JP2012250328A - Wire saw device, workpiece cutting method, and manufacturing method for wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a constant wire deflection amount from the wire supply side to the wire collection side by reducing the tension of a wire on the wire supply side (new wire side), thereby making it possible to reduce the risk of the breaking of the wire and make the workpiece cutting ability uniform between the wire supply side and the wire collection side to thereby reduce variations in cut thickness.SOLUTION: A wire saw device 1 causes a cutting wire 4 wound around the outer peripheral grooves of a plurality of (here two) grooved rollers 2, 3 disposed at predetermined intervals to travel to cut a semiconductor ingot 7 that is a workpiece by a plurality of rows of the wire 4. The wire saw device comprises a tension control means 16 which, regarding the tension of the wire suspended between the groove rollers 2, 3, makes the tension of the wire on the wire collection side larger and the tension of the wire on the wire supply side smaller.

Description

  The present invention relates to a wire saw device for cutting a workpiece with a cutting wire by running a cutting wire passed through the outer periphery of a plurality of grooved rollers arranged at predetermined intervals, a workpiece cutting method using the same, and a wafer It relates to the manufacturing method.

  In this type of conventional wire saw apparatus, a workpiece is cut to produce a wafer material while controlling the tension of the wire stretched around the main roller. This is disclosed in Patent Documents 1 and 2.

  FIG. 17 is a perspective view schematically showing a configuration example of a main part of a conventional wire saw device disclosed in Patent Document 1. As shown in FIG.

  As shown in FIG. 17, a conventional wire saw device 200 mainly includes a fixed abrasive wire 201 for cutting a workpiece W, two grooved rollers 202 around which the fixed abrasive wire 201 is wound, Wire tension applying mechanisms 203A and 203B for applying tension to the abrasive wire 201, a workpiece feeding mechanism 204 for holding and cutting the workpiece W to be cut, and a cooling water supply for cooling the workpiece W to be cut And a mechanism 205.

  The fixed abrasive wire 201 is fed from the wire reel 206A on the supply side, and enters the grooved roller 202 via the wire tension applying mechanism 203A. The fixed abrasive wire 201 is wound around the grooved roller 202 about 300 to 400 times to form a wire row. The fixed abrasive wire 201 is wound around the wire reel 206B on the collection side through the other wire tension applying mechanism 203B.

  In this way, tension is applied to the fixed abrasive wire 201 wound around the grooved roller 202 by these wire tension applying mechanisms 203A and 203B, and the reversal cycle time set in the axial direction by the drive motor 207 is set for traveling. The workpiece W is reciprocated at a speed, pressed against the fixed abrasive wire 201 that reciprocates the workpiece W, and cut and fed to cut the workpiece W into a wafer shape.

  In the conventional wire saw device 200, the tension of the fixed abrasive wire 201 is managed by the wire tension applying mechanisms 203A and 203B on the new line supply side and the old line recovery side. The tension of the wire 201 is not managed. Patent Document 2 discloses that the tension of the fixed abrasive wire 201 is managed inside each grooved roller 202.

  FIG. 18 is a side view schematically showing a configuration example of a main part of a conventional wire saw device disclosed in Patent Document 2. As shown in FIG. FIG. 19 is a perspective view of three grooved rollers in the wire saw device of FIG.

  18 and 19, the conventional wire saw device 100 is provided with three grooved rollers 101 to 103 that are rotatable in parallel to the axial direction at a predetermined interval. A wire 104 is wound around each of the grooved rollers 101 to 103, and the winding shape is a triangle in a side view. Each of the grooved rollers 101 to 103 has a plurality of circumferential grooves 105 spirally formed at predetermined pitch intervals in a plane perpendicular to the rotation axis on the circumferential surface thereof.

  The wire 104 is wound between the grooved rollers 101 to 103 so that the wire 104 engages with the circumferential groove 105 having a predetermined pitch of each of the grooved rollers 101 to 103. At this time, the wire 104 wound around the circumferential groove 105 of the grooved rollers 101 to 103 is wound in multiple layers in a spiral shape. One of the wires 104 wound spirally between the grooved rollers 101 to 103 is wound around the supply reel 106, and the other is wound around the collection reel 107 to wind the wire 104. By driving the supply reel 106 and the recovery reel 107, the wire 104 wound around the grooved rollers 101 to 103 can be run.

  In order to give a required tension to the wire 104 wound around each of the grooved rollers 101 to 103, the tension is detected by the dancer rollers 108 and 109 outside the grooved rollers 101 to 103, and the supply reel 106 and the recovery reel 107 are The number of rotations is controlled so that the tension of the wire 104 outside the grooved rollers 101 to 103 is constant. The capstans 110 and 111 apply the braking to the wire 104 by winding the wire 104 a plurality of times.

  A tension holding means 112 that keeps the tension of the wire 104 constant by contacting the wire 104 spirally wound between the grooved rollers so that the tension of the wire 104 is constant also in each of the grooved rollers 101 to 103. Is provided. As shown in FIG. 18, the tension holding means 112 is installed in the vicinity of the wire 104 on the hypotenuse between the grooved roller 101 and the grooved roller 103 disposed at the apex position of the triangle, and the grooved roller 101. The two sides of the hypotenuse wire 104 between the roller and the grooved roller 102 are triangular outer sides.

The tension holding means 112 supports a tension applying member 113 that abuts on the wire 104, a shaft 114 that supports the tension applying member 113, a spring 115 that urges the tension applying member 113 to the wire 104 with a constant pressure, and supports the spring 115 and the shaft 114. The bottom wire 104 between the grooved roller 102 and the grooved roller 103, which is composed of the support member 116, serves as a workpiece cutting portion. While applying cooling coolant to the wire 104 serving as the cutting portion, for example, A workpiece 117 such as a semiconductor ingot as a workpiece is pressed. This pressing is performed by an elevating device 121 that elevates and lowers the stage 120 through the slide portion 119 by the driving device 118 and elevates the workpiece 117 fixed on the stage 120. By pressing the workpiece 117 against each wire 104 in which a large number of wires are arranged in parallel, cutting is performed by a lapping action, and at the same time, the workpiece 117 can be cut into a number of thin wafers. Thereby, a large number of wafer materials can be manufactured.

  The tension applying member 113 urged by the spring 115 with a constant pressure is brought into contact with the two wires 104 adjacent to the apex angle of the triangle that does not contribute to the cutting so that the tension of the wire 104 is always constant. keeping.

  As a result, tension higher than the tensile strength is applied to the wire 104 by the tension holding means 112, or the wire 104 is disconnected, or the winding force of the wire 104 around the grooved rollers 101 to 103 is weakened to cut the workpiece. The accuracy is not lowered, and the wire 104 is not detached from the circumferential groove 105 to cause a cutting failure.

  Thus, when the tension of the wire 104 in the cutting portion is kept constant, a large number of brittle materials such as a semiconductor material, a magnetic material, and a ceramic material can be simultaneously cut into a wafer with high accuracy.

  The tension applying member 113 uses a plurality of contact rollers that individually contact each wire 104, and a circumferential groove that engages the wire 104 is provided on the peripheral surface thereof. In this way, since the tension of each wire 104 can be individually adjusted, there is no lateral deflection of the wire 104, and the wafer cutting accuracy can be further improved.

JP 2011-20197 A Japanese Patent Laid-Open No. 7-276218

  In the conventional wire saw device 100 disclosed in Patent Document 2, the tension of the wire 104 is managed by the dancer rollers 108 and 109 on the new line supply side and the old line collection side, and the wire is also provided inside the grooved rollers 101 to 103. The tension of the wire 104 is managed by the tension holding means 112 so that the tension of 104 is constant.

  In this case, since the abrasive grains fixed to the wire 104 are worn by friction with the workpiece, as shown in FIG. 20, the abrasive grains are cut well toward the new line side and from the wire supply side (new line side) in the width direction of the workpiece. The sharpness decreases as it goes to the wire collection side (old line side). Therefore, when the workpiece is pressed against the wire 104 with a certain force, a difference occurs in the amount of bending of each of the wires 104 stretched. That is, there is a problem that as the wire supply side is moved toward the wire collection side, the amount of bending of the wire is large and a strong tension is applied to the wire 104, causing blurring and reducing the processing accuracy. In addition, when the wire 104 is cut, the joints of the wire 104 and the temperature of the work 117 are also cooled and the cutting method is changed, resulting in a step. Therefore, there is a problem that it is necessary to replace the work 117 and the wire 104 together.

  The present invention solves the above-described conventional problems, and reduces the wire tension on the wire supply side (new line side) to reduce the wire deflection amount variation from the wire supply side (new line side) to the wire recovery side (old line). This reduces the risk of wire breakage and reduces the cutting thickness of the wire supply side (new line side) and the wire recovery side (old line side). It is an object of the present invention to provide a wire saw device capable of reducing variations, a workpiece cutting method using the same, and a wafer manufacturing method.

  The wire saw device of the present invention is a wire saw device that travels a cutting wire wound around an outer peripheral groove of a plurality of grooved rollers arranged at a predetermined interval and cuts a workpiece by a plurality of rows of the wire. Among the wire tensions stretched between the grooved rollers, tension control means is provided that increases the wire tension on the wire recovery side and decreases the wire tension on the wire supply side, thereby achieving the above object. Is done.

  Preferably, the tension control means in the wire saw device of the present invention maximizes the wire tension on the wire collection side, and the tension is stepwise for each one or a plurality of wires from the wire collection side to the wire supply side. The tension is maintained in a state where is reduced.

  Further preferably, in the wire saw device according to the present invention, the wire tension on the wire supply side is reduced as compared with the wire tension on the wire collection side, and the amount of bending of the wire extends from the wire supply side to the wire collection side. Is held constant.

  Further preferably, in the wire saw device of the present invention, the wire row surface for cutting the workpiece and the wire row surface with which the tension control means abuts are different wire row surfaces.

  Further preferably, one or a plurality of tension control means are provided in the wire saw device of the present invention, and the tension is controlled to a plurality of stages equal to or less than the number of wires in the plurality of rows of the wires in two or more stages.

  Still preferably, in a wire saw device according to the present invention, the tension control means sets the wire tension in a plurality of stages from the wire recovery side to the wire supply side.

  Further preferably, the tension control means in the wire saw device of the present invention includes a plurality of sub-roller groups in contact with each wire, a shaft member that rotatably supports the plurality of sub-roller groups, and a support member that supports the shaft member, One or a plurality of urging members for urging the sub-roller group to each of the wires with a constant pressure is provided, and the plurality of sub-roller groups are collectively pressed against the wires.

  Further preferably, in the wire saw device of the present invention, the diameter of the sub-roller is gradually reduced for each sub-roller group or each sub-roller of the sub-roller group from the wire collection side to the wire supply side. ing.

  Further preferably, the tension control means in the wire saw device of the present invention comprises a sub-roller group that abuts on each of the wires, a shaft member that rotatably supports the sub-roller group, a support member that supports the sub-roller group, and the sub-roller group And a plurality of urging members for urging each of the wires with a constant pressure, and each of the plurality of sets of sub-rollers is independently pressed against each of the wires.

  Further preferably, in the wire saw device of the present invention, the pushing force or the pushing amount of each of the sub-roller groups to the respective wires of the sub-roller group gradually decreases from the wire collection side to the wire supply side for each sub-roller group. It is configured.

  Further preferably, in the wire saw device of the present invention, the wire tension is gradually reduced for each of the sub-roller groups from the wire recovery side to the wire supply side.

  Furthermore, preferably, in the wire saw device of the present invention, the wire tension is gradually reduced for each sub-roller of the sub-roller group from the wire recovery side to the wire supply side.

  Further preferably, the wire saw device according to the present invention further comprises a deflection amount detecting means for detecting the deflection amount of the wire between the grooved rollers, and the tension control means is configured so that the deflection amount of the wire is recovered from the wire supply side. Depending on the deflection amount detected by the deflection amount detecting means so as to reduce the variation in the deflection amount of the wire from the wire supply side to the wire recovery side. A pressurization control unit that pressurizes each of the wires is provided.

  The workpiece cutting method of the present invention is a workpiece cutting method using the above-described wire saw device of the present invention, and sets the wire tension of the wire stretched between the grooved rollers by cutting the test workpiece. The method includes a setting step and a workpiece cutting step of cutting an actual workpiece using the set wire tension, whereby the above object is achieved.

  Preferably, in the wire tension setting step in the workpiece cutting method of the present invention, the wire tension is controlled by operating the tension control means based on the displacement of the wire deflection amount detected during the cutting of the test workpiece. By doing so, the wire tension on the wire supply side is reduced compared to the wire tension on the wire collection side, and the amount of wire deflection is held constant from the wire supply side to the wire collection side, or The wire tension is set by adjusting the wire tension so as to reduce the variation in the deflection amount of the wire from the wire supply side to the wire recovery side.

  The workpiece cutting method of the present invention is a workpiece cutting method using the above-described wire saw device of the present invention, and a wire tension setting step of automatically setting the wire tension of the wire stretched between the grooved rollers; And a workpiece cutting step of cutting an actual workpiece using the set wire tension, whereby the above object is achieved.

  Further preferably, the wire tension setting step in the workpiece cutting method of the present invention is configured such that the wire tension on the wire supply side is changed to the wire recovery side based on the displacement of the wire deflection amount detected during the actual workpiece cutting. The wire bending amount is kept constant from the wire supply side to the wire recovery side, or variation in the wire bending amount is reduced from the wire supply side to the wire recovery side. The tension control means automatically controls the wire tension to set the wire tension so as to decrease over the side.

  The wafer manufacturing method of the present invention is the above-described workpiece cutting method of the present invention, wherein the workpiece is a semiconductor ingot, and the semiconductor ingot is cut into a plurality of semiconductor wafers by a wire row of the wire saw device. This achieves the above object.

  With the above configuration, the operation of the present invention will be described below.

  In the present invention, in a wire saw device for cutting a work in a plurality of rows of wires by running each wire for cutting wound around an outer peripheral groove of a plurality of grooved rollers arranged at predetermined intervals, a plurality of grooves are provided. Among the wire tensions stretched between the rollers, there is a tension control means that increases the wire tension on the wire recovery side and decreases the wire tension on the wire supply side.

  This reduces the wire tension on the wire supply side (new line side) and reduces the wire deflection variation from the wire supply side (new line side) to the wire recovery side (old line side). In addition to suppressing the risk of disconnection, the workpiece cutting ability can be made uniform on the wire supply side (new line side) and the wire recovery side (old line side), and variations in cutting thickness can be reduced.

  As described above, according to the present invention, the wire tension is reduced from the wire supply side (new line side) to the wire recovery side (old line side) by reducing the wire tension on the wire supply side (new line side). By reducing, the risk of wire breakage can be suppressed, and the work cutting ability can be made uniform on the wire supply side (new line side) and the wire recovery side (old line side), and variations in cutting thickness can be reduced. .

It is a perspective view which shows typically the example of a principal part structure of the wire saw apparatus in Embodiment 1 of this invention. It is the top view which looked at the state by which the wire was wound between the grooved rollers of the wire saw apparatus of FIG. 1 from the top. It is a side view which shows an example of the principal part structure of the wire saw apparatus of FIG. It is a top view which shows an example of the principal part structure of the wire saw apparatus of FIG. It is a block diagram which shows an example of the tension control means of FIG. It is a top view which shows an example of the principal part structure of the wire saw apparatus of FIG. It is a block diagram which shows another example of the tension control means of FIG. It is a side view which shows typically the example of a principal part structure of the wire saw apparatus containing the modification of the tension control means of FIG. (A) is a side view which shows typically the modification of the wire saw apparatus in Embodiment 1 of this invention, (b) is the side view which shows the further modification of the wire saw apparatus of (a) typically It is. It is a block diagram which shows an example of the tension control means of FIG. It is a block diagram which shows another example of the tension control means of FIG. It is a longitudinal cross-sectional view of the workpiece | work and wire which show typically how to cut | disconnect the workpiece | work by the wire at the time of setting the tension | tensile_strength for every wire. It is a longitudinal section of a work and a wire which shows typically how to cut a work with a wire when tension of a wire is set up in two steps. It is a side view which shows typically the example of a principal part structure of the wire saw apparatus in Embodiment 3 of this invention. It is a top view which shows typically the principal part structural example of the wire saw apparatus of FIG. It is a block diagram which shows an example of the tension control means of FIG. 14 and FIG. It is a side view which shows typically the example of a principal part structure of the conventional wire saw apparatus currently disclosed by patent document 1. FIG. FIG. 18 is a perspective view of three grooved rollers in the wire saw device of FIG. 17. It is a perspective view which shows typically the example of a principal part structure of the conventional wire saw apparatus currently disclosed by patent document 3. FIG. It is a longitudinal cross-sectional view of the semiconductor ingot and the wire which show typically how to cut the work with the wire of the conventional wire saw device.

  Hereinafter, Embodiments 1 and 3 of the wire saw device of the present invention and Embodiment 2 of a workpiece cutting method using Embodiment 1 of the wire saw device of the present invention will be described in detail with reference to the drawings. In addition, each thickness, length, etc. of the structural member in each figure are not limited to the structure to illustrate from a viewpoint on drawing preparation.

(Embodiment 1)
FIG. 1 is a perspective view schematically showing a configuration example of a main part of a wire saw device according to Embodiment 1 of the present invention.

  In FIG. 1, a wire saw device 1 according to the first embodiment has a plurality of (here, two) grooved rollers 2 and 3 arranged horizontally at a predetermined interval. The rotating shafts of the two grooved rollers 2 and 3 are parallel to each other in the axial direction, and are rotatably provided with an outer peripheral groove outside the rotating shaft. Each of the grooved rollers 2 and 3 has a plurality of outer circumferential grooves formed in a spiral shape on the circumferential surface at a predetermined pitch interval. A cutting wire 4 is wound around the outer peripheral grooves of the plurality of grooved rollers 2 and 3 arranged at a predetermined interval.

  The wires 4 wound around the outer peripheral grooves of the grooved rollers 2 and 3 are wound in a spiral manner in multiple layers. When the number of windings between the grooved rollers 2 and 3 is large, the number is several thousand. One end of the wire 4 wound spirally between the grooved rollers 2 and 3 is wound around the supply reel 5 on the new line supply side, and the other end is wound around the recovery reel 6 on the old line collection side. By driving the supply reel 5 and the recovery reel 6, the wire 4 wound between the grooved rollers 2 and 3 is caused to travel so that a plurality of workpieces 7 (here, semiconductor ingots) are simultaneously formed in a plurality of rows of the wires 4. It is designed to cut. When there are many cut sheets, several thousand sheets are cut simultaneously. The wire 4 has a core wire diameter of, for example, 50 μm to 500 μm here, and abrasive grains such as diamond are fixed around the core wire. For example, when the diameter of the wire 4 is 50 μm (0.05 mm), the cutting margin is ideally about 50 μm (0.05 mm). For example, several tens to several hundreds Km of wire 4 is wound around the supply reel 5.

  In order to give a required tension to the wire 4 wound around each grooved roller 2, 3, inertia driven guide rollers 8, 9 are provided between the grooved roller 2 and the supply reel 5, and the guide rollers 8, 9 are provided. A dancer roller 10 is provided between the two. The dancer roller 10 controls the tension of the wire 4 to the grooved roller 2 to be constant. In addition, inertia driven guide rollers 11 and 12 between the grooved roller 3 and the collection reel 6 are provided, and a dancer roller 13 is provided between the guide rollers 11 and 12. The tension of the wire 4 from the grooved roller 3 is controlled to be constant by the dancer roller 13. In short, the dancer rollers 10 and 13 are provided between the guide rollers 8 and 9 and the guide rollers 11 and 12 for changing the direction of the wire 4, and a constant urging force acts downward and a constant tension acts on the wire 4. It is supposed to be. The wire tension by the dancer roller 13 on the old line side is the maximum, and the wire tension by the dancer roller 10 on the supply side is lower than the wire tension on the collection side (for example, 70 to 95 percent).

  A traverser 14 is provided between the guide roller 9 and the supply reel 5 so that the wires 4 aligned and wound around the supply reel 5 by the traverser 14 are sequentially taken out. A traverser 15 is also provided between the guide roller 12 and the collection reel 6, and acts so that the wire 4 is wound up in alignment with the collection reel 6 by the traverser 15.

  The supply-side traverser 14 has a function of smoothly moving up and down to the wire position when the wire 4 is taken from the supply reel 5 and smoothly taking out the wire 4 that has been aligned and wound. Further, the traverser 15 on the collection side has a function of moving the collection reel 6 up and down sequentially to wind the wires 4 smoothly and sequentially in order to wind the wires 4 in an aligned manner.

  In each grooved roller 2, 3, a tension that controls the tension of the wire 4 by contacting a large number of wires 4 spirally wound between the grooved rollers 2, 3 so that the tension of the wire 4 can be controlled. Control means 16 is provided. The lower wire row surface with which the tension control means 16 abuts is a wire row surface different from the upper wire row surface that cuts the workpiece 7. Thus, by providing the tension control means 16 at a place different from the work cutting part (semiconductor ingot side), the influence of the wire height deviation due to the tension control on the work cutting can be reduced. Here, the wire row surface indicates the upper and lower planes formed by the wire row between the grooved rollers 2 and 3.

  The tension control means 16 increases the tension of the wire 4 on the wire recovery side (old line side) in at least two stages of the tension of the wire 4 stretched between the grooved rollers 2 and 3, and the wire supply side The tension of the wire 4 on the (new line side) is set small. Further, the tension control means 16 maximizes the tension of the wire 4 on the wire collection side (old line side), and one or a plurality of wires from the wire collection side (old line side) to the wire supply side (new line side). The tension of the wire 4 is maintained in a state where the tension of the wire 4 is reduced step by step. In this case, the tension of the wire on the wire supply side (new line side) is reduced.

  The upper wire row surface of the wire 4 between the grooved rollers 2 and 3 is a cut surface of the workpiece 7, and a machining liquid supply unit 20 is provided so as to cross the cut surface left and right. For example, the workpiece 7 is pressed against the wire row surface of the cutting surface and cut while applying coolant for cooling from the processing liquid supply port of the processing liquid supply unit 19. The workpiece 7 is simultaneously cut into a wafer by a large number of wires 4 while applying a liquid coolant to the workpiece 7 and each wire 4 for the purpose of cooling.

  The workpiece 7 is pressed against the wire row by moving up and down the fixed portion 17 to which the workpiece 7 is fixed by the workpiece feeding mechanism 18 and pressing the workpiece 7 against the wire row between the grooved rollers 2 and 3 from above. By pressing the workpiece 7 onto the row of wires 4 in which a large number of wires are arranged in parallel, the workpiece 7 is simultaneously cut into a large number of thin wafers having a uniform thickness. As a result, a wafer material having a uniform thickness can be manufactured.

  The processing chamber accommodates the grooved rollers 2 and 3, the wire 4 between them, the tension control means 16, the work 7, the fixing portion 17 that fixes the work 7, and the work feeding mechanism 18, and other members are outside the processing chamber. Is arranged.

  FIG. 2 is a plan view of the state in which the wire 4 is wound between the grooved rollers 2 and 3 of the wire saw device 1 of FIG.

  As shown in FIG. 2, among a large number of wires 4 stretched between the grooved rollers 2 and 3, at least two stages of the wire recovery side (old line side) A and the wire supply side (new line side) B The tension control means 16 increases the tension of the wire 4 on the wire recovery side (old line side) A and sets the tension of the wire 4 on the wire supply side (new line side) B small. Here, the ratio between the wire recovery side (old line side) A and the wire supply side (new line side) B is set to 1: 2 (1/3 and 2/3 of the whole). The ratio of the wire recovery side (old line side) A and the wire supply side (new line side) B is not limited to 1: 2, but is 1: 1 (1/2 and 1/2 of the whole) with the center line as a boundary. However, other ratios may be used. Further, the tension control means 16 maximizes the tension of the wire 4 on the wire collection side (old line side), and increases from the end of the wire collection side (old line side) A toward the wire supply side (new line side). Or you may make it hold | maintain the tension | tensile_strength of the wire 4 in the state which decreased the tension | tensile_strength of the wire 4 for every some wire 4 in steps. In short, one or a plurality of tension control means 16 are provided, and the tension is controlled in two or more stages to the number of wires in the wire row or less. As a result, a tension gradation equal to or less than the number of wires in the wire row is obtained in two or more stages.

   Here, as the tension control means 16, a connecting sub-roller that presses the lower wire 4 between the grooved rollers 2 and 3 at two left and right locations along the wire 4 will be described with reference to FIGS. 3 and 4.

  FIG. 3 is a side view showing an example of a configuration of a main part of the wire saw device 1 of FIG. FIG. 4 is a plan view showing an example of a main configuration of the wire saw device 1 of FIG. FIG. 5 is a block diagram showing an example of the tension control means 16 of FIG.

  As shown in FIGS. 3 to 5, the tension control means 16 includes a shaft member that rotatably supports five sub-roller groups that abut each wire 4, and five grooved sub-roller groups, and a support that supports the shaft member. A member and a biasing member that biases the grooved sub-roller group to each wire 4 with a constant pressure, and the five sub-roller groups may be collectively pressed against each wire 4, The tension to each wire 4 is divided into five stages. The tension control means 161A of the connected sub-roller having three sub-roller groups provided between the work 7 and the grooved roller 2 in plan view, and the work in plan view. 7 and a connected sub-roller tension control means 161B having two sub-rollers provided between the grooved roller 3 and the sub-roller 3.

  The tension control means 161A includes grooved sub-rollers 161a, 161c, and 161e serving as tension applying members that contact each wire 4, a shaft member that rotatably supports the grooved sub-rollers 161a, 161c, and 161e, and a shaft member that supports the shaft member. A spring 161g for urging the shaft member 161f to urge the sub-rollers 161a, 161c and 161e with grooves as tension applying members to each wire 4 with a constant pressure; a spring 161g and the shaft member; A support member 161h for supporting 161f, and the grooved sub-rollers 161a, 161c and 161e (three sub-roller groups) are collectively pressed against each wire 4; The spring 161g and the support member 161h constitute the urging member.

  Divided into a wire row range for applying wire tension in the first to fifth stages from the wire recovery side (old line side) to the wire supply side (new line side), and the grooved sub-roller 161a is the oldest Corresponding to the first wire row range on the wire side, the grooved sub-roller 161c corresponds to the third wire row range located in the middle, and the grooved sub-roller 161e is the fifth wire wire side (new line side). Corresponds to the wire row range. When the diameter of the grooved sub-roller 161a is R1, the diameter of the grooved sub-roller 161c is R3, and the diameter of the grooved sub-roller 161e is R5, R1> R3> R5. The grooved sub-rollers 161a, 161c and 161e, which are three sub-roller groups having different diameters, are configured to be collectively pressed against each wire 4 via a common shaft member. In this case, as the old wire side has a larger diameter, the old wire side has a larger push-in amount and can be pressed against each wire 4 with a strong tension.

  The tension control means 161B is a support member composed of grooved sub-rollers 161b and 161d as tension applying members that abut each wire 4, a shaft member that rotatably supports the grooved sub-rollers 161b and 161d, and a shaft member that supports the shaft member. And a spring for urging the grooved sub-rollers 161b and 161d as tension applying members to each wire 4 with a constant pressure, and a support member for supporting the spring and the shaft member. These springs and the supporting member constitute the urging member.

  The grooved sub-roller 161b corresponds to the second wire row range on the old line side, and the grooved sub-roller 161d corresponds to the fourth wire row range on the new line side. When the diameter of the grooved sub-roller 161b is R2 and the diameter of the grooved sub-roller 161d is R4, R2> R4 and R1> R2> R3> R4> R5. The grooved sub-rollers 161b and 161d, which are two sub-roller groups having different diameters, can be collectively pressed against each wire 4 via a common shaft member. In this case, as the old wire side has a larger diameter, the old wire side has a larger push-in amount and can be pressed against each wire 4 with a strong tension.

  In the above case, the tension control means 161A and 161B applies a tension higher than the tensile strength to the wire 4 and the wire 4 is broken, or the winding force of the wire 4 around the grooved rollers 2 and 3 is weakened. Thus, the tension of the wire 4 is set so that the workpiece cutting accuracy does not decrease or the wire 4 is not detached from the outer peripheral groove and causes a cutting failure. The tension of the wire 4 is set based on the breaking strength (tensile strength) of the wire 4.

  As described above, the three grooved sub-rollers 161a as the tension applying members of the tension control means 161A, in which the tension control means 161A and 161B are collectively pressed against each wire 4 and the wire tension is varied depending on the difference in sub-roller diameter, 161c and 161e, and the two grooved sub-rollers 161b and 161d have been described as tension applying members of the tension control means 161B. As another example, by using FIG. 6 and FIG. The grooved sub-rollers 161a, 161b, 161c, 161d, and 161e will be described as tension applying members of the five tension control means 162 that have different wire tensions depending on the roller pressing amount (roller pressing force).

   Further, as the tension control means 16, an unconnected sub-roller that presses the lower wire 4 between the grooved rollers 2 and 3 at two left and right locations along the wire will be described.

  FIG. 6 is a plan view showing another example of the main configuration of the wire saw device 1 of FIG. FIG. 7 is a block diagram showing another example of the tension control means 16 of FIG.

  As shown in FIGS. 6 and 7, the tension control means 16 has a tension applied to each wire 4 divided into five stages, and is provided between the workpiece 7 and the grooved roller 2 in a plan view, and is independent of each other. Three tension control means 162 each having a grooved sub-roller 162a, 162c, 162e that move and a grooved sub-roller 162b and 162d that are provided between the workpiece 7 and the grooved roller 3 in a plan view and move independently. Two tension control means 162 having a plurality of (5) sub-roller groups independently driven, and among the divided five grooved sub-rollers 162a, 162b, 162c, 162d, 162e, the most From the wire collection side (old wire side), the wire tension is maximized by pushing the wire collection side (grooved sub-roller 162a) to the maximum (pushing force). Each wire 4 is held so that the tension of the wire 4 is maintained in a state where the pushing amount (pushing force) is gradually reduced toward the ear supply side (new line side) and the tension of the wire 4 is gradually reduced. Press.

  The tension control means 162 includes a grooved sub-roller of the sub-roller group that abuts on each wire 4, a shaft member that rotatably supports the grooved sub-roller and a support member that supports the grooved sub-roller, and a grooved sub-roller group with a constant pressure. And a biasing member that biases each wire 4 and presses each of the wires 4 independently of the grooved sub-rollers 162a, 162b, 162c, 162d, 162e of the sub-roller group.

  For example, the tension control means 162 on the most wire recovery side (old line side) includes a grooved sub-roller 162a as a tension applying member that contacts each wire 4, a shaft member that rotatably supports the grooved sub-roller 162a, and this A spring 162g for urging the shaft member 162f to urge each wire 4 with a predetermined pressure (pushing force), and a spring 162g. And a support member 162h that supports the shaft member 162f. The other tension control means 162 has the same configuration. The biasing member is constituted by the spring 162g and the support member 162h.

  The pushing force to each wire 4 by the springs 162g of the five tension control means 162 gradually decreases from the wire recovery side (old line side) to the wire supply side (new line side). In short, the grooved sub-roller 162a is positioned closest to the wire recovery side (old line side), and the grooved sub-roller 161e is positioned closest to the wire supply side (new line side). The grooved sub-roller 162a has the largest pushing amount (pushing force), and the grooved sub-rollers 162a to 162e gradually decrease the pushing amount (pushing force) toward the wire supply side (new line side). Are gradually reduced.

  In the above case, the five tension control means 162 applies a tension higher than the tensile strength to the wire 4 and the wire 4 is disconnected, or the winding force of the wire 4 around the grooved rollers 2 and 3 is weak. Thus, the tension of the wire 4 is set so that the wafer cutting accuracy does not decrease or the wire 4 is not detached from the outer peripheral groove and causes a cutting failure. The tension of the wire 4 is set based on the breaking strength (tensile strength) of the wire 4.

  Further, when the tension control means 16 is a non-connected sub-roller that presses the lower wire 4 between the grooved rollers 2 and 3 at two positions on the left and right sides, five pieces having the same roller diameter as described above and varying the pushing amount are used. Referring to FIG. 11, instead of the tension control means 162a to 162e, the five tension control means are configured so that the roller diameter changes stepwise (stepwise) or continuously (tapered), respectively. May be. In this case, the roller diameter decreases stepwise (stepwise) or continuously (tapered) as it goes to the wire supply side (new line side) in both one tension control means and all five tension control means. The tension of the wire 4 may be sequentially reduced toward the wire supply side. In this case, in the five tension control means, the pushing amount (pushing force) is constant or the change width can be reduced so as not to change so much. In short, the tension of the wire 4 on the wire collection side can be increased and the tension of the wire 4 on the wire supply side can be decreased by combining the change in the roller diameter and the change in the pushing amount.

  Referring to FIG. 11, each of the five tension control means includes a grooved sub-roller composed of a sub-roller group 23a that contacts each wire 4, a shaft member that rotatably supports the grooved sub-roller group 23a, and the shaft member. A support member including a shaft member 23b to be supported; a spring 23c for urging the sub-roller group 23a against each wire 4 with a constant pressure; and a support member 23d for supporting the spring 23c and the shaft member 23b. When pressing each wire 4 in a lump, stepwise (stepped) or continuous (tapered) for each grooved sub-roller from the wire recovery side (old line side) to the wire supply side (new line side) The wire tension can be reduced. These springs 23c and the support member 23d constitute an urging member. Here, the sub-roller group 23a presses one wire 4 with one grooved sub-roller to maximize the wire tension on the wire collection side, and for each wire 4 from the wire collection side to the wire supply side. The tension is held in a state where the tension is continuously reduced (tapered).

  The above five tension control means 162a to 162e and tension control means 161A and 161B are attached in an attachment mechanism so that the pushing amount of the grooved sub-roller with respect to each wire 4 can be adjusted.

  As described above, according to the first embodiment, the cutting wire 4 wound around the outer peripheral grooves of the plurality (two in this case) of the grooved rollers 2 and 3 arranged at a predetermined interval is caused to travel to the wire 4. In the wire saw device 1 that cuts the workpieces 7 in a plurality of rows, among the wire tensions stretched between the grooved rollers 2 and 3, the wire tension on the wire recovery side is increased and the wire tension on the wire supply side is decreased. A tension control means 16 is provided. That is, the tension control means 16 maximizes the wire tension on the wire collection side and holds the tension in a state where the tension is gradually reduced for each of the plurality of wires 4 from the wire collection side to the wire supply side.

  This reduces the tension of the wire 4 on the wire supply side (new line side) compared to the wire tension on the wire discharge side and maintains the state in which the variation in the amount of deflection of the wire 4 is reduced. In addition, the wire cutting ability can be made uniform on the wire supply side (new line side) and the wire discharge side (old line side), and variation in the cutting thickness of each wafer can be reduced.

  Here, generally, when the wire is thinned, the wire breaking strength decreases, and it is necessary to lower the upper limit of the wire tension that can be used in the apparatus. However, if the upper limit of the wire tension is lowered, the workability of the workpiece decreases, and the wire The difference in tension, in other words, the variation in the cutting thickness of each wafer described above appears more remarkably. Therefore, when using a thin wire (especially when using a wire having a small breaking strength such that the core wire diameter of the wire 4 is 80 μm or less), a greater effect can be obtained over the conventional device by controlling as in the present invention. Can do.

  In particular, the tension of the wire 4 on the wire supply side (new line side) is reduced because the wire 4 on the wire supply side (new line side) is well cut, so there is a high possibility of widening the cutting margin. By reducing the tension of the wire 4 on the side (new line side), the work cutting ability can be made uniform, and variations in the cutting thickness of each wafer can be reduced. Similarly, since the wire 4 on the wire collection side is not cut well, there is a high possibility that the cutting margin will be widened. By increasing the tension of the wire 4 on the wire collection side (old line side), The wire cutting ability can be made uniform, and variations in the cutting thickness of each wafer can be reduced. In short, the wire 4 can be similarly cut from the wire supply side (new line side) to the wire recovery side (old line side).

  Next, as described above, the two (or more) tension control means 16 divided into the left and right along the wire 4 are provided. However, the present invention is not limited to this, and a modification of the tension control means 16 is provided. 9 and 10, the connecting sub-roller that presses the lower wire 4 between the grooved rollers 2 and 3 along the wire 4 at one location will be described.

  Here, the case where one tension control means 22 to be described later is provided along the wire 4 will be described in detail with reference to FIG. 9A and FIGS.

  Fig.9 (a) is a side view which shows typically the modification of the wire saw apparatus in Embodiment 1 of this invention. In FIG. 9A, the same member numbers are used for the description of the structural members that exhibit the same operational effects as the structural members of FIG. FIG. 10 is a block diagram showing an example of the tension control means of FIG.

  9A and 10, a wire saw device 1 </ b> A, which is a modification of the first embodiment, has a plurality (here, two) of grooved rollers 2 and 3 arranged horizontally at a predetermined interval. . The rotating shafts of the two grooved rollers 2 and 3 are provided so that the axial directions thereof are parallel to each other and the outer peripheral grooves outside the rotating shaft can be rotated. Each of the grooved rollers 2 and 3 has a plurality of outer circumferential grooves formed in a spiral shape on the circumferential surface thereof at a predetermined pitch interval (for example, 0.3 mm). A cutting wire 4 is wound around the outer peripheral grooves of the two grooved rollers 2 and 3 arranged at a predetermined interval. The wire 4 wound between the grooved rollers 2 and 3 is caused to travel, and a plurality of workpieces 7 (here, semiconductor ingots) are simultaneously cut by a plurality of rows of the wires 4.

  The difference from the first embodiment is that the tension direction along the wire 4 is replaced with two (or more) tension control means 16 divided in the tension direction along the wire 4. The point is that one tension control means 22 is provided.

  The tension control means 22 is provided on the wire surface opposite to the workpiece 7 between the grooved roller 2 and the workpiece 7 in plan view. The tension control means 22 is rotatably supported by a grooved sub-roller composed of six sub-roller groups 22a to 22f having different diameters in contact with each wire 4 and the six grooved sub-roller groups 22a to 22f. And a supporting member comprising a shaft member 22g that supports the shaft member and a biasing member 22h that biases the six sub-roller groups 22a to 22f to each wire 4 with a constant pressure, and includes six sub-roller groups. 22a-22f is pressed to each wire 4 collectively.

  The grooved sub-rollers 22a to 22f are divided into wire row ranges that apply wire tension to a plurality of first to sixth stages from the wire recovery side (old line side) to the wire supply side (new line side). The grooved sub-roller 22a corresponds to the first wire row range on the oldest line side, and the grooved sub-roller 22f corresponds to the sixth wire row range on the most new line side. The diameter of the grooved sub-roller 22a is R1, the diameter of the grooved sub-roller 22b is R2, the diameter of the grooved sub-roller 22c is R3, the diameter of the grooved sub-roller 22d is R4, the diameter of the grooved sub-roller 22e is R5, and the diameter of the grooved sub-roller 22f When the diameter is R6, R1> R2> R3> R4> R5> R6. The sub roller groups 22a to 22f having different diameters can be collectively pressed against the wires 4 via a common shaft member. In this case, as the roller diameter is larger on the old line side, the wire 4 can be pressed against the wire 4 with stronger tension on the old line side.

  In the above case, the tension control means 22 applies a tension higher than the tensile strength to the wire 4 to break the wire 4 or the winding force of the wire 4 around the grooved rollers 2 and 3 is weakened. The tension | tensile_strength of the wire 4 is set so that a cutting precision may not fall or the wire 4 may remove | deviate from an outer periphery groove | channel and cause a cutting defect. The tension of the wire 4 is set based on the breaking strength (tensile strength) of the wire 4.

  The above tension control means 22 is attached in an attachment mechanism so that the pushing amount of the grooved sub-roller with respect to each wire 4 can be adjusted.

  As described above, according to the modification of the first embodiment, the cutting wire 4 wound around the outer peripheral grooves of the plural (here, two) grooved rollers 2 and 3 arranged at predetermined intervals is caused to travel. In the wire saw apparatus 1A for cutting the workpieces 7 that are workpieces in a plurality of rows of wires 4, the wire tension on the wire recovery side is increased among the wire tensions stretched between the grooved rollers 2 and 3, and the wire supply side Tension control means 22 having a reduced wire tension. That is, the tension control means 22 keeps the tension in a state where the wire tension on the wire collection side is maximized and the tension is continuously reduced for each wire 4 from the wire collection side to the wire supply side.

  This reduces the tension of the wire on the wire supply side (new line side) and reduces the variation in the amount of bending of the wire from the wire supply side (new line side) to the wire recovery side (old line side) or In order to keep the wire constant, the risk of wire breakage is suppressed, and the wire cutting ability can be made uniform on the wire supply side (new line side) and wire recovery side (old line side), thereby reducing variations in the cutting thickness of each wafer. Can be reduced.

  In the first embodiment, the case where a semiconductor ingot (for example, a single crystal or polycrystalline silicon ingot) of a semiconductor material is cut into a large number as the work 7 has been described. A large number of brittle materials such as materials can be simultaneously cut into a wafer with high accuracy.

  In the first embodiment, the three grooved sub-rollers 161a, 161c and 161e are used as tension applying members of the tension control means 161A which presses each wire 4 at once and changes the wire tension depending on the sub-roller diameter. The two grooved sub-rollers 161b and 161d will be described as tension applying members of the tension control means 161B, and as another example, the wire tension is made different depending on the amount of roller pressing by independently pressing the wire group. Although the grooved sub-rollers 161a, 161b, 161c, 161d and 161e have been described as tension applying members of the individual tension control means 162, the present invention is not limited to this, and instead of the grooved sub-roller having no friction with respect to the wire 4, FIG. As shown in FIG. 4, even if a pressing member 191 having a slight friction against the wire 4 is provided, There. Instead of the difference in the sub-roller diameter of the grooved sub-roller, the difference in wire tension may be caused by the difference in the thickness of the pressing member 191 (planar, stepped or tapered in the width direction of the wire row surface). A difference in wire tension may be caused by a difference in pressing amount (pressing force) of the pressing member 191 instead of a difference in pressing amount (pressing force) of the attached sub-roller. Furthermore, you may provide the pressing member 191 from which a thickness differs continuously or in steps from the end to the end of the wire row | line | column surface (from the wire supply side to the old line side of a wire collection | recovery side).

  In this case, the tension control means 19 includes a pressing member 191 as a tension applying member that comes into contact with each wire 4, and a holding member 192 that holds the pressing member 191 against one or a plurality of wires 4 so that the pressing amount can be adjusted. The controller 193 is a biasing member that biases the pressing member 191 as a tension applying member so that each wire 4 has a predetermined tension with a predetermined pressing amount.

  In the first embodiment, the wire row of the plurality of wires 4 is divided into five stages in the width direction, and the wire 4 is pressed by each of the grooved sub-rollers corresponding to the five stages. In the above description, the tension is held in a state where the tension is gradually reduced for each of a plurality of wires (5-step area) from the wire collection side to the wire supply side. First, the wire tension of the area on the wire collection side is obtained by pressing the wire 4 with each of the grooved sub-rollers corresponding to each area by dividing the area into 2 to 4 stages, further areas, or more than one stage. The tension may be held in a state where the tension is gradually reduced for each of the plurality of wires 4 (each area) from the wire recovery side to the wire supply side.

  In the first embodiment, in the case of FIG. 6, the tension to each wire 4 is divided into five stages, and the grooved sub-roller moves independently between the workpiece 7 and the grooved roller 2 in plan view. Three tension control means 162 each having 162a, 162c, 162e are provided, and two tensions each having grooved sub-rollers 162b and 162d that move independently between the workpiece 7 and the grooved roller 3 in plan view. Although the case where the control means 162 is provided has been described, the present invention is not limited to this, and the grooved sub-rollers 162a, 162b, 162c, 162d, and 162e that move independently are provided between the workpiece 7 and the grooved roller 2 in plan view, respectively. Five tension control means 162 may be provided. However, in actuality, the grooved sub-rollers 162a, 162b, 162c, 162d, and 162e that move independently of each other have different pushing forces (pushing amounts) on the wire 4 even though the roller diameter is the same. As long as they rotate independently in synchronization with each other, it is necessary to provide a certain gap between the adjacent grooved sub-rollers. When the distance between the wires 4 is 0.3 mm, for example, the certain gap is 0.3 mm. Yes, if you can: Here, three tension control means 162 and two tension control means 162 are arranged in front and rear positions. It is necessary that each tension control means 162 does not stick to the adjacent tension control means 162.

  In the case where each grooved sub-roller in FIG. 6 is pressed against each wire 4 independently, each grooved sub-roller having a different roller diameter in FIG. 4 is collectively pressed against each wire 4 via a common shaft member. It is more versatile than you do. That is, since the roller diameter is changed according to the tension setting of the wire 4, when the grooved sub-rollers having different roller diameters shown in FIG. 4 are collectively pressed against the wires 4 through the common shaft member, Although it may not be applicable to the wire 4 having a different core wire diameter, when each of the grooved sub-rollers in FIG. 6 is pressed against each wire 4 independently, the setting of the pushing amount (pushing force) This can be dealt with by simply changing the wire 4 according to the core diameter.

  In the modification of the first embodiment, the tension control unit 22 rotates the grooved sub-rollers including the six sub-roller groups 22a to 22f that are in contact with the wires 4 and the six grooved sub-roller groups 22a to 22f. A shaft member that freely supports the shaft and a support member that includes a shaft member 22g that supports the shaft member, and six biasing members that bias the six sub-roller groups 22a to 22f to each wire 4 with a constant pressure. When the sub-roller groups 22a to 22f are collectively pressed against the wires 4, the wire tension is applied in the first to sixth steps from the wire recovery side (old line side) to the wire supply side (new line side). However, the present invention is not limited to this, and as shown in FIG. 11, as tension control means 23, a grooved sub-roller composed of a sub-roller group 23 a that abuts on each wire 4, and a grooved sub-roller group 2 a support member comprising a shaft member that rotatably supports a and a shaft member 23b that supports the shaft member, a spring 23c that urges the sub-roller group 23a against each wire 4 with a constant pressure, and supports the spring 23c and the shaft member 23b. 23d for each grooved sub-roller from the wire collection side (old line side) toward the wire supply side (new line side) when the sub-roller group 23a is collectively pressed against each wire 4. The wire tension may be reduced continuously (tapered). These springs 23c and the support member 23d constitute an urging member. Here, the sub-roller group 23a presses one wire 4 with one grooved sub-roller to maximize the wire tension on the wire collection side, and for each wire 4 from the wire collection side to the wire supply side. The tension is maintained in a state where the tension is continuously reduced (tapered).

  FIG. 12 shows a longitudinal sectional view of the workpiece 7 and the wire 4 schematically showing how the workpiece 7 is cut by the wire 4 when tension is set for each wire (tapered). In this way, the wire tension on the wire supply side is reduced, and the amount of bending of the wire 4 is held constant from the wire supply side to the wire recovery side.

  FIG. 13 shows a longitudinal sectional view of the workpiece 7 and the wire 4 schematically showing how the workpiece 7 is cut by the wire 4 when the tension of the wire is set in two stages (stepped shape). In the case of FIG. 12 in which the tension is set for each wire, the wire supply side (new line side) and the wire recovery side (old line side) are set more than in the case of FIG. The wire cutting ability can be made more uniform, and the variation in the cutting thickness of each wafer can be further reduced.

  Although not specifically described in the first embodiment, each sub-roller group of the tension control means 16 that contacts each wire 4 is provided from the wire collection side to the wire supply side from end to end of the wire row surface. However, for each of the wires 4 on the wire collection side and the wire supply side where the tension of the wire 4 can be controlled by the dancer rollers 10 and 13, the sub-roller groups of the tension control means 16 contacting the wires 4 need not be arranged. Also good.

  In the first embodiment, the case where the two grooved rollers 2 and 3 are arranged horizontally at a predetermined interval has been described. However, the present invention is not limited to this, and the triangular vertex as shown in FIG. Three grooved rollers may be provided, and four grooved rollers may be provided at the apex of the quadrangle.

  Although not particularly described in the first embodiment, the grooved sub-rollers 161a, 161b, 161c, 161d, 161e, the grooved sub-rollers 162a, 162b, 162c, 162d, 162e, the sub-roller groups 22a to 22f, and the sub-roller group 23a However, the present invention is not limited to this, and it may be a grooveless sub-roller or a grooveless sub-roller group.

(Embodiment 2)
In the second embodiment, a workpiece cutting method for cutting the workpiece 7 into a large number of wafers using the wire saw devices 1 and 1A of the first embodiment will be described.

  The workpiece cutting method of the second embodiment includes a wire tension setting step of setting the wire tension of the wire 4 stretched between the grooved rollers 2.3 by cutting a test workpiece (semiconductor ingot similar to the workpiece 7). And a workpiece cutting step of cutting the actual workpiece 7 using the set wire tension. In this wire tension setting step, the wire tension on the wire supply side is controlled by operating the tension control means 16 or 22 based on the displacement of the wire deflection amount detected during the cutting of the test workpiece to control the wire tension. The wire tension is adjusted by adjusting the wire tension so that the wire deflection amount is kept constant from the wire supply side to the wire collection side. Here, the workpiece 7 is a semiconductor ingot, and the semiconductor ingot is cut into a plurality of semiconductor wafers in a slice shape by the wire row of the wire saw device 1 or 1A.

  Hereinafter, the workpiece cutting method according to the second embodiment will be described in more detail.

  First, a tension gradation is set by trial cutting with the test workpiece 7. Thereafter, the actual workpiece 7 is cut under the tension gradation cutting conditions. A gradation is added to the tension of the wire 4 to reduce variation in the amount of wire deflection during processing or to make the wire deflection amount constant. In short, the distribution of the deflection amount is reduced. Immediately after the wire is stretched, the entire surface of the main roller MR (grooved roller 2.3) is in a new line, and the situation is different from when it is continuously cut.

Here, a tension gradation setting method will be described.
(1) The wire 4 having a core wire diameter of 50 μm to 500 μm is stretched around the MR with the tension (eg, 10 N) of the dancer roller 10 on the new line side.
(2) The sub-rollers with all the grooves constituting the tension control means are brought into contact with the wires 4 so as to obtain the tension value on the old line side.
(3) One work piece 7 (semiconductor ingot) for testing is set on the fixed portion 17. The workpiece 7 is previously fixed to the fixing plate of the fixing portion 17 via an adhesive. The cutting depth of the work 7 is, for example, □ 125 mm and □ 156 mm.
(4) One semiconductor ingot 7 for test is sliced under actual slice conditions.
As an example of the slicing condition, new line supply amount: 5-30 m / min, cycle number: 0.5-4 cycle / min (Note that 1 cycle / min means reciprocating traveling in the forward path 30 sec / return path 30 sec), Ingot feed speed: 0.1-1.0 mm / min, wire travel speed: 500-1200 m / min.
(5) When the workpiece 7 is cut, for example, half or more, the slicing is interrupted and the amount of bending of the wire 4 is measured.
(6) By reducing the amount of contact with the sub-roller on the new line side, MR tension gradation is imparted and the deflection amount distribution of the wire 4 is reduced.
(7) Resume slicing of the test workpiece 7 and confirm the validity of the tension gradation.

  The tension gradation can be set by the above.

Next, a workpiece cutting process for cutting the actual workpiece 7 using the set tension gradation is performed.
(1) The wire 4 having a core wire diameter of 50 μm to 500 μm is stretched around the MR with the tension (eg, 10 N) of the dancer roller 10 on the new line side.
(2) The sub-rollers with all the grooves constituting the tension control means are brought into contact with the wires 4 so as to obtain the tension value on the old line side.
(3) One workpiece 7 to be actually cut is set on the fixing portion 17. The workpiece 7 is previously fixed to the fixing plate of the fixing portion 17 via an adhesive. The cutting depth of the work 7 is, for example, □ 125 mm and □ 156 mm.
(4) Slice one workpiece to be actually cut under actual slice conditions.
As an example of the slicing condition, new line supply amount: 5-30 m / min, cycle number: 0.5-4 cycle / min (Note that 1 cycle / min means reciprocating traveling in the forward path 30 sec / return path 30 sec), Ingot feed speed: 0.1-1.0 mm / min, wire travel speed: 500-1200 m / min.

  As a result, according to the second embodiment, the wire tension on the wire supply side (new line side) is reduced, and the variation in the amount of bending of the wire is changed from the wire supply side (new line side) to the wire recovery side (old line side). ) To reduce or keep the wire constant, the risk of wire breakage is suppressed, and the wire cutting ability can be made uniform on the wire supply side (new line side) and wire recovery side (old line side). Variations in wafer cutting thickness can be reduced.

  As a further modification of the wire saw device 1A that is a modification of the first embodiment, a deflection amount sensor 21 for controlling the workpiece feeding mechanism 18 may be provided.

  FIG.9 (b) is a side view which shows typically the further modification of 1 A of wire saw apparatuses of Fig.9 (a). In FIG. 9B, the same member numbers are used for the description of the structural members that exhibit the same effects as the structural members of FIG. 1 and FIG. 9A.

  As shown in FIG. 9B, the difference from the case of the wire saw device 1A of FIG. 9A is that a deflection amount sensor 21 for controlling the workpiece feeding mechanism 18 is provided.

  The deflection amount sensor 21 detects the deflection amount of the wire 4 in the cutting region of the workpiece 7, and fixes the workpiece 7 at the upper part and moves the workpiece 7 downward so that the detected deflection amount becomes a predetermined value or less. The workpiece feeding mechanism 18 that presses against each wire 4 is controlled. The workpiece feed amount of the workpiece feed mechanism 18 is controlled according to the wire deflection amount detected by the deflection amount sensor 21.

  The configuration in which the workpiece feed amount is controlled according to the deflection amount of the wire 4 using this deflection amount sensor 21 is not limited to the application to the configuration of FIG. 9A, and is pressed at two left and right locations along the wire. In addition to the connected sub-roller and the non-connected sub-roller of the first embodiment, it can be applied to all the sub-roller pressing configurations described in the first embodiment such as the pressing member 191 and the groove-less sub roller or the groove-less sub roller group of FIG. .

(Embodiment 3)
As described above, in contrast to the case where the workpiece feed amount is controlled according to the deflection amount of the wire 4 using the deflection amount sensor 21, in the third embodiment, the deflection amount sensor is used and the deflection amount of the wire 4 is determined. A case where the sub roller pressing amount is adjusted will be described.

  FIG. 14: is a side view which shows typically the example of a principal part structure of the wire saw apparatus in Embodiment 3 of this invention. FIG. 15 is a plan view schematically showing a configuration example of a main part of the wire saw device of FIG. In FIG. 14 and FIG. 15, the same member number is attached | subjected and demonstrated to the structural member which show | plays the same effect as the structural member of FIG. FIG. 16 is a block diagram showing an example of the tension control means of FIGS. 14 and 15.

  14 to 16, in the wire saw device 1B according to the third embodiment, a plurality of (here, two) grooved rollers 2 and 3 are horizontally arranged at a predetermined interval. The rotating shafts of the two grooved rollers 2 and 3 are provided so that the axial directions thereof are parallel to each other and the outer peripheral grooves outside the rotating shaft can be rotated. Each of the grooved rollers 2 and 3 has a plurality of outer circumferential grooves formed in a spiral shape on the circumferential surface thereof at a predetermined pitch interval (for example, 0.3 mm). A cutting wire 4 is wound around the outer peripheral grooves of the two grooved rollers 2 and 3 arranged at a predetermined interval. The wire 4 wound between the grooved rollers 2 and 3 is caused to travel, and a plurality of workpieces 7 (here, semiconductor ingots) are simultaneously cut by a plurality of rows of the wires 4.

  The difference from the first and second embodiments is that the bending amount sensor 24 as a bending amount detecting means for detecting the bending amount of each wire 4 and the tension control means 16 and 22 are provided at the front and rear, and are bent. This is the point that tension control means 25 for controlling the tension of the wire 4 based on the deflection amount of each wire 4 detected by the quantity sensor 24 is provided.

  The deflection amount sensors 24 are provided on the supply side and the recovery side of the wire 4 of the workpiece 7 and are provided for each wire row surface on which the tension control means 25 is disposed. The deflection amount sensor 24 detects the deflection amount of the wire 4 in the cutting region of the workpiece 7, and fixes the workpiece 7 at the upper part and moves the workpiece 7 downward so that the detected deflection amount is not more than a predetermined value. The workpiece feed mechanism 18 (not shown here) that presses against each wire 4 is controlled, and the detected value of the deflection amount of each wire 4 detected by the deflection amount sensor 24 is fed back to the corresponding tension control means 25.

  Here, a total of five tension control means 25 are arranged between the grooved roller 2 and the work 7 in a plan view and between the grooved roller 3 and the work 7 in a plan view. It is provided on the lower wire row surface opposite to the surface. Each of the tension control means 25 includes a grooved sub-roller 25a formed of a sub-roller group having the same diameter, which is in contact with each wire 4, a shaft member that rotatably supports the grooved sub-roller group, and a shaft member 25b that supports the shaft member. A support member, a spring 25c for biasing the shaft member 25b to bias the grooved sub-roller 25a as a tension applying member to each wire 4 with a predetermined pressure (pushing force), and the spring 25c and the shaft member 25b are supported. A pressure sensor 25e for detecting a pressing force (pushing amount) for pushing the grooved sub-roller 25a through the support member 25d, the spring 25c, and a predetermined value corresponding to the detected value of the bending amount of each wire 4 detected by the bending amount sensor 24. The spring 25c is applied via the pressure sensor 25e until the pressure value is detected by the pressure sensor 25e. And a pressing stage 25f to be pressed into the wire 4 by independently grooved sub-roller 25a and the sub-roller group 22a and the other sub-roller group 22a. The spring 25c, the support member 25d, the pressure sensor 25e, and the pressure stage 25f constitute a pressure control unit 25g. In this case, the predetermined pressure value according to the detected value of the deflection amount of each wire 4 detected by the deflection amount sensor 24 reduces the wire tension on the wire supply side, and the deflection amount of the wire 4 is recovered from the wire supply side. It is set to be held constant across the sides.

  Each grooved sub-roller 25a of a plurality (five here) of sub-roller groups applies wire tension in the first to fifth stages from the wire recovery side (old line side) to the wire supply side (new line side). Of the wire tension stretched between the plurality of grooved rollers 2 and 3, the wire recovery side wire tension is increased and the wire supply side wire tension is decreased. ing.

  That is, the sub-roller control unit of the tension control unit 25 monitors the detected value of the deflection amount of each wire 4 detected by the deflection amount sensor 24 (load cell; not shown here) and each monitored wire 4. The pressure stage 25f that pressurizes the wire 4 so that the wire tension on the wire supply side is kept constant from the wire supply side to the wire collection side by reducing the wire tension on the wire supply side in accordance with the detected value of the amount of bending of the wire. The wire tension on the wire collection side is maximized, and the tension is held in a state where the tension is gradually reduced for each of a plurality of wires from the wire collection side to the wire supply side. A tension monitoring unit (not shown) may be provided inside the pressurization stage 25f constituting the pressurization control unit 25g.

  In the above case, the tension control means 25 applies a tension higher than the tensile strength to the wire 4 so that the wire 4 is broken, or the winding force of the wire 4 around the grooved rollers 2 and 3 is weakened. The tension | tensile_strength of the wire 4 is set so that a cutting precision may not fall or the wire 4 may remove | deviate from an outer periphery groove | channel and cause a cutting defect. The tension of the wire 4 is set based on the breaking strength (tensile strength) of the wire 4.

  With the above configuration, first, all the grooved sub-rollers 25a are brought into contact with the wire row at the old line side tension value, and cutting of the workpiece 7 is started under a predetermined cutting condition.

  Next, the amount of bending of the wire 4 in the cutting region of the workpiece 7 detected by the amount of bending sensor 24 corresponding to the tension control unit 25 is monitored by the tension monitoring unit in the pressure control unit 25g of the tension control unit 25. . In accordance with the monitored detected value of the deflection amount of each wire 4, the wire tension on the wire supply side is reduced, and the deflection amount of the wire 4 is held constant from the wire supply side to the wire recovery side. The pressure stage 25f presses the grooved sub-roller 25a so as to push it into the wire 4 side.

  By repeating this, the wire tension on the wire supply side is maximized, and the tension is held in a state where the tension is gradually reduced for each of a plurality of wires from the wire recovery side to the wire supply side. The tension is reduced and the amount of bending of the wire 4 is kept constant from the wire supply side to the wire recovery side.

  Therefore, according to the third embodiment, the cutting wire 4 wound around the outer peripheral grooves of the plurality of (here, two) grooved rollers 2 and 3 arranged at a predetermined interval is caused to travel so that the wire 4 In the wire saw device 1B that cuts the workpieces 7 in a plurality of rows, among the wire tensions stretched between the grooved rollers 2 and 3, the wire tension on the wire recovery side is increased and the wire tension on the wire supply side is decreased. Control means 25 is provided. That is, the tension control means 25 maximizes the wire tension on the wire collection side and holds the tension in a state where the tension is continuously reduced for each wire 4 from the wire collection side to the wire supply side. In this case, a bend amount sensor 24 as a bend amount detecting means for detecting the bend amount of the wire 4 is provided between the grooved rollers 2 and 3, and the tension control means 25 has a bend amount of the wire 4 on the wire supply side. A pressurization control unit 25g that pressurizes the wire 4 according to the amount of deflection detected by the amount-of-deflection sensor 24 so as to be held constant from the wire collection side to the wire collection side is provided.

  The workpiece cutting method according to the third embodiment includes a wire tension setting step of automatically setting the wire tension of the wire 4 stretched between the grooved rollers 2 and 3, and an actual workpiece using the set wire tension. 7 (here, a semiconductor ingot). This wire tension setting step reduces the wire tension on the wire supply side based on the displacement of the wire deflection amount detected during actual work cutting, and the wire deflection amount is constant from the wire supply side to the wire recovery side. The tension control means 25 automatically controls the wire tension so that the wire tension is set.

  Thus, there is no need to adjust the wire tension by performing trial cutting, and the wire tension on the wire supply side (new line side) is directly reduced to reduce the bending amount of the wire 4 on the wire supply side (new line side). From the wire collection side (old wire side) to keep the wire cutting risk low, and the workpiece cutting ability is uniform on the wire supply side (new line side) and wire collection side (old line side) Thus, variation in the cutting thickness of each wafer can be reduced.

  In the third embodiment, instead of the deflection amount sensor 24 serving as a deflection amount detecting unit for detecting the deflection amount of each wire 4 and the tension control units 16 and 22 of the first embodiment, left and right along the wire 4 are used. Although the case where the tension control means 25 for controlling the tension of the wire 4 based on the deflection amount of each wire 4 detected by the deflection amount sensor 24 is provided has been described, the present invention is not limited to this. The deflection amount sensor 24 serving as a deflection amount detecting unit that detects the amount of deflection 4 and the tension control unit 16 or / and 22 of the first embodiment may be used. Also in this case, a sub-roller control unit similar to the sub-roller control unit of the tension control means 25 is necessary. This sub-roller control unit includes tension monitoring means (load cell; not shown here) for monitoring the detected value of the deflection amount of each wire 4 detected by the deflection amount sensor 24, and the detected detected value of the deflection amount of each wire 4. And a pressure stage 25f for applying pressure so that the wire tension on the wire supply side is reduced and the amount of bending of the wire 4 is kept constant from the wire supply side to the wire recovery side. The wire tension on the recovery side is maximized, and the tension is maintained in a state where the tension is gradually reduced for each of a plurality of wires from the wire recovery side to the wire supply side.

  In short, the tension control means 25 for controlling the tension of the wire 4 according to the deflection amount of the wire 4 using the deflection amount sensor 24 is not limited to the configuration of the third embodiment, but at two left and right locations along the wire 4. In addition to the connected sub-roller and the non-connected sub-roller of the first embodiment to be pressed, the present invention can be applied to all the sub-roller pressing configurations described in the first embodiment such as the pressing member 191 and the groove-free sub roller or the groove-less sub roller group of FIG. it can.

  In the third embodiment, the deflection amount sensor 21 is used and the deflection amount sensor 24 is used separately from the case where the workpiece feed amount is controlled according to the deflection amount of the wire 4. Although the case where the sub-roller pressing amount is adjusted using the tension control means 25 that controls the tension 4 is described, the present invention is not limited to this, and the deflection amount sensor 21 is used to control the workpiece feed amount according to the deflection amount of the wire 4. In addition to this, the sub-roller pressing amount may be adjusted by using the deflection amount sensor 24 and using the tension control means 25 that controls the tension of the wire 4 according to the deflection amount of the wire 4. The deflection amount sensor 24 may be separate from the deflection amount sensor 21, or the deflection amount sensor 24 may also serve as the deflection amount sensor 21.

  In the third embodiment, the grooved sub-rollers 161a, 161b, 161c, 161d, 161e, the grooved sub-rollers 162a, 162b, 162c, 162d, 162e, the sub-roller groups 22a-22f, the sub-roller group 23a, and the grooved sub-roller 25a are grooved. However, the present invention is not limited to this, and may be a grooveless sub-roller or a grooveless sub-roller group.

  In the third embodiment, there is no need to adjust the wire tension by performing the trial cutting by providing the pressure control unit 25g that pressurizes the wire 4 according to the amount of deflection detected by the amount of deflection sensor 24. However, in the first embodiment, it is necessary to adjust the wire tension by performing trial cutting.

  In addition, as mentioned above, although this invention has been illustrated using preferable Embodiment 1-3 of this invention, this invention should not be limited and limited to this Embodiment 1-3. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments 1 to 3 of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention relates to a wire saw device for cutting a workpiece with a cutting wire by running a cutting wire passed through the outer periphery of a plurality of grooved rollers arranged at predetermined intervals, a workpiece cutting method using the same, and a wafer In the field of manufacturing methods, wire tension is reduced from the wire supply side (new line side) to the wire recovery side (old line side) by reducing the wire tension on the wire supply side (new line side) By doing so, it is possible to suppress the risk of wire breakage and to make the workpiece cutting ability uniform on the wire supply side (new line side) and the wire recovery side (old line side), and to reduce variations in cutting thickness.

1, 1A, 1B Wire saw device 2, 3 Grooved roller 4 Wire 5 Supply reel (new wire bobbin)
6 Collection reel (old line bobbin)
7 Workpiece (semiconductor ingot)
8, 9, 11, 12 Guide roller 10, 13 Dancer roller 14, 15 Traverser 16, 161A, 161B, 162 Tension control means 161a, 161b, 161c, 161d, 161e Grooved sub-roller 161f Shaft member 161g Spring 161h Support member 162a, 162b , 162c, 162d, 162e Grooved sub-roller 162f Shaft member 162g Spring 162h Support member 17 Fixed part 18 Work feed mechanism 19 Tension control means 191 Pressing member 192 Holding member 193 Control part 20 Work fluid supply part 21 Deflection amount sensor 22, 23 Tension Control means 22a-22f Sub roller group 22g Shaft member 22h Energizing member 23a Sub roller group 23b Shaft member 23c Spring 23d Support member 24 Deflection amount sensor 25 Tension control means 25a Grooved sub-roller 25b Shaft member 25c Spring 25d Support member 25e Pressure sensor 25f Pressure stage 25g Pressure controller A Wire recovery side (old wire side)
B Wire supply side (new line side)
R1-R6 Groove sub-roller diameter

Claims (19)

In a wire saw device that travels a cutting wire wound around an outer peripheral groove of a plurality of grooved rollers arranged at a predetermined interval and cuts a workpiece by a plurality of rows of the wire,
A wire saw device having tension control means for increasing the wire tension on the wire recovery side and decreasing the wire tension on the wire supply side among the wire tensions stretched between the plurality of grooved rollers.   The tension control means holds the tension in a state where the wire tension on the wire collection side is maximized and the tension is gradually reduced for each one or a plurality of wires from the wire collection side to the wire supply side. Item 10. A wire saw device according to Item 1.   The tension control means reduces the wire tension on the wire supply side compared to the wire tension on the wire collection side and makes the amount of bending of the wire constant from the wire supply side to the wire collection side, or The wire saw device according to claim 1, wherein variation in the amount of bending of the wire is reduced from the wire supply side to the wire collection side.   The wire saw device according to claim 1 or 2, wherein a wire row surface for cutting the workpiece and a wire row surface with which the tension control means abuts are different wire row surfaces.   The wire saw device according to claim 1 or 2, wherein one or a plurality of the tension control means are provided, and the tension is controlled to a plurality of stages corresponding to the number of wires in the plurality of rows of the wires in two or more stages.   The wire saw device according to claim 1, wherein the tension control means sets the wire tension in a plurality of stages from the wire recovery side to the wire supply side.   The tension control means includes a plurality of sub-roller groups that are in contact with the wires, a shaft member that rotatably supports the plurality of sub-roller groups, a support member that supports the sub-roller group, and the sub-roller group that is fixed to the wires with a constant pressure. The wire saw device according to claim 6, wherein the wire saw device includes one or a plurality of urging members that urge each of the plurality of sub-rollers, and collectively presses the plurality of sub roller groups against each of the wires.   The wire saw device according to claim 7, wherein the diameter of the sub-roller is gradually reduced for each sub-roller group or each sub-roller of the sub-roller group from the wire collection side to the wire supply side.   The tension control means includes a sub-roller group that contacts each of the wires, a shaft member that rotatably supports the sub-roller group, a support member that supports the sub-roller group, and a sub-roller group that is attached to each of the wires with a constant pressure. The wire saw device according to claim 6, wherein the wire saw device includes a plurality of sets of biasing members for biasing, and each of the plurality of sets of sub-rollers is independently pressed against each of the wires.   10. The wire saw according to claim 9, wherein a pushing force or a pushing amount of the sub roller group to each of the wires is gradually reduced for each sub roller group from the wire collection side to the wire supply side. apparatus.   The wire saw device according to claim 7 or 9, wherein the wire tension device is configured to decrease the wire tension step by step for each of the sub-roller groups from the wire recovery side toward the wire supply side.   The wire saw device according to claim 7, wherein the wire tension device is configured to gradually reduce the wire tension for each sub-roller of the sub-roller group from the wire collection side toward the wire supply side.   Bending amount detection means for detecting the bending amount of the wire is provided between the grooved rollers, and the tension control means holds the bending amount of the wire constant from the wire supply side to the wire collection side. Alternatively, pressurization that pressurizes each of the wires in accordance with the amount of deflection detected by the amount-of-deflection detecting means so as to reduce variation in the amount of deflection of the wire from the wire supply side to the wire collection side. The wire saw device according to claim 6, wherein a control unit is provided. A workpiece cutting method using the wire saw device according to claim 1,
A wire tension setting step for setting the wire tension of the wire stretched between the grooved rollers by cutting the test workpiece, and a workpiece cutting step for cutting the actual workpiece using the set wire tension. Work cutting method.   15. The workpiece cutting method according to claim 14, wherein in the wire tension setting step, the wire tension is set by operating the tension control unit based on a displacement of the wire deflection amount detected during the cutting of the test workpiece. By controlling the wire tension on the wire supply side as compared with the wire tension on the wire recovery side, so that the wire deflection amount is kept constant from the wire supply side to the wire recovery side. Or the work cutting method which adjusts this wire tension and sets this wire tension so that variation in the amount of wire deflection may be reduced from the wire supply side to the wire collection side. A workpiece cutting method using the wire saw device according to claim 13,
A workpiece cutting method comprising: a wire tension setting step for automatically setting a wire tension of a wire stretched between the grooved rollers; and a workpiece cutting step for cutting an actual workpiece using the set wire tension. .   17. The work cutting method according to claim 16, wherein the wire tension setting step sets the wire tension on the wire supply side based on a displacement of a wire deflection amount detected during cutting of the actual work. Compared to the wire tension on the recovery side, the wire deflection amount is held constant from the wire supply side to the wire recovery side, or variation in the wire deflection amount is reduced from the wire supply side to the wire. A work cutting method in which the tension control means automatically controls the wire tension to set the wire tension so as to reduce it over the collection side.   The work cutting method according to claim 14 or 17, wherein the work cutting step controls a work feed amount of a work feed mechanism in accordance with the wire deflection amount.   19. The method of manufacturing a wafer according to claim 14, wherein the workpiece is a semiconductor ingot, and the semiconductor ingot is cut into a plurality of wafers by a wire row of the wire saw device.