KR20000033534A - Diamond electrodeposition wire for cutting brittle material and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a diamond electrodeposition wire used as a cutting tool for hard brittle materials such as silicon ingots and the like.

The diamond electrodeposition wire of the present invention is a diamond particle formed on the surface of the wrapping core wire formed of at least one strand of steel wire wound spirally around a core wire at a constant pitch, and the wrapping core wire wound around the core wire. Comprising a secondary plating layer comprising a, wherein the outer surface of the secondary plating layer is made of a structure in which a chip pocket consisting of a spiral groove portion is formed, the wire of the present invention is at least one strand of wrapping wire at a constant pitch around the core wire It is manufactured by a series of processes to obtain the lapping core wire by winding and then electrodeposition of diamond particles together with the precipitation of metal in the process of plating the surface of the wrapping core wire with a metal plating solution.

As the wrapping diamond electrodeposition wire of the present invention is formed with chip pockets spirally inserted into the surface portion, the cutting slurry is smoothly discharged when cutting brittle material, thereby greatly improving the cutting performance. There is an advantage that cutting is possible without disconnection, there is an effect that can reduce the time required for the polishing process by minimizing the cutting trace on the cutting surface.

Description

Diamond electrodeposition wire for cutting brittle material and manufacturing method thereof

The present invention relates to a diamond electrodeposition wire used for cutting a hard brittle material, and more particularly, diamonds in the form of a plating layer such as nickel on the surface of a wrapping core wire formed by winding at least one strand of the wrapping core wire in a spiral around the core wire of one strand. By the electrodeposition of the particles together, the chip pocket in the shape of the spiral indentation formed on the outer circumferential surface of the wire prevents contamination of the cutting surface of the workpiece or blockage of the cutting slurry during cutting of the brittle material and exerts excellent cutting ability. A diamond electrodeposition wire and a manufacturing method thereof.

In general, conventional tools used for cutting hard brittle materials such as silicon, gallium-arsenide ingots, and glass, which are used as semiconductor materials, include disk-shaped blade saws, glass powders, etc. BACKGROUND ART Diamond electrodeposited wires, in which diamond particles are electrodeposited on wire surfaces such as multi-wire saws and piano wires, which allow a plurality of wires to pass through a cutting surface while supplying a cutting slurry to a cutting part, are known.

Among the conventional brittle material cutting tools, the blade saw has excellent cutting ability, but wear of the diamond particles or clogging of the slurry during the cutting occurs badly, resulting in a poor workability and a large trace of cracks on the cutting surface. In addition, as the silicon ingot has recently been enlarged, the blade saw has also been enlarged (larger diameter) and the thickness of the blade has been thinned to reduce cutting loss. Since it is being used with 8 inches and is expected to be 12 inches or more in the future, there is a limit to thinning of the blade corresponding thereto.

In addition, in the case of a multi-wire saw using a cutting slurry, it is easy to contaminate the workpiece due to the mixing of light oil with the slurry turbid liquid, and the waste slurry turbid liquid generated during the cutting process is difficult to cause environmental pollution. In addition, the disadvantage that the cutting speed is slow and the cutting surface is also pointed out.

On the other hand, diamond electrodeposition wire is widely used as a tool for cutting semiconductor materials, such as silicon ingots, due to the fact that it produces less processing cracks on the cutting surface of the workpiece than the other brittle material cutting tools and has a relatively high precision. Bar, looking at some of the typical diamond electrodeposition wire as follows.

First, Japanese Patent Laid-Open No. 62-260006 discloses a diamond electrodeposition wire in which diamond particles are physically embedded in the surface of a piano wire rod by heat-treating the surface of the piano wire into a soft ferrite structure. It is known that many defects (cracks and scratches) are likely to cause disconnection during cutting, which causes many problems in practical use.

Next, a diamond electrodeposition wire in which diamond particles are electrodeposited at the same time when the plating layer is formed on the surface of the piano wire, such a wire is provided in the form of an endless wire between two rollers, and is rotated by the driving roller. The cutting material is cut on the wire transfer path while the wire is continuously transferred. The diamond electrodeposited wire of this type has the advantage of being relatively easy to manufacture and cutting of large diameter workpieces, but the slurry breakage occurs during cutting, and when the ingot of 8 inches or more is cut, the wire breaks during cutting. It occurs, or the peeling of the plating layer and the falling off of the diamond particles are generated, there is a problem that the cutting traces are large and rough cut surface is formed to take a lot of time to polish the silicon wafer after cutting.

In addition, as a structure different from the diamond electrodeposition wire, Japanese Laid-Open Patent Publication No. 7-96455 has a nickel plated layer formed on a piano wire, and then coated a resin layer such as fluorine resin on the piano wire. A helical diamond electrodeposition wire is disclosed in which spirally removed and electrodeposited diamond particles with the formation of a secondary plating layer selectively on an exposed plating layer. However, the diamond electrodeposition wire of the above-described form includes a process of forming a resin coating layer during the fabrication process and sequential removal of the resin coating layer in a spiral manner. There are a lot of problems.

Accordingly, the present invention is to solve the above-mentioned problems pointed out in the diamond electrodeposition wire conventionally used for cutting the hard brittle material, the wrapping core is formed by winding at least one strand of the wrapping core in a spiral around the core of the strand In forming a plating layer of nickel or the like on the surface of the electrode, diamond particles are electrodeposited together to form chip pockets on the outer circumferential surface of the wire, thereby preventing contamination of the cutting surface of the workpiece or clogging of the cutting slurry when cutting brittle materials, and excellent cutting ability. An object of the present invention is to provide a diamond electrodeposition wire for cutting brittle material and a method for producing the same.

1 is a partially cutaway front view of an embodiment diamond electrodeposition wire of the present invention.

2 is a sectional view taken along the line A-A to E-E of FIG.

Figure 3 is a perspective view showing the appearance of one embodiment diamond electrodeposition wire of the present invention.

Figure 4 is a partially cut away front view of another embodiment diamond electrodeposition wire of the present invention.

Figure 5 is a schematic structural diagram of a twisted pair apparatus showing an embodiment of the wrapping core wire manufacturing process of the present invention.

Figure 6 is a graph showing the cutting efficiency according to the pitch change of the diamond electrodeposition wire of the present invention compared with the conventional single-wire diamond electrodeposition wire.

7 is a graph showing the cutting efficiency behavior according to the pitch and the cutting frequency of the diamond electrodeposition wire of the present invention.

((Description of the code for the main part of the drawing))

1. Core wire 2. Wrapping wire

3. Wrapping core 4. Diamond grain

5. Secondary plating layer 6. Chip pocket

The object of the present invention is a straight core wire made of a single strand of piano wire, a wrapping element wire made of at least one strand of piano wire or steel wire wound in a spiral at a constant pitch around the core wire, and a wrapping element wire around the core wire It is achieved by a diamond electrodeposition wire structure composed of a secondary plating layer containing diamond particles formed on the surface of the wrapped core wire wound.

At this time, the core wire is mainly used high strength piano wire, the diameter is preferably in the range of 0.05-2.0mm, the wrapping wire is preferably a piano wire or steel wire having a diameter of 0.03-0.15mm.

In the wrapping element wire constituting the wrapping core wire, one strand or two to five strands of wires are wound spirally around the core wire while maintaining a penetration angle of 30 ° to 60 ° around the core wire. When the wrapping element wire is a steel element wire, primary base plating is performed by copper, tin, or nickel plating before lapping, and the thickness of the plating layer formed at this time is preferably maintained at 5 μm or less.

However, if the wrapping wire is not a steel wire, it is not necessary to carry out the first base plating.In some cases, even if the wrapping wire that forms the wrapping core wire is a steel wire, the first undercoating is carried out after lapping. It may be done before.

As the primary plating method of the steel element used as the wrapping element wire, various plating methods such as electroless plating or electroplating may be used, and there is no particular limitation on the plating method. On the other hand, when the primary plating is performed before lapping, there is no rust and the primary plating can be carried out, followed by winding on a spool, and the secondary plating can be performed continuously with lapping as a subsequent step.

However, in the method of performing the primary plating and the secondary plating after lapping, the whole process is performed continuously. Therefore, when better adhesion of plating is required, it is more effective to carry out primary plating, lapping, and then secondary plating.

The wire manufacturing process, including the object and technical configuration of the present invention and the effects thereof according to the present invention will be clearly understood by the following detailed description with reference to the drawings showing a preferred embodiment of the present invention.

First, Figure 1 is a partially cutaway front view of an embodiment diamond electrodeposition wire of the present invention, A-E of Figure 2 is a cross-sectional view taken along line AA to EE of Figure 1, Figure 3 is an embodiment diamond electrodeposition wire of the present invention It is a perspective view showing the appearance of the.

As shown in the drawing, the diamond electrodeposition wire of the present invention comprises a straight core wire 1 made of a single strand of piano wire and a strand of piano wire or steel wire wound spirally at a constant pitch around the core wire 1. It consists of the lapping element wire 2 and the secondary plating layer 5 containing the diamond grains 4 formed in the surface of the lapping core wire 3 by which the lapping element wire 2 was wound around the core wire 1. .

At this time, the diameter (dc) of the core wire 1 constituting the wrapping core wire (3) is 0.05 -2.0mm, the diameter (dw) of the wrapping wire 2 is maintained in the range 0.03-0.15mm, such a The pitch P _wrap of the wrapping core wire 3 is preferably formed to satisfy the following equation.

P _wrap = dc × (1.5 to 12.0)

The lapping core 3 is a secondary plating layer formed on such an outer circumferential surface as the outer circumferential surface is formed by the wrapping element wires 2 spirally wound around the core wire 1 so that its outer circumferential surface is a spiral recess and a spiral protrusion. The outer circumferential shape of (5) also forms a concave-convex curved surface formed by alternating spiral convex portions and spiral convex portions, and such a spiral concave portion of the secondary plating layer 5 forms a chip pocket 6.

The secondary plating layer 5 is nickel or equivalent and its thickness is about 20-60 μm, and the particle size of the diamond electrodeposited together with the plating layer in the process of forming the secondary plating layer 5 is about 20-60 μm. Accordingly, the diamond particles 4 usually have a portion embedded in the secondary plating layer 5 and the remaining portions protrude out of the secondary plating layer 5.

The secondary plating layer 5 is connected to the negative electrode to the wrapping core wire 3 and the positive electrode to the plating solution in the state in which the diamond particles 4 having the size of 20 to 60 μm are added to the electroplating bath, and thus the plating time and the current density are reduced. It is obtained by adjusting appropriately. At this time, the electrodeposition of the diamond particles (3) is made in the first or second tank of the secondary plating bath, for example, after the electrodeposited diamond particles together with the plating solution in the first bath, in the second bath, the metal is deposited from the metal plating solution. By allowing precipitation, diamond particles can be more firmly fixed while maintaining the thickness of the plating layer at 30 μm or more.

Next, FIG. 4 is a partially cutaway front view showing another embodiment diamond electrodeposition wire structure of the present invention, in which the diamond electrode wire of this embodiment as shown is a core wire (1) compared to the embodiment structure of FIGS. All other structures are the same except for the configuration in which the wrapping element wires 2a and 2b wound around) are two strands.

The manufacturing process of the diamond electrodeposition wire for cutting the brittle material of the present invention is as follows.

The diamond electrodeposition wire manufacturing process of the present invention comprises the steps of winding the wrapping wire 2 around the core wire 1 to produce the wrapping core wire 3, and the secondary plating on the entire surface of the wrapping core wire 3; It consists of a two-step process of the electrodeposition of the diamond particles together.

First, the manufacturing step of the wrapping core wire (3) of the first step is a core wire (1) by performing a series of processes leading to electrolytic degreasing, washing, pickling, primary plating, washing, drying, the core wire and the wire for wrapping wire And a wrapping element wire 2, and then the core wire 1 is wound around the supply bobbin 7 and the wrapping element wire 2 is wound around the spool 8, as shown in FIG. The spool 8 on which the wrapping wire 2 is wound is installed on the moving path of the core wire 1 drawn out and wound around the winding bobbin 11 via a plurality of guide rollers 9a-9d and the capstan 10. Lapping having a constant wrapping pitch (P _wrap ) around the core wire 1 by feeding the wrapping wire 2 toward the core wire 1 while rotating the spool 8 around the core wire 1 in motion. The core wire 3 is obtained.

At this time, the primary plating on the element wire 1 and the wrapping core wire 2 may be performed after the molding is completed to the wrapping core wire 3.

And, the adjustment of the wrapping pitch (P _wrap ) can be adjusted by adjusting the moving speed of the core wire 1 and the rotational speed of the spool 8, the wrapping element wire (2) wound around the core wire (1) If more than two strands are to be provided, a corresponding number of spools 8 may be installed on the moving path of the core wire 1.

When the lapping core 3 is obtained through such a process, secondary plating is performed around the lapping core 3 as a two-step process. The specific process is as follows.

First, degreasing, rinsing, and pickling are sequentially performed on the lapping core wires 3 supplied from the supply table, followed by secondary plating in a plating bath containing diamond particles to form a secondary plating layer around the lapping core wires 3. In addition, the electrodeposition of the diamond particles 4 is carried out together, followed by washing and drying to prepare the diamond electrodeposition wire for cutting brittle material of the present invention.

The secondary plating may be both electroplating or chemical plating, but electroplating is preferable to chemical plating in terms of plating adhesion.

Embodiments of the present invention are as follows.

Lapping core wire of 0.1mm wire diameter and 0.1mm wire diameter was subjected to pretreatment before lapping, and then tin-plated with methylsulfonic acid bath and nickel plating with sulfuric acid bath to change the pitch at regular intervals to make the wrapping core wire. .

Subsequently, secondary plating was performed on the lapping core wire, wherein the plating bath was nickel-plated with the same sulfuric acid bath as the primary plating so that diamond having a particle size of 40 μm was uniformly deposited at the same time as nickel plating. To obtain a wire on which diamond particles were electrodeposited.

At this time, the number of strands of the wrapping element wire wound on the core wire was changed to 2 strands, 3 strands and 4 strands in the same process as the above manufacturing process to produce a plurality of diamond electrodeposition wires different from each other.

The cut test for the silicon ingot was performed using the diamond electrodeposition wire of this invention obtained in this way.

The silicon ingots used in the test were 6 inches and 8 inches in diameter, and 5 diamond electrodeposition wires for cutting were placed parallel to each other at intervals of 1 mm to move the wires at a movement speed of 350 m / min. Cutting was made.

As a result of comparing the cut surface of the silicon wafer thus obtained with the silicon wafer cut with the conventional diamond electrodeposition wire, the wafer obtained by the diamond electrodeposition wire of the present invention had much less cutting traces, and thus the polishing time on the wafer surface after cutting. Could be reduced more than twice.

6 is a graph showing the cutting ability of the lapping diamond electrodeposition wire of the present invention and the conventional single-wire diamond front electrodeposition wire, the lapping diamond electrodeposition wire of the present invention is about 3.5 times improved compared to the conventional single-wire diamond electrodeposition wire In the example wires of the present invention, the smaller the lapping pitch, the better the cutting performance.

On the other hand, Figure 7 is a graph showing the change in cutting efficiency according to the lapping pitch and the cutting frequency of the lapping diamond wire of the present invention, it can be seen that the cutting efficiency is improved as the lapping pitch is smaller and the cutting frequency is increased.

As described above, since the wrapping diamond electrodeposition wire of the present invention is manufactured through a simple manufacturing process, the manufacturing cost can be reduced, and the chip pockets spirally recessed on the surface thereof form brittle silicon ingots. When cutting materials, the cutting slurry is smoothly discharged, which greatly improves the cutting performance compared to the conventional electrodeposited wires without chip pockets, and also enables cutting without large wire breakage even in large diameter silicon ingots. .

In addition, when cutting the brittle material using the lapping diamond electrodeposition wire of the present invention by minimizing the cutting traces on the cutting surface, it is possible to reduce the time and effort required in the subsequent polishing process, and the water-based instead of light oil when cutting Since the use of cutting oil can be used, the contamination of the workpiece can be avoided, and the waste water treatment can be easily performed.

Claims (4)

Diamond particles formed on the surface of the wrapping core wire formed of a straight core wire made of one strand of steel wire, at least one strand of steel wire wound spirally around the core wire with a constant pitch, and the wrapping core wire wound around the core wire. Comprising a secondary plating layer comprising a diamond electrode for cutting the brittle material, characterized in that the outer surface of the secondary plating layer is formed a chip pocket consisting of a spiral groove. The diamond electrodeposition wire for cutting brittle material according to claim 1, wherein the core wire and the surface of the wrapping wire, which form the lapping core, are formed with a nickel, copper or tin plating layer. Wrapping at least one strand of wrapping wire at a constant pitch around the core of a strand to obtain a wrapping core, and then depositing metal and electrodeposition of diamond particles in the process of plating the surface of the wrapping core with a metal plating solution Method for producing a diamond electrodeposited wire for cutting brittle material. The method of manufacturing a diamond electrodeposited wire for cutting brittle material according to claim 3, wherein the core wire and the wrapping wire are first plated with copper, tin, nickel, or the like before or after lapping.