JP2012210664A - Wire electrical discharge machining device, wire electrical discharge machining method, method for manufacturing thin plate, and method for manufacturing semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a wire electrical discharge machining device in which deterioration in machining accuracy and machining speed that are caused by shirt circuits and a decrease in the frequency of electrical discharge are improved.SOLUTION: The wire electrical discharge machining device includes: a wire electrode 2 having a plurality of cut wires 2a each facing a workpiece 8 while being spaced apart from each other in parallel; a machining power supply 6 for generating a pulsed machining voltage; a plurality of power feed elements 7A, 7B electrically connected to the plurality of cut wires and applying the machining voltages between the plurality of cut wires and the workpiece to generate electrical discharge; a nozzle 80 which ejects treatment liquids along the plurality of cut wires toward a plurality of cut grooves formed in the workpiece by the electrical discharge, and in which ejecting holes through which the plurality of cut wires can pass are formed so as to face the workpiece; and a treatment liquid guide 100 provided on the workpiece while coming into contact with the workpiece and having a plurality of slits 101 each opened toward the workpiece and accommodating each of the plurality of cut wires one by one.

Description

  In the present invention, a wire electrode is wound between a plurality of guide rollers, the wire electrodes are arranged in parallel, and an electric discharge is generated between the parallel wire electrodes and the workpiece. The present invention relates to a wire electric discharge machining apparatus that cuts out a plurality of plate-like members.

  When slicing a thin plate from a columnar workpiece by wire electric discharge machining, a number of cutting wire portions are formed by winding one wire electrode between a plurality of guide rollers and arranging them in parallel. For example, Patent Document 1 proposes a method for improving the productivity of slicing processing on a workpiece by individually feeding power to the wire portion and simultaneously generating electric discharge between each cutting wire portion and the workpiece. .

  In the electric discharge type wire saw configured as described above, when electric discharge machining progresses and a plurality of cutting grooves for simultaneously cutting the workpiece are formed in the workpiece, machining caused by electric discharge machining is performed. It becomes difficult for waste to be gradually discharged out of the cutting groove and stays in the cutting groove. Since electric discharge is also generated for the machining waste staying in the cutting groove, if there is a lot of machining waste inside the cutting groove, particularly between the cutting wire portion and the work surface of the workpiece, the machining direction The frequency of discharge generated in the process decreases and the machining speed decreases.

  Moreover, since it becomes difficult for the processing liquid to reach the cutting wire portion gradually, there arises a problem that wire breakage is likely to occur due to poor cooling of the cutting wire portion. Therefore, by supplying the machining fluid to the machining part using a nozzle, the machining waste generated by electric discharge machining is discharged out of the cutting groove so that the machining waste does not stay between the electrodes, and the cutting wire part is cooled. The technique to do is disclosed by patent document 2, for example.

  According to the technique disclosed in Patent Document 2, even when the electric discharge machining by the plurality of cutting wire portions proceeds and the plurality of cutting grooves are formed deep, the tips of the plurality of cutting grooves, In order to ensure that the machining fluid can be supplied to the gap, the machining waste is discharged from the gap, and stable electric discharge machining by the cutting wire portion can be continued. However, when starting to cut the workpiece from the end surface of the workpiece, the entire nozzle outlet is not completely covered by the workpiece, so that the workpiece from the outlet not covered by the workpiece is not covered. Since the resistance is less, the machining liquid is likely to be ejected from the ejection port not covered with the workpiece.

  For this reason, the flow of the machining liquid is disturbed in the vicinity of the end face of the surface to be processed, and the cutting wire portion is vibrated by such a machining liquid and is easily short-circuited. Therefore, since electric discharge machining is unstable, when machining is started from the end face of the workpiece, machining must be performed at a slower machining speed. For example, the cutting wire portion is opposed to the workpiece at a position separated by several hundred μm to several mm from the end surface of the workpiece to be processed before the processing is started. Therefore, the nozzle through which the cutting wire portion passes in the vicinity of the center thereof is in a state in which about half of the nozzle outlet of the nozzle protrudes from the end surface of the workpiece to be processed.

  Since the workpiece is disposed so as to face the side surface of the workpiece with a gap of several tens of μm to several hundreds of μm with respect to the jet port, the workpiece is further provided with a groove by electric discharge machining. Since it has not been formed yet, most of the processing liquid ejected from the nozzle outlet toward the workpiece at this time is ejected from a portion of the nozzle that is not covered with the workpiece. Therefore, originally, it is desired to eject the machining liquid along the cutting wire portion, but the flow direction of the machining liquid is disturbed.

  Further, since the cutting groove is not yet processed to a sufficient length, the rectifying effect due to the machining liquid passing through the cutting groove is small, and the cutting wire portion is vibrated by the machining liquid whose flow direction is disturbed. As a result, the distance between the work surface of the workpiece and the cutting wire portion varies, and the state in which the cutting wire portion approaches the processing surface of the workpiece and the state in which the cutting wire portion is too far from the processing surface are repeated. .

  Therefore, the occurrence of discharge becomes intermittent, the effective discharge is reduced, and the machining efficiency is lowered. In such a machining situation in which the cutting wire portion becomes oscillating, if the value related to the electric discharge machining energy such as applied voltage, machining current, and discharge frequency is large, the cutting wire portion is short-circuited when it is short-circuited on the machining surface. Makes it easier to break. For this reason, for example, Patent Document 3 discloses a technique that suppresses wire vibration caused by a machining fluid flow near the machining end surface of a workpiece and stabilizes electrical discharge machining by using a wire electrode guide. .

JP 2000-94221 A PCT / JP2010 / 060686 Japanese Utility Model Publication No. 61-20227

  However, according to the above-described conventional technique, for example, the technique disclosed in Patent Document 3, in the ordinary wire electric discharge machining that forms one cutting groove with one wire electrode, the processing side of the workpiece is processed. The wire electrode guide mounted on the side surface suppresses wire vibration caused by the machining liquid and stabilizes electric discharge machining. However, in the disclosed wire electrode guide, since the flow path of the processing liquid is formed only in the wire traveling direction, the nozzle that is normally arranged in close contact with the workpiece in the up-down direction is provided from the wire electrode guide. Since the discharge port of the machining liquid supplied to the wire electrode guide is blocked, it becomes difficult for the machining liquid to be replaced in the wire electrode guide.

  Furthermore, when the machining liquid continues to be ejected from the nozzles arranged above and below into the wire electrode guide, and the machining liquid is filled in the wire electrode guide, the wire electrode guide has another discharge port for the machining liquid. Since there is no, it becomes difficult to replace the machining fluid in the wire electrode guide. In such a state, cooling of the wire electrode during electric discharge machining becomes insufficient, and the wire electrode is easily disconnected. Further, since the machining fluid is not easily replaced, the machining waste generated between the electrodes by the electric discharge machining is difficult to be discharged to the outside, and the electric discharge machining becomes unstable because it is easily short-circuited. Therefore, even in the electric discharge machining with a plurality of cutting wire portions targeted by the present invention, the wire electrode guide disclosed in Patent Document 2 is in the same machining state at the end face machining of the workpiece, and the wire is easily broken. However, since electric discharge machining becomes unstable, it does not solve the problem that the machining speed cannot be increased.

  Further, the magnitude relation between the hole of the wire electrode guide and the machining liquid jet nozzle of the nozzle used and the magnitude relation between the nozzle used by the wire electrode guide body and the machining liquid jet outlet relate to the supply state of the machining liquid. That is, due to the above-described size relationship, the machining fluid flows out of the wire electrode guide and is not sufficiently supplied into the wire electrode guide, or even if supplied into the wire electrode guide, the wire is vibrated. The technique disclosed in Document 3 does not mention such a relationship.

  The present invention has been made in view of the above, and a wire electrical discharge machining apparatus, a wire electrical discharge machining method, a thin plate manufacturing method, and a wire electrical discharge machining method capable of improving a reduction in machining accuracy and machining speed due to a short circuit and a decrease in discharge frequency An object is to obtain a semiconductor wafer manufacturing method.

  In order to solve the above-mentioned problems and achieve the object, the present invention generates a wire electrode having a plurality of cutting wire portions facing each other while being spaced apart from each other in parallel and a pulsed machining voltage. A power source for processing, and a plurality of electric power supplies that are electrically connected to the plurality of cutting wire portions and that generate a discharge by applying the processing voltage between the plurality of cutting wire portions and the workpiece And a discharge port through which a plurality of cutting wire portions can pass and a processing liquid is ejected along the plurality of cutting wire portions toward a plurality of cutting grooves formed in the workpiece by the discharge. A nozzle formed so as to face the workpiece, and a plurality of nozzles that are provided in contact with the workpiece and open toward the workpiece, and each of the cutting wire portions can be accommodated one by one. Has a slit Characterized in that it comprises a that working fluid guide portion.

  According to the present invention, even when a workpiece is machined from its end face by a plurality of cutting wire portions arranged in parallel, it becomes easy to stabilize the flow of the machining liquid, and vibration of the cutting wire portion can be suppressed. Stable electric discharge machining can be performed. Even when machining is started from the end face of the work piece, the flow rate and pressure of the working fluid can be increased, and the electric discharge machining energy can be increased. Therefore, machining near the end face and machining conditions inside the work piece are possible. Therefore, it is possible to suppress a decrease in processing accuracy and processing speed.

FIG. 1 is an overall perspective view of the wire electric discharge machining apparatus according to the first embodiment. FIG. 2 is a front view of the nozzle according to Embodiment 1 as viewed from the ejection port side. FIG. 3 is a plan sectional view of the nozzle as viewed from the direction perpendicular to the plane formed by the cutting wire portion according to the first embodiment. FIG. 4 is a front cross-sectional view of the nozzle portion showing a cross section parallel to the cut surface in the process of cutting the workpiece according to the first embodiment. FIG. 5 is a perspective view of the machining fluid guide section in the process of cutting the workpiece according to the first embodiment. FIG. 6 is a three-view diagram including a top view, a side view in the wire travel direction, and a side view from the other side of the machining fluid guide unit according to the first embodiment. FIG. 7 is a three-view diagram including a top view of a set of machining fluid guides provided in the wire electrical discharge machining apparatus according to the second embodiment, a side view in the wire travel direction, and a side view from the other side. FIG. 8 is a three-view diagram including a top view of a modified example of the machining liquid guide portion provided in the wire electric discharge machining apparatus according to Embodiment 2, a side view in the wire travel direction, and a side view from the other side. FIG. 9 is a partially enlarged perspective view of a machining liquid guide portion provided in the wire electric discharge machining apparatus according to the third embodiment. FIG. 10 is a partially enlarged perspective view of a modified example of the machining fluid guide provided in the wire electric discharge machining apparatus according to the third embodiment.

  Embodiments of a wire electric discharge machining apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
The configuration and operation of Embodiment 1 of the present invention will be described below. FIG. 1 is a perspective view showing a wire electric discharge machining apparatus according to the first embodiment.

  In the wire electric discharge machining apparatus according to the first embodiment, one wire electrode 2 fed out from the wire bobbin 1 is sequentially wound between the plurality of guide rollers 3a to 3d a plurality of times at a minute interval. A plurality of cutting wire portions 2a are formed by being rotated. That is, the wire electrode 2 has a plurality of cutting wire portions 2a. The interval between the cutting wire portions 2 a formed by winding the wire electrode 2 is the processing width (thickness) of the workpiece 8. That is, while the workpiece 8 is disposed facing the respective cutting wire portions 2a with a predetermined distance therebetween, a voltage is applied between each cutting wire portion 2a and the workpiece 8 while the workpiece 8 is being applied. By cutting and feeding the workpiece 8 to each cutting wire portion 2a, the workpiece 8 is discharged and cut at each cutting wire portion 2a.

  Thereby, the workpiece 8 is processed into a plurality of thin plates. The workpiece 8 is obtained by slicing a material into a plurality of thin plates. For example, a metal such as tungsten or molybdenum serving as a sputtering target, ceramics such as polycrystalline silicon carbide used as various structural members, semiconductors, etc. There are semiconductor materials such as single crystal silicon and / or single crystal silicon carbide to be a device wafer, and solar cell materials such as single crystal and polycrystalline silicon to be a solar cell wafer. The semiconductor material may be formed of a material mainly containing at least one of silicon and silicon carbide. In the example shown in FIG. 1, an example in which one wire electrode 2 is wound around a plurality of guide rollers 3 a to 3 d is shown. However, the present invention is not limited to this, and one wire electrode 2 is folded back. If a plurality of cutting wire portions 2a are formed by the above, the specific configuration is not particularly limited.

  In the present embodiment, the plurality of guide rollers 3a to 3d are arranged apart from each other in parallel in the axial direction. Guide rollers 3a and 3b are provided at a higher position, a guide roller 3c is provided at a lower position below the guide roller 3b, and a guide roller 3c is provided at a lower position below the guide roller 3a. Guide rollers 3d are provided so as to be lined up.

  The wire electrode 2 is wound around the guide rollers 3 a to 3 d a predetermined number of times, then discharged from a wire discharge roller (not shown), and collected by the wire winding bobbin 5. A portion of the wire electrode 2 stretched between the guide roller 3c and the guide roller 3d can be opposed to the workpiece 8, and a part thereof is a cutting wire portion 2a for processing the workpiece 8. . As shown in FIG. 1, the workpiece 8 is disposed so as to face the cutting wire portion 2 a with a small gap, and an electric discharge machining process is performed.

  A voltage (machining voltage) for performing electric discharge machining is supplied to the wire electrode 2 from the machining power source 6 via the power supply 7 </ b> A and 7 </ b> B, and a voltage is applied between the wire electrode 2 and the workpiece 8. The machining power supply 6 includes a plurality of machining power supply units 61 that can apply voltages independently of each other. The power supplies 7A and 7B are also composed of a plurality of power supply units that are insulated from each other, and are configured such that a voltage can be applied independently to each cutting wire portion 2a. As described above, the plurality of machining power supply units 61 capable of independently applying a voltage to the parallel wire electrodes are connected to a control device (not shown) of the wire electric discharge machining apparatus.

  Of course, the voltage application polarity can be appropriately reversed as necessary, as in general wire electric discharge machining. Since the position of the workpiece 8 is controlled by a position control device (not shown) so as to separate a minute gap from the wire electrode 2 wound between the guide rollers 3c and 3d, an appropriate discharge gap length is maintained. Has been. Although not shown, the machining fluid is supplied between the workpiece 8 and the wire electrode 2 by spraying or dipping, as in normal wire electric discharge machining.

  FIG. 2 is a front view of the nozzle 80 as viewed from the ejection port 82 side. The nozzle 80 ejects the machining liquid from the ejection port 82 and supplies the machining liquid between the workpiece 8 and the wire electrode 2. The nozzle 80 is formed with a through hole 96 through which the cutting wire portion 2a passes. The nozzles 80 are arranged on both sides of the workpiece 8 with the ejection ports 82 facing the workpiece 8 in a state where the cutting wire portion 2 a is passed through the through-hole 96.

  FIG. 3 is a plan sectional view of the nozzle 80 as seen from the direction perpendicular to the plane formed by the cutting wire portion 2a. Further, FIG. 4 is a front sectional view of the nozzle portion showing a section parallel to the cut surface in the process of cutting the workpiece.

  As shown in FIGS. 3 and 4, the nozzle 80 includes a main body 84, a jet outlet constituting plate 91, and an escape outlet constituting plate 92. A pipe connection hole 81 for supplying a machining fluid is formed in the main body 84. The pipe connection hole 81 is formed so as to penetrate the main body 84, and one side thereof is closed by the plug 85 shown in FIG. 2. A supply pipe 93 shown in FIG. 2 for supplying the machining liquid is connected to the other side of the pipe connection hole 81 formed through the main body 84. Note that the side closed by the plug 85 and the side connecting the supply pipe 93 may be reversed.

  The main body 84 is provided with a jet outlet constituting plate 91 and an escape outlet constituting plate 92 on the direction side in which the machining liquid is ejected and on the opposite direction side, respectively. In the main body 84, a wire passage hole 94 through which the cutting wire portion 2a passes is formed by a hole formed by the jet outlet constituting plate 91 and the escape outlet constituting plate 92. The wire passage hole 94 and the pipe connection hole 81 intersect inside the main body 84. Therefore, the machining fluid supplied from the supply pipe 93 to the pipe connection hole 81 travels to both ends of the wire passage hole 94.

  Thus, by attaching the jet outlet constituting plate 91 and the escape outlet constituting plate 92 to the main body 84, the through hole 96 having the jet outlet 82 as an opening on one end side becomes the jet outlet 82, the wire passing hole 94, and the escape hole. Consists of a mouth 83. As shown in FIG. 4, the opening area of the ejection port 82 and the escape port 83 is smaller than the opening area of the end portion of the wire passage hole 94. Further, the opening area of the escape port 83 is smaller than the opening area of the jet port 82.

  The jet port 82 is for supplying the machining fluid between the electrodes, and the escape port 83 is for passing the cutting wire portion 2 a into the nozzle 80. In the portion where the wire passage hole 94 and the pipe connection hole 81 intersect, a slight space is formed in the main body 84. The machining fluid that has flowed into the main body 84 from the pipe connection hole 81 is stored in this space, and the flow direction is changed by 90 degrees and ejected from the ejection port 82.

  The nozzle 80 is arranged so that the jet port 82 is close to both sides of the workpiece 8. The gap between the jet port 82 of the nozzle 80 installed on both sides of the workpiece 8 and the end face of the workpiece 8 is set to 0.1 mm to 0.3 mm when close processing is possible. Further, depending on the type of member of the workpiece 8 and the required slice thickness, the nozzle 80 is arranged so that the jet port 82 is separated from the workpiece 8 by about 50 mm in order to reduce damage due to the jet pressure of the machining liquid. In some cases. In order to efficiently discharge the processing waste, the distance between the ejection port 82 and the workpiece 8 is desirably 50 mm or less.

  The wire electrode 2 having a plurality of cutting wire portions 2 a is inserted into the nozzle 80 from the escape port 83 of one of the two nozzles 80, and goes out of the nozzle 80 from the ejection port 82. Then, the nozzle 80 is inserted into the nozzle 80 from the jet nozzle 82 of the other nozzle 80 facing the tip, and exits from the escape port 83 through the inside of the nozzle 80. Then, it contacts the power supply 7A or 7B and is wound around the guide rollers 3a to 3d. By repeating this, the wire electrode 2 can have a plurality of cutting wire portions 2 a arranged in parallel between the nozzles 80.

  The machining fluid guide unit 100 shown in cross-sectional views in FIGS. 3 and 4 will be described in detail. FIG. 5 is an enlarged view showing a schematic shape of the machining fluid guide 100. The machining fluid guide unit 100 is installed on the workpiece 8, and FIG. 5 shows a state before the electric discharge machining by the cutting wire unit 2a is started. Note that the nozzle 80 is not shown in FIG.

  FIG. 6 is a three-view diagram of the machining liquid guiding unit 100 including a top view, a side view seen in the wire traveling direction, and a side view seen from the other side. The machining fluid guide portion 100 is formed with the same number or more of linear slits 101 as the parallel wires constituting the cutting wire portion 2a.

  The length x in the processing direction (depth direction) of the slit 101 shown in the side view seen in the wire traveling direction in FIG. 6 is the length in the processing direction (depth direction) of the nozzle 82 of the nozzle 80 (see FIG. 6). 4 or more of y). Moreover, the pitch of the slit 101 is equal to the pitch of the parallel wires constituting the cutting wire portion 2a, and the groove width of the slit 101 is equal to or larger than the diameter of each wire constituting the cutting wire portion 2a. The length in the depth direction of the slit 101 is equal to the thickness of the workpiece 8 in the wire traveling direction, and the number of slits 101 is equal to or greater than the number of wires in the cutting wire portion 2a.

  Here, the position of the nozzle 80 with respect to the workpiece 8 is relatively moved by the movement of the stage 97 as the electric discharge machining proceeds, and the length of the cutting groove formed in the workpiece 8 is the outlet of the nozzle 80. When the dimension in the height direction of 82 is ½, the jet outlet 82 of the nozzle 80 is completely covered with the workpiece 8, so the length in the depth direction of the slit 101 is 1 / length of the jet outlet 82. 2 or more.

  Further, as shown in FIG. 6, the center portion on the upper surface side of the processing liquid guide portion 100, that is, the center portion on the opposite side to the surface on which the slit 101 is processed so as to accommodate the cutting wire portion 2a is the slit. A machining fluid discharge path 102 which is a through hole cut out toward 101 is formed. The machining fluid discharge path 102 reaches all the tips of the slits 101. That is, all the slits 101 and the machining liquid discharge path 102 are connected. The opening width of the machining fluid discharge path 102 in the wire traveling direction, that is, the length in the depth direction is shorter than the width of the machining fluid guide unit 100 in the wire traveling direction, and the slit 101 of the machining fluid guide unit 100 is processed on the surface. Thus, a frame having a thickness of several mm to several tens of mm is formed on the opposite surface.

  The machining fluid guide unit 100 is disposed at a portion where the thin plate is cut out in the workpiece 8 installed so that the portion cut into the plurality of thin plates faces the cutting wire portion 2a. The machining fluid guide 100 is installed and fixed on the upper surface of the workpiece 8 such that the surface in which the slit 101 is machined in the depth direction faces the machining start surface of the workpiece 8. At this time, the parallel wires constituting the cutting wire portion 2a are installed in the respective slits 101 of the machining liquid guide portion 100 in a state where the parallel wires are fitted one by one.

  The thickness of the workpiece 8 in the wire traveling direction is equal to the length of the slit 101 of the machining fluid guide 100 in the wire traveling direction, that is, the length of the machining fluid guide 100 in the wire traveling direction is equal. In FIG. 8, the processing liquid guide part 100 is arranged so that the surface on the side facing the nozzle 80 and the surface on the side facing the nozzle 80 in the processing liquid guide part 100 are in the same plane. Further, the machining liquid guide unit 100 is arranged with fine adjustment so that each parallel wire fitted in the slit 101 of the machining liquid guide unit 100 does not contact the inner surface of the slit 101. The processing liquid guide unit 100 is, for example, a workpiece by clamping the workpiece 8 and the processing liquid guide unit 100 using an adhesive, an adhesive sheet, screw fastening to the workpiece 8, or a vise. 8 is fixed.

  A non-conductive substance is used for the machining fluid guide unit 100 so as not to be subjected to electric discharge machining on the inner surface of the slit 101 or to prevent a short circuit between the wires when the cutting wire unit 2a comes into contact with each other. The Since the cutting wire portion 2a is running, the non-conductive material described above wears due to friction when contacted, so the inner surface of the slit 101 is made of a non-conductive material such as hard alumite or diamond-like carbon (DLC). It may be coated. Alternatively, the machining fluid guide 100 itself may be made of a nonconductive material such as a resin or a nonconductive ceramic.

  When the machining liquid is supplied to the nozzle 80 in the apparatus configuration and the arrangement state as described above, the machining liquid flows into the nozzle 80 through the supply pipe 93. The machining fluid that has flowed into the nozzle 80 is ejected from the ejection port 82 and discharged from the escape port 83. Here, it is desirable that the machining liquid flowing into the nozzle 80 is ejected only from the ejection port 82 and supplied to the gap between the workpieces 8, but the escape port 83 formed for passing the wire electrode 2. Are also discharged. However, as described above, since the opening area of the escape port 83 is smaller than the opening area of the jet port 82, most of the machining fluid is ejected from the jet port 82 having a smaller flow resistance. Yes. The width dimension of the ejection port 82 and the escape port 83 is formed so that the whole of the plurality of cutting wire portions 2a arranged in parallel can be accommodated.

  The machining liquid supplied to the two nozzles 80 arranged on both sides of the workpiece 8 is ejected from the ejection port 82 along the cutting wire portions 2a substantially on the same axis as the cutting wire portion 2a. To be sprayed. At this time, the machining liquid guide unit 100 is installed on the upper part of the machining start surface of the workpiece 8, and the ejection port 82 of the nozzle 80 is blocked by the machining liquid guide unit 100. Accordingly, even when the end surface of the workpiece 8 is processed, the processing liquid is not affected by the relative position between the jet port 82 and the end surface position of the workpiece 8, and the processing liquid is not limited to each slit of the processing liquid guide 100. A flow path that is rectified at 101, passes through the slit 101, passes through the machining liquid discharge path 102, and flows to the outside is secured. Thereby, the disturbance of the machining fluid flow is suppressed, and the vibration of the parallel wires constituting the cutting wire portion 2a is suppressed.

  In the initial stage of processing, since the depth of the cutting groove formed in the workpiece 8 is short, this corresponds to a state in which some slits are already formed by the slits 101 of the processing liquid guide part 100. With the machining liquid supplied to each slit 101 of the machining liquid guide unit 100, machining waste generated by electric discharge machining is discharged from the machining liquid discharge path 102 without staying between the electrodes.

  When a voltage is applied between the wire electrode 2 and the workpiece 8 while the wire electrode 2 is running in this state to raise the stage 97, the workpiece 8 fixed to the stage 97 rises. When the wire electrode 2 and the workpiece 8 gradually approach each other and become a gap of about several tens to several hundreds of microns, the workpiece 8 is melted by the electric discharge generated between the wire electrode 2 and removed. Machining such as machining feed rate, discharge frequency, machining current, applied voltage, machining fluid flow rate, machining fluid pressure, wire travel speed, etc. so as to maintain the gap, that is, the distance between the electrodes, so that such a discharge state continues. By controlling the conditions while changing the conditions, the workpiece 8 is gradually deeply processed with cutting grooves corresponding to the parallel wires, that is, grooves for cutting the workpiece 8 into a plurality of thin plates.

  According to such a configuration, even when the end surface of the workpiece 8 is processed, the disturbance of the machining fluid flow is suppressed, and the vibration of the cutting wire portion 2a is also suppressed. Is less likely to occur, and a large machining energy can be set, so that the machining speed can be increased. In addition, the decrease in the discharge frequency due to wire vibration is improved, and the processing speed is improved. Further, even if the cutting fluid depth and the hydraulic pressure cannot be increased because the cutting groove depth in the workpiece 8 is insufficient, this is equivalent to a state where the cutting groove is formed sufficiently deep, and the hydraulic pressure and flow rate are reduced. By increasing the height, the machining liquid can be pressed into the slit 101, and the machining waste can be discharged from between the gaps, so that the machining speed can be improved.

  The above-described machining fluid guiding unit 100 is effective in speeding up and stabilizing the wire electric discharge machining at the start of machining, that is, in the vicinity of the end surface of the workpiece 8. Even if the processing progresses and the cutting groove becomes deep, the relative positional relationship between the nozzle 82 of the nozzle 80 and the cutting groove does not change, and the processing liquid supply state by the processing liquid guide 100 does not change. The supply state of the machining fluid from the beginning to the end of cutting of the workpiece 8 is stabilized. Therefore, there is no need to change the processing conditions, and processing can be performed under constant processing conditions from the start of processing to the end of processing, so the processing time can be shortened, and the cutting groove that affects the thickness variation of the cut thin plate can be reduced. The width can be narrowed and processed uniformly, improving the processing accuracy.

  Further, by the wire electric discharge machining method using the wire electric discharge machining apparatus described above, a semiconductor material such as crystalline silicon and / or single crystal silicon carbide, a solar cell material such as single crystal or polycrystalline silicon, or polycrystalline silicon carbide. It is possible to process sputtering target materials such as ceramics, tungsten and molybdenum. When such a material is processed as the workpiece 8, the electromagnetic force acting between the wires during electric discharge machining is offset or reduced, and the wire electrode 2 is prevented from being bent. It can be cut out with high dimensional accuracy.

Embodiment 2. FIG.
FIG. 7 is a three-view diagram including a top view of the machining fluid guide 130 provided in the wire electric discharge machining apparatus according to Embodiment 2, a side view seen in the wire travel direction, and a side view seen from the other side. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In the second embodiment, the structure of the machining liquid guide unit 130 is simplified in order to simplify the production of a slit portion that separates and passes the wire electrodes 2 (the plurality of cutting wire portions 2a) before starting the machining. Has changed.

  When it is going to produce the processing liquid guide part 100 demonstrated in Embodiment 1, for example, the outline of the slit 101 is cut out from a bulk-shaped member by wire electric discharge machining, and is further processed by cutting using an end mill or the like. A liquid discharge path 102 is formed. Although the machining liquid guide part 100 can be manufactured by this method, since it is an integrally molded product, the dimension adjustment when the specification change occurs in the slit 101 is not effective, and the entire machining liquid guide part 100 needs to be newly recreated. There is.

  Therefore, in the second embodiment, the slit 101 and the machining liquid discharge passage 102 are not formed by cutting out from the bulk-shaped member as described above, but are different in thickness and length as shown in FIG. A structure is formed by alternately laminating various types of thin plates.

  The structure of the slit 101 of the machining fluid guide 130 will be described in detail. The slit 101 is formed by alternately stacking a partition plate 103 for separating each slit 101 and a side plate 104 for forming a slit side surface so that there is no gap. Further, fixing blocks 105 are provided on both sides of the partition plate 103 that are stacked in the same number or more as the number of the parallel wires constituting the cutting wire portion 2a and not in contact with the side plate 104. Each partition plate 103, each side plate 104, and the two fixing blocks 105 are processed with through holes for passing fastening bolts 106, and are inserted from the through holes of one fixing block 105. The bolt 106 passes through the through hole of the fixing block 105 located on the opposite side and is fastened with the nut 107. In this way, the slit 101 is configured by screwing the plates in the stacked state. It should be noted that the fastening bolt 106 has an insulating coating treatment such as a hard anodizing treatment so that the side plates 104 and the fixing block 105 are not electrically connected by contacting the side plates 104 and the fixing block 105 at the time of fastening. Or made of an insulating material such as resin or insulating ceramics.

  The shape of the slit 101 is adjusted by the shape of the partition plate 103 and the side plate 104. That is, the upper side and the front side of the partition plate 103 and the side plate 104 constitute a surface that faces the upper surface of the machining liquid guide portion 130 and the nozzle 80, so that the upper side and the front side of the partition plate 103 and the side plate 104 are aligned. After aligning to, tighten. Therefore, the length of the slit 101 of the machining liquid guide 130 can be set by adjusting the length dimension of the slit 101 of the partition plate 103 and the side plate 104 in the machining direction (the moving direction of the stage 97). At this time, the partition plate 103 is shorter in the processing direction than the side plate 104 and is made of a non-conductive material. It is further preferable that the side plate 104 and the fixing block 105 are also made of a non-conductive material. Further, the width of the slit 101 (the width in the extending direction of the bolt 106 in FIG. 7) can be set by the thickness of the partition plate 103, and the interval between the slits 101 is the thickness between the partition plate 103 and the side plate 104, that is, the partition. The thickness can be set by laminating the plate 103 and the side plate 104 one by one.

  The configuration of the machining fluid discharge path 102 will be described. The dimension of the partition plate 103 and the side plate 104 in the wire traveling direction is set shorter than ½ of the dimension of the fixing block 105 in the wire traveling direction. If two partitions 101 and side plates 104 are overlapped to form slits 101 are prepared, and the slits 101 are aligned and fastened with reference to the nozzle-facing surface side of the fixing block 105, they are fixed. Since the dimension of the laminated slits 101 in the wire traveling direction is shorter than that of the block 105 for use, the two laminated slits 101 are not in contact with each other, and a gap is formed in the central portion of the fixing block 105. A machining fluid discharge path 102 is formed. Since the machining liquid discharge path 102 is formed by the gap between the two stacked slits 101 as described above, the dimension of the machining liquid discharge path 102 is determined by the wire travel between the partition plate 103 and the side plate 104 constituting the slit 101. It can be set by the direction dimension.

  By configuring the machining fluid guide 130 by the above-described method, the manufacturing time of the machining fluid guide 130 can be significantly shortened. In particular, since the shape processing of the slit 101 that requires processing time is simple plate processing and hole processing, it is possible to easily cope with changes in the specifications of the slit 101 and the machining fluid discharge path 102. Further, since a resin material that cannot be processed by wire electric discharge machining can be processed, it becomes easy to replace a portion that requires electrical insulation with a non-conductive component. Furthermore, because of the laminating and assembling type of plate parts, it is possible to flexibly cope with changes in the number of slits and damage to specific slits by adding / removing or replacing the partition plate 103 and the side plate 104.

  FIG. 8 is a modification of the slit 101 portion in the machining liquid guide 130 shown in FIG. In FIG. 7, the machining liquid discharge path 102 is configured by using two slits 101 in which the partition plates 103 and the side plates 104 are alternately overlapped. In FIG. 8, the dimension of the side plate 104 in the wire traveling direction is the same as that of the fixing block 105, and the dimension in the wire traveling direction of only the partition plate 103 is shortened to alternately stack the side plate 104 with the machining fluid discharge path 102. I am trying to configure it. The area of the machining liquid discharge path 102 is reduced as compared with the method of FIG. 7, but by reducing the length of the partition plate 103 in the wire traveling direction, the area of the machining liquid discharge path 102 can be adjusted. Depending on the electrical discharge machining, the generated machining waste is discharged to the outside without staying at the machining fluid guide unit 130. In addition, although the structure which shortened the length of the wire traveling direction of the partition plate 103 from the side plate 104 was described here, the length of the side plate 104 in the wire traveling direction was made shorter than the partition plate 103 and divided into the front and rear groups. The same effect can be obtained even if the machining fluid discharge path 102 is formed by a break between the side plates 104.

  Further, by the wire electric discharge machining method using the wire electric discharge machining apparatus described above, a semiconductor material such as crystalline silicon and / or single crystal silicon carbide, a solar cell material such as single crystal or polycrystalline silicon, or polycrystalline silicon carbide. It is possible to process sputtering target materials such as ceramics, tungsten and molybdenum. When such a material is processed as the workpiece 8, the processing speed is increased and the cutting groove width can be reduced, so that more members can be obtained from one ingot, and a plurality of members can be obtained at a time. Can be cut out with high dimensional accuracy.

Embodiment 3 FIG.
FIG. 9 is a partially enlarged perspective view of the machining fluid guide 140 provided in the wire electric discharge machining apparatus according to the third embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In the third embodiment, in order to further facilitate the operation of passing the wire electrode 2 (the plurality of cutting wire portions 2a) to the machining liquid guide section 140, the production of the machining liquid guide section 140 itself is further simplified. In doing so, the configuration of the machining fluid guide 140 is changed.

  In the third embodiment, the cutting wire is provided in one wide slit 150 without providing a plurality of slits 101 for individually passing each wire constituting the cutting wire portion 2a in the machining liquid guide portion 140. It is structured to allow the parts to pass together. As shown in FIG. 9, when the machining liquid guide part 140 is installed on the machining side upper surface of the workpiece 8, the shape of the slit 150 of the machining liquid guide part 140 is such that the width of the parallel wires constituting the cutting wire part 2a is as follows. All have a rectangular shape with a width of about 1 mm wider than the parallel width and a height of about 1 mm to several mm, and the slit 150 is in the depth direction of the machining liquid guide 140 (cutting thickness direction of the workpiece 8). Further, the slit 150 is processed so that the cross-sectional shape thereof is the rectangular shape. Further, similarly to the machining fluid guide 100 of the first embodiment, the machining fluid discharge path 102 is penetrated from the surface opposite to the slit machining surface of the machining fluid guide 140 to the slit 150.

  As described above, the machining liquid guide part 140 has a simple shape without the slits 101 for fitting the parallel wires constituting the cutting wire part 2a one by one. Even in the installation work of the workpiece 8 on the upper surface on the processing side, it is possible to save the trouble of fine adjustment so that the inner surface of the processing liquid guide portion 140 does not contact the cutting wire portion 2a. Further, when the flow rate or pressure of the machining fluid flowing into the slit 150 of the machining fluid guide 140 is insufficient, the slit adjusting plate 131 is sandwiched between the machining fluid guide 140 and the workpiece 8. The height of the slit 150 can be adjusted.

  FIG. 10 is a modified example of the machining fluid guide unit 140. If there is no change in the number of thin plates cut out from the workpiece 8, that is, the number of parallel wires constituting the cutting wire portion 2a, the machining fluid guide portion 140 needs to greatly change the slit shape as shown in FIG. There is no. However, when the number of thin plates cut out from the workpiece 8 is small, the number of parallel wires constituting the cutting wire portion 2a is reduced for processing. At this time, when the area of the slit 150 of the machining liquid guide 140 is larger than necessary with respect to the cutting groove formed by electric discharge machining, the machining liquid ejected from the nozzle 80 flows out toward the slit 150, that is, Since it becomes difficult to press-fit into a cut groove having a narrow groove width, the effect of discharging the machining waste from the gap decreases.

  Therefore, the machining liquid guide part 140 is configured to have a slit 150 through which the cutting wire part 2a passes between the slit adjusting plates 132 serving as the legs on both sides as shown in FIG. By adopting such a configuration, the slit 150 can be easily adjusted not only to the height but also to the width corresponding to the number of wires by adjusting the thickness, width, and number of the slit adjusting plates 132. it can. Further, when the cutting wire portion 2a is relatively translated in order to change the cutting position of the workpiece 8, if the slit adjusting plate 132 having a different width is used, the position of the slit 150 of the processing liquid guide portion 140 is used. The cutting wire portion 2a can be passed through the central portion of the slit 150 of the machining fluid guide portion 140. When the number of parallel wires of the cutting wire portion 2a is increased, the width of the slit 150 can be easily increased by reducing the width of the slit adjusting plate 132.

  Further, by the wire electric discharge machining method using the wire electric discharge machining apparatus described above, a semiconductor material such as crystalline silicon and / or single crystal silicon carbide, a solar cell material such as single crystal or polycrystalline silicon, or polycrystalline silicon carbide. It is possible to process sputtering target materials such as ceramics, tungsten and molybdenum. When such a material is processed as the workpiece 8, the processing speed is increased and the cutting groove width can be reduced, so that more members can be obtained from one ingot, and a plurality of members can be obtained at a time. Can be cut out with high dimensional accuracy.

  Furthermore, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent requirements.

  For example, even if some constituent elements are deleted from all the constituent elements shown in each of the first to third embodiments, the problem described in the column of the problem to be solved by the invention can be solved, and the column of the effect of the invention. When the effects described in (1) are obtained, a configuration in which this configuration requirement is deleted can be extracted as an invention. Furthermore, the structural requirements over the first to third embodiments may be combined as appropriate.

  As described above, the wire electric discharge machining apparatus according to the present invention is useful for manufacturing a thin plate, and is particularly suitable for manufacturing a semiconductor material and a solar cell material that require high dimensional accuracy.

DESCRIPTION OF SYMBOLS 1 Wire bobbin 2 Wire electrode 2a Cutting wire part 3a, 3b, 3c, 3d Guide roller 5 Wire winding bobbin 6 Power supply for processing 7A, 7B Electric power supply 8 Workpiece 14a, 14b Wire guide roller 15a, 15b Wire presser 61 Processing power supply Unit 80 Nozzle 81 Pipe connection hole 82 Jet outlet 83 Escape port 84 Main body 91 Ejection outlet configuration plate 92 Escape port configuration plate 93 Supply piping 94 Wire passage hole 96 Through hole 97 Stages 100, 130, 140 Work fluid guides 101, 150 Slit 102 Processing fluid discharge path 103 Partition plate 104 Side plate 105 Fixing block 106 Bolt 107 Nut 131, 132 Slit adjusting plate

Claims (13)

A wire electrode having a plurality of cutting wire portions facing the workpiece while being spaced apart from each other in parallel;
A machining power source for generating a pulsed machining voltage;
A plurality of electrons that are electrically connected to a plurality of the cutting wire portions and apply the machining voltage between the plurality of cutting wire portions and the workpiece to cause discharge;
An ejection port through which the machining liquid is ejected along the plurality of cutting wire portions toward the plurality of cutting grooves formed in the workpiece by the discharge and through which the plurality of cutting wire portions can pass is the workpiece. A nozzle formed to face
A machining fluid guide section provided in contact with the workpiece, having a plurality of slits each opening toward the workpiece and capable of accommodating a plurality of cutting wire sections one by one;
A wire electric discharge machining apparatus comprising: The wire electrical discharge machining apparatus according to claim 1, wherein a pitch of the slit is equal to a pitch of the cutting wire portions arranged in parallel, and a groove width of the slit is equal to or larger than a diameter of the wire electrode. The wire electric discharge machining apparatus according to claim 1, wherein a length of the slit in the machining direction is ½ or more of a length of the ejection port in the machining direction. The said slit is provided in the surface on the opposite side to the surface in which the said slit of the said process liquid guide part was formed, and is connected with the process liquid discharge path which discharges the said process liquid. Wire electrical discharge machining equipment. The wire electrical discharge machining apparatus according to claim 1, wherein the machining liquid guide portion or the inner surface of the slit is made of a non-conductive material. The non-conductive material is hard anodized or diamond-like carbon (DLC)
The wire electric discharge machining apparatus according to claim 5, wherein: The machining liquid guide unit alternately overlaps a side plate separating the slits and a partition plate having a groove width of the slit and having a length in the processing direction shorter than that of the side plate in the processing direction of the slit. The wire electric discharge machining apparatus according to claim 1, wherein the slit is formed. The working liquid discharge path for discharging the working liquid to the gap between the two is provided by separating two side plates and the partition plates alternately arranged in the wire traveling direction. The wire electrical discharge machining apparatus according to claim 7. The wire electric discharge machining apparatus according to claim 7 or 8, wherein the side plate and the partition plate are made of a non-conductive material. A wire electric discharge machining method, wherein the workpiece is sliced by the wire electric discharge machining apparatus according to any one of claims 1 to 9. A thin plate manufacturing method, wherein the workpiece is processed into a plurality of thin plates using the wire electric discharge machining apparatus according to any one of claims 1 to 9. A method for manufacturing a semiconductor wafer, comprising: processing a semiconductor material into a plurality of semiconductor wafers using the wire electrical discharge machining apparatus according to claim 1. The method for manufacturing a semiconductor wafer according to claim 12, wherein the semiconductor material is formed of a material mainly containing at least one of silicon and silicon carbide.

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