JP2014065116A - Work oscillation method and work oscillation device of wire saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work oscillation device in place of an oscillation shaft drive system to simplify an oscillation mechanism and to easily change modes of an oscillatory movement by leaving the oscillation mechanism mechanically unchanged in a wire saw.SOLUTION: In a wire saw 2 which performs a feed motion of a work 5 in a depth setting direction to a cutting area of a wire 4 under travel to cut the work 5, a support 6 which supports the work 5 is supported by the respective feed screws 7, 8 and feed nuts 9, 10 on one side and the other side of a travel direction of the wire 4, the respective feed screws 7, 8 are rotated by drive motors 11, 12, the feed motion in the depth setting direction or an extraction direction is given to the work 5, difference in feed ratio per unit time is given between one drive motor 11 and the other drive motor 12, and an oscillatory movement is given to the work 5.

Description

  The present invention relates to a technique for swinging a workpiece such as a semiconductor ingot with a wire saw.

  In a wire saw, when a workpiece is cut, the workpiece and the wire of the wire saw are relatively swung as disclosed in, for example, Patent Literature 1, Patent Literature 2, and Patent Literature 3.

  In the techniques of Patent Document 1, Patent Document 2 and Patent Document 3, in order to swing the workpiece, the support portion of the workpiece is supported by a swing shaft orthogonal to the wire, and the support portion of the workpiece is reciprocated. Alternatively, by swinging the swinging shaft, swinging motion in the traveling direction of the wire row is given to the support portion of the work around the swinging shaft to swing the work.

  According to the swing shaft drive system as described above, the swing mechanism of the wire saw becomes a large-scale device for a workpiece of a large semiconductor ingot having a diameter of about 450 mm, and the swing motion mode is the position of the swing shaft and the swing mechanism. It will be determined by the configuration. For this reason, it is difficult to set the most appropriate swinging motion, and the setting range of the wire saw cutting conditions is limited.

JP 61-182760 A JP-A-08-85053 JP 2011-167810 A

  Accordingly, an object of the present invention is to provide a workpiece rocking method and apparatus that replaces the rocking shaft drive system in a wire saw, simplifying the rocking mechanism, and without mechanically changing the rocking mechanism, It is to make it possible to easily change the mode of the swing motion.

  Based on the above problems, the present invention supports both ends of a support portion of a workpiece such as a semiconductor ingot so that it can be moved by a plurality of feed screws and feed nuts, and the feed screw at each end is rotated by a drive motor. When moving the workpiece, a swinging motion is given to the workpiece by adding a difference in feed amount per unit time to the feed screw at each end.

  More specifically, in the wire saw workpiece swinging method according to the present invention, the workpiece is fed and moved in the cutting direction with respect to the cutting region of the wire row that is running, and the workpiece is supported in the wire saw that cuts the workpiece. The support is supported by a feed screw and a feed nut on one side and the other side in the traveling direction of the wire, and each feed screw is rotated by a corresponding drive motor to cut or pull the workpiece. In addition, a swinging motion is given to the workpiece by giving a difference in feed amount per unit time according to a rotational speed command between one drive motor and the other drive motor ( Claim 1).

  The command for the rotational speed of one drive motor and the command for the rotational speed of the other drive motor are set by superposing wavy waveforms on a constant value to form a speed waveform and shifting the phases of the two speed waveforms (invoiced). Item 2), which is set by forming a velocity waveform from a mountain-shaped waveform followed by 0 to a low value and shifting the phase of the two velocity waveforms (Claim 3), and a mountain-shaped waveform having a larger feed direction. And a small mountain-shaped waveform in the return direction are repeated every predetermined time to form a velocity waveform, and the phase is set by shifting the phases of the two velocity waveforms.

  And the workpiece rocking device of the wire saw according to the present invention includes: a support body that supports the workpiece in a wire saw that feeds and moves the workpiece in a cutting direction with respect to a cutting area of the traveling wire row, and cuts the workpiece; A plurality of feed screws provided on one side and the other side in the traveling direction of the wire and arranged in parallel to the cutting direction of the workpiece, and connected to each end of the support, A feed nut that fits under a screw pair, a plurality of drive motors that rotate each of the feed screws, and a rotation motion of each of the drive motors to give a feed movement in the cutting direction or the drawing direction to the workpiece; A controller that imparts a swinging motion to the workpiece by providing a difference in feed amount per unit time between one drive motor and the other drive motor. It is constituted by (claim 5).

  In the wire saw work swinging apparatus, the present invention is also characterized in that a feed nut at each end of the support is connected to a holding shaft at each end perpendicular to the traveling direction of the wire, The other end of the support is connected to the holding shaft by a long groove bearing.

  According to the wire saw workpiece swinging method and the workpiece swinging device according to the present invention, the mechanical parts are assembled by the workpiece support plate, the feed screw, the feed nut and the drive motor. The mechanical structure of the oscillating device can be simplified without increasing its size, and by changing the rotational speed command for the drive motor, the feed movement in the workpiece cutting direction, the feed movement in the drawing direction of the workpiece, and the workpiece oscillation The mode of movement can be easily changed without changing the mechanical configuration. Further, since the wire intersects the cut surface and the surface is ground, the waviness and unevenness of the cut surface can be reduced (claims 1 and 5). ).

  According to the wire saw work swinging method according to the present invention, various swinging motions can be set according to the rotational speed command to the drive motor, so the workpiece material and physical properties, wire grinding characteristics, wire saw cutting conditions Accordingly, an appropriate swing motion can be selected (claims 2, 3 and 4).

  Furthermore, in the workpiece swinging device of the wire saw, since one of the support plates is supported by the bearing and the other is supported by the long groove bearing, it can cope with a change in the distance between the holding shafts accompanying the swinging motion of the support plate, Moreover, since one side is restrained by the bearing, unnecessary movement of the workpiece in the traveling direction of the wire is eliminated, so that the cutting process is stabilized (Claim 6).

It is a front view of the workpiece | work rocking | fluctuation apparatus of the wire saw which concerns on this invention. It is a top view of the work rocking | fluctuation apparatus of the wire saw which concerns on this invention. It is a front view of one support part of a support plate. It is a front view of the other support part of a support plate. It is explanatory drawing of rocking | fluctuation motion. It is a front view of the rocking | fluctuation state of the workpiece | work with respect to a wire. It is a wave form diagram of the rotational speed of a time-drive motor. It is explanatory drawing of the cut surface of a thin plate-shaped object.

  1 to 4 show a wire saw work rocking device 1 based on a wire saw work rocking method according to the present invention. A wire saw work swinging device 1 is premised on a wire saw 2.

  As shown in FIG. 1, the wire saw 2 is configured such that, for example, a wire 4 is spirally wound between two parallel processing rollers 3, and the wire 4 is reciprocated or continuously traveled by the rotation of the processing roller 3. The workpiece 5 such as a semiconductor ingot, for example, a silicon ingot, is pressed against the cutting region of the parallel wire row between the processing rollers 3 and is moved in the cutting direction, that is, the direction perpendicular to the plane of the wire row, The workpiece 5 is cut as a thin plate-like body such as a large number of wafers. The wire 4 is an abrasive fixed wire or a free abrasive wire.

  As shown in FIG. 1 and FIG. 2, the wire saw work swinging device 1 according to the present invention includes a support 6 that supports the work 5 and one side in the traveling direction of the wire 4, that is, the downstream side. And the other side, that is, the upstream side, are connected to a plurality of feed screws 7 and 8 arranged in parallel to the cutting direction of the work 5 and the respective ends of the support 6, and the feed screws 7 and 8. And feed nuts 9 and 10 fitted to the screw pair, drive motors 11 and 12 for rotating the feed screws 7 and 8, and a controller 13 for controlling the rotation of the drive motors 11 and 12, respectively. doing.

  The support 6 supports the workpiece 5 on its lower surface, for example. The work 5 is fixed to the fixing plate 15 by an adhesive 14, is attached to the lower surface of the support 6 via the work plate 16, and faces the cutting area of the wire 4.

  The plurality of feed screws 7 and 8 are preferably constituted by a total of four ball screw shafts for stable support of the workpiece 5, and two of the feed screws 7 are shown in FIGS. 2, the other two lead screws 8 are disposed at the right end of the support 6 in FIGS. 1 and 2. These feed screws 7, 8 are provided in a direction perpendicular to the plane of the wire row between the processing rollers 3, that is, parallel to the cutting direction of the workpiece 5, and upper and lower ends of the feed screws 7, 8. The portions are rotatably supported on the frame 24 of the wire saw 2 by thrust bearings 17 and 18, respectively.

  Each feed screw 7, 8 is connected to a corresponding drive motor 11, 12. Usually, one drive motor 11 is connected to one of the two feed screws 7, and transmits the rotational force to the other by a rotation transmission means (not shown) such as a timing belt and a pulley. Similarly, the drive motor 12 is connected to one of the two feed screws 8 and transmits the rotational force to the other by a rotation transmission means such as a timing belt / pulley.

  As described above, the feed nuts 9 and 10 that fit into the four feed screws 7 and 8 fit into the corresponding feed screws 7 and 8, respectively, under the screw pair. The two feed nuts 9 at the left end are connected to a holding shaft 19 orthogonal to the traveling direction of the wire 4, and the two feed nuts 10 at the right end are held orthogonal to the traveling direction of the wire 4. It is connected to the shaft 20.

  Further, as shown in FIGS. 2 and 3, the left end portion of the support 6 is rotatably connected to the left holding shaft 19 by two bearings 21 attached to the support 6. As shown in FIGS. 2 and 4, the right end of the support 6 is rotatable with respect to the right holding shaft 20 by two long groove bearings 22 attached to the support 6, and the direction of the long groove 22a. It is connected as a state that allows the movement of. The long groove 22a of the long groove bearing 22 is formed in the traveling direction of the wire 4 and is open at one end, but may be a closed long hole.

  The controller 13 is constituted by a part of a control device (not shown) of the wire saw 2 or a dedicated control unit such as a computer. The controller 13 rotates the drive motors 11 and 12 to feed in the cutting direction when the workpiece 5 is cut. While giving a motion, the feed amount per unit time is differentiated between the drive motor 11 on one side of the support 6 and the drive motor 12 on the other side of the support 6. A swinging motion is given to the workpiece 5 and, if necessary, a swinging motion is also given to the workpiece 5 when a large number of plate-like bodies are extracted from the wire row of the wires 4 after the workpiece 5 is cut.

  In preparation for the cutting operation by the wire saw 2, the operator operates the input device 23 of the controller 13, designates the drive motors 11 and 12 separately, and feeds and extracts per unit time for cutting on the time axis. The rotational speed data corresponding to the feed amount per unit time is input to the controller 13, and the controller 13 stores the rotational speed data for each of the drive motors 11 and 12.

  The feed amount per unit time for cutting and extraction is set by the rotational speeds of the drive motors 11 and 12. Further, the swinging motion during the feed movement of the workpiece 5 is a difference in feed amount per unit time between the two drive motors 11 and 12, that is, a rotational speed command, for example, a rotational speed command of the same two waveforms. Is set as command data in which the phase of is shifted.

  At the time of cutting the workpiece 5, the controller 13 rotates the drive motor 11 according to, for example, a command of the rotational speed of the waveform of one drive motor 11 in order to give the feed motion and feed motion in the cutting direction, and at the same time the other drive With respect to the motor 12, the drive motor 12 is rotated in accordance with a rotational speed command having a waveform out of phase with respect to the waveform of the drive motor 11 described above. The phase of the rotational speed command is shifted between the drive motors 11 and 12, and the rotational speeds of the drive motors 11 and 12 are different at the same time point. As a result, the feed amount per unit time is different. The nut 9 and the feed nut 10 on the right side advance in the cutting direction while being alternately advanced based on the difference in feed amount per unit time in the course of the feed movement in the cutting direction.

  FIG. 5 illustrates the movement in the cutting direction by the swinging motion of the support plate 6 and the workpiece 5. In the process of moving in the cutting direction, the support plate 6 moves in the cutting direction of the arrow while alternately turning the left and right ends and repeating the inversion of the inclined direction when viewed from the front. As a result, the workpiece 5 integrated with the support plate 6 moves in the direction of the arrow as shown in FIG. 6 while repeating the swinging motion.

  During this oscillating movement, the distance between the left and right support portions of the support plate 6, that is, the holding shafts 19 and 20, changes, but the long groove bearing 22 allows the movement of the holding shaft 20 inside the long groove 22a. Allow distance change during rocking motion. The swing angle of the workpiece 5 with respect to the wire 4 can be arbitrarily set within a possible range, but is usually set within a range of about ± 5 to 30 degrees due to design restrictions and the like.

  When cutting, a resistance force in the direction opposite to the cutting direction is applied to the work 5, and the resistance force is a contact slope between the screw portions of the feed screws 7 and 8 and the feed nuts 9 and 10, that is, the male screw and the female screw. Therefore, the work 5 does not move in the direction opposite to the cutting direction due to the resistance.

  FIG. 7 shows the relationship of time T-rotational speed V for the drive motors 11 and 12. (1) in FIG. 7 forms a velocity waveform by superposing wavy waveforms on a constant value, and the rotational speed V11 of the drive motor 11 and the rotational speed V12 of the drive motor 12 are shifted by shifting the phase of the two velocity waveforms. In this mode, rotational speed commands are set, and the left and right drive motors 11 and 12 are continuously rotated in the feed direction by these rotational speed commands, and the rotational speeds are alternately increased or decreased. Here, the continuous rotation in the feeding direction corresponds to the above-mentioned constant value speed, and the increase / decrease in the rotational speed corresponds to the above-mentioned wavy waveform.

  In FIG. 7 (2), a speed waveform is composed of a high chevron waveform followed by 0 (stop) to a low value, and the rotational speed V11 of the drive motor 11 is shifted by shifting the phase of the two speed waveforms. A rotation speed command of the rotation speed V12 of the drive motor 12 is set, and the drive of the other drive is performed while temporarily rotating one drive motor 11 or rotating at a low speed in the feed direction according to these rotation speed commands. In this mode, the motor 12 is rotated in the feed direction, and these rotation states are alternately repeated. Here, the temporary stop and the low-speed rotation correspond to 0 to a low value, and the increase / decrease in the rotation speed corresponds to a mountain-shaped waveform.

  FIG. 7 (3) shows a velocity waveform formed by repeating a large chevron waveform in the feed direction and a small chevron waveform in the return direction at predetermined time intervals, and the phases of the two velocity waveforms are shifted by a predetermined phase. Thus, the rotational speed command of the drive motor 11 and the rotational speed V12 of the drive motor 12 are set, the left and right drive motors 11 and 12 are rotated by these rotational speed commands, and the left and right feed nuts 9 are rotated. 10 is reciprocating movement, in other words, moving in the feeding direction while alternately repeating the movement in the feeding direction (+) and the movement in the return direction (−) smaller than this. Here, the movement in the feed direction corresponds to a large mountain-shaped waveform, and the movement in the return direction, that is, the direction opposite to the feed direction, corresponds to a small mountain-shaped waveform.

  As described above, the rotation speed command of the controller 13 is obtained by combining the rotation direction and the stop time with the rotation speed V11 and V12 waveforms of the drive motors 11 and 12, shifting their phases, and shifting the drive motor 11 and the other drive motor 11 and the other. A difference is made in the feed amount per unit time between the drive motor 12 and the workpiece 5 is given a swinging motion. The mode of these swinging motions is selected according to the cutting conditions of the wire saw 2, the grinding function of the wire 4, the physical properties of the workpiece 5, and the like.

  In the process of moving the workpiece 5 in the cutting direction while repeating the swinging motion, the wire 4 starts to cut the workpiece 5 and finally cuts to the middle position of the thickness of the fixed plate 15 to cut the workpiece 5. Finish. In this way, the workpiece 5 is cut thinly into a large number of thin plates such as wafers. Many plate-like bodies are held by the work plate 16 together with the fixed plate 15 at this time. At the time of cutting, a coolant is used as necessary.

  In the cylindrical work 5, the cut is short at the beginning and the end of cutting, and the cut is long at the intermediate period. For this reason, the feed speed in the cutting direction of the work 5 is made inversely proportional to the cut length under the modes (1) to (4) in FIG. It can also be set low.

  After this cutting, a large number of thin plate-like bodies such as wafers are pulled out of the wire 4 by the movement of the support 6 in the return direction. Even in this pulling process, the controller 13 is necessary as described above. Accordingly, the rotational speeds V11 and V12 of the drive motors 11 and 12 are controlled, and a swinging motion is given to the support 6 and a large number of plates after cutting.

  FIG. 8 illustrates the occurrence of cut marks on the plate-like body surface 5a. The cutting traces appear on the plate-like body surface 5a as waviness and unevenness overlapping the waviness, and these are formed as streak shapes that are substantially parallel to the traveling direction of the wire 4 at the time of cutting. At the time of cutting the workpiece 5 and at the time of pulling out the plate-like body after cutting, the swinging movement of the workpiece 5 causes the wire 4 to intersect the streaky undulations and streaky irregularities of the plate-like body surface 5a. At this time, the convex apex portion 5b is ground to the position of the broken line, for example, by the grinding action of the wire 4, so that the plate-like body surface 5a becomes a smooth surface and is finished within the standard range of the product.

  In this way, the swinging motion acts to suppress waviness appearing on the cut surface when the workpiece 5 is cut, that is, the plate-like body surface 5a, and to reduce fine irregularities overlapping the waviness. Even in the process in which a large number of plate-like bodies are pulled out from the wire 4 after the cutting, if the rocking motion is given to the many plate-like bodies, the undulations on the surface of the plate-like body 5a are suppressed, and the fine irregularities overlapping the undulations. Are further suppressed and reduced.

  In the illustrated example, since the wire 4 is disposed below the workpiece 5, the feeding direction of the workpiece 5 is downward. However, when the wire 4 is disposed above the workpiece 5, the workpiece 5 is fed. The direction is set as upward. In the illustrated example, the support 6 is supported by a total of four feed screws 7 and 8 and feed nuts 9 and 10 and guided in the feed direction. If the support 6 is stable, the support 6 can be supported and guided by a total of two feed screws 7, 8 and feed nuts 9, 10.

  According to the wire saw work rocking device 1 as described above, unlike the rocking shaft drive system, the work plate 5 is mechanically driven by the support plate 6, feed screws 7 and 8, feed nuts 9 and 10, and drive motors 11 and 12. Since the part is assembled as a gate shape and an installation space for the workpiece 5 is formed inside the gate shape, even if the workpiece 5 becomes large, no special change is required for the mechanical configuration, and the size increases. Furthermore, when the feed motion in the cutting direction is given to the workpiece 5 or the feed motion in the pulling direction is given to the workpiece 5 by changing the rotational speed command to the drive motors 11 and 12, the swing motion of the workpiece 5 is changed. The mode can be easily changed by an input command to the controller 13 without changing the mechanical configuration.

  Further, since one of the support plates 6 is supported by the bearing 21 and the other is supported by the long groove bearing 22, the distance between the left and right support points, that is, the holding shafts 19 and 20, accompanying the swinging motion of the support plate 6 is changed. Correspondingly, the cutting process of the workpiece 5 is stabilized.

  Although the present invention was developed mainly for the purpose of manufacturing a silicon inwafer from a silicon ingot, the present invention can also be used for cutting other semiconductor materials and materials having similar properties.

DESCRIPTION OF SYMBOLS 1 Wire saw work rocking device 2 Wire saw 3 Processing roller 4 Wire 5 Work 5a Plate-like body surface 5b Vertex part 6 Support body 7 Feed screw 8 Feed screw 9 Feed nut 10 Feed nut 11 Drive motor 12 Drive motor 13 Controller 14 Adhesive 15 Fixing plate 16 Work plate 17 Thrust bearing 18 Thrust bearing 19 Holding shaft 20 Holding shaft 21 Bearing 22 Long groove bearing 22a Long groove 23 Input device 24 Frame T Time V Rotational speed V11 Rotational speed V12 of one drive motor Other drive motor Rotation speed

Claims (6)

  In a wire saw that feeds and moves a workpiece in a cutting direction with respect to a cutting area of a wire row that is traveling, and cuts the workpiece, support bodies that support the workpiece are arranged on one side and the other side in the traveling direction of the wire. Each feed screw is supported by a feed nut, and each feed screw is rotated by a corresponding drive motor to give the workpiece a feed movement in the cutting direction or the pulling direction, and one drive motor and the other drive motor A wire saw workpiece swinging method characterized in that a difference in feed amount per unit time is given by a rotational speed command between the two and a swing motion is given to the workpiece by the difference in feed amount per unit time. .   A speed waveform is formed by superposing wavy waveforms on a constant value, and the rotational speed command of one drive motor and the rotational speed command of the other drive motor are set by shifting the phase of the two speed waveforms. The method of rocking a workpiece of a wire saw according to claim 1.   A speed waveform is composed of a mountain-shaped waveform followed by 0 to a low value, and a command for the rotational speed of one drive motor and a command for the rotational speed of the other drive motor are made by shifting the phase of the two speed waveforms. 2. The wire saw workpiece swinging method according to claim 1, wherein the wire saw workpiece swinging method is set.   A velocity waveform is formed by repeating a waveform having a large chevron in the feed direction and a waveform having a small chevron in the return direction every predetermined time, and by shifting the phase of the two speed waveforms by a predetermined phase, 2. The wire saw workpiece swinging method according to claim 1, wherein a rotation speed command and a rotation speed command of the other drive motor are set.   A wire saw that feeds and moves a workpiece in a cutting direction to a cutting area of a traveling wire array and cuts the workpiece, and is provided on a support body that supports the workpiece, and one and the other in the traveling direction of the wire. A plurality of feed screws arranged in parallel to the cutting direction of the workpiece; a feed nut connected to each end of the support and fitted to the feed screw under a screw pair; and A plurality of drive motors for rotating each feed screw, and each of the drive motors is rotated to give a feed movement in the cutting direction or the drawing direction to the workpiece, and between one drive motor and the other drive motor. And a controller for giving a swinging motion to the workpiece by the difference in the feed amount per unit time. Work rocking device of Iyaso.   A feed nut at each end of the support is connected to a holding shaft for each end orthogonal to the traveling direction of the wire, and one end of the support is connected to the holding shaft by a bearing, 6. The wire saw work swinging device according to claim 5, wherein the other end of the support is connected to the holding shaft by a long groove bearing.

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