JPH083787A - Filamentary body for saw wire and its production - Google Patents

Abstract

PURPOSE:To produce a filamentary body for a saw wire having a finer diameter used for cutting without deteriorating its toughness by forming a film constituted of copper or a copper allay contg. a specified ratio or above of copper with specified thickness on the surface of a steel filamentary body. CONSTITUTION:On the surface of a steel filamentary body, a film constituted of copper or a copper alloy contg. >=75wt.% copper with 0.04 to 0.50mum thickness is formed. As this copper alloy, brass can be selected. This steel filamentary body is subjected to cold wire drawing in the range of 3.1 to 4.8 true strain to form into a filamentary body for a saw wire. For example, the surface of a high carbon steel wire having 0.50 to 1.70mm wire diameter is plated with copper or a copper allay contg. >=75wt.%. copper of 0.2 to 4.0mum thickness, which is thereafter worked to 0.05 to 0.35mm wire diameter by cold wire drawing to form into a filamentary body for a saw wire. Thus, its wire drawability is improved to increase its working limit, by which the filamentary body for a saw wire having a finer diameter can be obtd. without deteriorating its toughness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a saw wire used for cutting semiconductor members such as silicon wafers, metals, ceramics, stones, etc., and a method for manufacturing the saw wires.

[0002]

2. Description of the Related Art Conventionally, as this kind of wire, a high carbon steel wire is drawn, and a high carbon steel wire is made of Cu60 to 70% by weight and Zn.
It is known that brass plating of 30 to 40% by weight is performed and wire drawing is performed.

Then, they are used for cutting by attaching them to a wire saw, or by applying a liquid containing diamond abrasive grains to the work part. Separately, as disclosed in, for example, JP-A-54-21692, it has been proposed to use abrasive grains fixed to the outer surface of the wire in advance as a saw wire.

Japanese Unexamined Patent Publication (Kokai) No. 5-20067 is a proposal regarding the steel composition, heat treatment conditions, and the like in a small-diameter saw wire.

[0005]

Generally, saw wires are used for cutting high value-added materials such as semiconductor members, metals and ceramics, and the size of the wire diameter is the size of the cutting debris generated during cutting. Therefore, in order to improve the yield, it is necessary to reduce the diameter of the saw wire. Even if the diameter is reduced,
At the time of use, in order to improve the cutting accuracy, an appropriate tension is applied in the longitudinal direction of the wire for use. Therefore, high strength is required to withstand this tension.

However, since the above-mentioned conventional saw wire is manufactured from a high carbon steel wire itself having extremely poor wire drawability, as the wire drawability is increased and the wire is made finer, the toughness decreases due to wire breakage or work hardening. Therefore, there is a problem that the yield in the manufacturing process deteriorates.

The high carbon steel wire with brass plating on its surface has better wire drawing workability than the one without brass plating, but with brass plating having a Cu ratio of 60 to 70% by weight, the plating composition is Due to the non-uniformity, β-brass with poor ductility tends to remain in a part of the plating, and in the processing where the true strain exceeds 4.1, the toughness decreases due to work hardening and the processing limit is low.

[0008]

The present invention has been made to solve the above-mentioned problems, and the first feature thereof is that a copper wire having a thickness of 0.04 to 0.50 μm is formed on the surface of a steel filament. And / or forming a coating film made of a copper alloy containing 75% by weight or more of copper.

The second characteristic is that brass is selected as the copper alloy. And the third feature is
The steel wire on which a coating film of copper and / or a copper alloy is formed is subjected to cold wire drawing in the range of true strain of 3.1 to 4.8 to obtain a wire for saw wire.

The fourth feature is that, as the most preferable method for producing the saw wire, the steel wire strip, the plating and the wire drawing conditions are specified respectively, the contents of which will be shown by examples.

[0011]

[Example] For a C0.78 wt% high carbon steel wire having a wire diameter of 0.7 mm,
Copper plating having a thickness of 0.73 to 0.79 μm (Example 1), brass plating having 80% by weight of Cu (Example 2), and brass plating having 70% by weight of Cu (Comparative Example 1) were applied by electroplating, respectively, and cold-rolled. Wire processing was performed and the wire diameter was dropped to 0.08 mm. At this time, the plating thickness was reduced to 0.08 to 0.09 μm.

Separately, a C0.78 wt% high carbon steel wire with a wire diameter of 1.0 mm is copper-plated with a thickness of 30 μm (conventional example 1) and 8.8 μm.
(Example 3), 0.1 μm (conventional example 2), respectively, were electroplated and cold drawn to obtain a wire diameter of 0.16 mm.
I withdrew. The plating thickness at this time is
4.8 μm, Example 3 decreased to 0.14 μm, and Conventional Example 2 decreased to 0.02 μm.

(Test Results) Tensile strength and twist value were measured for the wires of the above Examples, Comparative Examples and Conventional Examples. The results are shown in Tables 1 and 2.

[0014]

[Table 1]

[0015]

[Table 2]

As can be seen from Table 1, in Examples 1 and 2 in which the copper ratio was higher than in Comparative Example 1, the twist value was higher even with the same workability, and the workability limit was increased by improving the wire drawability. Shows. In addition, Examples 1 and 2 show that 100% copper is superior.

Next, a comparison of characteristic values according to the plating thickness in Table 2 is made. Conventional Example 2 has a smaller plating thickness than Example 3, so that the wire drawing workability is deteriorated. It has the same degree of processing as the others, but the tensile strength is low. This is because the ratio of the plating thickness to the wire diameter is larger than that of the others.

[0018]

In the filament wire for saw wire of the present invention, the surface of the steel wire is plated with copper and / or a copper alloy containing 75% by weight or more of copper. Workability is improved.

Particularly, this plating thickness is 0.2 to 4.0 μm in a high carbon steel wire having a wire diameter of 0.50 to 1.7 mm, and a true strain of 3.1 to
Wire drawing in the range of 4.8 gives the best wire drawing workability and strength improvement by processing, and the wire drawn to a wire diameter of 0.05 to 0.35 mm has a high strength enough to withstand tension when used as a saw wire. Had.

[0020]

As described in the above paragraphs, according to the present invention, the wire drawing workability is improved, so that the workability limit is increased and the toughness of the wire body for a saw wire having a smaller diameter is not increased. Obtainable. As a result, it is possible to efficiently cut semiconductor members, ceramics, metals and the like, which have high added value, with a small amount of cutting waste.

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Claims (4)

[Claims] 1. A thickness of 0.04 to 0.50 μm on the surface of the steel filament.
And a copper alloy containing at least 75% by weight of copper. 2. The filamentous body according to claim 1, wherein the copper alloy is brass. 3. The method according to claim 1 or 2, wherein after forming a coating film of copper and / or a copper alloy on the steel filament, cold drawing is performed within a true strain of 3.1 to 4.8. Striatum. 4. The surface of a high carbon steel wire having a wire diameter of 0.50 to 1.70 mm is provided with copper and / or a copper alloy containing 75% by weight or more of copper.
A method for manufacturing a filament for a saw wire, which comprises forming a wire having a diameter of 0.05 to 0.35 mm by cold drawing after plating to a thickness of 0.2 to 4.0 μm.