TWI594838B - Wave-patterned monowire for cutting and a method of manufacturing the same - Google Patents

Description

Corrugated monofilament type steel wire for cutting and manufacturing method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a corrugated monofilament type wire for cutting, and more particularly to a corrugated monofilament type wire for cutting a semiconductor ingot, ceramic, glass or the like which is similar to a hard material, which is capable of improving a cut workpiece. Surface Quality.

A wafer made of 矽 (for solar cell substrates, etc.), quartz (for various industrial fields such as automobiles), gallium arsenide (for high-frequency electronic products), etc., is a cylindrical ingot ( Ingot) formed after cutting into a thin plate shape. The cutting mechanism of the ingot is to cut a workpiece by using a wire and an abrasive. At this time, as a conventional steel wire, a brass monofilament type steel wire is used, which functions as an abrasive carrier, and recently, a wire surface has been developed to improve the cutting ability to enhance the carrier capacity of the abrasive (carrier capability). )The product.

The general linear steel wire has the disadvantage that the cutting speed of the ingot is low because of the poor carrier performance of the abrasive; and the problem is that the diameter of the steel wire is gradually reduced because the steel wire is worn during the process. Small, the carrier capacity and cutting efficiency of the abrasive are gradually reduced.

Korean Patent No. 888,026 discloses a saw wire having a diameter ranging from 0.08 to 0.30 millimeters (mm), a residual stress of the saw wire in the longitudinal direction, and an area ranging from 5 to 10 μm in depth from the surface of the saw wire. It is 400~1000 MPa (MPa). In the cutting process, the cutting performance is degraded due to the reduced diameter of the cutting line. This patent discloses a linear line having a specific range of residual stress to convert the linear shape into a small corrugated shape for Compensates for degraded cutting performance. However, the problem with this linear line is that the surface quality of the cut workpiece is considerably deteriorated because it is difficult to precisely control the residual stress of the linear line.

Japanese Unexamined Patent Publication No. 2012-121101 discloses a fixed abrasive granule in which an abrasive is fixed to the surface of the wire. The fixed abrasive grain line is a corrugated line in which a plurality of corrugated curved portions are continuously arranged within each pitch based on the diameter of the line in the longitudinal direction. The fixed abrasive grain is characterized in that the corrugated curved portions have a spiral-shaped wave-patterned. A problem with the fixed abrasive wire is that it is difficult to maintain the shape of the corrugation during cutting, so the efficiency of the cutting process is reduced, and the flatness of the surface of the cut workpiece is deteriorated due to the uneven thickness of the cut workpiece.

It is an object of at least one embodiment of the present invention to provide a corrugated monofilament type wire for cutting having desired properties of an abrasive carrier and desired ingot cutting performance for improvement Ingot cutting speed and surface quality of the cut workpiece.

According to an exemplary aspect of the present invention, a corrugated monofilament type wire for cutting includes a single metal wire, wherein the wire is formed to include a plurality of corrugations having a predetermined period and formed in the longitudinal direction. One or more planes, the height H of the corrugation divided by the value of the period P of the corrugation H/P, in the range of 3 to 12%, each plane containing an axis, and when from the center of a corrugated monofilament type wire The axes are staggered from each other at an angle of 45 to 135 degrees when viewed from the axis.

In a three-dimensional (3D) coordinate system in which corrugations are formed, the corrugated monofilament type steel wire is configured to rotate on a single axis, and the single axis is different from the plurality of axes forming the corrugated 2D plane, so that the effect can be achieved, The number of planes imparted with corrugations is greater than the number of planes actually formed with corrugations.

According to another aspect of the present invention, a method of manufacturing a corrugated monofilament type wire for cutting includes the following steps. Feeding a monofilament type wire through a feeding unit, a plurality of corrugations are imparted to the monofilament type wire by a first corrugating device, the first corrugating device comprising a pair of gears having a corrugated depression on a surface thereof And bulge and rotate in the opposite direction. Before the monofilament type steel wire is fed to a second corrugation imparting device, the first corrugated wire is wound around the first corrugated wire feeding device 0.5 to 3 times, and the first corrugated device is passed The monofilament type wire which is imparted with corrugation is twisted in a clockwise or counterclockwise direction. By the second corrugation applying device, a plurality of other corrugations are imparted to the monofilament-shaped wire through which the corrugations have been formed by the first corrugating device, and the second corrugating device is supported relative to the first One The corrugation imparting means has an angle in the range of 45 to 135 degrees. And by winding the monofilament-type steel wire around the second corrugation-imparting device 0.5 to 3 times, the monofilament-shaped steel wire to which the other corrugation has been applied by the second corrugation-imparting device Torque in a clockwise or counterclockwise direction.

10‧‧‧Mono wire

20‧‧‧First corrugated device

30‧‧‧Second corrugated device

The above and other objects, features and advantages of the present invention will become more <RTIgt;

Fig. 1 is a schematic perspective view showing a conventional saw wire.

Fig. 2 is a schematic side view showing a corrugated monofilament type wire for cutting according to an embodiment of the present invention.

Fig. 3 is a view showing the structure of a corrugation when viewed from a central axis of a corrugated monofilament type wire for cutting according to an embodiment of the present invention.

Fig. 4 is a schematic view showing a corrugating device for manufacturing a corrugated monofilament type wire for cutting according to an embodiment of the present invention.

Fig. 5 is a schematic view showing a corrugating device for manufacturing a corrugated monofilament type wire for cutting according to an embodiment of the present invention.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, well-known functions and structures that are considered to be unnecessarily obscured by the gist of the present invention will be omitted.

A corrugated monofilament type wire for cutting according to an embodiment of the present invention includes a single metal wire, wherein the wire is formed to include a plurality of wavy-patterned waves having a predetermined period and formed in a longitudinal direction Two or more planes, the height H of the corrugation divided by the value of the period P of the corrugation H/P, in the range of 3 to 12%, each plane containing one axis, and when from a corrugated monofilament type wire When viewed from the center axis, the axes are staggered from each other at an angle of 45 to 135 degrees.

Fig. 2 is a schematic side view showing a corrugated monofilament type wire 10 for cutting according to an embodiment of the present invention. Fig. 3 is a view showing the structure of a corrugation when viewed from the central axis of the corrugated monofilament type wire 10 for cutting according to an embodiment of the present invention. 2 and 3, according to the corrugated monofilament type wire for cutting according to the embodiment, two or more corrugations formed in different planes are disposed in the radial direction around the central axis. According to the present embodiment, the shape of the corrugation is not limited to a specific shape, but may have, for example, a sawtooth shape or a sine wave shape.

In a three-dimensional (3D) coordinate system in which corrugations are formed, the corrugated monofilament type steel wire is configured to rotate on a single axis, and the single axis is different from the plurality of axes in which the corrugated 2D plane is formed, so the effect achieved by the embodiment To be, the number of planes that are imparted with ripples is greater than the number of planes that actually form ripples.

In the corrugated monofilament type wire for cutting according to the present embodiment, the ratio H/P, that is, the ratio of the height H of the corrugation to the period P of the corrugation, is in the range of 3% to 12%, preferably between It is in the range of 3 to 11% and is therefore suitable for improving the carrier properties of the abrasive in the cutting process. In this case, when the value H/P is less than 3%, the carrier properties of the abrasive are insufficient, so that scratches are generated. On the other hand, when the value H/P exceeds At 12%, the carrier properties of the abrasive were too large, resulting in a difference in wafer thickness.

Further, referring to Fig. 5, each of the planes includes a shaft, and the shafts are staggered from each other at an angle of 45 to 135 degrees when viewed from a central axis of a corrugated monofilament type wire. An angle between a first corrugation and a second corrugation formed on two or more different planes, ranging from 45 degrees to 135 degrees. When the angle is less than 45 degrees, the uneven residual stress remains in the material of the monofilament type steel wire itself, and thus the degree of linearity is deteriorated to deteriorate the cutting performance. On the other hand, when the angle exceeds 135 degrees, the residual stress is lowered after the cutting, and thus the stability of the corrugated shape is deteriorated, which causes a problem that the reduction in the cutting performance is accelerated with time.

In the present embodiment, the ratio Hc/Hi between the height Hc after cutting of the corrugated monofilament type wire for cutting and the height Hi before cutting is in the range of 0.80 to 0.95%. When the value of Hc/Hi is less than the lower limit, a saw mark may be generated. On the other hand, when the value of Hc/Hi exceeds an upper limit value, a total thickness variation (TTV) may be generated.

The corrugated monofilament type wire 10 for cutting according to the embodiment has a structure in which a metal plating layer is plated on the surface of the metal wire to improve the adhesion of the abrasive, for example, including high carbon steel. It is made of steel of tungsten and copper, and the metal plating layer is made of a metal such as copper or brass.

The elongation of the monofilament type steel wire at the breaking point is in the range of 2.0% to 3.5%, and is in the range of 10 to 40N. In this embodiment, when the elongation of the corrugated monofilament type steel wire at the breaking point is less than 2.0%, It is impossible to ensure the minimum flexibility required for cutting a corrugated monofilament type wire, and thus the processing efficiency may be reduced. On the other hand, when the elongation of the corrugated monofilament type steel wire at the breaking point is more than 3.5%, the carrier properties of the abrasive are insufficient, and thus the surface quality and processing efficiency of the cut workpiece may be reduced.

In the corrugated monofilament type wire for cutting of the present embodiment, the diameter d of the monofilament type wire is preferably in the range of 0.03 to 0.5 mm. When the diameter d of the monofilament type steel wire is less than 0.03 mm, the strength required for the cutting line cannot be obtained. On the other hand, when the diameter d of the monofilament type steel wire exceeds 0.5 mm, the kerfloss may increase. One factor in controlling the yield rate when cutting a workpiece using a cutting line is the kerf loss. When the cutting line is digging into a workpiece such as an ingot, a cutaway groove is generated, and the slit loss refers to the width of the slit. The loss of the cut is inversely proportional to the yield. In order to minimize the loss of the cut, it is necessary to reduce the diameter of the cut line, so the cut line must be very thin or ultra-thinned. To achieve this, there is a need for an ultra high strength monofilament type steel wire which has high cutting strength and exhibits high toughness. In the present embodiment, in order to reduce the loss of the workpiece and increase the cutting speed at the time of cutting, a corrugated monofilament type steel wire for thin cutting having a diameter of 0.5 mm or less is provided.

In the corrugated monofilament type steel wire for cutting according to the present embodiment, the diameter d of the corrugated monofilament type steel wire, the height H of the corrugation wire, and the period P of the corrugation satisfy the following conditions: P = 1-10 mm, d = 0.03 - 0.5mm and 1.2×d mm h mm 3.0 × d mm.

In the present embodiment, when the height H of the corrugation is lower than the diameter d of the monofilament type steel wire, the distance between the workpiece to be cut and the abrasive cannot be sufficiently ensured, and thus the carrier properties of the abrasive may be deteriorated. On the other hand, when the height H of the corrugation is higher than the diameter d of the monofilament type steel wire, it is difficult to impart a corrugation on a single surface on which the corrugation is to be formed, and thus there is a fear that the precision of the machined surface may be lowered.

The corrugated monofilament type wire 10 for cutting according to this embodiment has a carbon content ranging from about 0.7 to 1.2% by weight. The ratio of the copper component of the brass-plating layer is preferably in the range of 60 to 80%. When necessary, a third element such as zinc, tin, nickel, cobalt, chromium, and an alloy of the metals can be added to the copper plating layer in an amount ranging from 0.1 to 6.0%. Alloy coatings improve corrosion resistance and strength.

The coating layer of the corrugated monofilament type steel wire for cutting according to the embodiment can further comprise a plurality of abrasive grains, the abrasive particles being composed of a group selected from the group consisting of diamond, tantalum carbide, tungsten carbide, and the like. One of the groups is composed.

The tensile strength of the corrugated monofilament type steel wire for cutting according to this embodiment is in the range of 300 to 600 kg/mm ² . In order to achieve the intrinsic purpose of the corrugated monofilament type wire for cutting, that is, cutting and slicing of a hard material such as a semiconductor, ceramic or hard metal, sufficient cutting force is required, so the cutting according to the embodiment The reason why the strength of the corrugated monofilament type steel wire is limited to the range of 300 to 600 kg/mm ² is to secure the aforementioned cutting force. Further, in order to obtain the strength required for the ultra-thin corrugated monofilament type steel wire, a method of performing a drawing process at a high processing level equal to or higher than 90% may be employed. When necessary, an alloying element such as chrome or vanadium is added to the original material to increase the strength.

The corrugated monofilament type wire for cutting according to the present embodiment cuts the workpiece in such a manner as to move together with the cutting fluid and at a suitable pressure to contact the workpiece, wherein the abrasive is combined with a lubricant such as oil or the like Mixed in the cutting fluid. A method of forming a wafer by cutting a hard material such as a workpiece to be cut according to the corrugated monofilament type wire for cutting according to the present embodiment will be described in detail below. A continuous row of corrugated monofilament type wire is wound around a plurality of rolls having a plurality of grooves at a predetermined pitch, and then moving a continuous row of corrugated monofilament type wires for cutting. The workpiece to be cut is pressed against the continuous row of corrugated monofilament type wires by a predetermined force. At this time, the cutting fluid is introduced between the cutting corrugated monofilament type wire of the row and the workpiece to be cut. Therefore, the workpiece can be cut to form a wafer by the cutting action of the abrasive particles.

According to an aspect of the invention, a method of manufacturing a corrugated monofilament type wire for cutting is provided. The method for producing the above-described corrugated monofilament type wire for cutting includes the following steps. Feeding a monofilament type wire through a feeding unit, a plurality of corrugations are imparted to the monofilament type wire by a first corrugating device, the first corrugating device comprising a pair of gears having a corrugated depression on a surface thereof And bulge and rotate in the opposite direction. Before the monofilament type steel wire is fed to a second corrugation imparting device, the first corrugated wire is wound around the first corrugated wire feeding device 0.5 to 3 times, and the first corrugated device is passed And the monofilament type wire which is imparted with corrugation is clockwise or reverse Torque in the hour hand direction. By the second corrugation applying device, a plurality of other corrugations are imparted to the monofilament-shaped wire through which the corrugations have been formed by the first corrugating device, and the second corrugating device is supported relative to the first A corrugated device is at an angle of 45 to 135 degrees. And by winding the monofilament-type steel wire around the second corrugation-imparting device 0.5 to 3 times, the monofilament-shaped steel wire to which the other corrugation has been applied by the second corrugation-imparting device Torque in a clockwise or counterclockwise direction.

As shown in FIG. 4, each of the first and second corrugation imparting devices 20 and 30 can be configured to include, for example, two gears that mesh with each other at a predetermined interval. The size and pitch of the tooth portions of the first and second corrugating device 20 and 30 can be uniform or arbitrary, but are not limited thereto. The pitches of the gears of the first and second corrugation imparting devices 20 and 30 can be different from each other, and the pitch of the gears of the first and second corrugated imparting devices 20 and 30 is smaller than the twist pitch of the cutting line (twist Pitch).

A corrugation having a predetermined pitch can be imparted to the monofilament type steel wire 10 by linearly pulling a monofilament type steel wire through the corrugation imparting means. That is, the monofilament type wire 10 is inserted into the first and second corrugation imparting devices 20 and 30, and is first and second corrugated imparting devices 20 and 30 when passing through the first and second corrugated imparting devices 20 and 30. Apply pressure to obtain a predetermined ripple. At this time, the gears of each of the first and second corrugated imparting devices 20 and 30 may be configured to be engaged with each other at a predetermined interval, so that the monofilament-type steel wire 10 is also passed through the first and second corrugated imparting devices 20 and 30. They put pressure on them.

The first ripple can be made by adjusting the rotation angles of the first and second corrugation imparting devices 20 and 30 The angle of the corrugated surface is different from the angle of the corrugated surface of the second corrugation.

During the use of the corrugated monofilament type wire for cutting, the decrease in the carrier properties of the abrasive and the decrease in the diameter of the monofilament type wire may cause a difference in the thickness of the wafer, whereas the corrugated monofilament type wire for cutting according to the present embodiment With the effect of reducing the difference in wafer thickness, the processing efficiency of the cutting process and the surface quality of the cut workpiece are considerably improved. Therefore, the corrugated monofilament type steel wire for cutting of the present embodiment can be used for cutting a workpiece requiring an ultra-high precision surface.

The invention will be described in detail below with reference to the examples, but the following examples are for illustrative purposes only and are not intended to limit the invention.

Example

Examples 1-5

A wire rod having a carbon content of 0.70 to 1.05% and a diameter of 5.5 millimeters (mm) is subjected to a drawing process twice, heat treated and plated with brass, and finally drawn to a diameter of 0.115 mm (mm). ), in order to obtain a monofilament type steel wire. Thereafter, the corrugated steel wire is pulled straight and passed through the first corrugation device. On the inlet side of the second corrugated sheeting device, a monofilament-type steel wire was wound around the first corrugated sheeting device 0.5 times to twist the monofilament-type steel wire. After the corrugation was formed, on the outlet side of the second corrugated sheeting device, the monofilament-type steel wire was wound around the second corrugated sheeting device 0.5 times to twist the monofilament-type steel wire. Thereby, the corrugations are given on two different planes. The second corrugation imparting device is supported at an angle of 100 degrees with respect to the first corrugation imparting device, and the corrugation is formed by the first corrugation imparting device. At this time, the period P of the corrugation and the height H of the corrugation The changes are shown in Table 1 below. Through this procedure, a corrugated monofilament type wire for cutting was obtained. The obtained corrugated monofilament type wire was cut in an MB264 apparatus to cut a bismuth ingot (width 156 mm × height 156 mm × length 800 mm), and the performance of the obtained corrugated monofilament type wire was evaluated. The evaluation results are listed in Table 1 below.

Comparative Example 1-2

In the same manner as in Example 1, a corrugated monofilament type wire for cutting was obtained, except that the H/P value was changed, and the H/P value is shown in Table 1 below. Various properties were evaluated, and the results of the evaluation are listed in Table 1 below.

For the defect-free surface product ratio, check the wafer for damage, scratches, color differences, and thickness differences. A wafer having no scratches, no difference in color, no difference in thickness, and a photoelectric conversion efficiency of 18% or more was evaluated as a defect-free product. All 2000 wafers were inspected and the percentage of non-defective products was calculated to be the ratio of non-defective surface products.

Example 6-10

In the HCT-B5 device, a semiconductor ingot (width 156 mm x height 156 mm x length 1900 mm) was cut. The period P of the corrugations and the height H of the corrugations were varied on a linear steel wire having a diameter of 0.130 mm as shown in Table 2 below. The cutting performance was evaluated and the evaluation results are listed in Table 2 below.

Comparative Example 3-4

A corrugated monofilament type wire for cutting was produced in the same manner as in Example 1, except for the period of the corrugation, the height of the corrugation, and the H/P value, which are shown in Table 2 below. Various properties were evaluated, and the results of the evaluation are listed in Table 2 below.

Example 11-15

A wire rod having a carbon content of 0.70 to 1.05% and a diameter of 5.5 millimeters (mm) is subjected to a drawing process twice, heat treated and plated with brass, and finally drawn to a diameter of 0.115 mm (mm). ), in order to obtain a monofilament type steel wire. Thereafter, the corrugated steel wire is pulled straight and passed through the first corrugation device. On the inlet side of the second corrugation imparting device, a monofilament-type steel wire was wound around the first corrugation-imparting device 0.5 times, and the monofilament-type steel wire was twisted in a clockwise direction. After the corrugation was formed, the monofilament-type steel wire was wound around the second corrugation-imparting device 0.5 times on the outlet side of the second corrugation-imparting device, and the monofilament-type steel wire was twisted in the clockwise direction. Thereby, the corrugations are given on two different planes. At this time, the angles between the axes of the planes in which the corrugations are formed are changed, and the changes in the angles are as shown in Table 3 below. Through this procedure, a corrugated monofilament type wire for cutting was obtained. The obtained corrugated monofilament type wire was cut in an MB264 apparatus to cut a bismuth ingot (width 156 mm × height 156 mm × length 800 mm), and the performance of the obtained corrugated monofilament type wire was evaluated. The evaluation results are listed in Table 3 below.

Comparative Example 5-6

A corrugated monofilament type wire for cutting was produced in the same manner as in Example 11 except that the planes of the planes having the corrugations were formed, and the changes of the shafts are as shown in Table 3 below. Various properties were evaluated, and the results of the evaluation are listed in Table 3 below.

For the defect-free surface product ratio, check the wafer for damage, scratches, color differences, and thickness differences. A wafer having no scratches, no difference in color, no difference in thickness, and a photoelectric conversion efficiency of 18% or more was evaluated as a defect-free product. All 2000 wafers were inspected and the percentage of non-defective products was calculated to be the ratio of non-defective surface products.

As can be seen from the results of Tables 1-3, the ratio of the defect-free surface product of the wafer using the corrugated monofilament type wire according to the present invention is significantly higher than that of the non-defective surface of the wafer-cut wafer using the comparative example. Product ratio. Moreover, the cutting speed of the embodiments according to the present invention is higher than the cutting speed of the comparative example. Therefore, the processing efficiency per unit time is improved, thereby contributing to cost reduction.

The corrugated monofilament type wire for cutting according to the present invention has a recess sufficient to grasp the abrasive, thereby providing the desired carrier properties of the abrasive, and also improving the cutting speed and the efficiency of the cutting process.

Further, since the abrasion resistance of the corrugated monofilament type steel wire is reduced due to an increase in the carrier property of the abrasive, the corrugated monofilament type steel wire for cutting according to the present invention exhibits improved life performance. Since the corrugations in a plurality of planes are imparted, the radial distribution surrounds a central axis, and the surface quality of the cut portions is considerably improved. Therefore, the corrugated monofilament type wire according to the present invention is suitable for cutting hard materials. Ingots such as semiconductors, ceramics and hard metals. Especially because the surface quality of the cut workpiece is satisfactory, it can be advantageously used for the cutting of a hard material which requires high-precision surface flatness.

The present invention has been described in detail in connection with the embodiments of the present invention and the embodiments of the present invention, and the invention may be modified and varied in various ways without departing from the spirit and scope of the invention. It is obvious that all such modifications and variations are considered to fall within the scope of the present invention.

10‧‧‧Mono wire

Claims (9)

A corrugated monofilament type wire for cutting, comprising a single metal wire, wherein the wire is formed to include a plurality of corrugations having a predetermined period, and the corrugations are formed in two or more of the longitudinal direction Plane, the height H of the corrugation divided by the value H/P of the period P of the corrugation, in the range of 3 to 12%, each plane containing an axis, and when viewed from the central axis of a corrugated monofilament type wire, The shafts are interlaced at an angle of 45 to 135 degrees, and the ratio Hc/Hi between the height Hc after cutting of the corrugated monofilament type wire for cutting and the height Hi before cutting is in the range of 0.80 to 0.95%. The corrugated monofilament type wire for cutting according to claim 1, wherein two or more corrugations formed in different planes are disposed to surround a central axis in the radial direction. The corrugated monofilament type steel wire for cutting according to claim 1, wherein the height H of the corrugation, the period P of the corrugation, and the diameter d of the corrugated monofilament type steel wire satisfy the following condition: P = 1-10 mm , d=0.03-0.5mm, and 1.2×d h 3.0 × d. The corrugated monofilament type wire for cutting according to claim 1, wherein the elongation of the corrugated monofilament type wire at the breaking point is in the range of 2.0 to 3.5%. The corrugated monofilament type steel wire for cutting according to claim 1, wherein the diameter d of the corrugated monofilament type wire for cutting is in the range of 0.110 to 0.130 mm, and the value H/P is between 3 and 11%. range. The corrugated monofilament type steel wire for cutting according to claim 1, which is a monofilament type steel wire formed by electroplating brass with carbon steel to form a copper plating layer, and the carbon content of the monofilament type steel wire is between In the range of 0.7 to 1.2 wt% (weight percent), the percentage of the steel component of the copper plating layer is in the range of 60 to 80%. The corrugated monofilament type wire for cutting according to claim 1, wherein a surface of the corrugated monofilament type wire for cutting is plated with an alloy selected from the group consisting of copper, zinc, tin, nickel, cobalt, chromium, and the like. One or more materials selected from the group consisting of. The corrugated monofilament type steel wire for cutting according to claim 7, wherein the coating material of the surface further comprises one of diamond, a cerium carbide abrasive, and a mixture thereof. A method for manufacturing a corrugated monofilament type wire for cutting, wherein a ratio Hc/Hi between a height Hc after cutting of the corrugated monofilament type wire and a height Hi before cutting is in a range of 0.80 to 0.95%, The method comprises: feeding a monofilament-shaped steel wire via a feeding unit, and imparting a plurality of corrugations to the monofilament-shaped steel wire through a first corrugating device, the first corrugating device comprising a pair of gears having a corrugation on a surface thereof a concave and convex shape, and rotating in the opposite direction; before the monofilament type steel wire is fed to a second corrugation imparting device, by winding the monofilament-shaped steel wire around the first corrugation-imparting device 0.5 Up to three times, the monofilament-type steel wire which has been corrugated by the first corrugation applying device is twisted in a clockwise or counterclockwise direction; and the second corrugated wire feeding device gives a plurality of other corrugations The second corrugation-imparting device is supported at an angle of 45 to 135 degrees with respect to the first corrugation-imparting device on the monofilament-shaped wire through which the corrugations have been formed by the first corrugation-imparting device; And winding the monofilament-type steel wire around the second corrugation-imparting device 0.5 to 3 times, and the monofilament-type steel wire to which the other corrugation has been applied by the second corrugation-imparting device is Tors in a clockwise or counterclockwise direction.