JPS5865595A - Partially soldered clad material and its production - Google Patents

Abstract

PURPOSE:To obtain a partially soldered clad material which is stuck with solder only in the required places by cladding solder of a specified areas at specified intervals on a high m.p. metallic belt-like body. CONSTITUTION:Recesses 3 are inscribed at specified intervals on a high m.p. metallic belt-like body, for example, a Cu belt-like body 1. Solder 2 is installed in the recesses 3, and the same is rolled with rolls R, whereby the solder 2 and the material 1 are clad. Since the clad material has a specified solder stuck area and does not use any flux, there is no effect of the flux, and the clad material is ideally suited as an electronic parts material.

Description

[Detailed Description of the Invention] The present invention relates to a partial solder clad material in which solder is attached only to necessary locations, and a method for manufacturing the same.Recently, materials in which solder is attached to high-melting point metals are used in electronic components. There are more things to do.

For example, in power transistors, a small element is connected to a nickel heat sink using solder, and in IC die bonding, a copper lead frame and an IC element are connected using solder.

Conventionally, heat sinks and lead frames have been used by punching into a predetermined shape from a high-melting point metal strip material that is fully plated or partially pre-plated.

However, if the entire surface is plated, expensive solder will adhere to the non-soldered parts where the elements are not mounted, which is not only uneconomical, but also makes it difficult to process the parts into a predetermined shape using processing equipment such as a press.
Solder builds up on the edges of the press, resulting in poor machining and finishing conditions, and in some cases, the edges of the press may be damaged due to unreasonable machining.

In addition, conventional partially solder-plated products are made by applying cream solder at regular intervals to a high-melting point metal strip and heating it, or by placing solder pieces and flux and heating them. However, since all solder-plated materials in this area are attached by melting solder, the solder spread area is not uniform, making it unsuitable for electronic components. In other words, if the molten solder plated part is smaller than the power transistor element or IC element, the soldering will be defective, and if it is too large, unnecessary solder will invade the element and cause a defect. It can become a cause.

Furthermore, since conventional partial solder plating materials use 7 lux in the manufacturing process, care must be taken to remove flux residues that may adversely affect electronic components. There is also a method of placing a solder piece on a high-melting point metal strip and performing partial solder plating in a reducing atmosphere without using 7lux, but this method not only requires a large amount of cost for the heating equipment and reducing gas for the reducing atmosphere, but also In a reducing atmosphere, excellent soldering cannot be expected when flux is used, and many solderings are defective due to insufficient solder spreading area, which is not practical.

The present invention provides an electro-crystalline partial solder cladding material in which a certain area of solder adheres to a desired location on a high-melting point metal strip material, and there is no problem of flux residue, and a method for manufacturing the same. It's true.

First, the partial solder clad material of the present invention will be explained.

As shown in Fig. 1, the partial solder cladding material of the present invention consists of a high melting point metal strip (1) and a certain area of solder (2) at regular intervals.
is clad. As can be seen in FIG. 2, which is a sectional view taken along the line 1-1 in FIG. 1, the high melting point metal strip (1) and the solder (2) are in an inlay state.

Therefore, when the partial solder cladding material of the present invention is used in the above-mentioned electronic components, since the solder cladding part has a constant area, soldering due to insufficient solder adhesion area when bonding transistors and IC elements may be defective or excessive soldering may occur. It never invades the device and deteriorates the characteristics of electronic components.

Further, even when the clad material of the present invention is punched, there is no solder attached to the entire high melting point metal strip material, so there is no risk of damaging processing equipment such as a press, and furthermore, this is unnecessary. It also represents the economic advantage of no solder adhesion.

K to obtain a partial solder clad material having excellent features as mentioned above is simply a high melting point metal strip material (1
) can also be obtained by placing solder (solder) on top of the solder and rolling it. However, with this method, the solder cladding may not be formed at the specified location, or the cladding material may be deformed and used for electronic components. However, with this method, when the solder is rolled and meshes with the four wheels of the rolling mill, the solder slips and is blown off, making it impossible to keep it in place easily. The position of the cladding part shifts.Also, the reason why the cladding material is deformed is because the overall thickness of the part of the high melting point metal strip where the solder is placed becomes thicker, so the reduction ratio of that part increases. This is because the impact is larger than other parts, and the effect extends to the periphery of the cladding, creating a rippling condition.

A product in which the position of the cladding portion is shifted or deformed in this manner cannot be used in today's electronic components that require precise dimensional accuracy.

The present inventors have invented a manufacturing method for partially soldered clad material that not only allows the solder cladding portion to be in a predetermined position but also prevents the cladding material from changing, and so we are disclosing that technology here. be.

The manufacturing method of the present invention will be explained below based on the drawings.

FIGS. 4(A) to 4(C) are diagrams illustrating the steps of the method for manufacturing a partial solder clad material according to the present invention.

Step (A): Recesses (3) are carved at regular intervals on the high melting point metal strip (1) K.

Step (B): Place solder (solder) in the recesses carved in (A).

Step (C): The high melting point metal strip with solder placed in the recess is rolled using a roll, and the solder and the high melting point metal strip are clad.

The size of the recess carved in the above step and the solder placed therein are determined in consideration of the elongation in the rolling direction due to rolling 1. That is, since the metal strip material stretches significantly in the rolling direction, the recess must be narrow in width in the rolling direction as well as the desired solder cladding.
Since the degree of elongation due to rolling changes depending on the material, rolling reduction rate, etc., the indentation to be carved in the process (shu) is determined empirically.

The solder (2) to be placed in the recess in step ) has approximately the same shape as the recess 1.

Next, embodiments of the present invention will be described.

Example: 5 stripes at 3m intervals on a copper strip material with a thickness of III+1 and a width of 20m+.
Carve a depression of ■×1■×0.3■. Next, a solder piece (60Sn-pb
) and roll it with a roll to a thickness of 0.2 cm.

The partial solder clad material obtained in the example had a thickness of 0.2 m.
% A strip of material with a width of about 20 txm was used, and the clad solder part had a size of about 5 cm x about 5 cm. When the pieces were punched into ×81 pieces using a press and soldered to an element as a lead frame for an IC, there were no soldering defects or any deterioration of the characteristics of the IC.

As explained above, the partial solder clad material of the present invention is most suitable as an electronic component material because the solder adhesion area is constant and since 7 lux is not used, there is no effect of slack residue. Further, since the manufacturing method according to the present invention can produce a cladding material without causing deformation due to strain in the cladding material, it is possible to supply materials for electronic components that require extremely strict dimensional accuracy.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the partial solder clad material of the present invention, Fig. 2 is a sectional view taken along the line 1-is in Fig. 1, Fig. 3 is a comparative example of a method for manufacturing the partial solder clad material, and Fig. 4 is a manufacturing method of the present invention. It is a figure explaining the process of a method. 1... High melting point metal strip material 2. Z...Solder 3...
・Dent R...Roll 1st w4 2nd g 3rd W4

Claims (2)

[Claims] (1) A partial solder clad material characterized in that a high melting point metal strip is clad with a certain area of solder at regular intervals. (2) Make depressions at regular intervals in a high melting point metal strip, place solder pieces in the depressions, and then roll the high melting point metal strip to a certain area at regular intervals. A method for producing a partial solder clad material, characterized by cladding with solder.