Management method for surface defect inspection apparatus and reference wafer

Abstract

To provide a management method of a surface defect inspection device capable of detecting abnormality of only a high angle scattering detector of the surface defect inspection device, and performing calibration to the device detecting the abnormality.SOLUTION: In the management method of the surface defect inspection device mounted with a high / low angle scattering detector, as a standard wafer, a semiconductor Si wafer in which a plurality of defects having a convex or concave shape in which a dimension in a direction parallel to a surface is larger than a dimension in a vertical direction and a known coordinate and size are formed on an outermost surface is prepared. A method for managing a surface defect inspection apparatus, the method comprising: detecting scattered light from a defect of a standard wafer by a detector in an apparatus to be managed; acquiring coordinates and a size of the defect; calculating a detection size difference for each detector, the detection size difference being a difference between a known size of the standard wafer and the detected size for the defect at the same coordinates; and inspecting and calibrating an optical system of the apparatus when an absolute value of a mode of the detection size difference of a high-angle scattering detector is larger than that of a low-angle scattering detector.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for managing a surface defect inspection apparatus and a standard wafer. [Background technology]

[0002] Semiconductor silicon wafers are used in a variety of semiconductor devices, and it is necessary to deliver substrates that meet the requirements of device manufacturers. During the wafer manufacturing process, defective products that do not meet customer requirements may occur. To prevent defective products from being delivered to customers, wafer manufacturers use a variety of inspection equipment to perform shipping inspections. For this reason, inspection equipment must always be in good working order, and any abnormalities that occur must be detected promptly and corrected to a normal state.

[0003] Patent Document 1 discloses a technology for generating a difference value between a signal obtained from an image of a measurement target and a signal obtained from a reference image, as well as a frequency distribution of the difference values, and determining whether the frequency distribution satisfies predetermined conditions.

[0004] Patent Document 2 discloses a technology in which one or more micro-pits of approximately the same size, with a scattered light intensity equivalent to the scattered light intensity of a standard particle with a specified particle size, are generated in a certain micro-region on the oxide film of a silicon wafer, to prepare a calibration reference wafer on which a group of micro-pits is formed, and the calibration reference wafer is irradiated with laser light from a particle counter, and the particle counter is calibrated based on the measurement results of the scattered light. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-173252 [Patent Document 2] Japanese Patent Application Publication No. 11-014534 Summary of the Invention [Problem to be solved by the invention]

[0006] Surface defect inspection is an important inspection required by wafer manufacturers. Surface defect inspection equipment (particle counters) are usually used to inspect surface defects present on the wafer surface. Particle counters are calibrated so that the same defect is detected at the same size regardless of the equipment used to measure it. A standard wafer coated with silica of a known size is used to inspect and calibrate each device. This allows for management to ensure that a specific scattered light intensity is correctly converted to a known size. If necessary, the standard wafer can be used for daily management, and if an abnormality is found during measurements during daily management, the device can be inspected. However, in particle counters equipped with multiple detectors, even if an optical system abnormality occurs that adversely affects only the high-angle scattering detector, the abnormality may not be detected during daily management using a silica-coated standard wafer.

[0007] Patent Document 1 describes a technology for determining whether to adjust the device based on the frequency distribution of the difference values ​​obtained from the acquired image and the reference image, but does not describe a means for observing abnormalities in the optical system that have a negative effect only on the high-angle scattering detector. Furthermore, Patent Document 2 discloses a technology in which pits having a scattered light intensity equivalent to that of scattered light generated by standard particles of known size are formed on the oxide film of a silicon wafer, and a particle counter is calibrated using the measurement results of the wafer. However, it does not disclose a means for detecting an abnormality in the optical system that adversely affects only the high-angle scattering detector.

[0008] The present invention has been made to solve the above problems, and aims to provide a method for managing surface defect inspection devices that can detect optical system abnormalities that have a negative effect only on the high-angle scattering detector of a surface defect inspection device, and can perform calibration on devices in which an abnormality is detected. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a method for managing a surface defect inspection apparatus that inspects surface defects of semiconductor silicon wafers, the apparatus being equipped with a high-angle scattering detector and a low-angle scattering detector having a detection angle lower than that of the high-angle scattering detector, and comprising the steps of: a standard wafer preparation step of preparing, as a standard wafer for managing the surface defect inspection device, a semiconductor silicon wafer having a convex or concave shape whose dimension parallel to the wafer surface is greater than the dimension perpendicular to the wafer surface and on whose outermost surface a plurality of defects whose coordinates and sizes are known are formed; a defect detection step of irradiating a laser onto the surface of the standard wafer using a surface defect inspection device to be managed, detecting scattered light generated by defects present on the outermost surface of the standard wafer with the detector, and acquiring coordinates and sizes of the defects; a size shift calculation step of comparing known coordinates of defects on the standard wafer with coordinates of defects detected in the defect detection step, and calculating, for each detector, a detected size difference that is a difference between the known size on the standard wafer and the size detected in the defect detection step, for defects at the same coordinates; a mode acquiring step of acquiring, for each detector, the absolute value of the mode of the detected size difference from the calculated detected size difference; an inspection and calibration step of inspecting and calibrating an optical system of the surface defect inspection device when the absolute value of the most frequent value of the detected size difference in the high-angle scattering detector is greater than the absolute value of the most frequent value of the detected size difference in the low-angle scattering detector; The present invention provides a method for managing a surface defect inspection device, comprising:

[0010] In the present invention, a standard wafer is used that has a plurality of defects of the above dimensions, in other words, defects with a small defect height or a shallow defect depth, so that the high-angle scattering component in the scattered light during laser irradiation can be increased, thereby making it possible to easily detect anomalies in the high-angle scattering detector. Furthermore, by carrying out the above steps, it is possible to quickly detect abnormalities in the optical system that have a negative effect only on the high-angle scattering detector of the surface defect inspection device (hereinafter simply referred to as abnormalities in the high-angle scattering detector only), and to inspect and calibrate the optical system of the device.

[0011] In addition, when acquiring the absolute value of the most frequent value of the detected size difference in the mode acquisition step, A frequency distribution curve of the detected size difference can be generated and obtained.

[0012] In this way, the absolute value of the most frequent value of the detected size difference can be obtained more easily.

[0013] Further, in the standard wafer preparation step, when preparing the standard wafer, A semiconductor silicon wafer having pits or PIDs formed as the defects can be prepared.

[0014] Such pits and PID defects can be formed relatively easily and conveniently.

[0015] Further, in the standard wafer preparation step, when preparing the standard wafer, A semiconductor silicon wafer can be prepared in which defects having a size of 100 nm or less are formed as the defects.

[0016] The smaller the defect detection size, the smaller the sizing error tends to be. Therefore, it is preferable to prepare a standard wafer with small defects of 100 nm or less. This is because it is effective in suppressing the difference in detection size caused by errors and more accurately calculating the difference in detection size caused by anomalies in the high-angle scattering detector alone.

[0017] The present invention also provides a standard wafer for managing a surface defect inspection apparatus, comprising: The standard wafer is a semiconductor silicon wafer having a plurality of convex or concave defects formed on the outermost surface, the dimension of which in a direction parallel to the wafer surface is greater than the dimension in a direction perpendicular to the wafer surface.

[0018] In the case of such a standard wafer of the present invention, the defects formed thereon are low in height or shallow in depth, as described above, and therefore the high-angle scattering component can be increased in the scattered light during laser irradiation, making it possible to easily detect abnormalities in the high-angle scattering detector.

[0019] The defect may be a pit or a PID.

[0020] Such pits and PID defects can be formed relatively easily and can be easily prepared.

[0021] The defects may be 100 nm or less in size.

[0022] Such a configuration is effective in suppressing the difference in detected size caused by errors and more accurately calculating the difference in detected size caused by an abnormality in only the high-angle scattering detector. [Effects of the Invention]

[0023] The method for managing a surface defect inspection apparatus of the present invention makes it possible to quickly detect an abnormality in the optical system that adversely affects only the high-angle scattering detector, and to inspect and calibrate the optical system of the apparatus. Furthermore, with the standard wafer of the present invention, it is possible to increase the high-angle scattered component in the scattered light during laser irradiation, making it possible to easily detect abnormalities in the high-angle scattered light detector. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram showing an example of a standard wafer of the present invention. [Figure 2]1 is a flowchart showing an example of steps in a method for managing a surface defect inspection device according to the present invention. [Figure 3] FIG. 1 is a schematic diagram showing an example of a conventional standard wafer. [Figure 4] FIG. 10 is an explanatory diagram showing an example of a reference for the coordinates of a defect. DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention will be described in detail below as an example of an embodiment with reference to the drawings, but the present invention is not limited to this. As described above, there has been a demand for a method of managing a surface defect inspection device that can detect an abnormality in the optical system that adversely affects only the high-angle scattering detector of the surface defect inspection device and can perform calibration for the device in which an abnormality has been detected. Therefore, the present inventors have conducted extensive research into a method of managing such a surface defect inspection device.

[0026] The present inventors have also devised a method for managing a surface defect inspection device that is equipped with a high-angle scattering detector and a low-angle scattering detector having a detection angle lower than that of the high-angle scattering detector as detectors and that inspects surface defects of semiconductor silicon wafers, the method comprising the steps of: a standard wafer preparation step (preparing, as a standard wafer for managing the surface defect inspection device, a semiconductor silicon wafer that has a convex or concave shape whose dimension parallel to the wafer surface is greater than the dimension perpendicular to the wafer surface and that has a plurality of defects formed on its outermost surface whose coordinates and sizes are known); a defect detection step (using the surface defect inspection device to be managed, irradiating a laser onto the surface of the standard wafer, detecting scattered light generated by the defects present on the outermost surface of the standard wafer with the detector, and obtaining the coordinates and sizes of the defects); and a size shift calculation step (preparing the standard wafer for managing the standard wafer, The inventors have found that a method for managing a surface defect inspection device comprising the steps of: comparing known coordinates of defects in the high-angle scattering detector with coordinates of defects detected in the defect detection process, and calculating, for each detector, a detected size difference, which is the difference between the known size on the standard wafer and the size detected in the defect detection process, for defects at the same coordinates; a mode acquisition process (obtaining, for each detector, the absolute value of the mode of the detected size difference from the calculated detected size difference); and an inspection and calibration process (inspecting and calibrating the optical system of the surface defect inspection device if the absolute value of the mode of the detected size difference in the high-angle scattering detector is greater than the absolute value of the mode of the detected size difference in the low-angle scattering detector), can quickly detect abnormalities in only the high-angle scattering detector as described above, and can properly inspect and calibrate the optical system of the device, thereby completing the present invention.

[0027] Furthermore, the inventors have found that a standard wafer for controlling a surface defect inspection device, which is a semiconductor silicon wafer having a plurality of convex or concave defects formed on its outermost surface, the dimension parallel to the wafer surface being greater than the dimension perpendicular to the wafer surface, has a large amount of high-angle scattered components in the scattered light when irradiated with a laser, and is therefore suitable for detecting abnormalities with a high-angle scattering detector, thereby completing the present invention.

[0028] An example of a standard wafer of the present invention is shown in Figure 1. This is a standard wafer (semiconductor silicon wafer) for controlling a surface defect inspection device, and as shown in Figure 1, there are multiple defects on its outermost surface. The number of defects may be any number. The more defects there are, the more detection samples there are, which allows for the calculation of a larger number of detection size differences (described later), and is more preferable for obtaining the absolute value of the most frequent value of the detection size differences. From this perspective, the more defects there are, the better, and although there is no set upper limit, taking into account factors such as the time required for detection, a number of 50,000 defects is efficient.

[0029] The defect shape may be either convex or concave relative to the wafer surface. However, when comparing the dimension parallel to the wafer surface with the dimension perpendicular to the wafer surface, the defect shape is larger in the former direction than in the latter direction. In other words, the defect height is low or the defect depth is shallow.

[0030] Here, the significance of the above-mentioned defect shape will be explained. First, an example of a conventional standard wafer, i.e., a standard wafer with defects dominated by spheres, such as a silica-coated semiconductor silicon wafer, is shown in Figure 3. When a laser is irradiated from the detector of a surface defect inspection system on the conventional standard wafer shown in Figure 3, the high-angle scattering component is small, making it difficult for the high-angle scattering detector to detect abnormalities. On the other hand, defects with low defect heights or shallow defect depths on the standard wafer of the present invention shown in Figure 1 have many high-angle scattering components, making it easy to detect anomalies with a high-angle scattering detector. Therefore, this defect shape is extremely useful for detecting anomalies with a high-angle scattering detector.

[0031] Furthermore, the size and type of the defect are not particularly limited. Since the smaller the detection size, the smaller the sizing error tends to be, it is more preferable to have a defect size of 100 nm or less. Note that the size here refers to the diameter of a sphere when the defect is assumed to have a spherical shape. The lower limit of the defect size should be greater than 0 nm, and should be a size that can be detected by a high-angle scattering detector.

[0032] Furthermore, if the defects are pits or PIDs, they can be formed relatively easily, making them a standard wafer that can be easily prepared. For example, a semiconductor silicon wafer with many pits may be produced by growing the crystal under conditions that favor vacancy formation, and then processing the wafer using a conventional method. Alternatively, a semiconductor silicon wafer having many PIDs may be prepared by spin-coating a Ni standard solution onto the wafer, subjecting it to a diffusion heat treatment, and then polishing it. The concentration of the Ni standard solution is not particularly limited, but the lower the concentration, the more likely it is that PIDs with a smaller detectable size will be formed. Preferably, the concentration on the wafer surface is 1×10 11 atoms / cm 2 The temperature and time of the diffusion heat treatment may be set to less than 800°C for 5 hours, provided that the temperature and time are sufficient for Ni to reach the rear surface. The polishing depth is not particularly limited, but may be set to 250 nm, for example. This allows scratches and particles introduced during the intentional contamination process to be efficiently removed.

[0033] As mentioned above, the defects in the standard wafer of the present invention are not limited to pits or PIDs, but may have the above-mentioned shape (i.e., a shape whose dimensions in the directions parallel and perpendicular to the wafer surface satisfy the above-mentioned magnitude relationship). The wafer may have a plurality of defects on its outermost surface that satisfy this relationship, and the manufacturing process is not limited. It may be manufactured by a general method, or may be manufactured by special processing.

[0034] Next, a method for managing a surface defect inspection device according to the present invention will be described. An example of the steps of the management method according to the present invention is shown in FIG. Overall, the process consists of S1: standard wafer preparation process, S2: defect detection process, S3: size shift calculation process, S4: mode value acquisition process, and S5: inspection and calibration process. Each process is described in detail below.

[0035] (S1: Standard wafer preparation process) As a standard wafer for managing a surface defect inspection device, a semiconductor silicon wafer is prepared, which has a convex or concave shape whose dimension parallel to the wafer surface is greater than the dimension perpendicular to the wafer surface, and which has multiple defects with known coordinates and sizes formed on its outermost surface. Specifically, first, a semiconductor silicon wafer is prepared on which defects are formed on the top surface as shown in Figure 1. If the coordinates and sizes of the defects on this semiconductor silicon wafer are already known, the wafer is used as a standard wafer. On the other hand, if these are not yet known, the coordinates and size of the defects are obtained, for example, using a normal surface defect inspection device. That is, a laser is irradiated onto the surface of this semiconductor silicon wafer, and the scattered light generated by the defects is detected with detectors (a high-angle scattering detector and a low-angle scattering detector (a detector with a detection angle lower than that of the high-angle scattering detector)), and the coordinates and size of the defects are obtained. This makes it possible to prepare a standard wafer with known defect coordinates and sizes. The coordinate reference (setting of coordinate axes) of a known defect is not particularly limited, but can be set as shown in Figure 4. In the case of Figure 4, the origin is set at the lower left position of the wafer in plan view. In other words, the origin is set to the point where the tangent to the left edge of the wafer outer periphery and the tangent to the bottom edge intersect perpendicularly in plan view. For example, for a wafer with a diameter of 300 mm, the coordinates (X, Y) of the wafer center are (150 mm, 150 mm). Naturally, this is not a limitation, and the setting of the coordinate axes can be determined as appropriate. The sizes of the known defects are the sizes acquired by the high-angle scattering detector and the low-angle scattering detector, because even when the same defect is detected, there is usually a difference in the size detected by the high-angle scattering detector and the low-angle scattering detector, and also because in a later process, the sizes acquired by both detectors of the surface defect inspection device to be managed will be compared for each detector.

[0036] A normal surface defect inspection device here means a surface defect inspection device that is free of any problems, can correctly convert a given scattered light intensity into a given detection size, and is capable of detecting the same defect as the same size if it is the same model of device. Furthermore, the normal device and the device to be managed (described later) do not necessarily have to be the same device, but can be another device of the same model. Since the same model has the same optical system, adjustments can be made so that any device in a normal state detects all defects at the same size. Of course, the coordinates and size detected using the same device when it was in a normal state may be used as the known coordinates and size.

[0037] (S2: Defect detection process) Using a surface defect inspection device to be managed, a laser is irradiated onto the surface of a standard wafer, and scattered light generated by defects present on the outermost surface of the standard wafer is detected by a detector, thereby obtaining the coordinates and size of the defects. The surface defect inspection device to be managed is equipped with a high-angle scattering detector and a low-angle scattering detector (a detector with a detection angle lower than that of the high-angle scattering detector), and is the device to be inspected to see if there is an abnormality in only the high-angle scattering detector. The coordinates and sizes of the defects are acquired by the low-angle scattering detector and the high-angle scattering detector, respectively.

[0038] (S3: Size shift calculation process) The known coordinates of defects on the standard wafer are compared with the coordinates of defects detected in the defect detection process, and for defects at the same coordinates, the detected size difference, which is the difference between the known size on the standard wafer and the size detected in the defect detection process, is calculated for each detector. That is, the following calculation formula can be used for both detectors. <For low-angle scattering detector: Calculation formula L> [Detection size difference (low-angle scattering detector version)] = [Known size (low-angle scattering detector version)] - [Detection size in defect detection process (low-angle scattering detector version)] <For high-angle scattering detectors: Calculation formula H> [Detection size difference (high-angle scattering detector version)] = [Known size (high-angle scattering detector version)] - [Detection size in defect detection process (high-angle scattering detector version)]

[0039] For example, suppose there is a defect that is normally (detected by a properly functioning surface defect inspection device) (S1 process) detected as 30 nm by the low-angle scattering detector and 40 nm by the high-angle scattering detector. Then, suppose there is an abnormality in the optical system of only the high-angle scattering detector in the surface defect inspection device to be managed in S2 process, causing only the detected size to be smaller, resulting in detection of 30 nm by the low-angle scattering detector and 35 nm by the high-angle scattering detector. In this case, the difference in detected size in S3 process is 0 nm by the low-angle scattering detector and 5 nm by the high-angle scattering detector.

[0040] (S4: Mode acquisition process) From the calculated detection size difference, the absolute value of the most frequent value of the detection size difference is obtained for each detector. In this case, it is preferable to create a frequency distribution curve of the detected size difference, since this can be easily obtained. As in the above example, when an abnormality occurs in the optical system of the detector, the detected size generally tends to be smaller than the known size. Therefore, in the calculation formulas L and H, which subtract from the known size, the detected size difference is usually a positive value. Therefore, the most common value of the detected size difference is also a positive value. On the other hand, unlike formulas L and H, in the case of a formula that subtracts from the detected size in the defect detection process, the detected size difference and its most frequent value will be negative values. However, in the present invention, since it is defined as the absolute value of the most frequent value of the detected size difference, it is possible to use either type of calculation formula.

[0041] In discovering the present invention, the inventors also considered other possible criteria, such as average and maximum values, which are other statistical values. However, when large particles whose size saturates are reduced in size by laser irradiation, the size shift (detected size difference) becomes significantly larger, which has a greater impact on the results than size shift due to detector abnormalities. Therefore, average and maximum values ​​are not suitable as criteria. Because the size shift follows a normal distribution, the mode, which can be used to exclude outliers, is more suitable.

[0042] (S5: Inspection and calibration process) When the absolute value of the most frequent value of the size difference detected by the high-angle scattering detector is greater than the absolute value of the most frequent value of the size difference detected by the low-angle scattering detector, inspection and calibration of the optical system of the surface defect inspection device is performed.

[0043] In rare cases, the detection size may shift due to deterioration of the standard wafer, whether it is a conventional standard wafer coated with silica or the standard wafer of the present invention. In this case, the shift tends to be approximately the same for all detectors. On the other hand, anomalies specific to the large-angle scattering detector are observed as changes in the size detected by the large-angle scattering detector alone. Therefore, to confirm that the observed size shift is specific to the large-angle scattering detector, the present invention uses a system equipped with not only a large-angle scattering detector but also a low-angle scattering detector, and compares the absolute values ​​of the most frequent values ​​of the detected size differences as described above. This allows for the rapid detection of anomalies in the optical system that adversely affect only the large-angle scattering detector, and allows for appropriate inspection and calibration of the optical system of the device. The optical system of the high-angle scattering detector is inspected and calibrated, for example, by adjusting the optical axis. [Example]

[0044] EXAMPLES The present invention will be explained in more detail below by showing examples of the present invention, but the present invention is not limited to these examples. (Example) First, we produced silicon single crystals under conditions that favor vacancy formation as standard semiconductor silicon wafers, and then processed the wafers using conventional methods (slicing, lapping / grinding, etching, and polishing) to produce mirror-finished silicon wafers with a diameter of 300 mm and a large number (26,000) of pits (defects) with detectable sizes of at least 15 to 100 nm. We then confirmed that the dimension parallel to the wafer surface was larger than the dimension perpendicular to the surface, and that these pits were shallow defects. Next, we used the SP7 particle counter (normal surface defect inspection device) manufactured by KLA, which is equipped with a low-angle scattering detector and a high-angle scattering detector and has been confirmed to be in a normal state, capable of detecting all defects at the same size as other models. XP Measurement was performed in oblique mode / 15 nm up using a detector, and scattered light generated by defects present on the top surface of the standard wafer was detected with detectors (low-angle scattering detector and high-angle scattering detector), and the coordinates and sizes of the defects were obtained. That is, a standard wafer of the present invention was prepared (step S1).

[0045] Next, as the particle counter to be managed, the normal SP7 used in the S1 process was used. XP Different from SP7 XP Measurement was performed in oblique mode / 15 nm up using a detector (low-angle scattering detector and high-angle scattering detector) to detect scattered light generated by defects present on the top surface of the standard wafer, and the coordinates and size of the defects were obtained (S2 process).

[0046] Next, the coordinates of the defects detected in steps S1 and S2 were compared, and the difference in the detection size of defects detected at the same coordinates (values ​​calculated using calculation formulas L and H) was calculated for each detector (step S3). Then, a frequency distribution curve was created for the large number of detected size differences thus obtained, and the absolute value of the most frequent value was obtained for each detector (step S4). The absolute value of the most frequent size difference for the low-angle scattering detector was 0 nm, while the absolute value of the most frequent size difference for the high-angle scattering detector was 4 nm. Because the absolute value of the most frequent size difference for the low-angle detector was greater than the absolute value of the most frequent size difference for the high-angle scattering detector, it was determined that there was an abnormality in the optical system. An inspection of the equipment revealed a malfunction in the optical system of the high-angle scattering detector. Therefore, the optical system of this high-angle scattering detector was calibrated (Step S5).

[0047] For confirmation, the optical system of the low-angle scattering detector was also inspected, but no defects were found. In this way, the management method of the present invention was able to detect an abnormality only in the high-angle scattering detector.

[0048] (Comparative Example) Using a conventional standard wafer, we verify whether or not an abnormality can be detected only in the high-angle scattering detector of the particle counter (in the state before calibration in step S5 of the embodiment) that was the object of control in the embodiment. More specifically, as described below, the same steps as in the embodiment are carried out except that a conventional standard wafer is used.

[0049] First, we prepared a silicon wafer coated with 32 to 100 nm of silica as a standard wafer. We confirmed that this silica was spherical (conventional standard wafer). Next, the SP7 particle counter is used to measure the particle size. XP (i.e., using a normal surface defect inspection device also used in the examples), measurements were performed in oblique mode / 15 nm up, and scattered light generated by defects present on the outermost surface of the standard wafer was detected with detectors (low-angle scattering detector and high-angle scattering detector), and the coordinates and size of the defects were obtained (Process A: corresponds to Process S1 of the present invention, except that a conventional standard wafer was used).

[0050] Next, as a particle counter to be managed, SP7, which was evaluated in the example and found to have an abnormality in the optical system of the high-angle scattering detector, XP Measurement was performed in oblique mode / 15 nm up using a standard wafer (before calibration in the example), and scattered light generated by defects present on the top surface of the standard wafer was detected with detectors (low-angle scattering detector and high-angle scattering detector), and the coordinates and size of the defects were obtained (step B: corresponding to step S2 of the present invention).

[0051] Next, the coordinates of the defects detected in the A step and the B step were compared, and the difference in the detected size of the defects detected at the same coordinates was calculated for each detector (C step: corresponding to S3 step of the present invention). Then, a frequency distribution curve was created for the large number of detected size differences thus obtained, and the absolute value of the most frequent value was obtained for each detector (step D: corresponding to step S4 of the present invention). The most frequent value of the difference in detected size for all detectors was 0 nm. Therefore, although the particle counter actually had an abnormality only in the high-angle scattering detector, as verified in the example, the control method of this comparative example using a conventional standard wafer could not detect an abnormality in the optical system because the difference in detected size between the low-angle detector and the high-angle detector was the same (Process E: corresponding to Process S5 of the present invention).

[0052] Table 1 shows the absolute values ​​of the most frequent values ​​of the difference in detected size in the high-angle scattering detector and the low-angle scattering detector for the examples and comparative examples, as well as the magnitude relationship between them (absolute value of the difference in detected size in the high-angle scattering detector - absolute value of the difference in detected size in the low-angle scattering detector). As described above, in the examples implementing the present invention, it was possible to detect anomalies in only the high-angle scattering detector from the absolute value of the most frequent value of the difference in detected size, and appropriate inspection and calibration could be performed, but the conventional method using a standard wafer was not able to detect anomalies in only the high-angle scattering detector.

[0053] [Table 1]

[0054] The present specification includes the following aspects. [1]: A method for managing a surface defect inspection device that inspects surface defects of semiconductor silicon wafers, the device being equipped with a high-angle scattering detector and a low-angle scattering detector having a detection angle lower than that of the high-angle scattering detector, the method comprising: a standard wafer preparation step of preparing, as a standard wafer for managing the surface defect inspection device, a semiconductor silicon wafer having a convex or concave shape whose dimension parallel to the wafer surface is greater than the dimension perpendicular to the wafer surface and on whose outermost surface a plurality of defects whose coordinates and sizes are known are formed; a defect detection step of irradiating a laser onto the surface of the standard wafer using a surface defect inspection device to be managed, detecting scattered light generated by defects present on the outermost surface of the standard wafer with the detector, and acquiring coordinates and sizes of the defects; a size shift calculation step of comparing known coordinates of defects on the standard wafer with coordinates of defects detected in the defect detection step, and calculating, for each detector, a detected size difference that is a difference between the known size on the standard wafer and the size detected in the defect detection step, for defects at the same coordinates; a mode acquiring step of acquiring, for each detector, the absolute value of the mode of the detected size difference from the calculated detected size difference; an inspection and calibration step of inspecting and calibrating an optical system of the surface defect inspection device when the absolute value of the most frequent value of the detected size difference in the high-angle scattering detector is greater than the absolute value of the most frequent value of the detected size difference in the low-angle scattering detector; A method for managing a surface defect inspection apparatus having the above-mentioned features. [2]: When the absolute value of the mode of the detected size difference is acquired in the mode acquisition step, The method for managing a surface defect inspection device according to [1] above, wherein a frequency distribution curve of the detected size differences is created and acquired. [3]: In the standard wafer preparation step, when preparing the standard wafer, The method for managing a surface defect inspection device according to [1] or [2] above, wherein a semiconductor silicon wafer on which pits or PIDs are formed as the defects is prepared. [4]: In the standard wafer preparation step, when preparing the standard wafer, The method for managing a surface defect inspection device according to any one of [1] to [3] above, wherein a semiconductor silicon wafer is prepared in which defects having a size of 100 nm or less are formed as the defects. [5]: A standard wafer for controlling surface defect inspection equipment, A standard wafer is a semiconductor silicon wafer having a plurality of convex or concave defects formed on the outermost surface, the dimension of which in a direction parallel to the wafer surface is greater than the dimension of which in a direction perpendicular to the wafer surface. [6]: The standard wafer according to [5] above, wherein the defects are pits or PIDs. [7]: The standard wafer according to [5] or [6] above, wherein the defects are 100 nm or less in size.

[0055] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and that provides similar effects is included within the technical scope of the present invention.

Claims

1. A method for managing a surface defect inspection device that inspects surface defects of semiconductor silicon wafers and is equipped with a high-angle scattering detector and a low-angle scattering detector having a detection angle lower than that of the high-angle scattering detector as detectors, the method comprising: a standard wafer preparation step of preparing, as a standard wafer for managing the surface defect inspection device, a semiconductor silicon wafer having a convex or concave shape whose dimension parallel to the wafer surface is greater than the dimension perpendicular to the wafer surface and on whose outermost surface a plurality of defects whose coordinates and sizes are known are formed; a defect detection step of irradiating a laser onto the surface of the standard wafer using a surface defect inspection device to be managed, detecting scattered light generated by defects present on the outermost surface of the standard wafer with the detector, and acquiring coordinates and sizes of the defects; a size shift calculation step of comparing known coordinates of defects on the standard wafer with coordinates of defects detected in the defect detection step, and calculating, for each detector, a detected size difference that is a difference between the known size on the standard wafer and the size detected in the defect detection step, for defects at the same coordinates; a mode acquiring step of acquiring, for each detector, the absolute value of the mode of the detected size difference from the calculated detected size difference; an inspection and calibration step of inspecting and calibrating an optical system of the surface defect inspection device when the absolute value of the most frequent value of the detected size difference in the high-angle scattering detector is greater than the absolute value of the most frequent value of the detected size difference in the low-angle scattering detector; 1. A method for managing a surface defect inspection device, comprising:

2. When acquiring the absolute value of the most frequent value of the detected size difference in the mode acquisition step, 2. The method for managing a surface defect inspection apparatus according to claim 1, further comprising the step of creating and acquiring a frequency distribution curve of the detected size difference.

3. In the standard wafer preparation step, when preparing the standard wafer, 2. The method for managing a surface defect inspection device according to claim 1, further comprising the step of preparing a semiconductor silicon wafer on which pits or PIDs are formed as the defects.

4. In the standard wafer preparation step, when preparing the standard wafer, 3. The method for managing a surface defect inspection device according to claim 2, further comprising the step of preparing a semiconductor silicon wafer on which pits or PIDs are formed as the defects.

5. In the standard wafer preparation step, when preparing the standard wafer, 5. The method for managing a surface defect inspection device according to claim 1, wherein a semiconductor silicon wafer is prepared in which defects having a size of 100 nm or less are formed as the defects.

6. A standard wafer for managing a surface defect inspection device, A standard wafer is a semiconductor silicon wafer having a plurality of convex or concave defects formed on its outermost surface, the dimension of which in a direction parallel to the wafer surface is greater than the dimension of which in a direction perpendicular to the wafer surface.

7. 7. The standard wafer according to claim 6, wherein the defect is a pit or a PID.

8. 8. The standard wafer according to claim 6, wherein the defects have a size of 100 nm or less.

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