JP3471328B2 - Resin bond wire saw and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed-abrasive wire saw by resin bonding, and more particularly to a resin-bond wire saw having an improved function of preventing abrasive grains from falling off during cutting and a method for manufacturing the same.

[0002]

2. Description of the Related Art In the field of manufacturing various semiconductor devices,
Although the performance has been improved by miniaturizing the wiring pattern, the miniaturization of the wiring pattern cannot keep up with the multi-functionality, and the size of the chip itself has recently been increased. With the increase in the size of such chips, silicon wafers with a large diameter have come to be used from the viewpoint of improving the yield, and the cutting method from the silicon ingot that is the previous process is also different from the conventional inner edge cutting method. The wire saw cutting method, which is easy to handle larger diameters, is being transferred.

One of the wire saw cutting methods that has been mainly performed conventionally is a loose abrasive grain method using a slurry. This free-abrasive method runs a piano wire or ultra-high-strength alloy wire while it is in strong contact with the silicon ingot, and the free-abrasive wire such as WA or GC is applied to the part where the piano wire or ultra-high strength alloy wire is in contact. It is to cut while injecting lubricating oil containing grains. However, it is said that cutting efficiency is limited because the work environment is deteriorated due to scattering of lubricating oil and the work is contaminated, and it is not possible to control the depth of penetration of abrasive grains into the work material to be uniform. There is.

On the other hand, in recent years, a fixed abrasive method using a wire saw in which abrasive particles such as WA, GC, diamond, and CBN are fixed to the peripheral surface of the core wire has been proposed. Known wire saws used in this fixed abrasive method include electrodeposition wire saws that fix the abrasive particles by electrodeposition and resin bond wire saws that fix the abrasive particles using a resin (resin) as a binder. Even with these electrodeposited wire saws and resin bond wire saws, it is possible to cut with abrasive grains by causing the material to travel while making strong contact with the workpiece, as in the free abrasive grain method.

By the way, since the electrodeposition wire saw spends time in the plating process for electrodepositing the abrasive grains, several tens to several hundreds of k
It has been pointed out previously that there is a manufacturing problem that it is virtually impossible to electrodeposit abrasive grains on the m core wire, and that a wire breakage easily occurs during processing due to low breaking torsional strength and bending strength. It was Therefore, there is a history that a resin bond wire saw was developed as a solution to the above drawbacks of the electrodeposition wire saw.

An example of such a resin bond wire saw is disclosed in Japanese Patent Laid-Open No. 10-138114. The resin bond wire saw described in this publication has a structure in which a high tensile strength metal wire is used as a core wire, and a polyamideimide resin is used as a binder in which abrasive grains are dispersed and contained to coat the core wire. According to such a resin bond wire saw, it is possible to manufacture a long-distance wire saw that was difficult with the electrodeposition wire saw.

[0007]

By the way, when cutting a silicon ingot or the like using a wire saw, the abrasive grains are likely to fall off due to abrasion or vibration of the resin layer due to contact with the workpiece. There is. To solve this problem, Japanese Unexamined Patent Publication (Kokai) No. 10-328932 proposes a wire saw in which fine dents are formed on the surface of a core wire and abrasive grains are inserted into the dents and fixed to the core wire.

The wire saw described in the above publication forms a myriad of satin-shaped depressions on the surface of the core wire by mechanical treatment such as sand blasting or shot peening, or electrochemical treatment such as chemical polishing or electrolytic polishing, and bonds with the abrasive grains. It is manufactured by a method of applying a mixture of agents to the surface of the core wire, squeezing this with a die to make the abrasive grains enter the recesses to make the outer diameter uniform, and fixing the abrasive grains and the binder to the core wire by baking. is there. It is said that such a wire saw can sufficiently withstand the reaction force of the workpiece during cutting even if the reaction force acts on the abrasive grains.

However, in the wire saw described in the above publication, although an increase in the adhesive force between the core wire and the resin layer due to the increase in the surface area of the core wire due to the formation of the recess can be expected, the abrasive grains only enter the recess. Therefore, the effect of preventing the abrasive grains themselves from falling off cannot be expected so much. Further, when the recess is formed by mechanical treatment, the core wire may be damaged and the wire saw may be broken during the cutting process. Although the electrochemical treatment rarely damages the core wire, it is difficult to form enough recesses to prevent the abrasive grains from falling off.

On the other hand, in addition to the method described in the above publication, a special layer for adhesion corresponding to a ground layer of a grindstone is formed on the surface of the core wire, or a surface modifier such as a coupling treatment is used to form the core wire and the resin layer. A method of sandwiching an adhesive layer between and is also conceivable. However, even in this method, the effect is mixed due to the compatibility between the core wire material and the resin material, and the effect itself is slight.

An object to be solved by the present invention is to increase the adhesive force of the abrasive grains to the core wire in the resin bond wire saw to prevent the abrasive grains from falling off during the cutting process.

[0012]

DISCLOSURE OF THE INVENTION The present invention is a resin bond wire saw in which abrasive grains are fixed to the surface of a core wire using a resin as a binder, and a multi-layered spiral wire is formed on a soft metal plating layer applied to the core wire. A wire saw in which grooves are formed, and a part of abrasive grains is embedded in the multiple grooves.

Although a high tensile strength metal wire such as a piano wire is used as the core wire of the wire saw, in the present invention, the surface of the high tensile strength metal is plated with a soft metal such as copper or a copper alloy, and the soft metal plating is performed. Multiple spiral grooves are formed in the layer. After coating the mixture of liquid resin and abrasive grains on the surface where spiral multiple grooves are formed, pull out by passing through a die with a predetermined inner diameter, resulting in a large grain size in the mixture of liquid resin and abrasive grains. Part of the abrasive grains fits into the spiral groove, and then the resin layer is cured,
The wire saw has a large number of abrasive grains spirally arranged along the multiple grooves.

It is relatively large abrasive grains in the abrasive grain layer that are likely to be loaded that easily fall off during the cutting process. In the wire saw of the present invention, large abrasive grains are partly fitted in the multiple grooves formed in the soft metal plating layer of the core wire, and the abrasive grains are also caused by abrasion or vibration of the resin layer during cutting. It will not fall out. Further, since the large abrasive grains are arranged in a spiral shape, the discharge of the chips becomes good.

The thickness of the soft metal plating layer is preferably in the range of 1/40 to 1/10 of the wire diameter of the high tensile strength metal wire which is the core material of the core wire. If the thickness of the soft metal plating layer is smaller than the above range, the embedding depth of the abrasive grains is too small, and the effect of preventing falling off cannot be expected. If the thickness of the soft metal plating layer is larger than the above range and the outer diameter is the same as the conventional product, the high tensile strength metal wire of the core material becomes too thin for the diameter of the metal-plated core wire, resulting in the required strength of the core wire. The above range is preferable because the result will be below.

In this soft metal plating layer, multiple grooves having a depth of 2/5 to 4/5 of the thickness of the soft metal plating layer are formed.
Abrasive grains having a grain size not more than four times the groove depth are used. If the depth of the groove is less than 2/5 of the thickness of the soft metal plating layer, the embedding depth of the abrasive grains is too small and the fall prevention effect cannot be expected.
If it is larger than 5, the high tensile strength metal wire may be damaged in the step of forming the spiral multi-shaped groove, so the above range is preferable. By forming spiral multiple grooves only in this soft metal plating layer and burying a part of the abrasive grains,
There is no damage to the high tensile strength metal wire as the core material, and there is no fear of breaking the wire saw.

The resin bond wire saw of the present invention comprises a step of forming a spiral multi-slot in a soft metal plating layer while feeding a core wire obtained by plating a high tensile strength metal wire with soft metal at a constant speed, A step of passing a core wire formed with a spiral multi-slot through a container containing a mixture of abrasive grains and a liquid resin to coat the core wire with a mixture of abrasive grains and a liquid resin, and a core wire coated with the mixture Can be manufactured by a manufacturing method including a step of passing a die having a predetermined inner diameter and a step of curing the liquid resin after passing through the die to fix the abrasive grain layer to the core wire.

Here, as a method for forming spiral multiple grooves in the soft metal plating layer of the core wire, the core wire fed at a constant speed is sandwiched by grinding tools and the core wire and the grinding tool are relatively rotated. The method can be adopted. As the grinding tool, for example, a grindstone in which abrasive grains of grain size # 30-400 are arranged at a constant pitch, a polishing cloth with abrasive grains (or a polishing plate),
A comb-shaped cutting tool or the like can be used.

The drawing process using the die can be performed by using a die used for adjusting the wire diameter in the conventional wire saw manufacturing process. By selecting the inner diameter of the die appropriately, it will be embedded in the groove of multiple threads in order from the larger grain size when passing through the die, and after passing through the die, large grain at a constant pitch in the length direction of the core wire. Are arranged in a spiral shape.

The soft metal plating layer of the core wire is formed by metal plating a high tensile strength metal wire as a core material. As the plating metal, gold, tin, zinc or an alloy thereof can be used in addition to copper or a copper alloy. Further, it is desirable to use a photocurable resin as the liquid resin. By using the photocurable resin, the curing time of the liquid resin can be shortened and the production efficiency can be increased.

[0021]

1 is a partial front view of a wire saw according to an embodiment of the present invention, and FIG. 2 is a vertical sectional view taken along the line AA of FIG.

The wire saw of this embodiment has a core wire 1 and an abrasive grain layer 2 fixed thereto. The core wire 1 is a piano wire 1a having a wire diameter of 200 μm plated with a Cu—Zn alloy, and a plated layer 1b. Is a soft metal layer having a thickness of 5 μm. The abrasive grain layer 2 is formed by fixing the abrasive grains 2b by the bond layer 2a. The bond layer 2a is a resin bond in which a filler material is mixed with an acrylate resin to which a photoradical generator is added, and the abrasive grains 2b are diamond abrasive grains having an average particle diameter of 15 μm.

FIG. 3 is a view showing a spiral multiple groove formed in the plated layer of the core wire, and FIG. 4 is a view showing the appearance of the abrasive grain layer. In the wire saw of the present embodiment, a spiral multi-thread groove 3 is formed in the plated layer 1b of the core wire 1, and the groove 3
Part of the abrasive grains 2b is embedded in the. The multi-slot groove 3 is a groove forming tool 1 in which the core wire 1 is sandwiched by the grinding tool 13a (see (a) of FIG. 5) while the core wire 1 is being fed at a constant speed.
The groove 3 is formed by rotating the groove 3.

To partially embed the abrasive grains 2b in the groove 3, the core 1 is coated with the bond layer 2a together with the abrasive grains 2b, and then the die 1 is formed.
4a (see FIG. 5C), the outer diameter of the coated wire is adjusted together with the removal of the excess coating layer. Abrasive grain layer 2 in which liquid resin is cured after passing through the die 14a
4, as shown in FIG. 4, the abrasive grains D having a large grain diameter preferentially fit into the groove 3 and the large abrasive grains D are arranged in a multi-screw spiral shape, and the small abrasive grains D are interposed therebetween. d is provided. As a result, the abrasive grains 2b will not fall off due to wear or vibration of the bond layer 2a during cutting. Moreover, since the large abrasive grains D are arranged in a spiral shape, the discharge of the chips becomes good. Furthermore, plated layer 1
Since the surface area of b is large, the adhesive force of the bond layer 2a with respect to the plating layer 1b increases, and peeling of the bond layer 2a is prevented.

5A and 5B are views showing a manufacturing process of the wire saw according to the present invention. FIG. 5A is a schematic view of the entire apparatus, FIG. 5B is a schematic configuration view of a groove forming tool, and FIG. 5C is a coating layer forming apparatus. It is a figure which shows the state in the output side. The main steps of the manufacturing method are as follows. The core wire 12 unwound from the reel 11 is fed at a constant speed and passed through the groove forming tool 13 to form multiple grooves 3 on the surface of the core wire 12. Groove forming tool 1
No. 3 was prepared by arranging A type abrasive grains of grain size # 270 at a constant pitch.
A set of a pair of grinding tools 13a is provided inside the rotary frame 13b. The grinding tool 13a is pressed in the direction of arrow B in FIG. 2 (b) to sandwich the core wire 12 with the grinding tool 13a, and the rotary frame 13b is shown. By rotating in the direction of arrow C of 2 (a), multiple grooves 3 with a constant pitch are formed in the core wire 12.

Next, the core wire 12 having the groove 3 formed therein is provided with a container 14b containing a mixture of abrasive grains and a liquid resin and a die 14a.
The coating layer forming device 14 in which the above are combined is passed to form a coating layer of a mixture of abrasive grains and liquid resin on the core wire 12. As shown in FIG. 2 (c), large abrasive grains D and small abrasive grains d are randomly distributed on the core wire surface after passing through the container 14 b containing the mixture of the abrasive grains and the liquid resin in the coating layer forming apparatus 14. However, when passing through the die 14a, the large abrasive grains D preferentially fit into the multiple grooves 3 and the large abrasive grains D are arranged in a multiple spiral shape. And a small abrasive grain d is arranged between them. In the case of this embodiment, the finished outer diameter after passing through the die 14a is 210 μm.
± 10 μm.

Then, the coated wire 15 in which the coating layer of the core wire 1 is made uniform in thickness by the die 14a is sent to the ultraviolet irradiation device 16 and is irradiated with ultraviolet rays to cure the liquid resin in the coating layer to thereby polish the abrasive layer 2. Is formed into a wire saw 17 and wound on a reel 18 to obtain a product.

[Test Example] In order to confirm the effect of the present invention, the wire saw (invention product 1) of the above embodiment, the core wire plating layer thickness 20 μm, groove thickness 16 μm, and abrasive grain average particle size A cutting test was performed under the following test conditions using a wire saw (invention product 2) in which a part of abrasive grains was embedded in multiple grooves of 40 μm and a wire saw (conventional product) without forming grooves on the plating layer surface. went. Cutting device: Single wire cutting device Wire speed: Average 400m / min Wire tension: 19.6N Workpiece: Silicon ingot

Table 1 shows the state of removal of the abrasive grains of the wire saw when the number of cut-out sheets is 50 and the total number of cut-out pieces that can be cut out with a predetermined processing accuracy.

[Table 1] Note) The number of abrasive grains dropped is the number of abrasive grains dropped in a 1 mm length of wire saw measured by microscope observation.

As can be seen from Table 1, in the invention products 1 and 2, the abrasive grains were less likely to fall off than in the conventional products, and the total number of pieces cut out was 2-3 times that of the conventional products. The effect of the thickness of the plating layer was confirmed to be such that the thicker the plating layer, the larger the amount of embedding of the abrasive grains and the higher the retaining force of the abrasive grains.

[0031]

EFFECTS OF THE INVENTION By forming a spiral multiple groove in the soft metal layer of the core wire of the resin bond wire saw on which the soft metal plating is applied, and embedding a part of the abrasive grains in this multiple groove, Part of the grains fits into the groove on the surface of the soft metal layer, and the abrasive grains will not fall off due to abrasion or vibration of the resin layer during cutting processing, thus extending the life of the wire saw. . Further, since the large abrasive grains are arranged in a spiral shape, the discharge of the chips becomes good.

[Brief description of drawings]

FIG. 1 is a partial front view of a wire saw according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view taken along the line AA of FIG.

FIG. 3 is a view showing a spiral multiple groove formed in a plated layer of a core wire.

FIG. 4 is a diagram showing an external appearance of an abrasive grain layer.

FIG. 5 is a diagram showing a wire saw manufacturing process according to the present invention, in which (a) is a schematic diagram of the entire apparatus, (b) is a schematic configuration diagram of a groove forming tool, and (c) is an outlet side of the coating layer forming apparatus. It is a figure which shows the state in.

[Explanation of symbols]

1 core wire 1a piano wire 1b plating layer 2 Abrasive layer 2a bond layer 2b Abrasive grain 3 Multi-slot 11 reels 12 core wire 13 Groove forming tool 13a Grinding tool 13b rotating frame 14 Coating layer forming device 14a dice 14b container 15 coated wire 16 UV irradiation device 17 wire saw 18 reel Large abrasive grains d Small abrasive grains

Continuation of the front page (56) Reference JP 2000-52226 (JP, A) JP 2000-246542 (JP, A) JP 10-138114 (JP, A) JP 9-150314 (JP, A) ) Japanese Patent Laid-Open No. 7-96454 (JP, A) Actual Development 4-79050 (JP, U) Registered Utility Model 3001562 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B23D 61 / 18 B24B 27/06 B24D 3/00 B24D 11/00 B28D 5/04

Claims (6)

(57) [Claims] 1. A resin bond wire saw in which abrasive grains are fixed to the surface of a core wire using a resin as a binder, wherein a spiral multiple groove is formed in a soft metal plating layer applied to the core wire.
A resin bond wire saw in which a part of abrasive grains is embedded in the multiple grooves. 2. The thickness of the soft metal plating layer is 1/40 to 1/10 of the wire diameter of the high tensile strength metal wire as the core material of the core wire, and the depth of the multi-slot groove is the soft metal. The resin bond wire saw according to claim 1, wherein the thickness is 2/5 to 4/5 of the thickness of the plating layer. 3. A step of forming a spiral multi-slot in a soft metal plating layer while feeding a core wire obtained by plating a high tensile strength metal wire with a soft metal at a constant speed, and a step of forming the spiral multi-strip groove in the soft metal plating layer. The step of coating the core wire formed with the groove with the mixture of the abrasive particles and the liquid resin by passing the container containing the mixture of the abrasive particles and the liquid resin, and the core wire in the state of being coated with the mixture is a die having a predetermined inner diameter. And a step of curing the liquid resin that has passed through the die to fix the abrasive grain layer to the core wire, the method for manufacturing a resin bond wire saw. 4. The thickness is 1/1 of the wire diameter of the high tensile strength metal wire.
Forming multiple grooves having a depth of 2/5 to 4/5 of the thickness of the soft metal plating layer on the soft metal plating layer of 40 to 1/10,
The method for manufacturing a resin bond wire saw according to claim 3, wherein abrasive grains having a grain diameter of 4 times or less the groove depth are used. 5. A spiral multi-row groove is formed in a soft metal plating layer of a core wire by sandwiching a core wire sent at a constant speed with a grinding tool and rotating the core wire and the grinding tool relative to each other. 3. The method for manufacturing the resin bond wire saw according to item 3. 6. The method for manufacturing a resin bond wire saw according to claim 3, wherein a photocurable resin is used as the liquid resin.