JPH11320177A - Solder composition material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain non leaded solder which is excellent in safety without containing Pb and has a characteristic equal to a Sn-Pb system solder referring to a soldering property and a Cu wire melting property by composing the solder with Sn and Bi as a main component and adding Cu at a given proportion. SOLUTION: This composition material contains, at wt.%, 5.0-90.0% Sn, 5.0-92.0% Bi, and 0.1% or more Cu. In this case, Cu satisfies the requirements that Cu additional volume (wt.%)<=(0.06×Sn volume)-0.02, and that Cu additional volume (wt.%)>=(0.06×Sn volume)-3.4. Furthermore, at least one chosen from a group of Ag, In, Zn, Sb, Ge, and P, is added to the solder composition material, so as to obtain the solder composition material having the more excellent characteristic referring to a soldering chatacteristic and a Cu wire melting property. The melting property of the Cu wire is evaluated by measuring the elapsed time from dipping the enamel coated Cu wire of 0.8 mm diameter in the solder bath of 400 deg.C till the wire is completely melted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder composition for electronic equipment and electronic components, and more particularly, to a solder composition suitable for use in performing both stripping and soldering of an enamel-coated copper wire at the same time. The present invention relates to a solder composition.

[0002]

2. Description of the Related Art Conventionally, in the manufacturing process of coil parts and the like, both enamel wire coating peeling and soldering of a winding coil have been performed at the same time. In such a case, the Pb content is high. 400 Sn-Pb solder
It has been common practice to use at temperatures as high as ° C. or higher.

[0003]

However, the conventional Sn-
Pb-based solder contains toxic Pb,
Its use is being restricted.

[0004] In recent years, so-called Pb-free solder (lead-free solder), which replaces Sn-Pb-based solder, has been distributed in the market, but most of them are mainly composed of Sn. If both the enamel wire coating peeling and the soldering are performed simultaneously, there is a problem that the so-called Cu wire biting phenomenon occurs in which the Cu wire dissolves in the solder.

[0005] The present invention solves the above-mentioned problems, and has at least the same characteristics as conventional Sn-Pb-based solders in terms of solderability and Cu line erosion resistance (Cu line erosion resistance). It is intended to provide a lead-free solder having the same.

[0006]

In order to achieve the above object, the solder composition of the present invention comprises Sn, Bi and Cu.
Sn: 5.0 to 90.0% by weight, Bi: 5.0 to 92.0% by weight, Cu: 0.1% by weight or more, and the following formulas (1) and (2)
It is characterized in that it is contained within the range that satisfies the requirements of. Cu addition amount (% by weight) ≦ (0.06 × Sn amount) −0.02 (1) Cu addition amount (% by weight) ≧ (0.06 × Sn amount) −3.4 (2)

[0007] Sn and Bi are the main components.
By mixing u in the above ratio, Pb is not contained, excellent in safety, and with respect to solderability and Cu wire erosion property, properties equivalent to conventional Sn-Pb-based solder are obtained. It becomes possible to obtain the solder which has.

In addition, the compounding ratio of Sn is adjusted to 5.0 to 90.0.
The reason for the range of the weight% is that when the compounding ratio of Sn is less than 5.0% by weight, the solderability decreases, and when it exceeds 90% by weight, the Cu wire is liable to be eroded.

Further, the mixing ratio of Bi is set to 5.0 to 92.0.
The range of the weight percent is that when the blending ratio of Bi is less than 5.0 wt%, the blending ratio of Sn inevitably increases and Cu
Line erosion is likely to occur, and conversely, if the content of Bi exceeds 92% by weight, the content of Sn inevitably decreases and solderability deteriorates.

The reason why the content of Cu is not less than 0.1% by weight and which satisfies the requirements of the above formulas (1) and (2) is as follows. That is, when the addition ratio of Cu is less than 0.1% by weight, the effect of suppressing Cu line erosion becomes insufficient, and when the requirement of the above formula (1) is not satisfied,
This is because the melting point of the solder exceeds 400 ° C., and it is practically impossible to use it. Further, when the requirement of the above formula (2) is not satisfied, it is impossible to suppress the Cu wire erosion.

The formula (1) is related to the mixing ratio of Sn.
FIG. 1 shows the compounding ratio of Cu in the solder composition of the present invention, defined by the formula (2). In FIG. 1, points A, B,
The region surrounded by C and D is the compounding ratio of Cu in the solder composition of claim 1.

Further, the solder composition according to claim 2 is characterized in that Sn,
Bi and Cu: Sn: 14.8 to 42.0% by weight Bi: 57.0 to 85.0% by weight Cu: 0.1% by weight or more, and the said 1st aspect.
It is characterized in that it is contained within a range that satisfies the requirements of formulas (1) and (2).

By mixing Sn, Bi, and Cu at the above-mentioned ratio, which is more limited than that of claim 1, P
It is possible to reliably obtain a solder composition which does not contain b, is excellent in safety, and has excellent characteristics with respect to solderability and Cu wire erosion resistance.

Further, the solder composition according to claim 3 is the same as the solder composition according to claim 1 or 2, further comprising Ag,
At least one selected from the group consisting of In, Zn, Sb, Ge, and P is added.

In addition to the above solder composition, Ag, I
By adding at least one of n, Zn, Sb, Ge, and P, Pb is not included, excellent in safety, and further excellent characteristics regarding solderability and Cu wire erosion. It becomes possible to obtain the solder composition which has.

Ag and Sb contribute to improving the solderability and mechanical strength of the solder, In and Zn contribute to controlling the melting point of the solder, and Ge and P contribute to suppressing the oxide film of the solder.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described, and features thereof will be described in more detail.

In this embodiment, a solder composition having a composition shown in Table 1 was prepared.

[0019]

[Table 1]

Sample Nos. 2, 4, 5, 7, 8, 1 in Table 1
0 is a solder composition (Example) within the scope of the present invention. Sample numbers 1, 3, 6, 9 and sample numbers 11, 12, 13, 14 marked with * are comparative examples outside the scope of the present invention, and among them, sample numbers 1, 3, 6, 9
Have the same composition as the solder composition of the present invention, and the compounding ratio is out of the range of the present invention. Sample numbers 11, 12, 13, and 14 are Bi or Cu among the components. Is not included. The sample number 11 is
This is a conventional Pb-Sn-based solder containing Pb.

Each of these samples (solder composition)
Was used to solder the enameled wire, and the Cu wire erosion and solderability were examined. In addition, regarding the Cu wire erosion property, an enamel-coated Cu wire having a diameter of 0.08 mm
The time elapsed until the Cu wire disappeared (Cu wire erosion time) was measured and evaluated when immersed in a solder bath at ℃. It is evaluated as highly effective.

Regarding the solderability, the wettability of the solder to a clean Cu plate at 400 ° C. was evaluated by the zero cross time in the meniscograph method. The shorter the zero cross time, the better the solder wettability. Note that an RMA type flux was used for soldering.

The results of the measurement (evaluation) of the Cu wire erosion and solderability are also shown in Table 1. As shown in Table 1, for Sample Nos. 1 and 6 that do not satisfy the condition of Equation (1), the melting point is 400 ° C. or more, and at normal soldering temperature, the solder does not melt, making measurement impossible. there were.

For sample No. 3, which does not satisfy the condition of equation (2), the Cu line erosion time was 10 seconds or less, and the Cu line erosion property (ie, the effect of suppressing Cu line erosion) was No satisfactory results were obtained.

Further, in sample No. 9, since the compounding ratio of Sn was smaller than the range of the present invention and the compounding ratio of Bi exceeded the range of the present invention, Cu line erosion (that is, Cu line erosion) was observed. ), A satisfactory result was obtained, but the zero cross time was as long as 1 second or more, and sufficient solder wettability could not be obtained.

On the other hand, for Sample Nos. 2, 4, 5, 7, and 8 in which Sn and Bi are within the scope of the present invention and satisfy the conditions of Formulas (1) and (2), the Cu wire The performance equivalent to that of the Sn-Pb-based solder conventionally used was obtained in both the erosion property and the solderability.

In addition, Sn-Bi- within the scope of the present invention.
For sample No. 10 in which Ag was added to the Cu-based solder composition, the performance equivalent to that of the Sn-Pb-based solder was obtained without impairing the Cu wire erosion or solderability.

Although not shown in Table 1, the Sn-Bi-Cu based solder composition within the scope of the present invention has
Even when one or more of n, Zn, Sb, Ge, and P are added, the performance equivalent to that of the Sn-Pb-based solder can be obtained without impairing the Cu wire erosion property and the solderability. Has been confirmed.

It should be noted that the present invention is not limited to the above embodiment, and various applications and modifications can be made within the scope of the invention.

[0030]

As described above, the solder composition of the present invention (Claim 1) contains Sn and Bi as main components, and further contains Cu at a predetermined ratio to contain no Pb. In addition, it is possible to obtain a solder which is excellent in safety and has the same properties as the conventional Sn-Pb-based solder in terms of solderability and Cu wire erosion.

Also, as in the solder composition of claim 2,
By blending Sn, Bi, and Cu in a further limited ratio than in claim 1, it is possible to reliably obtain a solder composition having excellent properties with respect to solderability and Cu wire erosion resistance. This makes it possible to make the present invention more effective.

Further, as in the third aspect of the present invention,
The solder composition of the present invention (claim 1 or 2) further includes at least one of Ag, In, Zn, Sb, Ge, and P.
By adding a seed, mechanical strength can be improved, the melting point of the solder can be controlled, the oxide film of the solder can be suppressed, and the properties can be further improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the compounding ratio of Cu and the compounding ratio of Cu in the solder composition of the present invention.

Claims (3)

[Claims] 1. A solder composition comprising Sn, Bi and Cu in the following proportions. Sn: 5.0 to 90.0% by weight Bi: 5.0 to 92.0% by weight Cu: 0.1% by weight or more and the following formulas (1) and (2)
(1) Cu addition amount (% by weight) ≧ (0.06 × Sn amount) −3.4 (Cu content (% by weight) ≦ (0.06 × Sn amount) −0.02) …… (2) 2. The solder composition according to claim 1, wherein Sn, Bi and Cu are blended in the following ratio. Sn: 14.8 to 42.0% by weight Bi: 57.0 to 85.0% by weight Cu: 0.1% by weight or more and the above formulas (1) and (2)
Range that meets the requirements of 3. The solder composition according to claim 1, further comprising at least one selected from the group consisting of Ag, In, Zn, Sb, Ge, and P. .