A twin defect detection method, system and computer storage medium

Abstract

The present disclosure discloses a twin defect detection method, system and computer storage medium, the detection method comprising: sampling a first sample silicon wafer and a second sample silicon wafer from a single crystal silicon rod to be tested; when the crystal directions of a first line defect on the first sample silicon wafer and a second line defect on the second sample silicon wafer are both parallel to <110> When the single crystal silicon rod to be tested is in the same crystal direction, a first length corresponding to the first line defect and a second length corresponding to the second line defect are measured respectively; based on a first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length and the second length, it is determined whether there is a twin defect inside the single crystal silicon rod to be tested.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the field of semiconductor manufacturing technology, and in particular, to a twin defect detection method, system, and computer storage medium. Background Art

[0002] At present, silicon wafers are the most widely used device substrates in the field of electronic information. Usually, silicon wafers are obtained by cutting, grinding, etching and polishing the single crystal silicon rods prepared by the Czochralski method. Specifically, the Czochralski method is to melt the polycrystalline silicon raw material and immerse the seed crystals with a specific crystal orientation into the polycrystalline silicon melt to prepare the single crystal silicon rods. In the preparation process of the single crystal silicon rod, the silicon atoms will be arranged downward according to the crystal orientation arrangement rule of the seed crystal, so as to increase the length until the single crystal silicon rod is completed.

[0003] However, during the preparation of single crystal silicon rods, due to the influence of various factors, different defects will be generated inside the single crystal silicon rod. The defects of single crystal silicon rods are divided into point defects, line defects and surface defects. Among them, twin defects are surface defects that often occur in the preparation of single crystal silicon rods. Twin defects are usually caused by the fact that the crystal arrangement of silicon atoms is affected by the stress introduced by impurities during the crystal growth process, so that the crystal arrangement of silicon atoms deviates from the crystal arrangement direction in the seed crystal, and then the crystal direction in the single crystal silicon rod is twisted. During the preparation of single crystal silicon rods, if the twin defects continue to extend and grow along the new growth direction, the process personnel will find that the outer edge of the single crystal silicon rod will disappear or shift by a certain angle, resulting in the single crystal silicon rod with the above-mentioned twin defects being remelted and re-prepared, reducing production efficiency. In addition, since it is difficult to detect twin defects inside single crystal silicon rods in the early stage, the above twin defects can only be detected through nano morphology testing, differential interference contrast microscope (DIC) testing, stress testing or surface particle testing after the final polishing process, resulting in a waste of production capacity. Summary of the invention

[0004] In view of this, the embodiments of the present disclosure hope to provide a twin defect detection method, system and computer storage medium; which can accurately determine the twin defects inside the single crystal silicon rod, improve production efficiency and reduce waste of production capacity.

[0005] The technical solution of the embodiment of the present disclosure is implemented as follows:

[0006] In a first aspect, an embodiment of the present disclosure provides a method for detecting twin defects, the method comprising:

[0007] Sampling the single crystal silicon rod to be tested to obtain a first sample silicon wafer and a second sample silicon wafer;

[0008] When the crystal directions of the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer are both parallel to <110> When the first line defect has a first length corresponding to the first line defect and the second line defect has a second length corresponding to the second line defect, the first length is smaller than the second length.

[0009] Based on a first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length, and the second length, it is determined whether there is a twin defect inside the single crystal silicon rod to be tested.

[0010] In a second aspect, an embodiment of the present disclosure provides a twin defect detection system, the detection system comprising: a sampling unit, a measuring unit and a determining unit; wherein:

[0011] The sampling part is used to sample the single crystal silicon rod to be tested to obtain a first sample silicon wafer and a second sample silicon wafer;

[0012] The measuring unit is configured to measure the first twin line on the first sample silicon wafer and the second twin line on the second sample silicon wafer when the crystal directions are both parallel to <110> When the first twin line and the second twin line are aligned in the same direction, a first length corresponding to the first twin line and a second length corresponding to the second twin line are measured respectively; wherein the first length is smaller than the second length;

[0013] The determination unit is configured to determine whether there is a twin defect inside the single crystal silicon rod to be tested based on a first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length, and the second length.

[0014] In a third aspect, an embodiment of the present disclosure provides a twin defect detection system, the detection system comprising a band saw or a wire cutting machine, and a data processing subsystem; wherein,

[0015] The band saw or the wire saw is used to sample the single crystal silicon rod to be tested to obtain a first sample silicon wafer and a second sample silicon wafer;

[0016] The data processing subsystem is configured as follows:

[0017] When the crystal directions of the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer are both parallel to <110> When the first line defect has a first length corresponding to the first line defect and the second line defect has a second length corresponding to the second line defect, the first length is smaller than the second length.

[0018] Based on a first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length, and the second length, it is determined whether there is a twin defect inside the single crystal silicon rod to be tested.

[0019] In a fourth aspect, an embodiment of the present disclosure provides a computer storage medium storing a twin defect detection program, wherein the twin defect detection program is executed by at least one processor to perform the steps of the twin defect detection method described in the first aspect.

[0020] The embodiment of the present disclosure provides a twin defect detection method, device, equipment and computer storage medium; a first sample silicon wafer and a second sample silicon wafer are obtained by sampling from a single crystal silicon rod to be tested; when the crystal directions of the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer are both parallel to <110> When measuring the crystal direction, the first length corresponding to the first line defect and the second length corresponding to the second line defect are measured respectively, and then according to the first distance, the first length and the second length of the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, it can be determined whether there is a twin defect inside the single crystal silicon rod to be tested. Through the technical solution provided by the embodiment of the present disclosure, it is possible to accurately determine whether there is a twin defect inside the single crystal silicon rod, which is different from the naked eye judgment of the process personnel, reduces the judgment error, and not only improves the production efficiency but also reduces the waste of production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the arrangement of silicon atoms in a single crystal silicon rod with twin defects provided in an embodiment of the present disclosure;

[0022] Figure 2 A twin defect of the (111) crystal plane in a single crystal silicon rod provided by an embodiment of the present disclosure;

[0023] Figure 3 A schematic flow chart of a twin defect detection method provided in an embodiment of the present disclosure;

[0024] Figure 4 The embodiments of the present disclosure provide <110> Schematic diagram of crystal orientation;

[0025] Figure 5 A schematic diagram of a first line defect on a first sample silicon wafer and a second line defect on a second sample silicon wafer provided in an embodiment of the present disclosure;

[0026] Figure 6 A schematic diagram of a second length of a second linear defect on a second sample silicon wafer provided in an embodiment of the present disclosure;

[0027] Figure 7The first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer provided for the embodiment of the present disclosure are both complete schematic diagrams;

[0028] Figure 8 A schematic diagram showing that a first line defect on a first sample silicon wafer provided in an embodiment of the present disclosure is complete, and a second line defect on a second sample silicon wafer is incomplete;

[0029] Fig. 9 The first line defect on the first sample silicon wafer provided for the embodiment of the present disclosure is not a complete schematic diagram;

[0030] Fig.10 A schematic diagram of a first line defect on a first sample silicon wafer and a second line defect on a second sample silicon wafer corresponding to implementation 1 provided in an embodiment of the present disclosure;

[0031] Fig.11 A schematic diagram of a first line defect on a first sample silicon wafer and a second line defect on a second sample silicon wafer corresponding to implementation 2 provided in an embodiment of the present disclosure;

[0032] Fig.12 A schematic diagram of the composition of a twin defect detection system provided by an embodiment of the present disclosure;

[0033] Fig.13 A schematic diagram of the composition of another twin defect detection system provided by an embodiment of the present disclosure;

[0034] Fig.14 A schematic diagram of the hardware composition of a twin defect detection system provided in an embodiment of the present disclosure;

[0035] Fig.15 A block diagram of a computing device provided for an embodiment of the present disclosure. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure.

[0037] See also Figure 1 , which shows a schematic diagram of the arrangement of silicon atoms in a single crystal silicon rod with twin defects. Figure 1 The twin defect in the single crystal silicon rod shown is caused by an impurity causing the lattice to twist (such as Figure 1 The 4th, 5th and 6th columns in the figure). As the lattice twists, the stress introduced by the impurities is released, causing the twin line to only last for a few or dozens of atomic bond lengths on the plane and then twist back to its original position to grow along the growth axis specified by the seed crystal. At this time, the twin line starts from the starting point and extends for dozens of atomic bond lengths. The thickness of the single crystal silicon rod extends in the single crystal silicon rod, generally in <100> The twin line extends along the (111) crystal plane in the single crystal silicon rod to the edge of the single crystal silicon rod until it leaves the single crystal silicon rod. In other words, this twin line will produce a tens of nanometers thick twin line in the single crystal silicon rod. The twinning defect of the (111) crystal plane will not cause the outer edge of the single crystal silicon rod to break. In other words, Figure 1 Several The twisted arrangement will expand and extend along the (111) crystal plane until it is discharged from the single crystal silicon rod.

[0038] like Figure 2 As shown, it shows a single crystal silicon rod ( Figure 2 The twin defect of the (111) crystal plane in the Figure 2 Although the twin defect is a surface defect of the (111) crystal plane inside the single crystal silicon rod, when the silicon wafer is obtained by wire cutting, it is only a line with a width of several tens of meters in the silicon wafer. Twin line. Since there was no effective means to detect the entire single crystal silicon rod in the early stage, the silicon wafers obtained by online cutting were subjected to grinding, corrosion and polishing processes. The corrosion process was also more likely to cause the silicon wafers to break along the dissociation direction. Therefore, it was difficult to detect the twin defects inside the single crystal silicon rod in the early stage. The above twin defects could not be detected until the final polishing process, resulting in a waste of production capacity.

[0039] The above twin line will extend along the (111) crystal plane inside the single crystal silicon rod to form a twin plane, but the thickness of the twin defect is very thin and will not cause the single crystal silicon rod to lose its single crystality. Therefore, such twin defects may exist in a crystal rod that looks like a complete single crystal, which is difficult to monitor by conventional means. Even when testing by testing means, the above twin defect only appears as a twin line in the silicon wafer, and in the polishing process, for example, a fine line defect may be caused by scratches caused by abrasive particles, or an abnormality of the robot arm during the transfer of the silicon wafer may also scratch a line defect on the surface of the silicon wafer. Therefore, in the actual process, it will also cause the process personnel to speculate that the generation of the twin line on the silicon wafer is caused by scratches caused by abrasive particles or a robot arm, and it is difficult to directly obtain the twin line on the silicon wafer due to the existence of twin defects inside the single crystal silicon rod.

[0040] Based on the above explanation, see Figure 3 , which shows a twin defect detection method provided by an embodiment of the present disclosure, and the detection method specifically includes the following steps.

[0041] In step S301, a first sample silicon wafer and a second sample silicon wafer are obtained by sampling from a single crystal silicon rod to be tested.

[0042] During the specific implementation process, after the first sample silicon wafer and the second sample silicon wafer are obtained by online cutting from the single crystal silicon rod to be tested, they will be chemically polished or finely polished to remove the damaged layer on the surface of the first sample silicon wafer and the second sample silicon wafer, so as to avoid the damaged layer affecting the twin line measurement on the first sample silicon wafer and the second sample silicon wafer.

[0043] Generally speaking, after chemical polishing or fine polishing of the first sample silicon wafer and the second sample silicon wafer, selective etching is performed, and line defects on the first sample silicon wafer and the second sample silicon wafer are tested by selective stress testing or differential interference contrast microscopy.

[0044] It should be noted that in the embodiments of the present disclosure, the etching solution in the above-mentioned preferential etching is not specifically limited.

[0045] In step S302, when the crystal directions of the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer are both parallel to <110> When the crystal direction is the same, a first length corresponding to the first line defect and a second length corresponding to the second line defect are measured respectively; wherein the first length is smaller than the second length.

[0046] like Figure 2 As shown, when there is a twin defect of the (111) crystal plane inside the single crystal silicon rod to be tested, a line defect with a certain width, namely the twin line mentioned above, will appear in the first sample silicon wafer and the second sample silicon wafer obtained by wire cutting.

[0047] Since the twin defect is a plane defect on the (111) crystal plane, the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer are parallel to <110> Therefore, in the embodiment of the present disclosure, when determining whether there is a twin defect inside the single crystal silicon rod to be tested, it is first necessary to determine whether the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer are parallel to <110> Crystal direction.

[0048] It should be noted that if Figure 4 As shown, (111) crystal plane ( Figure 4 The triangle area filled with oblique lines in the figure) and the (100) crystal plane ( Figure 4 The intersection of the quadrilateral area filled with diamonds in the above <110> Crystal direction, where <110> The crystal direction is also the cleavage direction of the silicon wafer mentioned above. In some examples, the embodiments of the present disclosure are described in <110> The crystal direction is also the Notch direction.

[0049] On the other hand, since the twin defect in the single crystal silicon rod to be tested is a surface defect of the (111) crystal plane, and the (111) crystal plane is an equilateral triangle, when the twin defect in the single crystal silicon rod to be tested is as follows Figure 2As shown, in the embodiment of the present disclosure, defining the first length of the first line defect on the first sample silicon wafer to be smaller than the second length of the second line defect on the second sample silicon wafer can indicate that the first sample silicon wafer is located above the second sample silicon wafer, as shown in FIG. Figure 5 As shown, line segment a1 represents a first line defect on the first sample silicon wafer W1, and line segment a2 represents a second line defect on the first sample silicon wafer W2.

[0050] In step S303, based on the first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length and the second length, it is determined whether there is a twin defect inside the single crystal silicon rod to be tested.

[0051] In order to determine whether the first line defect a1 on the first sample silicon wafer W1 and the second line defect a2 on the second sample silicon wafer W2 are caused by, for example, scratches caused by abrasive particles in the polishing process or scratches caused by the robot arm in the transfer process, or whether twin defects are generated in the preparation process of the single crystal silicon rod, thereby causing line defects on the first sample silicon wafer W1 and the second sample silicon wafer W2, based on the characteristics of the twin defects in the embodiment of the present disclosure, according to the first distance (such as the first distance between the first sample silicon wafer W1 and the second sample silicon wafer W2 in the axial direction of the single crystal silicon rod to be tested) between the first sample silicon wafer W1 and the second sample silicon wafer W2 Figure 5 h in FIG), the first length L1 of the first line defect a1 and the second length L2 of the second line defect a2 are used to determine whether there is a twin defect inside the single crystal silicon rod to be tested.

[0052] for Figure 3 The technical solution shown in the figure is to obtain a first sample silicon wafer W1 and a second sample silicon wafer W2 by sampling from a single crystal silicon rod to be tested. When the crystal directions of the first line defect a1 on the first sample silicon wafer W1 and the second line defect a2 on the second sample silicon wafer W2 are both parallel to <110> When measuring the crystal direction, the first length L1 corresponding to the first line defect a1 and the second length L2 corresponding to the second line defect a2 are measured respectively, and then according to the first distance h between the first sample silicon wafer W1 and the second sample silicon wafer W2 in the axial direction of the single crystal silicon rod to be tested, the first length L1 and the second length L2, it can be determined whether there is a twin defect inside the single crystal silicon rod to be tested. Through the technical solution provided by the embodiment of the present disclosure, it is possible to accurately determine whether there is a twin defect inside the single crystal silicon rod, which is different from the naked eye judgment of the process personnel, reduces the judgment error, and not only improves the production efficiency but also reduces the waste of production capacity.

[0053] for Figure 3In some possible implementations of the technical solution shown, based on the first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length and the second length, determining whether there is a twin defect inside the single crystal silicon rod to be tested, and determining whether there is a twin defect inside the single crystal silicon rod to be tested include:

[0054] Acquire a first corresponding relationship between the first distance and a second distance between the first line defect and the second line defect on the (111) crystal plane;

[0055] Draw a perpendicular line from the first end point on the first line defect to the second line defect to obtain an intersection point between the perpendicular line and the second line defect;

[0056] Based on the first length and the second length, obtaining a third distance between a second endpoint on the second line defect close to the intersection and the intersection;

[0057] Obtaining a second corresponding relationship between the second distance and the third distance;

[0058] Based on the first corresponding relationship and the second corresponding relationship, obtaining a third corresponding relationship between the first distance and the third distance;

[0059] When the third corresponding relationship is equal to the preset value, it is determined that a twin defect exists inside the single crystal silicon rod to be tested.

[0060] like Figure 5 As shown, in a specific implementation process, it is assumed that the first sample silicon wafer W1 is located above the second sample silicon wafer W2, and the first length of the first line defect on the first sample silicon wafer is a1, and the first length of the first line defect on the second sample silicon wafer is a2. In some examples, the (111) crystal plane is an equilateral triangle, so Figure 5 The angle α in the figure is 60°. θ is the angle between the (111) crystal plane and the (100) crystal plane, which is 54.7°. In order to determine whether there is a twin defect inside the single crystal silicon rod to be tested, a perpendicular line is drawn from the first end point of the first line defect to the second line defect in the embodiment disclosed in the present invention to obtain the intersection of the perpendicular line and the second line defect a2. The length x between the second end point of the second line defect close to the intersection and the intersection is the third distance mentioned above.

[0061] Depend on Figure 5 It can be seen that the second distance l and the first distance h of the first line defect and the second line defect on the (111) crystal plane are the hypotenuse and a right angle side of the same right triangle. The second distance l and the third distance x are two right angle sides of the same right triangle. Therefore, based on Figure 5The geometric relationship shown can obtain the corresponding relationship between the first distance h and the third distance x.

[0062] For the above implementation, in some examples, the step of obtaining a first corresponding relationship between the first distance and a second distance between the first line defect and the second line defect on the (111) crystal plane includes:

[0063] The first corresponding relationship between the first distance and the second distance between the first line defect and the second line defect on the (111) crystal plane is shown in the following formula:

[0064] sinθ=h / l

[0065] Wherein, h represents the first distance; l represents the second distance; and θ represents the angle between the (111) crystal plane and the (100) crystal plane.

[0066] based on Figure 5 The geometric relationship shown can obtain the first corresponding relationship between the second distance l and the first distance h of the first line defect and the second line defect on the (111) crystal plane: sinθ=h / l.

[0067] For the above implementation, in some examples, the step of obtaining a third distance between a second endpoint on the second line defect close to the intersection and the intersection based on the first length and the second length includes:

[0068] The third distance between the second endpoint on the second line defect close to the intersection and the intersection is obtained according to the following formula:

[0069]

[0070] Among them, L1 represents the above-mentioned first length; L2 represents the above-mentioned second length; and x represents the above-mentioned third distance.

[0071] It should be noted that, when, for example, one end of the second line defect disappears at the edge, the above L2 represents the measured length of the second line defect on the second sample silicon wafer, specifically, Figure 6 shown.

[0072] For the above implementation, in some examples, the step of obtaining a second corresponding relationship between the second distance and the third distance includes:

[0073] The second corresponding relationship between the second distance and the third distance is shown in the following formula:

[0074] tanα=l / x

[0075] Wherein, l represents the second distance; x represents the third distance; α represents the inner angle of the equilateral triangle corresponding to the (111) crystal plane where the first line defect and the second line defect are located.

[0076] based on Figure 5 The geometric relationship shown can obtain the second corresponding relationship between the second distance and the third distance: tanα=l / x.

[0077] For the above implementation, in some examples, the acquiring, based on the above first corresponding relationship and the above second corresponding relationship, a third corresponding relationship between the above first distance and the above third distance includes:

[0078] Based on the first corresponding relationship and the second corresponding relationship, the third corresponding relationship between the first distance and the third distance is calculated and shown as follows:

[0079] h=x×tanα×sinθ

[0080] Among them, h represents the above-mentioned first distance; l represents the above-mentioned second distance; θ represents the angle between the (111) crystal plane and the (100) crystal plane; x represents the above-mentioned third distance; α represents the inner angle of the equilateral triangle corresponding to the (111) crystal plane where the above-mentioned first line defect and the above-mentioned second line defect are located.

[0081] Based on the above description, the third corresponding relationship between the first distance and the third distance is calculated as: h = x × tanα × sinθ. In some examples, α = 60°, θ = 54.7°, so the third corresponding relationship between the first distance and the third distance can be calculated as:

[0082] Therefore, when the first distance h between the two first sample silicon wafers and the second sample silicon wafer on the single crystal silicon rod to be tested and the third distance x satisfy the third corresponding relationship, it can be determined that twin defects exist inside the single crystal silicon rod to be tested.

[0083] for Figure 3 In some possible implementations of the technical solution shown, the above detection method further includes:

[0084] Based on an equilateral triangle corresponding to the (111) crystal plane where the first line defect and the second line defect are located, obtaining a fourth distance from a vertex of the equilateral triangle to the first line defect;

[0085] Based on the fourth distance and the angle between the (111) crystal plane and the (100) crystal plane, a fifth distance from the vertex to the first sample silicon wafer is obtained;

[0086] The fifth distance is used to characterize the position corresponding to the starting point of the twin defect inside the single crystal silicon rod.

[0087] Specifically, based on Figure 5 The geometric relationship shown in can calculate the fourth distance l0 between the starting point O of the twin defect inside the single crystal silicon rod to be tested and the first line defect according to the first length a1 of the first line defect: Based on the calculated fourth distance l0 and the angle θ between the (111) crystal plane and the (100) crystal plane, according to Figure 5 The geometric relationship shown can be used to calculate the fifth distance h0 from the starting point O of the twin defect inside the single crystal silicon rod to be tested to the first sample silicon wafer W1 as: h0 = l0 × sinθ. According to α = 60°, θ = 54.7°, the fifth distance can be calculated as

[0088] In some examples, such as Figure 7 As shown, when the first line defect a1 on the first sample silicon wafer W1 and the second line defect a2 on the second sample silicon wafer W2 are both complete, or as shown in FIG. Figure 8 The first line defect a1 on the first sample silicon wafer W1 is complete, but the second line defect a2 on the second sample silicon wafer W2 is not complete. The above two situations can be explained by The fifth distance from the starting point O of the twin defect inside the single crystal silicon rod to be tested to the first sample silicon wafer W1 is calculated.

[0089] However, if Fig. 9 As shown, if the first line defect a1 on the first sample silicon wafer W1 to be tested is incomplete, that is, the starting point of the twin defect inside the single crystal silicon rod to be tested is relatively close to the edge of the single crystal silicon rod to be tested, then as the (111) crystal plane extends, one end of the first line defect a1 on the first sample silicon wafer W1 to be tested may disappear at the edge of the single crystal silicon rod to be tested. At this time, the aforementioned technical solution can still be used. To determine whether there is a twin defect inside the single crystal silicon rod to be tested, but it is impossible to calculate the specific starting position of the twin defect inside the single crystal silicon rod to be tested. Therefore, it is necessary to take a sample again at the position above the first sample silicon wafer W1 to be tested until a complete first line defect is obtained. Only then can the specific starting position of the twin defect inside the single crystal silicon rod to be tested be calculated.

[0090] The technical solution of the present disclosure is described in detail below through specific embodiments.

[0091] Example 1

[0092] A band saw or a wire saw is used to sample the single crystal silicon rod to obtain a first sample silicon wafer W1 and a first sample silicon wafer W2, wherein the distance between the first sample silicon wafer W1 and the head of the single crystal silicon rod to be tested is 113.25 cm, and the distance between the second sample silicon wafer W2 and the head of the single crystal silicon rod to be tested is 119.98 cm.

[0093] The first sample silicon wafer W1 and the first sample silicon wafer W2 are thinned to remove the damaged layer caused by wire cutting to avoid affecting the stress test. In some examples, the above-mentioned thinning method can be selected as precision grinding and polishing or chemical polishing.

[0094] The line defects on the thinned first sample silicon wafer W1 and the first sample silicon wafer W2 are measured by selectively testing with a corrosion microscope, a stress test, or a differential interference contrast microscope to determine whether the line defects on the first sample silicon wafer W1 and the first sample silicon wafer W2 are a line and whether they are parallel to <110> Crystal direction.

[0095] In this embodiment 1, the presence of line defects on the first sample silicon wafer W1 and the first sample silicon wafer W2 was observed by DIC. Fig.10 As shown: the first line defect a1 on the first sample silicon wafer W1 and the second line defect a2 on the first sample silicon wafer W2 are both complete, and the first line defect a1 on the first sample silicon wafer W1 and the second line defect a2 on the first sample silicon wafer W2 are both parallel to <110> Crystal direction.

[0096] In this embodiment 1, it is known from measurement that the first length L1 of the first line defect a1 is 61.22 mm, and the first length L2 of the second line defect a2 is 157.3 mm, so the calculation yields When twin defects exist in the single crystal silicon rod to be tested, According to the distance between the first sample silicon wafer W1 and the head of the single crystal silicon rod to be tested being 113.25 cm, and the distance between the second sample silicon wafer W2 and the head of the single crystal silicon rod to be tested being 119.98 cm, the first distance between the first sample silicon wafer W1 and the second sample silicon wafer W2 is calculated to be h=119.98-113.25=6.73 cm=67.3 mm. In the specific implementation process, considering that the distance between the first sample silicon wafer W1 and the head of the single crystal silicon rod to be tested and the distance between the second sample silicon wafer W2 and the head of the single crystal silicon rod to be tested are both manually measured, it can be obtained that there are twin defects inside the single crystal silicon rod to be tested if the error is allowed.

[0097] In addition, in Example 1, according to the distance between the first sample silicon wafer W1 and the head of the single crystal silicon rod to be tested being 113.25 cm, and the first length L1 of the first line defect a1 being 61.22 mm, the theoretical calculation yields It can be concluded that the starting point of the twin defect inside the single crystal silicon rod to be tested is located 4.33 cm above the first sample silicon wafer W1, that is, the starting point of the twin defect inside the single crystal silicon rod to be tested is 108.92 cm away from the head of the single crystal silicon rod to be tested.

[0098] It should be noted that, in some examples, sampling was performed again at a distance of 108.92 cm from the head of the single crystal silicon rod to be tested to obtain multiple sample silicon wafers. After grinding and polishing, quality analysis using a high-resolution electron microscope was able to determine that the twin defect was caused by graphite impurities.

[0099] Example 2

[0100] A band saw or a wire saw is used to sample the single crystal silicon rod to obtain a first sample silicon wafer W1 and a first sample silicon wafer W2, wherein the distance between the first sample silicon wafer W1 and the head of the single crystal silicon rod to be tested is 156.92 cm, and the distance between the second sample silicon wafer W2 and the head of the single crystal silicon rod to be tested is 170.15 cm.

[0101] The first sample silicon wafer W1 and the first sample silicon wafer W2 are thinned to remove the damaged layer caused by wire cutting to avoid affecting the stress test. In some examples, the above-mentioned thinning method can be selected as precision grinding and polishing or chemical polishing.

[0102] The line defects on the thinned first sample silicon wafer W1 and the first sample silicon wafer W2 are measured by selectively testing with a corrosion microscope, a stress test, or a differential interference contrast microscope to determine whether the line defects on the first sample silicon wafer W1 and the first sample silicon wafer W2 are a line and whether they are parallel to <110> Crystal direction.

[0103] In this embodiment 2, the presence of line defects on the first sample silicon wafer W1 and the first sample silicon wafer W2 was observed by DIC. Fig.11 As shown in FIG. 1 , the first line defect a1 on the first sample silicon wafer W1 is complete, the second line defect a2 on the first sample silicon wafer W2 has extended out of the surface of the first sample silicon wafer W2, and the first line defect a1 on the first sample silicon wafer W1 and the second line defect a2 on the first sample silicon wafer W2 are both parallel to <110> Crystal direction.

[0104] In this embodiment 2, a perpendicular line is drawn from the right end point of the first line defect a1 to the second line defect a2, and the length of the intersection point and the right end point of the second line defect a2 can be measured as x=93.47 mm. When a twin defect exists in the single crystal silicon rod to be tested, According to the distance between the first sample silicon wafer W1 and the head of the single crystal silicon rod to be tested being 156.92 cm, and the distance between the second sample silicon wafer W2 and the head of the single crystal silicon rod to be tested being 170.15 cm, the first distance between the first sample silicon wafer W1 and the second sample silicon wafer W2 is calculated to be h=170.15-156.92=13.23 cm=132.3 mm. In the specific implementation process, considering that the distance between the first sample silicon wafer W1 and the head of the single crystal silicon rod to be tested and the distance between the second sample silicon wafer W2 and the head of the single crystal silicon rod to be tested are both manually measured, it can be obtained that there are twin defects inside the single crystal silicon rod to be tested if the error is allowed.

[0105] In addition, in Example 2, it is known through measurement that the first length L1 of the first line defect a1 on the first sample silicon wafer W1 is 34.19 mm, and the theoretical calculation yields It can be concluded that the starting point of the twin defect inside the single crystal silicon rod to be tested is located 2.42 cm above the first sample silicon wafer W1, that is, the starting point of the twin defect inside the single crystal silicon rod to be tested is 154.5 cm away from the head of the single crystal silicon rod to be tested.

[0106] It should be noted that, in some examples, sampling is performed again at a distance of 154.5 cm from the head of the single crystal silicon rod to be tested to obtain multiple sample silicon wafers. After grinding and polishing, quality analysis using a high-resolution electron microscope can determine the cause of the twin defect.

[0107] Based on the same inventive concept as the above technical solution, see Fig.12 , which shows that the above detection system 120 provided by the embodiment of the present disclosure includes: a sampling unit 1201, a measuring unit 1202 and a determining unit 1203; wherein,

[0108] The sampling unit 1201 is used to sample the single crystal silicon rod to be tested to obtain a first sample silicon wafer and a second sample silicon wafer;

[0109] The measuring unit 1202 is configured to measure the first twin line on the first sample silicon wafer and the second twin line on the second sample silicon wafer when the crystal directions are parallel to <110> When the crystal direction is the same, a first length corresponding to the first twin line and a second length corresponding to the second twin line are measured respectively; wherein the first length is smaller than the second length;

[0110] The determination unit 1203 is configured to determine whether there is a twin defect inside the single crystal silicon rod to be tested based on the first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length and the second length.

[0111] Optionally, in some examples, the determination unit 1203 is configured to:

[0112] Acquire a first corresponding relationship between the first distance and a second distance between the first line defect and the second line defect on the (111) crystal plane;

[0113] Draw a perpendicular line from the first end point on the first line defect to the second line defect to obtain an intersection point between the perpendicular line and the second line defect;

[0114] Based on the first length and the second length, obtaining a third distance between a second endpoint on the second line defect close to the intersection and the intersection;

[0115] Obtaining a second corresponding relationship between the second distance and the third distance;

[0116] Based on the first corresponding relationship and the second corresponding relationship, obtaining a third corresponding relationship between the first distance and the third distance;

[0117] When the third corresponding relationship is equal to the preset value, it is determined that a twin defect exists inside the single crystal silicon rod to be tested.

[0118] Optionally, in some examples, the determination unit 1203 is configured to:

[0119] The first corresponding relationship between the first distance and the second distance between the first line defect and the second line defect on the (111) crystal plane is shown in the following formula:

[0120] sinθ=h / l

[0121] Wherein, h represents the first distance; l represents the second distance; and θ represents the angle between the (111) crystal plane and the (100) crystal plane.

[0122] Optionally, in some examples, the determination unit 1203 is configured to:

[0123] The third distance between the second endpoint on the second line defect close to the intersection and the intersection is obtained according to the following formula:

[0124]

[0125] Among them, L1 represents the above-mentioned first length; L2 represents the above-mentioned second length; and x represents the above-mentioned third distance.

[0126] Optionally, in some examples, the determination unit 1203 is configured to:

[0127] The second corresponding relationship between the second distance and the third distance is shown in the following formula:

[0128] tanα=l / x

[0129] Wherein, l represents the second distance; x represents the third distance; α represents the inner angle of the equilateral triangle corresponding to the (111) crystal plane where the first line defect and the second line defect are located.

[0130] Optionally, in some examples, the determination unit 1203 is configured to:

[0131] Based on the first corresponding relationship and the second corresponding relationship, the third corresponding relationship between the first distance and the third distance is calculated and shown as follows:

[0132] h=x×tanα×sinθ

[0133] Among them, h represents the above-mentioned first distance; l represents the above-mentioned second distance; θ represents the angle between the (111) crystal plane and the (100) crystal plane; x represents the above-mentioned third distance; α represents the inner angle of the equilateral triangle corresponding to the (111) crystal plane where the above-mentioned first line defect and the above-mentioned second line defect are located.

[0134] Optionally, in some examples, such as Fig.13 As shown, the detection system 120 further includes a determination unit 1204, and the determination unit 1204 is configured to:

[0135] Based on an equilateral triangle corresponding to the (111) crystal plane where the first line defect and the second line defect are located, obtaining a fourth distance from a vertex of the equilateral triangle to the first line defect;

[0136] Based on the fourth distance and the angle between the (111) crystal plane and the (100) crystal plane, a fifth distance from the vertex to the first sample silicon wafer is obtained;

[0137] The fifth distance is used to characterize the position corresponding to the starting point of the twin defect inside the single crystal silicon rod.

[0138] It can be understood that in this embodiment, the "part" can be a part of the circuit, a part of the processor, a part of the program or software, etc., and of course it can also be a unit, a module, or a non-modular one.

[0139] In addition, each component in this embodiment may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of software function modules.

[0140] If the above integrated unit is implemented in the form of a software function module and is not sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this embodiment is essentially or the part that contributes to the prior art or the whole or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) or a processor to perform all or part of the steps of the above method of this embodiment. The aforementioned storage medium includes: U disk, mobile hard disk, read only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program codes.

[0141] Therefore, an embodiment of the present disclosure provides a computer storage medium, wherein the computer storage medium stores a twin defect detection program, and the twin defect detection program is executed by at least one processor to perform the steps of the twin defect detection method described in the aforementioned technical solution.

[0142] Based on the above twin defect detection system 120 and computer storage medium, see Fig.14 , which shows the hardware structure of the twin defect detection system 120, which may include: a band saw 141 or a wire cutting machine 142, and a data processing subsystem 143; wherein,

[0143] The band saw 141 or the wire saw 142 is used to sample the single crystal silicon rod to be tested to obtain a first sample silicon wafer and a second sample silicon wafer;

[0144] The data processing subsystem 143 is configured as follows:

[0145] When the crystal directions of the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer are parallel to <110> When the crystal direction is the same, a first length corresponding to the first line defect and a second length corresponding to the second line defect are measured respectively; wherein the first length is smaller than the second length;

[0146] Based on the first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length and the second length, it is determined whether there is a twin defect inside the single crystal silicon rod to be tested.

[0147] Specifically, the data processing subsystem 143 can be Fig.15 The computing device shown is implemented as Fig.15As shown, the computing device in the present disclosure may include one or more of the following components: a processor 1510 and a memory 1520 .

[0148] Optionally, the processor 1510 uses various interfaces and lines to connect various parts of the entire computing device, and executes various functions of the computing device and processes data by running or executing instructions, programs, code sets or instruction sets stored in the memory 1520, and calling data stored in the memory 1520. Optionally, the processor 1510 can be implemented in at least one hardware form of digital signal processing (DSP), field-programmable gate array (FPGA), and programmable logic array (PLA). The processor 1510 can integrate one or a combination of a central processing unit (CPU), a graphics processing unit (GPU), a neural network processor (NPU), and a baseband chip. Among them, the CPU mainly processes the operating system, user interface, and application programs; the GPU is responsible for rendering and drawing the content that needs to be displayed on the touch display; the NPU is used to implement artificial intelligence (AI) functions; and the baseband chip is used to process wireless communications. It is understandable that the above-mentioned baseband chip may not be integrated into the processor 1510, but may be implemented by a separate chip.

[0149] The memory 1520 may include a random access memory (RAM) or a read-only memory (ROM). Optionally, the memory 1520 includes a non-transitory computer-readable storage medium. The memory 920 may be used to store instructions, programs, codes, code sets, or instruction sets. The memory 1520 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above various method embodiments, etc.; the data storage area may store data created according to the use of the computing device, etc.

[0150] In addition, those skilled in the art will appreciate that the structure of the computing device shown in the above figures does not constitute a limitation on the computing device, and the computing device may include more or fewer components than shown, or combine certain components, or arrange the components differently. For example, the computing device also includes a display screen, a camera assembly, a microphone, a speaker, a radio frequency circuit, an input unit, a sensor (such as an acceleration sensor, an angular velocity sensor, a light sensor, etc.), an audio circuit, a WiFi module, a power supply, a Bluetooth module, and other components, which will not be described in detail here.

[0151] It should be noted that the technical solutions described in the embodiments of the present disclosure can be combined arbitrarily without conflict.

[0152] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A method for detecting twin defects, characterized in that: The detection method comprises: Sampling the single crystal silicon rod to be tested to obtain a first sample silicon wafer and a second sample silicon wafer; When the crystal directions of the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer are both parallel to <110> When the first line defect has a first length corresponding to the first line defect and the second line defect has a second length corresponding to the second line defect, the first length is smaller than the second length. Determining whether there is a twin defect inside the single crystal silicon rod to be tested based on a first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length, and the second length; Wherein, determining whether there is a twin defect inside the single crystal silicon rod to be tested based on a first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length, and the second length, comprises: Acquire a first corresponding relationship between the first distance and a second distance between the first line defect and the second line defect on a (111) crystal plane; Draw a perpendicular line from a first end point on the first line defect to the second line defect to obtain an intersection point between the perpendicular line and the second line defect; Based on the first length and the second length, obtaining a third distance between a second endpoint on the second line defect close to the intersection and the intersection; Acquire a second corresponding relationship between the second distance and the third distance; Based on the first corresponding relationship and the second corresponding relationship, acquiring a third corresponding relationship between the first distance and the third distance; When the third corresponding relationship is equal to the preset value, it is determined that a twin defect exists inside the single crystal silicon rod to be tested.

2. The detection method according to claim 1, characterized in that: The obtaining of a first corresponding relationship between the first distance and a second distance between the first line defect and the second line defect on the (111) crystal plane includes: A first corresponding relationship between the first distance and a second distance between the first line defect and the second line defect on the (111) crystal plane is shown in the following formula: in, h represents the first distance; l represents the second distance; Represents the angle between the (111) crystal plane and the (100) crystal plane.

3. The detection method according to claim 1, characterized in that: The acquiring, based on the first length and the second length, a third distance between a second endpoint on the second line defect close to the intersection and the intersection, comprises: The third distance between the second endpoint close to the intersection point on the second line defect and the intersection point is obtained according to the following formula: in, L 1 represents the first length; L 2 represents the second length; x represents the third distance.

4. The detection method according to claim 1, characterized in that: The acquiring a second corresponding relationship between the second distance and the third distance includes: The second corresponding relationship between the second distance and the third distance is shown in the following formula: tanα = l / x in, l represents the second distance; x represents the third distance; α represents the inner angle of the equilateral triangle corresponding to the (111) crystal plane where the first line defect and the second line defect are located.

5. The detection method according to claim 1, characterized in that: The acquiring, based on the first corresponding relationship and the second corresponding relationship, a third corresponding relationship between the first distance and the third distance includes: Based on the first corresponding relationship and the second corresponding relationship, the third corresponding relationship between the first distance and the third distance is calculated and shown in the following formula: in, h represents the first distance; l represents the second distance; represents the angle between the (111) crystal plane and the (100) crystal plane; x represents the third distance; α represents the inner angle of the equilateral triangle corresponding to the (111) crystal plane where the first line defect and the second line defect are located.

6. The detection method according to claim 1, characterized in that: The detection method further comprises: Based on an equilateral triangle corresponding to the (111) crystal plane where the first line defect and the second line defect are located, obtaining a fourth distance from a vertex of the equilateral triangle to the first line defect; Based on the fourth distance and the angle between the (111) crystal plane and the (100) crystal plane, obtaining a fifth distance from the vertex to the first sample silicon wafer; The fifth distance is used to characterize the position corresponding to the starting point of the twin defect inside the single crystal silicon rod.

7. A twin defect detection system, characterized in that: The detection system comprises: a sampling unit, a measuring unit and a determining unit; wherein, The sampling part is used to sample the single crystal silicon rod to be tested to obtain a first sample silicon wafer and a second sample silicon wafer; The measuring unit is configured to measure the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer when the crystal directions of the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer are both parallel to <110> When the first line defect has a first length corresponding to the first line defect and the second line defect has a second length corresponding to the second line defect, the first length is smaller than the second length. The determination unit is configured to determine whether there is a twin defect inside the single crystal silicon rod to be tested based on a first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length, and the second length; Wherein, the measuring unit is configured as follows: Acquire a first corresponding relationship between the first distance and a second distance between the first line defect and the second line defect on a (111) crystal plane; Draw a perpendicular line from a first end point on the first line defect to the second line defect to obtain an intersection point between the perpendicular line and the second line defect; Based on the first length and the second length, obtaining a third distance between a second endpoint on the second line defect close to the intersection and the intersection; Acquire a second corresponding relationship between the second distance and the third distance; Based on the first corresponding relationship and the second corresponding relationship, acquiring a third corresponding relationship between the first distance and the third distance; When the third corresponding relationship is equal to the preset value, it is determined that a twin defect exists inside the single crystal silicon rod to be tested.

8. A twin defect detection system, characterized in that: The detection system includes a band saw or a wire cutting machine, and a data processing subsystem; wherein, The band saw or the wire saw is used to sample the single crystal silicon rod to be tested to obtain a first sample silicon wafer and a second sample silicon wafer; The data processing subsystem is configured as follows: When the crystal directions of the first line defect on the first sample silicon wafer and the second line defect on the second sample silicon wafer are both parallel to <110> When the first line defect has a first length corresponding to the first line defect and the second line defect has a second length corresponding to the second line defect, the first length is smaller than the second length. Based on a first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length, and the second length, determining whether there is a twin defect inside the single crystal silicon rod to be tested; wherein, based on the first distance between the first sample silicon wafer and the second sample silicon wafer in the axial direction of the single crystal silicon rod to be tested, the first length, and the second length, determining whether there is a twin defect inside the single crystal silicon rod to be tested comprises: Acquire a first corresponding relationship between the first distance and a second distance between the first line defect and the second line defect on a (111) crystal plane; Draw a perpendicular line from a first end point on the first line defect to the second line defect to obtain an intersection point between the perpendicular line and the second line defect; Based on the first length and the second length, obtaining a third distance between a second endpoint on the second line defect close to the intersection and the intersection; Acquire a second corresponding relationship between the second distance and the third distance; Based on the first corresponding relationship and the second corresponding relationship, acquiring a third corresponding relationship between the first distance and the third distance; When the third corresponding relationship is equal to the preset value, it is determined that a twin defect exists inside the single crystal silicon rod to be tested.

9. A computer storage medium, characterized in that: The computer storage medium stores a twin defect detection program, and the twin defect detection program is executed by at least one processor to perform the steps of the twin defect detection method according to any one of claims 1 to 6.

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