JPWO2013179498A1 - Adhesive composition for resin bond wire saw and method for producing resin bond wire saw - Google Patents

Abstract

A method for efficiently producing a resin bond wire saw with a stable ingot cutting process, a smooth and small damaged layer on the wafer surface by cutting, and an adhesive for the resin bond wire saw suitable for the method Trying to provide a composition. A resin-bonded wire saw in which abrasive grains are fixed to the surface of a metal core wire through a resin bond. An amine silane coupling agent is an adhesive composition for a resin bond wire saw having 0.1 to 5 parts by weight as an essential component, and dissolves the adhesive composition, abrasive grains, and the adhesive composition. A resin bond wire saw manufacturing method including a heating step in which a paste containing a solvent is applied to a surface of a metal core wire, and the applied paste is heated with infrared rays including near infrared rays to crosslink the adhesive composition. is there.

Description

The present invention relates to a solar cell / electronic substrate typified by a wafer obtained by slicing a large-diameter silicon ingot, a compound semiconductor substrate such as gallium arsenide, or a magnetic material such as a magnetic material, quartz crystal, and glass. -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 (abrasives are used as resin adhesives) The present invention relates to a method for producing a wire saw fixed to a wire and an adhesive composition used in the production method.

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. 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, 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 annealed, and there is a high possibility that the tensile strength of the wire is reduced. The selection becomes difficult. For example, piano wires and hard steel wires whose hardness and tensile strength are lowered due to annealing of the core wire at a relatively low temperature cannot be used as the core wires. Instead, they are 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

  The present invention makes use of the stability of the resin bond wire saw ingot cutting process to obtain a smooth wafer in which the thickness of the work-affected layer (damaged layer) on the wafer surface by ingot cutting is small and the thickness variation is small. An object of the present invention is to provide a long-life resin bond wire saw that can be used and a method for producing a resin bond wire saw with high production efficiency. Furthermore, it aims at providing the novel adhesive composition for resin bond wire saws suitable for this method.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have determined that a resol type phenol resin and a novolak type phenol resin are used in a specific ratio as a resin for an adhesive. By combining, a composition system that can be efficiently thermally cured in a short time by infrared heating can be found, and the thickness of the damaged layer on the wafer surface by cutting can be reduced and a smooth wafer can be obtained. The present inventors have found that a resin bond wire saw with a small long life can be produced efficiently, and have completed the present invention.

The gist of the present invention is that
It is used for the production of a resin bond wire saw in which abrasive grains are fixed to the surface of a metal core wire via a resin for adhesive,
Novolak-type phenol resin 100 parts by weight Resole-type phenol resin 10-30 parts by weight Amine-based silane coupling agent An adhesive composition for resin bond wire saws containing 0.1-5 parts by weight as an essential component.

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

  Further, the gist of the present invention is a paste for a resin bond wire saw comprising the adhesive composition, a solvent for the adhesive composition, abrasive grains, and a filler made of inorganic particles. There is to be.

Further, the gist of the present invention is that
Preparing the paste and the metal core wire, applying the paste to the surface of the metal core wire,
It is in the manufacturing method of the resin bond wire saw including the heating process which heats the apply | coated said paste with the infrared rays containing near infrared rays, and carries out the crosslinking reaction of the said adhesive composition.

The method of manufacturing the resin bond wire saw further includes a step of winding the wire obtained in the heating step to obtain a wound body,
A reheating step of heating the wound body may be included.

  According to the present invention, when a large number of wafers are cut out, the wafer thickness variation, the wafer thickness deviation, and the thickness deviation variation are all small, and the damaged layer on the wafer surface due to cutting is thin and has a long service life. A method for efficiently producing a resin bond wire saw is provided. Moreover, the adhesive composition for resin bond wire saws suitable for this method is provided.

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 graph which shows distribution of the thickness of a wafer. The graph which shows distribution of the deviation of the thickness in a wafer.

The adhesive composition of the present invention is used for producing a resin bond wire saw in which abrasive grains are fixed to a surface of a metal core wire (hereinafter also referred to as a core wire) through a resin bond (resin adhesive).
Novolak type phenol resin 100 parts by weight Resole type phenol resin 10-30 parts by weight Amine-based silane coupling agent An adhesive composition for resin bond wire saws having 0.1-5 parts by weight as an essential component.

  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.

The adhesive composition of the present invention may further contain a curing agent for a novolac type phenol 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 the adhesive composition of the present invention contains a curing agent for a novolak type phenol resin, if the blending ratio of the curing agent exceeds 20 parts by weight with respect to 100 parts by weight of the novolac type phenol resin, a gas generated by decomposition of the curing agent 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.

  The adhesive composition of the present invention 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.

  The adhesive composition for a resin bond wire saw according to the present invention contains 10 to 30 parts by weight of a resol type phenol resin with respect to 100 parts by weight of a novolak type phenol resin, thereby forming a dense three-dimensional network structure by crosslinking of the phenol resin. Can be obtained. 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 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.

  The adhesive composition for the resin bond wire saw of the present invention contains 0.1 to 5 parts by weight of an amine-based silane coupling agent with respect to 100 parts by weight of a novolac type phenol resin, thereby allowing abrasive grains and The adhesive strength between the core wire and the adhesive increases. 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 compounding ratio of the amine-based silane coupling agent exceeds 5 parts by weight with respect to 100 parts by weight of the novolac type phenol resin, foaming may occur due to thermal decomposition, or the curing of the novolac type phenol resin may be affected. A sufficient adhesive force cannot be obtained between the 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.

A production method for producing a resin bond wire saw using the adhesive composition of the present invention,
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 preferably adjusted to 3 to 6 Pa · s by adding a solvent to the adhesive composition in order to obtain an appropriate and uniform coating amount. 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. The solvent for adjusting the viscosity of the paste is not particularly limited, but o-cresol having a low boiling point is preferable among the isomers of o-, m-, and p-.

  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). In addition, the abrasive grains used in the present invention exclude copper (if copper remains as an impurity, a deep level is created in the silicon band gap in the heat treatment step, so that power generation is required when used as an embodiment battery. It may be diamond coated with a metal such as nickel or titanium (which reduces efficiency). 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 heated with hot air in a conventional enamel furnace, etc., thermosetting occurs from the outer surface of the paste, a surface film is formed, and the water produced by the dehydration reaction is confined inside, and foaming occurs in the adhesive as this water is gasified. Cheap. 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.

  As a method of heating the applied paste with infrared rays while the core wire to which the paste is applied is traveling, 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. It is preferable that the temperature of the condensing part 6 is 500-800 degreeC measured with a 1.0 mm diameter sheath type thermocouple. 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 part 6 as a heating zone, the applied paste can be heated with infrared rays while the core wire coated with the paste 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.

  In the present invention, such a heating method can be performed in a short time without foaming the adhesive at a high speed of 1000 to 2000 mm / sec.

  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.

  In the present invention, 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 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 If they stick together, disentanglement becomes impossible, or if the disentanglement is forced, troubles such as peeling of the adhesive occur. Therefore, in principle, it is preferable that the curing of the adhesive composition is almost completed in infrared heating.

  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, in this invention, productivity of a resin bond wire saw can be improved by combining the high-speed heating of a wire and the reheating of a winding body, and producing efficiently.

  Conventionally, in such a reheating method of a wound body, when a wire (core wire coated with a paste) is heated under high-speed running, the wires are stuck together during reheating and defibration. There were troubles such as disabling or forcible defibration to peel off the adhesive. However, in the present invention, by adopting the above adhesive composition and employing near infrared heating, it is possible to cure the adhesive composition almost completely by heating the wire at high speed without causing trouble of foaming. It has become possible. Therefore, in the present invention, it is possible to remove the thermal strain by reheating without causing the trouble of sticking between the wires.

  The resin bond wire saw obtained by the present invention has a greater depth of cut 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 bond wire saw obtained by 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 obtained by the present invention has high adhesion strength to the core wire of the abrasive grains, variation in wafer thickness when a large number of wafers are cut out, deviation in thickness within the wafer, deviation in thickness Any of these variations is smaller than that of a resin bond wire saw manufactured by a conventional method. Furthermore, a smooth silicon wafer can be obtained by the resin bond wire saw obtained by the present invention. Furthermore, the resin-bonded wire saw obtained according to the present invention can provide a wafer having a thin work-affected layer (damaged layer) on the surface. 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.

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

[Example 1]
Compounding ratio of adhesive composition for resin bond wire saw Novolac type phenolic resin composition (trade name: Shonor BRP-5417) 80 parts by weight
Breakdown Novolac-type phenolic resin ((C ₆ H ₆ .CH ₂ O) _n ) 86 wt%, phenol 5
Wt%, hexamethylenetetramine 9 wt%
Resol-type phenol resin composition (trade name: Shonor BRL-131) 20 parts by weight
Breakdown: Resol type phenol resin ((C ₆ H ₆ .CH ₂ O) _n ) 80 wt%, phenol 5.
9 wt%, formaldehyde 0.6 wt%, NaOH 1.2 wt%, moisture 12.
2% by weight, 0.1% by weight of other auxiliaries
Amine-based silane coupling agent (trade name: Sila Ace S330) 1 part by weight (Note: The amount of novolac type phenolic resin in this formulation is 80 parts by weight × 0.86 = 68.8 parts by weight, formulation of resol type phenolic resin The amount is 20 parts by weight × 0.80 = 16 parts by weight Therefore, in Example 1, when converted as a ratio with respect to 100 parts by weight of the novolac-type phenol resin, about 23.2 parts by weight of the resol-type phenol resin is blended. Yes.)
Mixing ratio of paste Adhesive composition Diamond abrasive grains coated with 100 parts by weight of nickel (average particle size: 10 to 20 μm) 80 parts by weight of filler (silicon carbide powder; # 8000) 50 parts by weight of solvent (o-cresol) 150 Parts by weight

[Example 2]
Mixing ratio of adhesive composition for resin bond wire saw Novolac type phenol resin composition (trade name: Shonor BRP-5417) 90 parts by weight Resole type phenol resin composition (trade name: Shonor BRL-131) 10 weight Part Amine-based silane coupling agent (trade name: Silaace S330) 1 part by weight paste composition Adhesive composition 100 parts by weight Nickel coated diamond abrasive grains (average particle size: 10 to 20 μm) 80 parts by weight filler ( Silicon carbide powder; # 8000) 50 parts by weight Solvent (o-cresol) 170 parts by weight (Note: In Example 2, the resol type phenol resin is about 10.3 weights when converted as a ratio to 100 parts by weight of the novolac type phenol resin. Part blended.)

[Comparative Example 1]
Blending ratio of adhesive composition for resin bond wire saw Novolac type phenol resin composition (trade name: Shonor BRP-5417) 93 parts by weight Resole type phenol resin composition (trade name: Shonor BRL-131) 7 weight Part Amine-based silane coupling agent (trade name: Silaace S330) 1 part by weight paste composition Adhesive composition 100 parts by weight Nickel coated diamond abrasive grains (average particle size: 10 to 20 μm) 80 parts by weight filler ( Silicon carbide powder; # 8000) 50 parts by weight solvent (o-cresol) 180 parts by weight (Note: In Comparative Example 1, about 7 parts by weight of resol type phenol resin is included when converted as a ratio to 100 parts by weight of novolac type phenol resin. Has been.)

[Comparative Example 2]
Compounding ratio of adhesive composition for resin bond wire saw Novolac type phenol resin composition (trade name: Shonor BRP-5417) 70 parts by weight Resole type phenol resin composition (trade name: Shonor BRL-131) 30 weight Part Amine-based silane coupling agent (trade name: Silaace S330) 1 part by weight paste composition Adhesive composition 100 parts by weight Nickel coated diamond abrasive grains (average particle size: 10 to 20 μm) 80 parts by weight filler ( Silicon carbide powder; # 8000) 50 parts by weight (Note: In Comparative Example 2, about 40 parts by weight of resol type phenol resin is blended in terms of a ratio to 100 parts by weight of novolac type phenol resin)

[Comparative Example 3]
Blending ratio of adhesive composition for resin bond wire saw Novolac type phenolic resin composition (trade name: Shonor BRP-5417) 80 parts by weight Resole type phenolic resin composition (trade name: Shonor BRL-131) 20 weight Part paste blending ratio Adhesive composition 100 parts by weight of nickel-coated diamond abrasive grains (average particle size: 10 to 20 μm) 80 parts by weight filler (silicon carbide powder; # 8000) 50 parts by weight solvent (o-cresol) 150 parts by weight

Wire used in Examples and Comparative Examples: φ100 μm steel wire

Wire saw production line in examples and comparative examples

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: The paste was uniformly coated on the surface of the core wire with a water jet shaped die.
Heating device: a device for heating the core wire coated with paste. As this device, three infrared gold image furnaces made by ULVAC-RIKO using a rod-shaped lamp in which a tungsten filament is sealed in a quartz glass tube: model RHL-E410-N (heating length 265 mm, maximum output 4 kW) are connected in series. Using.
FIG. 2 shows the energy spectral distribution of this rod lamp.
Winder: A normal winder that winds a wire saw.

Image furnace: set temperature 725-750 ° C.
Core wire travel speed: 1200mm / sec
Application amount of paste: 0.01 g / m

Reheating furnace This is a heating furnace that houses and heats the wire (with adhesive and abrasive grains) wound by a winder.

Heating in reheating furnace 180 ° C x 2 hours

  In Comparative Example 1, the curing rate of the adhesive composition was slow, the curing of the adhesive composition was incomplete after passing through the image furnace, and the wires were stuck together after heating in the reheating furnace and could not be defibrated. . In Examples 1 and 2, defibration (rewinding) could be performed smoothly without wire sticking after heating in the reheating furnace.

  In Comparative Example 2, the viscosity of the paste is as low as 2 Pa · S even when no solvent for adjusting viscosity is used (at a running speed of the core wire of 1200 mm / sec), and the target coating amount (0.01 g / m ) Was not obtained.

The resin bond wire saw (a1) obtained in Example 1 and the resin bond wire saw (a2) obtained in Example 2 were cut using the resin bond wire saw (b1) using a photocurable resin as an adhesive. ), Comparative Example 3 The resin bond wire saw (b2) obtained was compared.
Cutting Performance Test A 1 cm cubic polycrystalline silicon piece was set below a horizontally stretched wire, the piece was moved downward and cut to measure the cutting depth.
Cutting conditions Wire motion: Reciprocating motion with amplitude of 80 mm and speed of 400 mm / min.
Table 1 shows the results of the cutting performance test.

From Table 1, the resin bond wire saws (a1) and (a2) obtained in Examples 1 and 2 were obtained with a resin bond wire saw (b1) using a photocurable resin and Comparative Example 3. The result was deeper than that of the resin bond wire saw (b2).

Moreover, the cutting (A1) using the resin bond wire saw (a1) obtained in Example 1
Cutting using electrode saw wire saw (abrasive grains: nickel-plated diamond grains, core wire diameter 100 μm) (c) (B)
FIG. 3 and FIG. 4 show the distribution of the thickness of the wafer when a large number of wafers are cut out from the silicon ingot, and the distribution of the deviation of the thickness in the wafer (difference between the maximum thickness and the minimum thickness), respectively. 3 and FIG. 4, the vertical axis represents the number of wafers, the horizontal axis in FIG. 3 represents the thickness of the wafer, and the horizontal axis in FIG. 4 represents the deviation in thickness within the wafer.
Cutting conditions:
Equipment: Multi-wire saw equipment: Komatsu NTC type Model: PV500D
Wire saw speed: 1000 m / min
Cutting speed (cutting depth of the wire cut into the silicon ingot per unit time): 0.5 mm / min
Workpiece: Polycrystalline silicon ingot; 156 mm square From FIGS. 3 and 4, when the resin bond wire saw (a1) is used, a larger number of wafers are cut out than when the electrode saw wire saw (c) is used. It was found that production with stable quality was possible with small variations in wafer thickness, deviation in thickness within the wafer, and variation in thickness deviation.

Table 2 shows cutting (A1) using the resin bond wire saw (a1) obtained in Example 1.
Cutting (A2) using the resin bond wire saw (a2) obtained in Example 2
Wire saw by electrodeposition method [Abrasive grains: nickel-plated diamond grains (particle diameter 10-20μ
m)], cutting using core diameter 100 μm) (c) (B)
Cutting by free abrasive method (using SiC abrasive # 5000) (C)
Shows the arithmetic average surface roughness (Ra) and maximum height (Ry) of the wafer according to JIS B 0601 when a wafer (pitch set to 170 μm) is cut out from the silicon ingot. The numerical values in Table 2 are average values of measured values at three locations. The cutting conditions are the same as those in FIGS.

From Table 2, when the resin bond wire saw (a1) and the resin bond wire saw (a2) are used, a smooth wafer can be obtained as compared with the cutting by the electrodeposition method or the cutting by the free abrasive method.

Next, SEM is used to determine the thickness of the damaged layer (work-affected layer) on the wafer surface cut under the same conditions as the cutting conditions in Table 2 by cutting (A1), cutting (A2), cutting (B), and cutting (C). Table 3 shows the measurement results using cross-sectional observation.

From Table 3, if the resin bond wire saw (a1) and the resin bond wire saw (a2) are used, damage to the wafer due to heat and stress strain associated with cutting compared to cutting by the electrodeposition method and cutting by the free abrasive method Therefore, a wafer having a small damaged layer can be obtained.

These characteristics are also related to achieving high power generation efficiency of solar cells. In other words, complete removal of the damaged layer (work-affected layer) that proceeds with brittle fracture is indispensable in terms of extending the lifetime of electrons or holes (carriers), and the resin bond wire obtained by the present invention It was confirmed that the saw contributes to the reduction of the process before the cell process in that it has few damaged layers (work-affected layers) and contributes to the improvement of power generation efficiency of 0.12 to 0.15%.

Table 4 shows the measurement results of the strength by three-point bending of the wafer cut under the same conditions as the cutting conditions in Table 2 by cutting (A1), cutting (A2), and cutting (B). However, a single crystal silicon ingot was used as the silicon ingot, and the measurement samples were stacked so that the cutting directions crossed alternately.
Measurement conditions Sample: 5 wafers overlap bending span length: 30mm
Crosshead speed: 5mm / min

From Table 4, when the resin bond wire saw (a1) and the resin bond wire saw (a2) are used, a wafer having a higher bending strength can be obtained as compared with the cutting by the electrodeposition method or the cutting by the free abrasive method.

The resin bond wire saw obtained by the present invention can be applied to a TFT substrate, a solar cell substrate, a compound semiconductor substrate, etc. from a single crystal or a polycrystalline ingot such as silicon, gallium arsenide, copper / indium / selenium (CIS). It is an indispensable tool for efficiently cutting out the wafer to be used simultaneously. 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 (5)

It is used for manufacturing a resin bond wire saw in which abrasive grains are fixed to the surface of a metal core wire through a resin bond,
Novolak type phenol resin 100 parts by weight Resole type phenol resin 10-30 parts by weight Amine-based silane coupling agent An adhesive composition for resin bond wire saws having 0.1-5 parts by weight as an essential component. Furthermore, the adhesive composition for resin bond wire saws of 5 containing 20-20 weight part of hardening | curing agents of a novolak-type phenol resin. The paste for resin bond wire saws containing the adhesive composition of Claim 1 or 2, the solvent of this adhesive composition, an abrasive grain, and the filler which consists of inorganic particles. Preparing the paste according to claim 3 and a metal core wire, applying the paste to the surface of the metal core wire,
The manufacturing method of the resin bond wire saw including the heating process which heats the apply | coated said paste with the infrared rays containing a near infrared ray, and carries out the crosslinking reaction of the said adhesive composition. Furthermore, a step of winding the wire obtained in the heating step to obtain a wound body,
The manufacturing method of the resin bond wire saw of Claim 4 including the reheating process which heats this winding body.

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