FIELD OF THE INVENTION

[0001] Embodiments of the present invention relate to a wire saw device, a wire saw device, use of a wire saw device and a method for operating a wire saw device. More particularly, they relate to a wire saw device with improved wire transport direction, and a wire saw device for cutting or sawing hard materials such as blocks of silicon or quartz, e.g., for cutting silicon wafers, for a squarer, for a cropper, or the like.

BACKGROUND OF THE INVENTION

[0002] Wire saw devices exist for cutting blocks or bricks, thin slices, e.g., semiconductor wafers, from a piece of hard material such as silicon. In such devices, a stretched wire is fed from a spool and is both guided and tensioned by pulleys for guiding the wire in the cutting area. The wire that is used for sawing is generally provided with an abrasive material. As one option, the abrasive material can be provided as slurry. This may be done shortly before the wire touches the material to be cut. Thereby, the abrasive is carried to the cutting position by the wire for cutting the material. As another option, the abrasive can be provided on the wire with a coating. For example, diamond particles can be provided on a metal wire, e.g., with a coating, wherein the diamond particles are imbedded in the coating of the wire. Thereby, the abrasive is firmly connected with the wire.

[0003] Generally, there is a desire to increase the cutting speed for improving the throughput of wire saw devices. The maximum speed for moving the piece through the web, and also the maximum effective cutting area within a given amount of time is limited by several factors including wire speed, hardness of the material to be sawed, disturbing influences, desired precision, and the like. Yet, the yield of the cutting is also an important factor for defining the throughput. Thereby, the yield can be reduced if a few percent of the final workpieces are not within the specified ranges of precision. This can be, for example, the thickness of a wafer or the thickness variation within a wafer.

[0004] Generally, the yield of wire saw devices is already at a sophisticated level. However, there is a desire for a further improvement, particularly if the material to be cut is expensive.

SUMMARY

[0005] In view of the above, a wire saw device according to independent claim 1, a method of building a wire web according to independent claim 10, and a method of operating a wire saw device according to claim 12 are provided. Further advantages, features, aspects, and details are apparent from the dependent claims, the description, and drawings.

[0006] According to one embodiment, a wire saw device for sawing a hard material is provided. The device includes an inlet spool for providing wire towards the wire web, the wire web having an inlet side and an outlet side, a main frame of the wire saw device, a set of wire guides for building the wire web, wherein the set of wire guides is connected to the main frame more rigidly at a connection side than at an opposing side or wherein a connections of the wire guides at the connection side is configured for higher loads than at the opposing side, and a pulley arrangement configured for guiding the wire from the spool to the inlet side of the wire web, wherein the inlet side is closer to the side opposing the connection side than to the connection side.

[0007] According to another embodiment, a method of building a wire web in a wire saw device is provided. The method includes: guiding the wire from a inlet spool over a first pulley arrangement to an inlet side of the wire web, guiding the wire over a set of wire guides for forming the wire web to extend from the inlet side of the wire web to the outlet side of the wire web, wherein the set of wire guides is connected to the main frame at a connection side more rigidly than at an opposing side or wherein a connections of the wire guides at the connection side is configured for higher loads than at the opposing side, and guiding the wire from the outlet side of the wire web over a second pulley arrangement to a take-up spool.

[0008] According to a further embodiment, a method of operating a wire saw device having a wire forming a wire web is provided. The method includes rotating a set of wire guides such that the web is guided in axial rotation direction towards a connection side at which the set of wire guides is connected to the main frame more rigidly than at an opposing side or towards a connection of the set of wire guides at the connection side which is configured for higher loads as compared to the opposing side, and building a wire web. Thereby, building the wire web includes: guiding the wire from a inlet spool over a first pulley arrangement to an inlet side of the wire web, guiding the wire over a set of wire guides for forming the wire web to extend from the inlet side of the wire web to the outlet side of the wire web, wherein the set of wire guides is connected to the main frame at a connection side more rigidly than at an opposing side or wherein a connections of the wire guides at the connection side is configured for higher loads than at the opposing side, and guiding the wire from the outlet side of the wire web over a second pulley arrangement to a take-up spool.

[0009] According to a yet further embodiment, a wire saw device for sawing a hard material is provided. The device includes an inlet spool for providing wire towards the wire web, the wire web having an inlet side and an outlet side, a main frame of the wire saw device, a set of wire guides for building the wire web, at least one motor for driving at least one wire guide, wherein the set of wire guides is connected to the main frame at a connection side facing the motor, and a pulley arrangement configured for guiding the wire from the spool to the inlet side of the wire web, wherein the inlet side is closer to the side opposing the connection side than to the connection side.

[0010] Embodiments are also directed at apparatuses for carrying out the disclosed methods and including apparatus parts for performing each described method step. These method steps may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two, or in any other manner. Furthermore, embodiments according to the invention are also directed at methods by which the described apparatus operates. It includes method steps for carrying out every function of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the invention and are described in the following: FIG. 1 shows a schematic view of a wire saw device according to embodiments described herein;

FIG. 2 shows a schematic view of a yet further wire saw device according to embodiments described herein;

FIG. 3 shows a schematic view of wire guide cylinders and a wire web built thereon, according to embodiments described herein;

FIG. 4 shows a schematic perspective view of wire guide cylinders and a wire web built thereon according to embodiments described herein;

FIG. 5 shows a schematic view of a wire guide cylinder and illustrates one of several factors for the improved wire saw device according to embodiments described herein;

FIG. 6 shows a schematic view of a wire guide cylinder and illustrates another one of several factors for the improved wire saw device according to embodiments described herein;

FIG. 7 shows a schematic view of a wire guide cylinder and a workpiece support and illustrates a yet further factor of several factors for the improved wire saw device according to embodiments described herein; and

FIG. 8 illustrates a method of building a wire web and a method of operating a wire saw device according to embodiments described herein.

DETAILED DESCRIPTION OF THE INVENTION

[0012] Reference will now be made in detail to the various embodiments of the invention, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the invention and is not meant as a limitation of the invention. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations. [0013] Furthermore, in the following description a wire management unit will be understood as a device handling the supply of wire to a cutting area or working area of a wire saw device, such as a cropping wire saw device, a squaring wire saw device, or a wafering wire saw device. Typically, the wire saw includes a wire guide for transporting and guiding the wire in a wire moving direction, while the wire management unit provides control of the wire tension. Furthermore, the wire provided by the wire management unit forms a wire web in the cutting area. Often, a wire web will be considered as the web formed by a single wire management unit. It should be understood that a wire web may contain more than one working area portion, which is defined as an area in which a sawing process is performed. Thus, according to some embodiments described herein, a wire web can have multiple areas that are formed each by a wire from different wire management units.

[0014] For modern wire saw devices like cropping wire saw devices, squaring wire saw devices, or wafering wire saw devices, there is the desire to cut a hard material, such as semiconductor material, for example, silicon, quartz, or the like, at high speeds. The wire speed, that is, the speed of the wire moving through the wire saw device, the wire management unit and the material to be sawed, respectively, can be, for example, 10 m/s or higher. Typically, the wire speed can be in a range of 15 to 20 m/s. However, higher wire speeds of 25 m/s or 30 m/s, or even 40 m/s or higher can also be desirable and could be realized under certain conditions.

[0015] For unwinding and winding the wire at the desired wire speed, the spool rotates with a rotation speed of up to several thousand rotations per minute. For example, 1000 to 2000 rpm can be provided for unwinding and winding the wire.

[0016] FIG. 1 shows a wire saw device 100. As can be seen from the pattern of the wire 10 forming the wire web 111 in the wire web compartment 110, the example shown in FIG. 1 illustrates a wafering wire saw device, sometimes called a wire saw. The wire web is formed in the wire web compartment 110. Further, a housing portion, which houses further components and equipment of the wire saw device 100 is provided. For example, a wire handling device compartment 212 and an electrical cabinet can be provided. Within the further housing portion, tanks, as well as respective pumps, can also be provided.

[0017] According to some embodiments, which can be combined with other embodiments described herein, a first tank can be used for unused cooling fluid, e.g., in the case where the wire saw device is operated with diamond wire, or can be used, e.g., for unused (fresh) slurry, in the case where the wire saw device 100 is operated with a wire requiring additional abrasive. In those cases where cooling fluid or slurry is used, a portion of the used consumable fluid can be recycled and re-used if it is reinserted into the tank. Thus, according to different embodiments only a portion of the consumable fluid, all of the consumable fluid or none of the consumable fluid may be reused and, thus, be reinserted into the tank. According to different embodiments, as already described above, the consumable fluid can be cooling fluid or slurry. Generally, if slurry is used, the slurry also takes over the function of cooling the position at which the wire cuts the material.

[0018] In the wire handling compartment 212, two handling sections for delivering the wire 10 to the cutting area and receiving the wire from the cutting area, respectively, are provided. According to some embodiments, which can be combined with other embodiments described herein, the wire is provided on a spool 130 rotating around a spool axis. The wire is guided over a plurality of rollers 134 into the wire web compartment 110. Further pulleys 134 guide the wire 10 in the cutting area to form the wire web 111. In order to avoid unnecessary complexity, some of the further pulleys are not shown in FIG. 1. Further, the locations of shown pulleys can vary. After cutting, the wire is guided by a further pulley 134 towards the wire handling compartment 212, and is therein provided over pulleys 134 on the spool 132 rotating around the spool axes.

[0019] In the past, bi-directional sawing has been suggested for various reasons, e.g., to be able to re-use those types of wires which can be used for a plurality of cuts, such as diamond wires. According to embodiments described herein, a unidirectional sawing is also provided, wherein the wire 10 is guided in the cutting area, i.e., in the area of the wire web 111, in a reverse direction. Thereby, the inlet spool and, particularly, the pulley arrangement for guiding the wire towards the web from the inlet spool differs from a bi-directional sawing, as the wire from the inlet spool, which is different from the take-up spool for various reasons described below, is guided to a different position of the wire web for defining a starting point of the wire web.

[0020] Typically, the wire is guided from the wire handling compartment to the wire cutting area and back with a wire speed of 10 m/s or higher, typically in a range of 15 to 20 m/s, or even up to 25 m/s or 30 m/s. The material to be cut is positioned on a support. The support and the wire web provided by the wire guide cylinders 180 can be moved relative to each other such that cutting of the material can be conducted. According to one embodiment, the wire guide cylinders 180 remain in a fixed position and the support moves the material to be cut through the wire web while the wire is at a speed of about 10 m/s or higher. For easier understanding, in FIG. 1, this movement of the support would be perpendicular to the plane of the drawing. According to another embodiment, the wire guide cylinders 180 and, thus, the web 111 generated by wire 10 is moved relative to the support to cut the wire through the material. According to yet a further embodiment, both the support and the wire guide cylinders 180 can be both moved with respect to each other.

[0021] According to different embodiments, a wire saw device can be a cropper, a squarer, a wire saw, or a multiple wire saw. Thereby, a cropper is to be understood as a device which can be used to saw end pieces from bricks or blocks, which have been separated into bricks in a squarer. A squarer is a wire saw that generally saws the silicon ingot into squares of the desired size, such that a wire saw or a multiple wire saw can saw wafers from the bricks in a wafering process. The wire management unit herein is particularly useful for the wire saw device being a wafering wire saw device but not limited to a wafering wire saw device.

[0022] The above-described systems are particularly useful if thin wires are used. Accordingly, in embodiments which can be combined with other embodiments described herein, the wire handling sections and wire saw devices described herein are adapted for thin wires having a diameter below about 500 μιη, such as diameters between about 200 μιη and about 400 μιη, more particularly between about 200 μιη and about 300 μιη. However, in other cases embodiments may also have a wire diameter as low as, for example, 100 μιη, 80 μιη, or even thinner.

[0023] The wire saw device 100, which is shown in figure 1, includes a mainframe 140. For example, the mainframe can include the first portion 142 and a second portion 143. Generally, the mainframe can provide a stabilizing functionality and/or a plurality of components can be connected to the mainframe in order to provide these components with positions relative to each other. As shown in figure 1, the main bearings 172 are connected to the mainframe 140. The main bearings 172 are bearings for allowing rotation of the wire guides 180 around an axis of the wire guide cylinders. Further, a secondary frame 150 is provided and secondary bearings 174 are connected to the secondary frame 150. The secondary bearings 174 can also support the wire guides 180 during rotation thereof.

[0024] As indicated and implied in FIG. 1 by the size of the main bearings 172 and the secondary bearings 174, the side of the main bearings (the lower side of wire guide 180 in figure 1) have a more rigid connection and/or the connection being configured for higher loads as compared to the secondary bearings 174. Accordingly, the wire guides 180 have a connection side, at which the wire guides are connected to the mainframe 140 and have another side opposing that connection side, at which the wire guides can, for example, be connected to the secondary frame 150. According to embodiments described herein, the connection side provides a more rigid connection and/or a connection capable of taking higher loads as compared to the connection at the opposing side.

[0025] Even though the wire guides 180 and the wire web 111 formed on the wire guides could in isolation be regarded as a symmetric arrangement, there are a plurality of factors which introduce a kind of symmetry in the wire saw device. Accordingly, the wire web 111 cannot be practically considered as fully symmetric.

[0026] Accordingly, the inventors of the present invention found that there is a sawing direction for which an inlet at a particular side of the wire web, i.e., the upper side of the wire web 111 in figure 1 results in an improved yield. According to embodiments described herein, which can be combined with other embodiments, the sawing direction, i.e., a transport direction of the wire such that the wire is provided from the inlet spool 132 to the wire web where the wire guides 180 have a less rigid connection to the main frame 140 or where the connection to the main frame 140 is configured for lower loads as compared to the other side, results in a better yield.

[0027] Accordingly, as shown in figure 1, the inlet spool 130 guides the wire over that plurality of pulleys 134 to the wire web 111 at the side opposing the more rigid or the increased load connection to the mainframe, i.e., the upper side in figure 1. This is indicated by the arrows in figure 1 showing the preferred wire direction in the wire saw device 100 and is further indicated by reference numeral lOi illustrating the wire inlet. Accordingly, the wire outlet lOo is from the outlet side of the wire web 111, which is closer to the more rigid connection or the connection configured for higher loads. As shown in figure 1 this can be the side of the main bearing 172.

[0028] Thereby, it has to be considered that the wire with reference numeral lOi is a fresh wire, whereas the wire indicated by reference 10ο is used wire. The inventors have found that providing that used wire at a side of the wire web 111 or at the side of the wire guides 180, respectively, having the more rigid connection or the connection configured for a higher load results in an improved yield of the wire saw device 100. It is believed that this is due to the fact that having the used wire which will have a few microns reduction in diameter at a more rigid side of the wire guides is less harmful to the yield of the sawing process.

[0029] Figure 2 shows another embodiment of a wire saw device 200 having in principle the same features as the embodiments described with respect to figure 1 except for two changes, which can be realized in combination or independently of each other.

[0030] First, there are two wire management units having inlet spools 130 and take-up spools 132, wherein each wire management units provides the wire to the wire web 211. The wire web 211 includes two portions, wherein each portion is provided by a separate wire. Each separate wire is fed from an inlet spool 130 to a corresponding outlets were 132. As described above, that inlet of the wire 10 to the wire web 211 is for each wire management units at the side of the wire guides 180 which is opposing to the side having the more rigid connection or a connection which is configured for higher loads, i.e., the main bearing 172.

[0031] Second, the inlet spool 130 is closer to the inlet position of the wire into the wire web 211. The difference of the fist distance of the inlet spool to the inlet position at the wire web and the second distance of the take-up spool 132 to the position of the outlet from the wire web is smaller as compared to the respective distances in figure 1. Thereby, the distances from the inlet spool to the inlet side of the wire web and the take up spool to the outlet side of the wire web are made more equal, which can be considered beneficial for wire management and can further improve the symmetry of the configuration.

[0032] In the following, yet further embodiments are described, whose elements can be combined with any elements of other embodiments described herein. Within the following description, only those elements will be described, which deviate from those of previous or other embodiments described herein. It is to be understood that components, aspects, and details described with respect to other embodiments can be applied to those embodiments which do not describe all components, aspects, or details as well.

[0033] Figures 1 and 2 further show a first portion of a support table for supporting workpieces such that they can be moved relative to the web. According to alternative embodiments, the wire web can be moved relative to the support table, or both the support table and the wire web can be moved relative to each other. Two further schematic views are illustrated in figures 3 and 4. [0034] Figure 4 shows the support table 160 and beams 320 connected thereto. The workpieces 322, which are connected to the beams 320, can be moved along directions, which are indicated by reference numerals 460, by movement of the support table 160. As shown in figure 4, the wire guides 180 are provided to build an upper portion of the wire web 310 and the lower portion of the wire web 310. Thereby, exemplarily, four workpieces 322 can be sawed by the wire saw device. In figure 3, the preferred wire direction is indicated by arrow 310 such that the wire has an inlet portion lOi and an outlet portion 10ο. As described above, that inlet portion is on the side opposing the main bearings 172. Thus, as shown in figure 4, the inlet port 130 provides the wire to the inlet side of the wire web 310 and the wire is provided from the outlet side of the wire web 310 to the take-up spool 132.

[0035] According to further embodiments, which can be combined with other embodiments described herein, the wire saw device can further include a fluid pipe 420, which is configured for providing slurry or a cooling fluid to that wire positions of the while web 310. The fluid pipe 420 typically has a plurality of outlet nozzles for spraying the fluid, such as slurry or the cooling fluid, onto the wire web. Further, the fluid pipe 420 has a fluid inlet, which is indicated by arrow 422 in figure 4. According to typical embodiments, which can be combined with other embodiments described herein, the fluid inlet is provided at the side of the wire outlet, where the used wire exits the wire web. This is typically the side with the more rigid connection of the wire guides 180, the side with the connection being configured for higher loads, and/or at the side having the main bearing. Even though a sufficiently high fluid pressure in the fluid pipe 420 can result in an almost equal fluid distribution on the wire web in a direction parallel to the rotation axis of the wire guides 180, there is still some asymmetry, which results in a preferred wire inlet positioned of the wire into the wire web, as described above.

[0036] Further factors, which provide an asymmetry in the wire web, and, thus, the preferred wire direction within the wire web along and rotation axis of the wire guides 180 are illustrated in figures 5 and 6. These figures show a wire guide 180 being supported by a main bearing 172 and secondary bearing 174, the wire guides 180 have an outer portion rotating around the rotation axis 581 around a central portion 580. As shown in figure 5, the wire guides have a plurality of grooves for having that wire being provided within the grooves for forming the web, respectively, whereby the wire web is formed. According to typical embodiments, the grooves can be formed as follows. The grooves shown in figure 5 have a first slope 581 and a second slope 584. Between the slopes there are flat portions in the valley portions of the grooves and between two grooves. According to different embodiments, the grooves can also be formed without flat portions in either one or both of these positions. 582 and 583. During operation, the wires are positioned at the flat portions 583. According to yet further embodiments, the grooves can also have first and second slopes without flat portions. Yet, according to further embodiments, the grooves have a first slope 581 steeper than a second slope 584.

[0037] According to some embodiments, which can be combined with other embodiments described herein, the wire inlet and the wire outlet of the wire web, which are indicated by arrow 310 in figure 5, is such that the wire inlet is towards that slope 584, which is less steep. Accordingly, asymmetry in the slopes, which form the grooves in the wire guide 185, is provided. The resulting preferred wire transportation direction along the rotation axis of the wire guides 180 can result in better yield than an opposing wire guide direction.

[0038] Even for embodiments, where the first slope 581 and the second slope 584 are manufactured to be theoretically similar, the manufacturing process of the grooves, i.e., the grooving, will generally result in some asymmetry. Further, the grooves will be used up during the sawing process and can result in asymmetry due to the use of the wire saw device. Thus, even for desired symmetric grooves, an asymmetry will generally be generated and will, thus, result in a preferred wire transportation direction.

[0039] A further factor, which results from a deviation of perfect conditions, is shown in figure 6. Arrow 610 illustrates a tension varies in the wire during the sawing process and within the wire web. The wire, which is introduced on an inlet side of the wire web (see arrow 310), i.e., the right-hand side in figure 6, saws a plurality of portions of the workpiece while being transported in figure 5 from the right-hand side to the left-hand side. The sawing process, that is, the movement of the wire through the workpiece to be sawed, results in a change in tension on the wire. Accordingly, the tension of the wire on the wire guide 180 at a side towards the secondary bearing 174 will be different from the tension of the wire on the wire guide 180 at a position towards that main bearing 172. This is another factor, which introduces an asymmetry, as compared to perfect practical conditions and results in a preferred wire inlet position on the wire guide 180, the preferred position being towards the secondary bearing 174, at a side having a less rigid connection, and/or at a side with a connection being configured for smaller loads than the opposing side. [0040] Another factor, which can according to yet further additional or alternative embodiments be combined with the embodiments described herein, is illustrated with respect to figure 7. The wire guide 180 is provided and supported by the main bearing 172. As shown in figure 7, according to some embodiments, which can be combined with other embodiments described herein, the secondary bearing is not required and the more rigid connection and/or the connection configured for high loads is the connection at the main bearing side. The wire guide 180 is configured for rotation around the axis 581. An outer portion of the wire guide rotates around an inner portion 580. The wire inlet and wire outlet with respect to the wire guide and, thus, the wire web is illustrated by arrow 310. Figured 7 further shows a beam 320 and the workpiece 322, which is connected thereto. Typically, the workpiece 322, for example a multi-crystalline silicone block has a side with a harder material and a side with softer material. This is indicated by arrow 720. Within figure 7, the hardness of the material increases along arrow 720. Accordingly, the harder side of the workpiece 322 is at the side of the workpiece, which is in Fig. 7 facing the main bearing.

[0041] The increase of hardness of the workpiece for wavering is generally generated by the fact that the workpieces 322 for wavering our sawed from a block of multi-crystalline silicone, or the like. During manufacturing of block, the upper side of the block will generally have a harder material structure than the bottom side of the block. Thus, after squaring of the block, that side of the sawed bar corresponding to the upper side of the block will have a harder material.

[0042] As described above, during sawing of the workpiece 322, which is shown in figure 7, the harder side can be provided to be oriented towards the connection side of the wire guide 180. This is counter-intuitive, because it should be assumed that the harder side should be sawed with the fresh wire which is provided at the inlet position, i.e. the right-hand side in figure 7. However, the overall yield can be improved by providing the harder side of the material at the position, where the wire guide 180 has the more rigid connection to the main frame of the wire saw advice and/or the connection of the wire guide 180 to the mainframe of the wire saw advice is configured for higher loads as compared to an opposing side.

[0043] The above described embodiments, which have mainly be described with respect to wire saw devices also result in different and documents, which are provided by methods. For example figure 8 illustrates a method of building a wire web in the wire saw advice and a method of operating a wire saw device. In step 802, the wire, which is provided on an inlet spool is guided from the inlet pool over a pulley arrangement to the inlet side of the wire web, i.e. an axial inlet position of the wire onto wire guides. In step 804, the wire is provided around the wire guides for forming the wire web. According to typical embodiments, the wire can be guided around four wire guides, which are provided in a rectangular configuration as shown in figure 4. Thereby an upper portion of the wire web and lower portion of the wire web are provided and workpieces can be sawed in each of these portions. As described above, according to embodiments described herein, the inlet side or inlet position of the wire into the wire web or on to the wire guide is opposing a side having a more rigid connection or a side opposing the connection being configured for higher loads. In step 806, the wire is guided from the outlet side of the wire web over a second pulley arrangement to a take-up spool. Accordingly, steps 802, 804, and 806 provide a method for building a wild web with the preferred orientation of wire transportation in the wire web according to embodiments described herein.

[0044] The method of operating a wire sought advice according to embodiments described herein can further include step 808, wherein the wire guides are rotated such that the wire is guided along the actual rotation direction towards the connection side.

[0045] In light of the above, a plurality of embodiments has been described. According to one embodiment, a wire saw device for sawing a hard material is provided. The device includes an inlet spool for providing wire towards the wire web, the wire web having an inlet side and an outlet side, a main frame of the wire saw device, a set of wire guides for building the wire web, wherein the set of wire guides is connected to the main frame more rigidly at a connection side than at an opposing side or wherein a connections of the wire guides at the connection side is configured for higher loads than at the opposing side, and a pulley arrangement configured for guiding the wire from the spool to the inlet side of the wire web, wherein the inlet side is closer to the side opposing the connection side than to the connection side. According to another embodiment, a wire saw device for sawing a hard material is provided. The device includes an inlet spool for providing wire towards the wire web, the wire web having an inlet side and an outlet side, a main frame of the wire saw device, a set of wire guides for building the wire web, at least one motor for driving at least one wire guide, wherein the set of wire guides is connected to the main frame at a connection side facing the motor, and a pulley arrangement configured for guiding the wire from the spool to the inlet side of the wire web, wherein the inlet side is closer to the side opposing the connection side than to the connection side. According to further implementations of the one embodiment or the another embodiment, one or more of the following features can additionally or alternatively be selected from the group consisting of: the device can further include a take-up spool, and a further pulley arrangement configured for guiding the wire from the outlet side of the wire web to the take-up spool, wherein the outlet side is closer to the connection side than to the side opposing the connection side; the set of wire guides can be a set of wire guide cylinders having a main bearing for rotation around an axis of the cylinder at the connections side, and optionally a secondary bearing for rotation around an axis of the cylinder at the opposing side; the set of wire guides can include two wire guide cylinders or four wire guide cylinders; and the system can further include a secondary frame portion being less rigid than the main frame portion or being configured for lower loads than the main frame portion, and wherein the secondary bearing is connected to the secondary frame portion. According to yet further embodiments, which can be combined with other embodiments or implementations described herein, the inlet spool and the take-up spool can be different types of spools, particularly wherein the take-up spool can have a conical wire receiving portion; each of the set of wire guides can include a plurality of grooves for guiding the wire to form the wire web, and wherein each of the plurality of grooves includes a first slope being steeper than a second slope, and wherein the stepper slope is closer to the outlet side than to the inlet side; the device can further include at least one support table configured for supporting the hard material to be sawed, wherein the material has a harder side and a softer side opposing the hard side, wherein the support table is configured to support the table with the harder side closer to the connection side; and/or the device can further include a fluid pipe having a plurality of nozzle outlets and having a fluid inlet, wherein the fluid inlet is closer to the connections side than to the opposing side.

[0046] According to another embodiment, a method of building a wire web in a wire saw device is provided. The method includes: guiding the wire from a inlet spool over a first pulley arrangement to an inlet side of the wire web, guiding the wire over a set of wire guides for forming the wire web to extend from the inlet side of the wire web to the outlet side of the wire web, wherein the set of wire guides is connected to the main frame at a connection side more rigidly than at an opposing side or wherein a connections of the wire guides at the connection side is configured for higher loads than at the opposing side, and guiding the wire from the outlet side of the wire web over a second pulley arrangement to a take-up spool. Thereby, for example, the inlet spool and the take-up spool can be different types of spools, particularly wherein the take-up spool can have a conical wire receiving portion. [0047] According to a further embodiment, a method of operating a wire saw device having a wire forming a wire web is provided. The method includes rotating a set of wire guides such that the web is guided in axial rotation direction towards a connection side at which the set of wire guides is connected to the main frame more rigidly than at an opposing side or towards a connection of the set of wire guides at the connection side which is configured for higher loads as compared to the opposing side, and building a wire web. Thereby, building the wire web includes: guiding the wire from a inlet spool over a first pulley arrangement to an inlet side of the wire web, guiding the wire over a set of wire guides for forming the wire web to extend from the inlet side of the wire web to the outlet side of the wire web, wherein the set of wire guides is connected to the main frame at a connection side more rigidly than at an opposing side or wherein a connections of the wire guides at the connection side is configured for higher loads than at the opposing side, and guiding the wire from the outlet side of the wire web over a second pulley arrangement to a take-up spool. According to further alternative or additional modifications thereof, the method can further include providing a workpiece having a harder side and a less hard side such that the harder side of the workpieces faces the connections side and/or the rotating can be a unidirectional rotating.

[0048] According to the embodiments described herein, the yield of a wire saw device and of a sawing process with a wire saw device can further be improved by designing the wire saw device for an improved sawing direction, i.e. a first pulley arrangement guides the wire from the inlet spool to the desired wire web position described herein, and by operating the wire saw device accordingly. The improved yield also results in an improved throughput of the device.

[0049] While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.