TW201843354A - Plating liquid - Google Patents

Abstract

This plating liquid contains (A) a soluble salt that contains at least a first tin salt, (B) an acid selected from among organic acids and inorganic acids or a salt thereof, and (C) two surfactants, namely an amine-based surfactant (C1) and a nonionic surfactant (C2 and/or C3). The amine-based surfactant (C1) is a polyoxyethylene alkyl amine represented by general formula (1); and the nonionic surfactant (C2 and/or C3) is a condensation product of a polyoxyethylene and a polyoxypropylene represented by general formula (2) or general formula (3). In formula (1), x is 12-18 and y is 4-12. In formula (2), m is 15-30 and (n1 + n2) is 40-50. In formula (3), (m1 + m2) is 15-30 and n is 40-50.

Description

Plating solution

The present invention relates to a plating solution for forming a tin or tin alloy plating film. More specifically, it relates to a tin or tin alloy plating solution, which is suitable for forming solder bumps for semiconductor wafers or printed substrates, and has a bump height within a wide range of current density. It is uniform and suppresses generation of voids during bump formation. Still, this international application is based on Japanese Patent Application No. 61175 (special application 2017-61175) filed on March 27, 2017 and Japanese Patent Application No. 31865 (filed on February 26, 2018) (Japanese Patent Application No. 2018-31865), and uses the entire contents of Japanese Patent Application No. 2017-61175 and Japanese Patent Application No. 2018-31865.

Conventionally, a lead-tin alloy solder plating solution has been disclosed which is formed by formaldehyde condensation containing at least one selected from an acid and a salt thereof, a soluble lead compound, a soluble tin compound, a nonionic surfactant, and a naphthalenesulfonic acid. A formalin condensate of naphthalene sulfonic acid or an aqueous solution of a salt thereof (for example, refer to Patent Document 1). This plating solution contains, as an additive, a formaldehyde condensate of naphthalenesulfonic acid or a salt thereof in an amount of 0.02 to 1.50% by mass based on lead ions. Patent Document 1 describes the following gist: Even if the plating solution is plated at a high current density, lead with small surface height deviation, smoothness, and small variation in lead / tin composition ratio can be formed- Tin alloy protruding electrode.

In addition, a tin or tin alloy plating bath is disclosed which contains (A) a solubility of a tin salt and a mixture of any one of a tin salt and a predetermined metal salt such as silver, copper, bismuth, and lead. A salt, (B) an acid or a salt thereof, and (C) a specific phenanthrolinedione compound (for example, refer to Patent Document 2). Patent Literature 2 describes the gist of the fact that the plating bath contains a specific phenanthroline dione compound as an additive, so that the plating bath can be provided with an excellent uniformity of electricity over a wide range of current density. Deposition and good film appearance, can obtain a uniform composition in a wide range of current density.

Furthermore, a tin plating solution is disclosed which contains a tin ion source, at least one non-ionic surfactant, and imidazoline dicarboxylate as an additive, and 1,10-phenanthroline (for example, refer to a patent Reference 3). Patent Document 3 describes the following gist: This tin plating solution does not burn even in the plating of highly complicated printed substrates, has excellent uniformity of the in-plane film thickness distribution, and provides through-hole plating. The uniformity is also excellent. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2005-290505 (request item 1, paragraph [0004]) [Patent Document 2] Japanese Patent Laid-Open No. 2013-044001 (offer, paragraph [0010]) [Patent Document 3 ] Japanese Patent Application Publication No. 2012-087393 (offer, paragraph [0006])

[Problems to be Solved by the Invention]

For a tin or tin alloy plating solution used to form a solder bump as a plating film for a semiconductor wafer or a printed substrate, the thickness uniformity of the plating film is required, that is, the height of the solder bump Within-die (WID) uniformity. Although a tin or tin alloy plating solution containing the additives described in the above-mentioned Patent Documents 1 to 3 can improve the uniformity of the solder bumps, the quality requirements of the plating film have increased in recent years. It is required to further improve the height uniformity of the solder bump.

Also, in flip chip mounting, bumps provided on a substrate for connecting a semiconductor device are formed by plating. In this case, after the reflow process, A void called a void may be formed inside the bump, and the void may cause poor bonding. Therefore, it is required that the void is not formed. However, there is an inverse relationship between increasing the uniformity of the solder bumps and suppressing the generation of voids when the bumps are formed, and there is a demand for an additive for a plating solution that can solve these two problems.

An object of the present invention is to provide a plating solution that can achieve a high degree of uniformity of solder bumps in a wide range of current density ranges, and can suppress the generation of voids during bump formation. [Means for solving problems]

A first aspect of the present invention is a plating solution containing (A) a soluble salt containing at least a stannous salt, (B) an acid or a salt thereof selected from an organic acid and an inorganic acid, and (C) an additive. It is characterized in that the aforementioned additive includes two types of surfactants including an amine-based surfactant (C1) and a nonionic surfactant (C2 and / or C3), and the aforementioned amine-based surfactant (C1) is Polyoxyethylene alkylamine represented by the following general formula (1), and the nonionic surfactant (C2 or C3) is represented by the following general formula (2) or general formula (3) Condensate of polyoxyethylene and polyoxypropylene.

In the formula (1), x is 12 to 18, and y is 4 to 12.

In the formula (2), m is 15 to 30, and n1 + n2 is 40 to 50.

In the formula (3), m1 + m2 is 15-30, and n is 40-50.

A second aspect of the present invention is an invention based on the first aspect, and the additive further includes a surfactant, a complexing agent, a glossing agent, and an anti-surfactant different from the two types of surfactants (C1, C2, and / or C3). A plating solution made of two or more other additives among oxidants. [Effect of the invention]

In the plating solution according to the first aspect of the present invention, during plating, both the amine-based surfactant (C1) and the non-ionic surfactant (C2 and / or C3) suppress the precipitation of Sn ions, and may The surface of the object to be plated is well plated. If only the amine-based surfactant (C1) is used, the effect of suppressing the precipitation of Sn ions at a low current density will be too small, and the height of the bumps will vary when the solder bumps are formed. In addition, when only the nonionic surfactant (C2 and / or C3) is used, when the current density is increased to increase the plating speed, Sn ions near the surface of the plating target are depleted, and plating failure occurs. By including both amine-based surfactant (C1) and non-ionic surfactant (C2 and / or C3) as additives, the disadvantages of both surfactants can be complemented, even if the plating speed is increased and the The uniformity of the height (WID) of the bumps can also be achieved within the range of the current density, and the generation of voids when the bumps are formed is suppressed.

The plating solution according to the second aspect of the present invention further includes two kinds of surfactants, complexing agents, gloss agents, and antioxidants, which are different from the two types of surfactants (C1, C2, and / or C3). The other additives described above have the following effects. The surfactants different from the two types of surfactants (C1, C2, and / or C3) can obtain effects such as stabilization of the plating solution and improvement of solubility. When the plating solution contains a noble metal such as silver, the complexing agent stabilizes the noble metal ions and the like in the bath and makes the deposited alloy composition uniform. The glossing agent can impart gloss to the plating film. Furthermore, antioxidants prevent the oxidation of soluble stannous salts into n-tin salts.

[Best Mode for Implementing Invention]

Next, the best mode for carrying out the present invention will be described.

The plating solution of the present invention is a tin or tin alloy plating solution, and contains (A) a soluble salt containing at least a stannous salt, (B) an acid or a salt thereof selected from organic acids and inorganic acids, and (C) an additive . The additive includes two types of surfactants, namely, an amine-based surfactant (C1) and a non-ionic surfactant (C2 and / or C3). The amine-based surfactant (C1) is represented by the general formula (1). Polyoxyethylene alkylamine, and the nonionic surfactant (C2 or C3) is a condensation product of polyoxyethylene and polyoxypropylene represented by the general formula (2) or general formula (3). The soluble salt is composed of any one of a mixture of stannous salt and a salt of the stannous salt and a metal selected from the group consisting of silver, copper, bismuth, nickel, antimony, indium, and zinc.

The tin alloy of the present invention is an alloy of tin and a specified metal selected from silver, copper, bismuth, nickel, antimony, indium, and zinc. Examples of the alloy include tin-silver alloy, tin-copper alloy, tin-bismuth alloy, Tin-nickel alloy, tin-antimony alloy, tin-indium alloy, tin-zinc alloy binary alloy, tin-copper-bismuth, tin-copper-silver alloy and other ternary alloys.

Therefore, the soluble salt (A) of the present invention means that Sn ²⁺ , Ag ⁺ , Cu ⁺ , Cu ²⁺ , Bi ³⁺ , Ni ²⁺ , Sb ³⁺ , In ³⁺ , Zn are generated in the plating solution. Examples of any soluble salt of various metal ions such as ²⁺ include the metal salt of an oxide, halide, inorganic acid, or organic acid of the metal.

Examples of the metal oxide include stannous oxide, copper oxide, nickel oxide, bismuth oxide, antimony oxide, indium oxide, and zinc oxide. Examples of the metal halide include stannous chloride, bismuth chloride, and bismuth odor. , Cuprous chloride, copper chloride, nickel chloride, antimony chloride, indium chloride, zinc chloride, etc.

Examples of the metal salt of an inorganic or organic acid include copper sulfate, stannous sulfate, bismuth sulfate, nickel sulfate, antimony sulfate, bismuth nitrate, silver nitrate, copper nitrate, antimony nitrate, indium nitrate, nickel nitrate, zinc nitrate, and copper acetate. , Nickel acetate, nickel carbonate, sodium stannate, stannous fluoroborate, stannous methanesulfonate, silver methanesulfonate, copper methanesulfonate, bismuth methanesulfonate, nickel methanesulfonate, indium methanesulfonate, dimethylsulfonate Zinc acid, stannous ethanesulfonate, bismuth 2-hydroxypropanesulfonate and the like.

The acid or a salt thereof (B) of the present invention is selected from organic acids and inorganic acids, or a salt thereof. Examples of the organic acids include organic sulfonic acids such as alkane sulfonic acids, alkanol sulfonic acids, and aromatic sulfonic acids, or aliphatic carboxylic acids. Among the inorganic acids, fluoroboronic acid, hydrosilicofluoric acid, and aminosulfonic acids are exemplified. Acid, hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, etc. The salts are salts of alkali metals, salts of alkaline earth metals, ammonium salts, amine salts, sulfonates, and the like. From the viewpoint of solubility of a metal salt or ease of drainage treatment, the component (B) is preferably an organic sulfonic acid.

As the alkane sulfonic acid, those represented by the chemical formula C _n H _{2n + 1} SO ₃ H (for example, n = 1 to 5, preferably 1 to 3) can be used, and specifically, except for methanesulfonic acid and ethanesulfonic acid In addition to 1-propanesulfonic acid, 2-propanesulfonic acid, 1-butanesulfonic acid, 2-butanesulfonic acid, pentanesulfonic acid, etc., examples include hexanesulfonic acid, decanesulfonic acid, and dodecanesulfonic acid. Acid etc.

As the alkanol sulfonic acid, the chemical formula C _p H _{2p + 1} -CH (OH) -C _q H _2q -SO ₃ H (for example, p = 0 ~ 6, q = 1 ~ 5) can be used. Specifically, Except for 2-hydroxyethane-1-sulfonic acid, 2-hydroxypropane-1-sulfonic acid, 2-hydroxybutane-1-sulfonic acid, 2-hydroxypentane-1-sulfonic acid, etc., examples are 1-hydroxypropane-2-sulfonic acid, 3-hydroxypropane-1-sulfonic acid, 4-hydroxybutane-1-sulfonic acid, 2-hydroxyhexane-1-sulfonic acid, 2-hydroxydecane-1- Sulfonic acid, 2-hydroxydodecane-1-sulfonic acid, and the like.

The aromatic sulfonic acid is basically benzenesulfonic acid, alkylbenzenesulfonic acid, phenolsulfonic acid, naphthalenesulfonic acid, alkylnaphthalenesulfonic acid, and the like, and specific examples include 1-naphthalenesulfonic acid and 2-naphthalenesulfonic acid. , Toluenesulfonic acid, xylenesulfonic acid, p-phenolsulfonic acid, cresolsulfonic acid, sulfosalicylic acid, nitrobenzenesulfonic acid, sulfobenzoic acid, diphenylamine-4-sulfonic acid, and the like.

Examples of the aliphatic carboxylic acid include acetic acid, propionic acid, butyric acid, citric acid, tartaric acid, gluconic acid, sulfosuccinic acid, and trifluoroacetic acid.

The amine-based surfactant (C1) contained in the additive (C) of the present invention is a polyoxyethylene alkylamine represented by the following general formula (1).

In the formula (1), x is 12 to 18, and y is 4 to 12.

The nonionic surfactant (C2 or C3) contained in the additive (C) of the present invention is a condensate of polyoxyethylene and polyoxypropylene represented by the following general formula (2) or general formula (3).

In the formula (2), m is 15 to 30, and n1 + n2 is 40 to 50.

In the formula (3), m1 + m2 is 15-30, and n is 40-50.

The plating solution of the present invention preferably further contains two or more kinds of other surfactants, complexing agents, gloss agents, and antioxidants as other additives.

Examples of other surfactants at this time include ordinary anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants.

Examples of the anionic surfactant include polyoxyethylene (ethylene oxide: containing 12 moles) nonyl ether sodium sulfate, polyoxyalkylene alkyl ether sulfate, and polyoxyethylene (ethylene oxide: containing 12 moles). Mol) Polyoxyalkylene alkylphenyl ether sulfates such as sodium dodecylphenyl ether sulfate, alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate, 1-naphthol-4-sulfonate (Poly) alkylnaphthalenesulfonic acids such as sodium naphthalenesulfonic acid, disodium 2-naphthol-3,6-disulfonic acid, etc., sodium diisopropylnaphthalenesulfonate, sodium dibutylnaphthalenesulfonate, etc. Acid salts, alkyl sulfates such as sodium dodecyl sulfate, sodium olekenyl sulfate, and the like.

Examples of the cationic surfactant include mono-trialkylamine salts, dimethyldialkylammonium salts, trimethylalkylammonium salts, dodecyltrimethylammonium salts, and cetyltrimethylamine. Ammonium salt, octadecyltrimethylammonium salt, dodecyldimethylammonium salt, octadecyldimethylethylammonium salt, dodecyldimethylbenzylammonium salt, cetyl Alkyl dimethyl benzyl ammonium salt, octadecyl dimethyl benzyl ammonium salt, trimethyl benzyl ammonium salt, triethyl benzyl ammonium salt, cetyl pyridinium salt, dodecyl Pyridinium salt, dodecylmethylpyridinium salt, dodecylimidazolinium salt, oleylimidazolinium salt, stearylamine acetate, dodecylamine acetate, and the like.

Examples of nonionic surfactants include sugar esters, fatty acid esters, C ₁ to C ₂₅ alkoxy phosphates (salts), sorbitan esters, silicon polyoxyethylene ethers, silicon polyoxyethylene esters, Sulfated or sulfonated adducts of the condensation products of fluorine-based polyoxyethylene ethers, fluorine-based polyoxyethylene esters, ethylene oxide and / or propylene oxide, and alkylamines or diamines.

Examples of the amphoteric surfactant include betaine, carboxybetaine, imidazolinium betaine, sulfobetaine, and aminocarboxylic acid.

The complexing agent is used in a plating solution containing a noble metal such as silver to stabilize the noble metal ions and the like in a bath, and to uniformize the deposited alloy composition. Examples of the complexing agent include hydroxycarboxylic acid, polycarboxylic acid, and monocarboxylic acid. Specific examples include gluconic acid, citric acid, glucoheptanoic acid, gluconolactone, glucoheptolactone, formic acid, acetic acid, propionic acid, butyric acid, ascorbic acid, oxalic acid, malonic acid, succinic acid, Glycolic acid, malic acid, tartaric acid, diglycolic acid, thioglycolic acid, thiodiglycolic acid, thioethanol, thiodiethanol, thiosuccinic acid, 3,6-dithia-1,8-octane Alcohol, 3,6,9-trithiadecane-1,11-disulfonic acid, thiobis (dodecyl glycol), bis (6-methylbenzothiazolyl) dithiotrisulfonic acid, di (6-chlorobenzothiazolyl) dithiodisulfonic acid, gluconic acid, citric acid, glucoheptanoic acid, gluconolactone, glucoheptanolactone, dithiodiphenylamine, dipyridyl disulfide, mercapto amber Acid, sulfite, thiosulfate, ethylenediamine, ethylenediaminetetraacetic acid (EDTA), diethyltriaminepentaacetic acid (DTPA), nitrogen triacetate (NTA), iminodiacetic acid (IDA ), Iminodipropionic acid (IDP), hydroxyethylethylenediaminetriacetic acid (HEDTA), triethylenetetraaminehexaacetic acid (TTHA), ethylenedioxybis (ethylamine) -N, N, N ' , N'-tetraacetic acid, glycine , Nitrogen trimethylphosphonic acid, or salts thereof. In addition, there are sulfur-containing compounds such as thioureas and phosphorus compounds such as ginseng (3-hydroxypropyl) phosphine. Examples of the conductive salt include sulfuric acid, hydrochloric acid, phosphoric acid, aminosulfonic acid, sodium salt, potassium salt, magnesium salt, ammonium salt, and amine salt of sulfonic acid.

The said gloss agent is used for giving gloss to a plating film. Examples of the gloss agent include benzaldehyde, o-chlorobenzaldehyde, 2,4,6-trichlorobenzaldehyde, m-chlorobenzaldehyde, p-nitrobenzaldehyde, p-hydroxybenzaldehyde, furfural, and 1-naphthalene Formaldehyde, 2-naphthaldehyde, 2-hydroxy-1-naphthaldehyde, 3-naphthalene, benzylideneacetone, pyridylacetone, furfurylacetone, cinnamaldehyde, anisaldehyde, salicylaldehyde, crotonaldehyde, Various aldehydes such as acrolein, glutaraldehyde, paraldehyde, vanillin; triazine, imidazole, indole, quinoline, 2-vinylpyridine, aniline, phenanthroline, 2,9-dimethyl- 1,10-phenanthroline (2,9-dimethyl-1,10-phenanthroline), 2-picolinic acid, thioureas, N- (3-hydroxybutylene) -p-aminobenzenesulfonic acid, N- Butylaminobenzenesulfonic acid, N-cinnamic acid aminobenzenesulfonic acid, 2,4-diamino-6- (2'-methylimidazolyl (1 ')) ethyl-1,3,5 -Triazine, 2,4-diamino-6- (2'-ethyl-4-methylimidazolyl (1 ')) ethyl-1,3,5-triazine, 2,4-diamine -6- (2'-undecylimidazolyl (1 ')) ethyl-1,3,5-triazine, phenyl salicylate; or benzothiazole, 2-mercaptobenzothiazole, 2 -Methylbenzothiazole, 2-aminobenzothiazole, 2-amino-6-methoxybenzo Thiazole, 2-methyl-5-chlorobenzothiazole, 2-hydroxybenzothiazole, 2-amino-6-methylbenzothiazole, 2-chlorobenzothiazole, 2,5-dimethylbenzo Benzothiazoles such as thiazole, 5-hydroxy-2-methylbenzothiazole, and the like.

The antioxidant is used to prevent the soluble stannous salt from being oxidized to the normal tin salt. Examples of the antioxidant include hypophosphorous acid, ascorbic acid or a salt thereof, phenolsulfonic acid (Na), cresolsulfonic acid (Na), hydroquinone sulfonic acid (Na), hydroquinone, α, or β-naphthol, catechol, resorcinol, resorcinol, hydrazine, phenolsulfonic acid, catecholsulfonic acid, hydroxybenzenesulfonic acid, naphtholsulfonic acid, or salts thereof.

The content of the amine-based surfactant (C1) in the plating solution of the present invention is 1 to 10 g / L, and preferably 3 to 5 g / L. When the content is less than the appropriate range, the effect of suppressing Sn ions is weak. Moreover, when it is too much, the effect of suppressing the precipitation of Sn ions at a low current density is reduced, and the bump height may become uneven.

The content of the nonionic surfactant (C2 and / or C3) in the plating solution of the present invention is 1 to 10 g / L, preferably 1 to 5 g / L. When the content is less than the appropriate range, the effect of suppressing Sn ions is weak. Moreover, when it is too much, the depletion of Sn ions in the vicinity of the surface of the plating object is further promoted, and there is a possibility that plating defects such as dendrites may occur. If both the nonionic surfactant (C2) and the nonionic surfactant (C3) are contained, the total content of the nonionic surfactant (C2) and the nonionic surfactant (C3) should be included. It should just be in the said range. In the plating solution, the total content of the surfactants of both the amine-based surfactant (C1) and the non-ionic surfactant (C2 and / or C3) is 1 to 10 g / L, preferably 1 ~ 5g / L.

The soluble metal salt (A) specified above can be used alone or in combination. The content in the plating solution is 30 to 100 g / L, and preferably 40 to 60 g / L. If the content is less than a suitable range, productivity will decrease, and if the content is too large, the cost of the plating solution will increase.

The inorganic acid, organic acid or its salt (B) can be used alone or in combination. The content in the plating solution is 80 to 300 g / L, preferably 100 to 200 g / L. If the content is less than the appropriate range, the conductivity will decrease and the voltage will increase. If the content is too large, the viscosity of the plating solution will increase and the stirring speed of the plating solution will decrease.

The concentration of each component (A) to (C) above can be arbitrarily adjusted and selected according to plating methods such as barrel plating, rack plating, high-speed continuous plating, frameless plating, and bump plating.

On the other hand, the liquid temperature of the plating solution of the present invention is generally 70 ° C or lower, and preferably 10 to 40 ° C. When the plating film is formed by electroplating, the current density is in the range of 0.1 A / dm ² or more and 100 A / dm ² or less, and preferably in the range of 0.5 A / dm ² or more and 20 A / dm ² or less. When the current density is too low, productivity is deteriorated, and when it is too high, the uniformity of the height of the bumps is deteriorated.

The tin or tin alloy plating solution containing both the amine-based surfactant (C1) and the non-ionic surfactant (C2 and / or C3) as additives is suitable for electrons of a plated object. The device can form a specified metal film on an electronic device. Examples of the electronic component include a printed circuit board, a flexible printed circuit board, a film carrier, a semiconductor integrated circuit, a resistor, a capacitor, a filter, an inductor, a thermistor, a crystal oscillator, a switch, and a lead wire. In addition, the plating solution of the present invention may be used to form a film on a part of an electronic component, such as a bump on a wafer. [Example]

Next, examples of the present invention and comparative examples will be described in detail together.

(Amine-based surfactants (C1) and non-ionic surfactants (C2 or C3) used in Examples and Comparative Examples) Examples 1-1 to 1-15 and Examples 2-1 to 2- 12. Comparative Examples 1-1 to 1-11, Polyoxyethylene alkylamines (C1-1 to C1-11) of the amine surfactant (C1) used in Comparative Examples 2-1 to 2-13 The structural formula is shown in Table 1.

Non-ionic surfactants used in Examples 1-1 to 1-15, Examples 2-1 to 2-12, Comparative Examples 1-1 to 1-11, and Comparative Examples 2-1 to 2-13 ( The condensate of polyoxyethylene and polyoxypropylene of C2 or C3) is represented by the general formula (2) or the general formula (3) as described above. Table 2 shows m, n1 + n2, and molecular weights in the structural formulae (C2-1 to C2-10) of the condensate represented by the general formula (2). In addition, m1 + m2, n, and molecular weight in the structural formulas (C3-1 to C3-10) of the above-mentioned condensate represented by the general formula (3) are shown in Table 3. In the formulae (2) and (3), m represents the number of ethylene oxide (EO) groups, and n represents the number of propylene oxide (PO) groups.

(Building bath of Sn plating solution) <Example 1-1> Methanesulfonic acid as a free acid and catechol as an antioxidant were mixed in a methanesulfonic acid Sn aqueous solution to make a homogeneous solution, and further The polyoxyethylene alkylamine (mass average molecular weight: 800) of the above No. C1-3 and the polyoxyethylene and polyoxypropylene condensation product (mass average molecular weight: 3100) of the above No. C2-4 were added as a surfactant. , Polyalkylene oxide (EO) group: PO group (Mole ratio) = 15:40). Finally, ion-exchanged water was added to prepare a Sn plating solution having the following composition. The methanesulfonic acid Sn aqueous solution is prepared by electrolyzing a metal Sn plate in an methanesulfonic acid aqueous solution.

(Composition of Sn plating solution) Methanesulfonic acid Sn (as Sn ²⁺ ): 80g / L Methanesulfonic acid (as free acid): 150g / L Catechol: 1g / L Amine-based surfactant C1-3 : 5g / L non-ionic surfactant C2-4: 5g / L ion-exchanged water: the rest

<Examples 1-6 to 1-10, Examples 2-1, 2-2, 2-5 to 2-8, 2-11, 2-12, Comparative Examples 1-2, 1-3, 1-5 , 1-6, 1-9 to 1-11, Comparative Examples 2-1, 2-3 to 2-5, 2-7, 2-9 to 2-11, 2-13> Examples 1-6 to 1 -10, Examples 2-1, 2-2, 2-5 to 2-8, 2-11, 2-12, Comparative Examples 1-2, 1-3, 1-5, 1-6, 1-9 ~ 1-11, Comparative Examples 2-1, 2-3 ~ 2-5, 2-7, 2-9 ~ 2-11, 2-13, as amine-based surfactants (C1) and non-ionic interface activities The agent (C2 or C3) is a surfactant using the properties shown in Tables 1 to 3. Other than that, it performed similarly to Example 1, and the Sn plating liquid of the said Example and the said comparative example was built. However, Comparative Examples 1 to 11 did not use an amine surfactant (C1). Comparative Examples 2 to 13 did not use nonionic surfactants (C2 and / or C3).

(Building bath of SnAg plating solution) <Example 1-2> Methanesulfonic acid as a free acid, catechol as an antioxidant, thiourea as a complexing agent, and as After the benzaldehyde of the gloss agent is dissolved, the methanesulfonic acid Ag solution is further added and mixed. After mixing to form a homogeneous solution, a polycondensate of polyoxyethylene alkylamine (mass average molecular weight: 1300) of the above No. C1-4 and a polyoxyethylene and polyoxypropylene of the above C2-4 were further added as a surfactant. (Mass average molecular weight: 3100, EO group of polyalkyleneoxy group: PO group (Molar ratio) = 15:40). Finally, ion-exchanged water was added to create a SnAg plating solution having the following composition. However, the methanesulfonic acid Sn aqueous solution is prepared by electrolyzing a metal Sn plate in an methanesulfonic acid aqueous solution, and the methanesulfonic acid Ag aqueous solution is prepared by electrolyzing a metal Ag plate in an methanesulfonic acid aqueous solution.

(Composition of SnAg plating solution) Methanesulfonic acid Sn (as Sn ²⁺ ): 80g / L Methanesulfonic acid Ag (as Ag ⁺ ): 1.0g / L methanesulfonic acid (as free acid): 150g / L o-benzene Diphenol: 1g / L Thiourea: 2g / L Benzaldehyde: 0.01g / L Amine-based surfactant C1-4: 3g / L Non-ionic surfactant C2-4: 4g / L Ion-exchanged water: The rest

<Examples 1-4, 1-11, 1-13, 1-15, Examples 2-3, 2-9, Comparative Examples 1-1, 1-4, 1-8, Comparative Examples 2-6, 2 -12 ＞ Examples 1-4, 1-11, 1-13, 1-15, Examples 1-6, 2-12, Comparative Examples 1-1, 1-4, 1-8, Comparative Examples 2-6 2-12, as the surfactants, the surfactants having the properties shown in Tables 1 to 3 are used. Except that, it was performed in the same manner as in Example 1-2 to build the SnAg plating solution in the above-mentioned Examples and Comparative Examples.

(Building bath of SnCu plating solution) <Example 1-3> A methanesulfonic acid Sn aqueous solution was mixed with methanesulfonic acid as a free acid, catechol as an antioxidant, and thiourea as a complexing agent. After being dissolved, a Cu methanesulfonic acid solution was further added and mixed. After mixing to form a homogeneous solution, a polycondensate of polyoxyethylene alkylamine (mass average molecular weight: 650) of the above No. C1-6 and a polyoxyethylene and polyoxypropylene of the above C2-4 were further added as a surfactant. (Mass average molecular weight: 3100, EO group of polyalkyleneoxy group: PO group (Molar ratio) = 15:40). Finally, ion-exchanged water was added to prepare a SnCu plating solution having the following composition. However, the methanesulfonic acid Sn aqueous solution is prepared by electrolyzing a metal Sn plate in an methanesulfonic acid aqueous solution, and the Cu methanesulfonic acid aqueous solution is prepared by electrolyzing a metal Cu plate in an methanesulfonic acid aqueous solution.

(Composition of SnCu plating solution) Methanesulfonic acid Sn (as Sn ²⁺ ): 80g / L Methanesulfonic acid Cu (as Cu ²⁺ ): 0.5g / L Methanesulfonic acid (as free acid): 150g / L Hydroquinone: 1g / L Thiourea: 2g / L Amine-based surfactant C1-6: 3g / L Non-ionic surfactant C2-4: 3g / L Ion-exchanged water: The rest

<Examples 1-5, 1-12, 1-14, Examples 2-4, 2-10, Comparative Examples 1-7, Comparative Examples 2-2, 2-8> Examples 1-5, 1-12 , 1-14, Examples 2-4, 2-10, Comparative Examples 1-7, Comparative Examples 2-2, and 2-8. As the surfactants, surfactants having the properties shown in Tables 1 to 3 were used. . Other than that, it carried out similarly to Example 1-3, and built the SnCu plating liquid of the said Example and the said comparative example.

<Example 3-1> After mixing methanesulfonic acid as a free acid and catechol as an antioxidant in a methanesulfonic acid Sn aqueous solution to make a homogeneous solution, the above-mentioned No. as a surfactant was further added. C1-4 polyoxyethylene alkylamine (mass average molecular weight: 1300), the above-mentioned C2-4 polyoxyethylene and polyoxypropylene condensate (mass average molecular weight: 3100, polyalkyleneoxy EO group: PO (Molar ratio) = 15: 40), and the condensate of polyoxyethylene and polyoxypropylene with the above C3-4 (mass average molecular weight: 3100, EO group of polyalkylene oxide group: PO group (mole ratio ) = 15: 40). Finally, ion-exchanged water was added to prepare a Sn plating solution having the following composition. The methanesulfonic acid Sn aqueous solution is prepared by electrolyzing a metal Sn plate in an methanesulfonic acid aqueous solution.

(Composition of Sn plating solution) Methanesulfonic acid Sn (as Sn ²⁺ ): 80g / L Methanesulfonic acid (as free acid): 150g / L Catechol: 1g / L Amine-based surfactant C1-3 : 5g / L nonionic surfactant C2-4: 3g / L nonionic surfactant C3-4: 2g / L ion-exchanged water: the rest

<Example 3-2> After dissolving methanesulfonic acid as a free acid, catechol as an antioxidant, thiourea as a complexing agent, and benzaldehyde as a glossing agent, dissolved in an aqueous solution of methanesulfonic acid Sn. Then, further add the methanesulfonic acid Ag solution for mixing. After mixing to form a homogeneous solution, the polyoxyethylene alkylamine (mass average molecular weight: 1300) of the above No. C1-4, and the condensate of the polyoxyethylene and polyoxypropylene of the above C2-6 were further added as a surfactant. (Mass average molecular weight: 3400, EO group of polyalkyleneoxy group: PO group (molar ratio) = 20: 40), and condensate of polyoxyethylene and polyoxypropylene with the above C3-7 (mass average molecular weight: 3800, EO group of polyalkyleneoxy group: PO group (Molar ratio) = 30:40). Finally, ion-exchanged water was added to create a SnAg plating solution having the following composition. However, the methanesulfonic acid Sn aqueous solution is prepared by electrolyzing a metal Sn plate in an methanesulfonic acid aqueous solution, and the methanesulfonic acid Ag aqueous solution is prepared by electrolyzing a metal Ag plate in an methanesulfonic acid aqueous solution.

(Composition of SnAg plating solution) Methanesulfonic acid Sn (as Sn ²⁺ ): 80g / L Methanesulfonic acid Ag (as Ag ⁺ ): 1.0g / L methanesulfonic acid (as free acid): 150g / L o-benzene Diphenol: 1g / L Thiourea: 2g / L Benzaldehyde: 0.01g / L Amine-based surfactant C1-4: 3g / L Non-ionic surfactant C2-6: 2g / L Non-ionic surfactant C3-7: 2g / L ion-exchanged water: the rest

<Comparative test and evaluation> Use Examples 1-1 to 1-15, Examples 2-1 to 2-12, Comparative Examples 1-1 to 1-11, Comparative Examples 2-1 to 2-13, and Examples 3-1 ~ 3-2 three types of baths are used to form a plating film (bump), and the uniformity of the thickness of the plating film in the interior of the bare crystal (WID) and reflow soldering are evaluated. Porosity during the step. The results are shown in Tables 4 to 6.

(1) The uniformity of the plating film thickness in the bare wafer (WID). A seed layer for conductive layer (titanium 0.1 μm and copper 0.3 μm) was formed on the surface of the wafer (8 inches) by sputtering. ), And a dry film resist (film thickness: 50 μm) was laminated on the seed layer. Next, the dry film resist is locally exposed through the exposure mask, and then developed. As such, as shown in FIG. 1, an opening portion 2 having a diameter of 90 μm is formed on the surface of the wafer 1 to form patterned resists at different pitch intervals of a: 150 μm, b: 225 μm, and c: 375 μm.剂 层 3。 Agent layer 3.

The wafer 1 on which the resist layer 3 was formed was immersed in a plating apparatus (immersion type mixing and stirring apparatus), and the liquid temperature of the plating solution was 25 ° C., and the current density was 4 ASD, 8 ASD, and 12 ASD. To plate the openings 2 of the respective resist layers 3. Next, the wafer 1 is taken out from the plating apparatus, and after washing and drying, the resist layer 3 is peeled off using an organic solvent. In this way, a wafer with bumps is produced, which is a pattern in which bumps with a diameter of 90 μm are formed in a die at different pitch intervals of 150 μm, 225 μm, and 375 μm. The height of the bumps of the wafer was measured using an automatic visual inspection device. From the measured bump height, the uniformity of the plating film thickness in the inside of the bare crystal (WID) was calculated according to the following formula. The results are shown in the "WID" field in Table 1. WID = (maximum height-minimum height) / (2 × average height) × 100 Set the following conditions as the basis for the uniform plating film thickness: if the WID is 5 or less when the current density is 4ASD; When the WID is 8 or less when the current density is 8; When the WID is 20 or less when the current density is 12 ASD.

(2) Porosity generation The seed layer of the bump-attached wafer prepared in (1) above with a current density of 12 ASD is etched and removed, and then heated to 240 ° C. using a reflow device to make the bumps. Melting. After being left to cool, projections of a total of 2,000 bumps arranged at intervals of 150 μm, 225 μm, and 375 μm were taken for transmission X-ray imaging. Visually observe the photographed image, and set "NG" when the size of the pores to the size of the bumps is 1% or more, and if one or more such pores can be found, set "NG"; "OK". The results are shown in the "void" column of Tables 4 to 6.

As can be clearly understood from Tables 1 and 4, the y of the formula (1) of the amine surfactant (C1-1) of Comparative Examples 1-1 and 1-6 is 2 because it is not in the range of 4-12. Within this range, although no pores were found in the bumps, the WID in the current density range from 4 ASD to 12 ASD exceeded the reference, and the plating film thickness was uneven.

In the amine-based surfactant (C1-5) of Comparative Examples 1-2 and 1-7, y of formula (1) is 40. Since it is not in the range of 4-12, it spans from 4ASD to 12ASD. The WID in the current density range up to this point exceeds the reference, and the plating film thickness is uneven. Further, pores were also generated.

In the amine-based surfactant (C1-7) of Comparative Examples 1-3 and Comparative Examples 1-8, y of formula (1) is 40. Since it is not in the range of 4-12, it spans from 4ASD to 12ASD. The WID in the current density range up to this point exceeds the reference, and the plating film thickness is uneven. Further, pores were also generated.

In the amine-based surfactant (C1-8) of Comparative Examples 1-4 and Comparative Examples 1-9, the formula (1) has a y of 2. Since it is not in the range of 4 to 12, although no pores are found in the bumps, However, the WID in the current density range from 4 ASD to 12 ASD exceeded the reference, and the plating film thickness was uneven.

In the amine-based surfactant (C1-11) of Comparative Examples 1-5 and Comparative Examples 1-10, y of formula (1) is 40. Since it is not in the range of 4-12, it spans from 4ASD to 12ASD. The WID in the current density range up to this point exceeds the reference, and the plating film thickness is uneven. In Comparative Examples 1-5, no pores were found, but Comparative Examples 1-10 also had pores.

In Comparative Examples 1-11, only the non-ionic surfactant (C3-5) was used as the surfactant. Although no pores were found in the bumps, and the WID in the current densities of 4ASD and 8ASD were in accordance with the standard, the film was plated. The thickness is uniform, but at a current density of 12 ASD, the WID exceeds the reference, and the plating film thickness is uneven. That is, although the non-ionic surfactant (C2 or C3) has the suppressing effect required to suppress the variation in the height of the plating, the effect of promoting the supply of Sn ions in the elementary substance is low, so it will be high in the current density. Depletion of Sn ions is generated, which makes WID worse.

As is clear from Tables 2 and 5, the m of the EO group of the formula (2) of the nonionic surfactant (C2-1) of Comparative Example 2-1 is 10, and it is not in the range of 15 to 30. In addition, the PO group's n1 + n2 is 30 and is not in the range of 40 ~ 50. Although no pores are found in the bumps, the WID in the current density range from 4ASD to 12ASD is beyond the benchmark. , The plating film thickness is uneven.

In the nonionic surfactant (C2-2) of Comparative Example 2-2, n1 + n2 of the PO group of formula (2) is 40, and although it is in the range of 40 to 50, m of the EO group is 10, and It is not in the range of 15 to 30, so although no pores are found in the bumps, the WID in the current density range from 4 ASD to 12 ASD exceeds the reference, and the plating film thickness is uneven.

The m of the EO group of the formula (2) of the nonionic surfactant (C2-3) of Comparative Example 2-3 is 15, and although it is in the range of 15 to 30, n1 + n2 of the PO group is 30, and It is not in the range of 40 to 50, so although no pores are found in the bumps, the WID in the current density range from 4 ASD to 12 ASD exceeds the reference, and the plating film thickness is uneven.

In the non-ionic surfactant (C2-8) of Comparative Example 2-4, n1 + n2 of the PO group of the formula (2) is 50, and although it is in the range of 40 to 50, m of the EO group is 40, and It is out of the range of 15 to 30, so the WID in the current density range from 4 ASD to 12 ASD is beyond the reference, and the plating film thickness is uneven. Further, pores were also generated.

The m of the EO group of the formula (2) of the nonionic surfactant (C2-9) of Comparative Example 2-5 is 30, and although it is in the range of 15 to 30, n1 + n2 of the PO group is 60, and It is not in the range of 40 to 50, so the WID in the current density range from 4 ASD to 12 ASD is beyond the reference, and the plating film thickness is uneven. Further, pores were also generated.

The m of the EO group of the formula (2) of the nonionic surfactant (C2-10) of Comparative Example 2-6 is 50, which is not in the range of 15 to 30, and the n1 + n2 of the PO group is 60. It is not in the range of 40 to 50, so the WID in the current density range from 4 ASD to 12 ASD exceeds the reference, and the plating film thickness is uneven. Further, pores were also generated.

As is clear from Tables 3 and 5, the EO group of the formula (3) of the non-ionic surfactant (C3-1) of Comparative Examples 2-7 has m1 + m2 of 10, not 15 to 30. In the range, the n of the PO group is 30, and it is not in the range of 40 to 50. Although no pores are found in the bumps, the WID in the current density range from 4ASD to 12ASD is beyond the benchmark. , The plating film thickness is uneven.

In the nonionic surfactant (C3-2) of Comparative Example 2-8, the n of the PO group of formula (3) is 40, and although it is in the range of 40 to 50, m1 + m2 of the EO group is 10, and It is not in the range of 15 to 30, so although no pores are found in the bumps, the WID in the current density range from 4 ASD to 12 ASD exceeds the reference, and the plating film thickness is uneven.

The m1 + m2 of the EO group of the formula (3) of the nonionic surfactant (C3-3) of Comparative Example 2-9 is 15, although it is in the range of 15 to 30, n of the PO group is 30, and It is not in the range of 40 to 50, so although no pores are found in the bumps, the WID in the current density range from 4 ASD to 12 ASD exceeds the reference, and the plating film thickness is uneven.

The n of the PO group of the formula (3) of the nonionic surfactant (C3-8) of Comparative Example 2-10 is 50, and although it is in the range of 40 to 50, m1 + m2 of the EO group is 40, and It is out of the range of 15 to 30, so the WID in the current density range from 4 ASD to 12 ASD is beyond the reference, and the plating film thickness is uneven. Further, pores were also generated.

The m1 + m2 of the EO group of the formula (3) of the nonionic surfactant (C3-9) of Comparative Example 2-11 is 30, and although it is in the range of 15 to 30, n of the PO group is 60, and It is not in the range of 40 to 50, so the WID in the current density range from 4 ASD to 12 ASD is beyond the reference, and the plating film thickness is uneven. Further, pores were also generated.

In the nonionic surfactant (C3-10) of Comparative Example 2-12, m1 + m2 of the EO group of formula (3) is 50, which is not in the range of 15 to 30, and n of the PO group is 60. It is not in the range of 40 to 50, so the WID in the current density range from 4 ASD to 12 ASD exceeds the reference, and the plating film thickness is uneven. Further, pores were also generated.

The surfactant of Comparative Example 2-13 was only the amine surfactant (C1-4). Although no pores were found, the WID in the current density range from 4 ASD to 12 ASD exceeded the standard and was plated. The film thickness is uneven. That is, although the amine-based surfactant (C1) has the effect of promoting the supply of Sn ions, the suppressing effect required to suppress the height deviation of the plating cannot be obtained in the simple substance, and WID is high.

In comparison, Tables 4 to 6 clearly show that the amine-based interfaces of Examples 1-1 to 1-15, Examples 2-1 to 2-12, and Examples 3-1 to 3-2 The formula (1) of the active agents (C1-3), (C1-4), (C1-6), (C1-9), (C1-10) is in the range of 12 to 18, and y is in the range of 4 ~ 12, and non-ionic surfactants (C2-4), (C2-2), (C2-5), (C2-6), (C2-7), (C3-4), (C3-5), (C3-6), (C3-7) EO group: PO group (Mole ratio) m: n1 + n2 or m1 + m2: n is 15 ~ 30: 40 ~ 50 Therefore, no pores were found in the bumps, and the WID in the current density range from 4 ASD to 12 ASD was within the reference, and the plating film thickness was uniform. That is, by appropriately combining the amine-based surfactant (C1) and the non-ionic surfactant (C2 and / or C3), a WID that is good over a wide range of current densities from 4 to 12 ASD can be obtained, and Non-porous bumps. [Industrial availability]

The plating solution of the present invention can be used for electronic components such as printed substrates, flexible printed substrates, film carriers, semiconductor integrated circuits, resistors, capacitors, filters, inductors, thermistors, crystal oscillators, switches, wires, etc. And part of electronic components such as wafer bumps.

1‧‧‧ wafer

2‧‧‧ opening

3‧‧‧ resist layer

a‧‧‧Pitch interval: 150μm

b‧‧‧ pitch interval: 225μm

c‧‧‧Pitch interval: 375μm

[Fig. 1] A plan view of a wafer having a resist layer prepared in an example.

Claims (2)

A plating solution comprising (A) a soluble salt containing at least a stannous salt, (B) an acid or a salt thereof selected from an organic acid and an inorganic acid, and (C) an additive, characterized in that: The additive includes two types of surfactants, namely, an amine-based surfactant (C1) and a non-ionic surfactant (C2 and / or C3). The amine-based surfactant (C1) is a general formula (1) below. As the polyoxyethylene alkylamine, the nonionic surfactant (C2 or C3) is a condensate of polyoxyethylene and polyoxypropylene represented by the following general formula (2) or general formula (3), In formula (1), x is 12 to 18, and y is 4 to 12, Where in formula (2), m is 15 to 30, n1 + n2 is 40 to 50, In the formula (3), m1 + m2 is 15-30, and n is 40-50. For example, the plating solution of claim 1, wherein the additive further includes 2 of the surfactants (C1, C2, and / or C3), which are different from the surfactants, complexing agents, gloss agents, and antioxidants. More than one other additive.