TIN ALLOY PLATING SOLUTION
20210140060 · 2021-05-13
Assignee
Inventors
Cpc classification
C25D7/00
CHEMISTRY; METALLURGY
International classification
Abstract
A tin alloy plating solution includes a soluble tin salt, a soluble salt of a metal more noble than tin, and a sulfide compound represented by General Formula (1). In the General Formula (1), (A) is a hydrocarbon group including no oxygen atom and having 1 to 2 carbon atoms, or (A) is a hydrocarbon group including one or more oxygen atoms and having 2 to 6 carbon atoms. The metal which is more noble than tin is preferably silver, copper, gold or bismuth.
Claims
1. (canceled)
2. (canceled)
3. A tin alloy plating solution comprising: a soluble tin salt; a soluble salt of a metal which is more noble than tin; and a sulfide compound represented by General Formula (3), here, in the General Formula (3), n is 1 to 5. ##STR00031##
4. The tin alloy plating solution according to claim 3, wherein the metal which is more noble than tin is at least one or more metals selected from silver, copper, gold, and bismuth.
5. The tin alloy plating solution according to claim 3, further comprising at least one or more types of auxiliary complexing agent selected from a gluconic acid or a salt thereof, a citric acid or a salt thereof, a pyrophosphoric acid or a salt thereof, an ethylenediamine, a thiourea, a mercaptothiazole, a mercaptotriazole, a mercaptotetrazole, and a hydroxyalkylphosphine.
6. The tin alloy plating solution according to claim 3, further comprising at least one or more types of surfactant selected from an anionic surfactant, a cationic surfactant, a non-ionic surfactant, and an amphoteric surfactant.
7. The tin alloy plating solution according to claim 3, further comprising an antioxidant.
8. The tin alloy plating solution according to claim 3, further comprising a complexing agent for tin.
9. The tin alloy plating solution according to claim 3, further comprising a pH adjusting agent.
10. The tin alloy plating solution according to claim 3, further comprising a brightening agent.
11. The tin alloy plating solution according to claim 4, further comprising at least one or more types of auxiliary complexing agent selected from a gluconic acid or a salt thereof, a citric acid or a salt thereof, a pyrophosphoric acid or a salt thereof, an ethylenediamine, a thiourea, a mercaptothiazole, a mercaptotriazole, a mercaptotetrazole, and a hydroxyalkylphosphine.
12. The tin alloy plating solution according to claim 4, further comprising at least one or more types of surfactant selected from an anionic surfactant, a cationic surfactant, a non-ionic surfactant, and an amphoteric surfactant.
13. The tin alloy plating solution according to claim 5, further comprising at least one or more types of surfactant selected from an anionic surfactant, a cationic surfactant, a non-ionic surfactant, and an amphoteric surfactant.
14. The tin alloy plating solution according to claim 4, further comprising an antioxidant.
15. The tin alloy plating solution according to claim 5, further comprising an antioxidant.
16. The tin alloy plating solution according to claim 6, further comprising an antioxidant.
17. The tin alloy plating solution according to claim 4, further comprising a complexing agent for tin.
18. The tin alloy plating solution according to claim 5, further comprising a complexing agent for tin.
19. The tin alloy plating solution according to claim 6, further comprising a complexing agent for tin.
20. The tin alloy plating solution according to claim 7, further comprising a complexing agent for tin.
Description
EXAMPLES
[0074] Next, a detailed description will be given of Examples of the present invention together with Comparative Examples.
<Sulfide Compounds Used in Examples 1 to 13 and Comparative Examples 1 to 3>
[0075] First, the main raw materials and auxiliary raw materials for producing the sulfide compounds described in the first embodiment used in Examples 1 to 13 and Comparative Examples 1 to 3 and the reference numerals of the structural formulas of the produced sulfide compounds are shown in Table 1. In addition, the structural formulas are listed below. The sulfide compounds used in Examples 1 to 13 and Comparative Examples 1 to 3 were produced by the method described in the first embodiment.
TABLE-US-00001 TABLE 1 Sulfide compound Number of Number of Main raw Structural oxygen carbon material Auxiliary raw material Formula atoms atoms Example 1 α-thioglycerol Chloromethane (1-1) 0 1 Example 2 α-thioglycerol Chloroethane (1-2) 0 2 Example 3 α-thioglycerol 2-chloroethanol (1-3) 1 2 Example 4 α-thioglycerol 3-chloro-1-propanol (1-4) 1 3 Example 5 α-thioglycerol 1-chloro-3-methaoxypropane (1-5) 1 4 Example 6 α-thioglycerol 3-chloro-1,2-propanediol (1-6) 2 3 Example 7 α-thioglycerol 2-(2-chloroethoxy)ethanol (1-7) 2 4 Example 8 α-thioglycerol 1-chloro-3-methoxy-2-propanol (1-8) 2 4 Example 9 α-thioglycerol 2-[2-(2-chloroethoxy)ethoxy]ethanol (1-9) 3 6 Example 10 α-thioglycerol Dimethylchloroacetal (1-10) 2 4 Example 11 α-thioglycerol 4-chloro-1,2-dihydroxybenzene (1-11) 2 6 Example 12 α-thioglycerol Chloromethane (1-1) 0 1 Example 13 α-thioglycerol Chloromethane (1-1) 0 1 Comparative — — (1-12) 0 0 Example 1 Comparative α-thioglycerol Isopropylchloride (1-13) 0 3 Example 2 Comparative — — (1-14) — — Example 3 (1-1)
<Sulfide Compounds Used in Examples 14 to 19 and Comparative Examples 4 to 6>
[0076] Next, the main raw materials and auxiliary raw materials for producing the sulfide compound described in the second embodiment used in Examples 14 to 19 and Comparative Examples 4 to 6 and the reference numerals of the structural formulas of the produced sulfide compounds are shown in Table 2. In addition, the structural formulas are listed below. The sulfide compounds used in Examples 14 to 19 and Comparative Examples 4 to 6 were produced by the method described in the second embodiment.
TABLE-US-00002 TABLE 2 Sulfide compound Number of Number of Main raw Structural oxygen carbon material Auxiliary raw material Formula atoms atoms Example 14 α-thioglycerol Dichloromethane (2-1) 0 1 Example 15 α-thioglycerol 1,3-dichloropropane (2-2) 0 3 Example 16 α-thioglycerol 1,4-dichlorobutane (2-3) 0 4 Example 17 α-thioglycerol 1,3-dichloro-2-propanol (2-4) 1 3 Example 18 α-thioglycerol 1,4-dichloro-2-butanol (2-5) 1 4 Example 19 α-thioglycerol 1,4-dichloro-2,3-butanediol (2-6) 2 4 Comparative α-thioglycerol α-thioglycerol (2-7) 0 0 Example 4 Comparative α-thioglycerol 1,5-dichloropentane (2-8) 0 5 Example 5 Comparative — — (2-9) — — Example 6 (2-1)
<Sulfide Compounds Used in Examples 20 to 23>
[0077] Further, the main raw materials and auxiliary raw materials for producing the sulfide compounds described in the third embodiment used in Examples 20 to 23 and the reference numerals of the structural formulas of the produced sulfide compounds are shown in Table 3. In addition, the structural formulas are listed below. The sulfide compounds used in Examples 20 to 23 were produced by the method described in the third embodiment.
TABLE-US-00003 TABLE 3 Sulfide compound Main raw Structural material Auxiliary raw material Formula n Example 20 α-thioglycerol Bis(2-chloroethyl)ether (3-1) 1 Example 21 α-thioglycerol 1,2-bis(2-chloroethoxy) (3-2) 2 ethane Example 22 α-thioglycerol Diethyleneglycolbis (3-3) 3 (2-chloroethyl)ether Example 23 α-thioglycerol Bis[2-[2-(2-chloroethoxy) (3-4) 5 ethoxy]ethyl]ether (3-1)
(Vat of SnAg Plating Solution)
Example 1
[0078] Methane sulfonic acid as a free acid, a sulfide compound of Structural Formula (1-1), a non-ionic surfactant (in which polyoxyethylene and polyoxypropylene were added to ethylenediamine at a ratio of 50:50), and pyrogallol as an antioxidant were mixed and dissolved in an aqueous solution of tin methane sulfonic acid, and then an aqueous solution of silver methane sulfonic acid was added thereto and mixed therewith. Finally, by adding ion-exchanged water thereto, a SnAg plating solution having the following composition was vatted. The molar ratio of the sulfide compound with respect to the Ag amount in the SnAg plating solution having the following composition was 1. The aqueous solution of tin methane sulfonic acid was prepared by electrolyzing a metal tin plate, and the aqueous solution of silver methane sulfonic acid was prepared by electrolyzing a metal silver plate, both in an aqueous solution of methane sulfonic acid.
(Composition of SnAg Plating solution)
[0079] Tin methane sulfonic acid (as Sn.sup.2+): 50 g/L
[0080] Silver methane sulfonic acid (as Ag.sup.+): 0.5 g/L
[0081] Methane sulfonic acid (as free acid): 150 g/L
[0082] Amount (molar ratio) of sulfide compound (Structural Formula (1-1)): 1
[0083] Non-ionic surfactant: 5 g/L
[0084] Antioxidant: 1 g/L
[0085] Ion-exchanged water: remainder
Examples 2 to 11
[0086] In Examples 2 to 11, the sulfide compounds of Structural Formulas (1-2) to (1-11) were used, respectively. In Examples 2 to 11, each SnAg plating solution was vatted in the same manner as in Example 1 except that the sulfide compounds were each changed.
Example 12
[0087] In Example 12, the same sulfide compound of Structural Formula (1-1) was used as in Example 1. In Example 12, the molar ratio of the sulfide compound with respect to the Ag amount in the SnAg plating solution was 100. A SnAg plating solution was vatted in the same manner as in Example 1 except that this molar ratio was changed.
Example 13
[0088] In Example 13, the same sulfide compound of Structural Formula (1-1) was used as in Example 1. In Example 13, copper methane sulfonic acid was used instead of silver methane sulfonic acid to prepare an SnCu alloy plating solution. In addition, a plating solution was vatted in the same manner as in Example 1 except that the alloy type was changed.
Comparative Example 1
[0089] In Comparative Example 1, for comparison with Example 1, the sulfide compound (α-thioglycerol) of Structural Formula (1-12) in which both the number of oxygen atoms and the number of carbon atoms in (A) in General Formula (1) were zero was used. Other than this, the SnAg plating solution was vatted in the same manner as in Example 1.
Comparative Example 2
[0090] In Comparative Example 2, for comparison with Example 2, a sulfide compound of Structural Formula (1-13) in which the number of oxygen atoms was zero and the number of carbon atoms was 3 in (A) in General Formula (1) was used. In this Structural Formula (1-13), the number of oxygen atoms was zero and the number of carbon atoms was 3. Other than this, the SnAg plating solution was vatted in the same manner as in Example 1.
Comparative Example 3
[0091] In Comparative Example 3, for comparison with Example 2, a sulfide compound (2-(ethylthio)ethanol) of Structural Formula (1-14) different from General Formula (1) was used. Other than this, the SnAg plating solution was vatted in the same manner as in Example 1.
Examples 14 to 19
[0092] In Examples 14 to 19, sulfide compounds of Structural Formulas (2-1) to (2-6) were used, respectively. In Examples 14 to 19, each SnAg plating solution was vatted in the same manner as in Example 1 except that the sulfide compound was changed.
Comparative Example 4
[0093] In Comparative Example 4, for comparison with Example 14, a sulfide compound of Structural Formula (2-7) in which both the number of oxygen atoms and the number of carbon atoms in (B) in General Formula (2) were zero was used. Other than this, the SnAg plating solution was vatted in the same manner as in Example 1.
Comparative Example 5
[0094] In Comparative Example 5, for comparison with Example 16, a sulfide compound of Structural Formula (2-8) in which the number of oxygen atoms was zero and the number of carbon atoms was 5 in (B) in General Formula (2) was used. Other than this, the SnAg plating solution was vatted in the same manner as in Example 1.
Comparative Example 6
[0095] In Comparative Example 6, for comparison with Example 15, a sulfide compound (3,7-dithia-1,9-nonanediol) of Structural Formula (2-9) different from General Formula (2) was used. Other than this, the SnAg plating solution was vatted in the same manner as in Example 1.
Examples 20 to 23
[0096] In Examples 20 to 23, the sulfide compounds of Structural Formulas (3-1) to (3-4) were used, respectively. In Examples 20 to 23, a SnAg plating solution was vatted in the same manner as in Example 1 except that the sulfide compound was changed.
[0097] The amounts (molar ratios) of each sulfide compound with respect to the Ag amount in the SnAg plating solution in Examples 1 to 23 and Comparative Examples 1 to 6 are shown in Tables 4 and 5 below.
<Comparison Test and Evaluation>
[0098] For the 29 types of Examples 1 to 23 and Comparative Examples 1 to 6, the transparency of the tin alloy plating solutions immediately after being vatted and the stability of the tin alloy plating solutions which were vatted were evaluated. The stability of the tin alloy plating solution was evaluated by performing an aging stability test and an electrolytic stability test. The results are shown in Tables 4 and 5.
(a) Transparency
[0099] Immediately after being vatted, the 29 types of tin alloy plating solution were put in a transparent glass beaker and the transparency was visually observed. A beaker in which the plating solution was transparent was determined to be “transparent”, and a beaker in which the plating solution became cloudy was determined to be “cloudy”.
(b) Aging Stability Test
[0100] The 29 types of tin alloy plating solutions which were vatted were placed in glass sealed bottles separately and stored in a clean oven made by Panasonic at 50° C. for 6 months. Using an ICP atomic emission spectrometer (ICP-AES, model number ICPE-9800) manufactured by Shimadzu Corporation, the Ag concentration (in the case of an SnAg plating solution) or the Cu concentration (in the case of an SnCu plating solution) in the tin alloy plating solution immediately after being vatted was set as 100% and the residual proportion (%) of the Ag concentration (in the case of the SnAg plating solution) or the Cu concentration (in the case of the SnCu plating solution) remaining in the tin alloy plating solution after storage for 6 months was evaluated as the “residual proportion after aging”. 80% or more was determined to be good.
(c) Electrolytic Stability Test
[0101] The 29 types of tin alloy plating solution which were vatted were used as an electrolytic solution, a copper plate and a platinum plate were arranged in the electrolytic solution as a cathode and as an anode respectively, and electroplating was performed separately for the 29 types of tin alloy plating solutions which were vatted at a vat temperature of 25° C. and a cathode current density of 10 ASD. Since metal components in the plating solution were consumed by electrolytic plating, stannous oxide (SnO) and silver oxide (Ag.sub.2O) powders were added, mixed, and dissolved in the plating solution every 5 Ah/L of electrolytic plating such that the electrolytic plating was performed up to 150 Ah/L while replenishing the metal component in the plating solution. The concentration of the sulfide compound remaining in the tin alloy plating solution after electrolytic plating was quantitatively analyzed by the following high-performance liquid chromatography (HPLC) method. The tin alloy plating solution was filtered with a disposable syringe and analyzed using an HPLC device (model: Prominence) manufactured by Shimadzu Corporation, using L-Column ODS kept at 40° C. with a mobile phase of MeOH (methanol). With the concentration of the sulfide compound immediately after being vatted being set as 100%, the residual proportion (%) of the sulfide compound after electrolytic plating was evaluated as the “residual proportion after aging” of the complexing agent. 80% or more was determined to be good.
TABLE-US-00004 TABLE 4 Amount of Residual Residual sulfide proportion proportion compound after after (molar ratio) Transparency aging (%) electrolysis (%) Example 1 1 Transparent 95 94 Example 2 1 Transparent 91 82 Example 3 1 Transparent 97 88 Example 4 1 Transparent 98 94 Example 5 1 Transparent 96 92 Example 6 1 Transparent 98 99 Example 7 1 Transparent 93 90 Example 8 1 Transparent 98 90 Example 9 1 Transparent 96 95 Example 10 1 Transparent 97 89 Example 11 1 Transparent 87 83 Example 12 100 Transparent 96 98 Example 13 1 Transparent 89 92 Comparative 1 Transparent Evaluation Evaluation Example 1 not not possible possible Comparative 1 Cloudy 83 68 Example 2 Comparative 1 Transparent 54 38 Example 3
TABLE-US-00005 TABLE 5 Amount of Residual Residual sulfide proportion proportion compound after after (molar ratio) Transparency aging (%) electrolysis (%) Example 14 1 Transparent 97 83 Example 15 1 Transparent 94 87 Example 16 1 Transparent 90 91 Example 17 1 Transparent 98 87 Example 18 1 Transparent 95 93 Example 19 1 Transparent 99 97 Comparative 1 Cloudy Evaluation Evaluation Example 4 not not possible possible Comparative 1 Transparent 80 72 Example 5 Comparative 1 Transparent 68 56 Example 6 Example 20 1 Transparent 92 89 Example 21 1 Transparent 94 90 Example 22 1 Transparent 94 92 Example 23 1 Transparent 95 94
[0102] As is clear from Table 1 and Table 4, in Comparative Example 1 using a compound in which (A) in General Formula (1) did not meet the conditions of the first aspect of the present invention, the SH group of the terminal group of the compound reacted with Ag immediately after being vatted to generate a precipitate and evaluation after aging and after electrolytic plating was not possible. In Comparative Example 2 using a sulfide compound in which (A) in General Formula (1) did not meet the conditions of the first aspect of the present invention, the number of carbon atoms was 3, thus, the water solubility of the sulfide compound was low and the residual proportion after aging was 83%, but the residual proportion after electrolysis was as low as 68%, which was unsatisfactory. In addition, in Comparative Example 3 in which the sulfide compound (2-(ethylthio)ethanol) of Structural Formula (1-14) different from General Formula (1) was used, the water solubility of the sulfide compound was low, the residual proportion after aging was 54%, and the residual proportion after electrolysis was as low as 38%, which was unsatisfactory.
[0103] On the other hand, in Examples 1 to 13 using the sulfide compound in which (A) in General Formula (1) met the conditions of the first aspect of the present invention, the residual proportion of Ag and Cu in the plating solution after aging was as high as 87% to 98% and the sulfide compound also remained at a high ratio of 82% to 99% after electrolytic plating. From these results, it was confirmed that the sulfide compound in which (A) in General Formula (1) met the conditions of the first aspect of the present invention was useful as a complexing agent for metals which are more noble than tin.
[0104] As is clear from Table 2 and Table 5, in Comparative Example 4 in which (B) in General Formula (2) did not meet the conditions of the second aspect of the present invention, the disulfide group of the sulfide compound reacted with Ag immediately after being vatted to generate a precipitate and evaluation after aging and after electrolytic plating was not possible. In Comparative Example 5 using the sulfide compound in which (B) in General Formula (2) did not meet the conditions of the second aspect of the present invention, since the carbon chain was 5, the water solubility of the sulfide compound was low and the residual proportion after aging was 80%, but the residual proportion after electrolysis was as low as 72%, which was unsatisfactory. In addition, in Comparative Example 6 of Structural Formula (2-9) different from General Formula (2) of the second aspect of the present invention, since the sulfide compound did not have a glyceryl group, the water solubility of the sulfide compound was low, the residual proportion after aging was 68%, and the residual proportion after electrolysis was 56%, which were both low and unsatisfactory.
[0105] On the other hand, in Examples 14 to 19 using the sulfide compound in which (B) in General Formula (2) met the conditions of the second aspect of the present invention, after aging, the residual proportion of Ag in the SnAg plating solution was as high as 90% to 99%, and the sulfide compound also remained at a high ratio of 83% to 97% after electrolytic plating. From these results, it was confirmed that the sulfide compound in which (B) in General Formula (2) met the conditions of the second aspect of the present invention was useful as a complexing agent for metals which are more noble than tin.
[0106] As is clear from Tables 3 and 5, in Examples 20 to 23 using the sulfide compound which met the conditions of the third aspect of the present invention in which n in General Formula (3) was 1 to 5, after aging, the residual proportion of Ag in the SnAg plating solution was as high as 92% to 95% and the sulfide compound also remained at a high ratio of 89% to 94% after electrolytic plating. From these results, it was confirmed that the sulfide compound which met the condition of the third aspect of the present invention, in which n in General Formula (3) is 1 to 5, was useful as a complexing agent for metals which are more noble than tin.
INDUSTRIAL APPLICABILITY
[0107] It is possible to use the plating solution of the present invention to form parts of electronic components such as bump electrodes of semiconductor wafers and printed circuit boards.