KR20010021539A - Apparatus and method for slicing a workpiece utilizing a diamond impregnated wire - Google Patents

Abstract

The present invention provides that the workpiece (or ingot) is continuously or repeatedly rotated about its longitudinal axis as the diamond wire is driven perpendicular to the longitudinal axis of the workpiece or the diamond wire saw is repeatedly or continuously A device and method for thinly cutting a workpiece, in particular a polysilicon or single crystal silicon ingot, using a diamond containing wire saw that is rotated about a longitudinal axis. When relative movement is continuous, the wire proceeds from a position tangentially adjacent to the outer diameter "OD" of the ingot from a position tangential to the center or inner diameter "ID". In both cases, single-crystal silicon ingots of 300 to 400 mm and diamond wire cuts passing through the workpiece at the virtual contact of the cut instead of directly passing through the entire diameter of the workpiece are relatively small with minimal cutting losses and less extensive subsequent grinding operations. It can be quickly cut into thin wafers.

Description

APPARATUS AND METHOD FOR SLICING A WORKPIECE UTILIZING A DIAMOND IMPREGNATED WIRE}

Most of the current semiconductor and integrated circuit devices are fabricated on silicon substrates. The substrate itself is initially formed using raw polycrystalline silicon with randomly oriented crystallites. In this state, however, silicon does not exhibit the necessary electrical properties necessary for the manufacture of semiconductor devices. By heating the high purity polycrystalline silicon to a temperature of about 1400 degrees, monocrystalline silicon seeds are added to the melt and the single crystal ingots are pulled to have seeds of the same orientation. Ingots of 150 mm (6 inches) or 200 mm (8 inches) in diameter can be produced with current technology, but initially such silicon ingots had relatively small diameters of approximately 25.4 to 101.6 mm (1 to 4 inches). Recent advances in crystal growth technology have made it possible to produce ingots of 300 mm (12 inches) or 400 mm (16 inches) in diameter.

Once the ingot is fabricated, the ingot is cut to be serially processed into multiple die for discrete or integrated circuit semiconductor devices (ie, the "head" and "tail" portions of the ingot must be cut off). It must then be cut thinly into individual wafers. The main way to cut an ingot is to use a bandsaw with a relatively thin flexible blade. However, the large amount of flutter inherent in the band saw blade leaves a large amount of "kerf" loss and the saw blade of the cutting blade, which must be polished.

Currently, there are two main methods for cutting an ingot thinly into wafers: an ID hole saw and a slurry saw. The former is mainly used in the United States for thinly cutting single crystal silicon and is so named due to the fact that the cutting edge of the blade is adjacent in the centering hole and its inner diameter in order to reduce the flutter of the blade and the damage of the resulting crystal structure. Among the disadvantages of this technique, when the diameter of the silicon ingot is increased, the inner bore saw is three times larger than the ingot diameter so that the inner bore saw can always cut unnecessarily large points when the inner bore saw is inoperable. The disadvantage is that it must be large.

As mentioned above, a slurry saw is a technology that is also used in the United States but is mainly used in Pacific Rim countries. The slurry saw comprises a series of mandrels, which are driven through an ingot when a very long wire is rounded about the mandrel and then a silicon carbide or boron carbide slurry is loaded onto the wire. Wire breakage is an important issue and saw downtime can become important when wires need to be replaced. Also, when the ingot diameter is increased from 300 to 400 mm, drag of the wire through the ingot will reach a point where breakage is likely to be significant unless the wire gauge is increased due to significant "cutting" losses. Importantly, slurry saws can take considerable time when cutting through large diameter ingots.

In addition, as in the case of the inner bore saw technique, excessive "cutting" losses result in an additional increase in cost per wafer, resulting in a reduction in the amount of wafers that can be thinly cut from a given ingot. Moreover, the reduction of the score mark of the inner bore saw and the cutting amount of the slurry saw wires has to increase the length to smoothly and parallelize the surface of the wafer and to eliminate other surface marks and defects, resulting in expensive polishing operation costs. . In addition, such extensive polishing operations require a significant amount of silicon carbide and oil or aluminum oxide slurries, and their treatment causes well known environmental problems.

Laser Technology West, Limited, Colorado Springs, Colorado, a manufacturer and distributor of diamond-containing cutting wires and wire saws. Developed and manufactured. These wires comprise a high tensile strength steel core with an electrolytically deposited outer circumferential copper sheath uniformly embedded with very small diamonds (approximately 20 to 120 μm). Nickel overstrike in the superlock wire serves to better retain the cut diamond in the copper sheath. Techniques for cutting stationary workpieces using reverse diamond wires are currently one of the most commonly used in the laboratory, but are inherently unused in the manufacturing process due to too slow cutting speeds.

The present invention generally relates to the technical field of an apparatus and method for accurately sawing a workpiece into two or more parts. In particular, the present invention relates to apparatus and methods for cutting or thinly cutting crystalline ingots such as relatively large diameter polysilicon and single crystal silicon ingots with high precision, high speed and high efficiency.

The above and other features and objects of the present invention and methods for achieving the same will become more apparent and the present invention will be best understood with reference to the preferred embodiments and the following description taken in conjunction with the accompanying drawings.

1 is a simplified illustration of an apparatus for thinly cutting a workpiece, in particular a single crystal silicon ingot, by an exemplary method of the present invention.

FIG. 2 is a partial cut end front view in more detail than the apparatus of FIG. 1 in that the cutting wire is continuously or repeatedly rotated by a rotating collet fixture while the cutting wire is driven substantially tangentially with respect to the outer periphery of the cut in the ingot.

Figure 3 is a more detailed partial cut away of the apparatus of Figures 1 and 2 showing a connecting lead screw and a rotating collet rotating fixture for translationally repositioning the workpiece between cuts defining a plurality of wafers thinly cut from the ingot. End front view.

4A and 4B show different detailed isometric views of the device of FIGS. 2 and 3, further illustrating the internal relationship of the wire drive, the workpiece rotation or repetitive movement mechanism, and the wire propagation and workpiece reposition mechanism. to be.

Fig. 5 is a further detailed partial cutaway side view of an alternative embodiment of the present invention, for example using multiple cutting wires, in that the ingot is rotated by an end-mounted workpiece rotating mechanism fixed adjacent its end.

6A and 6B are simply plan views showing an apparatus for thinly cutting a workpiece, in particular a single crystal silicon ingot, by another exemplary method of the present invention in which the saw is rotated relative to the workpiece during the cutting operation.

Apparatus and method for cutting a workpiece thinly are disclosed, in particular the workpiece (or ingot) from which the diamond wire is driven perpendicular to the longitudinal axis of the workpiece to be adjacent to the outer diameter (OD) of the ingot (ID). Disclosed are polysilicon or single crystal silicon ingots using diamond-containing wire that rotates back and forth about its longitudinal axis continuously or repeatedly with respect to the diamond wire as it progresses toward. This relative movement between the wire and the workpiece in addition to the vertical wire movement is achieved by rotating the workpiece about its longitudinal axis or by rotating the sawtooth wire about the longitudinal axis of the workpiece during the cutting operation. This movement may be in the front-rear direction continuously or repeatedly through the arc. In this way, the diamond wire cuts through the workpiece at a point that is substantially tangential to the outer periphery of the cut instead of passing through the entire diameter of the workpiece. By using this technique, polysilicon or single crystal silicon ingots having a size of 300 to 400 mm or more can be relatively thinly cut into wafers with minimal cutting loss and less extensive subsequent polishing operations. This apparatus and method of the present invention allows for more wafers that can be thinly cut from a given ingot with reduced subsequent work indicating faster and significant cost savings.

In particular disclosed herein are methods of sectioning a substantially cylindrical crystalline workpiece. The method includes providing a wire having a plurality of cutting elements attached thereto and perpendicular to the longitudinal axis of the workpiece while rotating the workpiece about the longitudinal axis of the workpiece or rotating the wire about the longitudinal axis of the workpiece. Moving the wire, and advancing the wire from a first position adjacent the outer diameter of the workpiece to a second position adjacent the inner diameter or the center.

An apparatus for dividing a substantially cylindrical crystalline based workpiece is also disclosed. One embodiment of the apparatus includes a wire having a plurality of cutting elements attached and a wire drive mechanism for moving the wire perpendicularly to the longitudinal axis of the workpiece, and to the workpiece for rotating the workpiece about the longitudinal axis. And a combined workpiece rotating mechanism and a wire moving mechanism for positioning the wire from a first position adjacent the outer diameter of the workpiece to a second position adjacent the inner diameter or the center.

In a second embodiment, the wire drive mechanism is moved around the workpiece by the rotating mechanism while the workpiece remains stationary on the frame and the wire movement mechanism positions the wire from a first position adjacent the outer diameter to a second position adjacent the inner diameter. Similar to the first embodiment except that it is rotated. Rotation of the wire drive mechanism may be continuous and repeatable in one direction through a given arc. In the latter case, the angle of the arc may change depending on the depth of cut through the ingot. For example, at the beginning of the cut through the ingot, the arc can be quite small, only a few degrees, and then gradually increase as the cutting progresses. This repetitive movement of the wire drive mechanism can cause the wire to be cut to transversely guide the wire during cutting, effectively minimizing the effects created by surface unevenness on the ingot on cutting precision.

Referring to FIG. 1, a schematic diagram of a device 10 for thinly cutting a cylindrical workpiece such as polysilicon or single crystal silicon, gallium arsenide (GaAs) or other crystalline ingots is shown. Apparatus 10 is a suitable component, such as, for example, diamond-containing wires such as Superwire® or Superlock® series of cutting wires available from Laser Technology West, Limited, Colorado Springs, Colorado, USA. Cutting wire 12. Wire 12 is a method and apparatus 10 of the present invention for accurately and quickly cropping and sawing silicon ingots 14 into multiple wafers for continuous processing into discrete or integrated circuit devices. Used with

The device 10 has a wire drive mechanism 16 for reciprocating the wire 12 in a single direction or as indicated by an arrow, relative to the ingot 14. The wire drive mechanism 16 of the illustrated embodiment may include a capstan 18 for selectively winding and unwinding relative to the central pulley for transmitting reciprocating motion to the wire 12. Optionally, if one or more individual continuous loops of wire 12 are used in place of one straight length wire, the wire 12 is readily in one direction continuously without reversal, as described in more detail below. It may be moved. As shown, the wire 12 may be guided near the ingot 14 by a pair of pulleys 20 with the tensile force of the wire 12 properly maintained by the tension pulley 22.

The apparatus 10 further includes a workpiece rotating mechanism 24 for rotating the ingot about its longitudinal direction as the wire 12 is moved vertically relative to the ingot 14 in a single direction or in both directions as described above. do. The workpiece rotating mechanism 24 of the illustrated embodiment may include one or more rotating collet fixtures 26 that encircle the ingot in the circumferential direction along its longitudinal direction, as described in more detail below. The collet fixture, ie the ingot 14, may be rotated by multiple drive rollers 28 or functionally the same element. In alternative embodiments, ingot 14 may be secured to end-mounted workpiece rotating mechanism 24 in place of the embodiment shown in this figure.

In addition, the device 10 is equipped with a wire driving mechanism 30 mounted with a wire driving mechanism and shown in the first embodiment. The wire propagation mechanism 30 is disposed outward from the outer diameter (“OD”) of the ingot 14 so as to be completed in one cutting operation, and from the initial position 32 adjacent to the inner diameter (“ID”) of the ingot 14. It serves to advance the moving wire 12 toward an adjacent final position 34. At this inner diameter point, the movement of the wire propagation mechanism may be reversed to retract the wire back toward the initial position 32.

In this application where it is desirable to repeatedly cut or thinly cut through the ingot 14, the apparatus 10 may be thinly cut, for example, in a plurality of wafers, such that the wire 12 can be repeatedly cut along the length of the ingot. Workpiece repositioning mechanism 36 may be further provided such that ingot 14 may be indexed and translationally relocated. In the illustrated embodiment, the workpiece repositioning mechanism 36 is supported by a plurality of rollers 40 with respect to the wire 12, thereby programmable repositioning the workpiece rotating mechanism 24 and the ingot 14. It may also include an index driven lead screw 38. In alternative embodiments, the wire drive mechanism 16 and the wire propagation mechanism 30 may be repositioned relative to the fixed position workpiece rotation mechanism 24.

Referring to Figures 2, 3, 4A and 4B, there is shown in detail a particularly typical implementation of the apparatus 10 as previously shown and described with respect to Figure 1. For the apparatus 10 shown in these figures, the same structures described and shown above are denoted by the same reference numerals and the above description will be sufficient.

With particular reference to FIG. 2, it can be seen that the device 10 may include a base 42 that provides a pair of upwardly extending upright supports 44 to the work surface. One or more crossbeams 46 may extend between the distal ends of the upright support 44 as shown. Also shown is a wire tensioner 48 for properly maintaining the tension of the wire 12 for the wire drive mechanism 16. Wire tensioner 48 may include a spring or other suitable means to bias tension pulley 22 to keep wire 12 at proper tension during the sawing operation. Since the wire propagation mechanism 30 may include a microstepper feed drive 50 slidably supported by the upright support 44 and coupled with the driven linear actuator 52 and the corresponding idler linear actuator 54, the actuator Each of 52, 54 is associated with a corresponding one of the upright supports 44.

With particular reference to FIG. 3, the capstan 18 of the wire drive mechanism 16 may be used while the microstepper 58 is used to rotate one or both of the drive rollers 28 of the workpiece rotation mechanism 24. As shown, it may be driven by the drive motor 56. The microstepper 58 may be controlled to rotate the workpiece in one rotational direction or iteratively controlled to rotate the workpiece in one direction of a certain angle, and then rotate the workpiece again at a certain angle. Can be reversed. Preferably, the particular angle is as small as a few degrees at the beginning of the cut, and gradually increases as the cut progresses through the ingot beyond the 45 degree rotation angle. In this way, the wire saw ingots at the time of cutting while maintaining the advantages of the sidewall guides of the kerf during cutting to counteract lateral forces on the wire that may exist when surface defects on the outer cylindrical surface of the ingot occur during cutting. Effectively maintains a relatively constant tangential contact with respect to

In the illustrated embodiment, the drive roller 28 may have a plurality of longitudinally extending teeth for engaging the corresponding peripherally extending teeth of the collet fixture 26. The collet fixture 26 further adds a center clamp (not shown) so that the ingot 14 can be accurately centered within the collet fixture 26 so that the ingot 14 can rotate accurately about the longitudinal axis during operation of the device 10. It may also include.

As also shown, the device 10 includes a carriage supporting the ingot 14 and a workpiece rotating mechanism 24 coupled thereto, which is selectively moved along the workbench of the base 42 to the wire drive mechanism 16. It may further comprise a microstepper 60 coupled to the lead screw 38 of the workpiece repositioning mechanism 36 to reposition the ingot 14 relative to the ingot 14. 4A and 4B further illustrate rollers 40 that may be coupled with a pair of rails 68 to facilitate ingot 14 precisely and translationally positioned by microstepper 60. As shown, prior to the cropping operation, which may also be performed by the apparatus 10 in addition to the task of thinly cutting the wafer, the ingot 14 has a flanged tail opposite the somewhat tapered head 62. (64) is also provided.

The apparatus 10 includes one or more microstepper feed drives 50 of the wire propagation mechanism 30, a drive motor 56 of the wire drive mechanism 16, a workpiece rotating mechanism, as described in more detail below. And a controller 66 that operatively controls and engages the functions and internal related operations of the microstepper 58 of the 24 and the microstepper 60 of the workpiece repositioning mechanism 36.

5, an exemplary alternative embodiment of the apparatus 10 'according to the present invention is shown. The apparatus 10 'has a plurality of cutting wires 12' in the form of individual closed loop wires so that simultaneous cutting in the ingot 14 can be made to thinly cut individual wafers. The wire 12 ′ of the wire drive mechanism 16 ′ may be driven by the capstan 18 ′ by being supported by a plurality of pulleys 20 ′ and rotating and engaged in a single rotational direction of the drive motor 56 ′. have. The wire propagation mechanism 30 'of the apparatus 10' moves the wire drive mechanism 16 'in the horizontal direction with respect to the ingot 14 located vertically by the microstepper feed drive 50'. Workpiece rotation mechanism 24 ′ in the illustrated embodiment is mounted and secured to the cropped end of ingot 14. As shown, the device 10 'is provided with a catch jaw 70 and a catch table 72, or a wire drive mechanism 16' for cutting wafers from the ingot 14 as well as conveying the ingot. A workpiece repositioning mechanism (not shown) to position the ingot 14 relative to the ingot 14.

In the embodiment of the apparatus 10 described above with respect to FIGS. 1-4B, the capstan 18 may have a wire 12 of 30-60 m (100-200 feet) in a straight line, and 600-750 The wire 12 may be driven in reverse rotation at a speed of 2000 to 2500 ft / sec. However, in some applications, the wires together with the wire drive mechanism 16 'to move one or more wires 12' (eg, as shown in Figure 5) in a single direction without the need for reversal. It may be desirable to use one or more continuous loops of (12 '). As will be appreciated, these continuous loop (s) of wire 12 'will last longer than the corresponding reverse length of wire 12 and may be caused by the reverse action of wire 12 and may be relatively Any tooth marks that may provide a reduced cutting time may also be removed and at the same time try to settle more into the final cut of the ingot 14.

In each of the embodiments described above, rotation in one direction of the ingot 14 associated with the movement of the wire 12 means that the wire is only tangentially in tangential contact with the outer periphery of the ingot within the cut over the entire cutting operation. . This allows for more rapid cuts on the wire 12 which allows for faster cutting while simultaneously providing the use of finer gauge wire than in other cases where the ingot has to travel from the outer diameter of the ingot 14 through its center point to the maximum diameter of the ingot 14. Cause a small drag. The potential use of these finer gauge wires 12 results in less loss of ingot 14 material during sawing operations, and the cleaner cuts provided reduce the need for a wide range of polishing operations, thereby reducing abrasive material and operation. This means reducing the cost.

Another advantage is found by selecting the repetitive rotation of the ingot 14 through the variable arc during the cutting operation. Most silicon ingots have a number of surface undulations or defects on the outer surface of the cylindrical ingot. Often, the outer surface is not entirely flat and may have a surface shape with a helical set of gentle ridges similar to the outer surface of the soft ice cream cone. The appearance of such helical protrusions or ridges tends to pull the wire saw to one side or the other during the continuous rotational operation of the wire saw mechanism 10. The reciprocating motion through the arc rotates the ingot 14 in one direction and then in the opposite direction so that the lateral pressure on the wire saw caused by this defect is effectively removed. In this alternative mode of operation, the wire saw completes the cut by proceeding fully through the ingot 14 rather than ending the cut at the center. However, it can be seen that the improved precision achieved using the reciprocating movement of the workpiece is greater than in the continuous rotation state when the surface defects on the ingot 14 become important.

The speed of the wire 12 provided by the wire drive mechanism 16, the speed of rotation of the ingot 14 provided by the workpiece rotating mechanism 24, and the ingot of the wire 12 by the wire advancing mechanism 30. Progress to 14 must be precisely controlled by, for example, controller 66 (FIG. 3). Functionally, the surface speed of the wire 12 relative to the material of the ingot 14 is most preferably kept relatively constant. Therefore, the relative speed of the wire 12 must be reduced as the cutting progresses from the outer diameter of the ingot 14 to the inner diameter in order to keep the surface speed substantially constant. The cutting pressure of the wire 12 is determined by the wire advancing mechanism 30.

According to the horizontal cutting device illustrated in FIGS. 1-4A and in particular in FIG. 4B, water may be used during the cutting operation as a lubricant for the wire 12 to clean the crystalline debris to extend the cutting life of the wire 12. . Other suitable techniques may also be used for the embodiment shown in FIG.

In the first embodiment, the ingot 14 rotates relative to the wire 12 while the wire 12 reciprocates or continuously travels in contact with it. In the first case, the wire 12 is cut tangentially around the perimeter of the ingot as it progresses from the outer diameter of the ingot 14 to the inner diameter or the center. In the second case, the arc cutting through the ingot is performed in a tangential direction through the arc. Thus, in the second case, the traveling mechanism 30 moves the wire 12 through the ingot 14 completely. This same relative movement may be achieved by keeping the ingot 14 stationary and rotating the wire 12 about the longitudinal axis of the ingot 14 as the wire 12 repeatedly moves or proceeds continuously.

6A and 6B, a second preferred embodiment 100 of the present invention is shown in plan view, in which the ingot remains fixed and the wire saw is rotated about the ingot. FIG. 6A shows an apparatus with a wire saw at an intermediate cutting depth between the outer and inner diameters of ingot 14. FIG. 6B shows a device having a wire saw at different angular positions with respect to the outer diameter of the ingot 14 as described in more detail below.

Apparatus 100 comprises a cutting wire in a suitable part, for example a diamond-containing wire such as a cutting wire of the trade name "Superwire" or "Superlock" series available from Laser Technology West, Limited, Colorado Springs, Colorado, USA. do. Wire 102 is a method of the present invention for precisely and quickly thinning the silicon ingot 14 into a plurality of wipers for continuous processing, which become separate or integrated circuit devices by rotating the saw relative to the stationary ingot 14. Used with device 100.

The device 100 includes a wire drive mechanism 106 and a stationary frame 104 that move the wire 102 in a single direction indicated by arrow "a" or in a reciprocating manner with respect to the ingot 14. In the second embodiment shown, the wire drive mechanism 106 may include a capstan 108 that winds or unwounds the wire 102 relative to the center pulley to provide reciprocal movement to the wire 102. Alternatively, if one or more individual continuous loops of wire 102 are used instead of a single linear length of wire, wire 102 may be easily moved continuously in a single direction without reversal. As shown, the wire 102 may be guided in the vicinity of the ingot 14 by a pair of pulleys 110 while maintaining proper tensioning of the wire 102 by the tension pulley 112.

The device 100 moves the wire drive mechanism 106 about the ingot's longitudinal axis as the wire 102 moves in a single direction or in both directions, ie, orthogonally, in a reciprocating motion with respect to the ingot 14 as described above. It further includes a wire (ie, saw) drive mechanism rotating mechanism 114 for rotating.

In a second preferred embodiment, shown in FIG. 6, the wire saw rotating mechanism 114 includes an outer periphery stationary ring gear 116 centered relative to a support for the ingot 14 on the stationary frame 104, and a ring. Annular support disk 118 centered about the longitudinal axis of ingot 14 for rotation within gear 116, and annular support disk 118 about its central axis and the longitudinal axis of ingot 14; It may also include a drive motor and gear 120 mounted on frame 104 or support disk 118 to rotate about it.

As shown in FIGS. 6A and 6B, the ingot 14 is mounted in a chuck held in a fixed position on the frame 104. The drive motor 120 is mounted on one leg 119 of the annular support disk 118. The support disk 118 is also shown to have a generally trapezoidal shape with three legs 119 spaced 120 ° apart and a generally rectangular opening 121 around the ingot 14. Each leg 119 supports a gear 123 that engages with the teeth on the ring gear 112 such that the support disk 118 is held centrally with respect to the ingot 14. Two of the gears 123 are simply driven gears. The gear 123 meshed with the drive gear on the motor 120 is a driven gear for rotating the trapezoidal annular disk 114. This motor 120 may be a stepper motor or other suitable precisely controllable motor to execute the angular velocity required for the cutting operation as described in more detail with respect to the first embodiment described above.

The shape of the trapezoidal disk 114 is merely exemplary. This shape may be circular, triangular or a completely different shape, but in this embodiment is generally annular with a central opening located around the support for ingot 14. The annular support disk or plate 118 rotates around the ingot 14 because the wire drive mechanism 106 is fixed to the annular support disk 118. Since the annular support disk 118 rotates around the ingot 14, the wire 102 remains ingot while keeping the incision in the ingot 14 as the wire 102 is driven by the wire drive mechanism 106. Rotate again around (14).

The apparatus 100 also includes a wire propagation mechanism 30 in the second embodiment 100 illustrated in FIGS. 6A and 6B, as in the first embodiment where the wire drive mechanism 106 is mounted. The wire propagation mechanism 30 acts like moving the frame 113 radially relative to the wire drive mechanism 106 and is self-fixed to the rotating annular support disk 118. The wire propagation mechanism 30 is cut once while the saw rotation system 114 continuously rotates the wire propagation mechanism 30 and the wire drive mechanism 160 around the ingot 14 via the motor 120. In order to terminate the wire drive mechanism 106, i.e., the moving wire 102, from the initial position close to the outer diameter ("OD") of the ingot 14 as shown in FIG. 6B through the intermediate position shown in FIG. 14) to advance toward the final position close to the inner diameter ("ID"). When the wire 102 reaches the inner diameter or central longitudinal axis of the ingot 14, the ingot 14 is cut and the movement of the wire propagation mechanism 30 causes the wire 102 to retract towards the initial position 32. May be reversed.

Optionally, the saw rotation system 114 may be driven back and forth reciprocally through a set of deformable arcs rather than continuous as described above. In this alternative, the wire saw 102 cuts the curved cutout while the wire saw 102 substantially contacts the curved portion throughout the cutting operation through the diameter of the ingot 14. Wire saw 102 travels through ingot 14 as a whole in this alternative. In addition, the angle or length of the arc of reciprocation may be varied in some way throughout the cut. For example, the arc angle in each direction is small at the beginning and end of the cut through the diameter of the ingot 14 and is greater, for example about 45 ° toward the middle portion of the cut through the ingot 14. It may be. However, the purpose of rotation is the same. In other words, the wire saw is kept substantially in contact with the cut portion. This minimizes the lateral forces of the wire saw caused by defects or undulations in the outer surface of the ingot 14.

In operation, the speed imparted to the wire 102 by the wire drive mechanism 106, the saw rotational speed imparted by the saw rotating mechanism 114, and the ingot of the wire 102 by the wire advancing mechanism 30 14 All radial internal progression into the system must be precisely controlled. Functionally, it is most desirable that the surface velocity of the wire 102 remain relatively constant relative to the material of the ingot 14. Therefore, as in the first embodiment, the relative speed of the wire 102 relative to the ingot 14 is such that the cutting proceeds from the outer diameter of the ingot 14 to its center or inner diameter in order to keep the surface speed substantially constant. Should be reduced accordingly. As in the first embodiment, the cutting pressure of the wire 102 is determined by the wire propagation mechanism 30.

The two embodiments 10, 100 described and shown function very similarly in terms of ingot 14. In these two embodiments, the wires 12, 102 move continuously or repeatedly in motion around the periphery of the ingot 14 while cutting in contact with the ingot 14 perpendicular to the longitudinal axis of the ingot. This relative movement between the saw wire and the ingot 14 ensures that extremely narrow cuts and even cuts are maintained during cutting. Rotation of the repetitive motion minimizes the effect on the wire for changes in the outer ingot surface shape. Continuous rotation minimizes the depth of cut required to cut the end of the ingot and / or to cut the wafer from the ingot.

In the foregoing description of the principles of the invention in conjunction with specific device and wire cutting techniques, it will be clearly understood that the foregoing description has been made by way of example only and is not intended to limit the scope of the invention. In particular, it is recognized that the foregoing disclosure will suggest other modifications to those skilled in the art. Such modifications include other features that are already known per se and may be used in place of or in addition to the features already described herein. Although the claims set forth this application as specific combinations of features, the scope disclosed herein is, whether or not related to the same inventions as the presently claimed claims, and as described by the present invention. It also includes novel features or concepts or modifications that will be apparent to those skilled in the relevant art, or novel combinations of clearly or unclearly disclosed features, whether or not alleviating some or all of the problems. The Applicant thereby places the basis for creating a new claim on these features and / or a combination of such features during the performance of the present application or further applications derived therefrom.

Claims (60)

In a method for dividing a substantially cylindrical crystalline workpiece, Providing a wire with a plurality of cutting elements attached thereto; Moving the wire perpendicular to the longitudinal axis of the workpiece to form a cut in the workpiece; Rotating the wire relative to the workpiece to form the cut portion circumferentially around the workpiece; Advancing the wire from a first position adjacent to an outer diameter to a second position adjacent to an inner diameter as the wire of the workpiece deepens the cutout; Method comprising a. The method of claim 1 wherein said rotating step is performed by rotating said wire about a longitudinal axis of said workpiece. The method of claim 1 wherein said moving step is performed by drawing said wire linearly in one direction with respect to the longitudinal axis of said workpiece. The method of claim 1, wherein the moving step includes linearly drawing the wire in one direction with respect to the longitudinal axis of the workpiece and alternately withdrawing the wire in a second opposite direction with respect to the longitudinal axis of the workpiece. Method carried out by the step. The method of claim 1 wherein the moving and rotating steps are related to speed. 6. The method of claim 5, wherein the rotating step is performed at a substantially uniform angular velocity and the moving step is performed at a variable speed that decreases as the wire travels from the first position to the second position. . 6. The method of claim 5 wherein said moving step is performed at a substantially uniform speed and said rotating step is performed at a variable angular velocity that decreases as said wire travels from said first position to said second position. . The method of claim 1, wherein said advancing step is performed at a substantially uniform speed from said first position to said second position. The method of claim 1, further comprising retracting the wire from the second position to the first position. 10. The method of claim 9, further comprising repositioning the workpiece relative to the wire and repeating the moving, rotating, and advancing steps. The method of claim 1, wherein the providing and moving steps comprise providing a plurality of wires, each having a plurality of attached cutting elements, in a generally parallel and spaced relationship and perpendicular to the longitudinal axis of the workpiece. Moving the same time simultaneously. In a device for dividing a substantially cylindrical crystalline workpiece, A wire having a plurality of cutting elements attached thereto; A wire drive mechanism for moving the wire perpendicular to the longitudinal axis of the workpiece; A rotary mechanism coupled to a wire drive mechanism to rotate the wire drive mechanism about the longitudinal axis or to a workpiece to rotate the workpiece about the longitudinal axis; A wire running mechanism for positioning the wire from a first position adjacent the outer diameter to a second position adjacent the inner diameter; Apparatus, characterized in that provided. 13. The apparatus of claim 12, wherein the wire has a plurality of diamonds contained therein. The apparatus of claim 13, wherein the wire has a steel core having a copper sheath surrounding the exterior. 15. The apparatus of claim 14, wherein the plurality of diamonds are contained within the copper sheath. The apparatus of claim 15, wherein the wire further comprises a layer of nickel positioned over the copper sheath. 16. The apparatus of claim 15, wherein the plurality of diamonds are substantially uniformly distributed over the circumference and length of the wire. 13. The apparatus of claim 12, wherein the wire drive mechanism is operative to draw the wire linearly in one direction with respect to the longitudinal axis of the workpiece. 19. The apparatus of claim 18, wherein the wire is a wire in a closed loop. 13. The device of claim 12, wherein the wire drive mechanism is operable to linearly draw the wire in a first direction with respect to the longitudinal axis of the workpiece and alternately withdraw the wire in a second opposite direction with respect to the longitudinal axis of the workpiece. Device characterized in that. 21. The device of claim 20, wherein the wire is a long length of wire. 13. The rotating mechanism of claim 12, wherein the rotating mechanism is an annular ring gear coaxially mounted about the workpiece and a wire driving mechanism rotatably coupled to the ring gear to rotate the wire driving mechanism about a longitudinal axis. And a support. 23. The apparatus of claim 22, wherein the ring gear is stationary. 13. The apparatus of claim 12, further comprising a plurality of wires in a generally parallel and spaced apart relationship, each having a plurality of attached cutting elements, and a wire drive mechanism for moving the plurality of wires perpendicular to the longitudinal axis of the workpiece. Device characterized in that. Providing a wire with a plurality of cutting elements attached thereto; Moving the wire perpendicular to the longitudinal axis of the crystalline semiconductor material ingot and simultaneously rotating the wire about the longitudinal axis or rotating the ingot about the longitudinal axis; And advancing the wire from a first position adjacent the outer diameter of the ingot to a second position adjacent the inner diameter. 27. The semiconductor wafer of claim 25, wherein said providing step is performed by a diamond containing wire. 26. The semiconductor wafer of claim 25, wherein said moving comprises linearly drawing the wire in one direction with respect to the longitudinal axis of the ingot while rotating the wire about the longitudinal axis of the ingot. 26. The method of claim 25, wherein the moving step further comprises linearly drawing the wire in one direction with respect to the longitudinal axis of the ingot and alternately withdrawing the wire in a second opposite direction with respect to the longitudinal axis of the ingot. A semiconductor wafer comprising a. 26. The semiconductor wafer of claim 25, wherein said moving and rotating steps are related to speed. 30. The semiconductor of claim 29 wherein said rotating step is performed at a substantially uniform angular velocity and said moving step is performed at a variable speed that decreases as said wire travels from said first position to said second position. wafer. In a method of cutting a substantially cylindrical crystalline workpiece, Providing a wire with a plurality of cutting elements attached thereto; Moving the wire perpendicular to the longitudinal axis of the workpiece to form a cut in the workpiece; Reciprocating the wire through at least a first arc with respect to the workpiece while maintaining the wire substantially tangential to the circumference of the workpiece within the cutout; Advancing the wire from a first position adjacent the outer diameter of the workpiece to a second position through the workpiece; Method comprising a. 32. The method of claim 31, wherein said reciprocating step is performed by rotating said wire about said longitudinal axis of said workpiece. 32. The method of claim 31, wherein said moving step is performed by linearly drawing said wire in one direction about a longitudinal axis of said workpiece. 32. The method of claim 31, wherein the moving comprises linearly drawing the wire in a first direction with respect to the longitudinal axis of the workpiece, and the wire in a second direction opposite to the longitudinal axis of the workpiece. Characterized in that it is carried out by the step of withdrawing alternately. 32. The method of claim 31 wherein the moving and rotating steps are related to speed. 36. The method of claim 35, wherein the rotating step is performed in each direction at a substantially constant angular velocity, and the moving step is performed at a variable speed as the wire proceeds from the first position to the second position. Way. 36. The method of claim 35, wherein said moving step is performed at a substantially constant speed and said rotating step is performed at a variable angular velocity as said wire proceeds from said first position to said second position. 32. The method of claim 31 wherein said advancing step is performed at a substantially constant angular velocity from said first position to said second position. 32. The method of claim 31, further comprising retracting the wire from the second position to the first position. 40. The method of claim 39, further comprising repositioning the workpiece relative to the wire and repeating the moving, reciprocating and advancing steps. 32. The method of claim 31, wherein said providing and said moving step comprise providing a plurality of wires each having a plurality of cutting elements attached thereto in a substantially parallel and spaced apart relationship; Simultaneously moving vertically relative to each other. In a device for cutting a substantially cylindrical crystalline workpiece, A wire with a plurality of cutting elements attached thereto, A wire drive mechanism for moving the wire perpendicular to the longitudinal axis of the workpiece; A rotary mechanism coupled to one of the wire drive mechanism or the workpiece to reciprocally rotate the wire drive mechanism about the longitudinal axis or to rotate the workpiece about the longitudinal axis; A wire running mechanism for placing the wire from a first position adjacent the outer diameter of the workpiece to a second position through the workpiece; Apparatus comprising a. 43. The apparatus of claim 42, wherein the wire comprises a plurality of diamonds contained in the wire. 44. The apparatus of claim 43, wherein the wire comprises a steel core having a copper sheath surrounding the perimeter. 45. The apparatus of claim 44, wherein the plurality of diamonds are contained within the copper sheath. 46. The apparatus of claim 45, wherein the wire further comprises a nickel layer covering the copper sheath. 46. The apparatus of claim 45, wherein the plurality of diamonds are substantially uniformly distributed around the circumference and length of the wire. 43. The apparatus of claim 42, wherein the wire drive mechanism is operative to linearly draw the wire in one direction with respect to the longitudinal axis of the workpiece. 49. The device of claim 48, wherein the wire comprises a closed loop of wire. 43. The device of claim 42, wherein the wire drive mechanism is operated to linearly withdraw the wire in a first direction with respect to the longitudinal axis of the workpiece and alternating the wire in a second direction opposite to the longitudinal axis of the workpiece. And operate to withdraw. 51. The device of claim 50, wherein the wire comprises a long length of wire. 43. The rotational mechanism of claim 42, wherein the rotation mechanism is rotatably coupled to the ring gear coaxially mounted about the workpiece and to the rotational rotation of the wire drive mechanism about the longitudinal axis. And a wire drive mechanism support. 53. The device of claim 52, wherein the ring gear is stationary. 43. The apparatus of claim 42, further comprising a plurality of wires in a generally parallel and spaced apart relationship, each with a plurality of cutting elements attached thereto, wherein the wire drive mechanism perpendiculars the plurality of wires to the longitudinal axis of the workpiece. The device, characterized in that configured to move. Providing a wire with a plurality of cutting elements attached thereto; Moving the wire perpendicular to the longitudinal axis of the crystalline semiconductor material ingot, and simultaneously reciprocating the wire about the longitudinal axis or reciprocating the ingot about the longitudinal axis; Advancing the wire from a first position adjacent the outer diameter of the ingot to a second position through the workpiece A semiconductor wafer manufactured by the method comprising. 56. The semiconductor wafer of claim 55, wherein said providing step is performed by a diamond containing wire. 56. The semiconductor wafer of claim 55, wherein said moving comprises linearly drawing said wire in one direction about said longitudinal axis of said ingot while rotating said wire about said longitudinal axis of said ingot. . 56. The method of claim 55, wherein the moving step comprises linearly drawing the wire in a first direction with respect to the longitudinal axis of the ingot and in the second direction opposite to the longitudinal axis of the ingot. A semiconductor wafer comprising the step of taking out alternately. 56. The semiconductor wafer of claim 55, wherein said moving step and said rotating step are related to speed. 60. The method of claim 59, wherein the rotating step is performed in each direction at a substantially constant angular velocity, and the moving step is performed at a variable speed as the wire proceeds from the first position to the second position. Semiconductor wafer.