JPH06277870A - Extremely thin wall au-sn alloy brazing filler metal excellent in accuracy of thickness - Google Patents

Abstract

PURPOSE:To provide an Au-Sn alloy brazing filler metal which is extremely thin wall and excellent in accuracy of a thickness, to be used for joining electronic parts, etc. CONSTITUTION:An Au-Su alloy brazing filler metal having < 50mum thickness and whose accuracy of a thickness is <=+ or -10% of the thickness of a plate, is formed. Since such an Au-Sn alloy brazing filler metal is provided, in joining electronic parts, etc., whose quantity of use of a brazing filler metal is extremely small, the control of the quantity of its use is performed in a very small quantity unit, and the stabilization of a high quality at a joint part can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Au-Sn alloy brazing material used particularly for joining electronic parts.

[0002]

2. Description of the Related Art The plate thickness of a material used as a brazing filler metal is an important factor for controlling the amount of brazing filler metal used. If the amount of brazing filler metal used changes, the characteristics and shape of the product obtained will also change. Particularly in electronic parts, it is important to control the amount of brazing filler metal used because the performance of the joint is greatly related to the performance of the part and the size of the part is small. When using a foil-shaped brazing material, the amount used can be controlled by the area of the foil, but it is not possible to control only the area of the foil for electronic parts, etc. where the joints are very small. It is necessary to control it. However, the foil-shaped Au—Sn alloy brazing filler metal used for joining electronic components and the like so far is 50 μm at most even if it is thin.
In m, there was a limit to the thickness of the foil that can be provided. Therefore, when the amount of brazing filler metal used is very small, it is very difficult to control the amount.

The limitation on the plate thickness in the conventional Au-Sn alloy brazing material is derived from its manufacturing method. Up to now, the Au—Sn alloy brazing material has been manufactured by solidifying by the usual ingot casting method and then hot or warm rolling to form a foil. The Au-Sn alloy cannot be cold rolled because of its mechanical properties and must be hot or warm rolled, but there is a limit to the thickness of the foil obtained by hot rolling. The lower limit was 50 μm.

On the other hand, a thinner foil-like Au-Sn than before.
As a method for obtaining an alloy brazing material, for example, Japanese Patent Laid-Open No. 54-
In Japanese Patent No. 103764, a single roll method is used to obtain 50 μm.
It is stated that a foil-like Au—Sn alloy brazing filler metal having an overall amorphousness of m or less or an amorphous surface layer is obtained. However, in practice, the foil-shaped A is formed by the single roll method.
Although a u-Sn alloy is obtained, this foil-like alloy is very brittle and is not suitable for use as a brazing material. Moreover, such a foil has a poor plate thickness accuracy of, for example, ± 20% or more of the plate thickness, and is not suitable for use as a brazing material also from this point. This is because a foil having a poor plate thickness accuracy poses a problem from the viewpoint of controlling the intended amount of brazing material used. Further, in JP-A-55-103297, 63.5μ
It has been proposed to use a brazing filler metal having an amorphous structure in which at least 50% does not exceed m and is ductile. It is stated that such a thin brazing material can be obtained by quenching at a rate of at least 10 ⁵ ° C / s. However, such an as-cast foil still has poor foil thickness accuracy, and It is not preferable for use as a brazing filler metal in electronic parts and the like where the amount of material used is very small and the amount of material used is strictly controlled.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above problems in an Au—Sn alloy brazing material used as a brazing material for electronic parts, and has a plate thickness of less than 50 μm. It is an object of the present invention to provide an Au-Sn alloy brazing material having excellent thickness accuracy.

[0006]

To achieve the above object, the present invention has the following structures.
(1) The thickness is less than 50 μm, and the thickness accuracy is ± 10 of the thickness.
% Or less Au-Sn alloy, which is an ultrathin Au-Sn alloy brazing material excellent in plate thickness accuracy, and (2)
The plate thickness is less than 50 μm, the plate thickness accuracy is ± 10% or less, and the composition thereof has a Sn content of more than 4 wt% and 38 wt%.
An ultra-thin Au-Sn alloy brazing material having excellent plate thickness accuracy, characterized in that the balance is Au if less.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. In the present invention, if an Au--Sn alloy is rapidly solidified by a single roll method and further heat-treated under appropriate conditions, the ductility of the foil is developed and the foil is cold rolled. It is based on the new finding that an extremely thin Au-Sn alloy foil that can be obtained and has excellent plate thickness accuracy can be obtained. A method for obtaining an Au—Sn alloy brazing material having a plate thickness of less than 50 μm and a plate thickness accuracy of ± 10% or less of the plate thickness will be specifically described. The Au—Sn alloy is melted by, for example, high frequency induction melting, and is jetted onto a roll made of a metal having a high thermal conductivity such as copper to have a plate thickness of 100 μm.
The front and rear foil-shaped Au—Sn alloys are used. At this time, the roll is rotating at a high surface speed of, for example, 5 m / s or more.
The thickness of the obtained foil can be controlled by manufacturing factors such as the surface speed of the roll. In addition, suitable casting conditions for producing the Au—Sn alloy foil will be described in detail in Examples. Next, this foil is heat-treated under appropriate conditions. At this time, the optimum heat treatment conditions differ depending on the Sn content in the Au—Sn alloy, but the following conditions are preferable from the experimental results of the present inventors. That is, the processing temperature range is 100 ° C. or higher to a temperature just below the melting point. The processing time is in the range of a few minutes to a dozen hours, and the higher the processing temperature, the shorter the processing time. For example, when the Sn content is a eutectic composition of 20% by weight, the optimum heat treatment condition is that the treatment temperature is 120 ° C
The temperature is 260 ° C. and the treatment time is 5 minutes to 4 hours. This heat treatment develops the ductility of the foil and enables rolling even in the cold.
The optimum heat treatment conditions for various Au-Sn alloys will be specifically described in Examples. Finally, in order to improve the plate thickness accuracy of the foil, for example, ordinary cold rolling for ultra-thin steel is performed to obtain a foil having a predetermined plate thickness of less than 50 μm. At this time, a certain amount of reduction is required to improve the accuracy of the foil thickness, and the foil thickness obtained by casting with the single roll method should be around 100 μm, depending on the final target foil thickness. Is preferred. The numerical value used to define the range of the plate thickness accuracy of the foil of the present invention is shown by the ratio of the variation of the maximum and minimum plate thicknesses to the average plate thickness of the foil to the average plate thickness. For example, in the case of a foil having an average thickness of 40 μm and the variation of the thickness is within ± 4 μm, the thickness accuracy of this foil is ± 10.
Expressed as% or less.

In the production of the foil-shaped Au-Sn alloy brazing material by the single roll method, the Sn content is particularly 38 in view of the foil forming ability.
If it is less than weight%, it becomes easy. On the other hand, the Sn content is 4
If it is less than 10% by weight, the melting point becomes high, which is not preferable as a brazing material. Therefore, when the Sn content is more than 4% by weight and less than 38% by weight, it is more effective to provide the brazing material for such an ultrathin foil.

According to the present invention, since it is possible to provide an Au-Sn alloy brazing material having a plate thickness of less than 50 μm and good plate thickness accuracy, it is possible to control the amount of the brazing material used in joining electronic parts and the like. It has become easier, and it has become possible to suppress variations in product characteristics and shapes that have occurred up to now due to variations in the amount of brazing material used for brazing. In addition, it became possible to suppress the occurrence of troubles due to excessive brazing material.

[0010]

EXAMPLE 200 g of Au—Sn alloy having various Sn contents as shown in Table 1 was used to obtain a plate width of 6 by the single roll method.
Foil having various plate thicknesses in mm was prepared. The roll of the single roll machine was made of copper and had a diameter of 300 mm. During casting, the ejection pressure was 0.2 kg / cm ² and the casting atmosphere was helium gas. Next, the obtained foil was heat-treated under appropriate conditions. The heat treatment conditions are shown in Table 1.
The Au—Sn alloy foil thus prepared was rolled one to several times under various loads using a pair of rolls having a diameter of 60 mm. The thickness and accuracy of the thickness of the foil thus obtained were investigated. The results are shown in Table 1.

[0011]

[Table 1]

As shown in Table 1, an Au-Sn alloy brazing material having a plate thickness of less than 50 μm and having a target thickness and having a plate thickness accuracy of ± 10% or less was obtained. Such Au
The Sn alloy brazing material makes it possible to control the amount of brazing used even when the amount of brazing used is very small, and was extremely suitable for joining electronic components and the like.

[0013]

INDUSTRIAL APPLICABILITY As described above, the Au-Sn alloy brazing filler metal of the present invention enables control of the amount of use to a minute unit as compared with the conventional Au-Sn alloy brazing filler metal. In the bonding of electronic components and the like in which the usage amount of is very small, the quality of the electronic components is improved, the quality is made uniform, and the manufacturing yield is significantly improved.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shin Tanaka, No. 1 Tobahata-cho, Tobata-ku, Kitakyushu, Fukuoka Prefecture (72) Inside the Yawata Works, Nippon Steel Corporation (72) Toshihiro Hanamura Nakahara-ku, Kawasaki-shi, Kanagawa 1618 Ida, Nippon Steel Corporation Advanced Technology Research Laboratories (72) Inventor, Yoichi Ikematsu 1618 Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Nippon Steel Corporation Advanced Technology Research Laboratories

Claims (2)

[Claims] 1. An ultra-thin Au-Sn alloy brazing material having an excellent plate thickness accuracy, which is an Au-Sn alloy having a plate thickness of less than 50 μm and a plate thickness accuracy of ± 10% or less of the plate thickness. 2. The plate thickness is less than 50 μm and the plate thickness accuracy is ± 1.
0% or less, and its composition has a Sn content of 4% by weight.
An ultra-thin Au-Sn alloy brazing material excellent in plate thickness accuracy, characterized in that the balance is Au at less than 38% by weight.