Method for evaluating dislocation ratio value of silicon block end face, method for removing dislocation ratio value, device and medium

Abstract

The present invention discloses a method for evaluating and removing dislocation ratios of silicon block end faces, a method for evaluating and removing dislocation ratios, an evaluation device, and a storage medium. The evaluation method includes measuring a photoluminescence image of the silicon block end face; determining and obtaining a first dislocation region, where the first dislocation region is a region in the photoluminescence image having a grayscale value less than a grayscale value threshold; determining and obtaining a misjudged dislocation region within the first dislocation region; wherein the misjudged dislocation region includes a line mark misjudged dislocation region and / or a dark area misjudged dislocation region; calculating the difference between the area of ​​the first dislocation region and the area of ​​the misjudged dislocation region; and calculating the percentage of the difference to the area of ​​the silicon block end face to obtain the dislocation ratio value of the silicon block end face. The present invention eliminates misjudgments caused by line marks and dark areas, effectively improving the accuracy of dislocation ratio evaluation, avoiding the loss of cast single crystal silicon blocks due to misjudgments, and ensuring the yield of cast single crystal products.

Description

Technical Field

[0001] The present invention relates to the technical field of cast single crystal silicon preparation, and in particular to an evaluation method, a removal method, an evaluation device and a storage medium for a dislocation ratio value of a silicon block end face. Background Art

[0002] Cast single-crystal silicon ingots contain numerous dislocations, particularly those at the end faces, which affect the photoelectric conversion efficiency of silicon wafers. To ensure the quality of subsequent silicon wafers, existing techniques require precise calculation of the dislocation ratio at the end faces of the silicon ingot and, based on this ratio, calculate the required length of the silicon ingot head to be removed.

[0003] Typically, the method for removing a silicon block's head involves using a photoluminescence tester to obtain a photoluminescence image of the block's end face. The dislocation value is then determined based on the grayscale values ​​of each area in the image. The dislocation ratio of the silicon block's end face is then determined based on the target dislocation ratio. However, in the actual dislocation measurement process, the precision of the cutting equipment limits the production of areas with low grayscale values, which can affect the dislocation calculation results and reduce the accuracy of the final dislocation assessment for the silicon block's end face. Summary of the Invention

[0004] The present invention aims to provide an evaluation method, device, medium, equipment and cutting method for providing a dislocation ratio value of a silicon block end face.

[0005] A first aspect of the present invention provides a method for evaluating the dislocation ratio value of a silicon block end face, which is applicable to casting a single crystal silicon block and comprises:

[0006] Measure the photoluminescence image of the silicon block end face;

[0007] Determine and obtain a first dislocation region, where the first dislocation region is a region in the photoluminescence image where the grayscale value is less than a grayscale value threshold;

[0008] Determine and obtain the misjudged dislocation region of the first dislocation region; wherein the misjudged dislocation region includes a line mark misjudged dislocation region and / or a dark misjudged dislocation region;

[0009] Calculating a difference between an area of ​​the first dislocation region and an area of ​​the misjudged dislocation region;

[0010] The percentage of the difference and the area of ​​the end face of the silicon block is calculated to obtain a dislocation ratio value of the end face of the silicon block.

[0011] Optionally, the grayscale value threshold is 0-100RGB.

[0012] Furthermore, the method for determining the dislocation area by misjudging the line mark is:

[0013] measuring the length of the straight line or the minor arc curve in the first dislocation region;

[0014] When the length of the straight line or the minor arc curve in the first dislocation region is greater than a first preset length, the first dislocation region is determined to be a misjudged dislocation region.

[0015] Optionally, the first preset length is 30 mm.

[0016] Furthermore, the method for judging the dark misjudged dislocation region is:

[0017] Measure the block area in the first dislocation area, where the block area is an area formed by multiple straight lines or curves with a gray value less than the gray threshold, and the area of ​​the block area is greater than or equal to 1 cm 2 ; Wherein, when there is no closed-loop structure pattern in the block area, the first dislocation area is judged to be a misjudged dislocation area.

[0018] Among them, the closed-loop structure figure is an annular outer ring formed by a single or multiple straight lines or curves and a central area surrounded by the annular outer ring, the grayscale value of the annular outer ring is distributed within the grayscale value threshold range, and the grayscale value of the central area is greater than the grayscale value threshold.

[0019] In the first aspect of the present invention, the morphology of the graphics in the picture with a grayscale value less than a grayscale value threshold formed on the end face of the silicon wafer due to cutting and the formation mechanism of dislocations are analyzed and processed, thereby eliminating the misjudgment phenomenon caused by line marks and dark areas, effectively improving the accuracy of dislocation ratio assessment, and effectively improving the production capacity of silicon blocks without affecting the overall efficiency of the silicon blocks.

[0020] The second aspect of the present invention provides a method for removing the head of an ingot silicon block, which is suitable for casting single crystal silicon blocks. The dislocation ratio value of the silicon block head is evaluated using a method for evaluating the dislocation ratio value of the silicon block end face as provided in the first aspect of the present invention, and the removal length of the silicon block head is determined based on the dislocation ratio value.

[0021] The second aspect of the present invention provides a method for evaluating the dislocation ratio value of the end face of a silicon block provided by the first aspect of the present invention to evaluate the dislocation value and calculate the removal length of the silicon block head. The removal length of the head is reduced by at least 40 mm, effectively increasing the production capacity of the silicon block.

[0022] A third aspect of the present invention provides a device for evaluating the dislocation ratio value of a silicon block end face, suitable for casting a single crystal silicon block, the evaluation device comprising:

[0023] Image acquisition device; used to obtain photoluminescence images of the end face of the silicon block;

[0024] A first dislocation region determining device; used for determining and obtaining the first dislocation region in the photoluminescence image;

[0025] A misjudged dislocation region judging device; used for judging and obtaining the misjudged dislocation region within the first dislocation region;

[0026] A dislocation ratio value calculation device; used to calculate the difference between the area of ​​the first dislocation region and the area of ​​the misjudged dislocation region; and calculate the percentage of the difference to the area of ​​the silicon block end face to obtain the dislocation ratio value of the silicon block end face.

[0027] Furthermore, the misjudgment dislocation region judgment device includes a line mark misjudgment dislocation region judgment device and a dark misjudgment dislocation region judgment device.

[0028] The third aspect of the present invention provides a new device for evaluating the dislocation ratio value of the silicon block end face, which effectively improves the accuracy of the dislocation ratio value of the silicon block end face, and its accuracy is improved by at least 30%. The device is simple and convenient and can be effectively used for production guidance.

[0029] The fourth aspect of the present invention provides a computer-readable storage medium storing computer program instructions, characterized in that when the computer program instructions are executed by a processor, they implement the method for evaluating the dislocation ratio value of the end face of a silicon block provided in the first aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0031] Figure 1 A schematic flow chart of a method for evaluating the dislocation value of a silicon block end face according to the present invention is shown;

[0032] Figure 2 A schematic flow chart showing a method for determining a misjudgment of a line mark region as a dislocation region according to the present invention is shown;

[0033] Figure 3 A schematic flow chart showing a method for determining a misjudged dislocation region in a dark region according to the present invention is shown;

[0034] Figure 4 A schematic diagram of a module of a dislocation value evaluation device of the present invention is shown;

[0035] Figure 5 shows a closed-loop structure-like pattern in a photoluminescence image of a silicon block end surface in a specific embodiment of the present invention;

[0036] Figure 6shows a photoluminescence image of the end face of an original silicon block in a specific embodiment of the present invention;

[0037] Figure 7 Shown is the mark Figure 6 The first dislocation region and the misidentified dislocation region of the photoluminescence image;

[0038] Figure 8 Shown is the mark Figure 6 Photoluminescence picture of the true dislocation region.

[0039] Reference numerals:

[0040] 10-first dislocation region; 101-true dislocation region; 102-block area misjudged dislocation region; 103-straight line or minor arc curve misjudged dislocation region; 1021-dislocation formed by closed loop structure curve. DETAILED DESCRIPTION

[0041] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely illustrative and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0043] In the prior art, a photoluminescence tester mainly determines whether a region with a low grayscale value on the end face of a silicon block is a dislocation by grayscale value, and determines the removal length of the silicon block based on these dislocation results. Figure 6 The original photoluminescence image of the cast single crystal silicon block is shown in Figure 2. Figure 6As shown in the figure, there are many gray areas. The grayscale values ​​of the curves in these gray areas are significantly smaller than those in other areas. These areas will be judged as dislocations. However, in actual applications, due to the limitations of existing cutting technology, for example, due to the darker color and lower grayscale value at the line marks, they will be judged as dislocations. In addition, at the end of the silicon block, due to the weakened cutting ability and severe wear marks, silicon powder and water will be enriched in this area at high temperature, causing the area to be darker in color. In these areas, there will be a large number of areas with grayscale values ​​less than the grayscale value threshold, but these are not dislocations themselves, but are caused by cutting. As a result, the accuracy of dislocation judgment in the existing technology is low, and too much head and tail removal, especially too much removal of the head, affects the yield and increases costs.

[0044] For this reason, Figure 1 As shown, the first aspect of the present invention provides a method for evaluating the dislocation ratio value of a silicon block end face, which is applicable to casting a single crystal silicon block. The method comprises:

[0045] Measure the photoluminescence image of the silicon block end face;

[0046] In this step, a photoluminescence image of the silicon block end face is first measured; for example, a photoluminescence instrument from BT Imaging can be used to measure the photoluminescence image of the silicon block end face. This measurement method is prior art and will not be described in detail herein.

[0047] Determine and obtain a first dislocation region, where the first dislocation region is a region in the photoluminescence image where the grayscale value is less than a grayscale value threshold;

[0048] In this step, the grayscale value threshold may be an average reference value given by a photoluminescence instrument based on the overall grayscale value of the silicon block end face measured by the instrument; or an empirical value obtained by a person skilled in the art based on multiple measurement results of a testing instrument or measurement results of multiple silicon blocks in the same casting furnace;

[0049] Furthermore, the grayscale threshold value can be in the range of 0-100RGB; for example, it can be 0RGB, 10RGB, 15RGB, 25RGB, 30RGB, 50RGB, 60RGB, 80RGB, or 100RGB. In the computer field, white and black are generally divided into several levels according to a logarithmic relationship, which is called "grayscale level". The range is generally from 0 to 255, with white being 255 and black being 0. The smaller the grayscale value, the darker the color; conversely, the higher the grayscale value, the lighter the color. The grayscale value of the present invention is classified according to this value, which belongs to the prior art and will not be further described in detail.

[0050] The grayscale value of the scanned photoluminescence image of the entire silicon block end face is compared with a grayscale threshold to obtain an area with a grayscale value less than the threshold, i.e., the first dislocation area. The grayscale value comparison with the grayscale threshold can be performed using image processing software, such as Matlab, to automatically identify the grayscale value data in the original photoluminescence image and compare it with the grayscale threshold. When the grayscale value falls within the threshold range, the software assigns a color mark to the area, thereby obtaining the first dislocation area in the photoluminescence image. The present invention does not limit the specific method for obtaining the first dislocation area.

[0051] In a specific embodiment, Figure 7 As shown in the figure, the first dislocation area 10 is obtained by image processing software.

[0052] Determine and obtain the misjudged dislocation region of the first dislocation region; wherein the misjudged dislocation region includes a line mark misjudged dislocation region and / or a dark misjudged dislocation region;

[0053] In this step, after the first dislocation region is determined, it is necessary to determine the misjudged dislocation region. At this time, it is necessary to determine the misjudged dislocation region in the line mark region and / or the dark region.

[0054] like Figure 2 As shown in the figure, the method for judging the dislocation area by line trace misjudgment is:

[0055] measuring the length of the straight line or the minor arc curve in the first dislocation region;

[0056] When the length of the straight line or the minor arc curve in the first dislocation region is greater than a first preset length, the first dislocation region is determined to be a misjudged dislocation region.

[0057] In this step, the grayscale value of a straight line or a minor arc curve of a certain length in the first dislocation region is analyzed by image processing software;

[0058] When the continuous length of the straight line in the first dislocation area is greater than the first preset length, for example, the value of the first preset length is 30mm; then the area is determined to be a misjudged dislocation area; otherwise, it is a true dislocation. Since line marks are generally caused during the cutting process, the line marks are generally in the same direction and have a long length, while dislocations are caused by defects inside the crystal during crystal growth, and the dislocation growth direction is mainly perpendicular to the silicon wafer cutting direction, so its length will not be too long. The inventors have found through a large number of experiments that when the length of the straight line or the inferior arc curve of such grayscale value distribution at the grayscale value threshold exceeds 30mm, such straight line or inferior arc curve is caused by line marks, which will not affect the subsequent battery efficiency. Among them, the measurement of the first preset length of the straight line or inferior arc curve can be obtained using image processing software, and the present invention is not limited to this.

[0059] Furthermore, the method for determining whether a line mark is a misjudged dislocation region further includes determining that the first dislocation region is a misjudged dislocation region when the length of the straight line or the minor arc curve in the first dislocation region is greater than a first preset length and the width of the straight line or the minor arc curve is greater than a first preset width. This allows for more accurate confirmation of misjudged dislocation regions in line mark regions.

[0060] The first preset width is 2mm. For example, when the first preset length of the straight line or minor arc curve in the first dislocation region is 30mm, if the first preset width is greater than 2mm, the region is considered to be a misjudged dislocation region; otherwise, it is a true dislocation. Since the dislocations on the 100 growth plane of the cast single crystal silicon ingot are all closed-loop circular structures, during the growth process from the bottom of the silicon ingot upward, the closed-loop structures only increase in number and the individual areas increase, and there will be no very long and wide dislocation structures. Therefore, when there is a very long and wide straight line or curve in the first dislocation region, it is not caused by a dislocation. Therefore, by limiting the length and width, the misjudged dislocation region in the line mark area can be confirmed more accurately.

[0061] like Figure 3 As shown in the figure, the method for judging the misjudged dislocation area in the dark area is:

[0062] Measure the block area in the first dislocation area, where the block area is an area formed by multiple straight lines or curves with a gray value less than the gray threshold, and the area of ​​the block area is greater than or equal to 1 cm 2 Wherein, when there is no closed-loop structure pattern in the block area, the first dislocation area is determined to be a misjudged dislocation area. In this step, the grayscale value of the block area in the first dislocation area is analyzed by image processing software. When multiple straight lines or curves form a block area, where the curves can be composed of various inferior arcs, superior arcs, and multi-segment spline curves, the area formed by the block area as a whole is greater than or equal to 1 cm 2 When there is no closed-loop structure pattern in the block area, the block area is judged to be a misjudged dislocation area.

[0063] Among them, such as Figure 5 As shown, the closed-loop structure graph is an annular outer ring formed by a single or multiple straight lines or curves and a central area surrounded by the annular outer ring. The grayscale value of the annular outer ring is distributed within the grayscale value threshold range, and the grayscale value of the central area is greater than the grayscale value threshold.

[0064] Dark areas typically occur at the wire-out end of the cutting process. This is primarily due to the weakened cutting power during the silicon ingot's cutting process, which results in severe wear scarring. Silicon powder and water accumulate in this area at high temperatures, causing the dark area to appear dark. Therefore, dark areas typically consist of numerous wear scars, which are distributed continuously and cluster together to form large, dark areas. Dislocations are caused by internal defects in the crystal during growth, growing from the bottom of the ingot to the top, primarily as closed loops. Therefore, by studying the causes and mechanisms of dislocation formation, it is possible to distinguish dark areas from misidentified dislocations.

[0065] In a specific embodiment, Figure 6-8 As shown, Figure 6 is a photoluminescence image of the original silicon block end face in a specific embodiment; Figure 6 As shown in FIG, there are certain areas in the photoluminescence image where the grayscale value is less than the grayscale value threshold. Figure 6 The photoluminescence image is processed and the area with gray value less than 100RGB gray value threshold is obtained to form the following Figure 7 The photoluminescence image shown identifies the first dislocation area; Figure 7 As shown in the figure, there are various forms of dislocation graphics; including the first dislocation area 10 marked by a solid black frame and the first dislocation areas 10 marked by three different dashed black frames; it can be seen from the figure that the first dislocation area 10 marked by a solid black frame basically presents a closed loop structure, including an outer ring with a gray value less than the gray value area and a central area with a gray value greater than the gray value area; and the first dislocation area 10 marked by a dashed line contains two graphics, one is the area 103 formed by the minor arc curve and the block area 102 formed by multiple curves; wherein, the length of area 103 is greater than 30mm. The block area 102 is a whole piece, and there is no light-colored area with a gray value greater than the gray value threshold. Therefore, through further processing by the software, the determination method of the misjudgment dislocation area of ​​the present invention is used to Figure 7 The first dislocation region in the image was processed again to identify the true dislocation region and remove the photoluminescence images of the misjudged dislocation region. Figure 8 ,like Figure 8 As shown, Figure 7 The first dislocation region 10 within the dashed black frame is essentially excluded as a false dislocation region; the first dislocation region 10 within the solid black frame is essentially all true dislocations. This shows that the dislocation assessment method of the present invention can effectively increase the accuracy of dislocation assessment.

[0066] Calculating a difference between an area of ​​the first dislocation region and an area of ​​the misjudged dislocation region;

[0067] In this step, the first dislocation region and the misjudged dislocation region are obtained as described above. The area of ​​the first dislocation region and the area of ​​the misjudged dislocation region can be quickly obtained through image processing software. Since the misjudged dislocation region is not a real dislocation, the effective and real dislocation region can be obtained by eliminating the misjudged dislocation region in the first dislocation region.

[0068] The percentage of the difference and the area of ​​the end face of the silicon block is calculated to obtain a dislocation ratio value of the end face of the silicon block.

[0069] In this step, the difference is the area of ​​the dislocation region, and by dividing the difference by the area of ​​the entire silicon block end face, a dislocation ratio value with higher accuracy is obtained.

[0070] It can be seen from this that the present invention eliminates the misjudgment phenomenon caused by line marks and dark areas by studying the influence of cutting performance on the grayscale value of the silicon wafer end face, thereby effectively improving the accuracy of dislocation ratio evaluation and effectively improving the production capacity of silicon blocks without affecting the overall silicon block efficiency.

[0071] A second aspect of the present invention provides a method for removing the head of an ingot silicon block, suitable for casting single crystal silicon blocks. The method employs the method for evaluating the dislocation ratio of a silicon block end face provided in the first aspect of the present invention to assess the dislocation value, and then determines the length of the silicon block head to be removed based on the dislocation value. This method can improve the accuracy of silicon block head removal.

[0072] The third aspect of the present invention provides a device for evaluating the dislocation ratio value of a silicon block end face, which is suitable for casting a single crystal silicon block, such as Figure 4 As shown, the evaluation device includes:

[0073] Image acquisition device; used to obtain photoluminescence images of the silicon block end face; this device obtains the photoluminescence images of the silicon block through a photoluminescence tester and saves the images for subsequent analysis.

[0074] A first dislocation region determining device is provided; configured to determine and obtain a first dislocation region in the photoluminescence image. The device measures and obtains a photoluminescence image using a photoluminescence tester, stores the photoluminescence image, analyzes the grayscale values ​​in the photoluminescence image using image processing software, and identifies the first dislocation region by comparing the grayscale values ​​with a grayscale threshold. The first dislocation region determining device may be an image processing device, for example, utilizing Matlab software to automatically identify grayscale value data in an original photoluminescence image and compare the grayscale value with a grayscale threshold to obtain the first dislocation region in the photoluminescence image. The present invention does not limit the specific first dislocation region determining device.

[0075] A device for determining a misjudged dislocation region; used to determine and obtain a misjudged dislocation region within a first dislocation region; in this device, true dislocations and misjudged dislocations are determined by analyzing the morphological distribution of images of dislocations displayed in the first dislocation region.

[0076] Among them, the misjudgment dislocation area judgment device includes a line mark misjudgment dislocation area device and a dark misjudgment dislocation area device.

[0077] The line mark misjudgment dislocation area is to judge the first dislocation area distributed in the form of a straight line or a minor arc curve, and the dark misjudgment dislocation area is to judge the first dislocation area distributed in a blocky area.

[0078] Using image processing software, firstly, different forms of images formed by gray values ​​within the first dislocation region being less than a gray value threshold are identified;

[0079] When it is identified as a straight line or a minor arc curve, the length of the straight line or the minor arc curve is identified. When the length formed by the straight line or the minor arc curve is greater than a first preset length, for example, the value of the first preset length is 30 mm; it is determined that the area is a misjudged dislocation area; otherwise, it is a true dislocation.

[0080] Furthermore, the length and width of the straight line or the minor arc curve are identified. When the length formed by the straight line or the minor arc curve is greater than a first preset length, and when the width formed by the straight line or the minor arc curve is greater than a first preset width, for example, the value of the first preset length is 30 mm, and the value of the first preset width is 2 mm; then the area is determined to be a misjudged dislocation area; otherwise, it is a true dislocation.

[0081] When the area with gray value less than the gray value threshold is identified as a block area formed by multiple straight lines or curves, the area of ​​the block area is greater than or equal to 1cm 2 , and there is no closed-loop curve in the region, the dislocation region is judged to be a false dislocation region; otherwise, it is a true dislocation. The closed-loop structure can be calculated by the outer ring formed by the block region and the central region surrounded by the outer ring. When the grayscale value of the outer ring, i.e., the curve itself, is less than the grayscale value threshold, while the grayscale value of the central region is greater than the grayscale value region, the curve is considered to be a closed-loop structure and, therefore, a dislocation.

[0082] The misjudged dislocation area can be programmed through image processing software, such as Matlab software, by setting the length of a single straight line or a minor arc curve or the comparison of the length and width, or the area of ​​a block area formed by multiple straight lines or curves and the comparison of grayscale values, etc., so that the misjudged dislocation area can be determined.

[0083] A dislocation ratio calculation device is configured to calculate the difference between the area of ​​the first dislocation region and the area of ​​the misjudged dislocation region; and to calculate the percentage of the difference to the area of ​​the silicon block end face to obtain the dislocation ratio value of the silicon block end face. By obtaining the first dislocation region and the misjudged dislocation region, and through simple image processing, the area of ​​the first dislocation region, the area of ​​the misjudged dislocation region, and the area of ​​the entire silicon block end face can be obtained, thereby obtaining a more accurate dislocation ratio value. This device can be obtained using image processing software or computing software.

[0084] According to a fourth aspect of an embodiment of the present invention, a computer-readable storage medium is provided, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the method as described in any one of the first aspect of the embodiment of the present invention is implemented.

[0085] The following describes in detail a method for evaluating the dislocation ratio value of a silicon block end face according to the first aspect of the present invention using several specific embodiments. It should be understood that the following description is merely illustrative and does not constitute a specific limitation of the present invention.

[0086] Example 1

[0087] A cast single crystal silicon block was selected and the photoluminescence image of the end face of the block was measured using the BT imaging company's LIS photoluminescence tester. The area of ​​the first dislocation region was found to be 68.89 cm 2 The silicon block area of ​​the entire end face is 275.56cm 2 .

[0088] Graphics processing software was used to analyze and obtain the misjudged dislocation area of ​​the line traces and dark areas; and the area of ​​the misjudged dislocation area was calculated to be 22.04 cm 2 ;

[0089] Calculate the difference between the area of ​​the first dislocation region and the area of ​​the misjudged dislocation region;

[0090] The percentage of the difference and the end face area of ​​the silicon block is calculated to obtain the dislocation ratio value of the end face of the silicon block.

[0091] Determine the removal length of the silicon block according to the dislocation ratio value;

[0092] The silicon blocks after length removal are prepared using conventional battery technology to obtain the average efficiency of the silicon blocks.

[0093] Comparative Example 1

[0094] The difference between Comparative Example 1 and Example 1 is that the dislocation ratio value of the silicon block end face is obtained by using the percentage of the area of ​​the first dislocation region to the area of ​​the silicon block end face;

[0095] Determine the removal length of the silicon block according to the dislocation ratio value;

[0096] The silicon blocks after length removal are prepared using conventional battery technology to obtain the average efficiency of the silicon blocks.

[0097] Example 2

[0098] A cast single crystal silicon block was selected and the photoluminescence image of the end face of the block was measured using the BT imaging company's LIS photoluminescence tester. The area of ​​the first dislocation region was found to be 88.18 cm 2 The silicon block area of ​​the entire end face is 275.56cm 2 .

[0099] Use graphic processing software to analyze and obtain the line mark area and dark area of ​​the first dislocation area;

[0100] Graphics processing software was used to analyze and obtain the misjudged dislocation areas in the line trace area and the dark area; and the area of ​​the misjudged dislocation area was calculated to be 27.56 cm 2 ;

[0101] Calculate the difference between the area of ​​the first dislocation region and the area of ​​the misjudged dislocation region;

[0102] The percentage of the difference and the end face area of ​​the silicon block is calculated to obtain the dislocation ratio value of the end face of the silicon block.

[0103] Determine the removal length of the silicon block according to the dislocation ratio value;

[0104] The silicon blocks after length removal are prepared using conventional battery technology to obtain the average efficiency of the silicon blocks.

[0105] Comparative Example 2

[0106] The difference between Comparative Example 2 and Example 2 is that the percentage of the area of ​​the first dislocation region to the area of ​​the silicon block end face is used to obtain the dislocation ratio value of the silicon block end face;

[0107] Determine the removal length of the silicon block according to the dislocation ratio value;

[0108] The silicon blocks after length removal are prepared using conventional battery technology to obtain the average efficiency of the silicon blocks.

[0109] Example 3

[0110] A cast single crystal silicon block was selected and the photoluminescence image of the end face of the block was measured using the BT imaging company's LIS photoluminescence tester. The area of ​​the first dislocation region was found to be 110.22 cm 2 The silicon block area of ​​the entire end face is 275.56cm2 .

[0111] Use graphic processing software to analyze and obtain the line mark area and dark area of ​​the first dislocation area;

[0112] Graphics processing software was used to analyze and obtain the misjudged dislocation areas in the line trace area and the dark area; and the area of ​​the misjudged dislocation area was calculated to be 41.33 cm 2 ;

[0113] Calculate the difference between the area of ​​the first dislocation region and the area of ​​the misjudged dislocation region;

[0114] The percentage of the difference and the end face area of ​​the silicon block is calculated to obtain the dislocation ratio value of the end face of the silicon block.

[0115] Determine the removal length of the silicon block according to the dislocation ratio value;

[0116] The silicon blocks after length removal are prepared using conventional battery technology to obtain the average efficiency of the silicon blocks.

[0117] Comparative Example 3

[0118] The difference between Comparative Example 3 and Example 3 is that the percentage of the area of ​​the first dislocation region to the area of ​​the silicon block end face is used to obtain the dislocation ratio value of the silicon block end face;

[0119] Determine the removal length of the silicon block according to the dislocation ratio value;

[0120] The silicon blocks after length removal are prepared using conventional battery technology to obtain the average efficiency of the silicon blocks.

[0121] Evaluation criteria:

[0122] (1) % improvement in dislocation assessment accuracy = (dislocation ratio value of the evaluation method of the present invention - dislocation ratio value of the evaluation method of the prior art) / dislocation ratio value of the evaluation method of the prior art; wherein: dislocation ratio value of the evaluation method of the present invention = (area of ​​the first dislocation region - area of ​​the misjudged dislocation region) / end face area; dislocation ratio value of the evaluation method of the prior art = area of ​​the first dislocation region / end face area;

[0123] (2) the removal length of the silicon block; the removal length of the silicon block determined by the dislocation ratio value obtained by the dislocation evaluation method of the present invention or the prior art;

[0124] (3) Efficiency average: the efficiency average of the entire silicon block obtained using the dislocation evaluation method of the present invention or the prior art.

[0125] The following table shows the relevant test results of Examples 1 to 3 and Comparative Examples 1 to 3. As can be seen from the table, (1) compared with Comparative Examples 1 to 3, the accuracy of dislocation assessment in Examples 1 to 3 is improved by at least 30%; (2) compared with Comparative Examples 1 to 3, the removal length of the silicon block in Examples 1 to 3 is reduced by 40 mm. (3) compared with Comparative Examples 1 to 3, the yield of the silicon block in Examples 1 to 3 is improved by at least 12.5%. (4) the overall conversion efficiency of the silicon block in Examples 1 to 3 is close to that of Comparative Examples 1 to 3, which further proves the accuracy of the dislocation ratio evaluation method in the present invention.

[0126]

[0127]

[0128] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art can understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0129] Although the present invention has been described with reference to specific features and embodiments thereof, it will be apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the invention. It will be apparent that various modifications and variations may be made to the present invention by those skilled in the art without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such modifications and variations as fall within the scope of the claims of the present invention and their equivalents.

Claims

1. A method for evaluating the dislocation ratio value of a silicon block end face, characterized in that: Suitable for casting single crystal silicon blocks, the method comprises: Measure the photoluminescence image of the silicon block end face; Determine and obtain a first dislocation region, where the first dislocation region is a region in the photoluminescence image where the grayscale value is less than a grayscale value threshold; Determine and obtain a misjudged dislocation region of the first dislocation region; wherein the misjudged dislocation region is a line mark misjudged dislocation region and / or a dark misjudged dislocation region; Calculating a difference between an area of ​​the first dislocation region and an area of ​​the misjudged dislocation region; Calculating the percentage of the difference and the area of ​​the end face of the silicon block to obtain a dislocation ratio value of the end face of the silicon block; The method for determining the dislocation area by misjudging the line trace is as follows: measuring the length of the straight line or the minor arc curve in the first dislocation region; When the length of the straight line or the minor arc curve in the first dislocation region is greater than a first preset length, the first dislocation region is determined to be a misjudged dislocation region; The method for judging the dark misjudged dislocation region is as follows: Measure the block area in the first dislocation area, where the block area is an area formed by multiple straight lines or curves with a gray value less than the gray threshold, and the area of ​​the block area is greater than or equal to 1 cm 2 ; Wherein, when there is no closed-loop structure figure in the block area, the first dislocation area is judged to be a misjudged dislocation area; the closed-loop structure figure is an annular outer ring formed by a single or multiple straight lines or curves and a central area surrounded by the annular outer ring, the grayscale value of the annular outer ring is distributed within the grayscale value threshold range, and the grayscale value of the central area is greater than the grayscale value threshold.

2. The method for evaluating the dislocation ratio value according to claim 1, wherein: The grayscale value threshold is 0-100RGB.

3. The method for evaluating the dislocation ratio value according to claim 1, wherein: The first preset length is 30 mm.

4. A method for removing the head of an ingot silicon block, characterized in that: The method is suitable for casting a single crystal silicon block, wherein the dislocation ratio value of the silicon block head is evaluated by the evaluation method according to any one of claims 1 to 3, and the removal length of the silicon block head is determined according to the dislocation ratio value.

5. An evaluation device used in the method for evaluating the dislocation ratio value of a silicon block end face according to any one of claims 1 to 3, characterized in that: Suitable for casting single crystal silicon blocks, the evaluation device comprises: Image acquisition device; used to obtain photoluminescence images of the end face of the silicon block; A first dislocation region determining device; used for determining and obtaining the first dislocation region in the photoluminescence image; Misjudged dislocation region judging device; used to judge and obtain the misjudged dislocation region in the first dislocation region; the misjudged dislocation region judging device is a line mark misjudged dislocation region device and a dark misjudged dislocation region device; A dislocation ratio value calculation device; used to calculate the difference between the area of ​​the first dislocation region and the area of ​​the misjudged dislocation region; and calculate the percentage of the difference to the area of ​​the silicon block end face to obtain the dislocation ratio value of the silicon block end face.

6. A computer-readable storage medium storing computer program instructions, characterized in that: The computer program instructions implement the method according to any one of claims 1 to 3 when executed by a processor.

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