JP2000265294A - Tin and tin alloy plating bath, plating film and lead frame for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plating film provided with excellent soldering performance of being hard to be deteriorated due to a heat history in particular by incorporating it with a soluble tin salt and a quaternary compd. SOLUTION: As to a thinning film formed by using a plating bath contg. a soluble tin salt and a quaternary compd., the quaternary compd. is oxidized due to a heat history, by which deterioration in the soldering properties in the surface of the film is prevented. This quaternary compd. is represented by the formula. In the formula, R1, R2, R3 and R4 denote a substituted or nonsubstituted alkyl group, a substituted or nonsubstituted alkenyl group, a substituted or nonsubstituted aryl group or a substituted or nonsubstituted aralkyl group, and R1 and R2 and R3 and R4 may mutually form rings. Z+ denotes a nitrogen atom, a phosphorus atom, an arsenic atom or an antimony atom, and X- denotes an anion such as a chloride ion. As the soluble tin salt, a tin alkanesulfonate, or the like, such as tin methanesulfonate can be examplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tin plating bath and tin-silver, tin-zinc, tin-copper, tin-lead, tin-nickel,
The present invention relates to tin alloy plating baths such as tin-cobalt, tin-bismuth, tin-antimony, and tin-indium alloys. In particular, tin and tin alloy plating baths as materials for electric and electronic parts and the like that require solderability and plating thereof The present invention relates to a tin and tin alloy plating film formed using a bath and an electric / electronic component having the same, such as a lead frame for a semiconductor device.

[0002]

2. Description of the Related Art Tin plating and tin alloy plating such as tin-lead and tin-zinc have good corrosion resistance and solderability. Widely used as industrial plating.
Various plating baths have been developed for use in tin plating and alloy plating of tin-lead, tin-zinc and the like.
In general, these plating baths contain organic compounds such as surfactants and various additives to prevent the plating film from becoming resinous and to devise a plating film having a practical surface. are doing. For example, those having a characteristic surfactant (JP-A-8-13185) and those having improved solderability under a wide range of current density conditions (JP-A-10-25)
595).

[0003]

However, such conventional techniques have not sufficiently solved the practical problem of solderability. In recent years, the performance of various electronic devices and the like has become more sophisticated, and strict requirements have been placed on the characteristics of semiconductor devices used therein for each year. In particular, in a lead frame of a pre-plating method in which a partial Ag plating of an inner lead portion for mounting a semiconductor chip and a tin alloy plating of an outer lead portion to be joined to an external electronic component are formed in advance, due to a heat history at the time of mounting the semiconductor chip, The solderability of tin alloy plating decreases. For this reason, the tin alloy plating materials used for these materials must have higher performance and have stable physical properties, and the demand for tin alloy plating baths is increasing.

FIG. 1 is a plan view showing an example of a lead frame, and FIG. 2 is a sectional view showing an example of a lead frame.
1 and 2, 1 is a chip mounting portion, 2 is an inner lead portion, 3 is an outer lead portion, 4 is a tie bar portion, 5
Is a semiconductor chip, 6 is an adhesive, 7 is an electrode pad, 8 is a wire, and 9 is a sealing resin. In the lead frame, the inner lead portion 2 is preliminarily plated with Ag and the outer lead portion 3 is plated with tin alloy, the semiconductor chip 5 is bonded to the chip mounting portion 1, and the terminals of the semiconductor chip 5 and the inner lead portion 2 are connected by wires. Then, the entire structure other than the outer lead portion 3 is sealed with a sealing resin 9.

[0005] A plan view of the lead frame shown in FIG.
Only the lead frame before the bonding of the semiconductor chip 5, the bonding with the wire 8, and the sealing with the sealing resin 9 is shown.
, Bonding with the wire 8, and sealing with the sealing resin 9, the corresponding inner lead portion 2 and the outer lead portion 3 are electrically connected, and the adjacent inner lead portions 2 are connected to each other. The lead frame is cut so that the lead portions 3 are not short-circuited. Thereafter, the outer lead portion 3 is joined to another electronic component by solder and used.

In particular, in the pre-plating method in which a plating film is formed on both the inner lead portion 2 and the outer lead portion 3 in advance, the solderability of the tin alloy plating is reduced due to the heat history at the time of mounting the semiconductor chip, and the solderability in the subsequent process is reduced. This leads to a decrease in solder wettability, which impairs the soldering performance of the outer lead portion 3 exposed to the outside after sealing with the sealing resin 9. That is, the wetting speed decreases, and it becomes difficult to cover the required solder wetting area. For this reason, the immersion time in the solder bath increases, the work efficiency decreases, and in extreme cases, the solder does not wet at all. There was a problem that. In particular, with the recent increase in the density of semiconductor devices, the spacing between the outer lead portions 3 has become narrower, and the solderability due to the poor solderability of tin alloy plating during reflow (remelting) joining with cream solder in surface mounting has been There is a problem that the current flows in the lateral direction of the substrate, a bridge is generated between the wirings, and the circuit is short-circuited.
Although it is possible to reduce the bridge generation to some extent by reducing the amount of the cream solder applied, on the other hand, the reduction in the amount of cream solder applied lowers the height of the cream solder application, resulting in a gap between the outer lead portion 3 and the substrate. May cause no joining at all, and the circuit may be opened.

The present invention solves the above-mentioned conventional problems. Tin and tin alloy plating films having good solderability, and in particular, having excellent soldering performance in which these characteristics are not easily deteriorated by heat history. It is an object of the present invention to provide a tin and tin alloy plating bath for obtaining the same, and a plating film formed using the plating bath.

[0008]

In order to solve the above-mentioned problems, a tin and tin alloy plating bath of the present invention comprises a soluble tin salt,
And a graded compound.

With this configuration, the solder wettability is good,
It is possible to provide a tin and tin alloy plating film having a high solder wetting rate and excellent soldering performance in which these characteristics are hardly deteriorated by a heat history, and a tin and tin alloy plating bath for obtaining the film. .

[0010]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention is a tin plating bath containing (a) a soluble tin salt and (b) a quaternized compound. The tin plating film thus formed has an effect of preventing the deterioration of the solderability on the surface of the plating film by oxidizing the quaternized compound due to the heat history.

According to a second aspect of the present invention, in the first aspect, the quaternized compound is a compound represented by the following general formula (Formula 1). This is a tin plating bath, and a tin plating film formed using the bath has an effect of preventing a decrease in solderability on the surface of the plating film by oxidizing a quaternized compound due to heat history. .

The invention described in claim 3 of the present invention is characterized in that (a)
A soluble tin salt; (b) a soluble salt of at least one metal selected from silver, zinc, copper, lead, nickel, cobalt, bismuth, antimony, and indium; and (c) a quaternized compound; Is a tin alloy plating bath containing a tin alloy plating film. The quaternized compound is oxidized by the thermal history of the tin alloy plating film, thereby preventing a decrease in solderability on the surface of the plating film. It has the effect of doing.

According to a fourth aspect of the present invention, in the third aspect, the quaternized compound is a compound represented by the following general formula (Chemical Formula 2). This is a tin alloy plating bath. The tin alloy plating film formed by using the bath prevents the deterioration of solderability on the surface of the plating film by oxidizing the quaternized compound due to the heat history. Having.

According to a fifth aspect of the present invention, there is provided a tin plating film formed by using the tin plating bath according to any one of the first to second aspects. Oxidation of the quaternized compound due to the history has the effect of preventing a decrease in solderability on the surface of the plating film.

According to a sixth aspect of the present invention, there is provided a tin plating film formed by using the tin plating bath according to any one of the third to fourth aspects. The oxidized compound has an effect of preventing a decrease in solderability on the surface of the plating film.

According to a seventh aspect of the present invention, a tin plating film formed by using the tin plating bath according to the first or second aspect is formed on at least an outer lead portion. This lead frame has a function of preventing a decrease in solderability on the surface of a plating film by oxidizing a quaternized compound due to thermal history.

According to an eighth aspect of the present invention, a tin plating film formed by using the tin plating bath according to the third or fourth aspect is formed on at least an outer lead portion. This lead frame has a function of preventing a decrease in solderability on the surface of a plating film by oxidizing a quaternized compound due to thermal history.

Hereinafter, embodiments of the present invention will be described.

(Embodiment 1) The soluble tin salts usable in the present invention include tin alkane sulfonates such as tin methanesulfonate and tin ethanesulfonate, and tin alkanol sulfonates such as tin isopropanol sulfonate. ,
Stannous chloride, stannous oxide, stannic oxide, stannous sulfate, stannous acetate, stannous sulfamate, stannous pyrophosphate,
It is at least one selected from stannous gluconate, stannous tartrate, sodium stannate, potassium stannate and the like. 5 to 200 g / l of the above tin salt as a tin metal concentration,
Preferably, the amount is 10 to 100 g / l. If less than 5 g / l, the plating rate is too low to obtain a normal film,
If the plating rate is increased by increasing the current density, burning occurs and a normal film cannot be obtained, which is not practical. Also, 200g
If it is more than / l, the consumption of tin metal due to pumping out of the liquid is large and it is not economical. These salts may be used alone or in combination of two or more.

The quaternized compound has the following general formula (Formula 1)
In the formula, R1, R2, R3,
R4 represents an alkyl group (eg, methyl group, ethyl group, propyl group, butyl group, etc.), an alkenyl group (eg, vinyl group, propenyl group, allyl group, etc.), an aryl group (eg, phenyl group, naphthyl group, etc.), or aralkyl Represents a group (benzyl group, phenethyl group, etc.), and these groups may be substituted. Examples of the substituent include a halogen atom (eg, chlorine, bromine, etc.) and an alkyl group (eg, a methyl group, an ethyl group, a propyl group) Butyl group), nitro group and the like. R1 and R2, and R3 and R4 may form a ring with each other. Z represents a nitrogen atom, a phosphorus atom, an arsenic atom or an antimony atom, and X- represents an anion.
Examples of the anion represented by X- include a chloride ion, a bromide ion, an iodide ion, a nitrite ion, a hypochlorite ion, a benzenesulfonic acid ion, a hydroxide ion and the like.

Specific representative examples of the compounds represented by the above general formulas (Chemical Formula 1) and (Chemical Formula 2)
8),

[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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The compounds used in the present invention are not limited to these.

The compounds represented by the above-mentioned general formulas (Chemical Formula 1) and (Chemical Formula 2) have a concentration in the plating bath of 10 to 1000 ppm, preferably 50 to 500 ppm, based on the metal tin, in terms of the Z concentration.
ppm is good.

The alloy component is at least one metal selected from silver, zinc, copper, lead, nickel, cobalt, bismuth, antimony, and indium. The soluble salt of the alloy component is, for example, a soluble salt of silver. Examples thereof include silver methanesulfonate, silver ethanesulfonate, silver isopropanolsulfonate, silver oxide, silver chloride, silver nitrate, and silver acetate.
As soluble salts of zinc, zinc methanesulfonate, zinc ethanesulfonate, zinc isopropanolsulfonate,
Zinc chloride, zinc nitrate, zinc carbonate, zinc sulfate, zinc pyrophosphate, etc. are soluble salts of copper such as copper methanesulfonate, copper ethanesulfonate, copper isopropanolsulfonate, copper sulfate, cupric oxide, copper nitrate , Cuprous chloride, cupric chloride, copper carbonate, copper pyrophosphate, copper sulfamate, etc.
Examples of soluble salts of lead include lead methanesulfonate, lead ethanesulfonate, lead isopropanolsulfonate, lead acetate,
Examples of soluble salts of nickel include lead nitrate, lead carbonate, lead sulfamate, etc .; nickel methanesulfonate, nickel sulfate, nickel formate, nickel chloride, nickel sulfamate, nickel acetate; Cobalt sulphonate, cobalt sulphate, cobalt chloride, cobalt acetate and the like, and as soluble salts of bismuth, bismuth methanesulphonate, bismuth sulphate, bismuth gluconate, bismuth nitrate, bismuth oxide, bismuth carbonate, bismuth chloride, etc. The soluble salts include antimony methanesulfonate, antimony chloride, potassium antimonyl tartrate, potassium pyroantimonate, antimony tartrate, and the like. The soluble salts of indium include indium methanesulfonate, indium sulfamate, and indium sulfate. Um, indium oxide, respectively.

Various surfactants are added to the above-mentioned plating bath to obtain a smooth plating film, to enhance outgassing during plating and to prevent pits. As the surfactant, a nonionic surfactant, an amphoteric surfactant, a cationic surfactant, and an anionic surfactant can be used. These surfactants can be used alone or in combination of these various surfactants, and the added amount is 1 to 300 g /
l, preferably 10 to 100 g / l.

Examples of the nonionic surfactant include polyalkylene glycol, higher alcohol, alkylphenol, alkylnaphthol, bisphenols, styrenated phenol, fatty acid, aliphatic amine, alkylenediamine, aliphatic amide, sulfonamide, and polyhydric alcohol. And polyoxyalkylene adducts such as glucoside.

Examples of the amphoteric surfactant include betaine,
Sulfobetaine, aminocarboxylic acid, imidazolium betaine and the like can be mentioned.

Examples of the cationic surfactant include dodecyl trimethyl ammonium salt, hexadecyl trimethyl ammonium salt, octadecyl trimethyl ammonium salt, dodecyl dimethyl ethyl ammonium salt, dodecyl dimethyl ammonium betaine, octadecyl dimethyl ammonium betaine, hexadecyl pyridinium salt and the like. No.

Examples of the anionic surfactant include alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, and alkyl naphthalene sulfonates.

If necessary, a complexing agent may be added to the plating bath.
Various additives such as antioxidants, brighteners, and stress reducers can be added. Complexing agents include ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, gluconic acid, citric acid, glycine, tartaric acid, thiophenol, mercaptopyridine, 4,4-thiodiphenol, 2,2
-Dipyridyl disulfide and the like; antioxidants such as catechol, hydroquinone and pyrogallol; brighteners such as thiourea, 1,4-butynediol and sodium 3-mercapto-1-propanesulfonate; stress-reducing agents such as Naphtholsulfonic acid, sodium 1,5-naphthalenedisulfonic acid, and the like.

Further, in the present invention, the temperature of the plating bath is 10
-40 ° C., preferably 20-30 ° C., the pH of the plating bath is 1 or less to about 12 and the cathode current density is 1 to 50 A
/ Dm ² , preferably 5 to 30 A / dm ² .

[0048]

Next, specific examples of the present invention will be described.

Example 1 The following compounds were sequentially mixed in a container, pure water was added to a specified amount, the prepared plating bath was stirred, and the liquid temperature was adjusted to 25 ° C. Adjust the liquid temperature as needed,
The test was performed using a heater and a cooler. 15mm × 30
mm on a copper plate, platinum-titanium (Pt / Pt) as anode
Using electrode, while spraying plating solution, solution flow rate 8l / m
The plating was performed in. 165 ° C
And then dipped in flux (isopropanol solution containing 25% rosin) for 5 seconds, then dipped in a solder bath (Sn-Pb eutectic solder) kept at 230 ° C for 5 seconds, and washed with isopropyl alcohol Thereafter, the solderability was evaluated based on the degree of solder wetting on the surface. Solderability was evaluated as follows: ◎ when 98% or more wet, ○ when 90% or more wet, Δ when 80% or more wet,
When the degree of wetting was less than 80%, it was evaluated as x.

Tin (II) methanesulfonate (as tin metal) 50 g / l Methanesulfonic acid (free acid) 80 g / l Nonylphenol polyethoxylate (EO15) 20 g / l Catechol 1 g / l 200 ppm (as a concentration with respect to Pd) (Example 2) A trial product was manufactured and evaluated in the same manner as described in Example 1 except for the composition of the plating bath.

Tin (II) 2-hydroxypropanesulfonate (as tin metal) 50 g / l 2-hydroxypropanesulfonic acid (free acid) 80 g / l Octylphenol polyethoxylate (EO10) 20 g / l Hydroquinone 0.5 g / l (Chemical Formula 10) (as the concentration of Z with respect to metal Pd) 100 ppm (Example 3) A prototype was made in the same manner as described in Example 1 except for the composition of the plating bath, and evaluation was performed.

Tin (II) methanesulfonate (as tin metal) 50 g / l Silver (I) methanesulfonate 1 g / l Methanesulfonic acid (free acid) 80 g / l 4,4-thiodiphenol 2 g / l Bisphenol A Dipolyethylene glycol ether 20 g / l Catechol 1 g / l (Chemical formula 11) (as the concentration of Z with respect to metal Pd) 100 ppm (Example 4) A prototype was made in the same manner as described in Example 1 except for the composition of the plating bath, and evaluated. Was carried out.

Tin (II) sulfate (as tin metal) 40 g / l Zinc (II) sulfate 7 g / l Sodium gluconate 300 g / l Ammonium sulfate 150 g / l Nonylphenol polyethoxylate (EO15) 10 g / l Hydroquinone 0.5 g / l (Chemical Formula 4) (as the concentration of Z with respect to metal Pd) 200 ppm (Example 5) A trial product was manufactured and evaluated in the same manner as described in Example 1 except for the composition of the plating bath.

Tin (II) sulfate (as tin metal) 40 g / l Copper (II) sulfate 20 g / l Ammonium citrate 320 g / l Ammonium sulfate 260 g / l Octylphenol polyethoxylate (EO10) 10 g / l Catechol 1 g / l 10) (as the concentration of Z with respect to metal Pd) 100 ppm (Example 6) A prototype was made and evaluated in the same manner as described in Example 1, except for the composition of the plating bath.

Tin (II) methanesulfonate (as tin metal) 50 g / l Lead (II) methanesulfonate 6 g / l Methanesulfonic acid (free acid) 150 g / l Bisphenol A dipolyethylene glycol ether 20 g / l Hydroquinone 0. 5 g / l (Formula 11) 100 ppm (as the concentration of Z with respect to metal Pd) (Example 7) A trial production was performed in the same manner as described in Example 1 except for the composition of the plating bath, and evaluation was performed.

Tin (II) chloride (as tin metal) 56 g / l Nickel (I) chloride 60 g / l Potassium pyrophosphate 400 g / l Glycine 40 g / l Nonylphenol polyethoxylate (EO15) 20 g / l Hydroquinone 0.5 g / l (Formula 4) 200 ppm (as the concentration of Z with respect to metal Pd) (Example 8) A trial production was performed in the same manner as described in Example 1 except for the composition of the plating bath, and evaluation was performed.

Tin (II) sulfate (as metallic tin) 20 g / l Cobalt sulfate heptahydrate (II) 8.5 g / l Citric acid 150 g / l Ammonium sulfate 100 g / l Octylphenol polyethoxylate (EO10) 20 g / l Catechol 1 g / l (Chemical Formula 10) (as the concentration of Z with respect to metal Pd) 100 ppm (Example 9) A trial production was performed in the same manner as described in Example 1 except for the composition of the plating bath, and evaluation was performed.

Tin (II) methanesulfonate (as tin metal) 50 g / l Bismuth (III) methanesulfonate 6 g / l Methanesulfonic acid (free acid) 150 g / l Bisphenol A dipolyethylene glycol ether 20 g / l Hydroquinone 0. 5 g / l (Chemical Formula 11) 100 ppm (as the concentration of Z with respect to metal Pd) (Example 10) A trial production was performed in the same manner as described in Example 1 except for the composition of the plating bath, and evaluation was performed.

Tin (II) methanesulfonate (as tin metal) 50 g / l Antimony (III) chloride 5 g / l Methanesulfonic acid (free acid) 120 g / l Nonylphenol polyethoxylate (EO15) 20 g / l Catechol 1 g / l (Chemical Formula 10) 100 ppm (as the concentration of Z with respect to metal Pd) (Example 11) A prototype was made and evaluated in the same manner as described in Example 1 except for the composition of the plating bath.

Tin (II) methanesulfonate (as tin metal) 50 g / l Indium chloride tetrahydrate (III) 40 g / l Methanesulfonic acid (free acid) 150 g / l Tartaric acid 150 g / l Bisphenol A dipolyethylene glycol Ether 20 g / l Hydroquinone 0.5 g / l (Formula 11) 100 ppm (as the concentration of Z with respect to metal Pd) (Comparative Example 1) A trial production was performed in the same manner as described in Example 1 except for the composition of the plating bath, and the evaluation was performed. Carried out.

Tin (II) methanesulfonate (as tin metal) 50 g / l Methanesulfonic acid (free acid) 80 g / l Nonylphenol polyethoxylate (EO15) 20 g / l Catechol 1 g / l (Comparative Example 2) Except for the composition, a prototype was manufactured and evaluated in the same manner as described in Example 1.

Tin (II) methanesulfonate (as tin metal) 50 g / l Silver (I) methanesulfonate 1 g / l Methanesulfonic acid (free acid) 80 g / l 4,4-thiodiphenol 2 g / l Bisphenol A Dipolyethylene glycol ether 20 g / l Catechol 1 g / l (Comparative Example 3) A prototype was produced and evaluated in the same manner as described in Example 1 except for the composition of the plating bath.

Tin (II) sulfate (as tin metal) 40 g / l Zinc (II) sulfate 7 g / l Sodium gluconate 300 g / l Ammonium sulfate 150 g / l Nonylphenol polyethoxylate (EO15) 10 g / l Hydroquinone 0.5 g / l (Comparative Example 4) A trial product was manufactured and evaluated in the same manner as described in Example 1 except for the composition of the plating bath.

Tin (II) methanesulfonate (as tin metal) 50 g / l Bismuth (III) methanesulfonate 6 g / l Methanesulfonic acid (free acid) 150 g / l Bisphenol A dipolyethylene glycol ether 20 g / l Hydroquinone 0. 5 g / l In Example 1, a uniform plating film of about 10 μm was obtained in a cathode current density of 25 A / dm ² and a plating time of 30 seconds. In Examples 2 to 11, tin and tin alloy plating films having good cathode current densities were obtained. Examples 1 to 1
1, Table 1 shows the evaluation results of Comparative Examples 1 to 3.

[0065]

[Table 1]

The plating film obtained in Example 1 had good solderability. Hereinafter, in Examples 2 to 11, there is an appropriate current density range, but as in Example 1, good solderability was obtained. On the other hand, in Comparative Examples 1 to 4, good solderability was not obtained.

Next, a trial production was performed by replacing the plating object with a lead frame.

Example 12 Using the plating bath of Example 1, a platinum-titanium (Pt / Pt) electrode was used as an anode on a lead frame made of a copper material, and a plating solution was sprayed at a solution flow rate of 8 l / min. Plating was performed. After heating the obtained plating film at 165 ° C. for 2 hours, only the outer lead portion of the lead frame was cut and mounted on an apparatus, and the JIS C
According to the soldering test method according to the prescribed equilibrium method, the zero-crossing time, which is the time when the zero force acting at the time when the solder surface first contacts the sample and the sample begins to wet after receiving buoyancy, becomes zero again. It was measured. The flux used a 25% rosin-containing isopropanol solution, the solder bath was maintained at 230 ° C., and Sn-Pb eutectic solder was used. When the zero cross time is 2 seconds or less, the solderability is good, but when the zero cross time is 5 seconds or more, the solder is hardly wet and the solderability is poor.

Example 13 Using the plating bath of Example 3, a prototype was produced in the same manner as described in Example 12, and an evaluation was performed.

Example 14 Using the plating bath of Example 4, a prototype was produced in the same manner as described in Example 12, and an evaluation was performed.

(Example 15) Using the plating bath of Example 9, a prototype was produced in the same manner as described in Example 12, and evaluation was performed.

(Comparative Example 5) Using the plating bath of Comparative Example 1, a prototype was produced and evaluated in the same manner as described in Example 12.

(Comparative Example 6) Using the plating bath of Comparative Example 2, a prototype was produced and evaluated in the same manner as described in Example 12.

(Comparative Example 7) Using the plating bath of Comparative Example 3, a prototype was produced in the same manner as described in Example 12, and evaluation was performed.

(Comparative Example 8) Using the plating bath of Comparative Example 4, a prototype was produced and evaluated in the same manner as described in Example 12.

In Example 12, the cathode current density 25
A uniform plating film of about 10 μm was obtained at A / dm ² and a plating time of 30 seconds. In Examples 13 to 15, good tin alloy plating films were obtained at the respective cathode current densities. The evaluation results of Examples 12 to 15 and Comparative Examples 5 to 8 are shown in (Table 2).

[0077]

[Table 2]

The lead frame obtained in Example 12 had good solderability. Examples 13 to
Although each of the samples No. 15 and S15 had an appropriate current density range, good solderability was obtained as in Example 12. On the other hand, in Comparative Examples 5 to 8, good solderability was not obtained.

In the present embodiment, the tin and tin alloy plating on the lead frame made of a copper material is described. However, the same result as that of the copper material was obtained for the tin and tin alloy plating on the lead frame made of 42 alloy.

Although the above embodiments have described tin and tin alloy plating on a lead frame, the present invention is not limited to this application.

[0081]

As described above, the tin and tin alloy plating baths of the present invention have good solderability by containing a soluble tin salt and a quaternized compound. Has an advantageous effect of obtaining a tin and tin alloy plating film having excellent soldering performance which does not deteriorate in a high-temperature environment, and an advantageous effect of obtaining a plated material in which plating is optimized. Is obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a lead frame.

FIG. 2 is a sectional view showing an example of a lead frame.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chip mounting part 2 Inner lead part 3 Outer lead part 4 Tie bar part 5 Semiconductor chip 6 Adhesive 7 Electrode pad 8 Wire 9 Sealing resin

Claims (8)

[Claims] 1. A tin plating bath containing (a) a soluble tin salt and (b) a quaternized compound. 2. The quaternized compound is represented by the following general formula (Chemical Formula 1). The tin plating bath according to claim 1, which is a compound represented by the formula: (3) a soluble tin salt, (b) silver, zinc,
Copper, lead, nickel, cobalt, bismuth, antimony,
A tin alloy plating bath containing a soluble salt of at least one metal selected from indium and (c) a quaternized compound. 4. The quaternized compound is represented by the following general formula (2). The tin alloy plating bath according to claim 3, which is a compound represented by the formula: 5. A tin plating film formed by using the tin plating bath according to claim 1. 6. A tin plating film formed by using the tin plating bath according to claim 3. 7. A lead frame for a semiconductor device, wherein a tin plating film formed by using the tin plating bath according to claim 1 is formed on at least an outer lead portion. 8. A lead frame for a semiconductor device, wherein a tin plating film formed using the tin plating bath according to claim 3 is formed on at least an outer lead portion.