JP2677760B2 - Solder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tin-lead alloy solder.

[0002]

2. Description of the Related Art Since tin-lead alloy solder melts at a low temperature, it has long been used as a convenient material for a wide range of purposes. A tin-lead alloy solder containing tin and lead as main components and having a third metal added thereto to improve the properties has been reported. For example, Japanese Examined Patent Publication No. 40-25885 and Japanese Examined Patent Publication No. 45
-2093, JP-A-48-97752, JP-A-51-54056, and JP-A-54-72738.
JP-B, JP-B-55-18505, JP-A-56-
No. 144893, Japanese Patent Publication No. 57-39880,
JP-A-60-166191, JP-A-61-829
94, JP 61-269998, JP 61-115692, JP 3-32487, JP 3-106591, JP 3-204.
193, JP-A-3-204194, JP-A-4-333392, JP-B-49-21028, JP-A-54-72738, JP-A-59-70.
490, JP-B-49-23986, JP-A-57-160594, JP-A-63-313689.
JP, JP-A-53-113245, JP-A-58
No. 218394 is known. Among the above-mentioned prior arts, only the Japanese Patent Publication No. 57-39880 discloses the compounding of phosphorus in the tin-lead alloy solder, and the other ones do not disclose phosphorus at all. Tokiko 57
No. 39980 discloses a tin-lead alloy solder containing cadmium, which is suitable for soldering an electronic component having a gold or silver film. The addition of cadmium causes an increase in the surface oxidation of the molten solder, which reduces the wettability and spreadability of the solder. It is described that phosphorus suppresses the surface oxidation of the molten solder, improves the wettability, and prevents defects caused by the inclusion of oxide during solidification of the solder and suppresses the decrease in mechanical strength.

[0003]

In recent years, soldering has been exposed to heat and stress as a result of the progress of high-density mounting such as surface mounting. Therefore, the conventional tin-lead alloy solder has a bonding strength. There have been insufficient cases. In particular, the development of solders that exhibit high reliability under conditions where fatigue damage is likely to occur, such as automobile substrates and substrates on which heat-generating components are mounted, is awaited.

[0004]

The present invention is directed to lead 15-80.
% By weight, silver 0.1-5% by weight, antimony 0.1-0.8
Provided is a tin-lead alloy solder consisting essentially of wt%, phosphorus 0.0005 to 0.01 wt% and the balance of tin.

In the present invention, when phosphorus is used in combination with silver and antimony, the fatigue characteristics of the soldered portion,
It is especially effective in improving the thermal fatigue property.

The tin-lead alloy solder of the present invention contains lead in an amount of 15 to 80% by weight, generally 30 to 60% by weight based on the total weight of the solder. If the lead content is too low or too high, the melting point rises, which is not suitable for soldering electronic materials. Lead may be partially replaced with a metal selected from the group consisting of cadmium, bismuth, indium, zinc and copper and gallium. The amount of these metals is 0.1-0.1% of the total weight of solder.
22% by weight, cadmium, bismuth and indium, preferably 5 to 22% by weight. These metals are preferably 30% by weight or less of lead. Even in that case, the content of lead is 15% by weight or more, preferably 30% by weight of the total amount of solder.
It is preferable that this is the case. You may use 2 or more types of these metals.

A solder in which a portion of 15 to 80% by weight of lead is replaced with one or more metals selected from cadmium, bismuth, indium, zinc and copper and gallium. The content of the replaced components is approximately half (70%) or less of the lead content (% by weight) and / or 0.1 to 22% by weight. Cadmium, bismuth and indium are used for the purpose of lowering the melting point of the solder, but cadmium is toxic, bismuth makes the solder brittle, and gallium and indium are expensive, so the amount used is preferably as small as possible. Effective doses of cadmium are 5-22% by weight, bismuth is 5-22% by weight, and indium is 0.1-0.1%.
It is 22% by weight.

Zinc and copper are effective in improving the material strength, and zinc is also used for the purpose of anticorrosion. Addition of a large amount of both metals causes the melting point to rise, so the amount used is 22% by weight.
Hereafter, the amount of effective efficacy is 0.1 to 10% by weight, more preferably 0.1 to 5% by weight.

Although gallium is used for the purpose of preventing the oxidation of solder, it is easily oxidized and if used in a large amount, soldering failure occurs, so 0.001 to 1% by weight, particularly 0.001 to 0.5. Weight percent is suitable.

In the present invention, silver is used in an amount of 0.1 to 5% by weight for the purpose of increasing the material strength of the solder itself. However, if it is 0.1% by weight or less, it has no effect, and if it is 5% by weight or more, it is an infusible metal. Since intermetallic compounds are generated, the flowability and solderability are deteriorated, which is not suitable for precision soldering. The optimum effective use amount is 0.3 to 4% by weight, more preferably 0.5 to 3% by weight.

In the present invention, antimony is important for increasing the material strength of solder, but if it is less than 0.1% by weight, the manifestation of the effect is not remarkable. If it exceeds 10% by weight, an infusible component is produced, which is not suitable for precise soldering. A more preferred amount used is 0.2 to 7% by weight, more preferably 0.3 to 3% by weight.

A portion of 0.1 to 10% by weight of antimony is selected from aluminum, gold, magnesium, cerium, platinum, palladium, cobalt, chromium, manganese, zircon, germanium, nickel, tellurium, etc. 1
Solder that is replaced with more than one kind of metal. The content of the replaced components is about half (70%) of the antimony content (% by weight).
%) Or less and / or 0.001 to 3% by weight. A part of antimony may be replaced with a metal selected from the group consisting of aluminum, gold, magnesium, cerium, platinum, palladium, cobalt, chromium, manganese, zircon, germanium, nickel, and tellurium, and may be blended. The compounding amount is 3% by weight or less based on the total weight of the solder. The amount of effective efficacy is 0.001% by weight or more based on the total weight of the solder. However, the amount of these metals added is 30 for antimony.
% Or less, more preferably 10% or less. Even in this case, the antimony content is 0.1% by weight or more, preferably 0.2% by weight or more based on the weight of the solder. Two or more kinds of these metals may be used in combination.

Aluminum is used for the purpose of preventing the oxidation of the solder, but since it is easily oxidized and a large amount of aluminum causes soldering failure, 0.001-1
%, Especially 0.001-0.5% by weight is suitable.

Platinum, palladium, cobalt, chromium, manganese, nickel, tellurium, zircon, germanium and the like may be used for the purpose of precipitation strengthening or finer graining, but since they are infusible components, they exhibit the effect. A suitable amount is 0.001-1% by weight, particularly preferably 0.001.
~ 0.5% by weight.

In the present invention, phosphorus is used to improve the thermal fatigue properties of the tin-lead alloy solder, especially the tin-lead alloy solder containing silver and antimony. The amount of phosphorus used is 0.0005 to 0.3% by weight, and more preferably 0.0005 to 0.1% by weight, based on the total amount of solder. Especially preferred is 0.
It is 001-0.05%. If the phosphorus content is less than 0.0005% by weight, there is no effect, and if it exceeds 0.1%, the thermal fatigue property is not improved, and if it is more than 0.3% by weight, the fluidity decreases due to the reaction product of tin and phosphorus. Or characteristic deterioration occurs.

Tin is the remaining component of the tin-lead alloy solder and is usually used in an amount of 10 to 85% by weight. This corresponds to the tin content of conventional general tin-lead alloy solder. Tin content is 1
If it is less than 0% by weight or more than 85% by weight, the melting point of the solder rises, it becomes unsuitable for soldering of electronic materials, and oxidation becomes remarkable due to the high melting temperature. Further, the decrease in the tin content leads to an increase in the amount of lead compositionally, which leads to a decrease in the material strength and an accelerated formation of the α layer. On the other hand, increasing the amount of lead is effective in suppressing the formation of the tin-copper layer at high temperatures, and the compounding ratio of these should be selected based on the object of use, the conditions of use, and the like. Increasing the amount of tin increases the cost and reduces the effect of adding silver.

The solder to which phosphorus is added is
Improves solderability. The present invention further relates to cream solder containing the above solder powder. The cream solder of the present invention contains a flux component, that is, a resin, an activator, a viscosity modifier, a solvent and the like in addition to the solder powder.

The solder powder preferably has an average particle size of 5-10.
It is 0 μm, more preferably 15 to 50 μm. The particle shape may be any shape such as a substantially perfect spherical shape, a flat block shape, a needle shape, and an amorphous shape, and may be appropriately selected depending on the required properties of the cream solder such as thixotropy and sagging resistance.

The content of the solder powder is 80 to 95% by weight, more preferably 85 to 92% by weight based on the total weight of the cream solder.
It is.

As the resins that can be blended in the cream solder, any of the resins generally used in the conventional tin / lead-based solder resins can be used. Examples of typical resins are rosin,
Examples include disproportionated rosin, hydrogenated rosin, maleated rosin, polymerized rosin, and purified rosin. Particularly preferred resins for the purposes of the present invention are polymerized rosins.

The amount of the resin compounded is preferably 20 to 80% by weight, more preferably 40 to 60% by weight, based on the total amount of the flux.

As the activator, any of those generally used in conventional tin / lead solders may be used.
Specific examples thereof include organic acids such as adipic acid, sebacic acid and salicylic acid. Further, amine amino alcohols such as triethanolamine can be exemplified.
Hydrohalic acids of amines such as ethylamine HB
Examples include r, aniline HBr, cyclohexylamine HCl, cyclohexylamine HBr, and the like. These activators are preferably used in an amount of usually 0 based on the total weight of the flux.
10 to 10% by weight, more preferably 0.5 to 3% by weight.

As the viscosity modifier, ester type substances, for example, hardened oil such as coconut oil, beef tallow, castor oil, whale oil, rapeseed oil, semi-hardened oil, hollow, beeswax, candelilla wax, carnauba wax, etc .; free acids, For example, cork acid, azelaic acid, sebacic acid, dodecanedioic acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, coconut oil fatty acid beef tallow fatty acid, rapeseed oil fat, montanic acid, benzoic acid, phthalic acid, trimellitic acid. Polyalkylene glycols such as polyethylene glycol wax, high molecular weight polyethylene wax and waxes such as higher fatty acid and polycarboxylic acid; polyolefins such as copolymers of polyethylene, polypropylene, butadiene, butene, isoprene, etc .; inorganic Or organic pigments, eg If bentonite, organic bentonite, micronized silica, aluminum, stearate and the like; amides such as stearamide, ethylene bis stearamide, such as oleyl are exemplified. Particularly suitable viscosity modifiers are hydrogenated castor oil and amide wax.

The amount of the viscosity modifier used is preferably 0.1 to 10% by weight, more preferably 2 to 7% by weight, based on the total amount of the flux.

Examples of the solvents include alkylene glycols and the like. A particularly suitable solvent is propylene glycol monophenyl ether and the like.

The amount of the solvent blended is preferably 20 to 80% by weight, more preferably 35 to 65% by weight, based on the total weight of the flux.

In addition to the above-mentioned components, the cream solder of the present invention may be appropriately blended with antioxidants and the like which are used in ordinary tin / lead type cream solders. The flux content of the cream solder is 6 to 25%, preferably 8 to 12%. If it is less than 6%, it will not be a paste. If it is 25% or more, the amount of solder is not sufficient.

The solder of the present invention may be a solder containing a resin. The tar component used includes resins and activators.

The solder molded product is manufactured by flattening the wire solder with a roller or the like and then forming it by shirring, pressing or the like.

Further, the solder containing the resin was flatly crushed by a roller and then punched by a press to obtain a molded solder. Molded products that use solder containing resin are convenient because they do not require flux supply. The forming solder supplies the solder by placing the solder at a place where soldering is necessary.

Examples of the method of using the solder of the present invention include dip soldering with a solder bath, soldering with a solder with a solder containing solder, reflow soldering with cream solder, and placement soldering with molding solder.

Since the soldering is subject to various changes according to various manufacturing methods of the soldered product, the manufacturing method is not limited, and the solder of the present invention can be variously used. In addition, each solder product has a soldering method suitable for the intended use.

The present invention is not limited to the above, but relates to a joining method using the solder having the composition of the present invention.

Most of the soldering using the solder of the present invention is to join the conductor pattern of the printed wiring board to the electronic parts, terminals, heat sinks, transformers and the like.

The solder of the present invention is suitable for heating parts, large parts,
Excellent results are obtained in places where stress and heat are applied to the soldered parts such as heavy parts and fatigue tends to proceed.

Bonding using the solder of the present invention is generally Sn.
Compared to Pb-based solder, it exhibits excellent thermal fatigue resistance, so that the product life is extended. Hereinafter, an example will be described.

Examples and Comparative Examples Manufacture of tin-lead alloy solder : A predetermined amount of the components shown in Tables 1 to 4 were placed in a porcelain crucible and mixed in a nitrogen atmosphere while mixing.
It was heated and melted at 00 ° C. for 10 minutes to obtain a tin-lead alloy solder.

Thermal Fatigue Property Test : Using the tin-lead alloy solders shown in Tables 1 to 4, 100
Ten 10-pin connectors were soldered to a paper phenolic board (one-sided copper foil) of × 100 × 1.8 mm ³ at 240 ° C. This mounting mode is shown in FIG. In FIG. 1, (1) is solder, (2) is land (made of copper), (3) is phenol resin,
(4) shows a resin connector, and (5) shows a lead wire (pin).
This sample was placed in a hot air constant temperature bath at 80 ° C., kept for 30 minutes, placed at room temperature for 5 minutes, then placed in a constant temperature bath kept at −40 ° C., and kept for 30 minutes. This operation was repeated 200 cycles, and the number of pins with cracks was counted.

Crack generation rate = Number of cracks generated in phosphorus-containing sample / Number of cracks generated in phosphorus-free sample

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

[Table 4]

Examples 19 to 21 Fluxes for cream solder were prepared according to the formulations shown in Table 5. Separately, solder powder (Sn 62% by weight, Ag 0.3% by weight, Sb 0.7% by weight, Pb remaining%, and P50pp
m; average particle size of 325 to 660 mesh pass, manufactured by the rotating disk method) was prepared. The fluxes of Examples 19 and 20 were mixed with 10 parts by weight of each and 90 parts by weight of solder powder to obtain two types of cream solder.

[0045]

[Table 5] Further, the flux of Example 21 was subjected to cold extrusion to obtain a solder containing a flux having a flux content of 2% by weight.

[0046]

The tin-lead alloy solder of the present invention has excellent resistance to thermal fatigue.

[Brief description of the drawings]

FIG. 1 is a diagram showing a mounting mode of a sample used for a thermal fatigue characteristic test.

[Explanation of symbols]

(1) Solder, (2) Land part (copper foil), (3) Phenolic resin substrate, (4) Connector resin, (5) Pin

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Takashi Nagashima 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Akihiko Matsuo 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Meguro Sat. 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Kaoru Shimizu 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Hideo Chaki 3-8-10 Mitsuyachu, Yodogawa-ku, Osaka-shi, Osaka Prefecture Nihongenma Co., Ltd. (72) Inventor Toshiaki Ogura 3-8-10 Mitsuya-chu, Yodogawa-ku, Osaka City, Osaka (56) References (56) References JP 59-153857 (JP, A) JP 61-273296 (JP, A) JP 2-101132 (JP, A) JP 3-2556 37 (JP, A)

Claims (8)

(57) [Claims] 1. Tin-lead consisting essentially of lead 15-80 wt% silver 0.1-5 wt% antimony 0.1-0.8 wt% and phosphorus 0.0005-0.01 wt% tin balance. System alloy solder. 2. A part of lead is 0.1 to 22 of the total weight of solder.
The solder according to claim 1, which is replaced by a metal selected from the group consisting of cadmium, bismuth, indium, zinc, copper and gallium in an amount of 70% by weight (however, 70% by weight or less of lead). 3. The solder according to claim 1, wherein the phosphorus content is 0.0005 to 0.005% by weight. 4. The solder according to claim 1, which does not contain bismuth. 5. A cream solder containing the solder powder according to claim 1. 6. Formed solder using the solder according to claim 1. 7. A solder containing a solder using the solder according to claim 1. 8. A method of soldering a conductive pattern of a printed wiring board and a terminal portion of an electronic component, using the solder according to claim 1.