Tin plating solution for solder bump

Abstract

One embodiment of the present invention provides a tin electroplating solution and a method for forming tin solder bumps using same. The tin electroplating solution according to an embodiment of the present invention includes a novel nucleation accelerator and a particle growth inhibitor, enabling the formation of uniform tin solder bumps with few voids, and thus has excellent performance.

Description

Tin plating solution for solder bumps

[0001] The present invention relates to a tin plating solution, and more particularly, to a tin plating solution for solder bumps.

[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 tin-based plating solution on copper (or copper / nickel) pillars on a copper-based under bump metallurgy (UBM), and there is a need to develop a plating solution for solder bumps to form uniform bumps with few voids.

[0005] (Patent Document 1) Republic of Korea Patent Publication No. 10-2233334

[0006] (Patent Document 2) Republic of Korea Patent Publication No. 10-0934401

[0007] (Patent Document 3) Republic of Korea Patent Publication No. 10-1738535

[0008] The present invention aims to provide a tin plating solution for solder bumps capable of forming an excellent plating film structure on solder bumps by solving the problems of the above-described prior art.

[0009] 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.

[0010] In order to achieve the above technical task, one embodiment of the present invention provides a tin electroplating solution.

[0011] According to one embodiment of the present invention, a tin electroplating solution is a tin electroplating solution for solder bumps, comprising tin ions; an electrolyte; a nucleation accelerator; and a grain growth inhibitor; wherein the nucleation accelerator is represented by the following <Chemical Formula 1>, and the grain growth inhibitor is represented by the following <Chemical Formula 2>.

[0012] <Chemical Formula 1>

[0013]

[0014] In the above chemical formula 1,

[0015] R1 is alkyl having 2 to 10 carbon atoms,

[0016] R2 is a hydrocarbon linking group having 2 to 10 carbon atoms,

[0017] R3 is a hydrocarbon linking group having 6 to 60 carbon atoms and containing an aromatic ring,

[0018] R4 is a polymer of 3 to 60 repeating groups composed of at least one of ethylene, propylene and butylene, and the terminal group is composed of hydrogen, sulfonate or phosphonate,

[0019] <Chemical Formula 2>

[0020]

[0021] In the above chemical formula 2,

[0022] A is a nonmetal element with an electronegativity of 2.0 to 3.5,

[0023] R5 to R7 are each independently a linear or branched alkyl group having 3 to 13 carbon atoms, and are substituted or unsubstituted with an amine substituent.

[0024] In an embodiment of the present invention, the tin electroplating solution may be characterized in that R3 in the above <Chemical Formula 1> is a linking group 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.

[0025] In an embodiment of the present invention, in the above <chemical formula 2>, A may be a tin electroplating solution characterized in that it is one selected from the group consisting of Ga, Si-H, B, P, CH, and N.

[0026] In an embodiment of the present invention, the nucleation accelerator may be a tin electroplating solution characterized in that it is included in the tin electroplating solution at a concentration of 1 g / L to 60 g / L.

[0027] In an embodiment of the present invention, the nucleation accelerator may be a tin electroplating solution characterized by having a molecular weight of 100 g / mol to 1000 g / mol.

[0028] In an embodiment of the present invention, the particle growth inhibitor may be a tin electroplating solution characterized in that it is included in the tin electroplating solution at a concentration of 0.01 g / L to 5 g / L.

[0029] In an embodiment of the present invention, the particle growth inhibitor may be a tin electroplating solution characterized by having a molecular weight of 180 g / mol to 660 g / mol.

[0030] In an embodiment of the present invention, it may be a tin electroplating solution characterized by further including a bubble generation inhibitor.

[0031] In an embodiment of the present invention, the foaming inhibitor may be a tin electroplating solution characterized in that it is at least one selected from the group consisting of ethyl alcohol, isopropyl alcohol, and silane compounds.

[0032] In an embodiment of the present invention, the bubble generation inhibitor may be a tin electroplating solution characterized in that the tin electroplating solution is included in a concentration of 0.001 g / L to 5 g / L.

[0033] In an embodiment of the present invention, the tin electroplating solution may be characterized in that the tin ions are included in the tin electroplating solution at a concentration of 30 g / L to 80 g / L.

[0034] In an embodiment of the present invention, the electrolyte may be a tin electroplating solution characterized by being methanesulfonic acid (MSA).

[0035] In an embodiment of the present invention, the electrolyte may be a tin electroplating solution characterized in that it is included in the tin electroplating solution at a concentration of 20 g / L to 140 g / L.

[0036] In an embodiment of the present invention, it may be a tin electroplating solution characterized by further including an antioxidant.

[0037] In an embodiment of the present invention, the antioxidant may be a tin electroplating solution characterized in that it is Catechol.

[0038] In an embodiment of the present invention, the tin electroplating solution may be characterized in that the antioxidant is included in the tin electroplating solution at a concentration of 1 g / L to 10 g / L.

[0039] In order to achieve the above technical task, another embodiment of the present invention provides a method for forming a tin solder bump.

[0040] A method for forming a tin solder bump according to an embodiment of the present invention comprises the steps of: exposing a lower bump metal structure to a plating bath containing a tin electroplating solution, wherein the plating bath comprises tin ions; an electrolyte; a nucleation promoter; and a grain growth inhibitor; wherein the nucleation promoter is represented by the following <Chemical Formula 1> and the grain growth inhibitor is represented by the following <Chemical Formula 2>; and applying a current to plate tin on the lower bump metal structure.

[0041] <Chemical Formula 1>

[0042]

[0043] In the above chemical formula 1,

[0044] R1 is alkyl having 2 to 10 carbon atoms,

[0045] R2 is a hydrocarbon linking group having 2 to 10 carbon atoms,

[0046] R3 is a hydrocarbon linking group having 6 to 60 carbon atoms and containing an aromatic ring,

[0047] R4 is a polymer of 3 to 60 repeating groups composed of at least one of ethylene, propylene and butylene, and the terminal group is composed of hydrogen, sulfonate or phosphonate,

[0048] <Chemical Formula 2>

[0049]

[0050] In the above chemical formula 2,

[0051] A is a nonmetal element with an electronegativity of 2.0 to 3.5,

[0052] R5 to R7 are each independently a linear or branched alkyl group having 3 to 13 carbon atoms, and are substituted or unsubstituted with an amine substituent.

[0053] In an embodiment of the present invention, a method for forming a tin solder bump may be provided, characterized in that in the step of plating the tin, the applied current has a current density of 1 ASD to 20 ASD.

[0054] Another embodiment of the present invention for achieving the above technical task provides a tin solder bump formed by the method for forming the tin solder bump.

[0055] According to embodiments of the present invention, it is possible to realize excellent plating film characteristics of solder bumps. Specifically, it is possible to form 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).

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] Figure 7 is a scanning electron microscope image of the tin-silver plating film result using the plating solution of Manufacturing Example 8 of the present invention.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0068]

[0069] A tin electroplating solution according to one embodiment of the present invention is described.

[0070] A tin electroplating solution according to one embodiment of the present invention is a plating solution used to form tin solder bumps in a flip chip manufacturing process, and includes tin ions, an electrolyte, a nucleation accelerator, and a grain growth inhibitor. The tin electroplating solution according to one embodiment of the present invention may not include any metal ions other than tin ions.

[0071] Tin ions exist in an ionized state in the electrolyte, for example, Sn, which is divalent. 2+ or 4-membered Sn4+ It can exist in the plating solution in the form of .

[0072] At this time, the concentration of the tin ion may be, for example, 30 g / L to 80 g / L.

[0073] The electrolyte serves as a solvent for the tin electroplating solution and serves as a path for tin ions to move during tin plating. The electrolyte may contain a current-conducting substance, an acidic substance, or, for example, an aliphatic sulfonic acid.

[0074] At this time, the electrolyte may be, but is not limited to, methanesulfonic acid (MSA). At this time, the concentration of the electrolyte may be, for example, included at a concentration of 20 g / L to 140 g / L.

[0075] The tin electroplating solution may further include additives for smooth formation of solder bumps, and the tin electroplating solution according to one embodiment of the present invention includes a nucleation accelerator and a grain growth inhibitor.

[0076] First, the nucleation accelerator plays a role in promoting nucleation within the solder bump and corresponds to a compound represented by the following <Chemical Formula 1>.

[0077] <Chemical Formula 1>

[0078]

[0079] In the above chemical formula 1,

[0080] R1 is alkyl having 2 to 10 carbon atoms,

[0081] R2 is a hydrocarbon linking group having 2 to 10 carbon atoms,

[0082] R3 is a hydrocarbon linking group having 6 to 60 carbon atoms and containing an aromatic ring, and may be any one linking group selected from the group consisting of, for example, 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.

[0083] R4 is a polymer having 3 to 60 repeating groups composed of at least one of ethylene, propylene and butylene, and the terminal group is composed of hydrogen, sulfonate or phosphonate.

[0084] At this time, the concentration of the nucleation accelerator represented by the above <chemical formula 1> may be included in a range of 1 g / L to 60 g / L, but is not limited thereto.

[0085] In addition, the molecular weight of the nucleation accelerator represented by the above <Chemical Formula 1> may preferably be 100 g / mol to 1000 g / mol.

[0086]

[0087] Next, the particle growth inhibitor plays a role in inhibiting the growth of particles generated within the solder bump and preventing the particle size from increasing, and is represented by the following <Chemical Formula 2>.

[0088] <Chemical Formula 2>

[0089]

[0090] In the above chemical formula 2,

[0091] A is a nonmetal element with an electronegativity of 2.0 to 3.5,

[0092] R5 to R7 are each independently a linear or branched alkyl group having 3 to 13 carbon atoms, and are substituted or unsubstituted with an amine substituent.

[0093] At this time, the concentration of the particle growth inhibitor represented by the above <Chemical Formula 2> may be included as 0.01 g / L to 5 g / L, but is not limited thereto.

[0094] In addition, the molecular weight of the particle growth inhibitor represented by the above <Chemical Formula 2> may preferably be 180 g / mol to 660 g / mol.

[0095]

[0096] Additionally, in an embodiment of the present invention, an antioxidant and a foaming inhibitor may be further included as additives to the tin electroplating solution.

[0097] Antioxidants prevent the tin film formed by electroplating from oxidizing. The tin film grown using a tin plating solution can be oxidized simultaneously with the plating process by the electrolyte. Adding additional antioxidants can protect the tin film from oxidation.

[0098] The antioxidant may be an antioxidant known in the art, and may be at least one selected from the group consisting of catechol, hydroquinone, resorcinol, cresol, phloroglucinol, oxyhydroquinone, and pyrogallol. Preferably, catechol may be used. At this time, the concentration of the antioxidant may be included at a concentration of 1 g / L to 10 g / L.

[0099] The foaming inhibitor may be, for example, at least one selected from the group consisting of silane compounds, ethyl alcohol, and isopropyl alcohol. In this case, the foaming inhibitor may be present at a concentration of 0.1 g / L to 5 g / L.

[0100]

[0101] Another embodiment of the present invention provides a method for forming a tin solder bump.

[0102] The method for forming a solder bump generally corresponds to a method of forming a copper-based metal pillar and then plating a tin solder bump on it, and a continuous plating process can be used.

[0103] A method for forming a tin solder bump according to an embodiment of the present invention comprises the steps of: exposing a lower bump metal structure to a plating bath containing a tin electroplating solution, wherein the plating bath comprises tin ions; an electrolyte; a nucleation promoter; and a grain growth inhibitor; wherein the nucleation promoter is represented by the following <Chemical Formula 1> and the grain growth inhibitor is represented by the following <Chemical Formula 2>; and applying a current to plate tin on the lower bump metal structure.

[0104]

[0105] <Chemical Formula 1>

[0106]

[0107] In the above chemical formula 1,

[0108] R1 is alkyl having 2 to 10 carbon atoms,

[0109] R2 is a hydrocarbon linking group having 2 to 10 carbon atoms,

[0110] R3 is a hydrocarbon linking group having 6 to 60 carbon atoms and containing an aromatic ring, and may be any one linking group selected from the group consisting of, for example, 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.

[0111] R4 is a polymer having 3 to 60 repeating groups composed of at least one of ethylene, propylene and butylene, and the terminal group is composed of hydrogen, sulfonate or phosphonate.

[0112]

[0113] <Chemical Formula 2>

[0114]

[0115] In the above chemical formula 2,

[0116] A is a nonmetal element with an electronegativity of 2.0 to 3.5,

[0117] R5 to R7 are each independently a linear or branched alkyl group having 3 to 13 carbon atoms, and are substituted or unsubstituted with an amine substituent.

[0118] At this time, the concentration of the particle growth inhibitor represented by the above <Chemical Formula 2> may be included as 0.01 g / L to 5 g / L, but is not limited thereto.

[0119] In addition, the molecular weight of the particle growth inhibitor represented by the above <Chemical Formula 2> may preferably be 180 g / mol to 660 g / mol.

[0120] At this time, in the step of plating the above-mentioned comment, the applied current may have a current density of 1 ASD to 20 ASD.

[0121] Another embodiment of the present invention for achieving the above technical task provides a tin solder bump formed by the method for forming the tin solder bump.

[0122]

[0123] 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 and experimental examples.

[0124]

[0125]

[0126] *Manufacturing Example 1: Copper-plated silicon wafer

[0127] Electroplating was performed on a silicon wafer having a pattern using a copper plating solution with a thickness of 10 μm.

[0128] 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.

[0129]

[0130] Manufacturing Example 2: Manufacturing of Plating Solution 1

[0131] Tin methanesulfonate and methanesulfonic acid were mixed to prepare a plating solution containing 50.0 g / L of tin ions (Sn2+) and 120 g / L of methanesulfonic acid ions. 1 g / L of catechol, which acts as an antioxidant, was added as an organic additive, and 0.1 g / L of isopropyl alcohol, which acts as a foaming inhibitor, was added.

[0132]

[0133] Manufacturing Example 3: Manufacturing of Plating Solution 2

[0134] In addition to the plating solution of the above Manufacturing Example 2, a plating solution was prepared further containing 25 g / l of a nucleation accelerator having the following chemical formula 1A structure.

[0135] Chemical formula 1A: trimethylhexane phenol ethoxylate (10)

[0136]

[0137] Manufacturing Example 4: Manufacturing of Plating Solution 3

[0138] In addition to the plating solution of the above Manufacturing Example 2, a plating solution was prepared further containing 17 g / l of a nucleation accelerator having the following chemical formula 1B structure.

[0139] Formula 1B: Disodium trimethylhexane phenol ethoxylate(25) sulfate

[0140]

[0141] Manufacturing Example 5: Manufacturing of Plating Solution 4

[0142] In addition to the plating solution of the above Preparation Example 2, a plating solution was prepared further containing 25 g / l of a nucleation accelerator having the above chemical formula 1A structure and 1 g / l of a particle growth inhibitor having the following chemical formula 2A structure.

[0143] Chemical Formula 2A: Diisobutyl methy butanediamine

[0144]

[0145] Manufacturing Example 6: Manufacturing of Plating Solution 5

[0146] In addition to the plating solution of the above Preparation Example 2, a plating solution was prepared further containing 25 g / l of a nucleation accelerator having the above chemical formula 1A structure and 0.8 g / l of a particle growth inhibitor having the following chemical formula 2B structure.

[0147] Chemical Formula 2B: Triisobutylboron

[0148]

[0149] Manufacturing Example 7: Manufacturing of Plating Solution 6

[0150] In addition to the plating solution of the above Preparation Example 2, a plating solution was prepared further containing 17 g / l of a nucleation accelerator having the above Chemical Formula 1B structure and 1 g / l of a particle growth inhibitor having the above Chemical Formula 2A structure.

[0151]

[0152] Manufacturing Example 8: Manufacturing of Plating Solution 7

[0153] In addition to the plating solution of the above Preparation Example 2, a plating solution was prepared further containing 17 g / l of a nucleation accelerator having the above chemical formula 1B structure and 0.8 g / l of a particle growth inhibitor having the following chemical formula 2B structure.

[0154]

[0155] Experimental Example 1: Performance Evaluation of Tin Plating Solution 1 (Manufacturing Example 2)

[0156] In this Experimental Example 1, a plating performance test of a tin plating solution that does not include a nucleation accelerator and a particle growth inhibitor was conducted using the above Manufacturing Example 2.

[0157] 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 plating was performed by applying a current density of 10ASD.

[0158] 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.

[0159] The surface SEM image of the resulting tin solder bump is shown in Fig. 1, and the surface roughness results are shown in Table 1 below.

[0160]

[0161] Experimental Example 2: Performance Evaluation of Tin Plating Solution 2 (Manufacturing Example 3)

[0162] In this Experimental Example 2, a plating performance test was conducted on a tin plating solution containing only a nucleation accelerator corresponding to Chemical Formula 1A using the above Manufacturing Example 3.

[0163] 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 3, and tin plating was performed by applying a current density of 10ASD.

[0164] 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.

[0165] The surface SEM image of the resulting tin solder bump is shown in Fig. 2, and the surface roughness results are shown in Table 1 below.

[0166]

[0167] Experimental Example 3: Performance Evaluation of Tin Plating Solution 3 (Manufacturing Example 4)

[0168] In this Experimental Example 3, a plating performance test was conducted on a tin plating solution containing only a nucleation accelerator corresponding to Chemical Formula 1B using the above Manufacturing Example 4.

[0169] 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 4, and tin plating was performed by applying a current density of 10ASD.

[0170] 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.

[0171] The surface SEM image of the resulting tin solder bump is shown in Fig. 3 above, and the surface roughness results are shown in Table 1 below.

[0172]

[0173] Experimental Example 4: Performance Evaluation of Tin Plating Solution 4 (Manufacturing Example 5)

[0174] In this Experimental Example 4, a plating performance test was conducted on a tin plating solution further including a nucleation accelerator corresponding to Chemical Formula 1A and a particle growth inhibitor corresponding to Chemical Formula 2A using the above Manufacturing Example 5.

[0175] 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 5, and tin plating was performed by applying a current density of 10ASD.

[0176] 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.

[0177] The surface SEM image of the resulting tin solder bump is shown in Fig. 4, and the surface roughness results are shown in Table 1 below.

[0178]

[0179] Experimental Example 5: Performance Evaluation of Tin Plating Solution 5 (Manufacturing Example 6)

[0180] In this Experimental Example 5, a plating performance test was conducted on a tin plating solution further including a nucleation accelerator corresponding to Chemical Formula 1A and a particle growth inhibitor corresponding to Chemical Formula 2B using the above Manufacturing Example 6.

[0181] 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 plating was performed by applying a current density of 10ASD.

[0182] 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.

[0183] The surface SEM image of the resulting tin solder bump is shown in Fig. 5, and the surface roughness results are shown in Table 1 below.

[0184]

[0185] Experimental Example 6: Performance Evaluation of Tin Plating Solution 6 (Manufacturing Example 7)

[0186] In this Experimental Example 6, a plating performance test was conducted on a tin plating solution further including a nucleation accelerator corresponding to Chemical Formula 1B and a particle growth inhibitor corresponding to Chemical Formula 2A using the above Manufacturing Example 7.

[0187] 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 7, and tin plating was performed by applying a current density of 10ASD.

[0188] 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.

[0189] The surface SEM image of the resulting tin solder bump is shown in Fig. 6, and the surface roughness results are shown in Table 1 below.

[0190]

[0191] Experimental Example 7: Performance Evaluation of Tin Plating Solution 7 (Manufacturing Example 8)

[0192] In this Experimental Example 7, a plating performance test was conducted on a tin plating solution further including a nucleation accelerator corresponding to Chemical Formula 1B and a particle growth inhibitor corresponding to Chemical Formula 2B using the above Manufacturing Example 8.

[0193] 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 8, and tin plating was performed by applying a current density of 10ASD.

[0194] Figure 7 is a scanning electron microscope image of the tin-silver plating film result using the plating solution of Manufacturing Example 8 of the present invention.

[0195] The surface SEM image of the resulting tin solder bump is shown in Fig. 7, and the surface roughness results are shown in Table 1 below.

[0196] Experimental Example Chemical Formula 1 (g / l) Chemical Formula 2 (g / l) Roughness (nm) ABAB1----934225---4853-17--429425-1-222525--0.82426-171-2177-17-0.8197

[0197] These are the results of surface roughness of tin plating films according to the addition of a nucleation accelerator and a particle growth inhibitor in Experimental Examples 1 to 7 of the present invention. Therefore, from the experimental examples described above, the nucleation accelerator having the structure of Chemical Formula 1 can promote nucleation to produce many particles, and the particle growth inhibitor having the structure of Chemical Formula 2 can reduce the particle size by suppressing the growth rate of the produced nuclei. It can be seen that by including such nucleation accelerator and particle growth inhibitor compounds in the tin plating solution, a uniform tin film with minimized particle growth can be formed.

[0198]

[0199] 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.

[0200] 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. As a tin electroplating solution for solder bumps, Containing a tin ion; an electrolyte; a nucleation promoter; and a particle growth inhibitor; The above nucleation accelerator is represented by the following <Chemical Formula 1>, The above particle growth inhibitor is a tin electroplating solution characterized by being represented by the following <Chemical Formula 2>: <Chemical Formula 1> In the above chemical formula 1, R1 is alkyl having 2 to 10 carbon atoms, R2 is a hydrocarbon linking group having 2 to 10 carbon atoms, R3 is a hydrocarbon linking group having 6 to 60 carbon atoms and containing an aromatic ring, R4 is a polymer of 3 to 60 repeating groups composed of at least one of ethylene, propylene and butylene, and the terminal group is composed of hydrogen, sulfonate or phosphonate, <Chemical Formula 2> In the above chemical formula 2, A is a nonmetal element with an electronegativity of 2.0 to 3.5, R5 to R7 are each independently a linear or branched alkyl group having 3 to 13 carbon atoms, and are substituted or unsubstituted with an amine substituent.

2. In paragraph 1, A tin electroplating solution characterized in that in the above <Chemical Formula 1>, R3 is a linking group 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.

3. In paragraph 1, A tin electroplating solution characterized in that in the above <chemical formula 2>, A is any one selected from the group consisting of Ga, Si-H, B, P, CH, and N.

4. In paragraph 1, A tin electroplating solution characterized in that the nucleation accelerator is included in the tin electroplating solution at a concentration of 1 g / L to 60 g / L.

5. In paragraph 1, A tin electroplating solution characterized in that the nucleation accelerator has a molecular weight of 100 g / mol to 1000 g / mol.

6. In paragraph 1, A tin electroplating solution characterized in that the particle growth inhibitor is included in the tin electroplating solution at a concentration of 0.01 g / L to 5 g / L.

7. In paragraph 1, A tin electroplating solution, characterized in that the particle growth inhibitor has a molecular weight of 180 g / mol to 660 g / mol.

8. In paragraph 1, A tin electroplating solution characterized by further comprising a foaming inhibitor.

9. In paragraph 8, A tin electroplating solution characterized in that the above-mentioned foaming inhibitor is at least one selected from the group consisting of ethyl alcohol, isopropyl alcohol, and silane compounds.

10. In paragraph 8, A tin electroplating solution characterized in that the above-mentioned bubble generation inhibitor is included in the tin electroplating solution at a concentration of 0.001 g / L to 5 g / L.

11. In paragraph 1, A tin electroplating solution characterized in that the tin ions are contained in the tin electroplating solution at a concentration of 30 g / L to 80 g / L.

12. In paragraph 1, A tin electroplating solution characterized in that the electrolyte is methanesulfonic acid (MSA).

13. In paragraph 12, A tin electroplating solution characterized in that the electrolyte is included in the tin electroplating solution at a concentration of 20 g / L to 140 g / L.

14. In paragraph 1, A tin electroplating solution characterized by further containing an antioxidant.

15. In paragraph 14, A tin electroplating solution characterized in that the above antioxidant is Catechol.

16. In paragraph 15, A tin electroplating solution characterized in that the antioxidant is included in the tin electroplating solution at a concentration of 1 g / L to 10 g / L.

17. Containing tin ions; electrolytes; nucleation promoters; and particle growth inhibitors; The above nucleation accelerator is represented by the following <Chemical Formula 1>, The above particle growth inhibitor comprises a step of exposing the lower bump metal structure to a plating bath containing a tin electroplating solution characterized by being represented by the following <Chemical Formula 2>; and A step of plating tin on the lower bump metal structure by applying current; A method for forming a tin solder bump, characterized in that it comprises: <Chemical Formula 1> In the above chemical formula 1, R1 is alkyl having 2 to 10 carbon atoms, R2 is a hydrocarbon linking group having 2 to 10 carbon atoms, R3 is a hydrocarbon linking group having 6 to 60 carbon atoms and containing an aromatic ring, R4 is a polymer of 3 to 60 repeating groups composed of at least one of ethylene, propylene and butylene, and the terminal group is composed of hydrogen, sulfonate or phosphonate, <Chemical Formula 2> In the above chemical formula 2, A is a nonmetal element with an electronegativity of 2.0 to 3.5, R5 to R7 are each independently a linear or branched alkyl group having 3 to 13 carbon atoms, and are substituted or unsubstituted with an amine substituent.

18. In paragraph 17, A method for forming a tin solder bump, characterized in that in the step of plating the tin, the applied current has a current density of 1ASD to 20ASD.

19. A tin solder bump formed by the method of Article 18.

Images