Tin-silver plating solution for solder bumps

Abstract

One embodiment of the present invention provides a tin-silver plating solution and a method for forming tin-silver solder bumps using same. The tin-silver plating solution according to an embodiment of the present invention reduces whisker generation by using a novel silver complexing agent, a tin carrier, a grain refining agent, and a grain refining auxiliary agent, and maintains a uniform silver ion composition in the plating solution, thereby making the height of solder bumps uniform and allowing plating to be performed at a high speed.

Description

Tin-silver plating solution for solder bumps

[0001] The present invention relates to a tin-silver plating solution, and more particularly, to a tin-silver plating solution for solder bumps plated on a substrate of an electronic component including a semiconductor device.

[0002] The miniaturization and increased functionality of electronic devices like smartphones are driving demands for faster operation of core components like memory and increased electrode density. Consequently, flip-chip packaging technology is rapidly expanding. Conventional wire bonding involves connecting the chip and substrate with fine wiring. However, this method, which utilizes only the chip's edges, limits its ability to achieve high chip integration and improve electrical performance.

[0003] Meanwhile, the flip-chip packaging process forms solder bumps at intervals of tens of microns across the entire surface of the integrated circuit chip, and then directly bonds them to the circuit board by applying heat. This allows for a significant increase in the number of input / output terminals per unit area compared to the wire bonding method, making it applicable to fine pitch designs. Furthermore, because the length of the solder bumps is much shorter than that of the bonding wire, it offers superior electrical characteristics and component lifespan. Therefore, flip-chip technology can minimize package size, making it suitable for implementing lightweight, compact, high-performance, and high-speed electronic products, and it can also resolve issues such as noise. This technology can be expanded to not only CPUs and memories, but also the display field and the semiconductor industry as a whole.

[0004] These flip-chip packages come in various forms, but solder bumps are used, which are plated using a pure tin or tin-silver plating solution on a copper (or copper / nickel) pillar on a copper-based under bump metallurgy (UBM), and there is a need for the development of a plating solution for solder bumps to form uniform bumps with few voids.

[0005] Traditionally, tin-lead solder bumps have been widely used, boasting excellent soldering properties, low melting points, and ease of plating solution management. However, with the implementation of the RoHS law, which regulates the use of hazardous substances including lead, the use of tin-lead solder bumps has been restricted. Furthermore, whiskers frequently occur during the reflow process to create solder balls after plating solder bumps with tin plating solutions, and research to improve this has been continuously requested. Therefore, tin-based alloys such as tin-silver, tin-bismuth, tin-copper, and tin-zinc are being explored as alternatives to tin-lead alloys.

[0006] Among these, tin-silver alloys have attracted attention due to their advantages such as low resistivity, stability, ability to achieve a wide melting point range, and elimination of alpha particle emission by pure Sn sources. However, in the production of tin-silver solder bumps, silver ions (Ag) in the plating solution + ) tends to be deposited as a substitute for a specific UBM (under bump metal) layer or tin anode, so silver ions (Ag) in the plating solution + ) concentration control becomes difficult. In addition, if the tin-silver solder bump does not have an appropriate alloy composition ratio, whiskers or nodules may occur, which may cause interconnection reliability problems within the flip chip.

[0007] Another issue in the manufacture of the above-mentioned tin-silver solder bumps is the limited plating current density. While high current density during plating accelerates the bump plating speed, positively impacting high throughput, it can also lead to negative effects, such as difficulty in surface control and the formation of voids within the bump due to loose plating caused by excessive hydrogen gas generation from the plating electrode.

[0008] Therefore, there is a need to develop a tin-silver plating solution that has a stable plating speed and stable silver content under high-speed plating conditions and a smooth plating surface.

[0009] (Patent Document 1) Republic of Korea Patent Publication No. 10-1738535

[0010] (Patent Document 2) Republic of Korea Patent Publication No. 10-2023-0029380

[0011] (Patent Document 3) Republic of Korea Patent Publication No. 10-2016-0121296

[0012] The present invention seeks to provide a tin-silver plating solution for solder bumps for reducing whisker generation under high-speed plating and improving the non-uniformity of silver composition in solder, which solves the problems of the prior art described above.

[0013] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0014] In order to achieve the above technical task, one embodiment of the present invention provides a tin-silver plating solution.

[0015] A tin-silver plating solution according to one embodiment of the present invention comprises a tin ion source; silver ions (Ag +) source; and an organic additive; wherein the organic additive comprises a silver (Ag) complexing agent represented by the following <Chemical Formula 1>, a tin carrier, a grain refiner represented by the following <Chemical Formula 2>, and a grain refinement aid represented by the following <Chemical Formula 3>.

[0016] <Chemical Formula 1>

[0017]

[0018] In the above chemical formula 1,

[0019] R1 and R2 are each independently hydrogen, allyl having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, or a primary alcohol functional group having 1 to 6 carbon atoms containing a hydroxyl group,

[0020] <Chemical Formula 2>

[0021]

[0022] In the above chemical formula 2,

[0023] R4 is hydrogen; a linear alkyl having 1 to 7 carbon atoms; a branched alkyl having 5 to 20 carbon atoms; or a functional group containing an aromatic ring,

[0024] R5 is hydrogen; linear alkyl having 1 to 15 carbon atoms; branched alkyl having 5 to 20 carbon atoms; or linear alkyl having 2 to 7 carbon atoms including a hydroxyl group,

[0025] R6 is hydrogen; linear alkyl having 1 to 12 carbon atoms; or branched alkyl having 5 to 20 carbon atoms,

[0026] R7 is hydrogen; linear alkyl having 1 to 15 carbon atoms, or branched alkyl having 5 to 20 carbon atoms;

[0027] X is at least one selected from the group of ions consisting of chlorine (Cl), bromine (Br), iodine (I), nitrate (NO3), sulfate (SO4), carbonate (CO3), and hydroxyl (OH),

[0028] <Chemical Formula 3>

[0029]

[0030] In the above chemical formula 3,

[0031] R8 is alkyl having 2 to 10 carbon atoms,

[0032] R9 is a hydrocarbon linking group having 2 to 10 carbon atoms,

[0033] R 10 is a hydrocarbon linking group containing an aromatic ring,

[0034] R 11 It is a polymer having 3 to 70 repeating groups composed of at least one of ethylene, propylene, and butylene, and includes hydrogen, sulfonate, or phosphonate as a terminal group.

[0035] In an embodiment of the present invention, the tin carrier may be a tin-silver plating solution characterized by the following <Chemical Formula 4>.

[0036] <Chemical Formula 4>

[0037]

[0038] In the above chemical formula 4,

[0039] A is a substituted or unsubstituted C6 to C30 aryl group or a heteroaryl having 6 to 30 ring atoms, wherein at least one ring carbon contains a heteroatom composed of at least one of nitrogen, oxygen and sulfur,

[0040] R3 is any one of hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a hydroxy group, a sulfonate group ionically bonded with an alkali metal cation, a phosphonate group ionically bonded with an alkali metal cation, a nitronate group ionically bonded with an alkali metal cation, and a chlorate group ionically bonded with an alkali metal cation.

[0041] n1 to n4 are each independently integers from 0 to 26, and the sum of n1 to n4 is from 10 to 26.

[0042] In an embodiment of the present invention, R of the above <chemical formula 3> 10 The tin-silver plating solution may be characterized by being any one selected from the group consisting of Benzene, Biphenyl, Furan, Imidazole, Indazole, Indole, Indolizine, Isoindole, Isooxazole, Isoquinoline, Naphthalene, Oxazole, Phenalene, Pyran, Pyrazine, Pyrazole, Pyridazine, Pyridine, Pyrimidine, Pyrrole, Pyrrolizine, Quinazoline, Quinoline, and Thiophene.

[0043] In an embodiment of the present invention, the tin-silver plating solution may be characterized in that tin ions and silver ions in the tin-silver plating solution are provided in a weight ratio of 75:25 to 99.9:0.1.

[0044] In an embodiment of the present invention, the tin ion source may be a tin-silver plating solution characterized in that it includes at least one water-soluble tin compound selected from the group consisting of tin sulfate, tin hydrochloride, tin sulfamate, tin acetate, tin phosphate, tin methanesulfonate, tin gluconate, and tin carbonate.

[0045] In an embodiment of the present invention, the silver ion (Ag + ) The source may be a tin-silver plating solution characterized in that it contains at least one water-soluble silver (Ag) compound selected from the group consisting of silver sulfuric acid, silver hydrochloric acid, silver sulfamic acid, silver acetic acid, silver phosphate, silver methanesulfonic acid, silver gluconic acid, and silver carboxylic acid.

[0046] In an embodiment of the present invention, the silver ion (Ag + ) The tin-silver plating solution may be characterized in that the silver (Ag) complexing agent is provided in a molar ratio of 1:1 to 1:10 relative to the supply source.

[0047] In an embodiment of the present invention, the tin-silver plating solution may be characterized by further including at least one of an electrolyte, an antioxidant, and a leveling agent.

[0048] In an embodiment of the present invention, the electrolyte may be a tin-silver plating solution characterized by being either a hydroxycarboxylic acid or an alkanesulfonic acid.

[0049] In an embodiment of the present invention, the antioxidant may be a tin-silver plating solution characterized in that at least one selected from the group consisting of catechol, hydroquinone, resorcinol, cresol, phloroglucinol, oxyhydroquinone, and pyrogallol.

[0050] In an embodiment of the present invention, the leveling agent may be a tin-silver plating solution characterized in that at least one selected from the group consisting of a nonionic interface activator, a cationic interface activator, an anionic interface activator, and a synthetic polymer.

[0051] In order to achieve the above technical task, another embodiment of the present invention provides a method for forming a tin-silver solder bump.

[0052] A method for forming a tin-silver solder bump according to one embodiment of the present invention comprises: a tin ion source; silver ions (Ag + ) source; and an organic additive; wherein the organic additive comprises a silver (Ag) complexing agent represented by the following <Chemical Formula 1>, a tin carrier, a grain refiner represented by the following <Chemical Formula 2>, and a grain refinement aid represented by the following <Chemical Formula 3>; a step of exposing a lower bump metal structure to a plating bath containing a tin-silver plating solution; and a step of applying a current to plate a tin-silver alloy on the lower bump metal structure.

[0053] <Chemical Formula 1>

[0054]

[0055] In the above chemical formula 1,

[0056] R1 and R2 are each independently hydrogen, allyl having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, or a primary alcohol functional group having 1 to 6 carbon atoms containing a hydroxyl group,

[0057] <Chemical Formula 2>

[0058]

[0059] In the above chemical formula 2,

[0060] R4 is hydrogen; a linear alkyl having 1 to 7 carbon atoms; a branched alkyl having 5 to 20 carbon atoms; or a functional group containing an aromatic ring,

[0061] R5 is hydrogen; linear alkyl having 1 to 15 carbon atoms; branched alkyl having 5 to 20 carbon atoms; or linear alkyl having 2 to 7 carbon atoms including a hydroxyl group,

[0062] R6 is hydrogen; linear alkyl having 1 to 12 carbon atoms; or branched alkyl having 5 to 20 carbon atoms,

[0063] R7 is hydrogen; linear alkyl having 1 to 15 carbon atoms, or branched alkyl having 5 to 20 carbon atoms;

[0064] X is at least one selected from the group of ions consisting of chlorine (Cl), bromine (Br), iodine (I), nitrate (NO3), sulfate (SO4), carbonate (CO3), and hydroxyl (OH),

[0065] <Chemical Formula 3>

[0066]

[0067] In the above chemical formula 3,

[0068] R8 is alkyl having 2 to 10 carbon atoms,

[0069] R9 is a hydrocarbon linking group having 2 to 10 carbon atoms,

[0070] R 10 is a hydrocarbon linking group containing an aromatic ring,

[0071] R 11 It is a polymer having 3 to 70 repeating groups composed of at least one of ethylene, propylene, and butylene, and includes hydrogen, sulfonate, or phosphonate as a terminal group.

[0072] In an embodiment of the present invention, a method for forming a tin-silver solder bump may be provided, characterized in that in the step of plating the tin-silver alloy, the applied current has a current density of 1 ASD to 10 ASD.

[0073] Another embodiment of the present invention for achieving the above technical task provides a tin-silver solder bump formed by the method for forming the tin-silver solder bump.

[0074] Even when high-speed plating is performed using a tin-silver plating solution according to an embodiment of the present invention, the occurrence of whiskers is reduced, and the silver ion composition in the tin-silver plating solution can be maintained uniformly. Accordingly, there is an effect of enabling the formation of an excellent flip-chip package that minimizes defects in the plating film structure, such as cracks in the intermetallic compound layer within the solder bump, underplating of the plating film, and voids (empty spaces within the bump).

[0075] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the composition of the invention described in the claims.

[0076] Figure 1 is a scanning electron microscope image of a tin-silver plating film resultant using the plating solution of Manufacturing Example 2 of the present invention.

[0077] Figure 2 is a scanning electron microscope image of a tin-silver plating film resultant using the plating solution of Manufacturing Example 3 of the present invention.

[0078] Figure 3 is a scanning electron microscope image of the tin-silver plating film result using the plating solution of Manufacturing Example 4 of the present invention.

[0079] Figure 4 is a scanning electron microscope image of a tin-silver plating film resultant using the plating solution of Manufacturing Example 5 of the present invention.

[0080] Figure 5 is a scanning electron microscope image of a tin-silver plating film resultant using the plating solution of Manufacturing Example 6 of the present invention.

[0081] Figure 6 is a scanning electron microscope image of the tin-silver plating film result using the plating solution of Manufacturing Example 7 of the present invention.

[0082] Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention can be implemented in various different forms and is therefore not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity of description, and similar parts have been designated with similar reference numerals throughout the specification.

[0083] Throughout the specification, when a part is said to be "connected (connected, contacted, or coupled)" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly connected" with another part in between. Furthermore, when a part is said to "include" a component, this does not exclude other components, but rather implies that it may include other components, unless otherwise specifically stated.

[0084] The terminology used herein is merely used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0085] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0086]

[0087] A tin-silver plating solution according to one embodiment of the present invention is described.

[0088] A tin-silver plating solution according to one embodiment of the present invention comprises a tin ion source, silver ions (Ag+ ) characterized by including a supply source and organic additives.

[0089] As regulations regarding environmental concerns related to lead have become more stringent in recent years, interest in lead-free solders has increased, and pure tin, tin-copper, tin-silver, and ternary tin alloys have been explored as potential alternatives to conventional tin-lead alloys.

[0090] Among them, in particular, the tin-silver alloy has the advantages of low resistance, stability, and a wide melting point, and has superior mechanical properties such as tensile strength, thermal fatigue, and creep compared to the tin-lead alloy, and has the advantage of particularly excellent joint strength.

[0091] The tin-silver plating solution of the present invention is for manufacturing a solder bump including the above-described tin-silver alloy, and comprises a tin ion supply source and silver ions (Ag + ) includes the source of supply.

[0092] In one embodiment of the present invention, the tin ion supply source is tin ions (Sn) in the tin-silver plating solution of the present invention. 2+ ) as a material supplying the water-soluble tin compound, and the water-soluble tin compound may be, for example, one or more selected from the group consisting of tin sulfate, tin hydrochloride, tin sulfamate, tin acetate, tin phosphate, tin methanesulfonate, tin gluconate, and tin carbonate, for example, tin methanesulfonate having high solubility.

[0093] In one embodiment of the present invention, the silver ion (Ag + ) The source is silver ions (Ag) in the tin-silver plating solution of the present invention. + )(Ag - ) as a material supplying the silver compound, which may be a water-soluble silver compound, and the water-soluble silver compound may include, for example, one or more selected from the group consisting of silver sulfate, silver hydrochloride, silver sulfamate, silver acetate, silver phosphate, silver methanesulfonic acid, silver gluconic acid, and silver carboxylic acid, for example, silver methanesulfonic acid.

[0094] In one embodiment of the present invention, tin ions and silver ions (Ag) in the tin-silver plating solution ) can be provided in a weight ratio of 75:25 to 99.9:0.1, and the tin ion source and silver ion (Ag + ) The source is the above tin ion and silver ion (Ag + ) can be provided so that it can be provided at the above weight ratio.

[0095] Tin ions and silver ions (Ag) in the above range + ) when forming a tin-silver solder bump using a tin-silver plating solution having a weight ratio of 100 to 1000, solderability can be good. On the other hand, when tin ions and silver ions (Ag + ) is outside the above range, problems such as the occurrence of whiskers in the plating process and the increase in melting temperature in the reflow process may occur during the formation of the tin-silver solder bump.

[0096]

[0097] Next, the organic additives included in one embodiment of the present invention include (1) a silver (Ag) complexing agent, (2) a tin carrier, (3) a grain refiner, and (4) a grain refinement aid, and may further include other additional organic compounds.

[0098] In one embodiment of the present invention, the silver (Ag) complexing agent included in the organic additive may be a compound represented by the following <Chemical Formula 1>.

[0099] <Chemical Formula 1>

[0100]

[0101] In the above chemical formula 1,

[0102] R1 and R2 are each independently hydrogen, allyl having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, or a primary alcohol functional group having 1 to 6 carbon atoms and including a hydroxyl group.

[0103] The silver-silver plating solution can form a whisker structure or an Ag3Sn phase with a high melting point, which can impair the characteristics of the solder bump, depending on the change in the composition of silver (Ag), so precise control of the silver (Ag) composition is required.

[0104] The control of the above silver (Ag) composition is achieved by mixing tin ions and silver ions (Ag + ) is very large and silver precipitation occurs when used for a long time, which shortens the life of the plating solution, causing difficulties.

[0105] Silver ion (Ag+)(Ag + ) and tin ions (Sn 2+ ) The reduction potential is as shown in the following reaction scheme 1:

[0106] [Reaction Formula 1]

[0107] Ag + + e → Ag E0= +0.8 V

[0108] Sn 2+ + 2e → Sn E0= -0.14 V

[0109] In one embodiment of the present invention, when plating using a tin-silver plating solution, silver ions (Ag + ) is exposed to tin ions or under-bump-metallurgy (UBM), it can spontaneously oxidize the tin ions or the under-bump metal, and at the same time be reduced to silver (Ag) and precipitated.

[0110] The above-deposited silver (Ag) can be finely separated silver (Ag) metal floating in the plating solution or can be spontaneously deposited on the substrate, the wall of the plating bath, and the electrode, which is silver ions (Ag) in the plating solution. + ) can make it difficult to control the concentration.

[0111] Therefore, by preventing the precipitation of silver (Ag) during plating using a tin-silver plating solution, stability is improved, and tin ions and silver ions (Ag) are +) to minimize the error range of the silver composition of the tin-silver solder, and the silver (Ag) complexing agent prevents the precipitation of silver to improve stability and to reduce the reduction potential difference between tin ions and silver ions (Ag + ) can play a role in minimizing the silver composition error range of tin-silver solder by reducing the reduction potential difference.

[0112] In one embodiment of the present invention, the silver ion (Ag + ) The silver (Ag) complexing agent can be provided in a molar ratio of 1:1 to 1:10 compared to the supply source.

[0113]

[0114] In one embodiment of the present invention, the crystal grain refiner included in the organic additive may be a compound represented by the following <Chemical Formula 2>.

[0115] <Chemical Formula 2>

[0116]

[0117] In the above chemical formula 2,

[0118] R4 is hydrogen; a linear alkyl having 1 to 7 carbon atoms; a branched alkyl having 5 to 20 carbon atoms; or a functional group containing an aromatic ring,

[0119] R5 is hydrogen; linear alkyl having 1 to 15 carbon atoms; branched alkyl having 5 to 20 carbon atoms; or linear alkyl having 2 to 7 carbon atoms including a hydroxyl group,

[0120] R6 is hydrogen; linear alkyl having 1 to 12 carbon atoms; or branched alkyl having 5 to 20 carbon atoms,

[0121] R7 is hydrogen; linear alkyl having 1 to 15 carbon atoms, or branched alkyl having 5 to 20 carbon atoms;

[0122] X is at least one selected from the group of ions consisting of chlorine (Cl), bromine (Br), iodine (I), nitrate (NO3), sulfate (SO4), carbonate (CO3), and hydroxyl (OH),

[0123]

[0124] In one embodiment of the present invention, when tin-silver plating is performed on a lower bump metal, for example, copper, an intermetallic compound (IMC) may be generated during a heating process after the tin plating, which may cause whiskers to form due to stress caused by thermal expansion. Specifically, stress may be generated due to the formation of the IMC, direct mechanical stress such as tension or compression, thermomechanical stress caused by a difference in thermal expansion coefficient, surface oxidation, etc., which may cause whisker growth.

[0125] In one embodiment of the present invention, the crystal grain refiner included in the organic additive can suppress whisker growth by reducing the internal stress of the tin plating layer through suppressing the growth of a copper and tin intermetallic compound by making the crystal grain size of the tin-silver plating film smaller.

[0126]

[0127] In one embodiment of the present invention, the crystal grain refinement aid included in the organic additive may be a compound represented by the following <Chemical Formula 3>.

[0128] <Chemical Formula 3>

[0129]

[0130] In the above chemical formula 3,

[0131] R8 is alkyl having 2 to 10 carbon atoms,

[0132] R9 is a hydrocarbon linking group having 2 to 10 carbon atoms,

[0133] R 10 is a hydrocarbon linking group containing an aromatic ring,

[0134] R 11It is a polymer having 3 to 70 repeating groups composed of at least one of ethylene, propylene, and butylene, and includes hydrogen, sulfonate, or phosphonate as a terminal group.

[0135] In one embodiment of the present invention, the grain refinement aid included in the organic additive improves the wettability of the plating solution, thereby assisting the grain refinement agent to function smoothly from the beginning to the end of plating.

[0136] In an embodiment of the present invention, the tin carrier may be a tin-silver plating solution characterized by the following <Chemical Formula 4>.

[0137] <Chemical Formula 4>

[0138]

[0139] In the above chemical formula 4,

[0140] A is a substituted or unsubstituted C6 to C30 aryl group or a heteroaryl having 6 to 30 ring atoms, wherein at least one ring carbon contains a heteroatom composed of at least one of nitrogen, oxygen and sulfur,

[0141] R3 is any one of hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a hydroxy group, a sulfonate group ionically bonded with an alkali metal cation, a phosphonate group ionically bonded with an alkali metal cation, a nitronate group ionically bonded with an alkali metal cation, and a chlorate group ionically bonded with an alkali metal cation.

[0142] n1 to n4 are each independently integers from 0 to 26, and the sum of n1 to n4 is from 10 to 26.

[0143] In addition, the tin-silver plating solution, which is an embodiment of the present invention, may further include at least one of an electrolyte, an antioxidant, and a leveling agent as an organic additive.

[0144] In one embodiment of the present invention, the electrolyte serves to maintain the pH of the tin-silver plating solution and provide electrical conductivity, and the electrolyte may be selected from at least one selected from the group consisting of hydroxy carboxylic acid and alkane sulfonic acid, but is not limited thereto, and may be, for example, at least one selected from the group consisting of methanesulfonic acid, ethanesulfonic acid, and propanesulfonic acid, for example, methanesulfonic acid.

[0145] The above electrolyte may be included in an amount of 5 wt% to 30 wt% based on 100 wt% of the tin-silver plating solution. If the conductive salt is included in an amount of less than 5 wt%, the plating solution may not be sufficiently electrically conductive, which may result in a decrease in the plating speed. If the conductive salt is included in an amount of more than 30 wt%, it may be difficult to control the plating shape.

[0146]

[0147] *In one embodiment of the present invention, the antioxidant is used to minimize or prevent the oxidation of divalent tin ions (Sn2+) into tetravalent tin ions (Sn4+) and to help maintain the divalent tin ions (Sn2+). The antioxidant may be selected from one or more polyhydroxy aromatic compounds, but is not limited thereto. For example, the antioxidant may be at least one selected from the group consisting of catechol, hydroquinone, resorcinol, cresol, phloroglucinol, oxyhydroquinone, and pyrogallol.

[0148] The content of the above antioxidant may be 0.01 g / L to 20 g / L, and when the content of the above antioxidant is less than 0.01 g / L, the plating solution may contain tin ions (Sn) in the amount of 4. 4+ ) increases, the life of the plating solution becomes shorter, and if it exceeds 20 g / L, the uniformity and smoothness of the solder may deteriorate.

[0149] In one embodiment of the present invention, the smoothing agent improves the wettability of the solution during plating, thereby improving the ability of the liquid to wet even fine patterns or narrow spaces and broadening the working range. The smoothing agent may be selected from the group consisting of a nonionic interface activator, a cationic interface activator, an anionic interface activator, and a synthetic polymer, but is not limited thereto. For example, the smoothing agent may be any one of a nonionic interface activator, for example, 2-naphthyl ethyl ether, polyoxyalkylene ether, polyoxyethylene glycol, polyoxyethylene alkylphenyl ether, and polyoxyethylene alkyl amino ether.

[0150]

[0151] Another embodiment of the present invention provides a method for forming a tin-silver solder bump.

[0152] FIG. 1 is a flowchart schematically illustrating a method for forming a tin-silver solder bump according to one embodiment of the present invention.

[0153] A method for forming a tin-silver solder bump according to an embodiment of the present invention comprises the steps of: supplying a tin ion source; supplying silver ions (Ag) as shown in FIG. 1; +) source; and an organic additive; wherein the organic additive comprises a silver (Ag) complexing agent represented by the following <Chemical Formula 1>, a tin carrier, a grain refiner represented by the following <Chemical Formula 2>, and a grain refinement aid represented by the following <Chemical Formula 3>; a step of exposing a lower bump metal structure to a plating bath containing a tin-silver plating solution; and a step of applying a current to plate a tin-silver alloy on the lower bump metal structure.

[0154] <Chemical Formula 1>

[0155]

[0156] In the above chemical formula 1,

[0157] R1 and R2 are each independently hydrogen, allyl having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, or a primary alcohol functional group having 1 to 6 carbon atoms containing a hydroxyl group,

[0158] <Chemical Formula 2>

[0159]

[0160] In the above chemical formula 2,

[0161] R4 is hydrogen; a linear alkyl having 1 to 7 carbon atoms; a branched alkyl having 5 to 20 carbon atoms; or a functional group containing an aromatic ring,

[0162] R5 is hydrogen; linear alkyl having 1 to 15 carbon atoms; branched alkyl having 5 to 20 carbon atoms; or linear alkyl having 2 to 7 carbon atoms including a hydroxyl group,

[0163] R6 is hydrogen; linear alkyl having 1 to 12 carbon atoms; or branched alkyl having 5 to 20 carbon atoms,

[0164] R7 is hydrogen; linear alkyl having 1 to 15 carbon atoms, or branched alkyl having 5 to 20 carbon atoms;

[0165] X is at least one selected from the group of ions consisting of chlorine (Cl), bromine (Br), iodine (I), nitrate (NO3), sulfate (SO4), carbonate (CO3), and hydroxyl (OH),

[0166] <Chemical Formula 3>

[0167]

[0168] In the above chemical formula 3,

[0169] R8 is alkyl having 2 to 10 carbon atoms,

[0170] R9 is a hydrocarbon linking group having 2 to 10 carbon atoms,

[0171] R 10 is a hydrocarbon linking group containing an aromatic ring,

[0172] R 11 It is a polymer having 3 to 70 repeating groups composed of at least one of ethylene, propylene, and butylene, and includes hydrogen, sulfonate, or phosphonate as a terminal group.

[0173] In the step of plating the above tin-silver alloy, the applied current may have a current density of 1 ASD to 10 ASD.

[0174] Another embodiment of the present invention for achieving the above technical task provides a tin-silver solder bump formed by the method for forming the tin-silver solder bump.

[0175]

[0176] Hereinafter, the present invention will be described in more detail through manufacturing examples, examples, and experimental examples. However, the present invention is not limited to the following manufacturing examples, examples, and experimental examples.

[0177]

[0178] Manufacturing Example 1: Copper-plated silicon wafer

[0179] Electroplating was performed on a silicon wafer having a pattern using a copper plating solution with a thickness of 10 μm.

[0180] At this time, the copper plating solution was prepared by adding 50 g of copper ions, 150 g of sulfate ions, 50 mg of chlorine ions per 1 L of the plating solution, a polyethylene oxide derivative containing an aromatic hydrocarbon as an inhibitor, an organic compound containing a mercapto group as an accelerator, and a saturated heterocyclic compound containing nitrogen as a leveling agent, and the electroplating was performed by applying current for 10 minutes at a current density of 5 ASD.

[0181]

[0182] Manufacturing Example 2: Manufacturing of Plating Solution 1

[0183] Tin methanesulfonate and silver methanesulfonate were mixed to obtain 50.0 g / L of tin ions (Sn 2+ ), 0.5g / L of silver ions (Ag + ), a plating solution containing 120 g / L of methanesulfonic acid ions was prepared.

[0184] As an organic additive, a tin carrier was added at 40 g / l of a compound in which A in chemical formula 4 is a phenyl group, R3 is a hydroxyl group, n1 to n3 are each 0, and n4 is 12, and 2 g / l of catechol was added as an antioxidant.

[0185] Additionally, 5 g / l of a silver complexing agent having a structure of the following chemical formula 1a and 1.8 g / l of a crystal grain refiner having a structure of the following chemical formula 2a were further added.

[0186] Chemical formula 1a: Dibutyl thiourea

[0187] Formula 2a: Triethyl Benzyl Ammonium Chloride

[0188]

[0189] Manufacturing Example 3: Manufacturing of Plating Solution 2

[0190] Tin methanesulfonate and silver methanesulfonate were mixed to obtain 50.0 g / L of tin ions (Sn 2+ ), 0.5g / L of silver ions (Ag + ), a plating solution containing 120 g / L of methanesulfonic acid ions was prepared.

[0191] As an organic additive, a tin carrier was added at 40 g / l of a compound in which A in chemical formula 4 is a phenyl group, R3 is a hydroxyl group, n1 to n3 are each 0, and n4 is 12, and 2 g / l of catechol was added as an antioxidant.

[0192] Additionally, 8 g / l of a silver complexing agent having the structure of the following chemical formula 1b and 1.8 g / l of a crystal grain refiner having the structure of the above chemical formula 2a were further added.

[0193] Chemical Formula 1b: N-Allylthiourea

[0194]

[0195] Manufacturing Example 4: Manufacturing of Plating Solution 3

[0196] Tin methanesulfonate and silver methanesulfonate were mixed to obtain 50.0 g / L of tin ions (Sn 2+ ), 0.5g / L of silver ions (Ag + ), a plating solution containing 120 g / L of methanesulfonic acid ions was prepared.

[0197] As an organic additive, a tin carrier was added at 40 g / l of a compound in which A in chemical formula 4 is a phenyl group, R3 is a hydroxyl group, n1 to n3 are each 0, and n4 is 12, and 2 g / l of catechol was added as an antioxidant.

[0198] Additionally, 5 g / l of a silver complexing agent having the structure of the above chemical formula 1a, 1.8 g / l of a crystal grain refiner having the structure of the above chemical formula 2a, and 2 g / l of a crystal grain refiner auxiliary agent having the structure of the following chemical formula 3a were further added.

[0199] Chemical formula 3a: trimethylhexane phenol ethoxylate (40)

[0200]

[0201] Manufacturing Example 5: Manufacturing of Plating Solution 4

[0202] Tin methanesulfonate and silver methanesulfonate were mixed to obtain 50.0 g / L of tin ions (Sn 2+ ), 0.5g / L of silver ions (Ag + ), a plating solution containing 120 g / L of methanesulfonic acid ions was prepared.

[0203] As an organic additive, a tin carrier was added at 40 g / l of a compound in which A in chemical formula 4 is a phenyl group, R3 is a hydroxyl group, n1 to n3 are each 0, and n4 is 12, and 2 g / l of catechol was added as an antioxidant.

[0204] Additionally, 8 g / l of a silver complexing agent having the structure of the above chemical formula 1b, 1.8 g / l of a crystal grain refiner having the structure of the above chemical formula 2a, and 2 g / l of a crystal grain refiner auxiliary agent having the structure of the above chemical formula 3a were further added.

[0205]

[0206] Manufacturing Example 6: Manufacturing of Plating Solution 5

[0207] Tin methanesulfonate and silver methanesulfonate were mixed to obtain 50.0 g / L of tin ions (Sn 2+ ), 0.5g / L of silver ions (Ag + ), a plating solution containing 120 g / L of methanesulfonic acid ions was prepared.

[0208] As an organic additive, a tin carrier was added at 40 g / l of a compound in which A in chemical formula 4 is a phenyl group, R3 is a hydroxyl group, n1 to n3 are each 0, and n4 is 12, and 2 g / l of catechol was added as an antioxidant.

[0209] Additionally, 5 g / l of a silver complexing agent having the structure of the above chemical formula 1a, 1.8 g / l of a crystal grain refiner having the structure of the above chemical formula 2a, and 3.5 g / l of a crystal grain refiner auxiliary agent having the structure of the following chemical formula 3b were further added.

[0210] Formula 3b: Dipotassium trimethylhexane phenol ethoxylate(5) phosphate

[0211]

[0212] Manufacturing Example 7: Manufacturing of Plating Solution 6

[0213] Tin methanesulfonate and silver methanesulfonate were mixed to obtain 50.0 g / L of tin ions (Sn 2+ ), 0.5g / L of silver ions (Ag + ), a plating solution containing 120 g / L of methanesulfonic acid ions was prepared.

[0214] As an organic additive, a tin carrier was added at 40 g / l of a compound in which A in chemical formula 4 is a phenyl group, R3 is a hydroxyl group, n1 to n3 are each 0, and n4 is 12, and 2 g / l of catechol was added as an antioxidant.

[0215] Additionally, 8 g / l of a silver complexing agent having the structure of the above chemical formula 1b, 1.8 g / l of a crystal grain refiner having the structure of the above chemical formula 2a, and 3.5 g / l of a crystal grain refiner auxiliary agent having the structure of the above chemical formula 3b were further added.

[0216]

[0217] Experimental Example 1: Performance Evaluation of Tin-Silver Plating Solution 1 (Manufacturing Example 2)

[0218] In this Experimental Example 1, a plating performance test was conducted on a tin-silver plating solution containing only a silver complexing agent corresponding to Chemical Formula 1a and a crystal grain refiner corresponding to Chemical Formula 2a using the above Manufacturing Example 2.

[0219] The silicon wafer having the lower bump metal structure of the above Manufacturing Example 1 formed was immersed in the tin plating solution prepared in the above Manufacturing Example 2, and tin-silver plating was performed by applying a current density of 5ASD.

[0220] Figure 1 is a scanning electron microscope image of a tin-silver plating film resultant using the plating solution of Manufacturing Example 2 of the present invention.

[0221] The surface SEM image of the resulting tin-silver solder bump is shown in Fig. 1, and the surface roughness results are shown in Table 1 below.

[0222]

[0223] Experimental Example 2: Performance Evaluation of Tin-Silver Plating Solution 2 (Manufacturing Example 3)

[0224] In this Experimental Example 2, a plating performance test was conducted on a tin-silver plating solution containing only a silver complexing agent corresponding to Chemical Formula 1b and a crystal grain refiner corresponding to Chemical Formula 2a using the above Manufacturing Example 3.

[0225] The silicon wafer having the lower bump metal structure of the above Manufacturing Example 1 formed thereon was immersed in the tin plating solution prepared in the above Manufacturing Example 3, and tin-silver plating was performed by applying a current density of 5ASD.

[0226] Figure 2 is a scanning electron microscope image of a tin-silver plating film resultant using the plating solution of Manufacturing Example 3 of the present invention.

[0227] The surface SEM image of the resulting tin-silver solder bump is shown in Fig. 2, and the surface roughness results are shown in Table 1 below.

[0228]

[0229] Experimental Example 3: Performance Evaluation of Tin-Silver Plating Solution 3 (Manufacturing Example 4)

[0230] In this Experimental Example 3, a plating performance test was conducted on a tin-silver plating solution containing a silver complexing agent corresponding to Chemical Formula 1a, a crystal grain refiner corresponding to Chemical Formula 2a, and a crystal grain refinement aid corresponding to Chemical Formula 3a using the above Manufacturing Example 4.

[0231] The silicon wafer having the lower bump metal structure of the above Manufacturing Example 1 formed was immersed in the tin plating solution prepared in the above Manufacturing Example 4, and tin-silver plating was performed by applying a current density of 5ASD.

[0232] Figure 3 is a scanning electron microscope image of the tin-silver plating film result using the plating solution of Manufacturing Example 4 of the present invention.

[0233] The surface SEM image of the resulting tin-silver solder bump is shown in Fig. 3, and the surface roughness results are shown in Table 1 below.

[0234]

[0235] Experimental Example 4: Performance Evaluation of Tin-Silver Plating Solution 4 (Manufacturing Example 5)

[0236] In this Experimental Example 4, a plating performance test was conducted on a tin-silver plating solution containing a silver complexing agent corresponding to Chemical Formula 1b, a crystal grain refiner corresponding to Chemical Formula 2a, and a crystal grain refinement aid corresponding to Chemical Formula 3a using the above Manufacturing Example 5.

[0237] The silicon wafer having the lower bump metal structure of the above Manufacturing Example 1 formed thereon was immersed in the tin plating solution prepared in the above Manufacturing Example 5, and tin-silver plating was performed by applying a current density of 5ASD.

[0238] Figure 4 is a scanning electron microscope image of a tin-silver plating film resultant using the plating solution of Manufacturing Example 5 of the present invention.

[0239] The surface SEM image of the resulting tin-silver solder bump is shown in Fig. 4, and the surface roughness results are shown in Table 1 below.

[0240]

[0241] Experimental Example 5: Performance Evaluation of Tin-Silver Plating Solution 5 (Manufacturing Example 6)

[0242] In this Experimental Example 5, a plating performance test was conducted on a tin-silver plating solution containing a silver complexing agent corresponding to Chemical Formula 1a, a crystal grain refiner corresponding to Chemical Formula 2a, and a crystal grain refinement aid corresponding to Chemical Formula 3b using the above Manufacturing Example 6.

[0243] The silicon wafer having the lower bump metal structure of the above Manufacturing Example 1 formed was immersed in the tin plating solution prepared in the above Manufacturing Example 6, and tin-silver plating was performed by applying a current density of 5ASD.

[0244] Figure 5 is a scanning electron microscope image of a tin-silver plating film resultant using the plating solution of Manufacturing Example 6 of the present invention.

[0245] The surface SEM image of the resulting tin-silver solder bump is shown in Fig. 5, and the surface roughness results are shown in Table 1 below.

[0246]

[0247] Experimental Example 6: Performance Evaluation of Tin-Silver Plating Solution 6 (Manufacturing Example 7)

[0248] In this Experimental Example 6, a plating performance test was conducted on a tin-silver plating solution containing a silver complexing agent corresponding to Chemical Formula 1b, a grain refiner corresponding to Chemical Formula 2a, and a grain refinement aid corresponding to Chemical Formula 3b using the above Manufacturing Example 7.

[0249] The silicon wafer having the lower bump metal structure of the above Manufacturing Example 1 formed was immersed in the tin plating solution prepared in the above Manufacturing Example 7, and tin-silver plating was performed by applying a current density of 5ASD.

[0250] Figure 6 is a scanning electron microscope image of the tin-silver plating film result using the plating solution of Manufacturing Example 7 of the present invention.

[0251] The surface SEM image of the resulting tin-silver solder bump is shown in Fig. 6, and the surface roughness results are shown in Table 1 below.

[0252] Experimental Example Chemical Formula 1 (g / l) Chemical Formula 2a (g / l) Chemical Formula 3 (g / l) Roughness (nm) a b a b 1 5 1.81 5 1.28 1.82 0 5 3 5 1.82 7 9 4 8 1.82 8 2 5 5 1.83 57 56 8 1.83 58 1

[0253] These are the results of surface roughness of tin-silver plating films according to the addition of a complexing agent, a grain refiner, and a grain refinement aid in Experimental Examples 1 to 6 of the present invention.

[0254] Therefore, from the experimental examples described above, it can be seen that a tin-silver plating film of excellent quality can be obtained by using a silver complexing agent and a grain refiner having a structure of chemical formula 1, and a more uniform tin-silver plating film can be formed by using a grain refiner having a structure of chemical formula 3.

[0255]

[0256] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0257] The scope of the present invention is indicated by the claims described below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. Tin ion source; silver ion (Ag + ) source; and organic additives; The above organic additive is a silver (Ag) complexing agent represented by the following <Chemical Formula 1>, a tin carrier, A tin-silver plating solution characterized by comprising a grain refiner represented by the following <Chemical Formula 2> and a grain refiner aid represented by the following <Chemical Formula 3>: <Chemical Formula 1> In the above chemical formula 1, R1 and R2 are each independently hydrogen, allyl having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, or a primary alcohol functional group having 1 to 6 carbon atoms containing a hydroxyl group, <Chemical Formula 2> In the above chemical formula 2, R4 is hydrogen; a linear alkyl having 1 to 7 carbon atoms; a branched alkyl having 5 to 20 carbon atoms; or a functional group containing an aromatic ring, R5 is hydrogen; linear alkyl having 1 to 15 carbon atoms; branched alkyl having 5 to 20 carbon atoms; or linear alkyl having 2 to 7 carbon atoms including a hydroxyl group, R6 is hydrogen; linear alkyl having 1 to 12 carbon atoms; or branched alkyl having 5 to 20 carbon atoms, R7 is hydrogen; linear alkyl having 1 to 15 carbon atoms, or branched alkyl having 5 to 20 carbon atoms; X is at least one selected from the group of ions consisting of chlorine (Cl), bromine (Br), iodine (I), nitrate (NO3), sulfate (SO4), carbonate (CO3), and hydroxyl (OH), <Chemical Formula 3> In the above chemical formula 3, R8 is alkyl having 2 to 10 carbon atoms, R9 is a hydrocarbon linking group having 2 to 10 carbon atoms, R 10 is a hydrocarbon linking group containing an aromatic ring, R 11 It is a polymer having 3 to 70 repeating groups composed of at least one of ethylene, propylene, and butylene, and includes hydrogen, sulfonate, or phosphonate as a terminal group.

2. In paragraph 1, The above tin carrier is a tin-silver plating solution characterized by being represented by the following <chemical formula 4>: <Chemical Formula 4> In the above chemical formula 4, A is substituted or unsubstituted C6 to C 30 An aryl group or a heteroaryl having 6 to 30 ring atoms, wherein each of one or more ring carbon atoms includes a heteroatom composed of at least one of nitrogen, oxygen and sulfur, R3 is hydrogen, substituted or unsubstituted C1 to C 30 Alkyl group, substituted or unsubstituted C3 to C 30 Cycloalkyl group, substituted or unsubstituted C2 to C 30 Alkenyl group, substituted or unsubstituted C2 to C 30 Alkynyl group, substituted or unsubstituted C1 to C 30 It is any one of an alkoxy group, a hydroxy group, a sulfonate group ionic bonded with an alkali metal cation, a phosphonate group ionic bonded with an alkali metal cation, a nitronate group ionic bonded with an alkali metal cation, and a chlorate group ionic bonded with an alkali metal cation. n1 to n4 are each independently integers from 0 to 26, and the sum of n1 to n4 is from 10 to 26.

3. In paragraph 1, R of the above <chemical formula 3> 10 A tin-silver plating solution characterized in that the tin-silver plating solution is any one selected from the group consisting of Benzene, Biphenyl, Furan, Imidazole, Indazole, Indole, Indolizine, Isoindole, Isooxazole, Isoquinoline, Naphthalene, Oxazole, Phenalene, Pyran, Pyrazine, Pyrazole, Pyridazine, Pyridine, Pyrimidine, Pyrrole, Pyrrolizine, Quinazoline, Quinoline, and Thiophene.

4. In paragraph 1, A tin-silver plating solution characterized in that tin ions and silver ions in the above tin-silver plating solution are provided in a weight ratio of 75:25 to 99.9:0.

1.

5. In paragraph 1, A tin-silver plating solution characterized in that the tin ion source comprises at least one water-soluble tin compound selected from the group consisting of tin sulfate, tin hydrochloride, tin sulfamate, tin acetate, tin phosphate, tin methanesulfonate, tin gluconate, and tin carbonate.

6. In paragraph 1, The above silver ion (Ag + ) A tin-silver plating solution characterized in that the supply source includes at least one water-soluble silver (Ag) compound selected from the group consisting of silver sulfuric acid, silver hydrochloric acid, silver sulfamic acid, silver acetic acid, silver phosphate, silver methanesulfonic acid, silver gluconic acid, and silver carboxylic acid.

7. In paragraph 1, The above silver ion (Ag + ) A tin-silver plating solution characterized in that the silver (Ag) complexing agent is provided in a molar ratio of 1:1 to 1:10 relative to the supply source.

8. In paragraph 1, A tin-silver plating solution characterized in that it further comprises at least one of an electrolyte, an antioxidant, and a leveling agent.

9. In paragraph 8, A tin-silver plating solution characterized in that the electrolyte is either a hydroxycarboxylic acid or an alkanesulfonic acid.

10. In paragraph 8, A tin-silver plating solution, characterized in that the antioxidant is at least one selected from the group consisting of catechol, hydroquinone, resorcinol, cresol, phloroglucinol, oxyhydroquinone, and pyrogallol.

11. In paragraph 8, A tin-silver plating solution, characterized in that the smoothing agent is at least one selected from the group consisting of a nonionic interface activator, a cationic interface activator, an anionic interface activator, and a synthetic polymer.

12. Tin ion source; silver ion (Ag + ) source; and organic additives; A step of exposing a lower bump metal structure to a plating bath containing a tin-silver plating solution, characterized in that the organic additive includes a silver (Ag) complexing agent represented by the following <Chemical Formula 1>, a tin carrier, a grain refiner represented by the following <Chemical Formula 2>, and a grain refinement aid represented by the following <Chemical Formula 3>; and A method for forming a tin-silver solder bump, comprising: a step of plating a tin-silver alloy on the lower bump metal structure by applying current; <Chemical Formula 1> In the above chemical formula 1, R1 and R2 are each independently hydrogen, allyl having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, or a primary alcohol functional group having 1 to 6 carbon atoms containing a hydroxyl group, <Chemical Formula 2> In the above chemical formula 2, R4 is hydrogen; a linear alkyl having 1 to 7 carbon atoms; a branched alkyl having 5 to 20 carbon atoms; or a functional group containing an aromatic ring, R5 is hydrogen; linear alkyl having 1 to 15 carbon atoms; branched alkyl having 5 to 20 carbon atoms; or linear alkyl having 2 to 7 carbon atoms including a hydroxyl group, R6 is hydrogen; linear alkyl having 1 to 12 carbon atoms; or branched alkyl having 5 to 20 carbon atoms, R7 is hydrogen; linear alkyl having 1 to 15 carbon atoms, or branched alkyl having 5 to 20 carbon atoms; X is at least one selected from the group of ions consisting of chlorine (Cl), bromine (Br), iodine (I), nitrate (NO3), sulfate (SO4), carbonate (CO3), and hydroxyl (OH), <Chemical Formula 3> In the above chemical formula 3, R8 is alkyl having 2 to 10 carbon atoms, R9 is a hydrocarbon linking group having 2 to 10 carbon atoms, R 10 is a hydrocarbon linking group containing an aromatic ring, R 11 It is a polymer having 3 to 70 repeating groups composed of at least one of ethylene, propylene, and butylene, and includes hydrogen, sulfonate, or phosphonate as a terminal group.

13. In paragraph 12, A method for forming a tin-silver solder bump, characterized in that, in the step of plating the tin-silver alloy, the applied current has a current density of 1 ASD to 10 ASD.

14. A tin-silver solder bump formed by the method of Article 12.

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