JP2014070277A - Wire for etching cut, and cutting method of inorganic brittle material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire for cut suitable for an etching cut method reducing wide cutting loss by abrasive grains of a saw wire, and to provide a cutting method of an inorganic brittle material using the same.SOLUTION: There are provided a wire for etching cut 2 constituted of a small diameter metal wire (Co alloy thin line) made of a Co alloy including, by mass%, Ni:12.0 to 20.0%, Cr:12.0 to 25.0%, Co:35 to 60%, and having high strength property with a bearing force of 1,500 to 2,200 N/mm2 with a wire diameter of 0.2 mm or less, a pitting potential property based on JIS-G0577 (V'c10):0.60 to 0.75 V and an electric resistivity of 80 to 110 μΩ cm (in the room temperature environment) for chemically cutting an inorganic brittle material by corrosion etching, and a cutting method of the inorganic brittle material by the wire.

Description

Detailed Description of the Invention

  The present invention relates to a wire for thin etching cut for use in cutting inorganic hard brittle materials such as semiconductor silicon, ceramic, quartz, and stone by a chemical method by corrosive etching, and inorganicity using the same The present invention relates to a method for cutting a brittle material.

  Conventionally, as a cutting method for cutting hard brittle materials such as stone, reinforced concrete, semiconductor silicon, ceramic, sapphire, and quartz, for example, high strength wire (saw wire) W such as piano wire and stainless steel wire as shown in FIG. A wire sawing method has been developed in which a workpiece is moved while being in sliding contact with a workpiece (workpiece) C at a high speed and is physically cut by grinding abrasive particles interposed around the workpiece. Various wafer products are obtained by hanging a workpiece in multiple stages at a relatively narrow equal interval of about 1 mm in thickness.

  The cutting process is performed by, for example, a free abrasive grain method in which cutting is performed while separately supplying the abrasive grains together with the high-strength wire rod W, or abrasive grains are previously deposited on the surface of the wire rod W by electrodeposition, adhesive, or the like. A method using a fixed-abrasive saw wire for fixing the wire is employed. In particular, the latter, which uses a fixed abrasive grain saw wire, is more indispensable for the current manufacturing process of semiconductor wafers because it can cut more efficiently.

  FIG. 7 shows a state of cutting by the saw wire, and shows an enlarged view in the cross-sectional direction. Saw wire is usually performed by continuously running while pressing the workpiece more strongly because it is necessary to increase its cutting efficiency. Therefore, the saw wire is applied with high strength tension so as to be suitable for its pressing strength and continuous running, and the core material is also made a relatively thick line of about 0.2 to 0.6 mm, for example. High strength is achieved.

  Further, the configuration is such that the high-strength core material and hard abrasive grains such as diamond and CBN are fixed to the surface thereof with a predetermined distribution density, and in order to make the abrasive grains more firmly fixed, A composite wire in which the surface of the material is preliminarily plated with metal is used, and the abrasive grains are suspended in, for example, a Ni plating solution for electrodeposition, and the abrasive grains are fixed simultaneously with the plating process (for example, Patent Documents 1 and 2)

  JP 09-150314 A   JP2007-203393A

  As described above, in the conventional cutting technique using the saw wires of Patent Documents 1 and 2, the abrasive grains are fixed through the core material having the predetermined wire diameter and the base plating layer applied to the surface thereof. Therefore, when the saw wire is used for cutting, the substantial cutting width is at least larger than the overall dimensions including these members. For example, even if a thin metal wire of about 0.2 mm is used as the core material, Depending on the grain size, the substantial cutting width is widened to, for example, about 0.3 to 0.4 mm, and eventually that portion disappears and a cutting loss occurs.

  In addition, the cut surface thus cut also varies depending on the size of the abrasive grains, but the formation of minute irregularities is unavoidable, and a polishing process is performed to further improve the surface properties. The yield associated with the processing is about 40 to 60%, which contributes to a decrease in the yield and cost increase of expensive workpieces.

  As measures for improving this, for example, it has been proposed to make abrasive grains finer or to make the core material thinner. However, when the abrasive grains are made finer, the cutting performance is lowered, and when the latter is made of a thin core material, the overall strength of the saw wire itself is lowered, and the pressing strength against the work is weakened or the wire travels. It is inevitable that a change in work conditions such as a reduction in speed and a reduction in efficiency associated therewith are unavoidable, and that the saw wire itself may be disconnected during the work cutting work.

  And if the saw wire breaks during the work, it will take a lot of effort to adjust the wire spanning set again, and the quality of the workpiece cut surface will also deteriorate the flatness and smoothness such as a step before and after that. . Therefore, a great burden is required such that an extra polishing process is required for the refurbishment, which greatly affects work efficiency and yield reduction.

  In recent research, a cutting method using a chemical corrosion etching phenomenon has been tried as a method capable of improving such a problem of the saw wire and cutting with a cutting width of only the wire. The object of the present invention is to provide a cutting wire that can be suitably employed in this etching cutting method and a method for cutting an inorganic brittle material using the same.

That is, the invention according to claim 1 of the present application is a cutting wire made of a thin metal wire for chemically cutting an inorganic brittle material by corrosion etching,
The metal wire is composed of a Co alloy containing Ni: 12.0 to 20.0%, Cr: 12.0 to 25.0%, and Co: 35 to 60% in terms of mass%, and the wire diameter is 0.00. Along with the high strength characteristics of proof stress 1500-2200N / mm2 at 2mm or less,
Pitting corrosion potential (V'c10) based on JIS-G0577: 0.60 to 0.75 V, and an electrical resistivity of 80 to 110 μΩ · cm (provided in a room temperature environment) (Co alloy fine wire) It is the wire for etching cut characterized by consisting of.

  Further, the invention according to claim 2 is that in which the electrical resistivity is 95 to 105 μΩ · cm, and the invention according to claim 3 is that the Co alloy fine wire is C: ≦ 0.30% in mass%. Si: ≦ 2.0%, Mn: ≦ 2.0%, Ni: 14.0-20.0%, Cr: 15.0-25.0%, Mo: 2.0-10.0%, Co : 40.0 to 55.0%, and it is a precipitation hardening type comprising the remainder Fe and inevitable impurities, and the invention according to claim 4 is characterized in that the Co alloy fine wire is C: 0. 08-0.20%, Si: ≦ 1.0%, Mn: ≦ 1.50%, Ni: 14.0-18.5%, Cr: 19.0-25.0%, Mo: 4.0 To 8.0% and Co: 40.0 to 55.0%, Al: 0.1 to 4.0%, Ti: 0.10 to 2.5%, Nb: 0.01 to 1.%. The wire for etching cut, characterized in that it is a precipitation hardening type Co alloy comprising 0% and W: 0.50 to 5.0%, and the balance Fe and inevitable impurities. is there.

    Further, in the invention according to claim 5, the Co alloy fine wire has a matrix whose main composition is at least one of Co, Mo, Al, Ti, Nb and W, or Al and / Alternatively, any precipitate of Ti or an intermetallic compound is formed, and in the invention according to claim 6, the precipitate has an average particle diameter of 0.02 to 0.2 μm in an arbitrary cross section of the alloy thin wire. And the carbide distributed in an area ratio of 0.5 to 2%, and the invention according to claim 7 has a surface roughness Ra of 0.01 to 0.5 μm, The invention according to No. 8 is a composite thin wire formed by braiding and / or twisting at least two of the Co alloy thin wires described above.

Further, the invention according to claim 9 is a cutting wire made of the Co alloy thin wire according to any one of claims 1 to 8, and when cutting the fracturing of the inorganic brittle material of the workpiece at an arbitrary cut surface,
The corrosive solution that corrodes and dissolves the workpiece by a corrosive etching phenomenon is interposed in the contact interface between the workpiece and the cutting wire, and the corrosive dissolution occurs only at the contact interface that contacts the cutting wire. An inorganic brittle material cutting method characterized by continuously cutting at a predetermined cutting speed and traveling speed while energizing and heating a cutting wire at a predetermined temperature.

  In the invention according to claim 10, the corrosive solution is any one of a hydrofluoric acid solution composed of 2 to 5% HF and 10 to 15% NO3, or a hydrofluoric acid solution of 2 to 7% HF and 15 to 20% H2SO4. The invention according to claim 11 is the above-described cutting method in which the heating temperature of the cutting wire is set to 50 to 85 ° C.

  It is the schematic explaining the etching cut technique which this invention makes object.   It is a principal part enlarged view of the workpiece | work cutting | disconnection by an etching cut.   It is an example of the microscope picture which shows the precipitation state of a precipitate.   Plan view of cutting wire showing other forms   It is a cross-sectional view of the wire for cutting which shows another form.   It is a perspective view which shows the workpiece | work cutting state by the conventional saw wire.   It is a cross-sectional view of a conventional abrasive grain fixed type saw wire.

1: Workpiece 2: Cutting wire 2A: Composite thin wire 3a: Corrosive solution

  Hereinafter, preferred embodiments of the etching cut wire of the present invention (hereinafter also simply referred to as “cut wire”) will be described together with the production method and the drawings. Among them, the composition of the Co alloy material means mass% unless otherwise specified in the text.

  The cutting wire 1 is composed of a Co alloy containing 12.0 to 20.0% Ni, 12.0 to 25.0% Cr, and 35 to 60% Co in mass%, and the wire diameter is 0.00. Along with high strength characteristics of 2 mm or less and proof stress 1500-2200 N / mm2, pitting corrosion potential characteristics (V'c1o) based on JIS-G0577: 0.65-0.75 V, 80-100 μΩ · cm under room temperature environment It consists of a thin line of Co alloy with electrical resistivity.

  The Co alloy conforming to this composition will be described in more detail. For example, in mass%, C: ≦ 0.30%, Si: ≦ 2.0%, Mn: ≦ 2.0%, Ni: 14.0. 20.0%, Cr: 15.0 to 25.0%, Mo: 2.0 to 10.0%, Co: 40.0 to 55.0%, the balance being Fe and inevitable impurities (No. One form), and also by mass%: C: 0.08 to 0.20%, Si: ≦ 1.0%, Mn: ≦ 2.00%, Ni: 12.0 to 12.0%, Cr: 19.0 to 25.0%, Mo: 4.0 to 8.0%, Co: 40.0 to 55.0%, Al: 0.1 to 4.0%, Ti: 0.10 -2.5%, Nb: 0.01-1.0% and W: Any one or more of 0.5-5.0%, comprising the remaining Fe and inevitable impurities (second form) Yes, These are both configured as a composition comprising a precipitation hardening capabilities. For example, NAS604PH is suitable for a Co alloy having the former composition, and the latter alloy is a CCW alloy, both of which are implemented as wires for high-strength springs.

  Co alloys having these compositions are excellent in cold workability compared to, for example, ordinary stainless steel wires, and can improve mechanical characteristics significantly by precipitation hardening after the processing, for example, several tens of μm. It is preferable that the diameter can be reduced to a fine wire of a certain level, and sufficient strength maintenance and corrosion resistance are provided, as well as energization characteristics suitable for the present invention.

  That is, the cutting method by the corrosive etching targeted by the present invention does not need to press the work (cut object) itself strongly or increase the cutting traveling speed as in the case of the conventional saw wire using abrasive grains. Since it can be set relatively loosely, it is possible to use a very fine thin wire having a wire diameter of less than 0.2 mm, preferably about 0.02 to 0.08 mm. In addition, the cross-sectional shape is not limited to a normal circular shape, but includes a non-circular shape such as a square line, and the wire diameter display in that case is a converted wire diameter calculated from the area of the arbitrary cross-section. It shall be indicated by

  In addition, since the Co alloy includes high Ni and high Cr and has excellent corrosion resistance, even when a highly corrosive solution such as hydrofluoric acid is used as the etching corrosion solution, substantial corrosion of the wire is caused. The weight loss is, for example, 3 g / m2 / hr. Since it is extremely small as described below and has no substantial influence, it has sufficient suitability for re-use for repeated use.

  As the corrosive solution, as described above, a strong corrosive solution such as hydrofluoric acid or hydrosulfuric acid that can corrode and dissolve only a necessary part of the work can be adopted, and the cut is chemically cut by the corrosive etching phenomenon. It is. Further, in the present invention, the wire is heated to about 50 to 200 ° C., for example, so that the corrosion etching reaction occurs only in the vicinity of the contact interface in contact with the wire. Co alloys may have properties suitable for such usage.

  That is, the inorganic brittle material of the workpiece has a specific active reaction temperature range according to its type, and causes the most active corrosion reaction in an environment above that temperature, but conversely in a low low temperature range, It does not lead to a corrosive reaction and maintains the original surface state. For example, when the silicon is used as a workpiece, the active temperature range is 50 ° C. or higher, and the sapphire is 70 ° C. or higher. However, if the temperature is higher than necessary, the surrounding environment may be adversely affected by vaporization of the solution. From, for example, 85 ° C. or less.

  Therefore, by appropriately setting the amount of heat generated to be applied to the cutting wire according to the activation temperature of the corrosive solution, it is heated to an appropriate temperature required for fusing cut, and the corrosion existing around the wire The solution is adjusted so as to be more active. In that case, if a corrosive solution exists in a part other than the cutting part of the workpiece, a slight corrosion reaction occurs, but the degree is not as great as the corrosion reaction in the cutting part, and cannot be quantified as a corrosion weight loss. In this sense, in the present invention, corrosion dissolution is expressed as “occurs only at the contact interface” where the wire contacts, but also includes the meaning of “preferentially corrodes the contact interface”. .

With respect to such usage, the reason why the Co alloy is suitable for the practice of the present invention is that the Co alloy has the following characteristics.
(1) It has a ductility and toughness that can be easily processed to a thin wire such as a fiber, and has high wire drawing workability.
(2) As a material property, it has high strength and mechanical properties excellent in fatigue properties and elastic properties, so that it can be used as a wire having a smaller diameter. By these (1) and (2), the cutting loss of the workpiece can be reduced.
(3) Also, as a measure to further improve the mechanical properties, it can be used as a precipitation hardening type alloy wire that improves the properties by aging treatment after processing a small diameter.
(4) Excellent corrosion resistance even in strong corrosive solutions such as hydrofluoric acid solution and in such environments.
⇒ This makes it possible to reuse the wire.
In addition, the corrosion resistance is indicated by “pitting corrosion potential” based on JIS-G0577 in the present invention, and the Co alloy has a corrosion resistance of 0.60 to 0.75 V, and can have a corrosion resistance higher than that of stainless steel. Can be reused as an industrial wire. Although the JIS-G0577 standard is intended for stainless steel, the Co alloy of the present application can be measured in the same manner, so that it is used.
The measurement conditions were 3.5% NaCl solution (30 ° C.), Ar deaeration and a sweep rate of 20 mV / min. And the reference electrode is Ag / AgCl.
(5) The matrix of the Co alloy has a high electrical resistivity and can be easily heated to a predetermined temperature by energization or the like, thereby contributing to reduction of energy efficiency.
For example, it has a high electrical resistance of 80 to 110 μΩ · cm even in a relatively low temperature environment of about normal temperature, and its heat generation characteristics are further improved by the precipitation hardening type precipitates precipitated by precipitation hardening functions such as aging treatment. Co alloy can be used.
(6) The mechanical properties such as the strength of the wire itself are not substantially lowered even when heated to about 200 ° C. by the energization treatment.

    As for the precipitate accompanying the precipitation hardening treatment, carbide, Al and / or Ti intermetallic compound mainly containing any one or more of Co, Mo, Al, Ti, Nb or W in the matrix. Any of those in which a precipitate is formed is included. The precipitate includes, for example, the fine precipitate having an average particle diameter of about 0.02 to 0.2 μm in a matrix matrix and 0.5 to 2.0 by microscopic observation in an arbitrary cross section of the Co alloy. It is recommended to use a volume ratio (area ratio) of%. The verification can be observed, for example, at a high magnification of about 1000 times or more, and can be quantified by performing image diffraction.

  In this case, the average particle diameter is indicated by an average value obtained by dividing the total of the major 20 major diameters of the precipitated particles confirmed in the measurement field by the number of measurement points, and the volume ratio is similarly measured in the predetermined field of view. This means the area ratio occupied by the precipitated particles to be verified by the magnification. This increases the current resistivity of the wire itself and contributes to the improvement of strength as a thin wire material. FIG. 3 shows a distribution state of carbide particles having an average particle diameter of 0.04 to 0.10 μm and a volume ratio of 0.5 to 1.0% as an example of a more preferable precipitate. Includes some irregularities.

  The Co alloy fine wire is premised on use in a temperature range of, for example, room temperature to 200 ° C., and has a high electric resistance characteristic of 80 to 110 μΩ · cm, for example, in a room temperature environment of 20 ° C. What has is adopted. The measurement can be performed using a test piece extracted arbitrarily, for example, by a method using a potentiometer of JIS-C3002 “Testing method for electrical copper wire and aluminum wire”. If the characteristic value is less than 80 μΩ · cm, A large amount of electrical energy is required to heat to the heat generation temperature by energization when using the battery, which is not efficient. On the other hand, if it exceeds 110 μΩ · cm, it is difficult to obtain with the Co alloy, and more preferably 95 to 105 μΩ · cm.

  As a method for arbitrarily adjusting the electrical resistivity, for example, it is recommended to adjust the Co content to be relatively high or to reduce the working strain accompanying cold working. Moreover, it can also raise more by the said deposit deposited by precipitation hardening functions, such as the said aging treatment. In order to have this function, in the present invention, the Co alloy is desirably a precipitation hardening type.

  Next, the cutting process according to the present invention will be described. As shown in FIG. 1, an inorganic brittle material (for example, ingot) such as silicon, sapphire, and ceramics having various compositions is used as a work 1, and a cutting portion 4 thereof. The cutting wire 2 having the above-described configuration is stretched along the wire and is cut while maintaining a constant cutting speed (arrow A) and traveling speed. It is characterized by being performed by.

    That is, the cutting wire 2 fed out from the supply reel 10 is cut and cut gradually by being brought into contact with the workpiece 1 through various rolls, and then the corrosive solution remaining on the surface is passed through the washing tank 11 and the drying heater 12. It is removed and dried, and taken up on the take-up reel 13. In that case, the wire 2 can be cut over the workpiece 1 repeatedly or in multiple stages, as indicated by a one-dot chain line in FIG.

  FIG. 2 is an enlarged view of the main part in the vicinity of the workpiece 1. The cutting wire 2 fed from the supply side is placed on the surface of the workpiece 1 by the corrosive solution supply means 3 provided at the front stage of the workpiece 1. The solution is applied and encapsulated and sent to the cutting portion 4 of the workpiece 1, and the corrosive solution 3 a is interposed at the contact interface, thereby causing a local corrosion etching reaction at the cutting portion 4. In FIG. 1, the corrosive solution 3 a is configured such that, for example, a felt 3 </ b> A is provided below a container containing the corrosive solution 3 </ b> A, and the corrosive solution 3 a can be applied on the surface of the cutting wire 2 that travels by capillary action. It is used for the cutting part. If necessary, it can be applied to the wire surface by passing through the solution storage tank.

  In addition, the cutting wire 2 is configured to be electrically heated by the current heating mechanism 14 (guide rolls 14A and 14B) provided before and after the workpiece 1 so that the corrosion etching reaction occurs only at the necessary portion of the cut. In addition to heating to a predetermined temperature that can be reacted (for example, 50 to 200 ° C.) according to the set current amount, and adjusting the cutting speed with respect to the work 1 and the traveling speed of the wire 2 to have a constant relationship, 1 is continuously cut. Reference numeral 15 denotes a power source for heating the wire 2 to a predetermined temperature.

  According to the present invention, the wire 2 for cutting the workpiece 1 has a substantially predetermined temperature in the set region, and can actively cut the workpiece 1 by a corrosive etching reaction so that the cut cut surface is smooth. And flatness can be secured. On the other hand, even if the corrosive solution remains other than the cut portion, since there is no heating by the wire in that portion, no substantial corrosion reaction occurs.

  As the corrosive solution, for example, a highly corrosive solution such as the above-mentioned exemplified hydrofluoric acid or hydrosulfuric acid can be adopted, and the corrosive etching reaction at a more optimum temperature can be performed by changing the composition ratio. The generation temperature can be changed. According to the inventor's study, when the volumetric mixture ratio of HF and NO3 is 1: 5 in the hydrofluoric acid solution, the reaction initiation temperature of the reaction is about 65 ° C., whereas the ratio 1: 4 is about At 59 ° C., similarly 1: 3, about 54 ° C., the result of temperature change with the blending ratio was obtained. Therefore, optimal implementation is performed by appropriately setting the type of workpiece and the composition of the corrosive solution.

  Next, the effect of each composition constituting the Co alloy in the present invention and the reason for the amount will be described.

<< Ni: 12.0 to 20.0% >>
[Ni] is an element that is necessary for making the substrate into a stable austenite structure, and is effective in improving the processability by promoting the oxidation resistance of chromium. When the Ni content is less than 12.0%, it is difficult to secure the corrosion resistance required by the present invention, and it is difficult to expect a sufficient effect. When the Ni content exceeds 20.0%, it is difficult to improve the strength for the cost. More preferably, it is 14.0 to 20.0%, and in the case of adding a third additive element described later, it is preferably 14.0 to 18.5%.

<< Cr: 12.0-25.0% >>
[Cr], like Ni, improves the corrosion resistance and mechanical properties by dissolving in the dough of the alloy material, and generates precipitates such as chromium oxide in the matrix by the heat treatment, It works to increase base strength and electrical resistance. The effect is obtained, for example, at 12.0% or more. On the other hand, if it exceeds 25.0%, the forgeability is affected and the fatigue characteristics are lowered. Therefore, it is preferably 15.0% or more, more preferably 19.0%.

<< Co: 35-60% >>
As described above, [Co] corresponds to a basic element in the present invention, and in this embodiment, it influences the electrical resistivity by its composition. It is preferable to set it to 40.0 to 55.0% when it contains about several percent Mo as the other additive composition and the composition.

  In addition to these basic compositions, the Co alloys include those containing the following additional elements as the alloys of the first and second forms.

<< C: ≤0.30% >>
The addition of [C] is effective for making crystals finer and adding mechanical properties, particularly high strength. However, if it is added in a large amount exceeding 0.30%, an excessive amount of carbide is formed, which tends to cause problems in workability when reducing the diameter and fatigue life associated with repeated bending. More preferably, it is 0.08 to 0.20%.

<< Si: ≤ 2.0% >>
[Si] is a deoxidizing component necessary for melting, and its addition improves fatigue, strength, and life characteristics. However, if it exceeds 2.0%, the creep characteristics deteriorate and it is easy to cause σ phase formation. More preferably, it is 1.0% or less (for example, 0.1 to 1.0%).

<< Mn: ≦ 2.0% >>
[Mn] improves hot workability together with nickel. However, generally, even if it exceeds 2.0%, the effect is saturated and the cost is increased. Therefore, the content is more preferably 1.50% or less (for example, 0.2 to 1.50%).

<< Mo: 2.0-10.0% >>
[Mo] drastically improves the strength of this alloy, and exhibits the most excellent effect at 2.0 to 10.0%. However, particularly those exceeding 10% tend to be hard and brittle and shorten the life, and more preferably 4.0 to 8.0%.

The present invention also allows the addition of the following specific third element to each Co alloy for the purpose of further improving the mechanical properties.
The third element includes Al: 0.1-4.0%, Ti: 0.10-2.5%, Nb: 0.01-1.0% and W: 0.50-5.0% Any one or more of these may correspond, and characteristics can be improved by aging characteristics due to the precipitates of these compositions. The addition of the third element is preferable because the same effect can be seen in the Co alloy of the first form, or in particular a Co alloy that does not define an additive element such as C or Si.

  When each composition of the third element is individual, the effect cannot be expected if it is less than the above lower limit value, and conversely if it exceeds the upper limit, the hardening of the material will increase and the workability will be reduced. . Moreover, in the case where any two or more are added in combination, it is preferable that the total does not exceed 5.5%.

  Among them, [W] has the advantage of giving non-magnetism as well as improving the corrosion resistance and fatigue strength by giving the fabric strength by being dissolved in Co similarly to Mo. The effect is seen with addition of 0.50% or more, but when it exceeds 5.0%, a second phase of a different quality is likely to precipitate and become brittle, and more preferably 3.0% or less. For example, when Mo and W are used in combination, the total content is preferably 3.0 to 10.0%. In addition to these constituent elements, other impurities such as P and S are 0%. The inevitable content of 0.05% or less is allowed, and the balance is Fe.

The cutting wire 1 of the present invention configured as described above can be manufactured by the following method, for example.
Using the ROD wire of Co alloy adjusted to the above composition, while performing wire drawing and heat treatment repeatedly, the final processing rate, for example, 75% or more (more preferably 85 to 99.5%) is strongly processed, and the target line After finishing wire drawing to a diameter, an aging heat treatment is further performed in a temperature range of 400 to 650 ° C. The former wire drawing is more preferably performed by wet wire drawing using a diamond die, and the average roughness Ra is preferably finished to a surface state of 0.01 to 0.5 μm. The surface roughness appropriately changes depending on the total processing rate, the type of lubricant used, and the viscosity, and has the surface roughness so that the corrosive solution is retained when this is used as a cutting wire. Can increase sex. Further, the latter aging heat treatment conditions can also promote the formation of precipitates that precipitate in the matrix matrix, and can improve the current-generating heat generation. As a more preferable heat treatment condition, it is recommended to heat at a temperature of 500 to 600 ° C. × time for about 3 to 10 minutes and to cool rapidly.

  FIG. 4 is a plan view showing another form of the cutting wire. This is, for example, a combination of a plurality of Co alloy fine wires having the above-mentioned characteristics, or, at the material stage, a plurality of wires are preliminarily converged and the diameter is reduced by a converging wire drawing method that simultaneously reduces the diameter. About 2 to 100 (two in this embodiment) thread-like composite wire can be used as a twisted wire or a braided composite thin wire 2A obtained by winding the wire-like composite wire at a predetermined pitch. In this state, the wire surface is covered with the corrosive solution 3a. Similarly, FIG. 5 shows a cross-sectional view of FIG. 4, and a liquid reservoir 16 due to capillary action is seen in the adjacent portion between the wires, which can provide a sufficient supply of corrosive liquid.

Specifically, each single wire 2c is formed as an extra fine wire having a wire diameter of about 0.005 to 0.05 mm and twisted at a predetermined pitch (for example, about 3 to 100 times the wire diameter of the core wire 2c). It is composed.
Hereinafter, the present invention will be further described by way of examples.

  As an example, as a criterion for evaluating the suitability of the material composition, in order to see the effect of other additive elements on the three elements of Ni, Cr, and Co, the amount of each component composition was changed stepwise. The seven types of Co alloy wires described were prepared. Then, using the soft wire rod (wire diameter: 0.18 mm), it is set in a wet cold wire drawing machine, and ultra-fine wire drawing is performed with a target of a total working rate of 89% to 0.06 mm hard wires. The workability was evaluated. In the table, the underlined element column of each sample indicates that it is outside the composition range of the present invention.

    Moreover, the normal stainless steel wire (SUS304, SUS316, SUS430) was used for the comparison material, and the same wire drawing process was performed according to the above to obtain the hard thin wires of comparisons 1 to 3.

  The wire drawing is performed by immersing a diamond die in a liquid using non-chlorine oil (melt viscosity: 16 mm 2 / S (40 ° C.), setting a working rate between the dice to 12 to 20%, and a wire drawing speed of 200 m. / Min., And the surface defects (for example, occurrence of surface abnormalities such as dice marks and flaws) of the obtained fine wires and the presence or absence of disconnection were investigated, and the results are shown in Table 2.

  As a result, the samples 1, 5, and 7 and the comparative material 3 were all disconnected and dice marks were generated, and the target wire diameter of 0.06 mm could not be obtained.

  Next, regarding the corrosion resistance of each sample, the pitting corrosion potential according to JIS-G0577 was determined for each of the drawn samples, and 35% NaCl was used as the target liquid, Ar deaeration, and the sweep rate was 20 mV / min. It was done in. As a result, sample 6 did not show sufficient corrosion resistance, and as a result, samples 2 to 4 according to the present invention were most stable.

  In light of the above results, the Co alloy according to the invention of the present application is superior to those comprising Ni: 12.0 to 20.0%, Cr: 12.0 to 25.0%, and Co: 35 to 60%. Differences were noted. Accordingly, other characteristics of the Co alloy shown in Table 2 were evaluated as a more detailed verification of other trace components within the range.

  For the processing of these samples A to D, for the purpose of further reducing the diameter compared to Example 1, a soft wire rod of 0.18 mm is used, and a 0.03 mm thin hard wire is manufactured by the same wet wire drawing. did. All the sample materials were confirmed to have good workability.

Next, the strand type continuous aging heat treatment is further performed on the hard thin wire, and the heating conditions are set to a temperature of 500 to 550 ° C. and a product of temperature × time (min.) As 18000 to 30000. The atmosphere was performed in an Ar gas having a dew point of −60 ° C.
Table 3 lists the characteristic results of the obtained thin wires.

  In the above test, the mechanical properties are based on JIS-Z2241, and the tensile test is performed at a distance between the gauge points of 100 mm. The precipitates are observed by a microscope magnified 1000 times with respect to the cross section of each thin wire. For each particle found in the measurement field of view, the results of the top 20 points of the average diameter are shown as average particle diameters that are further averaged, and are obtained by image analysis together with the distribution ratio.

Corrosion resistance is determined according to the pitting potential according to JIS-G0577, and electrical resistivity is determined according to JIS-C3002 “Testing method for electrical copper wire and aluminum wire”. The electric resistance value at 50 cm is shown as an average value. The test environment was a room temperature environment at a temperature of 20 ° C.
In particular, it was confirmed that a sample having a fine compound precipitate as shown in FIG.

  In addition, each of the obtained thin wires has a brilliant surface state, and the surface roughness Ra is 0.03 to 0.14 μm. There was no processing trouble such as marks, and it had good small diameter workability.

  Example 3 shows the result of a cutting test using the Co alloy fine wire obtained in Example 2, and the workpiece is cut so that a sapphire ingot (diameter 2 inches) can be cut into a thin plate with an interval of about 1 mm. A thin alloy wire was passed in multiple stages, and a cutting test was performed under the following conditions: cutting at a constant speed and feeding speed of the cutting wire.

  At that time, according to FIG. 2, the corrosive solution is set to adhere to the wire surface in the previous stage of the work so that a predetermined part of the work is cut, and the cutting amount is 0.12 μm / min. And it was performed on the conditions of traveling speed 3m / min. Further, as the corrosive solution, a 5% HF + 15% HNO3 hydrofluoric acid solution is used, so that the corrosive etching reaction can be promoted only at a necessary portion of the cutting treatment, and a current of 25 A / dmm2 is applied and energization heating is performed so that the liquid temperature of the wire contact portion becomes 80 ° C.

  The corrosive solution was able to improve the wettability of the solution due to unevenness between microscopic crystal grains formed on the surface of the fine wire, resulting in a corrosive solution sufficient for the cutting treatment.

  In the cutting and cutting test, although each cutting wire was 30 μm and a fine thin wire, there was no need to apply pressure more than necessary to the workpiece, and troubles such as wire breakage during the cutting test were not observed. In this test, the workpiece can be cut and cut in a short time of about 200 to 240 minutes, and the cut width remains below 1.5 times the wire diameter of the wire, yielding a smooth and smooth surface state. It was.

  In order to further evaluate the applicability of the sample B Co alloy thin wire (wire diameter 0.08 mm) to different types of workpieces, a hydrofluoric acid solution was used as the corrosive solution, and the workpiece was a polycrystalline silicon ingot (thickness). The applicability to 8 inches) was verified under the same conditions. A silicon ingot easily undergoes a corrosion reaction at the cut portion heated by the cutting wire, while the corrosion solution on the wire surface does not reach the active temperature range in areas other than the cut portion, leading to a sufficient corrosion reaction. It was confirmed that there was almost no effect. From this, it was recognized that it could be sufficiently employed for cutting of the same inorganic brittle material. In addition, the size of the cut width was very fine of 0.15 mm or less, and a yield of 70% was possible.

  As the next example, in the same manner as used in Example 4, three Co alloy thin wires (wire diameter 0.14 mm) of Sample B were prepared, and these were set in an ultra-fine stranded wire machine and twisted. A similar cut test was also performed on a composite fine wire cutting wire twisted at a pitch of 0.2 mm.

  In this embodiment, the reservoir 16 of the corrosive solution as shown in FIG. 5 can be confirmed in the recess where the alloy fine wires are adjacent to each other, and this is effective by enhancing the effective storage effect by capillary action. In addition, in this embodiment, the spiral contact portion of the composite thin wire has a sufficient liquid reservoir in the recess, and a good cutting process can be performed.

Industrial application fields

  According to the wire for etching cut of the present invention, the cutting cut can be substantially reduced without interposing abrasive grains at the cutting interface as in the prior art, and the wire can be cut by applying relatively loose tension. Therefore, it can be widely used for cutting various inorganic brittle materials such as silicon, sapphire and ceramic.

Claims (11)

A cutting wire made of a thin metal wire for chemically fusing and cutting inorganic brittle materials by corrosive etching,
The metal wire is composed of a Co alloy containing Ni: 12.0 to 20.0%, Cr: 12.0 to 25.0%, and Co: 35 to 60% in terms of mass%, and the wire diameter is 0.00. Along with the high strength properties of less than 2mm and proof strength 1500-2200N / mm2,
Pitting corrosion potential (V'c10) based on JIS-G0577: 0.60 to 0.75 V, and an electrical resistivity of 80 to 110 μΩ · cm (provided in a room temperature environment) (Co alloy fine wire) Etching cut wire, characterized by comprising:   The wire for etching cut according to claim 1, wherein the electrical resistivity of the Co alloy fine wire is 95 to 105 µΩ · cm.   Co alloy fine wire is C: ≦ 0.30%, Si: ≦ 2.0%, Mn: ≦ 2.0%, Ni: 14.0-20.0%, Cr: 15.0-25 in mass%. 0.0%, Mo: 2.0 to 10.0%, Co: 40.0 to 55.0%, and the precipitation-hardening type Co alloy consisting of the remaining Fe and inevitable impurities. Item 3. An etching cut wire according to Item 1 or 2.   Co alloy fine wire is C: 0.08-0.20%, Si: ≦ 1.0%, Mn: ≦ 2.0%, Ni: 14.0-18.5%, Cr: 19. 0-25.0%, Mo: 4.0-8.0%, and Co: 40.0-55.0%, and Al: 0.1-4.0%, Ti: 0.10-2 0.5%, Nb: 0.01 to 1.0%, and W: 0.50 to 5.0%, and the precipitation-hardening type Co alloy composed of the remaining Fe and inevitable impurities. The wire for etching cut according to claim 1 or 3, wherein   The Co alloy fine wire is a precipitate of either a carbide mainly comprising any one or more of Co, Mo, Al, Ti, Nb or W, or an intermetallic compound of Al and / or Ti in the matrix matrix. The wire for etching cut according to any one of claims 1 to 4, wherein is formed.   6. The precipitate is an carbide having an average particle diameter of 0.02 to 0.2 [mu] m and an area ratio of 0.5 to 2.0% in an arbitrary cross section of the alloy thin wire. The wire for etching cut as described.   The surface roughness Ra is 0.01-0.5 micrometer, The wire for etching cuts in any one of Claims 1-6.   A composite wire for etching cut, which is a single composite thin wire formed by braiding and / or twisting at least two Co alloy thin wires according to any one of claims 1 to 7. In cutting wire made of Co alloy fine wire according to any one of claims 1 to 8, when cutting the frangible inorganic brittle material of the workpiece at an arbitrary cut surface,
The corrosive solution that corrodes and dissolves the workpiece by a corrosive etching phenomenon is interposed in the contact interface between the workpiece and the cutting wire, and the corrosive dissolution occurs only at the contact interface that contacts the cutting wire. A method for cutting an inorganic brittle material, wherein the cutting wire is continuously cut at a constant cutting speed and a traveling speed while being electrically heated to a predetermined temperature.   10. The cutting method according to claim 9, wherein the corrosive solution is a hydrofluoric acid solution composed of 2 to 5% HF and 10 to 15% NO3, or a hydrofluoric acid solution based on 2 to 7% HF and a 15 to 20% H2SO4 solution. .   The cutting method according to claim 9 or 10, wherein the heating temperature is set to 50 to 85 ° C.