JPS59153857A - Alloy for forming joint - Google Patents

Abstract

PURPOSE:To obtain an alloy for forming a joint having superior mechanical strength, thermal strength and wetting properties by preparing an alloy consisting of specified percentages of Sn, Sb, Bi, P, Ga and Pb. CONSTITUTION:An alloy consisting of, by weight, 5-90% Sn, 1-15% Sb, 0.1- 15% Bi, 0.00001-0.5% P and/or Ga and the balance Pb is prepd. <=3% Ag may be further added to the alloy. The alloy has superior physical properties and work efficiency, and it can be properly used to join parts of a small-sized electronic machine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alloy for forming a joint which has excellent mechanical strength, thermal strength and wettability.

In general, Sn-Pb alloys are widely used as alloys for forming joints in devices, parts, etc., and when a silver film is present in the joint, Ag melts into Sn.
Sn-Pb-Ag alloys are used for the purpose of preventing r1 diffusion. However, in recent years, there has been a significant demand for the miniaturization of electronic devices, and as a result, miniaturization of components and higher density design have become inevitable. In order to respond to such changes in the field, it is also inevitable that alloys for forming joints are required that can improve the strength of the joints even under low joint areas (4).

Conventionally, the addition of sb has been considered to improve the strength of 5n-Pb and 8n-Pb-Ag alloys, but although the addition of Sb can improve sheet mechanical strength and thermal strength,
Since the addition of sb is limited by the amount of Sn in the alloy, the melting temperature of the alloy is restricted, and the addition of sb reduces the wettability of the joint, which has a negative impact on physical properties and workability. This has led to negative results.

The purpose of the present invention is to improve these conventional drawbacks and provide an alloy for forming joints that not only has mechanical strength and thermal strength of the joint, but also has good wettability and easy control of melting temperature. That is.

That is, in the present invention, Sn: 5-90.

sb: 1 to 15% by weight, Bt: o, x to 15% by weight
blood.

P and Ga 1 god or z persimmon: o, oooo1~'
5. Consisting of an alloy with the remainder being PB, or an alloy further containing Ag: 3 or less. According to the alloy of the present invention, 't7 is improved by adding Bi while controlling the melting temperature caused by sb added for the purpose of improving mechanical strength and thermal strength. 11D17 Wetness is improved by adding two glazes over each other, thereby eliminating the drawbacks of conventional alloys for forming high-strength joints.

Furthermore, according to the present invention, by changing the effect of the additive elements 111 and changing the strength t of each additive element within a predetermined range, the effect can be adjusted according to the user's preference. Alloys are provided.

In the present invention, the reasons for limiting the composition of each component are as follows.

If the Sn-containing phase is less than 5, the melting point of the alloy itself will be extremely high, which will not only cause various problems due to the high working temperature, but also cause the diffusion of metal into the metal at the joint. Sufficient junction RI because the factor is less than 171f/
S formation becomes impossible. On the other hand, the content% of Sn is 90πe
If it exceeds 'F=, H%, the cost of the alloy will increase, and furthermore, if AgyAuLiA etc. are present in the mother interest IA jTli, there will be adverse effects such as promoting dissolution and diffusion into the joining alloy (1!11). Therefore, Sn
The content is in the range of 5 to 90 v%, preferably 20 to 60 v%.

If the sb content is less than 1 ply, the shrinkage rate is recommended.
Although some effects such as improvement in creep strength can be seen, sufficient effects cannot be obtained regarding the main strength improvement.On the other hand, S
An increase in the content of b has the property of reducing wettability, and furthermore, if it exceeds the percentage of the Sn content, it will have a large impact on the entire alloy, so the effect of adding P and/or 1dGa will be reduced. Even if this is taken into account, the upper limit is assumed to be 15 cars,
Preferably, it is in the range of 1 to 10 cars.

Bi is added to adjust the melting point, and its content is 0.19%. , 'J', t, has almost no effect if it is less than %. On the other hand, if the content of old is too large, disadvantages such as the alloy becoming brittle will occur, so the upper limit is 1li.
It will be 15 times.

Ag is to be included when an Ag bladder is present in the joint.9) If it is to be used publicly, the angle should be 3° or less from the viewpoint of economy.

P and Ga aim to improve wettability by utilizing the inherent activities of these elements, and their effect is exhibited from 1% or 2 of these P and Ga contents of 0.00'001 weight cake. However, if it is contained in a large amount, it has the effect of drastically changing the properties of the alloy such as repellency and roughness, so the upper limit is set at 0.5% by weight and 4%.

The alloy obtained in this way increases mechanical and thermal strength due to the effect of sb, improves synergism due to the effects of P and Ga, and further diversifies the melting temperature through proper use of the alloy. It has excellent strength, physical properties, and workability, and is suitable for use in joining recently miniaturized electronic devices and parts.

Examples are shown below.

Example Conventional Sn-Pb having the composition shown in the table below.

The physical properties of the Sn-Pb-Ag alloy and the alloy of the present invention were compared. Record the results in the milk.

In addition, the temperature in parentheses () in the Jitsuji-Kobako box is 140℃.

Figures are shown after 240 hr aging. In addition, the wettability and wideness rate is determined by using one button plate of 0.3 x 30 x 30 mm, making the 35% ww solution 7 lac, and melting point + 5.
It was carried out at a temperature of 0°C.

(Margin below)

Claims (1)

[Claims] 1, 8n: 5 to 901 gH%, Sb: 1 to 15 weight it
%. Bl: 0.1 to 1 swt%, one or both of P and Ga: 0.00001 to 0.5wt%, IA part p
A joint forming alloy consisting of b. 2, Sn: 5-90@M3, Sb: 1
~15 weight molecules. BI: 0.1 to 15% by weight rAg: 3% by weight or less. P and Ga 1 type 1 Dani 2 rods: 0.00001 to 0,
An alloy for forming joints consisting of 5% by weight and the remainder PB.