JP5792208B2 - Resin bond wire saw - Google Patents

Description

  The present invention relates to a solar cell / electronic substrate, a compound semiconductor substrate such as gallium arsenide represented by a wafer formed by slicing a large-diameter silicon ingot, or a magnetic material such as a magnetic material, crystal, glass, etc. It relates to fixed abrasive wire saws used for cutting optical substrates, etc., especially fixed abrasive wire saws suitable for precision cutting in hard and brittle materials, especially resin bond wire saws Wire saw) fixed to the wire.

  In the cutting of silicon ingots for TFT (thin film transistors) and solar cells, which have been increasing in diameter year by year, the inner peripheral grinding wheels (ID blades) that have been used in the past have reduced processing efficiency and productivity, and the generation of damaged layers Problems such as a decrease in cutting dimensional accuracy and the need for a large apparatus have been pointed out. For this reason, in recent years, cutting using a wire saw has been actively performed. The wire saw performs a cutting operation by running a wire together with cutting abrasive grains while being pressed against a workpiece. In addition, although the wire used for this purpose is also called a saw wire, it is called a wire saw in this specification. Cutting using a wire saw is easy to cope with the increase in the diameter of silicon ingots, and unlike an inner peripheral grinding wheel that can obtain only one wafer from a single ingot, multiple wafers can be processed simultaneously. Multi-cutting is possible.

  There are two types of wire saws used in such cutting processes: free abrasive grains and fixed abrasive grains. In the free abrasive type, a wire such as a piano wire as a core material is used by applying an abrasive liquid in which fine abrasive grains such as diamond and silicon carbide are dispersed in an aqueous slurry or oil. In this case, cutting is performed by running while applying tension to the wire coated with the abrasive liquid. (For example, refer to Patent Document 1). As a result, the cutting is gradually performed by the abrasive grains interposed in the gap between the wire and the workpiece.

  However, with this method, it is necessary to continue supplying an appropriate amount of abrasive grains to the cutting interface. Especially, the viscosity of slurry and oil etc. fluctuates slightly depending on the temperature, etc., resulting in management related to wafer quality such as thickness variation and waviness. Besides that, it is difficult. In addition, since this method allows the abrasive grains to move freely during wafer cutting, not only the wafer but also the wire is rubbed, and there is a limit to reducing the wire diameter without disconnection. Further, since the wafer surface is polished by abrasive grains that move freely, there is a concern that a thick work-affected layer (damaged layer) related to the photoelectric conversion efficiency is formed.

  As a method for solving such a problem, a fixed abrasive wire saw in which diamond or the like is fixed to a wire has been proposed. Examples of means for fixing the diamond include a resin bond method and an electrodeposition method.

  In the electrodeposition method, diamond is fixed to a piano wire by nickel plating or the like (see, for example, Patent Documents 2 and 3). This method is a method in which diamond is embedded in the nickel film while nickel is deposited on the surface of the piano wire in the nickel plating solution, and is firmly fixed. The strong fixing force is excellent from the point of cutting the ingot, The wire diameter gradually increases in the nickel plating process.

  In this method, it is desirable to deeply embed diamond in the plating layer and fix it physically firmly. Since the adhesion of diamond is governed by the deposition amount of the plating film, the productivity is very poor and the cost is low. There are problems such as high. Furthermore, since the wire diameter of the wire is thick due to nickel, it is conceivable that when a long wire is repeatedly wound around a pulley, the wire is likely to cause fatigue fracture.

  Furthermore, a metal layer made of solder, etc., having a thickness of 5 to 40% of the grain size of diamond (abrasive grains) was formed on the wire, and the diamond was adhered and solidified in the molten state of the metal layer. A featured fixed abrasive wire saw is disclosed (for example, see Patent Document 4). In such a method, if the melting point of the solder constituting the metal layer is high, the wire is excessively heated due to melting of the metal layer, the wire is tempered, and the possibility that the tensile strength of the wire is reduced increases. Therefore, it becomes difficult to select a wire material. For example, it is difficult to use a piano wire or a hard steel wire whose hardness and tensile strength are reduced by tempering of the core wire at a relatively low temperature as a core wire. Instead, it is susceptible to repeated bending due to stainless steel or embrittlement. A tungsten wire or the like having the same tensile strength is used. On the other hand, when the melting point of solder or the like constituting the metal layer is low, the metal layer is melted by heat generated by friction during cutting of the workpiece by the wire saw, and the abrasive grains easily fall off the wire.

  In the resin bond method, for example, a mixture of a resin adhesive such as a phenol resin and an abrasive such as diamond is coated on a piano wire by using a floating die and heat-treated using an enamel baking furnace (see Patent Document 4). It is something to apply. The diamond is fixed by the cured resin (see, for example, Patent Documents 5, 6, and 7). As an enamel baking furnace, a hot air drying method is known (for example, see Patent Documents 8 and 9). The resin bond method is suitable for manufacturing a relatively long and inexpensive wire saw. Furthermore, since the vibration of the wire generated during the cutting of the ingot is absorbed by a soft resin, such as phenol resin, compared to metals, the wire saw can be run at a high speed in the cutting of the ingot, and is stable. Cutting can be performed at high speed. Moreover, a thin wafer can be obtained. On the other hand, since the holding power by the resin is low, diamonds drop off one after another during cutting, and the sharpness and thinning of the wire diameter are likely to occur, and the short life is pointed out as a drawback. In addition, when using a thermosetting resin adhesive, the curing cannot be performed in a short time, and if it is performed at a high temperature, there is a problem with foaming due to decomposition of the curing agent and volatile components accompanying the reaction. For this reason, there has been a problem that the production speed of the wire saw cannot be increased.

Patent Document 1 Japanese Patent Application Laid-Open No. 2008-103690 Patent Document 2 Japanese Patent Publication No. 4-4105 Patent Document 3 Japanese Patent Application Laid-Open No. 2003-334863 Patent Document 4 Japanese Patent Application Laid-Open No. 2006-123024 Patent Document 5 Japanese Patent Application Laid-Open No. 2000-263352 No. Patent Document 6 Japanese Patent Laid-Open No. 2000-271872 Patent Document 7 Republished Patent WO 98/35784 Patent Document 8 Japanese Patent Laid-Open No. H09-35556 Patent Document 9 Japanese Patent Laid-Open No. 2010-267533

  An object of the present invention is to provide a resin bond wire saw having good machinability and a long life.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have used an adhesive composition mainly composed of a novolak type phenol resin as an adhesive resin, and has received infrared rays. It was found that by efficiently irradiating in a short time by irradiation, a long-life resin bond wire saw having excellent machinability and less abrasive removal was efficiently produced, and the present invention was completed.

  The gist of the present invention is a resin bond wire saw in which abrasive grains are fixed to the surface of a metal core wire through a resin bond mainly composed of a phenol resin, and the resin constituting the resin bond is MALDI. -A peak showing a 208 (m / z; mass / charge) interval fragment was detected in the cation by mass spectrometry using the TOF-MS method, and softened to around 180 ° C by the thermogravimetric / differential thermal analysis (TG-DTA) method. It is a resin bond wire saw in which the peak of a point is detected.

The resin constituting the resin bond is
Novolac type phenol resin 100 parts by weight Resol type phenol resin 10 to 30 parts by weight Amine-based silane coupling agent 0.1 to 5 parts by weight An essential component may be included.

  The present invention provides a resin bond wire saw with good machinability and long life.

Explanatory drawing which shows the aspect which condenses the emitted light from a light-emitting body with a semi-cylindrical concave mirror. An example of the emission spectrum of the rod-shaped lamp which enclosed the tungsten filament in the quartz glass tube used for this invention. The cation detection chart of the resin cured material extract | collected from the resin bond wire saw. The cation detection chart of the resin cured material extract | collected from the resin bond wire saw. Anion detection chart of cured resin collected from resin bond wire saw. Anion detection chart of cured resin collected from resin bond wire saw. A differential thermal analysis chart of a resin-cured resin bond wire saw.

  The present invention is a resin bond wire saw in which abrasive grains are fixed to the surface of a metal core wire through a resin bond containing a phenol resin as a main component. This resin bond is formed by curing an adhesive composition mainly composed of a phenol resin. This adhesive composition preferably contains a resol type phenol resin in addition to the novolac type phenol resin.

  The novolak type phenol resin is a resin obtained by condensation reaction of a phenol compound such as phenol, cresol, bisphenol A and an aldehyde such as formaldehyde in the presence of an acidic catalyst. The resol type phenol resin is obtained by condensing a phenol compound such as phenol, cresol, bisphenol A and an aldehyde such as formaldehyde with a basic catalyst.

  This adhesive composition may further contain a curing agent for a novolac type phenolic resin. The novolak type phenol resin curing agent is preferably contained in an amount of 5 to 20 parts by weight based on 100 parts by weight of the novolak type phenol resin.

  When this adhesive composition contains a curing agent for novolac type phenolic resin, if the blending ratio of the curing agent exceeds 20 parts by weight with respect to 100 parts by weight of novolac type phenolic resin, a gas generated by decomposition of the curing agent during curing However, the cured resin may swell and generate cracks. In addition, when the blending ratio of the curing agent is less than 5 parts by weight with respect to 100 parts by weight of the novolak type phenol resin, there is a possibility that the curing of the novolak resin may be insufficient when the blending ratio of the resol type phenol resin is small. is there. At this time, a resol type phenol resin may be added as appropriate, but the mixing amount of the curing agent of the novolac type phenol resin is adjusted according to the mixing amount of the resol type phenol resin (5 to 20 parts by weight). It is more preferable to set appropriately within the range.

  Examples of the curing agent for the novolak type phenol resin include hexamethylenetetramine, methylol melamine, and methylol urea. Of these, hexamethylenetetramine is preferred because the curing time of the resin is short.

  This adhesive composition may further contain, for example, 5 to 15 parts by weight of a phenol compound such as phenol, cresol, or bisphenol A. Further, it may contain some aldehyde such as formaldehyde (for example, 1 part by weight or less). Furthermore, it may be contained as long as the basic catalyst or moisture is small.

  When this adhesive composition contains 10 to 30 parts by weight of a resol type phenolic resin with respect to 100 parts by weight of a novolak type phenolic resin, a dense three-dimensional network structure can be obtained by curing and crosslinking of the phenolic resin. . Thereby, strong joining with an abrasive grain is realizable. When the resol type phenol resin is larger than 30 parts by weight with respect to 100 parts by weight of the novolak type phenol resin, the viscosity of the paste described later is lowered. For this reason, when the resol type phenol resin is larger than 30 parts by weight with respect to 100 parts by weight of the novolac type phenol resin, a viscosity suitable for applying the paste by running the core at high speed cannot be obtained. When the resol type phenol resin is smaller than 10 parts by weight with respect to 100 parts by weight of the novolak type phenol resin, the crosslinking rate at the time of curing of the adhesive composition becomes slow. For this reason, when the resol type phenol resin is smaller than 10 parts by weight with respect to 100 parts by weight of the novolak type phenol resin, it becomes difficult to cure the paste in a short time while running the core wire, and a high performance resin bond Cannot produce wire saws at high speed. In order to cure the paste in a short time, it is more preferable to add a novolac-type phenol resin curing agent in the above proportion as appropriate.

  In this adhesive composition, 0.1 to 5 parts by weight of an amine silane coupling agent is blended with 100 parts by weight of a novolak-type phenolic resin, so that the adhesive strength between the abrasive grains and the core wire and the adhesive is increased. Will increase. When the mixing ratio of the amine-based silane coupling agent is less than 0.1 parts by weight with respect to 100 parts by weight of the novolak-type phenol resin, sufficient adhesion between the phenol resin and the nickel-coated abrasive grains can be obtained. Absent. In such a case, the cutting ability of the resin bond wire saw is inferior to the resin bond wire saw manufactured using the adhesive composition in which the amine-based silane coupling agent is blended in the above blending ratio. If the mixing ratio of the amine-based silane coupling agent is larger than 5 parts by weight with respect to 100 parts by weight of the novolak type phenolic resin, foaming may occur due to thermal decomposition during curing, or the novolac type phenolic resin may be cured. However, sufficient adhesive force cannot be obtained between the phenol resin and the abrasive grains. In such a case, the cutting ability of the resin bond wire saw is reduced.

  Examples of amine-based silane coupling agents include 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane. Examples include 3-aminopropyltriethoxysilane.

Resin constituting the resin bond in the resin bond wire saw of the present invention,
Novolak type phenolic resin 100 parts by weight Resole type phenolic resin 10-30 parts by weight Amine-based silane coupling agent Composition comprising 0.1-5 parts by weight as an essential component is a resin bond with good machinability and long life It is preferable when obtaining a wire saw.

The production method for producing the resin bond wire saw of the present invention using this adhesive composition is as follows:
Preparing a paste comprising the adhesive composition described above, a solvent for dissolving the adhesive composition and adjusting the viscosity of the paste, abrasive grains, and a filler comprising inorganic particles;
A step of preparing a metal core wire;
Applying the paste to the surface of the metal core wire;
And a heating step of heating the applied paste with infrared rays to cause the adhesive composition to undergo a crosslinking reaction with dehydration.

  By this heating step, the adhesive composition is rapidly dehydrated and condensed to form a dense three-dimensional crosslinked structure.

  The paste can be continuously applied to the surface of the metal core wire by, for example, a dispenser (syringe) method in which the paste is extruded from a small-diameter nozzle and applied to the core wire, or a floating die method. The amount of paste applied is preferably set so that the concentration of abrasive grains is 50-120. The degree of concentration is a value using the ratio of the area of the abrasive grains in the projected area of the outer surface of the wire saw as an index. In this specification, the degree of concentration is when the projected area of the abrasive grains in the total projected area is 15%. Is 100. For example, the concentration is 200 when the projected area of the abrasive grains in the total projected area is 30%, and the concentrated degree is 50 when the projected area of the abrasive grains in the total projected area is 7.5%. To do.

  When the paste is continuously applied to the traveling core wire, the viscosity of the paste is adjusted to 3 to 6 Pa · s (Pascal · second) by adding a solvent to the adhesive composition to obtain an appropriate and uniform coating amount. In addition, it is preferable. For example, the solvent is preferably set in the range of 100 to 200 parts by weight with respect to 100 parts by weight of the adhesive composition. Although it does not specifically limit as a solvent which adjusts the viscosity of a paste, Among the isomers of o-, m-, and p-, o-cresol with a low boiling point is preferable from a reactive point.

  The abrasive grain used in the present invention is not particularly limited as long as it is an abrasive grain for a fixed abrasive wire saw, but diamond abrasive grains, cubic BN abrasive grains, alumina abrasive grains, silicon carbide abrasive grains and the like are exemplified. The

  In particular, since the diamond abrasive grains have extremely high thermal conductivity, the temperature of the shadowed portion of the abrasive grains immediately rises in heating for a short time. The use of diamond abrasive grains is preferred because a chemical reaction relating to uniform fixation is thereby promptly performed. The size of the abrasive grains is selected according to the purpose or according to the core wire diameter, but is preferably several microns to 25 microns from the viewpoint of cutting a silicon ingot with a small kerf loss (cutting allowance). Furthermore, the abrasive grains used in the present invention exclude copper (if copper remains even as a small amount of impurities, a deep level is created in the band gap of silicon by a baking process such as a silver electrode. It may be diamond coated with a metal such as nickel or titanium, which reduces power generation efficiency when used as a battery. When diamond coated with nickel is used, the resin bond wire saw obtained according to the present invention has a sled or saw mark as compared with a diamond abrasive fixed wire saw by electroplating (electrodeposition) such as nickel. Slicing to obtain a silicon wafer having a very smooth surface.

  In order to avoid clogging due to silicon dust generated during slicing, the abrasive grains must be appropriately dispersed and fixed on the core wire on the scale referred to as the above-mentioned concentration degree. Furthermore, in this invention, it is preferable that 50-120 weight part is mix | blended with an abrasive grain with respect to 100 weight part of adhesive compositions.

  A steel wire is preferably used as the core wire used in the present invention. The wire diameter is not particularly limited, but is preferably 0.3 to 0.05 mm. Steel wire includes heat-treated spring steel wire such as high carbon steel and medium carbon low alloy steel, hard steel wire, piano wire and stainless steel wire, cold rolled steel wire and oil tempered wire wire made of spring steel, low Examples include steel wires with high toughness and high fatigue strength such as alloy steel, medium alloy steel, high alloy steel, and maraging steel.

  By continuously applying the paste to the traveling core wire and continuously heating the traveling core wire while traveling, the applied paste is heated and cured. This heating is performed by irradiating the applied paste with infrared rays. When hot air is heated in a conventional enamel furnace, etc., heat curing occurs from the outer surface of the paste, and as a result of forming a surface film, the water generated by the dehydration condensation reaction is confined inside, and the adhesive is accompanied by the gasification of this water Foaming is likely to occur. On the other hand, when the paste is heated with infrared rays using a lamp or the like, near infrared rays having a wavelength of about 1 μm are efficiently absorbed into water, so that the dehydration reaction is performed in a short time and the crosslinking polymerization is completed. . Moreover, since water is excited and evaporates in a short time, foaming is hardly generated in the adhesive. This infrared ray preferably has one or a plurality of spectral peaks in the near infrared band having a wavelength of 0.7 to 2.5 μm. In particular, heating with near infrared rays having a wavelength of about 1 μm (in the range of 0.9 to 1.3 μm) promotes dehydration and cross-linking of the adhesive composition, and foams the adhesive with the gasification of water generated by the dehydration reaction. This is preferable because it can prevent the foaming of the adhesive after curing.

  Infrared rays effectively accelerate the chemical reaction of curing the adhesive composition, and the curing reaction takes place at a higher speed than when the resin is cured by heating with hot air, resulting in a higher-order structure with uniform molecules. It is done. As a result, a peak indicating 208 (m / z) -spaced fragments in the cation is detected in the cured resin by mass spectrometry using the MALDI-TOF-MS method. In addition, a clear peak corresponding to the softening point is detected in the vicinity of 180 ° C. by differential thermal analysis (DTA). Note that the temperature of this peak may vary slightly depending on measurement conditions such as the rate of temperature rise during differential thermal analysis, and is in the range of about 175 ° C. to about 182 ° C. The expression of the peaks in such differential thermal analysis reflects the uniform higher order structure of the molecules together with the peaks indicating fragments of 208 (m / z) intervals. Furthermore, due to the uniform higher order structure of the molecules, the cured resin bond has a high hardness, and the abrasive grains are firmly held on the wire. Thereby, the wire saw excellent in cutting performance is obtained.

  As a method of heating the applied paste by infrared irradiation while the core wire to which the paste is applied is traveling, there is a method as shown in FIG. In this system, a semi-cylindrical concave mirror 2 and a light emitter 4 that emits infrared light are used. In this method, the core wire 3 coated with the paste travels in the longitudinal direction of the concave mirror 2 (perpendicular to the paper surface in the drawing), while the light emitters 4 are arranged linearly in parallel with the longitudinal direction of the concave mirror 2. The semi-cylindrical concave mirror 2 is arranged so that the radiated light is condensed to a traveling path of the core wire to a size of about 10 mmφ. Reference numeral 8 denotes a reflecting surface of the concave mirror 2. The concave mirror 2 and the light emitter 4 may be paired and arranged in combination with the traveling path of the core wire as the center of symmetry. An infrared lamp is preferably used as the illuminant 4 for efficient heating in a short time.

  The length of the condenser 6 is determined by the size and number of the light emitters 4 and the concave mirror 2. By using the condensing unit 6 as a heating zone, the applied paste can be heated by infrared irradiation while the core wire to which the paste is applied is traveling. The heating zone can be configured using an infrared lamp. When the infrared lamp is used, the length of the light collecting unit 6 can be set to 400 to 1000 mm, for example. The heating zone may be formed by arranging a plurality of infrared lamps in series in the running direction of the core wire.

  As the illuminant 4, it is preferable to use an infrared lamp having an emission spectrum peak in the near-infrared band. Preferable infrared lamps include, for example, a xenon short arc lamp (Short-arc Xenon Lamp) and a rod lamp in which a tungsten filament is sealed in a quartz glass tube.

  By the way, it is extremely difficult to accurately grasp the temperature received by the wire saw traveling in the zone heated in a short time. Therefore, the temperature at which> 95% of the breaking strength of the core wire itself can be secured is set to the outside with the aim of tempering the core wire and reducing the breaking strength when heated. With this heating method, the adhesive coated core can be formed in a short time without foaming the adhesive at a high speed of 1000 to 2000 mm / sec (seconds). Incidentally, when measured with a sheath type thermocouple having a diameter of 1.0 mm, the lamp output is controlled on the assumption that the temperature of the condensing portion 6 is preferably 500 to 800 ° C.

  The method of heating with infrared rays may be a method of irradiating an object with an infrared laser.

  In addition, the filler (filler) which consists of inorganic particles is mix | blended with this paste. The filler is preferably blended in an amount of 20 to 100 parts by weight with respect to 100 parts by weight of the adhesive composition. More preferably, the filler is blended in an amount of 30 to 60 parts by weight. As the filler, diamond (about 2 to 3 μm) may be used, but inorganic materials having various shapes and hardnesses can be used. As an example, silicon carbide grains are used. The mixing of the filler has an effect of suppressing the thermal expansion / contraction of the resin and reducing the falling off of the abrasive grains during the ingot cutting.

  A resin bond wire saw having more stable performance can be obtained by reheating the wire heated by the above-described infrared heating (core wire coated with a paste). This reheating is performed for the purpose of removing the thermal strain received by the resin layer and the core wire that repeats expansion and contraction due to the above-mentioned short-time curing by infrared heating. If the wire (core wire coated with paste) is wound around a bobbin with a constant tension, for example, about 10 N, and the wound body is reheated while the adhesive is incompletely cured in the infrared heating described above, the wire They stick together, making disentanglement impossible, and forcibly disentanglement causes problems such as peeling of the adhesive. Therefore, in principle, it is preferable that the curing of the adhesive composition is almost completed in infrared heating. Due to the reheating, the breaking stress of the wire saw and the molecular structure of the adhesive composition cured by infrared heating hardly change.

  Reheating is preferably performed at 100 to 200 ° C. for 1 to 5 hours. Moreover, even if it takes time for this reheating, since reheating can process many winding bodies at once, productivity as a whole production process of a resin bond wire saw does not fall greatly. Thus, productivity of a resin bond wire saw can be improved by combining high-speed heating of a wire and reheating of a winding body and producing efficiently.

  The resin bond wire saw of the present invention has a larger cutting depth than a resin bond wire saw produced by a conventional method. This depth of cut refers to the depth of cut when a piece to be cut having a predetermined shape is pressed against a wire saw, the wire saw is reciprocated and cut until the wire saw is 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 resin-bonded wire saw of the present invention has a significantly improved adhesion strength of the abrasive grains to the core wire and has a long life. In addition, since the resin bond wire saw of the present invention has high adhesive strength to the core wire of the abrasive grains, wafer warpage, waviness, and thickness variation (in the thickness direction) as an index of flatness when a large number of wafers are cut out. Any difference between the maximum and minimum measured height (TTV) shows a small numerical value that is 25% or more superior to a resin bond wire saw manufactured by the conventional method. Furthermore, the resin bond wire saw of the present invention can provide a smooth silicon wafer having a Ra or Ry value of about 20% which is an index of surface roughness. Furthermore, a wafer having a thin work-affected layer (damage layer) on the surface can be obtained by the resin bond wire saw of the present invention. In addition, from the measurement result of the three-point bending stress of the wafer, a wafer with high bending strength can be obtained because there are few starting points of fracture due to the work-affected layer.

  The cutting performance of the resin bond wire saw of the present invention is confirmed by the following experimental example.

[Experimental Example 1]

  Using an adhesive composition for a resin bond wire saw having the following composition, the paste was adjusted at the following blend ratio, and a resin bond wire saw was produced by the following wire saw production line.

[Example 1]
-Blending ratio of adhesive composition for resin bond wire saw 80 parts by weight of novolak type phenolic resin composition (trade name: Shonor BRP-5417)
Breakdown Novolac-type phenolic resin ((C ₆ H ₆ .CH ₂ O) _n )
86 wt%, phenol 5 wt%, hexamethylenetetramine
9% by weight
Resol type phenolic resin composition (trade name: Shonor BRL-131) 20 parts by weight
Breakdown Resol type phenolic resin ((C ₆ H ₆ .CH ₂ O) _n ) 80
Wt%, phenol 5.9 wt%, formaldehyde 0.6 wt
% By volume, NaOH 1.2% by weight, moisture 12.2% by weight, other
Auxiliary agent 0.1% by weight
1 part by weight of an amine-based silane coupling agent (trade name: Silaace S330) and a blending ratio of paste 100 parts by weight Diamond abrasive grains coated with nickel (average particle size: 10 to 20 μm) 80 parts by weight filler ( Silicon carbide powder; # 8000) 50 parts by weight of solvent (o-cresol) 150 parts by weight of wire saw production line

Core wire feeder → Coating device → Heating device → Winding machine ... → Reheating furnace

Core wire feeder: A normal feeder that feeds the wound core wire.
Coating device: Applying paste uniformly to the core surface using a water jet die
did.
Heating device: a device for heating the core wire coated with paste. As this device, transparent
A rod-shaped lamp with a tungsten filament sealed in a quartz glass tube was used.
Infrared Gold Image Furnace manufactured by ULVAC-RIKO, Inc .: Model RHL-E4
Three 10-N (heating length 265 mm, maximum output 4 kW) were used in series.
As the protective tube, a transparent quartz glass tube having a high lamp wavelength transmission was used.
FIG. 2 shows the energy spectral distribution of this rod lamp.
Winder: A normal winder that winds a wire saw around a bobbin.
Core wire: Piano steel wire (wire diameter: 120 μm, breaking strength: 42N)
Core wire travel speed: 1200mm / sec
Application amount of paste: 0.01 g / m
Infrared Gold Image Furnace: PID controlled to be 720-750 ° C. by R thermocouple measurement (actual temperature is a temperature corresponding to a wire saw breaking strength> 40 N).
Reheating furnace: Stores the wire saw (adhesive and abrasive grains) wound around the bobbin with a winder,
Convection heating furnace to heat.
Heating in the reheating furnace: 180 ° C. × 2 hours

[Example 2]
The mixing ratio of the adhesive composition for the resin bond wire saw is 85 parts by weight of a novolak type phenol resin composition (trade name: Shonor BRP-5417) and 15 parts by weight of a resole type phenol resin composition (trade name: Shonor BRL-131). Part by weight Amine-based silane coupling agent (trade name: Silaace S330) 1 part by weight paste composition Adhesive composition 100 parts by weight Diamond coated abrasive coated with nickel (average particle size: 10 to 20 μm) 80 parts by weight filler (Silicon carbide powder; # 8000) 50 parts by weight solvent (o-cresol) A resin bond wire saw was produced in the same manner as in Example 1 except that 170 parts by weight was used.

[Comparative Example 1]
The same as in Example 1 except that a commercially available novolac type phenolic resin composition (manufactured by Sumitomo Bakelite Co., Ltd.) was used as the adhesive composition for the resin bond wire saw, and a vertical baking furnace used for baking enamel was used as the heating device. A wire saw was obtained. In this vertical baking furnace, heating was performed at a furnace temperature of 300 ° C. for a heating time of 20 minutes. In this vertical baking furnace, the core wire is heated by heated air (thermal convection) circulating in the furnace core tube (alumina), and the heating element is a nichrome wire.

The cutting performance of the resin bond wire saw (a1) obtained in Example 1 and the resin bond wire saw (a2) obtained in Example 2 is compared with the resin bond wire saw (b) obtained in Comparative Example 1. did.
Cutting Performance Test A polycrystalline silicon piece of 1 cm × 1 cm × 2 mm was set above a horizontally stretched wire, the piece was moved downward and cut to measure the cutting depth.
Cutting conditions Wire motion: Amplitude 80 mm, Reciprocating speed 400 mm / min (min) Cutting time: Piece descending speed to wire breakage: 0.9 mm / min (min)
Table 1 shows the results of the cutting performance test. Table 2 shows the residual rate of the abrasive grains of the wire after the test.

  From Table 1, the result that the cutting depth of the resin bond wire saw obtained in Examples 1 and 2 was much deeper than that of the resin bond wire saw obtained in Comparative Example 1 was obtained. Moreover, from Table 2, the result that the resin bond wire saw obtained in Example 1 was much larger than the resin bond wire saw obtained in Comparative Example 1 was also obtained with respect to the residual rate of abrasive grains.

  In order to investigate the reason for this difference, the following experiment was conducted to examine the hardness of the cured resin.

[Experiment 2]
Case 1: The resin composition used in Example 1 was cured by heating. (Heating conditions: 15 ° C / hr up to 180 ° C and hold at 180 ° C for 2 hr)
Case 2: The novolac type phenolic resin composition used in Comparative Example 1 was heat cured under the same heating conditions as in Case 1.

  Table 3 shows the results of measuring the Rockwell hardness of the obtained cured product using a hardness meter (ATK-F3000; 1/4 "steel ball used, load 100 kgf) manufactured by Akashi Seisakusho.

  Table 3 shows that a cured product obtained by curing the resin composition (a mixture of a novolac type phenol resin and a resol type phenol resin) used in Example 1 is harder than a cured product obtained by curing a novolac type phenol resin. This is one of the reasons why the wire saw of the present invention is excellent in machinability (Tables 1 and 2).

[analysis]
A resin cured product was collected from the resin bond wire saw (a1) obtained in Example 1 and the resin bond wire saw (b) obtained in Comparative Example 1, and the network molecular structure and physical properties were examined.

Mass structure was analyzed by molecular structure MALDI-TOF-MS method.
(MALDI: matrix-assisted laser desorption / ionization method, TOF-MS: time-of-flight mass spectrometry)
Equipment used: AXIMA-CFR ⁺ (SHMAZU) manufactured by Shimadzu Corporation
Analysis mode: Linear mode Cation and anion detection Vacuum degree: 10 ⁻⁵ Pa or less Matrix: 2,5-dihydroxybenzoic acid Laser wavelength: 337 nm (nitrogen laser)

Measurement Results FIGS. 3 to 6 show measurement charts of mass spectrometry by the MALDI-TOF-MS method.
FIG. 3 is a cation detection chart of a cured resin obtained from the resin bond wire saw (b) obtained in Comparative Example 1.
FIG. 4 is a cation detection chart of a cured resin obtained from the resin bond wire saw (a1) obtained in Example 1.
FIG. 5 is an anion detection chart of a cured resin obtained from the resin bond wire saw (b) obtained in Comparative Example 1.
FIG. 6 is an anion detection chart of a cured resin obtained from the resin bond wire saw (a1) obtained in Example 1.

In the chart shown in FIG. 4, peaks (arrows) indicating fragments at intervals of 208 (m / z) were detected. These 208 (m / z) -spaced fragments are represented by the following structural formula (structural unit: C ₁₄ H ₁₂ O ₂ : 212).

芳香環を含む４つの部位で架橋が開裂（フラグメントイオン）した結果生じたものと推測され、実施例１で得られたレジンボンドワイヤーソー（ａ１）から採取した樹脂硬化物中に下記構造

The following structure is assumed in the resin cured product taken from the resin bond wire saw (a1) obtained in Example 1, which is presumed to have been generated as a result of cleavage (fragment ions) at four sites including the aromatic ring.

が反復フラグメントとして網状高分子構造に規則正しく配列することを示している。

Are regularly arranged in a network polymer structure as repetitive fragments.

  In FIGS. 3, 5, and 6, peaks (arrows) indicating fragments at regular intervals were not detected. The cured resin obtained from the resin bond wire saw (b) obtained in Comparative Example 1 seems not to have a significant structure represented by Chemical Formula 1.

  From the above results regarding FIGS. 3 to 6, it is considered that the molecular structure showing fragments of 208 (m / z) spacing is caused by irradiation with the adhesive composition of the present invention and infrared rays including near infrared rays. It is.

Differential Thermal Analysis FIG. 7 shows a differential thermal analysis chart measured from the resin bond wire saw (a1) obtained in Example 1 and the resin bond wire saw (b) obtained in Comparative Example 1 under the following conditions of the cured resin. Show.
Device used: TG8120 (Rigaku)
Temperature increase rate: 10 ° C / min (min)
Atmosphere: N ₂ gas flow standard material: Alumina (Al ₂ O ₃ )
Sample weight: about 10mg

  From FIG. 7, a clear softening point peak was detected in the range of 175 to 180 ° C. in the cured resin chart obtained from the resin bond wire saw (a1) obtained in Example 1. In the resin cured product collected from the resin bond wire saw (b) obtained in Comparative Example 1, only a small softening point peak was observed around 190 ° C. This seems to be because the higher order structure of the molecule of the cured resin sample collected from (b) was not uniform and the transition accompanied by the structural change was not clearly expressed. In addition, it is considered that the difference in hardness shown in Table 3 occurred due to the fact that the higher-order structure of the molecule is not uniform, which affects the hardness of the resin. Therefore, the resin bond wire saw (a1) obtained in Example 1 is a higher-order structure based on a certain structural unit provided by the above-mentioned 208 (m / z) -spaced fragments. Seems to have appeared as a high hardness.

    The resin bond wire saw of the present invention can simultaneously use wafers used for TFT substrates, solar cell substrates, compound semiconductor substrates, etc. from single crystals or polycrystalline ingots such as silicon, gallium arsenide, copper, indium, selenium (CIS). It is an indispensable tool for cutting out efficiently. In addition, it is an indispensable tool for efficiently cutting out wafers used for optical equipment substrates, electronic equipment substrates, etc. from magnetic materials, quartz, glass, sapphire and the like simultaneously.

Claims (2)

A resin bond wire saw in which abrasive grains are fixed to the surface of a metal core wire through a resin bond whose main component is a phenol resin, and the resin constituting the resin bond is obtained by mass spectrometry using a MALDI-TOF-MS method. A resin bond wire saw in which peaks indicating fragments of 208 (m / z) intervals are detected in a cation, and a peak corresponding to a softening point is detected at around 180 ° C. by differential thermal analysis by the TG-DTA method. The resin constituting the resin bond is
The resin-bonded wire saw according to claim 1, wherein the resin-bonded wire saw is a composition comprising, as an essential component, a novolac-type phenol resin, 100 parts by weight, a resol-type phenol resin, 10-30 parts by weight, an amine-based silane coupling agent, 0.1-5 parts by weight.

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