TW201006966A - Electrolytic tin plating solution and electrolytic tin plating method - Google Patents

Abstract

A plating solution and a plating method, which does not use a complexing agent and which provides favorable solder wetting properties and an extremely low coupling rate when electrolytic tin plating is performed, and particularly when electrolytic tin plating is performed using a barrel plating method.

Description

201006966, , t, invention description: [Technical field of the invention] The present invention relates to a tin plating solution and an electrolytic tin clock method; more specifically - relating to electrolytic tin for electroplating wafer components such as ceramic capacitors Plating solution and plating method. [Prior Art] The wafer assembly is a tin plating method (such as a barrel plating method, a flow-through plater method, etc.) in accordance with the shape of the wafer and the configuration of the area to be clocked Metals such as copper, silver, gold, gold, or alloys. The purpose of the tin clock is to provide solderability to the electrode portion of the wafer assembly. However, tin plating, especially roller plating, has a problem that the wafer components will adhere to each other (hereinafter also referred to as aggregation, adhesion, and coupling). The bonded wafers become defective products, which reduce the yield of the product. The proportion of the wafer components that are bonded together in the total number of wafer components is referred to as the coupling ratio. In severe cases, the coupling ratio may exceed 9%. Couplings are known to occur in the case where a conventional electric bell bath caller wafer assembly having sulfuric acid or methyl acid is used in the drum. In order to solve this problem, an unexamined Japanese Patent Application No. 2-82492 discloses a method of forming an electrode on a wafer-modified Tauman electronic grade using a stannous sulfonate (as a stannous salt). a staggering agent such as citric acid, gluconic acid, or pyrophosphoric acid, and a tin plating bath of a glossing agent. However, the plating solution of the plating solution and the wash water 3 94692 201006966 becomes difficult because the plating solution disclosed in Japanese Patent Application Laid-Open No. 2003-82492 includes the wrong agent. Therefore, from the viewpoint of environmental protection, a low pH tin plating bath containing no miscible agent is preferred. Further, in the case of tin plating, tin oxide/valley having an excellent solder wetting property is important to provide solderability to the wafer assembly or the like. The inventors of the present invention have previously improved this, and it has been found that a special naphthol compound can be used as an additive for electrolytic tin plating, and a tin film having a uniform appearance can be formed, and the deposited tin film has good solder wettability. It has also been found that a special naphthol compound can be used to improve the solderability. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a plating solution for a wafer assembly and a plating method for the wafer assembly which does not use a miscible agent and which is implemented when electrolytic tin plating is performed, particularly when using a roller plating method. Electrolytic tin plating provides good solder wetting properties and very low coupling ratio. In order to achieve the above object, the inventors of the present invention have found through diligent research that they can be used in a tin bath bath having a strong acidity (pH 1 or lower), especially in a drum tin plating bath containing no wrong agent. A special compound is used to achieve a smooth tin plating film having a surface hardness higher than that of a conventional film, and to minimize adhesion between the plated substrates. In other words, an aspect of the present invention provides an electrolytic tin plating solution for a wafer assembly comprising (A) stannous ion, (B) acid, (C) N,N-dipolyoxyalkylene-N An alkylamine (N, N~dipolyoxyalkylene-N-alkyl amine), an amine oxide or a mixture thereof, and (D) an anti-adherent agent; wherein the pH is 1 or less. Furthermore, an aspect of the present invention provides an electroplating solution for a wafer assembly, which comprises (E) a tin-plating solution, in addition to a component (A)i(D) plating uniformity improver, in addition to electricity 4 94692 201006966. Furthermore, the aspect of the present invention provides an electrolytic tin plating solution for a wafer assembly, which comprises (F) a compound represented by the following general formula (1) in addition to a component (phantom to (£)). Dilute or propionic acid derivatives, and (G) antioxidants.

CHz = C - COOH ' (1)

R In the above formula, R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Furthermore, an aspect of the present invention provides an electrolytic tin plating solution for a wafer assembly, wherein the N,N-dimeroxyalkyl-N-alkylamine is one or more of the following formulas ( 2) The compound indicated. .(CH2CHCHzO), (CHaCH2〇)zH KN t (2)

X CCH2CHCH20)y(CH2CH20)wH In the above formula, R represents an alkyl group having 6 to 28 carbon atoms, and w, X, y and z each represent an integer between 〇 and 30. However, the sum of W, x, y, and z is not ambiguous. Further, an aspect of the present invention provides an electro-de-tin plating solution for a wafer assembly, wherein the amine oxide is one or more compounds represented by the following general formula (3).

CHaCHROH (3) 1 ο

I

CHjCHR*OH 94692 201006966 In the above formula, R represents an alkyl group, a cycloalkyl group or an aryl group, and r represents a hydrogen atom, an alkyl group or a cycloalkyl group. Further, the aspect of the present invention provides a solution for a wafer set of tin-electric clock solutions wherein the (D) anti-adhesive agent is one or more compounds selected from the group consisting of aryl and aromatic. Furthermore, the present invention provides a method of an electric money wafer assembly comprising electrolytic tin plating of a wafer assembly using an electrolytic tin plating solution comprising (A) stannous ions, (B) An acid, (c) an N,N-dimeric oxygen-extension-N-homoamine, an amine oxide or a mixture thereof, and a (D) anti-adherent; wherein the pH is 1 or less. The electric cylinal liquid of the invention is very effective for preventing the adhesion of the substrate, and the electrical key defects can be minimized, so when electrolytic kicking money is performed on a plurality of substrates such as wafer components, especially the roller is used. When the electroplating method is performed on electrolytic tin ore, the yield of the product can be increased. In other words, smoothing the tin plating film reduces the sticking that occurs when the substrates begin to contact each other. This adhesion is similar to matplating, which causes the substrates to be stuck together and cannot be physically peeled off. Furthermore, increasing the hardness of the surface of the crucible can prevent deformation of the tin plating film caused by softening of the surface of the film (such as matte plating) when the substrates start to contact each other, and can also cause the tin plating film to adhere together. The rate is reduced to a minimum. Further, the plating solution of the present invention does not contain a miscible agent, so that the wastewater treatment is easier than the conventional electrophoresis solution for roller plating. [Embodiment] Abbreviation used in the present specification has the following meanings of 6 94692 201006966 unless otherwise noted. g = g; mg = mg; C = degrees Celsius; min = minutes; m = meters; cm = cm; L = liters; mL = milliliters; A = amperes; and dm2 = square inches. All numerical ranges include boundary points and can be combined in any order. The terms "electroplating solution" and "electroplating bath" as used in this specification have the same meaning and are used interchangeably. The electrolytic tin plating solution of the present invention is an electrolytic tin plating solution for a wafer assembly containing (A) stannous ion, (B) acid, (C) N,N-dipolyoxyalkylene-N-alkane a base amine, an amine oxide, or a mixture thereof, and (D) an anti-adherent; wherein the pH is 1 or lower. These components are disclosed in order as follows. (A) Stannous ion The electroplating bath of the present invention contains stannous ions as a main component. The stannous ion is a divalent tin ion. Any compound which provides stannous ions to the plating bath can be used. Generally, a tin salt of an inorganic acid or an organic acid is preferred. Examples of the tin salt of the acid-free acid include a stannous salt of sulfuric acid or hydrochloric acid; examples of the tin salt of the organic acid include a substituted or unsubstituted alkanesulfonic acid or an alkanolsulfonic acid (e.g., methanesulfonic acid, B) A stannous salt of sulfonic acid, propanesulfonic acid, 2-hydroxyethane-1-sulfonic acid, 2-hydroxypropan-1-ene acid, and 1-pyridylpyrazine-2-taretic acid, and the like. The source of the stannous ion of Yujia is stannous sulfate (salt of inorganic acid) and stannous methanesulfonate (salt of organic acid). The compound which can provide such a plasma can be used singly or in a mixture of two or more types. For example, the amount of stannous ions added to the electroplating bath is between lg/L and 150 g/L, preferably between 5 g/L and 50 g/L, and more is 7 94692 201006966. Between 8g/L and 20g/L. (B) Acid ❹ The acid can be any acid which can adjust the pH to 丨 or lower and can conduct conductivity. Examples of inorganic or organic acids include unsubstituted or unrecorded acid-correcting acid, such as nail secret, ethyl wei, propionic acid, 2 _ _ _ _ _ _ _ _ _ _ _ Burning + acid, and 1, base CP - 2_ two. Preferred is methine; examples of inorganic acids include sulfuric acid and hydrochloric acid, and preferably sulfuric acid. These acids which can adjust the pH to 1 or lower and which can provide conductivity to the secret can be used alone or in a mixture of two or more types. The amount of acid in the electroplating bath solution is preferably at least stoichiometrically equal to the amount of divalent tin ions in the electroplating bath. For example, the amount of free acid in the plating bath is between 10 g/L and 5 〇〇g/L, preferably between 30 g/L and 300 g/L, and more preferably between Between 50g/L and 2〇〇g/L. (C) N,N-dimerized oxygen-based amine-N-alkylamine or amine oxide

The electroplating bath of the present invention contains N,N-dipolyoxyalkylene-1-alkylamine, an amine oxide or a mixture thereof as a main component. The inventors of the present invention have evaluated a variety of nonionic surfactants and have found that by using a specific anionic surfactant N,N-dipolyoxyalkyl-N-alkylamine or amine oxide to achieve the desired A uniform electric clock with a thickness of the film. The N,N-dipolyoxyalkylene-N-alkylamine is preferably a polyoxyalkyl propyl polyoxyethylamine represented by the following formula (2). / (ch2chchzo, (ch2ch2o)zh KN V (2)

(_CH2CHCH2〇)y(CH2CH2〇)wH 8 94692 201006966 In the above formula, r represents a straight or branched chain alkyl group of 6 to 26, and W, χ, y and a solid atom: 〇R, surface dry = However, the sum of W, X, yh is not. . Preferably, y and Z i and: a linear alkyl group of between 8 and 18 carbon atoms, and the sum of (4), y and z is between 10 and 20. Things. The amine oxide is a compound or a plurality of compounds ❹ H* R represented by the following formula (4), and I N I R* 0 (4) is from the fabric, a cycloalkyl group or a aryl group at the age of 3 and may have a substituent. Examples thereof include a butyl group, a pentyl group, a hexyl group, a phenyl group, a tolyl group, a dimethylphenyl group, and a group: the group; the amine oxide of the present invention preferably has the formula (3); one or more of Amine oxide.

CHjCHR'OH CHaCHROH (3) In the above formula, R represents an alkyl group, a cycloalkyl group or an aryl group, and R represents an alkyl group or a cycloalkyl group. The Ν'N~-polyoxyalkylene amide or amine oxide can be used as a film modifying agent in the electroporation of the present invention. In other words, 'N, N-dimerooxyalkyl-N-alkylamine or amine oxide is used to smooth the electro-mineral film, which can occur when the substrates begin to contact each other. 94692 201006966 Minimizing the phenomenon, the adhesion is similar to matt plating, which causes the substrates to be stuck together and physically unable to peel off. In the electroplating bath, an appropriate concentration of the N,N-dipolyoxyalkylene-N-alkylamine or amine oxide is between 〇· 〇U/L to l〇〇g/L, preferably. The system is between lg. lg/L to 50g/L, more preferably between Ig/L and 25g/L. (D) Anti-adhesive agent The electroplating bath of the present invention contains an anti-adhesive agent as a main component. The anti-adhesive agent functions to prevent the electro-mineral wafer assembly from being cohesive (adhesive) together in the electric forging bath of the present invention. The anti-adhesive agent is used to prevent the wafer assembly from sticking together, especially for preventing the wafer assembly from sticking together during the barrel plating process. Examples of the anti-adhesive agent include aromatic aldehydes and aromatic ketones. Preferred examples of the anti-adhesive agent include benzaldehyde and benzylideneacetone. The effect of these compounds is in particular to increase the surface hardness of the film. In other words, increasing the surface hardness of the film prevents deformation of the tin plating film caused by softening of the surface of the film (such as matte plating) when the substrates start to contact each other, and can also reduce the incidence of sticking the tin plating film to lowest. The preferred anti-adherent agents described above are especially effective when used in combination with (C) N,N-dipolyoxyalkylalkylamines or amine oxides. In the electric town bath, the appropriate concentration of the anti-adhesive agent is between 1 and 5 〇g/L, preferably between 5 mg/L and 丨0 g/L, and more preferably between 丨. How about a few to five §. (E) Electric ore uniformity improver The electric ore concentrate of the present invention preferably contains an electric ore homogeneity improver as an optional component (_i meter component) in addition to the above components (1) to (9). The electric chain uniformity improver of the present invention is a compound which improves plating uniformity particularly in a low current region of 94692 10 201006966. Especially in the case of roller plating, during the process, the system to be electroplated is placed in the drum, and the plating is performed while partially immersing in the electric plating solution, thereby changing the current density. The current density range of the object to be electroplated will vary widely from high current density region to low current density region, and there will be a problem of low plating uniformity in the low current density region, so the plating film will have a change . By adding the electric clock uniformity improver, electroplating can be performed uniformly even in the low current density region. ❹ Examples of the plating uniformity improver include 2-naphthol-7-sulfonic acid and the compound (I) having the structural formula shown below. The 2-naphthol-7-sulfonic acid may be in the form of a free acid or in the form of a salt. Suitable salts of 2-naphthol-7-sulfonic acid include water-soluble salts such as potassium salts, sodium salts, ammonium salts, and tin salts, and the like, but are preferably potassium salts and sodium salts, and even more preferably 2- Sodium naphthol-7-sulfonate. These salts may be used singly or as a mixture of two or more types. As shown in Patent Document 2, the sulfonic acid group is bonded to the hydroxy group at a specific position on the naphthalene ring. The specific naphthol sulfonic acid, particularly the 2-naphthol-7-sulfonic acid or its alkali salt, is significantly more effective than the other. Naphtholsulfonic acid or a salt thereof. Other positional isomers such as 2-naphthol-6-sulfonic acid and 1-naphthol-4-sulfonic acid have little effect and are therefore not preferred.

The amount of 2-naphthol-7-sulfonic acid or a salt thereof to be added to the electroplating bath is between 0. Olg/L and 20 g/L, preferably between 0. lg/L and 10 g/L. Between 2, 0, and, for example, between 0. 2g/L and 5g/L. On the other hand, if the above compound (I) is used, the appropriate concentration used in the electrophoresis solution i is between 0.1 mg/L and l〇g/L, preferably between 1 mg/L and The better between lg/L is between 5 mg/L and 100 mg/L. These plating uniformity improvers may be used singly or in combination. (F) Acrylic acid or acrylic acid derivative The electric bond bath of the present invention preferably contains one or more acrylic acid or acrylic acid derivatives represented by the following general formula (1) as an optional component. In particular, acrylic acid and mercaptoacrylic acid are preferred. In the formula, R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. The mercaptoacrylic acid or acrylic acid is preferably added to the electroplating bath of the present invention as an auxiliary anti-adhesive agent for supporting the above (D) anti-adhesive agent. The methacrylic acid or acrylic acid can further increase the anti-adhesive effect of the (D) anti-adhesive component, especially having an effect of increasing the surface hardness of the film, and the anti-adhesive effect can be increased by using the (D) anti-adhesive agent in combination. Sustainability. The amount of the acrylic acid or acrylic acid derivative represented by the above formula (1) in the plating bath should be appropriate, so the concentration thereof is between 01 g/L and iOOg/L, preferably between 〇. Between ig/L and 50 g/L, more preferably between 0.5 g/L and 10 g/L. (G) Antioxidant An antioxidant can be optionally used in the plating solution of the present invention. The antioxidant is used to prevent oxidation of divalent tin ions to tetravalent tin ions, and Example 12 94692 201006966 includes hydroquinone, catechol, resorcinol, phloroglucinol, pyrogallol, hydrogen It is made of acid and its salt. 5g/L, more preferably between 0. 5g / L, preferably between 0mg / L and 50g / L, preferably between 0. 5g / L Between 5g/L. Further, if necessary, other conventional additives such as a glossing agent, a smoothing agent, a conductive agent, an anodic solvent, and the like may be added to the plating bath of the present invention. When the electroplating bath is produced, the order of addition of various components is not particularly limited, but from the viewpoint of safety, acid is added after adding water, and after fully mixing, tin salt is added, thoroughly mixed, and then sequentially Add other required chemicals. Examples of wafer components that can be electroplated using the electroplating solution of the present invention include electronic components such as resistors, capacitors, inductors, variable resistors, variable capacitors, and other passive components, quartz oscillators, LC filters, ceramic filters , delay lines, SAW filters, and other functional components, switches, connectors, relay fuses, optical components, ❹, and other contact components. Plating Method The plating method used in combination with the plating solution of the present invention may be a conventional electroplating method such as a barrel plating method, an electroplating method using a flow-through electroplating apparatus, or the like. In the plating solution, the concentration of each component (A) to (F) can be arbitrarily selected in accordance with the above description of each component. The plating method used in combination with the plating solution of the present invention can be carried out at a bath temperature of between 10 ° C and 50 ° C, preferably between 15 ° C and 30 ° C. In addition, the cathode current density is between 0.01 to 5 A/dm 2 , which is better than the 13 94692 201006966 state, or may be appropriately selected within a range between 0.05 to 3 A/dm 2 equal to the plating process, the plating The bath may be stirred in a non-stirred state with a stirrer or the like, or recycled using a pump or the like. [Example 1] A bath was formed using a tin plating solution having the following composition. (A) Stannous succinate (as tin ion): 12g / L (B) methyl acid (as free acid): 50ff / L (6) amine oxide: Ethylene oxide, sulfhydryl _, with epoxy B Burned polymer with 2, 2'~•(oxy-ionic imino) bis[ethanol](2··1) N-[3-(C9-ll-isoalkoxy)propyl] derivative L〇g/L (D) benzylideneacetone: 0. 4g / L (E) methacrylic acid: 2g / L (F) 2-naphthyl-7-sodium sulphate: 0. 5g / L (G) Potassium hydroquinone sulfonate: 2 g/L (H) Distilled water: The balance was subjected to roller tin plating on a nickel-plated wafer resistor 使用 using a 1 L tin plating solution under the conditions shown below, and woven and subjected to various evaluations. The results are not shown in Table 1. Roller plating object for electric money: wafer resistor roller ΐ. Yamamoto minibarrel (volume: 140 mL) Rotating speed: 20 rpm Nickel plating: 2. 4A-60 minutes tin plating: 2A-90 minutes 14 94692 201006966 Wafer 1 ^Resistors (size 1608): 4.71^15111 B/cylinder ball: 1mm 0 30mL/barrel evaluation item • Shovel thickness After roller plating, the front and back surfaces are measured using a fluorescent X-ray film thickness gauge. The plating thickness on the left and right sides, and the thickness and the variation in plating thickness between points are evaluated. Coupling Rate® The roller-plated wafer assembly is divided into a bonded wafer and a non-adherent wafer, and the coupling ratio is calculated. The coupling ratio is the weight of the bonded wafer as the molecule and the weight of all the wafers. The ratio calculated as the denominator (adhesive wafer / (adhesive wafer + unbonded wafer) χ 100) 〇 solder wetting test prepared each of the specific examples and comparative examples of the plating solution 1 liter, at 2 A φ current and 20 Tin plating was carried out for 90 minutes at a bath temperature of °C. Each of the obtained tin plating films was subjected to a humidity resistance test at 105 ° C and 100% RH for 8 hours, and then soldered by using a Multi Solderability Tester SWET-2100 manufactured by TARUTIN. The equilibrium method measures the zero cross 1: ime, ZCT to evaluate the solder wetting properties of the plated film that has been tested for humidity resistance. The measurement conditions are as shown below. Zero crossing time measurement conditions Solder paste: Sn: Ag: Bi: Cu = 96:2.5:1:0.5 15 94692 201006966

Bath temperature: 245 ° C Immersion depth: 0. 25 mm (mm) Immersion speed: 2 mm / sec (mm / sec) Immersion time: 8 seconds to measure the zero crossing time, and the value of 3.0 seconds or less See as passing (PASS). The pass rate is calculated as a percentage calculated by taking the number of samples with a zero crossing time of 3.0 seconds or less as a numerator and using the total number of samples (10 samples) as the denominator. [Examples 2 to 11 and Comparative Examples 1 to 7] Tin plating baths having the ratios shown in Tables 1 and 2 were produced in the same manner as in Example 1, and various tests similar to those in Example 1 were carried out. The results are also shown in Tables 1 and 2. Note that the symbol associated with the plating thickness evaluation is shown below. The plating thickness on the front surface, the back surface, the left side and the right side is uniform: 0 plating unevenness: △

Electroplated without forming: X 16 94692 201006966 ❹ Table 1 Numerical value M g / L. However, the value of the compound (1) is expressed in mg/L)

Note 1) The N,N-polyoxyalkylene group is represented by the following structural formula (2), in which w+x+y+z=16. ❹

KN

(ϋΗ2ϋΗ0Η2Ο)4(0Η2€Η2Ο)ζΗCCH2CHCH20)y(CH2CH20)wH (2) 94692 17 201006966

In the formula, X1 to X111 are about 13 ′ Y1 to Y111 are about u, and the molecular weight is about 800. Knife CH,

P^CHC^CHjC^C^H M-OHg-CHfN

Note 2) Surfactant 2 is:

HZN

NH2 94692 18 201006966 R: polyoxyalkylene, note 3) surfactant 3: polyoxyethylidene phenyl ether note 4) surfactant 4: lauryl dimethyl betaine [simple figure Explanation] No [Main component symbol description] None ❹ 19 94692

Claims (1)

201006966 VII. Patent application scope: 1. An electrolytic tin plating solution for wafer components, comprising: (A) stannous ion, (B) acid, (C) N, N-dimer oxygen alkyl-N An alkylamine, an amine oxide or a mixture thereof, and (D) an anti-adherent; wherein the pH is 1 or lower. 2. The electrolytic tin plating solution for a wafer module according to the first aspect of the patent application, further comprising: (E) a plating uniformity improver. 3. The electrolytic tin plating solution for a wafer module according to claim 1, further comprising: (F) one or more acrylic acid or acrylic acid derivatives represented by the following general formula (1); and (G) Antioxidants CH2 = C - COOH I R Wherein R represents hydrazine or an alkyl group having from 1 to 3 carbon atoms. 4. The electrolytic tin plating solution for a wafer assembly according to claim 1, wherein the N,N-dimeroxyalkyl-N-alkylamine is one or more of the following formula (2) The compound represented by CH(CHCHCHgO^iCH^HjOizH KN ((2) X CCH2CHCH20) y(CH2CH20)wH wherein R represents an alkyl group having between 6 and 28 carbon atoms, and w, x, y and The z series each represent an integer between 0 and 30; the sum of w, x, y, and z is not 0. 5. The electrolytic tin plating solution for a wafer assembly according to claim 1, wherein The amine oxide is one or more compounds represented by the following formula (3): 94692 201006966 CHaCHROH, R〇W^O (3) CHiCHROH wherein R represents an alkyl group, a cycloalkyl group or an aryl group, and R' represents hydrogen. An electrolytic tin plating solution for a wafer module according to the first aspect of the invention, wherein the (D) anti-adhesive agent is selected from the group consisting of an aromatic aldehyde and an aromatic ketone. One or more compounds of the group. 7. 7. A method of electroplating a wafer assembly comprising using an electrolytic tin plating solution to a wafer set Electrolytic tin plating, the electrolytic tin plating solution comprising (A) stannous ion, (B) acid, (C) N,N-dipolyoxyalkylene-N-alkylamine, amine oxide or Mixture, and (D) anti-adhesive agent; wherein, the pH is 1 or lower. ❹ 21 94692 201006966 IV. Designated representative figure: There is no drawing in this case (1) The representative drawing of the case is: () The symbol of the symbol of this representative figure is briefly explained: 5. If there is a chemical formula in this case, please disclose the chemical formula that best shows the characteristics of the invention: This case does not represent the chemical formula 2 94692