JP2000296471A - Resin-bond wire saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency in cutting by retaining abrasive grains stably without degrading the bending characteristic of core wires. SOLUTION: This resin-bond wire saw comprises a wire core 1 to which segment chips 2 of a resin including abrasive grains 2d and filler 2c for strength/ hardness reinforcement are integrally bonded at axial intervals along the wire core 1. The resin is a liquid polymer having an addition ratio of the filler 2c ranging from 5 to 50% by volume or a degree of concentration of the abrasive grains 2d ranging from 150 to 200 leading to high strength and hardness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed-abrasive type wire saw using a resin bond, and more particularly to a resin bond wire saw having high strength and hardness and good bendability.

[0002]

2. Description of the Related Art In the field of manufacturing various semiconductor devices,
Although the performance has been improved by miniaturization of the wiring pattern, the miniaturization of the wiring pattern alone cannot keep up with the multifunctionality. Recently, the size of the chip itself has been increased. With the increase in the size of such chips, silicon wafers with large diameters have come to be used from the viewpoint of improving the yield, and the cutting method from the silicon ingot, which is the preceding process, has also been changed from the conventional inner peripheral blade cutting method. The transition to the wire cut method, which is easy to handle large diameters, is beginning.

[0003] As one of the wire cutting methods which has been mainly performed conventionally, there is a loose abrasive method using a slurry. In this loose abrasive method, a piano wire or an ultra-high strength alloy wire is run in strong contact with a silicon ingot, and a free abrasive such as WA or GC is applied to a portion where the piano wire or the ultra-high strength alloy wire is in contact. Cutting is performed while lubricating oil containing particles is injected. However, it is said that the cutting efficiency is limited because the work environment is degraded due to the scattering of the lubricating oil and the work is contaminated, and the cutting depth of the abrasive grains cannot be controlled to be uniform.

On the other hand, in recent years, a fixed abrasive method using a wire saw in which abrasive grains of WA, GC, or diamond are integrally joined to a peripheral surface of a core wire has been proposed. As a wire saw used in the fixed abrasive method, an electrodeposition wire saw for joining abrasive grains by electrodeposition and a resin bond wire saw for joining abrasive grains using a polymer organic material as a binder are known. Even with these electrodeposited wire saws and resin bond wire saws, cutting by abrasive grains is possible by running while strongly contacting the work as in the case of the free abrasive grain method.

[0005] Electrodeposited wire saws take time in the plating process for electrodepositing abrasive grains and are difficult to elongate, and they suffer from breakage during processing due to low breaking torsional strength and bending strength. The problem of ease of use has been pointed out before. Therefore, a resin-bonded wire saw has been developed as an improvement over the disadvantages of the electrodeposited wire.

As such a resin bond wire saw, for example, there is a resin bond wire saw described in JP-A-10-138114. The resin bond wire saw described in this publication uses a high-strength metal as a core wire and coats the core wire with an abrasive material dispersed and contained therein using an organic material such as polyamide or polyimide resin or an inorganic material such as glass as a binder. It is a configuration that does.

[0007]

The resin bond wire saw has a tendency for the abrasive grain layer to peel off more easily than the electrodeposited wire saw. For this reason, the resin-bonded wire saw wears more heavily than the electrodeposited wire saw, and there is a surface that cannot withstand the cutting of the silicon ingot. Therefore, in order to suppress the peeling of the abrasive layer, it is considered that increasing the hardness of the resin bond layer is one effective means.

However, when the hardness of the resin bond layer is increased, the entire peripheral surface of the core wire is continuously covered with a hard film over the entire length, so that the flexibility of the core wire is greatly reduced. On the other hand, since the wire saw is wound around a pulley having a groove formed on its peripheral surface and is installed in a cutting device in which a loop is formed, the wire saw is largely bent around the pulley. Further, since the vehicle travels while being pressed against the work, it is bent and deformed by a reaction force from the work. Therefore, in a wire saw having a resin bond layer having a high hardness, the core wire itself flexes flexibly following the peripheral surface of the pulley or the surface of the work, but generates or cracks minute cracks in the resin bond layer. For this reason, the abrasive grains are liable to fall off and cause a break in the core wire, and the falloff of the abrasive grains not only lowers the cutting efficiency but also deteriorates the cut surface of the work.

[0009] As described above, in the resin bond wire saw, increasing the fixing force of the abrasive grains has been the greatest problem to date. In order to cope with this problem by increasing the hardness of the resin bond layer, it is possible to increase the holding power of the abrasive grains, but the dropout of the abrasive grains due to a decrease in bendability becomes a new problem. .

[0010] In addition, the fixed abrasive type, including the wire saw described in the above-mentioned publication, forms a resin bond layer having a uniform thickness over the entire length of the core wire on the entire cross section around the core wire. Basic. For this reason, the wire saw has a uniform size cross-sectional shape of the core wire and the hard resin bond layer around the core wire at any part of the entire length. Therefore, the continuous sections in the length direction of the core wire have a relationship of reinforcing each other, and even if an attempt is made to cope by slightly lowering the hardness while maintaining the abrasive grain holding force of the resin bond layer to a certain extent, it is necessary to improve the bendability. Not valid.

As described above, in the conventional fixed-abrasive type wire saw using a resin bond, if the resin bond layer is hardened to increase the holding power of the abrasive grains, the bendability of the wire saw deteriorates and the grinding is rather performed. There is a problem that the grains fall off.

An object of the present invention is to provide a resin-bonded wire saw capable of holding abrasive grains stably without impairing the bendability of the core wire and further improving the cutting efficiency.

[0013]

The resin bond wire saw according to the present invention comprises a resin containing abrasive grains and a filler material for strengthening and hardening, which is formed in a segment-like shape at intervals in the axial direction of the core wire. Characterized in that the chip is integrally joined to the core wire.

Further, a resin containing abrasive grains and a filler agent for increasing strength and hardness is integrally bonded to the peripheral surface of the core wire to form a resin bond layer containing the abrasive grains. It is also possible to have a configuration having an outer shell in which a large diameter portion and a small diameter portion are sequentially formed in the axial direction of the core wire, and the large diameter portion is used as a chip for cutting.

In such a configuration, the resin can be a liquid polymer. In this case, if the addition amount of the filler is 5 to 50% by volume or the concentration of the abrasive grains is 150 to 200, the strength and hardness are further increased.

[0016]

1 is a schematic front view of a resin bond wire saw according to an embodiment of the present invention, in which a part thereof is viewed from a direction parallel to a core wire, and FIG.
It is a longitudinal cross-sectional view by the arrow A line.

As shown in FIG. 1, the resin bond wire saw of the present invention comprises a core wire 1 and a chip 2 integrally joined to the core wire 1 at a constant pitch.

The core wire 1 is, for example, a brass-plated piano wire, a special alloy steel wire, an ultra-high-strength alloy wire, or the like, which is generally used in a conventional wire saw. The core wire 1 has a wire diameter of about 0.10 to 0.60 mm, and has such an elasticity that the core wire 1 flexes and bends flexibly when running while being pressed against a work or when being wound around a pulley.

The tip 2 has an outer diameter of 0.20 to 1.00.
mm and the axis length is 1.0 to 2.0 mm
Both ends in the axial direction are tapered portions 2a that converge on the peripheral surface side of the core wire 1 respectively. As shown in FIG. 2, the chip 2 has a liquid resin 2b mixed with a filler 2c to hold abrasive grains 2d.
The abrasive grains 2d are diamond, CBN, GC, WA, or the like, similarly to a conventional wire saw.

As the liquid resin 2b, a thermosetting resin, a thermoplastic resin, a room temperature curable resin, an ultraviolet curable resin, or the like can be used, and the emphasis is placed on accurately controlling the layer thickness of the abrasive grains 2d. If so, it is preferable to use an ultraviolet-curable resin. The type of the UV-curable resin is not particularly limited as long as it is a resin (compound) having a reactive group (cross-linking portion) excited by a photoradical generator. For example, acrylic, epoxy, and aryl resins Etc. can be used.

As the filler 2c, GC, WA, F
All materials used in resin diamond wheels, such as e, Sn, W, WC, Ag, etc., can be used. Then, by adding the filler 2c to the liquid resin 2b, the abrasive grains are firmly held to achieve high strength and high hardness.

By using the liquid resin 2b in this manner, the resin ratio (volume ratio) in the chip 2 can be reduced and the ratio (volume ratio) between the filler 2c and the abrasive grains 2d can be increased. In the present invention, the addition amount of the filler agent 2c is 5 to 5.
50 (% by volume), and if the amount is within this range, the bending strength can be appropriately increased.

FIG. 3 is a characteristic diagram showing the relationship between the amount of filler 2c added and the bending strength (relative ratio) obtained by a test using a test piece. The test was conducted according to JIS K 7203 (1
982), which is a 40 mm × 7 mm rectangle having a thickness of 4 m
The test was performed at n = 4 using m test pieces. As can be seen from the characteristic diagram, the bending strength increases almost linearly when the amount of the filler 2c added exceeds 5 (vol%),
When the value is slightly smaller than the addition amount of 50 (vol%), the peak is reached, and when the addition amount is further increased, the bending strength sharply decreases. Therefore, it can be seen that the bending strength is improved in the range of the addition amount of 5 to 50 (vol%) as compared with the case where the filler is not included.

FIG. 4 is a characteristic diagram obtained by testing the relationship between the amount of the filler 2c added and the hardness (relative ratio). In this test, the same test piece as that used in the bending strength test shown in FIG. 3 was used, and the overall hardness of the test piece was measured by a Rockwell hardness tester. The characteristic diagram shown in FIG. 4 is based on the average value data of the overall hardness. When the addition amount of the filler 2c exceeds 10 (vol%), the hardness gradually increases, and when the addition amount exceeds 30 (vol%). It can be seen that the rate of increase in hardness is rapidly increasing. Therefore, particularly when the amount of the filler 2c added is 30 (% by volume) or more, the hardness is greatly improved, the holding power of the abrasive grains 2d can be increased, and the peeling thereof can be suppressed.

In view of the relationship between the bending strength in FIG. 3 and the hardness of FIG. 4, the addition amount of the filler 2c is 30 to 50 (in order to remarkably increase both the bending strength and the hardness. (% By volume).
Moreover, the addition amount of the filler agent 2c is 10 to 30 (vol%).
As described above, the desired purpose can be sufficiently achieved by setting the addition amount of the filler 2c to 10 to 50 (% by volume) as described above.

The tip 2 having high bending strength can also be obtained by setting the degree of concentration of the abrasive grains 2d to be much higher than that of a conventional resin-bonded grindstone, and by using the abrasive grains 2d themselves as a filler. FIG. 5 is a characteristic diagram obtained by an experiment showing the relationship between the degree of concentration and the bending strength (relative ratio) of the abrasive grains 2d.
It can be seen that up to 4 times the bending strength can be obtained.

Here, the addition amount of the filler 2c is set to 40 to
When it is 50 (% by volume), both the bending strength and the hardness can be maintained high as is clear from FIGS. Therefore, even if the degree of concentration of the abrasive grains 2 d is reduced to about 50, the amount of the filler 2 c added is 40 to 50 (vol%).
If it is set to a degree, the bending strength and the hardness can be properly maintained.
In addition, even when the concentration of the abrasive grains 2d is increased to nearly 200 and the filler 2c is not added at all, the bending strength is kept high. By appropriately setting the relationship between the added amount of the filler 2c and the degree of concentration of the abrasive grains 2d in this manner, it is possible to compensate for the bending strength and the hardness and to operate so as to obtain a high value.

FIG. 6 is a schematic view showing a production example of the resin bond wire saw shown in FIG. 1 and FIG.

In this production example, it is most efficient to use a resin in which the resin bond layer 11 is formed on the core wire 1 using an ultraviolet-curable resin as a binder. A cleaning chamber 22 for removing the resin layer is provided. The interval between the ultraviolet irradiation chamber 21 and the cleaning chamber 22 is made equal to the pitch of the chip 2 of the resin bond wire saw to be manufactured.

The ultraviolet irradiation chamber 21 has a built-in ultraviolet lamp, and irradiates the integrated product of the core wire 1 and the resin bond layer 11 inserted from the upstream of the line with ultraviolet light. Further, the cleaning chamber 22 includes the uncured resin bond layer 11.
Is eluted and removed, and contains acetone, ethyl acetate, chloroform, ether, methanol, ethanol, tetrahydrofuran, dimethylsulfoxide and the like as a washing solution.

The strip-shaped material as an integral product of the core wire 1 and the resin bond layer 11 is intermittently fed from left to right in FIG. The feed pitch at this time is equal to the distance from the entrance of the ultraviolet irradiation chamber 21 to the entrance of the cleaning chamber 22, and the ultraviolet lamp in the ultraviolet irradiation chamber 21 is turned on only during the period when the feed is stopped.
By such feeding and the operation of turning on the ultraviolet lamp,
As shown in the drawing, during the period in which the feeding is stopped, the resin bond layer 11 containing the UV-curable resin is hardened into a hardened portion with respect to the material of the portion located in the UV-irradiation chamber 21. 21 and cleaning chamber 2
2 remains as uncured portions. Then, after a certain period of time, it will be sent for the previous pitch,
The uncured part and the cured part move into the cleaning chamber 22,
The subsequent portion also advances to the inside of the ultraviolet irradiation chamber 21 and the entrance portion of the cleaning chamber 22 ahead. In the cleaning chamber 22, the uncured portion is eluted and removed, and the core wire 1 is exposed.

By the above operation, the material is intermittently sent from the ultraviolet irradiation chamber 22 to the cleaning chamber 23, and when it comes out of the cleaning chamber 22, the resin in which the chips 2 are formed at regular intervals on the core wire 1 is formed. A bond wire saw is obtained.

In the resin bond wire saw in which the chips 2 are formed at regular intervals on the core wire 1 as described above, the core wire 1 has a smaller length than the conventional case where the entire length of the core wire is covered with the resin bond.
The bendability of the workpiece is not impaired, and the workability of the workpiece is improved. Moreover, since the bending strength and hardness of the chip 2 are increased by adding an appropriate amount of the filler 2c to the liquid resin 2b, deformation and abrasion thereof are suppressed. And abrasive grains 2d
The bending strength can be improved and the abrasion resistance can be further improved by increasing the degree of concentration of the abrasive grains 2d and causing the abrasive grains 2d to act in the same manner as the filler material 2c. That is, high-efficiency cutting by the chip can be performed while maintaining the flexibility of the resin bond wire saw, and cracks do not occur in the chip 2, so that the life thereof is greatly improved.

FIG. 7 shows another example of the resin bond wire saw, and is a partial front view of a part of the resin bond wire saw viewed from a direction parallel to the core wire as in FIG.

As shown in the figure, a resin bond layer 3 containing abrasive grains and a filler is formed on the core wire 1 over its entire length. The resin bond layer 3 has a large diameter portion, a small diameter portion, and a tapered portion therebetween formed in this order. The large diameter portion is a chip 3a, and both ends thereof are tapered portions 3b as in the previous example. Things.

The resin bond layer 3 in the example of FIG. 7 is a mixture of liquid resin and abrasive grains containing copper, GC, WA, or the like as a filler, similarly to the chip 2 of the previous example. It is a type. The cross-sectional shape of the tip 3a is almost the same as that shown in FIG. 2, and the amount of the filler added is 5 to 50% by volume and the concentration of the abrasive grains is about 150 to 200 as described above. .

As described above, the resin bond layer 3 around the core wire 1
The large-diameter portion is used as the chip 3a, so that the bendability of the core wire 1 is secured in a portion where the layer thickness between the chips 3a is small, and the occurrence of cracks in the resin bond layer 3 is suppressed. Therefore, the workability with respect to the work can be kept good, and the life can be improved. Then, similarly to the previous example, the wear resistance is improved by the high strength and high hardness by optimizing the amount of the filler contained in the resin bond layer 3 and the degree of concentration of the abrasive grains, thereby improving the cutting efficiency and the life. Further improvements are obtained.

[0038]

According to the first and second aspects of the present invention, the core wire can be sufficiently bent, so that the workability of the work can be kept good, and at the same time, the generation of cracks in the chip can be prevented. In addition, since the supply of the grinding fluid to the inner surface of the work can be performed promptly, heat generation during cutting can be reduced, and deformation of the work due to residual thermal stress can be prevented. Further, since a filler agent for increasing the strength and hardness is included in the resin, the wear resistance is improved and the life can be extended.

According to the third aspect of the present invention, the volume ratio of the abrasive grains and the filler agent can be made higher than the volume ratio of the resin.
The strength and hardness of the chip are further improved, and the cutting efficiency and the life can be further improved.

According to the fourth aspect of the present invention, by optimizing the amount of the filler added, the strength and hardness of the chip are further promoted, and the cutting efficiency and the life are greatly improved.

According to the fifth aspect of the present invention, by optimizing the degree of concentration of the abrasive grains, the same effect as that of the filler can be obtained, so that the chip can be made to have high strength and high hardness to the maximum. A wire saw with high wear resistance and long life can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a part of a resin bond wire saw according to an embodiment of the present invention, as viewed from a direction parallel to a core wire.

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

FIG. 3 is a characteristic diagram showing the relationship between the amount of filler added and the flexural strength.

FIG. 4 is a characteristic diagram showing the relationship between the amount of filler added and hardness.

FIG. 5 is a characteristic diagram showing the relationship between the degree of concentration of abrasive grains and bending strength.

FIG. 6 is a schematic view showing a manufacturing process of the resin bond wire saw of FIG.

FIG. 7 is a schematic view of a resin bond wire saw according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 core wire 2 chip 2a taper portion 2b liquid resin 2c filler agent 2d abrasive grains 3 resin bond layer 3a chip 3b taper portion 11 resin bond layer 21 ultraviolet irradiation chamber 22 cleaning chamber

Claims (5)

[Claims] 1. A resin containing abrasive grains and a filler material for increasing strength and hardness is integrally joined to the core wire as a segmented chip at intervals in the axial direction of the core wire. Resin bond wire saw. 2. A resin containing abrasive grains and a filler agent for increasing strength and hardness is integrally joined to a peripheral surface of a core wire to form a resin bond layer containing the abrasive grains, wherein the resin bond layer is A resin bond wire saw having an outer shell in which a large diameter portion and a small diameter portion are sequentially formed in the axial direction of the core wire, wherein the large diameter portion is used as a cutting tip. 3. The resin bond wire saw according to claim 1, wherein the resin is a liquid polymer. 4. The resin bond wire saw according to claim 3, wherein the amount of the filler added is 5 to 50% by volume. 5. The resin bond wire saw according to claim 3, wherein the degree of concentration of the abrasive grains is 150 to 200.