TW201350270A - Adhesive composition for resin-bonded wire saw and method for producing resin-bonded wire saw - Google Patents

Abstract

To provide: a method for efficiently producing a resin-bonded wire saw that stabilizes the step of cutting an ingot and that obtains a smooth wafer in which the thickness of a damaged layer on the wafer surface caused by cutting is small; and an adhesive composition for resin-bonded wire saws that is suitable for said method. This method for producing a resin-bonded wire saw comprises: a step of applying, to the surface of a metal core wire, a paste including an adhesive composition, abrasive grains, and a solvent for dissolving the adhesive composition, said adhesive composition being used for producing resin-bonded wire saws in which abrasive grains are firmly fixed to the surface of a metal core wire by means of a resin bond, said adhesive composition for resin-bonded wire saws including, as essential components, 100 parts by weight of a novolac-type phenolic resin, 10-30 parts by weight of a resol-type phenolic resin, and 0.1-5 parts by weight of an amine-based silane coupling agent; and a heating step of heating the applied paste with infrared rays including near-infrared rays, and causing said adhesive composition to undergo a cross-linking reaction.

Description

Adhesive composition for resin bonded wire saw and method for manufacturing resin bonded wire saw

The present invention relates to a solar cell/electronic substrate represented by a wafer obtained by slicing a large-diameter twin ingot, a compound semiconductor substrate such as gallium arsenide or a magnet, crystal, or glass. Fixed abrasive grain saws for cutting magnetic/optical substrates, etc., in particular, for a fixed abrasive grain saw, especially a resin bonded wire saw, which is suitable for fine cutting of harder and brittle materials. A method for producing a wire saw obtained by fixing abrasive grains on a wire, and an adhesive composition used in the production method.

It has been pointed out that in the cutting of TFTs for thin-film (Thin Film Transistor) or solar cell applications, the previously used inner blade grinding wheel (ID blade, inner diameter blade, inner diameter) The blade has problems such as reduction in processing efficiency or productivity, generation of a deteriorated layer, reduction in cutting dimensional accuracy, and the like, and a large-sized device. Therefore, cutting processing using a wire saw has been actively carried out in recent years. The wire saw performs a cutting operation by pressing a wire together with the abrasive grains for cutting while being pressed against the object to be cut. The cutting process using the wire saw is easy to cope with the large diameter of the twin ingot, and it is possible to simultaneously produce a plurality of wafers of a plurality of wafers, unlike the inner diameter grinding stone obtained by cutting only one wafer from the ingot.

The wire saw used in such a cutting process has a free abrasive grain type and a fixed abrasive grain type. In the free abrasive grain type, the piano line is used as the core material. The cloth is used by dispersing fine abrasive grains such as diamond or tantalum carbide in an aqueous slurry or oil to form an abrasive liquid. In this case, the cutting process is performed while the tension is applied to the wire coated with the abrasive liquid, and the cutting process is performed (for example, refer to Patent Document 1). As a result, the cutting is performed slowly by the abrasive grains interposed in the gap between the wire and the workpiece.

However, in this method, it is necessary to continuously supply an appropriate amount of abrasive grains to the cutting interface, in particular, the viscosity of the slurry or the oil is subtly changed due to temperature, etc., and as a result, thickness unevenness or undulation is related to the quality of the wafer. The management is particularly difficult. Further, in this method, since the abrasive grains are freely moved during the dicing of the wafer, not only the wafer but also the wire is rubbed, and there is a limit in reducing the wire diameter without being broken. Further, it has been pointed out that the wafer surface is polished by the abrasive grains that are freely moved, so that a thick processed metamorphic layer (damage layer) related to the photoelectric-electric conversion efficiency is formed.

As a method for solving such a problem, a fixed abrasive grain type wire saw in which diamond or the like is fixed on a wire is proposed. The method of fixing the diamond includes a resin binder method, a plating method, and the like.

The plating method is a method of fixing diamond to a piano wire by nickel plating or the like (for example, refer to Patent Documents 2 and 3). This method is a method in which nickel is deposited on a surface of a piano wire while nickel is deposited on a surface of a piano wire to firmly fix it, and a strong fixing force is excellent in terms of cutting of the ingot. However, the wire diameter gradually becomes thicker in the nickel plating step.

Further, in this method, it is desired that the diamond is deeply embedded in the plating layer and physically fixed, and the fixing force of the diamond is governed by the amount of deposition of the plating film, which causes problems such as poor productivity and high cost. Furthermore, It is considered that the wire diameter of the wire is thickened by nickel, and therefore, when the long wire is repeatedly wound up on a pulley, the wire is liable to cause fatigue fracture.

Further, a fixed abrasive grain type wire saw is disclosed, which is characterized in that a metal layer is formed on a wire by a thickness of 5 to 40% of a diameter of diamond (abrasive grain), solder, or the like, and a molten state is formed in the metal layer. The above diamond is adhered and cured (for example, refer to Patent Document 4). In this method, when the melting point of the solder or the like constituting the metal layer is high, the wire is excessively heated by the melting of the metal layer, and annealing of the wire occurs, and the possibility that the tensile strength of the wire is lowered is high, and the selection of the wire material is high. It has become difficult. For example, it is not possible to use a piano wire or a hard steel wire whose hardness or tensile strength is lowered by annealing of a core wire at a relatively low temperature as a core wire, instead of using a stainless steel wire or failing to embed due to embrittlement A tungsten wire bent but having the same tensile strength. On the other hand, when the melting point of the solder or the like constituting the metal layer is low, heat is generated by friction during the cutting process of the workpiece of the wire saw, and the metal layer is melted, and the abrasive grains are easily detached from the wire.

In the resin adhesive method, a resin adhesive such as a phenol resin or a mixture of abrasive particles such as diamond is applied to a piano wire by a floating mold or the like, and a heat treatment is performed using a crucible furnace (see Patent Document 4). Thereby, the diamond is fixed by the hardened resin (for example, refer to Patent Documents 5, 6, and 7). As the simmering furnace, a hot air drying method is known (for example, refer to Patent Documents 8 and 9). The resin binder method is suitable for making a relatively inexpensive and long wire saw. Further, since the vibration of the wire generated in the ingot dicing is absorbed by the soft resin such as a phenol resin or the like, the wire saw can be driven at a high speed during the cutting of the ingot, and can be stabilized at a high speed. It Cutting. Also, a thinner wafer can be obtained. On the other hand, some people have pointed out the following disadvantages: due to the low retention of the resin, the diamond is continuously detached during cutting, which tends to cause a decrease in sharpness or a thinner diameter, and has a short life. Further, when a thermosetting resin adhesive is used, the curing cannot be performed in a short time, and if it is carried out at a high temperature, there is a problem that foaming or the like is caused by decomposition of a curing agent or a volatile component accompanying the reaction. There is a problem that the speed of wire saw manufacturing cannot be increased.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2008-103690

Patent Document 2: Japanese Patent Special Fair No. 4-4105

Patent Document 3: Japanese Patent Laid-Open Publication No. 2003-334763

Patent Document 4: Japanese Patent Laid-Open No. 2006-123024

Patent Document 5: Japanese Patent Laid-Open Publication No. 2000-263452

Patent Document 6: Japanese Patent Laid-Open Publication No. 2000-271872

Patent Document 7: Japanese Patent Re-Patent Patent WO 98/35784

Patent Document 8: Japanese Patent Laid-Open Publication No. H09-35556

Patent Document 9: Japanese Patent Laid-Open Publication No. 2010-267533

It is an object of the present invention to provide a stability of an ingot cutting step of a resin bonded wire saw, thereby obtaining a thickness of a damaged layer (damage layer) of a wafer surface caused by ingot cutting and thickness unevenness. Long-life resin bonded wire saw with few smooth wafers, and high-efficiency resin adhesive The manufacturing method of the wire saw. Further, it is an object of the present invention to provide a novel adhesive composition for a resin bonded wire saw suitable for the method.

The inventors of the present invention have made intensive studies to solve the above problems, and as a result, it has been found that a resol type phenol resin and a novolak type phenol resin are combined as a binder at a specific ratio. And a composition system which is thermally hardened by infrared heating in a short time, and it is found that it is possible to efficiently manufacture a wafer having a small thickness and a smooth thickness of the damaged wafer surface due to the dicing. Further, the long-life resin-bonded wire saw with less peeling of the diamond abrasive grains is completed, thereby completing the present invention.

The main purpose of the present invention is to provide an adhesive composition for a resin bonded wire saw, which is used in the manufacture of a resin bonded wire saw in which a surface of a metal core wire is fixed with a resin for an adhesive for an adhesive, and It is an essential ingredient.

The adhesive composition may further contain 5 to 20 parts by weight of a curing agent of a novolac type phenol resin.

Further, the present invention is directed to a slurry for a resin-bonded wire saw comprising the above-described adhesive composition, a solvent of the adhesive composition, abrasive grains, and a filler containing inorganic particles.

Further, the present invention is directed to a method of manufacturing a resin bonded wire saw, comprising the steps of: preparing the slurry and the metal core, applying the slurry to the surface of the metal core, and including near infrared rays; The infrared heating heats the coated slurry to cause a heating step of crosslinking reaction of the above-mentioned adhesive composition.

The method for producing the resin bonded wire saw may further include the steps of: winding the wire obtained in the heating step to obtain a wound body, and heating the reheating step of the wound body.

According to the present invention, there is provided a wafer which is efficiently manufactured by cutting a plurality of wafers, such as uneven wafer thickness, variation in thickness in the wafer, unevenness in thickness deviation, and wafer cutting A method in which the damaged layer of the surface is thin and the long-life resin is bonded to the wire saw. Further, an adhesive composition for a resin bonded wire saw suitable for the method is provided.

The adhesive composition of the present invention is used for a resin-bonded wire saw in the manufacture of a resin-bonded wire saw in which a surface of a metal core wire (hereinafter also referred to as a core wire) is fixed with a resin binder (resin adhesive). Adhesive composition, and It is an essential ingredient.

The novolak-type phenol-based resin is a resin obtained by condensing a phenol compound such as phenol, cresol or bisphenol A with an aldehyde such as formaldehyde in the presence of an acid catalyst. The resol type phenol-based resin is obtained by condensing a phenol compound such as phenol, cresol or bisphenol A with an aldehyde such as formaldehyde with a basic catalyst.

The adhesive composition of the present invention may further contain a curing agent for a novolac type phenol resin. It is preferable to contain 5 to 20 parts by weight of the curing agent of the novolac type phenol resin with respect to 100 parts by weight of the novolac type phenol resin.

In the case where the adhesive composition of the present invention contains a curing agent of a novolak-type phenol-based resin, if the compounding ratio of the curing agent exceeds 20 parts by weight based on 100 parts by weight of the novolak-type phenol-based resin, there is a hardener. The gas generated by decomposition causes expansion or cracking of the cured resin. In addition, when the blending ratio of the curing agent is less than 5 parts by weight based on 100 parts by weight of the novolak-type phenol-based resin, the curing ratio of the novolak-type phenol-based resin is small, and the curing of the novolak resin is insufficient. The situation. In this case, a suitable resol-type phenol-based resin may be appropriately added. Further, it is preferable to adjust the amount of the curing agent of the novolak-type phenol-based resin to the blending amount of the novolac type phenol-based resin. The setting is appropriately performed within the range of (5 to 20 parts by weight).

Examples of the curing agent of the novolac type phenol resin include cyclohexamethylenetetramine, methylol melamine, and methylol urea. Among them, cyclohexamethylenetetramine is preferred in that the hardening time of the resin is short.

The adhesive composition of the present invention may further contain, for example, 5 to 15 parts by weight of a phenolic compound such as phenol, cresol or bisphenol A. Further, a plurality of (for example, 1 part by weight or less) aldehyde such as formaldehyde may be contained. Further, as long as a small amount, it may also contain alkaline Catalyst or moisture.

The adhesive composition for a resin-bonded wire saw of the present invention can be crosslinked by a phenol-based resin by containing 10 to 30 parts by weight of a novolac type phenol resin per 100 parts by weight of the novolak-type phenol resin. A dense three-dimensional network structure is obtained. Thereby, a firm engagement with the abrasive particles can be achieved. When the resol type phenol-based resin is more than 30 parts by weight based on 100 parts by weight of the novolak-type phenol-based resin, the viscosity of the following paste becomes low. Therefore, when the resol type phenol-based resin is larger than 30 parts by weight based on 100 parts by weight of the novolak-type phenol-based resin, the viscosity suitable for coating the slurry at a high speed for the core wire cannot be obtained. When the resol type phenol-based resin is less than 10 parts by weight based on 100 parts by weight of the novolac type phenol-based resin, the crosslinking rate of the adhesive composition becomes slow. Therefore, when the resol type phenol-based resin is less than 10 parts by weight based on 100 parts by weight of the novolak-type phenol-based resin, it is difficult to harden the slurry in a short time while moving the core wire, and it is not possible to perform high speed. Production of high performance resin bonded wire saws. It is more preferable to appropriately add a curing agent of a novolak-type phenol-based resin in the above ratio to harden the slurry in a short time.

In the adhesive composition for a resin-bonded wire saw of the present invention, 0.1 to 5 parts by weight of an amine-based decane coupling agent is blended with 100 parts by weight of the novolak-type phenol-based resin, and the abrasive grains and the core and the adhesive are followed. The strength increases. When the compounding ratio of the amine decane coupling agent is less than 0.1 part by weight based on 100 parts by weight of the novolac type phenol resin, sufficient adhesion between the phenol resin and the abrasive grains coated with nickel cannot be obtained. In this case, an adhesive composition in which an amine decane coupling agent is formulated at the above-mentioned compounding ratio is used. Compared with the resin-bonded wire saw manufactured, the resin-bonded wire saw has a poor cutting ability. When the blending ratio of the amine-based decane coupling agent is more than 5 parts by weight based on 100 parts by weight of the novolak-type phenol-based resin, the generation of bubbles due to thermal decomposition is caused, or the curing of the novolak-type phenol-based resin is affected. A sufficient adhesion force cannot be obtained between the phenol resin and the abrasive grains. In this case, the cutting ability of the resin bonded wire saw becomes small.

As the amine decane coupling agent, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxydecane, N-2- can be exemplified. (Aminoethyl)-3-aminopropylmethyldimethoxydecane, 3-aminopropyltriethoxydecane, and the like.

A method for producing a resin bonded wire saw using the adhesive composition of the present invention comprises a method of producing a resin bonded wire saw comprising the steps of: preparing an adhesive composition as described above, dissolving the adhesive composition, and adjusting a slurry viscosity. a step of preparing a slurry of the solvent, the abrasive particles, and the filler containing the inorganic particles, further preparing a metal core wire, applying the slurry to the surface of the metal core wire, and heating the coated slurry with infrared rays Further, the above-mentioned adhesive composition is subjected to a heating step in which a crosslinking reaction accompanying dehydration occurs.

By this heating step, the dehydration condensation of the adhesive composition proceeds rapidly to form a dense three-dimensional crosslinked structure.

When the slurry is applied to the traveling core wire, for example, it is continuously applied to the metal core wire by a dispenser (syringe) method or a floating mold method in which the slurry is extruded from a fine-diameter nozzle and applied to a core wire. surface. The coating amount of the slurry is preferably The concentration of the abrasive grains is set in a manner of 50 to 120. The degree of concentration is a value obtained by taking the ratio of the area of the abrasive grain to the projected area of the outer surface of the wire saw as an index. In the present specification, the degree of concentration is set to 100 when the projected area of the abrasive grain accounts for 15% of the total projected area. For example, it is considered that the degree of concentration of the projected area of the abrasive grains is 200% when the projected area is 30% of the total projected area, and the degree of concentration is 50 when the projected area of the abrasive grains accounts for 7.5% of the total projected area.

When the slurry is continuously applied to the traveling core wire, the viscosity of the slurry is adjusted to 3 to 6 Pa by adding a solvent to the adhesive composition. s, which is preferred in obtaining an appropriate and uniform coating amount. For example, the solvent is preferably set in the range of 100 to 200 parts by weight based on 100 parts by weight of the adhesive composition. The solvent for adjusting the viscosity of the slurry is not particularly limited, and is preferably a low-boiling o-cresol in the ortho, meta-, and isomers.

The abrasive grains to be used in the present invention are not particularly limited as long as they are abrasive grains for fixing the abrasive granulator, and examples thereof include diamond abrasive grains, cubic BN abrasive grains, alumina abrasive grains, and cerium carbide abrasive grains. Wait.

In particular, since the diamond abrasive grains have extremely high thermal conductivity, the portion irradiated to the abrasive grains is rapidly heated in a short period of heating. Thereby, it is preferable to use diamond abrasive grains in terms of the rapid progress of the chemical reaction related to uniform fixation. The size of the abrasive grains is selected depending on the purpose or according to the diameter of the core wire, but it is preferably several micrometers to 25 micrometers in terms of cutting of the twin crystal ingot having a small kerf loss (cutting margin). Further, as the abrasive grains used in the present invention, it is also possible to remove copper (in the case where copper remains as an impurity, a deeper energy level is formed in the band gap of the crucible in the heat treatment step, so that it is used as a solar cell. When the power generation efficiency is lowered, the metal coated with gold such as nickel or titanium Gangshi. In the case of using nickel-coated diamond, the resin-bonded wire saw obtained by the present invention can achieve warpage or saw mark comparison as compared with a diamond-grain-fixed wire saw using nickel or the like. The slicing of wafers with few extremely smooth surfaces.

In order to avoid clogging caused by swarf generated during slicing, the abrasive granules must be appropriately dispersed and fixed on the core wire in accordance with the above-mentioned criteria called concentration. Further, in the present invention, the abrasive grains are preferably blended in an amount of 50 to 120 parts by weight based on 100 parts by weight of the adhesive composition.

As the core wire used in the present invention, a steel wire is preferably used. The wire diameter is not particularly limited, and is preferably 0.3 to 0.05 mm. The steel wire can be exemplified by wires of heat-treated spring steel such as high carbon steel or medium carbon low alloy steel, wires of processed spring steel such as hard steel wire, piano wire or stainless steel wire, cold rolled steel wire or oil tempered steel wire, and low alloy. High-toughness/high fatigue strength steel wire such as steel, medium alloy steel or high alloy steel, and aging steel.

The slurry is continuously applied to the traveling core wire, and the core wire coated with the slurry is continuously heated while being heated, whereby the applied slurry is cured by heating. This heating is performed by irradiating the applied slurry with infrared rays. When the hot air is heated by the previous crucible or the like, the slurry is thermally hardened from the outer surface to form a skin film, and the water formed by the dehydration reaction is sealed inside, and the gas is easily generated in the gasification adhesive. bubble. On the other hand, when the slurry is heated by infrared rays using a lamp or the like, the near-infrared rays having a wavelength of about 1 μm are preferably absorbed by the water efficiency, so that the dehydration reaction is carried out in a short time to complete the crosslinking polymerization. Further, since the water is excited and evaporates in a short time, foaming is less likely to occur in the adhesive. The infrared ray is preferably a wave The near-infrared band with a length of 0.7 to 2.5 μm has one or a plurality of spectral peaks. Among them, it is preferred to promote the dehydration and crosslinking of the adhesive composition and to suppress the foaming of the adhesive accompanying the gasification of the water formed by the dehydration reaction, and to prevent the foaming of the adhesive after curing. It is a near-infrared heating with a wavelength of about 1 μm (in the range of 0.9 to 1.3 μm).

As a method of heating the coated slurry by infrared rays during the progress of the core wire coated with the slurry, a mode as shown in FIG. 1 can be cited. In this embodiment, a half cylinder type concave mirror 2 and an infrared ray emitting body 4 are used. In this manner, the semi-cylindrical concave mirror 2 is arranged such that the core wire 3 coated with the slurry travels in the longitudinal direction of the concave mirror 2 (in the direction orthogonal to the plane of the drawing), while being parallelized The emitted light of the illuminant 4 arranged linearly in the longitudinal direction of the concave mirror 2 is condensed toward the traveling path of the core wire to be about 10 mm. The size. Symbol 8 is a reflecting surface of the concave mirror 2. The concave mirror 2 and the illuminator 4 may also be formed in pairs, and a plurality of the mirrors 2 may be arranged in combination with each other in a symmetrical center. It is preferable to use an infrared lamp as the luminous body 4 for effective heating in a short time. The temperature of the concentrating portion 6 is measured by a sheath type thermocouple of 1.0 mm diameter, preferably 500 to 800 °C. The length of the concentrating portion 6 is determined by the size or number of the illuminator 4 or the concave mirror 2. By using the concentrating portion 6 as a heating region, the applied slurry can be heated by infrared rays during the progress of the core wire coated with the slurry. The heating zone can be constructed using an infrared lamp. In the case of using an infrared lamp, the length of the concentrating portion 6 can be set, for example, to 400 to 1000 mm. The heating region may be formed by arranging a plurality of infrared lamps in series in the traveling direction of the core wire.

As the illuminant 4, it is preferably used in the band of near-infrared rays. Infrared lamp with the peak of the light spectrum. Preferred examples of the infrared lamp include a short-arc Xenon lamp or a rod-shaped lamp in which a tungsten wire is sealed in a quartz glass tube.

In the present invention, by the heating method, the core wire coated with the slurry can be hardened by the adhesive in a short time without foaming the adhesive at a high speed of 1000 to 2000 mm/sec. .

Further, a filler containing inorganic particles is blended in the slurry. It is preferred to formulate 20 to 100 parts by weight of the filler with respect to 100 parts by weight of the adhesive composition. Further, it is preferably formulated in an amount of 30 to 60 parts by weight of the filler. As the filler, fine particles (about 2 to 3 μm) of diamond can be used, and inorganic materials having various shapes or hardness can be used. As an example, tantalum carbide particles are used. The mixing of the filler has an effect of suppressing thermal expansion and contraction of the resin to reduce the shedding of the abrasive grains in the ingot cutting.

In the present invention, a resin-bonded wire saw having more stable performance can be obtained by reheating a wire heated by the above infrared heating (a core wire coated with a slurry). This reheating is performed in order to remove the thermal strain received by the resin layer or the core wire which is repeatedly expanded and contracted by the short-time hardening by the infrared heating described above. In the infrared heating described above, in a state where the adhesive is not completely cured, the wire (the core wire coated with the slurry) is wound on the bobbin with a constant tension, for example, about 10 N, to reheat the wound body. At the time, the lines are stuck to each other and cannot be defibrated, or the fiber is peeled off, and the adhesive is peeled off. Therefore, it is preferred in principle that the hardening of the adhesive composition is substantially completed in the infrared heating.

The reheating is preferably carried out at 100 to 200 ° C for 1 to 5 hours. Again, even if Since it takes time to reheat, and a plurality of coiled bodies can be collectively processed at the same time by reheating, the productivity of the resin-bonded wire saw as a whole is not greatly reduced as a whole. As described above, in the present invention, production can be efficiently carried out by combining high-speed heating of the wire with reheating of the coiled body, and the productivity of the resin bonded wire saw can be improved.

Previously, in the reheating method of such a coiled body, when the heating wire (the core wire coated with the slurry) was driven at a high speed, when the wire was reheated, the wires were stuck to each other and could not be defibrated or barely defibrated. Then the agent is peeled off and the like. However, in the present invention, by using the above-mentioned adhesive composition and heating by near-infrared rays, the wire can be heated at a high speed without causing foaming, and the hardening of the adhesive composition is substantially completely performed. Therefore, in the present invention, thermal strain grease removal can be performed by reheating without causing problems in which the wires are stuck to each other.

The resin bonded wire saw obtained by the present invention has a larger depth of cut than the resin bonded wire saw manufactured by the prior method. The depth of penetration refers to a depth of penetration when a workpiece of a specific shape is pressed against a wire saw and the wire saw is reciprocated and the wire saw is cut into the cut. The cutting of the wire saw at this time is mainly caused by the falling off of the abrasive grains. Therefore, it can be said that the fixing strength of the abrasive grains to the core wire in the resin-bonded wire saw obtained by the present invention is drastically improved, and is long-lived. Moreover, since the resin-bonded wire saw obtained by the present invention has high fixing strength to the core wire by the abrasive grains, even if a plurality of wafers are cut out, the thickness of the wafer is uneven, the thickness of the wafer varies, and the thickness varies. Any of the unevenness is also smaller than the resin bonded wire saw manufactured by the prior method. Further, using the resin obtained by the present invention A wire saw can be used to obtain a smooth wafer. Further, by using the resin bonded wire saw obtained by the present invention, a wafer having a thin surface with a damaged layer (damage layer) can be obtained. Further, according to the measurement result of the three-point bending stress of the wafer, since the starting point of the damage due to the processing of the deteriorated layer is small, a wafer having a high bending strength can be obtained.

Example

Using the adhesive composition for a resin-bonded wire saw having the composition shown below, the slurry was adjusted according to the blending ratio of the slurry shown below, and a resin-bonded wire saw was produced by the production line of the wire saw shown below.

[Example 1]

Formulation ratio of adhesive composition for resin bonded wire saw (Note: The blending amount of the novolac type phenol resin in the composition is 80 parts by weight × 0.86 = 68.8 parts by weight, and the blending amount of the novolac type phenol resin is 20 parts by weight × 0.80 = 16 parts by weight. In the first embodiment, when the ratio is 100 parts by weight based on 100 parts by weight of the novolak-type phenol resin, about 23.2 parts by weight of the resol type phenol-based resin is blended.

Slurry blending ratio

[Embodiment 2]

Formulation ratio of adhesive composition for resin bonded wire saw (Note: In the second embodiment, when the ratio is 100 parts by weight based on 100 parts by weight of the novolac type phenol resin, about 10.3 parts by weight of the resol type phenol resin is blended)

[Comparative Example 1]

Formulation ratio of adhesive composition for resin bonded wire saw (Note: In Comparative Example 1, when the ratio is 100 parts by weight based on 100 parts by weight of the novolac type phenol resin, about 7 parts by weight of the novolac type phenol resin is blended)

[Comparative Example 2]

Formulation ratio of adhesive composition for resin bonded wire saw (Note: In Comparative Example 2, when the ratio is 100 parts by weight based on 100 parts by weight of the novolak-type phenol resin, about 40 parts by weight of the resol type phenol-based resin is blended)

[Comparative Example 3]

Formulation ratio of adhesive composition for resin bonded wire saw

The lines used in the examples and comparative examples: 100 μm steel wire

Production line of wire saw in the examples and comparative examples

Core wire extractor: A normal extractor that takes out the core wire of the take-up shape.

Coating device: The slurry is uniformly applied to the surface of the core wire by a mold of a sprinkler shape.

Heating device: A device that heats a core wire coated with a slurry. As the apparatus, three gold image furnaces manufactured by ULVAC Technology Co., Ltd., which uses a rod-shaped lamp in which a tungsten wire is sealed in a quartz glass tube, are used: type RHL-E410-N (heating) The length is 265 mm and the maximum output is 4 kw). The energy splitting distribution of the rod lamp is shown in FIG.

Coiler: The usual coiler for coiling wire saws.

Reverberatory furnace: set temperature 725~750°C

Core travel speed: 1200 mm/sec

Coating amount of slurry: 0.01 g/m

Reheating furnace: a heating furnace that accommodates and heats a wire taken up by a coiler (with an adhesive, abrasive grains)

Heating in reheating furnace: 180 ° C × 2 hours

In Comparative Example 1, the curing rate of the adhesive composition was slow, and the curing of the adhesive composition was incomplete by the reverberatory furnace. After heating in the reheating furnace, the wires were stuck to each other and could not be defibrated. In Examples 1 and 2, after heating in a reheating furnace, the threads were not stuck to each other, and the defibration (winding back) was smoothly performed.

In Comparative Example 2, although the solvent for viscosity adjustment was not used, the viscosity of the slurry was as low as 2 Pa. S, the target coating amount (0.01 g/m) cannot be obtained (the traveling speed of the core wire: 1200 mm/sec).

The resin bonded wire saw (a1) obtained in Example 1 was obtained in Example 2. The cutting performance of the resin bonded wire saw (a2) was compared with a resin bonded wire saw (b1) using a photocurable resin as an adhesive and a resin bonded wire saw (b2) obtained in Comparative Example 3.

Cutting performance test

A 1 cm ³ polysilicon workpiece was placed below the horizontally stretched line, and the workpiece was moved down and cut to measure the depth of cut.

Cutting conditions

Line motion: reciprocating motion with an amplitude of 80 mm and a speed of 400 mm/min

Cutting time: until the line is broken

Falling speed of the workpiece: 0.9 mm/min

Table 1 shows the results of the cutting performance test.

According to Table 1, the following results were obtained: the depth of cut of the resin-bonded wire saws (a1) and (a2) obtained in Examples 1 and 2 and the resin-bonded wire saw (b1) using a photocurable resin, and the obtained in Comparative Example 3. The resin bonded wire saw (b2) is deeper.

Further, by using the cutting (A1) of the resin bonded wire saw (a1) obtained in Example 1, and using a wire saw using an electroplating method (abrasive grains: diamond grains plated with nickel, a core wire diameter of 100 μm) ( c) cutting (B), and the distribution of the thickness of the wafer and the variation of the thickness of the wafer (the difference between the maximum thickness and the minimum thickness) when the plurality of wafers are cut out from the twin ingot are shown in Fig. 3, respectively. In the chart of Figure 4. 3 and 4, the vertical axis is the number of wafers, the horizontal axis of FIG. 3 is the thickness of the wafer, and the horizontal axis of FIG. 4 is the variation of the thickness in the wafer.

Cutting conditions:

Device: Multi-wire saw device: Komatsu NTC type: PV500D

Wire saw wire speed: 1000 m/min

Cutting speed (cutting depth per line to the line cut into the twin ingot): 0.5 mm/min

Workpiece: polycrystalline germanium ingot, 156 mm square According to Fig. 3 and Fig. 4, it can be seen that if a resin bonded wire saw (a1) is used, a plurality of crystals are cut out compared with the case of using a wire saw (c) by electroplating. The unevenness of the thickness of the wafer during the round, the variation in the thickness of the wafer, and the variation in the thickness deviation are all reduced, and the quality can be stably produced.

Table 2 shows: cutting (A1) by using the resin-bonded wire saw (a1) obtained in Example 1, cutting (A2) using the resin-bonded wire saw (a2) obtained in Example 2, using electroplating Method wire saw [abrasive grain: diamond grain coated with nickel (particle size 10~20 μm)], core wire diameter 100 μm) (c) cutting (B), using free abrasive grain method (using SiC abrasive grain # 5000) cutting (C), and the wafer is based on the arithmetic mean surface roughness (Ra) and maximum height (Ry) of JIS B 0601 when the wafer is cut out from the wafer (corresponding to a pitch of 170 μm). The values in Table 2 are the average of the measured values at three points. Cutting conditions and the situation of Figure 3, Figure 4 The same shape.

According to Table 2, when a resin bonded wire saw (a1) or a resin bonded wire saw (a2) is used, a smooth wafer can be obtained as compared with cutting by a plating method or cutting by a free abrasive grain method.

Next, regarding the damage layer (machining layer) of the wafer surface cut by the cutting (A1), the cutting (A2), the cutting (B), and the cutting (C) under the same conditions as those in Table 2 The thickness was observed using a SEM (Scanning Electron Microscope) cross section, and the measurement results are shown in Table 3.

According to Table 3, if a resin bonded wire saw (a1) or a resin bonded wire saw (a2) is used, heat or stress strain accompanying cutting can be obtained as compared with cutting by electroplating or cutting by free abrasive method. Wafers with less wafer damage and thinner damage layers.

The above characteristics are related to achieving a higher power generation efficiency of the solar cell. In other words, it has been confirmed that the complete removal of the damaged layer (processed metamorphic layer) by brittle fracture is an indispensable operation for the long life of electrons or holes (carriers), and the resin adhesive line obtained by the present invention is obtained. Saw in the damage layer (processing metamorphic layer) is less helpful in reducing the steps before the battery step, which helps to increase the power generation efficiency of 0.12~0.15%.

Table 4 shows the measurement results of the strength of the three-point bending of the wafer cut out under the same conditions as those in Table 2 by cutting (A1), cutting (A2), and cutting (B). Among them, a single crystal ingot is used as a twin ingot, and the cutting directions of the measurement samples are overlapped with each other.

Measuring condition

Sample: 5 wafers overlap

Bending span length: 30 mm

Crosshead speed: 5 mm/min

According to Table 4, when a resin bonded wire saw (a1) or a resin bonded wire saw (a2) is used, a wafer having a high bending strength can be obtained as compared with cutting by a plating method or cutting by a free abrasive grain method.

[Industrial availability]

The resin bonded wire saw obtained by the present invention is used for simultaneous efficiency A wafer used for cutting a TFT substrate, a solar cell substrate, a compound semiconductor substrate, or the like from a single crystal or a polycrystalline ingot such as a gallium arsenide, a gallium arsenide, or a copper indium selenium (CIS) may not be used. Missing tools. In addition, it is a tool which is indispensable for cutting out a wafer used for an optical device substrate or an electronic device substrate from a magnet, a crystal, a glass, a sapphire or the like at the same time.

2‧‧‧ concave mirror

3‧‧‧core

4‧‧‧Lights

6‧‧‧Concentration Department

8‧‧‧Reflective surface of concave mirror 2

Fig. 1 is an explanatory view showing a state in which a radiation from a illuminator is condensed by a concave mirror of a half cylinder type.

Fig. 2 is an example of an emission spectrum of a rod-shaped lamp in which a tungsten wire is sealed in a quartz glass tube used in the present invention.

Figure 3 is a graph showing the distribution of wafer thickness.

Figure 4 is a graph showing the distribution of variations in thickness within the wafer.

Claims (5)

An adhesive composition for a resin bonded wire saw, which is used in the manufacture of a resin bonded wire saw in which a surface of a metal core wire is fixed with a resin binder; and It is an essential ingredient. The adhesive composition for a resin-bonded wire saw of claim 1, which further comprises 5 to 20 parts by weight of a curing agent of a novolak-type phenol-based resin. A slurry for a resin-bonded wire saw comprising the adhesive composition of claim 1 or 2, a solvent of the adhesive composition, abrasive grains, and a filler containing inorganic particles. A method for manufacturing a resin bonded wire saw, comprising: preparing a slurry according to claim 3 and a metal core wire, applying the slurry to the surface of the metal core wire, and heating the ink with infrared rays containing near infrared rays A heating step of causing the above-mentioned adhesive composition to undergo a crosslinking reaction is carried out by coating the slurry. A method of producing a resin bonded wire saw according to claim 4, further comprising the steps of: winding the wire obtained in the heating step to obtain a wound body, and heating the wound body to a reheating step.