PROCESSING METHOD AND SYSTEM FOR REDUCING THE CURVATURE OF NITROGEN-DOTED WAFERS

Abstract

Processing method for reducing the curvature of a nitrogen-doped wafer, comprising: Dividing (S201) a nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed according to a distribution of the nitrogen content of the nitrogen-doped crystal ingot to be cut, wherein each ingot segment to be processed corresponds to a nitrogen content range; Determining (S202) a processing state according to each crystal ingot segment to be processed according to the matches between nitrogen content ranges and processing states, wherein the processing state enables the corresponding crystal ingot segment to be processed to be prevented from bending during wire sawing; and Performing (S203) the cutting operation on each crystal ingot segment to be processed using the processing state corresponding to each crystal ingot segment to be processed, thereby obtaining a wafer by cutting the nitrogen-doped crystal ingot to be cut; wherein determining (S202) a processing state corresponding to each crystal ingot segment to be processed according to the correspondences between nitrogen content ranges and processing states comprises: Recording temperature values ​​at a variety of defined radial positions during the wire sawing process for each crystal ingot segment to be processed; Determining temperature differences between the multitude of crystal ingot segments to be processed based on the temperature values ​​at the same radial positions of the multitude of crystal ingot segments to be processed; Determining steel wire feed rates according to each crystal ingot segment to be processed based on the temperature differences between the multitude of crystal ingot segments to be processed, such that a processing temperature of crystal ingot segments to be processed, except for the crystal ingot segment to be processed at an upper end of the nitrogen-doped crystal ingot to be cut, is consistent with a processing temperature of the crystal ingot segment to be processed at the upper end of the nitrogen-doped crystal ingot to be cut.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of wafer manufacturing technologies, particularly to a processing method and system for reducing the curvature of nitrogen-doped wafers. GENERAL STATE OF THE ART

[0002] Currently, the process of producing large monocrystalline semiconductor silicon wafers uses monocrystalline silicon ingots (also referred to as "crystal ingots" or "silicon ingots" in some examples) grown using the Czochralski process. The Czochralski process involves melting polycrystalline silicon in a quartz crucible to obtain a silicon melt. A monocrystalline seed is immersed in the silicon melt, and the seed is continuously pulled away from a surface of the silicon melt. During the pulling process, a monocrystalline silicon ingot is grown at an interface.

[0003] In the conventional process of growing monocrystalline silicon ingots, nitrogen doping is typically used to dope the monocrystalline silicon crystal with trace amounts of nitrogen. Nitrogen can suppress defects (crystal-originated particles, COPs), which have a serious impact on the quality of integrated circuits, thereby improving the yield of integrated circuits.Oxygen precipitation and the generation of induced secondary defects in monocrystalline silicon ingots grown by the Czochralski process can also be promoted, and high-quality clean regions can be created in active areas on silicon wafer surfaces obtained by the subsequent dicing process, which is conducive to the gettering of metal impurities during the preparation of integrated circuit devices. Furthermore, the mechanical strength of silicon wafers can also be improved.

[0004] Currently, in the process of pulling crystal ingots using nitrogen doping technology, a segregation phenomenon occurs due to the small segregation coefficient of nitrogen, resulting in uneven nitrogen concentrations at different positions along the axial direction of the crystal ingot. For example, the nitrogen concentration at the bottom of the crystal ingot is usually higher than that at the top. Furthermore, because the degree of the effect achieved by nitrogen-doped monocrystalline silicon is usually determined by the nitrogen concentration, different mechanical strengths occur at different positions along the axial direction of the crystal ingot due to different nitrogen concentrations, leading to warpage during the cutting process.US 2016 / 0 236 375 A1 discloses a silicon carbide ingot comprising an end surface and an end surface opposite to the end surface; in the silicon carbide ingot, the end surface and the end surface face each other in a growth direction, and a gradient of a nitrogen concentration in the growth direction is not less than 1×10. 16 cm -4 and not larger than 1×10 18 cm -4CN 1 01 516 573 A discloses a cutting method comprising winding a wire around a plurality of grooved rollers and pressing the wire against an ingot to be cut into wafers while supplying a slurry for cutting to the grooved rollers and causing the wire to move, wherein a cooling rate of the ingot when a cutting depth is equal to or greater than 2 / 3 of a diameter is controlled to perform cutting by supplying a slurry for adjusting an ingot temperature to the ingot independently of the slurry for cutting, while controlling a supply temperature only in a period from the moment the cutting depth of the ingot reaches at least 2 / 3 of the diameter until the end of cutting. CN 1 02 233 620 A discloses a method for controlling a multi-wire cutting pressure. CN 1 03 085 180 A discloses a wire saw control system for operating a wire saw.CN 1 03 817 811 A discloses a multi-wire cutting method for a silicon rod. JP 2015 - 47 673 A discloses a multi-wire processing method and a multi-wire processing apparatus capable of easily and simply cutting a processing object industrially regardless of the distortion generation mechanism and capable of reducing the distortion of a cut-out plate-shaped body as much as possible. JP 2015 - 98 420 A discloses a silicon carbide ingot capable of suppressing distortion of a substrate when cut using a wire saw of a fixed abrasive grain system.JP 2016-140954 A discloses a multi-wire processing method and apparatus that can easily and simply cut a processing object in an industrial view and reduce the distortion of a cut-out sheet-like body as much as possible by suppressing thermal expansion deformation due to a temperature rise of a cutting processing part of a processing object cut by a saw wire. JP H09-225932 A discloses temperature control of working fluid for a wire saw and an apparatus therefor. DE 11 2018 001 068 T5 discloses a method for cutting an ingot with a wire saw and slurry, in which the temperature of the cooling water in each wire guide inside the ingot, the temperature of the cooling water in the wire casing, and the temperature of the slurry are measured and controlled. SUMMARY

[0005] In view of this, embodiments of the present disclosure aim to provide a processing method and system for reducing the curvature of nitrogen-doped wafers that the nitrogen-doped crystal ingot can cut to obtain wafers of high flatness and uniformity.

[0006] The technical solution of the embodiments of the present disclosure is implemented as follows.

[0007] In a first aspect, an embodiment of the present disclosure provides a processing method for reducing the curvature of a nitrogen-doped wafer, comprising: Dividing a nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed according to the distribution of nitrogen content, each ingot segment to be processed corresponding to a nitrogen content range; Determining a processing state corresponding to each crystal ingot segment to be processed according to the correspondences between nitrogen content ranges and processing states, wherein the processing state enables the corresponding crystal ingot segment to be processed to be prevented from curving during wire sawing; and Performing the cutting processing respectively on each crystal ingot segment to be processed using the processing state corresponding to each crystal ingot segment to be processed, thereby obtaining a wafer by cutting the nitrogen-doped crystal ingot to be cut. In a second aspect, an embodiment of the present disclosure provides a processing system for reducing the curvature of a nitrogen-doped wafer, comprising: a scheduling section, a determining section, and a processing section; wherein the dividing section is configured to divide a nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed according to the distribution of the nitrogen content, each ingot segment to be processed corresponding to a nitrogen content range; the determining section is configured to determine a processing state corresponding to each crystal ingot segment to be processed according to the correspondences between nitrogen content ranges and processing states, wherein the processing state enables the corresponding crystal ingot segment to be processed to be prevented from curving during wire sawing; and the processing section is configured to perform cutting processing on each crystal ingot segment to be processed using the processing state corresponding to each crystal ingot segment to be processed, thereby obtaining a wafer by cutting the nitrogen-doped crystal ingot to be cut.

[0008] According to the processing method and system for reducing the warpage of nitrogen-doped wafers in embodiments of the present disclosure, the nitrogen-doped crystal ingot to be cut is divided into different crystal ingot segments to be processed according to the nitrogen content ranges. After determining the processing conditions that can prevent the warpage phenomenon for each crystal ingot segment to be processed, the corresponding crystal ingot segments to be processed are cut according to the corresponding processing conditions, so that wafers with high flatness and uniformity are obtained and the likelihood of the warpage problem is reduced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the nitrogen content distribution of a nitrogen-doped monocrystalline silicon ingot according to an embodiment of the present disclosure; Fig. 2 is a schematic flow diagram of a processing method for reducing the curvature of nitrogen-doped wafers according to an embodiment of the present disclosure; Fig. 3 is a schematic view of a crystal ingot segment to be processed obtained by cutting a nitrogen-doped crystal ingot according to an embodiment of the present disclosure; Fig. 4 is a schematic diagram of a multi-wire sawing apparatus according to an embodiment of the present disclosure; Fig. 5 is a schematic diagram of an effect comparison according to an embodiment of the present disclosure; Fig. 6 is a schematic diagram of a processing system for reducing the warpage of nitrogen-doped wafers according to an embodiment of the present disclosure; and Fig.7 is another schematic diagram of a processing system for reducing the warpage of nitrogen-doped wafers according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0009] The technical solutions in the embodiments of the present disclosure will be described below clearly and completely with reference to the accompanying drawings in the embodiments of the present disclosure.

[0010] At the solid-liquid interface, the solubility of impurities in different phases varies, causing the concentration of impurities in materials to be distributed differently on both sides of the interface. This is the impurity segregation phenomenon, and the magnitude of the impurity segregation effect is usually described by the segregation coefficient. In the process of pulling monocrystalline silicon ingots using the Czochralski method, a solid-liquid interface is formed between the silicon melt and the monocrystalline silicon ingot. If nitrogen elements are considered as impurities, then by considering the influence of melt convection on the segregation of solutes, an effective segregation coefficient of impurity segregation can be obtained using the Burton approximation.The effective segregation coefficient is as shown in the following equation 1:. keffective=CsCl=k0k0+(1−k0)exp(−VDδ) where C s represents a concentration of the impurity in the solid phase; C l represents a concentration of the impurity within the melt; k0 represents an equilibrium segregation coefficient of the impurity, nitrogen is considered as an impurity in embodiments of the present disclosure, and the value is expressed as 7×10 -4 can be selected.

[0011] From the above formula, it can be seen that the effective segregation coefficient of nitrogen is usually very low. Therefore, in the process of pulling monocrystalline silicon ingots using the Czochralski method, nitrogen elements exhibit a segregation phenomenon along an axial direction of the crystal ingot during the pulling of the crystal ingot, resulting in an uneven nitrogen concentration along the axial direction of the entire crystal ingot. This usually manifests itself as in Fig.1, where the nitrogen content gradually decreases from a lower end of the crystal ingot to an upper end of the crystal ingot. Specifically, the nitrogen content at the lower end of the crystal ingot is significantly greater than that at the upper end of the crystal ingot. Since the nitrogen content is positively correlated with mechanical strength, the mechanical strength of different parts of the crystal ingot also varies with the change in nitrogen content based on the occurrence of the aforementioned segregation phenomenon. For example, the nitrogen content at a lower end of the crystal ingot is greater than that at an upper part of the crystal ingot, thus the mechanical strength of the lower end of the crystal ingot is also significantly greater than that of the upper end of the crystal ingot.Thus, when the entire nitrogen-doped monocrystalline silicon ingot is sawn with a wire saw or a multi-wire saw under the same processing conditions, the heat generated during the processing cannot be dissipated in time due to the high mechanical strength of the lower end of the crystal ingot and the insufficient feed rate of the cutting steel wire. At this time, the accumulated heat causes wafers cut from the lower end of the crystal ingot to warp more than wafers cut from the upper end of the crystal ingot.

[0012] Based on the above description, embodiments of the present disclosure aim to provide a processing scheme for reducing the curvature of a nitrogen-doped wafer. Taking into account the total nitrogen content of the nitrogen-doped monocrystalline silicon ingot, different wire saw processing states are used, thereby improving cutting performance, reducing the likelihood of the curvature problem, and obtaining wafers with high flatness and uniformity. Based on this, Fig. 2 with reference to Fig. 2 illustrates a processing method for reducing the curvature of nitrogen-doped wafers according to an embodiment of the present disclosure. The method may include:

[0013] S201: Dividing, according to the distribution of the nitrogen content of the nitrogen-doped crystal ingot to be cut, a nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed, each ingot segment to be processed corresponding to a nitrogen content range.

[0014] S202: Determining, according to correspondences between nitrogen content ranges and processing conditions, a processing condition corresponding to each crystal ingot segment to be processed, the processing condition enabling the corresponding crystal ingot segment to be processed to be prevented from curving during wire sawing;

[0015] S203: Using the processing state corresponding to each crystal ingot segment to be processed, perform the cutting processing on each crystal ingot segment to be processed, thereby obtaining a wafer by cutting the nitrogen-doped crystal ingot to be cut.

[0016] The technical solution developed in Fig. As shown in Figure 2, the nitrogen-doped crystal ingot to be cut is divided into different processing crystal ingot segments according to the nitrogen content ranges. After determining the processing conditions that can prevent the warping phenomenon for each processing crystal ingot segment, the corresponding processing crystal ingot segments are cut according to the corresponding processing conditions, thereby obtaining wafers with high flatness and uniformity and reducing the likelihood of the warping problem.

[0017] At the Fig. 2, in some possible implementations, before performing step S201, the method may further comprise: detecting the distribution of the nitrogen content of the nitrogen-doped crystal ingot to be cut.

[0018] In the above implementation, in some examples, detecting the distribution of the nitrogen content of the nitrogen-doped crystal ingot to be cut includes: Acquiring detection samples corresponding to a plurality of axial sample positions along an axial direction of the nitrogen-doped crystal ingot to be cut; Cooling each detection sample rapidly after removing thermal donors of each detection sample, and using a Fourier transform infrared spectrometer (FTIR) to detect a nitrogen content corresponding to each detection sample after cooling to obtain nitrogen contents of the plurality of axial sample positions that characterize the nitrogen content distribution of the nitrogen-doped crystal ingot to be cut.

[0019] It should be noted that the above implementation can obtain the nitrogen content distribution of the entire nitrogen-doped crystal ingot to be cut. As shown in Fig. 1, for example, by setting appropriate nitrogen content thresholds, the nitrogen content distribution can be divided into three sections, which are Fig.1 are marked as I, II, and III. Section I corresponds to an upper end part of the entire nitrogen-doped crystal ingot to be cut; Section III corresponds to a lower end part of the entire nitrogen-doped crystal ingot to be cut; and Section II corresponds to a middle part of the entire nitrogen-doped crystal ingot to be cut. According to the marked nitrogen distribution areas, the nitrogen-doped crystal ingot to be cut can be divided into three parts. In particular, as shown in Fig.3, the nitrogen-doped crystal ingot to be cut is cut into three crystal ingot segments to be processed. Since each crystal ingot segment to be processed corresponds to a nitrogen content distribution region, in the present embodiment, identifiers of different crystal ingot segments to be processed can be labeled consistently with the identifiers of the corresponding nitrogen content distribution regions, that is, labeled as I, II, and III. For the three crystal ingot segments to be processed shown in Fig.3, the processed crystal ingot segment I, which corresponds to the upper end part of the nitrogen-doped crystal ingot to be cut, has the lower nitrogen content. The processed crystal ingot segment III, which corresponds to the lower end part of the nitrogen-doped crystal ingot to be cut, has the higher nitrogen content. The processed crystal ingot segment II, which corresponds to the middle part of the nitrogen-doped crystal ingot to be cut, has a nitrogen content between the nitrogen content of the processed crystal ingot segment I and the nitrogen content of the processed crystal ingot segment III.

[0020] At the Fig.2 include, in some possible implementations, determining, according to correspondences between nitrogen content ranges and processing states, the processing state corresponding to each crystal ingot segment to be processed: Capturing temperature values ​​at a plurality of specified radial positions during the wire sawing process for each crystal ingot segment to be processed; Determining, based on the temperature values ​​at the same radial positions, temperature differences between each crystal ingot segment to be processed; Determining, based on the temperature difference between each crystal ingot segment to be processed, steel wire feed amounts corresponding to each crystal ingot segment to be processed such that a processing temperature of the crystal ingot segments to be processed, excluding those located at an upper end of the nitrogen-doped crystal ingot to be cut, is consistent with a processing temperature of the crystal ingot segments to be processed located at an upper end of the nitrogen-doped crystal ingot to be cut.

[0021] In the aforementioned implementations, in some examples, of the crystal ingot segments to be processed, the steel wire feed amount corresponding to the crystal ingot segment to be processed that is located at the top end of the nitrogen-doped crystal ingot to be cut is less than the steel wire feed amounts corresponding to the crystal ingot segments to be processed except those located at the top end of the nitrogen-doped crystal ingot to be cut.

[0022] In the above mentioned implementations and their examples, in particular the three above mentioned crystal ingot segments to be processed, which are in Fig.3 are taken as an example. Since the nitrogen contents of different crystal ingot segments to be processed are inconsistent with respect to the positive correlation between nitrogen content and mechanical strength, it is known that the mechanical strength of crystal ingot segment I to be processed is lower than the mechanical strength of crystal ingot segment II to be processed, and the mechanical strength of crystal ingot segment III to be processed is the highest among the three crystal ingot segments to be processed.In the process of wire sawing or multi-wire sawing, when all three crystal ingot segments to be processed are cut under the processing conditions suitable for the crystal ingot segment I to be processed, excessive heat is generated due to the excessive mechanical strength of the crystal ingot segments II and III to be processed, causing the processing temperature to rise, forming a temperature difference with the processing temperature of the crystal ingot segment I to be processed, thereby increasing the likelihood of the curvature problem of the silicon wafers cut from the crystal ingot segments II and III to be processed. To avoid the occurrence of curvature, it is necessary to compensate for the temperature difference.Specifically, for the crystal ingot segments I, II, and III to be processed, positions of 330 mm, 1060 mm, and 1730 mm are selected along an axial direction from the top end of the nitrogen-doped crystal ingot to be cut, which correspond to the radial temperature detection positions of the crystal ingot segments I, II, and III to be processed, respectively. Specifically, the temperature of the cutting process can be detected at the radial positions of 76 mm, 151.35 mm, and 259.11 mm, respectively. As shown in . Fig.As shown in Figure 3, the temperature values ​​detected at the radial positions of 76 mm, 151.35 mm, and 259.11 mm of the crystal ingot segment to be processed I are a, b, and c, respectively; the temperature values ​​detected at the radial positions of 76 mm, 151.35 mm, and 259.11 mm of the crystal ingot segment to be processed II are a', b', and c', respectively; and the temperature values ​​detected at the radial positions of 76 mm, 151.35 mm, and 259.11 mm of the crystal ingot segment to be processed III are a'', b'', and c''. Subsequently, based on the previously detected temperature values, the temperature differences between different crystal ingot segments to be processed are calculated. In the present embodiment, the temperature difference between the crystal ingot segments I and II to be processed and the temperature difference between the crystal ingot segments II and III to be processed are to be calculated.The specific calculation results of the temperature differences are shown in Table 1:. Table 1 Radial position of crystal ingot (mm) Axial position of the crystal ingot (mm) 330 1060 1730 ΔT1 ΔT2 76 Recording position a a' a'' 0,5 0,1 Temperature (°C) 26,2 26,7 26,8 151,35 Recording position b b' b'' 0,5 0,3 Temperature (°C) 30,6 31,1 31,4 259,11 Recording position c c' c'' 0,4 0,4 Temperature (°C) 27,1 27,5 27,9

[0023] Where ΔT1 represents the temperature difference between the crystal ingot segments I and II to be processed; ΔT2 represents the temperature difference between the crystal ingot segments II and III to be processed.

[0024] From the data obtained in Table 1, in order to compensate for the temperature difference during processing, it is necessary to adjust the processing conditions of each crystal ingot segment to be processed so that the processing temperature of the crystal ingot segments II and III to be processed is consistent with the processing temperature of the crystal ingot segment I to be processed, in order to avoid the warping of the silicon wafer due to high mechanical strength and excessive heat generated during cutting. In embodiments of the present disclosure, the processing conditions may optionally be, in particular, the steel wire feed amount during processing. By combining Fig.3 and the above, as the nitrogen content of the crystal ingot segments I, II, and III to be processed gradually increases, the mechanical strength also increases accordingly. Then, in order to maintain the processing temperature during the cutting of the crystal ingot segment I to be processed at the processing temperature during the cutting process, embodiments of the present disclosure maintain the processing temperature by increasing the steel wire feed rate of the crystal ingot segments II and III to be processed. Specifically, the steel wire feed rate is characterized by a feed ratio of the steel wire, and the steel wire feed rates corresponding to the crystal ingot segments I, II, and III to be processed are shown in Table 2: Table 2 Identification of crystal ingot segment to be processed I II III Steel wire feed rate 180 % 200 % 220 %

[0025] Regarding the aforementioned concept of the steel wire feed amount, specifically, in the present embodiment, within one processing cycle time, if the setting of a wire output amount is x, a wire take-up amount is y, then the steel wire feed amount is xy, and the feed ratio is considered 100%. Within the same cycle time, if the setting of the wire output amount is 2x-y, the wire take-up amount is y, then the steel wire output amount is 2*(xy), and the feed ratio is 200%; if the setting of the wire output amount is 3x-2y, the wire take-up amount is y, then the steel wire feed amount is 3*(xy), and the feed ratio is 300%, and so on.

[0026] According to the above description, after obtaining the steel wire feed amounts corresponding to the crystal ingot segments I, II and III to be processed shown in Table 2, the Fig.4 shown multi-wire sawing device is taken as an example. In Fig. 4, the device comprises a wire output spindle 1, a wire take-up spindle 2, a guide wheel 3, a crystal ingot feed table 5 and a steel wire 6. In the cutting process of the nitrogen-doped crystal ingot 4 to be cut using the Fig. 4, when cutting the crystal ingot segment I to be processed with a low hardness, the steel wire feed rate of the wire output spindle 1 is controlled to a smaller value, such as 180% in Table 2. After the processing of the crystal ingot segment I to be processed is completed, the crystal ingot segment II with medium hardness is fed onto the crystal ingot feed table 5 in Fig.4. When cutting the crystal ingot segment II to be processed, the steel wire feed rate of the wire output spindle 1 is controlled to be greater than the steel wire feed rate when cutting the crystal ingot segment I to be processed, such as 200% in Table 2. After the processing of the crystal ingot segment II to be processed is completed, the crystal ingot segment III to be processed with the greatest hardness is fed onto the crystal ingot feed table 5 in Fig.4. When cutting the crystal ingot segment III to be processed with a higher hardness, the steel wire feed rate of the wire output spindle 1 is controlled to be the largest, such as 220% in Table 2. It is understood that at this time, the feed rate of new steel wire is large, which can timely dissipate the heat generated by the mechanical cutting processing and avoid severe curvature of the silicon wafer due to high temperature, thereby greatly reducing the probability of temperature difference.

[0027] When comparing the wafer curvature quality obtained by cutting after adjusting the steel wire feed amount by the above technical solution and its implementations and examples, and the wafer curvature quality obtained by cutting using the same processing conditions without adjusting the steel wire feed amount in the current conventional scheme as in Fig. 5, the horizontal axis in the figure represents a position of the nitrogen-doped crystal ingot to be cut, and the vertical axis represents a curvature value of the wafer in micrometers (µm). The deep black dots in Fig. 5 represent the curvature after adjusting the steel wire feed rate. The gray colored points represent the curvature without adjusting the steel wire feed rate. As can be seen from Fig.5, wafers with higher and more uniform flatness can be obtained compared to the conventional scheme, and the probability of the warpage problem is reduced by the technical solution of the embodiments of the present disclosure.

[0028] With reference to Fig. 6 shows Fig. 6, based on the same inventive concept as the above technical solution, a processing system 60 for reducing the curvature of a nitrogen-doped wafer according to an embodiment of the present disclosure is shown. The processing system 60 includes a scheduling section 601, a determining section 602, and a processing section 603.

[0029] The dividing section 601 is configured to divide a nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed according to the distribution of the nitrogen content, wherein each ingot segment to be processed corresponds to a nitrogen content range.

[0030] The determining section 602 is configured to determine, according to correspondences between nitrogen content ranges and processing conditions, a processing condition corresponding to each crystal ingot segment to be processed, the processing condition enabling the corresponding crystal ingot segment to be processed to be prevented from curving during wire sawing.

[0031] The processing section 603 is configured to perform cutting processing on each crystal ingot segment to be processed, using the processing state corresponding to each crystal ingot segment to be processed, thereby obtaining a wafer by cutting the nitrogen-doped crystal ingot to be cut.

[0032] In particular, the processing section 603 may be the multi-wire sawing device which is Fig. 4, which is not further described in the embodiment of the present disclosure.

[0033] In some examples, as in Fig. 7, the determining section 602 includes a detecting device 6021 and a data processing device 6022.

[0034] The detection device 6021 is configured to separately detect temperature values ​​at a plurality of excluding radial positions for each crystal ingot segment to be processed during the wire sawing process.

[0035] The data processing device 6022 is configured to determine temperature differences between different crystal ingot segments to be processed based on the temperature values ​​at the same radial position of different crystal ingot segments to be processed, and based on the temperature difference between different crystal ingot segments to be processed, to determine steel wire feed amounts corresponding to each crystal ingot segment to be processed, so that a processing temperature of the crystal ingot segments to be processed excluding those located at an upper end of the nitrogen-doped crystal ingot to be cut is consistent with a processing temperature of the crystal ingot segments to be processed located at an upper end of the nitrogen-doped crystal ingot to be cut.

[0036] In some examples, the dividing section 601 is configured to cut a nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed according to the distribution of the nitrogen content.

[0037] In some examples, the processing system 60 further includes, as in Fig.7, a detection section 604 configured to detect the distribution of the nitrogen-doped crystal ingot to be cut.

[0038] It is understood that in the embodiment, a "portion" may be a portion of a circuit, a portion of a processor, a portion of a program or software, and the like, but of course may also be a unit, and may also be modular and non-modular.

[0039] Furthermore, various components in the embodiment may be integrated into a processing unit, each unit may also exist independently, and two or more units may also be integrated into one unit. The integrated unit may be implemented in hardware form and may also be implemented in the form of a software functional module.

[0040] When implemented in the form of a software functional module and not sold or used as an independent product, the integrated unit may be stored in a computer-readable storage medium. Based on such an understanding, the essence of the technical solution of the present disclosure, or the part that contributes to the prior art, or the part of the technical solution may be embodied in the form of a software product. The computer software product is stored in a storage medium and comprises various instructions that enable a computing device (which may be a personal computer, a server, or a network device, etc.) or a processor to perform all or parts of the steps of the methods described in various embodiments of the present disclosure.The storage medium includes various media capable of storing program codes, such as a U disk, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0041] Therefore, one embodiment of the present disclosure provides a computer storage medium including a processing program for reducing the curvature of a nitrogen-doped wafer stored thereon. The processing program for reducing the curvature of a nitrogen-doped wafer is executed by at least one processor to perform the method for reducing the curvature of a nitrogen-doped wafer in the aforementioned technical solutions.

[0042] It is understood that the schematic technical solution of the aforementioned processing system 60 for reducing the curvature of a nitrogen-doped wafer has the same concept as the technical solution of the aforementioned processing method for reducing the curvature of a nitrogen-doped wafer. Therefore, detailed contents of the processing system 60 for reducing the curvature of a nitrogen-doped wafer that are not described in detail may refer to the description of the technical solution of the aforementioned processing method for reducing the curvature of a nitrogen-doped wafer and are not described again in this document.

[0043] It should be noted that the technical solutions described in the embodiments of the present disclosure can be arbitrarily combined without causing conflicts.

[0044] The foregoing is only a specific implementation of the disclosure, but the scope of the present disclosure is not limited thereto. A person skilled in the art may make various variations under the teachings of this application without departing from the spirit of this application and the scope of the claims, and such variations are all within the scope of this application. Therefore, the scope of the present disclosure should be based on the scope of the mentioned claims.

Claims

[1] A processing method for reducing the curvature of a nitrogen-doped wafer, comprising: Dividing (S201) a nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed according to a distribution of the nitrogen content of the nitrogen-doped crystal ingot to be cut, each ingot segment to be processed corresponding to a nitrogen content range; Determining (S202) a processing state corresponding to each crystal ingot segment to be processed according to the correspondences between nitrogen content ranges and processing states, the processing state enabling the corresponding crystal ingot segment to be processed to be prevented from bending during wire sawing; and Performing (S203) the cutting processing on each crystal ingot segment to be processed using the processing state corresponding to each crystal ingot segment to be processed, thereby obtaining a wafer by cutting the nitrogen-doped crystal ingot to be cut; wherein determining (S202) a processing state corresponding to each crystal ingot segment to be processed according to the correspondences between nitrogen content ranges and processing states comprises: Capturing temperature values ​​at a plurality of specified radial positions during the wire sawing process for each crystal ingot segment to be processed; Determining temperature differences between the plurality of crystal ingot segments to be processed based on the temperature values ​​at the same radial positions of the plurality of crystal ingot segments to be processed; Determining steel wire feed amounts corresponding to each crystal ingot segment to be processed based on the temperature differences between the plurality of crystal ingot segments to be processed such that a processing temperature of crystal ingot segments to be processed, excluding the crystal ingot segment to be processed at an upper end of the nitrogen-doped crystal ingot to be cut, is consistent with a processing temperature of the crystal ingot segment to be processed at the upper end of the nitrogen-doped crystal ingot to be cut. [2] The processing method according to claim 1, wherein, in each crystal ingot segment to be processed, a steel wire feed amount corresponding to the crystal ingot segment to be processed at the top end of the nitrogen-doped crystal ingot to be cut is smaller than the steel wire feed amounts corresponding to the crystal ingot segments to be processed excluding the crystal ingot segment to be processed at the top end of the nitrogen-doped crystal ingot to be cut. [3] The processing method according to claim 1, wherein dividing (S201) a nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed according to the distribution of the nitrogen content comprises: Cutting the nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed according to the distribution of nitrogen content. [4] The processing method according to claim 1, wherein the method further comprises: Detecting the nitrogen content distribution of the nitrogen-doped crystal ingot to be cut. [5] The processing method according to claim 4, wherein detecting the distribution of the nitrogen content of the nitrogen-doped crystal ingot to be cut comprises: Acquiring detection samples corresponding to a plurality of axial sample positions along an axial direction of the nitrogen-doped crystal ingot to be cut; Cooling each detection sample rapidly after removing thermal donors of each detection sample, and using a Fourier transform infrared spectrometer to detect a nitrogen content corresponding to each detection sample after cooling, thereby obtaining nitrogen contents of the plurality of axial sample positions that characterize the nitrogen content distribution of the nitrogen-doped crystal ingot to be cut. [6] A processing system (60) for reducing the curvature of a nitrogen-doped wafer using the processing method for reducing the curvature of a nitrogen-doped wafer according to claim 1, the processing system comprising: a scheduling section (601), a determining section (602), and a processing section (603); wherein the dividing section (601) is configured to divide a nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed according to the distribution of the nitrogen content of the nitrogen-doped crystal ingot to be cut, each ingot segment to be processed corresponding to a nitrogen content range; the determining section (602) is configured to determine a processing state corresponding to each crystal ingot segment to be processed according to the correspondences between nitrogen content ranges and processing states, the processing state enabling the corresponding crystal ingot segment to be processed to be prevented from curving during wire sawing; and the processing section (603) is configured to perform cutting processing on each crystal ingot segment to be processed using the processing state corresponding to each crystal ingot segment to be processed, thereby obtaining a wafer by cutting the nitrogen-doped crystal ingot to be cut; wherein the determination section (602) comprises a detection device (6021) and a data processing device (6022); the detection device (6021) is configured to detect temperature values ​​at a plurality of predetermined radial positions for each crystal ingot segment to be processed during the wire sawing process; the data processing device (6022) is configured to determine temperature differences between the plurality of crystal ingot segments to be processed based on the temperature values ​​at the same radial positions of the plurality of crystal ingot segments to be processed, and Determining steel wire feed amounts corresponding to each crystal ingot segment to be processed based on the temperature differences between the plurality of crystal ingot segments to be processed such that a processing temperature of crystal ingot segments to be processed, excluding the crystal ingot segment to be processed at an upper end of the nitrogen-doped crystal ingot to be cut, is consistent with a processing temperature of the crystal ingot segment to be processed at the upper end of the nitrogen-doped crystal ingot to be cut. [7] The processing system (60) according to claim 6, wherein the dividing section (601) is configured to cut the nitrogen-doped crystal ingot to be cut into a plurality of crystal ingot segments to be processed according to the distribution of the nitrogen content. [8] The processing system (60) according to claim 6, further comprising a detection section (604) configured to detect the distribution of the nitrogen content of the nitrogen-doped crystal ingot to be cut.

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