Crystal Wafer Processing System and Method

Abstract

A method for manufacturing a wafer or disk from an industrially grown crystal, the method comprising the steps of: scanning the crystal (1) quantitatively to form a 3D volumetric digital model of the crystal; recording the 3D spatial coordinates of defects (4, 4') detected during the scanning; measuring one or more crystal axes (C1, C2, C3) provided by the crystal structure of the crystal and recording the crystal axes in the 3D model of the crystal; extracting one or more cores (2) from the crystal (1) in a selected crystal axis direction that is parallel to one of the crystal axes or at an angle defined with respect to the crystal axes; slicing the core with a wafer slicing machine including a slicing tool comprising a plurality of cutting wires or blades spaced apart at a regular slice pitch (G) configured to cut wafers of the same thickness (S) from the core, orthogonally to the selected crystal direction; calculating an offset position (O) of the slicing tool along the selected crystal axis, the method being configured to minimize the number of wafers with defects; and adjusting the position of the slicing tool with respect to the core along the selected crystal direction according to the calculated offset.

Description

Technical Field

[0001] The present invention relates to a method for wafer processing large crystals such as sapphire, silicon or silicon carbide crystals for optical or electronic applications, in particular.

Background Art

[0002] Industrially grown crystals such as sapphire crystals typically weigh from several kilograms to several hundred kilograms and may have an irregular outer shape that is approximately conical / cylindrical. A typical process is to extract a cylindrical core from this irregular 3D shape, as shown in the photograph of Figure 1 showing an industrially grown sapphire crystal, and then slice these cylindrical cores into disks or circular wafers as shown in Figure 2. The orientation of the axis of the cylindrical core is in a defined direction with respect to the crystal structure of the crystal and may correspond, for example, to one of the optical axes of the crystal. Usually, in industrial applications, disks or wafers of a certain diameter and thickness are required, and depending on the size and shape of the raw crystal, the position and number of cylindrical cores will vary for each raw crystal.

[0003] In general, it is understood that the extracted cores can have a circular, rectangular, or any other cross-section. It is also understood that a "disk" or "wafer" is a general term for the parallel portions sliced from the core, regardless of the shape or thickness it has.

[0004] In conventional processes, the crystal structure axes are determined by measurements performed by X-ray or optical measurement tools, and the optimal distribution of cores extracted from a particular crystal can be done with the help of a human operator who determines the best layout.

[0005] However, these processes are very time-consuming and costly. Furthermore, due to internal defects present within the crystal, there is a certain amount of waste that ends up in the disks or wafers sliced from the selected core. Since the growth of such crystals is time-consuming and costly, there is an advantage in reducing the amount of waste and defective disks or wafers. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] In view of the above, an object of the present invention is to provide a system and method for wafer processing of industrially grown crystals that reduce waste and improve the yield of the wafer processing process.

[0007] It is advantageous to provide a wafer processing treatment for industrially grown crystals that enables the production of crystal disks or wafers with a low defect rate and very high quality.

[0008] It is advantageous to provide a process for wafer processing of industrially grown crystals that is rapid and economical, particularly enhancing automation and reducing the intervention of human operators. MEANS FOR SOLVING THE PROBLEMS

[0009] The object of the present invention has been achieved by providing the crystal wafer processing method according to claim 1.

[0010] Disclosed herein is a method for manufacturing wafers from industrially grown crystals, scanning the crystal quantitatively to form a 3D volumetric digital model of the crystal, recording the 3D spatial coordinates of the defects detected during the scanning, measuring one or more crystal axes (C1, C2, C3) provided by the crystal structure of the crystal and recording this crystal axis in the 3D model of the crystal, In a selected crystal axis direction that is parallel to one of the crystal axes or at a defined angle with respect to the crystal axis, the step of extracting one or more cores from the crystal; A wafer slicing machine including a slicing tool that includes a plurality of cutting wires or blades spaced apart at a regular slice pitch (G) configured to cut wafers of the same thickness (S) from the core, and slicing the core orthogonally to the selected crystal direction; including This method calculating an offset position (O) of the slicing tool along the selected crystal direction configured such that the number of defective disks or wafers is minimized; adjusting the position of the slicing tool with respect to the core along the selected crystal direction according to the calculated offset.

[0011] In one embodiment, the offset position has an amplitude that varies in the range from 0 to the thickness of the slice pitch (G) of the wafer.

[0012] In an advantageous embodiment, the scanning of the crystal includes optical scanning of the crystal.

[0013] In an advantageous embodiment, the core is placed in a holder, and the holder and the core are positioned within the slicing machine.

[0014] In an advantageous embodiment, the crystal axis of the core is measured again after the core is cut out from the crystal, the core axis position is adjusted by the holder, and the slicing tool cuts the wafer orthogonally to the adjusted crystal axis.

[0015] In an advantageous embodiment, the core with the maximum diameter (Dmax) cut out from the crystal is positioned such that the number of defects found in the wafer cut out from the crystal is minimized by calculation using a 3D volume digital model.

[0016] In an advantageous embodiment, the absolute value of the offset is calculated from a reference position on the surface of the crystal before the operation of removing the core.

[0017] In an advantageous embodiment, the scanning step of the defects and shape of the crystal is performed after the operation of cutting off the upper end portion and / or the lower end portion of the raw crystal.

[0018] In an advantageous embodiment, the crystal includes a plurality of crystal axes, and the method includes a step of generating a flat plane that intersects the core or the wafer, the flat plane being parallel to the axis of the core and perpendicular to the crystal axis, a step of calculating the number of defects between the flat plane and the outer contour of the core or the wafer, and a step of selecting one of the flat planes for cutting such that the maximum number of defects is positioned within the removal area between the flat plane and the outer contour.

[0019] In an advantageous embodiment, a non-circular pattern, such as a pattern of semiconductor chips cut out from a wafer, is oriented according to one of a plurality of crystal axes (C2, C3) calculated such that the minimum number of defects is found within the area of the chip or within the minimum number of chips, and the maximum number of defects is found within the removal area between the outer contour of the chip pattern and the outer circular peripheral edge of the wafer.

[0020] In an advantageous embodiment, the pattern of the chip is included in a 3D volumetric digital model of the crystal to calculate an offset to take into account defects located in the waste area between the outer diameter of the wafer and the chips cut out from the wafer.

[0021] Also disclosed herein is a system for manufacturing wafers from industrially grown crystals, the system including a scanner for scanning the crystal quantitatively, and a program module configured to form a 3D volumetric digital model of the crystal from the output of the scanner, the program module being further configured to record the 3D spatial coordinates of the defects detected by the scanner. The program module is configured to calculate the offset position (O) of the slicing tool along a selected crystal axis configured such that the number of wafers having defects is minimized.

[0022] In an advantageous embodiment, the scanner for scanning the crystal comprises an optical scanner.

[0023] In an advantageous embodiment, the system further comprises a measuring device for measuring one or more crystal axes (C1, C2, C3) provided by the crystal structure of the crystal and recording the one or more crystal axes in the 3D model of the crystal.

[0024] In an advantageous embodiment, the system a core extraction device for cutting out one or more cylindrical cores (2) from the crystal (1) in a selected crystal axis direction, and a wafer slicing machine comprising a slicing tool including a plurality of cutting wires or blades spaced apart at a regular slicing pitch (G) configured to cut wafers of the same thickness (S) from the core.

[0025] The system may be configured to implement any of the above-described embodiments of the method of manufacturing wafers.

[0026] Further objects and advantageous aspects of the present invention will become apparent from the claims, as well as from the following detailed description and the accompanying drawings.

Brief Description of the Drawings

[0027]

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DETAILED DESCRIPTION OF THE INVENTION

[0028] Referring to the figures, an industrially grown raw crystal 1 has a generally conical irregular 3D shape 9 and has a crystal structure that defines one or more crystal axes corresponding to a specific orientation of the crystal lattice. For example, in the case of a sapphire crystal, there is an optical axis (generally also called the c-axis) C1 that eliminates the inherent birefringence characteristics of the sapphire crystal. The selected crystal axis C1 can also be located within the crystal plane that is most resistant to the force applied perpendicularly. This plane can be 20% more difficult to process compared to other crystal orientations. In many applications, it is desirable to cut the wafer at a specific angle with respect to one or more axes, for example perpendicular to the optical axis C1.

[0029] In the case of semiconductor circuits, the orientation of the crystal lattice is also important, and the wafer should be cut with respect to a specific direction within the crystal. The direction of the crystal lattice can be determined by various well-known measuring means, for example, using an optical or x-ray measurement system.

[0030] Once the axis is determined, the orientation of the cylindrical core from which the disk or wafer is cut can be defined within the volume of the raw crystal. In many applications, the desired diameter Dn of the wafer is predefined, but in the raw crystal, wafers of different diameters or surface areas can be extracted for potentially different applications or for the same application. For example, with respect to sapphire crystals, wafers of different diameters can be used to manufacture different-sized lenses for optical devices. Typically, wafers with a larger diameter are more valuable and scarcer, and clearly fewer wafers can be extracted per raw crystal (there may even be only one).

[0031] After determining the selected core, the appropriate core cutting tool 6 can be used to cut out the cylindrical cores 2, 2a, 2b, 2c.

[0032] Regarding the subsequent wafer slicing process, the core is typically placed within a polymer holder or support 8, which is adhered to the crystal core and sacrificed during the wafer slicing process.

[0033] The support 8 is manufactured by an additive process such as 3D printing, or by a subtractive process such as a molding process or machining from a block of support material, and can be adjusted to fit the shape and size of the core. In this regard, a crystal axis such as the optical axis C1 is determined for extracting the core, but the measurement may be slightly inaccurate, and further correction of the crystal axis can be performed depending on the position of the core 2 within the support 8. This enables, for example, the wafer to be cut with higher accuracy orthogonal to the measured crystal axis C1, with the support 8 positioned within the wafer slicing machine.

[0034] Disk or wafer slicing machines are typically formed of a plurality of wires (typically diamond-coated wires or blades) that are spaced at regular intervals and pass through the core orthogonally to a particular direction (e.g., the optical axis).

[0035] It should be noted that the direction through the core can be determined by the crystal axis, but is not necessarily equal to the crystal axis. For example, in some applications, sapphire is cut at an angle offset by 20.5° with respect to the optical axis. As used herein, the term "crystal direction" corresponds to the "direction through the core", which, as described above, may be parallel to the crystal lattice axis or at an angle defined with respect to the crystal lattice axis.

[0036] Cooling and lubricating fluids can be used during core removal and slicing, and such processes typically take several hours or days. The core removal and slicing process of wafers is a process well known per se and need not be further described herein. The two disks at the core ends can be rejected as waste, and then the slices are typically reinspected to determine those that are defect-free or have defects below an acceptable threshold, and those with defects exceeding the threshold are rejected. In many industrial wafer processing processes, it is common for about 5% to 30% of the sliced disks to be rejected due to internal crystal defects, which depends greatly on the quality of the crystal itself and the diameter of the disk or wafer.

[0037] According to one aspect of the present invention, prior to the core removal process, but optionally after boule cropping and the grinding or slicing process of the upper and lower ends, a complete 3D scan of the crystal is performed, and the three-dimensional X, Y, Z coordinates of each defect within the volume of the crystal are mapped. These X, Y, Z coordinates can be mapped relative to a geometric reference (point, line, plane) fixed to the crystal or to the edge of the core. The raw crystal, or a holder fixed to the raw crystal, can have its reference point or shape marked. Thus, a digitized 3D model of the crystal can be constructed, along with the defects located therein.

[0038] The crystal axes are measured by a measuring instrument known per se, such as using x-rays, and these crystal axis directions are also recorded in the digitized 3D model of the crystal.

[0039] The core can then be selected to be cut out of the crystal in a selected crystal axis direction, and the position of the core is optimized to ensure that the most valuable core, which is the largest core, has the fewest defects within its volume. This optimization can be performed with the aid of a computer program that attempts to minimize the number of defects within a core of a given diameter by varying the position of the core within the raw crystal and counting the defects for each position.

[0040] Accordingly, the computer-aided optimization process can be configured to place the largest diameter core at the most optimal location, i.e., the location within the core volume with the least amount of defects, and then position the remaining smaller diameter cores within the remaining volume around the largest core. If there are the largest core, the second largest core, and cores smaller in size than the second largest core, the optimization process can position the second largest core at the optimal location with the least amount of defects within this core before positioning the remaining cores. Depending on the application, the cores can have a predetermined diameter, or their diameters can be different from a single large core having the largest possible diameter within the as-grown crystal and other cores of smaller diameters, and can optimize the volume of useful material and reduce the volume of waste. The latter depends on the requirements of the wafer according to the intended application. Alternatively, the optimization can also be performed to jointly maximize the value of all the extracted cores.

[0041] FIG. 3a shows a core, for example, of the maximum diameter Dmax extracted from an as-grown crystal, which has a useful volume 10 from which the wafer can be cut orthogonally to the crystal axis C1. As described above, the wafer is typically required for a specific application and the wafer is required to have a certain thickness S, which is cut with a wire cutter having a regular cutting grid.

[0042] Depending on the position of the cutting grid wire along the crystal axis, according to one aspect of the present invention, within the range between the minimum number of disks having defects and the maximum number of disks having defects, there can be a number of disks having defects 4. The spacing between the cutting wires corresponds to the range of possible axial positions of the wires, which can be adjusted to optimize the number of disks without defects, i.e., disks containing no defects or only defects less than the acceptable threshold defined by the requirements of the application.

[0043] According to one aspect of the present invention, the position of the cutting wire is adjusted by an offset O within the range between 0 and the grid pitch G between the cutter 7. The offset O can be added to an absolute value from a reference plane or point, such as the end face 5 of the core, or any other fixed reference point or shape on the raw crystal 1, the crystal core 2, or the holder 8. This process can be automated in a simple manner using a digital 3D model of the crystal in which the X, Y, Z positions of the defects and the crystal axis direction are recorded, whereby the calculation of the optimal offset can be performed at any time before wafer slicing, including before extracting the crystal core 2 from the raw crystal 1. The position of the offset O can be adjusted relative to any other reference position provided, for example, on the core holder. The correction of the offset position and the position of the crystal relative to the machine can be done either by changing the position of the core on the holder, or by adjusting the position of the holder 8 relative to the cutting machine or by adjusting the shape of the holder so as to present a reference plane for sending an instruction to the cutting machine to adjust the position of the holder such that the cutting grid is correctly positioned relative to the reference position of the core or its holder according to the calculated offset.

[0044] In the calculation of the offset, the thickness of the material removed during the slicing process is taken into account, and the optimization process can vary the offset from 0 to the grid pitch G to determine the number of wafer slices having defects below a predetermined tolerance threshold, whereby some defects may be within the thickness B of the removed material and thus disappear from the wafer or defects that may be present in two adjacent wafers are shifted into one wafer.

[0045] In FIG. 3c, taking the defects found in the example of FIG. 3a as an example, an offset was calculated from a reference point on an outer point on the surface 9 of the crystal, and as a result of corresponding to an offset of 68.5 mm, defects were found in 3 out of 18 wafer slices. These 3 wafers are represented by the black areas in FIG. 3c. At the non-optimal offset of 69.5 mm in this particular embodiment, the number of wafer slices containing defects is 6 (FIG. 3d). Thus, in this example, an important advantage is to calculate the optimal offset and offset the position of the wire grid along the selected crystal axis to reduce waste. Furthermore, the scanning of defects, subsequent 3D modeling of the spatial coordinates of the defects, and the crystal axis and the outer profile of the crystal that help provide the reference point enable an automated and accurate adjustment of the optimal cutting arrangement for reducing waste.

[0046] Referring to FIG. 4, in certain applications, a flat surface parallel to the cylinder axis and orthogonal to the crystal axis or crystal direction is required. In some crystals, such axes or directions are replicated by crystal symmetry, thus providing a plurality of equivalent directions C1.1, C1.2, C1.3 for positioning the flat plane. In such applications, the spatial coordinates of the defects 4, 4' can be used to optimize the selection of the flat cutting planes 13a, 13b, 13c that form the chords of the cylinder, and a flat chord surface having the most defects 4' within the waste volume 11 can also be generated. Cutting out a flat chord surface from a core or a wafer disk can be used in various applications, including, for example, marking the crystal lattice orientation on a semiconductor crystal.

[0047] Referring to FIG. 5, the spatial coordinates of the defects 4, 4' may be used to optimize the subsequent orientation of the chip according to one of the equivalent crystal directions C2.1, C2.2 (e.g., parallel or orthogonal to the crystal axes) such that the selection of the cut-off offset and the rotation of the surface area covered by the chip 12 are such that as many inclusions as possible are found within the waste area 11 between the outer circular periphery and the rectangular profile of the chip. In the example shown in FIG. 4, it is preferred to orient the chip 12 according to the crystal direction C2.2 rather than the crystal axis C2.1, because at the first angular orientation aligned with the crystal direction C2.2, there are fewer defects 4 within the area covered by the chip 12 than at the second angular orientation C2.1 where there are more defects 4' within the area covered by the chip 12'.

[0048] When the crystal is used in an application where the chip is to be extracted as shown in FIG. 5, for example a semiconductor chip from a silicon carbide crystal, the offset may also be adjusted to take into account inclusions found within the waste volume 11 at the periphery, between the circular periphery of the disk wafer and the actual chip.

[0049] Core removal machine Core cutting tool 6 Slicing machine Slicing wire 7 Crystal support 8 3D inspection machine Raw crystal 1 Outer profile / surface 9 Useful volume 10 Waste volume 11 Defect 4 Flat cut 13 Cylindrical core 2, 2a, 2b, 2c End face 5 Reference plane Disk / wafer 3 Chip 12 Crystal axes C1, C2, C3 Example: optical axis​ Equivalent crystal directions C1.1, C1.2, C1.3 and C2.1, C2.2 Example: Crystal axes Core diameter Dn Slice thickness S of the disk or wafer Thickness B of the cutting blade Offset O

[0050] 〔Embodiment〕 (1) A method for manufacturing a wafer or a disk from an industrially grown crystal, comprising: Scanning the crystal (1) quantitatively to form a 3D volume digital model of the crystal; Recording the 3D spatial coordinates of the defects (4, 4') detected during the scanning; Measuring one or more crystal axes (C1, C2, C3) provided by the crystal structure of the crystal and recording the crystal axes in the 3D model of the crystal; Extracting one or more cores (2) from the crystal (1) in a selected crystal direction that is parallel to one of the crystal axes or at a defined angle with respect to the crystal axes; Slicing the core with a wafer slicing machine including a slicing tool including a plurality of cutting wires or blades spaced apart at a regular slice pitch (G) configured to cut wafers of the same thickness (S) from the core, the slicing being perpendicular to the selected crystal direction; comprising: Calculating an offset position (O) of the slicing tool along the selected crystal direction, the method being configured to minimize the number of defective wafers; Adjusting the position of the slicing tool with respect to the core along the selected crystal direction according to the calculated offset. (2) The method according to embodiment 1, wherein the offset position varies within an amplitude ranging from 0 to the thickness of the slice pitch (G) of the wafer. (3) The scanning of the crystal in the method according to embodiment 1 or 2 includes optically scanning the crystal. (4) The method according to any one of embodiments 1 to 3, wherein the core (2) is placed in a holder (8), and the holder and the core are positioned in the slicing machine. (5) The method according to embodiment 4, wherein the crystal axis of the core is measured again after the core is cut out from the crystal, the core axis position is adjusted by the holder, and the slicing tool cuts the wafer perpendicular to the adjusted crystal axis.

[0051] (6) The method according to any one of embodiments 1 to 5, wherein the core (Dmax) with the maximum diameter cut out from the crystal is positioned such that the number of defects found in the wafer cut out from the crystal is minimized by calculation using the 3D volume digital model. (7) The method according to any one of embodiments 1 to 6, wherein the absolute value of the offset is calculated from a reference position on the surface of the crystal before the operation of removing the core. (8) The method according to any one of embodiments 1 to 7, wherein the scanning step of the defects and shape of the crystal is performed after the cutting operation of the upper end and / or lower end of the raw crystal. (9) The method according to any one of embodiments 1 to 8, wherein the crystal includes a plurality of equivalent crystal axes or a plurality of equivalent crystal directions (C1.1, C1.2, C1.3), and the method includes generating a flat plane (13a, 13b, 13c) that intersects the core or the wafer, the flat plane being parallel to the axis of the core and perpendicular to the crystal axis; calculating the number of defects between the flat plane and the outer contour of the core or the wafer; and selecting one of the flat planes for cutting such that the maximum number of defects (4') is positioned in the waste area (11) between the flat plane and the outer contour. (10) A method according to any of embodiments 1 to 9, wherein a non-circular pattern such as a pattern of a semiconductor chip (12) cut out from a wafer (3) is oriented according to one of a plurality of crystal directions (C2.1, C2.2) calculated such that a minimum number of defects (4) are found within the area of the chip or within a minimum number of said chips, and a maximum number of defects are found within a waste area (11) between the outer contour of the pattern of the chip and the outer circular peripheral portion of the wafer.

[0052] (11) The method according to embodiment 10, wherein the pattern of the chip calculates the offset so as to take into account the defects located in the waste area (11) between the outer diameter of the wafer and the chip cut out from the wafer, and is included in the 3D volume digital model of the crystal. (12) A system for manufacturing a wafer from an industrially grown crystal, comprising a scanner for quantitatively scanning a crystal (1) and a program module configured to form a 3D volume digital model of the crystal from the output of the scanner. The program module is further configured to record the 3D spatial coordinates of defects (4, 4') detected by the scanner. The program module is configured to calculate the offset position (O) of a slicing tool along a selected crystal axis configured such that the number of wafers having defects is minimized. (13) The system according to embodiment 12, further comprising a measuring device for measuring one or more crystal axes (C1, C2, C3) provided by the crystal structure of the crystal and recording the one or more crystal axes in the 3D model of the crystal. (14) A core extraction device for cutting out one or more cylindrical cores (2) from the crystal (1) in a selected crystal axis direction, A wafer slicing machine comprising a slicing tool including a plurality of cutting wires or blades spaced apart at a regular slice pitch (G) configured to cut wafers of the same thickness (S) from the core, and further comprising the system according to embodiment 12 or 13. (15) A system according to any one of embodiments 12 to 14, configured to perform the method according to any one of embodiments 1 to 11.

Claims

1. A method for manufacturing a wafer or disk from an industrially grown crystal, comprising: scanning the crystal (1) quantitatively to form a 3D volumetric digital model of the crystal; recording the 3D spatial coordinates of the defects (4, 4') detected during the scanning; measuring one or more crystal axes (C1, C2, C3) provided by the crystal structure of the crystal and recording the crystal axes in the 3D model of the crystal; extracting one or more cores (2) from the crystal (1) in a selected crystal direction that is parallel to one of the crystal axes or at a defined angle with respect to the crystal axes; slicing the core with a wafer slicing machine including a slicing tool comprising a plurality of cutting wires or blades spaced apart by a regular slice pitch (G) configured to cut wafers of the same thickness (S) from the core, orthogonally to the selected crystal direction; including calculating an offset position (O) of the slicing tool along the selected crystal direction, configured such that the number of defective wafers is minimized; adjusting the position of the slicing tool with respect to the core along the selected crystal direction according to the calculated offset.

2. The method according to claim 1, wherein the offset position has an amplitude varying in the range from 0 to the thickness of the slice pitch (G) of the wafer.

3. The method according to claim 1, wherein the scanning of the crystal includes optically scanning the crystal.

4. The method according to claim 1, wherein the core (2) is placed within a holder (8), and the holder and the core are positioned within the slicing machine.

5. The method according to claim 4, wherein the crystal axes of the core are measured again after the core is cut out of the crystal, the core axis position is adjusted by the holder, and the slicing tool cuts the wafer orthogonally to the adjusted crystal axes.

6. The method according to claim 1, wherein the core (Dmax) having the maximum diameter cut out from the crystal is positioned such that the number of defects found in the wafer cut out from the crystal is minimized by calculation using the 3D volumetric digital model.

7. The method according to claim 1, wherein the absolute value of the offset is calculated from a reference position on the surface of the crystal before the operation of removing the core.

8. The method according to claim 1, wherein the step of scanning the defects and shape of the crystal is performed after the operation of cutting off the upper end portion and / or the lower end portion of the raw crystal.

9. The crystal includes a plurality of equivalent crystal axes or a plurality of equivalent crystal directions (C1.1, C1.2, C1.3), and the method includes a step of generating a flat plane (13a, 13b, 13c) that intersects the core or the wafer, wherein the flat plane is parallel to the axis of the core and perpendicular to the crystal axis, a step of calculating the number of defects between the flat plane and the outer contour of the core or the wafer, and a step of selecting one of the flat planes for cutting such that the maximum number of defects (4') is positioned within the waste area (11) between the flat plane and the outer contour. The method according to claim 1.

10. The non-circular pattern, such as the pattern of the semiconductor chip (12) cut out from the wafer (3), is oriented according to one of a plurality of crystal directions (C2.1, C2.2) calculated such that the minimum number of defects (4) is found within the area of the chip or within the minimum number of the chips, and the maximum number of defects is found within the waste area (11) between the outer contour of the pattern of the chip and the outer circular peripheral portion of the wafer. The method according to claim 1.

11. The method according to claim 10, wherein the pattern of the chip is included in the 3D volume digital model of the crystal to calculate the offset so as to take into account the defects located in the waste area (11) between the outer diameter of the wafer and the chip cut out from the wafer.

12. A system for manufacturing a wafer from an industrially grown crystal, including a scanner for quantitatively scanning the crystal (1) and a program module configured to form a 3D volume digital model of the crystal from the output of the scanner. The program module is further configured to record the 3D spatial coordinates of the defects (4, 4') detected by the scanner. The system, wherein the program module is configured to calculate an offset position (O) of a slicing tool along a selected crystal axis configured such that the number of wafers having defects is minimized. **Claim 13** The system according to claim 12, further comprising a measuring device configured to measure one or more crystal axes (C1, C2, C3) provided by a crystal structure of the crystal and record the one or more crystal axes in the 3D model of the crystal. **Claim 14** A core extraction device for cutting out one or more cylindrical cores (2) from the crystal (1) in a selected crystal axis direction, A wafer slicing machine further comprising a slicing tool including a plurality of cutting wires or blades spaced apart at a regular slicing pitch (G) configured to cut wafers of the same thickness (S) from the core. **Claim 15** The system according to claim 12, configured to implement the method according to any one of claims 1 to 11.

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