

In one or more embodiments, the content of component B when using the composition of the present disclosure is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of maintaining dissolution of tin ions and suppressing the formation of insoluble tin precipitates. From the viewpoint of suppressing damage to components, the content is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably less than 0.5% by mass. More specifically, in one or more embodiments, the content of component B when using the composition of the present disclosure is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, even more preferably 0.1% by mass or more and 3% by mass or less, and even more preferably 0.1% by mass or more and less than 0.5% by mass. When component B is a combination of two or more types, the content of component B refers to the total content thereof.
In one or more embodiments, the content of component B when using the composition of the present disclosure is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of maintaining dissolution of tin ions and suppressing the generation of insoluble tin precipitates, and from the viewpoint of suppressing damage to components, it is preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 6% by mass or less, and even more preferably less than 5% by mass. More specifically, in one or more embodiments, the content of component B when using the composition of the present disclosure is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 8% by mass or less, even more preferably 0.1% by mass or more and 6% by mass or less, and even more preferably 0.1% by mass or more and less than 5% by mass.
When component B is a quaternary ammonium hydroxide, the content of the quaternary ammonium hydroxide during use of the composition of the present disclosure is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of maintaining dissolution of tin ions and suppressing the formation of insoluble tin precipitates. From the viewpoint of suppressing damage to components, the content is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably less than 0.5% by mass. More specifically, the content of the quaternary ammonium hydroxide during use of the composition of the present disclosure is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, even more preferably 0.1% by mass or more and 3% by mass or less, and even more preferably 0.1% by mass or more and less than 0.5% by mass. When two or more types of quaternary ammonium hydroxides are used in combination, the content of the quaternary ammonium hydroxides refers to the total content of the quaternary ammonium hydroxides.
When component B is an amine compound, the content of the amine compound during use of the composition of the present disclosure is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of maintaining dissolution of tin ions and suppressing the generation of insoluble tin precipitates. From the viewpoint of suppressing damage to components, the content is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably less than 3% by mass. More specifically, the content of the amine compound during use of the composition of the present disclosure is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, even more preferably 0.1% by mass or more and 3% by mass or less, and even more preferably 0.1% by mass or more and less than 3% by mass. When two or more amine compounds are used in combination, the content of the amine compounds refers to the total content thereof.

In one or more embodiments, the mass ratio of the content (mass%) of component B to the content (mass%) of component A during use of the composition of the present disclosure, i.e., the mass ratio B/A of components B to A in the composition of the present disclosure, is preferably 0.5 or more, more preferably 0.7 or more, and even more preferably 0.9 or more, from the viewpoint of maintaining dissolution of tin ions and suppressing the generation of insoluble tin precipitates, and is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.0 or less, from the viewpoint of suppressing damage to components. More specifically, in one or more embodiments, the mass ratio B/A is preferably 0.5 or more and 2.0 or less, more preferably 0.7 or more and 1.5 or less, and even more preferably 0.9 or more and 1.0 or less.
In one or more embodiments, from the viewpoint of maintaining dissolution of tin ions and suppressing the generation of insoluble tin precipitates, the mass ratio B/A is preferably 0.1 or more, more preferably 0.3 or more, and even more preferably 0.5 or more, and from the viewpoint of suppressing damage to components, it is preferably 10.0 or less, more preferably 5 or less, and even more preferably 2 or less. More specifically, in one or more embodiments, the mass ratio B/A is preferably 0.1 or more and 10.0 or less, more preferably 0.3 or more and 5 or less, and even more preferably 0.5 or more and 2.0 or less.

(Component C: water)
Examples of water contained in or blended into the composition of the present disclosure (hereinafter also referred to as "component C") include ion-exchanged water, RO water (water treated by a reverse osmosis membrane), distilled water, pure water, and ultrapure water.
The content of component C when using the composition of the present disclosure is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more from the viewpoint of improving the removability of tin-containing water-soluble flux, and from the viewpoint of maintaining the dissolution of tin ions and suppressing the generation of insoluble tin precipitates, it is preferably 99.99% by mass or less, more preferably 99.95% by mass or less, and even more preferably 99.90% by mass or less. More specifically, the content of component C when using the composition of the present disclosure is preferably 80% by mass or more and 99.99% by mass or less, more preferably 90% by mass or more and 99.95% by mass or less, and even more preferably 95% by mass or more and 99.90% by mass or less.

The mass ratio B/C of component B to component C in the composition of the present disclosure [content of component B (mass%) / content of component C (mass%)] is preferably 0.0005 or more, more preferably 0.005 or more, and even more preferably 0.05 or more, from the viewpoint of maintaining the dissolution of tin ions and suppressing the formation of insoluble tin precipitates. From the viewpoint of component damage, it is preferably 0.11 or less, more preferably 0.10 or less, and even more preferably 0.09 or less. More specifically, the mass ratio B/C is preferably 0.0005 or more and 0.11 or less, more preferably 0.005 or more and 0.07 or less, and even more preferably 0.05 or more and 0.09 or less.

The mass ratio C/A of component C to component A in the composition of the present disclosure [content of component C (mass%) / content of component A (mass%)] is preferably 1 or greater, more preferably 4 or greater, and even more preferably 9 or greater, from the viewpoint of improving the water-soluble flux cleaning performance. Also, from the viewpoint of improving the water-soluble flux cleaning speed, it is preferably 10,000 or less, more preferably 500 or less, and even more preferably 250 or less. More specifically, the mass ratio C/A is preferably 1 or greater and 10,000 or less, more preferably 4 or greater and 500 or less, and even more preferably 9 or greater and 250 or less.

(Component D: Heterocyclic Aromatic Compound)
In one or more embodiments, the composition of the present disclosure may further contain or be formulated with a heterocyclic aromatic compound (including a salt thereof) (hereinafter also referred to as "Component D"). Component D may be one type or a combination of two or more types.

From the viewpoint of suppressing damage to components, component D is preferably a heterocyclic aromatic compound containing two or more nitrogen atoms in the heterocycle, more preferably three or more nitrogen atoms in the heterocycle, and preferably nine or fewer nitrogen atoms in the heterocycle, more preferably five or fewer nitrogen atoms in the heterocycle, and even more preferably four or fewer nitrogen atoms in the heterocycle.

In one or more embodiments, Component D is preferably at least one selected from 1,2,4-triazole, 3-amino-1,2,4-triazole, 5-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 1H-tetrazole, 5-aminotetrazole, 1H-benzotriazole (BTA), 1H-tolyltriazole, 2-aminobenzotriazole, 3-aminobenzotriazole, and alkyl- or amine-substituted derivatives thereof. Examples of the alkyl group in the alkyl substituent include lower alkyl groups having 1 to 4 carbon atoms, and in one or more embodiments, methyl and ethyl groups. In one or more embodiments, examples of the amine substituent include 1-[N,N-bis(hydroxyethylene)aminomethyl]benzotriazole and 1-[N,N-bis(hydroxyethylene)aminomethyl]tolyltriazole. Among these, 1H-benzotriazole (BTA) is preferred as Component D from the viewpoint of suppressing damage to components.

When the composition of the present disclosure contains or is blended with Component D, in one or more embodiments, the content of Component D when the composition of the present disclosure is used is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more, from the viewpoint of suppressing damage to components, and from the viewpoint of blendability, is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less. More specifically, in one or more embodiments, the content of Component D when the composition of the present disclosure is used is preferably 0.001% by mass or more and 1.0% by mass or less, more preferably 0.005% by mass or more and 0.5% by mass or less, and even more preferably 0.01% by mass or more and 0.1% by mass or less.
In one or more embodiments, from the viewpoint of blendability, the content of component D when the composition of the present disclosure is used is preferably 5.0% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.0% by mass or less. More specifically, in one or more embodiments, the content of component D when the composition of the present disclosure is used is preferably 0.001% by mass or more and 5.0% by mass or less, more preferably 0.005% by mass or more and 2.0% by mass or less, and even more preferably 0.01% by mass or more and 1.0% by mass or less.
When Component D is a combination of two or more types, the content of Component D refers to the total content thereof.

The mass ratio B/D of component B to component D in the composition of the present disclosure [content of component B (mass%)/content of component D (mass%)] is preferably 0.001 or more, more preferably 0.01 or more, and even more preferably 0.1 or more, in order to maintain the dissolution of tin ions and suppress the formation of insoluble tin precipitates. From the viewpoint of suppressing damage to components, it is preferably 1000 or less, more preferably 700 or less, and even more preferably 500 or less. More specifically, the mass ratio B/D is preferably 0.001 or more and 1000 or less, more preferably 0.01 or more and 700 or less, and even more preferably 0.1 or more and 500 or less.

(Component E: Chelating Agent)
In one or more embodiments, the composition of the present disclosure may further contain or be formulated with a chelating agent (hereinafter also referred to as "component E"). Component E may be one type or a combination of two or more types.
From the viewpoint of inhibiting tin deposition, Component E includes at least one organic acid selected from hydroxycarboxylic acids and phosphonic acids, with phosphonic acids being preferred. Examples of hydroxycarboxylic acids include citric acid, malic acid, tartaric acid, gluconic acid, and salts thereof. Examples of phosphonic acid compounds include etidronic acid (1-hydroxyethane-1,1-diphosphonic acid, HEDP) and salts thereof. Preferred salts include alkali metal salts such as sodium salts and potassium salts.

When the composition of the present disclosure contains or is formulated with component E, the content of component E when the composition of the present disclosure is used is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more, from the viewpoint of suppressing tin deposition, and is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, from the viewpoint of preventing component damage. More specifically, the content of component E when the composition of the present disclosure is used is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.05% by mass or more and 3% by mass or less, and even more preferably 0.1% by mass or more and 1% by mass or less. When component E is a combination of two or more types, the content of component E refers to the total content of those components.

The content or blending amount of Component B in the composition of the present disclosure is preferably greater than the content or blending amount of Component E from the viewpoint of component damage resistance.
The mass ratio B/E of component B to component E in the composition of the present disclosure [content (mass%) of component B/content (mass%) of component E] is preferably 0.01 or more, more preferably 0.1 or more, and even more preferably 0.5 or more from the viewpoint of component damage resistance, and is preferably 1,000 or less, more preferably 500 or less, and even more preferably 200 or less from the viewpoint of tin deposition suppression. More specifically, the mass ratio B/E is preferably 0.01 or more and 1,000 or less, more preferably 0.1 or more and 500 or less, and even more preferably 0.5 or more and 200 or less.

In one or more embodiments, the total content of Components A, B, and C in the composition of the present disclosure is preferably 90% by mass or more, more preferably 92% by mass or more, more preferably 95% by mass or more, more preferably 98% by mass or more, more preferably 99% by mass or more, and even more preferably 99.5% by mass or more, from the viewpoints of improving the removability of water-soluble flux residue and maintaining the solubility of tin in an eluted state. In one or more embodiments, the total content of Components A, B, and C in the composition of the present disclosure may be 100% by mass.
In one or more embodiments, the total content of Components A, B, C, D, and E in the composition of the present disclosure is preferably 90% by mass or more, more preferably 92% by mass or more, more preferably 95% by mass or more, more preferably 98% by mass or more, more preferably 99% by mass or more, and even more preferably 99.6% by mass or more, from the viewpoints of improving the removability of water-soluble flux residue and maintaining the solubility of tin in an eluted state. In one or more embodiments, the total content of Components A, B, C, D, and E in the composition of the present disclosure may be 100% by mass.

(Other ingredients)
The composition of the present disclosure may contain or be blended with other components as needed, as long as the effects of the present disclosure are not impaired. Examples of other components include at least one selected from solvents other than Component A, alkalis other than Component B, surfactants, rust inhibitors, thickeners, dispersants, polymeric compounds, solubilizers, preservatives, bactericides, antibacterial agents, antifoaming agents, and antioxidants, which are typically used in cleaning agents.

In one or more embodiments, the composition of the present disclosure may contain or not contain a glycol ether compound. For example, the content or amount of the glycol ether compound in the composition of the present disclosure is preferably less than 5% by mass, more preferably 1% by mass or less, even more preferably 0.1% by mass or less, and even more preferably 0% by mass (i.e., not contained).
In one or more embodiments, the composition of the present disclosure may contain or not contain an acid or an ammonium salt thereof. For example, the content or amount of an acid or an ammonium salt thereof in the composition of the present disclosure is preferably less than 0.3% by mass, more preferably 0.1% by mass or less, and even more preferably 0% by mass (i.e., not contained).
In one or more embodiments, the composition of the present disclosure may contain or not contain an inorganic alkali. For example, the content or amount of inorganic alkali in the composition of the present disclosure is preferably 1% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.01% by mass or less, and even more preferably 0% by mass (i.e., not contained).

[Method of producing the composition]
The composition of the present disclosure can be produced, for example, by blending component A, component B, component C, and, if necessary, optional components (component D, other components) using a known method. In one or more embodiments, the composition of the present disclosure can be produced by blending at least component A, component B, and component C. Thus, in one aspect, the present disclosure relates to a method for producing a composition, comprising a step of blending at least component A, component B, and component C. In the present disclosure, "blending" includes mixing component A, component B, component C, and, if necessary, optional components (component D, other components) simultaneously or in any order.
In the method for producing the composition of the present disclosure, the amount of each component blended can be the same as the content of each component when the composition of the present disclosure is used as described above.
In the present disclosure, "the content of each component at the time of use of the composition" refers to the content of each component at the time of cleaning, i.e., at the time when the use of the composition for treatment or cleaning is started.
In one or more embodiments, the content of each component in the composition of the present disclosure when used can be considered to be the blended amount of each component in the composition of the present disclosure. However, if there is an effect of neutralization, the blended amount and the actual content may differ.

The composition of the present disclosure may be in a form that is used directly for cleaning, or may be prepared as a concentrate to the extent that separation, precipitation, or the like occurs and impairs storage stability. The concentrated composition of the present disclosure can be diluted at the time of use so that each component has the content described above (i.e., the content at the time of cleaning). The concentrated composition of the present disclosure can also be used by adding each component separately at the time of use. In this disclosure, "at the time of use" of the concentrate refers to the state in which the concentrate is diluted. In one or more embodiments, the concentrate may be diluted 2 to 300 times, 5 to 200 times, or 10 to 100 times.

Embodiments of the compositions disclosed herein may be so-called one-component types, in which all components are supplied to the market in a pre-mixed state, or so-called two-component types, in which components are mixed at the time of use.

[pH of composition]
The pH of the composition of the present disclosure is preferably 9.0 or higher, more preferably 9.5 or higher, and even more preferably 10.0 or higher, from the viewpoint of maintaining dissolution of tin ions and suppressing precipitation of insoluble tin oxides. From the viewpoint of suppressing damage to components, the pH is preferably 12.5 or lower, more preferably 12.0 or lower, and even more preferably 11.5 or lower. More specifically, the pH of the composition of the present disclosure is preferably 9.0 or higher and 12.5 or lower, more preferably 9.5 or higher and 12.0 or lower, and even more preferably 10.0 or higher and 11.5 or lower. The pH of the composition of the present disclosure can be adjusted using component B or a known pH adjuster. In the present disclosure, the pH of the composition is the pH at 25°C when the composition is in use, and can be measured by the method described in the Examples.

[Item to be cleaned]
In one or more embodiments, the composition of the present disclosure is used for cleaning a substrate (object to be cleaned) having tin-containing water-soluble flux residue. In one or more embodiments, the composition of the present disclosure is suitably used for removing (cleaning) tin-containing water-soluble flux residue from electronic components mounted using tin-containing solder.
Examples of objects to be cleaned include objects having reflowed solder. In one or more embodiments, the solder is a tin-containing solder. Examples of objects to be cleaned include electronic components and their manufacturing intermediates, specifically soldered electronic components and their manufacturing intermediates. More specifically, examples include electronic components and their manufacturing intermediates in which components are soldered with tin-containing solder, electronic components and their manufacturing intermediates in which components are connected via tin-containing solder, electronic components and their manufacturing intermediates in which tin-containing water-soluble flux residues are present in the gaps between tin-containing soldered components, and electronic components and their manufacturing intermediates in which tin-containing water-soluble flux residues are present in the gaps between components connected via tin-containing solder. The manufacturing intermediates are intermediate products in the manufacturing process of electronic components, including semiconductor packages and semiconductor devices, and include, for example, circuit boards on which at least one component selected from semiconductor chips, chip-type capacitors, and circuit boards is mounted by soldering using water-soluble flux, and/or circuit boards on which solder bumps are formed for soldering the components. The gap in the object to be cleaned is, for example, the space formed between a circuit board and a component (such as a semiconductor chip, a chip capacitor, or another circuit board) soldered and mounted on the circuit board, and refers to a space with a height (distance between components) of, for example, 5 to 500 μm, 10 to 250 μm, or 20 to 100 μm. The width and depth of the gap depend on the size and spacing of the mounted components and electrodes (lands) on the circuit board.

[Tin deposition inhibitor]
In one or more embodiments, the composition of the present disclosure can be used to prevent (suppress) the formation of insoluble tin precipitates after cleaning a substrate (object to be cleaned) having a tin-containing water-soluble flux residue. That is, in one or more embodiments, the composition of the present disclosure is a tin deposition inhibitor for preventing (suppressing) the formation of insoluble tin precipitates after cleaning a substrate (object to be cleaned) having a tin-containing water-soluble flux residue.
Therefore, in one aspect, the present disclosure relates to a tin deposition inhibitor (hereinafter also referred to as the "tin deposition inhibitor of the present disclosure") that contains or is blended with an organic solvent (component A), at least one alkali compound selected from a quaternary ammonium hydroxide and an amine compound (component B), and water (component C). In one or more embodiments, the tin deposition inhibitor of the present disclosure can further contain or be blended with optional components (component D, component E, other components) as necessary.
In one or more embodiments, the tin deposition inhibitor of the present disclosure can be used by being added to a cleaning liquid such as water used for cleaning a substrate (object to be cleaned) having tin-containing water-soluble flux residue.
In one or more embodiments, the tin deposition inhibitor of the present disclosure can suppress the generation of insoluble tin deposits when cleaning electronic components mounted using solder containing tin.

[Tin-containing water-soluble flux residue remover]
In one or more embodiments, the composition of the present disclosure is suitable for use in removing (cleaning) tin-containing water-soluble flux residues from electronic components mounted using tin-containing solder. That is, in one or more embodiments, the composition of the present disclosure is a tin-containing water-soluble flux residue remover for removing (cleaning) tin-containing water-soluble flux residues from electronic components mounted using tin-containing solder.
Therefore, in one aspect, the present disclosure relates to a tin-containing water-soluble flux residue remover (hereinafter also referred to as the "remover of the present disclosure") that contains or is a combination of an organic solvent (component A), at least one alkali compound selected from a quaternary ammonium hydroxide and an amine compound (component B), and water (component C). In one or more embodiments, the remover of the present disclosure can further contain or be combined with optional components (component D, component E, and other components) as needed.
In one or more embodiments, the remover of the present disclosure can suppress the generation of insoluble tin precipitates when cleaning electronic components mounted using tin-containing solder. In one or more embodiments, the remover of the present disclosure can suppress the generation of insoluble tin precipitates while efficiently removing tin-containing water-soluble flux residue remaining in gaps between soldered components.

[Electronic component manufacturing method]
In one aspect, the present disclosure relates to a manufacturing method for electronic components (hereinafter also referred to as the "manufacturing method for electronic components of the present disclosure") that includes a flux cleaning step using the cleaning method of the present disclosure. In one or more embodiments, the flux cleaning step is a step of cleaning an object to be cleaned using the cleaning method of the present disclosure. Examples of the object to be cleaned include the objects described above. For example, in one or more embodiments, the manufacturing method for electronic components of the present disclosure includes at least one step selected from the steps of mounting at least one component selected from a semiconductor chip, a chip capacitor, and a circuit board on a circuit board by soldering using a water-soluble flux, and the step of forming solder bumps on the circuit board for connecting the components, etc., and a step (flux cleaning step) of cleaning at least one selected from the circuit board on which the component is mounted and the circuit board on which the solder bumps are formed using the cleaning method of the present disclosure. Soldering using a water-soluble flux is performed, for example, using a lead-free solder containing tin, and may be performed by a reflow method or a flow method. Electronic components include semiconductor packages without semiconductor chips, semiconductor packages with semiconductor chips, and semiconductor devices. The method for manufacturing electronic components disclosed herein reduces tin-containing water-soluble flux residue remaining in gaps between soldered components and around solder bumps by performing cleaning using the cleaning method disclosed herein, thereby suppressing short circuits between electrodes and poor adhesion caused by the remaining tin-containing water-soluble flux residue, thereby enabling the manufacture of highly reliable electronic components. Furthermore, cleaning using the cleaning method disclosed herein facilitates the removal (cleaning) of tin-containing water-soluble flux residue remaining in gaps between soldered components and suppresses the formation of insoluble tin precipitates, thereby shortening cleaning time and improving the manufacturing efficiency of electronic components.

[kit]
In one aspect, the present disclosure relates to a kit for producing the composition of the present disclosure (hereinafter also referred to as the "kit of the present disclosure"). In one or more embodiments, the kit of the present disclosure is a kit for use in either the cleaning method of the present disclosure or the method for producing an electronic component of the present disclosure. The kit of the present disclosure can provide a composition that can suppress the generation of insoluble tin precipitates when cleaning electronic components mounted using solder containing tin.
One embodiment of the kit of the present disclosure is a kit (two-liquid cleaning composition) that contains a solution containing component A (first liquid) and a solution containing component B (second liquid) in a mutually unmixed state, and at least one selected from the first and second liquids further contains part or all of component C (water), and the first and second liquids are mixed at the time of use. After the first and second liquids are mixed, they may be diluted with component C (water) as needed. Each of the first and second liquids may contain the above-mentioned optional components (component D, component E, and other components) as needed.

The present disclosure will be explained in detail below using examples, but the present disclosure is not limited to these examples in any way.

1. Preparation of Cleaning Compositions (Examples 1 and 2, Comparative Examples 1 to 3)
Example 1
The cleaning composition of Example 1 used was the composition of Formulation 1 shown in Table 1. The composition of Formulation 1 was prepared as follows.
Benzyl alcohol (component A), N-methylethanolamine (component B), benzotriazole (component D), and water (component C) were blended in a 100 mL glass beaker and mixed under the conditions below to obtain a composition (pH: 11.1) of formulation 1. The blend amount (active ingredient, mass %) of each component in the composition of formulation 1 is shown in Table 1.
<Mixing conditions>
Liquid temperature: 25℃
Stirrer: Magnetic stirrer (50 mm rotor)
Rotation speed: 300 rpm
Stirring time: 10 minutes (Example 2)
The cleaning composition of Example 2 used was the composition of Formulation 2 shown in Table 1. The composition of Formulation 2 was prepared as follows.
Benzyl alcohol (ingredient A), N-methylethanolamine (ingredient B), etidronic acid (ingredient E), and water (ingredient C) were blended in a 100 mL glass beaker and mixed under the same mixing conditions as for formulation 1 to obtain a composition of formulation 2 (pH: 11.0). The blend amount (active ingredient, % by mass) of each component in the composition of formulation 2 is shown in Table 1.
(Comparative Example 3)
The cleaning composition of Comparative Example 3 used was the composition of Formulation 3 shown in Table 1. The composition of Formulation 3 was prepared as follows.
Benzyl alcohol (component A), butyldiethanolamine (component B), etidronic acid (component E), and water (component C) were combined in a 100 mL glass beaker and mixed under the same mixing conditions as in Example 1 to obtain a composition of formulation 3 (pH: 11.0). The amount of each component (active ingredient, % by mass) in the composition of formulation 3 is shown in Table 1.
The amount of water in Table 1 includes the amount of water contained in the acid aqueous solution and the like.

(Comparative Example 1)
For the cleaning composition of Comparative Example 1, water (pH: 7.1) was used.
(Comparative Example 2)
For the cleaning composition of Comparative Example 2, an aqueous KOH solution (concentration used: 0.1% by mass, pH: 13.1) was used.

The following materials were used to prepare each of the cleaning compositions.
Benzyl alcohol [Tokyo Chemical Industry Co., Ltd.]
N-methylethanolamine [Tokyo Chemical Industry Co., Ltd.]
Butyldiethanolamine [Amino Alcohol MBD, manufactured by Nippon Nyukazai Co., Ltd.]
Water [pure water of 1 μS/cm or less produced using the Organo Corporation G-10DSTSET water purification system]
Benzotriazole [Tokyo Chemical Industry Co., Ltd.]
Etidronic acid (HEDP) [Italmatch Japan Co., Ltd., Dequest 2010, solid content 60% by mass]
KOH [Tokyo Chemical Industry Co., Ltd.]

[Physical properties of component B]
The polarity term (δp) of the Hansen solubility parameters of component B used in preparing the cleaning composition is shown in Table 2. The polarity term (δp) was calculated using the computer software "HSPiP: Hansen Solubility Parameters in Practice."

2. Parameter measurement method [Evaluation of conductivity]
The conductivity was evaluated according to the following procedure.
20 g of each cleaning composition was added to a 50 mL glass beaker, and the conductivity (unit: mS/m) at 25°C was measured using a benchtop electrical conductivity meter "DS-72" (manufactured by HORIBA Co., Ltd.) The value was read 3 minutes after immersing the electrode in the cleaning composition.

[Evaluation of pH]
The pH was evaluated according to the following procedure.
20 g of each cleaning composition was added to a 50 mL glass beaker, and the pH was measured at 25° C. using a pH meter (manufactured by Toa TDK Corporation). The value was read 3 minutes after immersing the electrode in the cleaning composition.

3. Evaluation of Cleaning Compositions The cleaning compositions of Examples 1 and 2 and Comparative Examples 1 to 3 were evaluated as follows.

[Evaluation of the amount of dissolved tin compounds]
The amount of dissolved tin compound was evaluated according to the following procedure.
A rotor and 20 g of each detergent composition were placed in a 50 mL glass beaker, and the beaker was immersed in a water bath heated to 70°C.
Next, 0.5 g of each tin reagent (tin (0-valent) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), tin oxide (2-valent) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), tin oxide (4-valent) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)) was added to a beaker and stirred at 600 rpm at 70°C for 1 hour.
The cleaning composition was collected from the beaker, filtered (25HP020AN, manufactured by ADVANTEC Corporation), and then diluted 10-fold with ultrapure water. The resulting sample was used to calculate the amounts of tin (zerovalent, divalent, and tetravalent) dissolved in the cleaning composition by ICP emission spectroscopy (Agilent 5100/5110 ICP-OES, manufactured by Agilent Technologies). Furthermore, the amount of tin oxide (divalent) dissolved when the cleaning composition was diluted 100-fold was also calculated.
The amount dissolved was calculated using a calibration curve method using a tin standard solution (Sn1000) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) The results are shown in Table 3. The values in Table 3 are converted values before dilution, and it can be evaluated that the higher the value, the higher the amount of tin compound dissolved.
In Table 3, A, B, C, and D represent the following dissolution amounts.
A: amount of dissolved tin (zero valent) (amount of dissolved Sn(0))
B: Amount of dissolved tin (divalent) (amount of dissolved SnO (II))
C: Amount of dissolved tin (tetravalent) (amount of dissolved SnO ₂ (IV))
D: Amount of tin (divalent) dissolved (the amount of tin (divalent) oxide dissolved was evaluated when the cleaning composition used in B was diluted 100 times with water)

[Evaluation of cleaning ability of insoluble tin compounds and prevention of generation of insoluble tin compounds]
Tin is used as the main component of solder alloys, and from the viewpoint of reducing damage to components and preventing the generation of insoluble tin compounds, it is preferable that the value of A (amount of dissolved Sn(O)) is small. On the other hand, it is known that tin oxide present on the solder surface dissolves into the flux during the process of heating the substrate (Reference: JP 2000-042786, 0009 A). From the viewpoint of cleaning and removing the dissolved tin component, the values of B (amount of dissolved SnO(II)), C (amount of dissolved _SnO2 (IV)), and D (amount of dissolved SnO(II) when diluted 100 times) must be greater than zero.
From the viewpoint of preventing the generation of insoluble tin compounds, it is preferable that the values of B and C are large. In the rinsing process after flux removal, a small amount of cleaning liquid is carried into the rinsing tank. From the viewpoint of preventing the generation of insoluble tin compounds, it is preferable that the value of D is large.
Based on the above, the cleaning ability of insoluble tin compounds and the prevention of the generation of insoluble tin compounds were evaluated based on the following evaluation criteria. The results are shown in Table 3.
<Evaluation criteria for cleaning properties of insoluble tin compounds>
2: The dissolved amounts B, C, and D exceed 10. 1: The dissolved amounts B, C, and D exceed 0 and are 10 or less. 0: Any of the dissolved amounts B, C, and D is 0. <Evaluation criteria for prevention of generation of insoluble tin compounds>
1: Of the dissolution amounts A to D, dissolution amount A is the smallest value. 0: Of the dissolution amounts A to D, dissolution amount A is equal to the other dissolution amounts or the dissolution amounts other than dissolution amount A are lower than dissolution amount A.

[Evaluation of component damage]
The tin reagent (tin (zero valence) (Fujifilm Wako Pure Chemical Industries, Ltd.)) used to evaluate the amount of dissolved tin compounds was observed using a scanning electron microscope (JCM-7000 NeoScope, manufactured by JEOL Ltd.), and damage to the components was evaluated according to the following evaluation criteria. The results are shown in Table 3.
<Evaluation criteria>
A: There is no change in appearance before and after cleaning.
B: Partial change after cleaning C: 30 to 70% of the total surface changed after cleaning D: More than 70% of the total surface changed after cleaning When observing the surface of the tin reagent used in the above evaluation, the presence of irregularities was confirmed. When component damage was evaluated using the cleaning compositions of Examples 1 and 2 and Comparative Examples 1 and 3, it was confirmed that there was no change in appearance before and after cleaning. Furthermore, when component damage was evaluated using the cleaning composition of Comparative Example 2, it was confirmed that the surface irregularities were removed after cleaning, and that there was damage to the tin surface.

As shown in Table 3 above, the cleaning compositions of Examples 1 and 2 were able to suppress the solubility of undissolved tin (zerovalent tin) compared to Comparative Examples 1 and 2, and were able to maintain the solubility of dissolved tin (e.g., divalent or tetravalent tin) during cleaning and rinsing. These compositions were evaluated as having excellent cleaning performance for insoluble tin compounds and suppressing the generation of insoluble tin compounds. Furthermore, Examples 1 and 2, which had a conductivity ratio II/I of 0.07, further suppressed the generation of insoluble tin compounds compared to Comparative Example 3, which had a conductivity ratio II/I of 0.02. Therefore, it is believed that the compositions of the present disclosure can suppress the generation of insoluble tin precipitates when cleaning substrates containing tin-containing water-soluble flux residues.

The cleaning method disclosed herein can, for example, shorten the cleaning time for water-soluble flux in the semiconductor device manufacturing process and improve the performance and reliability of the manufactured semiconductor device, thereby improving the productivity of semiconductor devices.

Claims (15)

The method includes a cleaning step of treating a substrate having a tin-containing water-soluble flux residue with a composition containing an organic solvent (component A), at least one alkaline compound selected from a quaternary ammonium hydroxide and an amine compound (component B), and water (component C),
The content of component C in the composition is 80% by mass or more,
A method for cleaning a tin-containing water-soluble flux, wherein the ratio [II/I] of the following electrical conductivity II to the following electrical conductivity I is in the range of 0.03 to 1.0.
Conductivity I: Conductivity of the composition used to treat the substrate in the cleaning step Conductivity II: Conductivity when the composition used to treat the substrate in the cleaning step is diluted 100 times The cleaning method according to claim 1, wherein the mass ratio B/A of the content of component B to the content of component A in the composition is 0.1 or more and 10.0 or less. The cleaning method described in claim 1, wherein the conductivity II is 0.5 mS/m or more and 50 mS/m or less. 2. The cleaning method according to claim 1, wherein component A is at least one solvent selected from the group consisting of compounds represented by the following formula (I) and compounds represented by the following formula (II):
R ¹ -O-(AO) _n -R ² (I)
In the above formula (I), ^R1 is a phenyl group or an alkyl group having 1 to 8 carbon atoms, ^R2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, AO is an ethylene oxide group or a propylene oxide group, and n is the number of moles of AO added and is an integer of 1 to 3.
R ³ -CH ₂ OH (II)
In the above formula (II), ^R3 is a phenyl group, a benzyl group, or a cyclohexyl group. The cleaning method according to claim 1, wherein the mass ratio B/C of component B to component C in the composition is 0.0005 or more and 0.11 or less. The cleaning method according to claim 1, wherein the mass ratio C/A of component C to component A in the composition is 1 or more and 10,000 or less. 2. The cleaning method according to claim 1, wherein component B comprises an amine compound having a polar term (δp) of the Hansen solubility parameter of greater than 7.5 MPa ^0.5 . The cleaning method of claim 1, wherein the composition further contains a heterocyclic aromatic compound (component D). The cleaning method of claim 1, wherein the composition further contains a chelating agent (component E). 10. The cleaning method according to claim 9 , wherein component E is at least one organic acid selected from hydroxycarboxylic acids and phosphonic acids. The cleaning method according to claim 9 , wherein the content of component B in the composition is greater than the content of component E. The cleaning method according to claim 9 , wherein the mass ratio B/E of component B to component E in the composition is 0.01 or more and 1,000 or less. The cleaning method according to claim 1, wherein the cleaning step includes cleaning the substrate having the tin-containing water-soluble flux residue using a cleaning machine. The cleaning method according to claim 1, wherein the cleaning step includes contacting the substrate having the tin-containing water-soluble flux residue with the composition at a temperature of 10°C or higher and 80°C or lower. A method for manufacturing electronic components, comprising a flux cleaning step using the cleaning method according to any one of claims 1 to 14 .