Defect inspection system

Abstract

In order to accurately correct positional deviation due to vibration even in a state in which defect inspection is being performed under various inspection modes (inspection conditions), the present disclosure proposes a defect inspection system comprising (i) a lighting detection unit having a light source that irradiates a sample with light, and a detector that detects light from the sample, (ii) a stage mechanism for holding the sample that includes a rectilinear stage and a rotary stage, position sensors that measure the position of the rectilinear stage and the rotary stage, and an accelerometer for measuring the vibration of the rectilinear stage and the rotary stage, and (iii) a control unit for obtaining defect coordinates indicating the position of a defect on the basis of measurement values from the position sensors, wherein (iv) the control unit compares an output reference model of the accelerometer that has been calculated in advance in accordance with an inspection mode defining a sample inspection method, with a value actually measured by the accelerometer during the inspection of the sample in accordance with the inspection mode, to determine a mechanical positional deviation amount in the stage mechanism, and corrects the defect coordinates using the mechanical positional deviation amount (see Fig. 6).

Description

Defect Inspection System

[0001] The present disclosure relates to defect inspection systems.

[0002] In the semiconductor manufacturing process, defects (scratches, foreign particles, etc.) on samples have a large impact on yield, and it is important for yield management to feed back defect inspection information from defect inspection systems to the semiconductor manufacturing process and manufacturing equipment. For this reason, defect inspection systems that perform in-line inspection of samples such as wafers play a major role in the semiconductor manufacturing process.

[0003] Regarding defect inspection, for example, Patent Document 1 discloses a defect inspection device that detects defects by spirally scanning an illumination spot (the illumination light irradiation position) on the surface of a semiconductor wafer by combining a rotational movement θ as a main scan and a linear (translational) movement R as a sub-scan. Patent Document 1 also discloses that the defect inspection device operates in multiple different inspection modes, such as a defect inspection mode using CAV (Constant Angular Velocity) scanning, a CLV (Constant Linear Velocity) scanning, and an acceleration / deceleration inspection in which inspection is performed even during acceleration or deceleration of the rotation of the sample stage. In each inspection mode, the irradiation speed and the resulting irradiation amount per inspection point change in regions of different radial distances during the inspection process of a circular sample, such as a semiconductor wafer, by rotationally scanning the sample from the inner circumference to the outer circumference or from the outer circumference to the inner circumference.

[0004] International Publication No. 2021 / 014623

[0005] Defect inspection systems are constantly required to improve their inspection sensitivity and throughput. However, there is a trade-off between sensitivity and throughput. The acceleration / deceleration inspection disclosed in Patent Document 1 is a mode that shortens the total inspection time by utilizing a portion of the time during which no inspection was performed, during which the stage is accelerating or decelerating to a certain speed, as inspection time. Therefore, it is a very useful means for improving throughput.

[0006] On the other hand, the acceleration / deceleration inspection mode has the aspect of being difficult to control. This is because, compared to when the stage is rotated at a constant speed and then the sample is inspected, the vibrations associated with the illumination beam irradiating the sample, the stage, and the entire apparatus become more complex during inspection during acceleration or deceleration. In particular, in a defect inspection apparatus that uses multiple inspection modes, such as CAV (Constant Angular Velocity) scanning and CLV (Constant Linear Velocity) scanning, as described in Patent Document 1, the tendency of vibrations changes depending on the mode.

[0007] However, in the technology disclosed in Patent Document 1, it is desirable to take measures against the effects of vibrations caused by different inspection modes. Such vibrations affect the accuracy of defect coordinates output by the defect inspection system. Particularly when the sample is a semiconductor wafer, the size of defects to be detected is becoming smaller as semiconductor patterns become finer. Defect images are confirmed by the defect inspection system outputting the presence or absence of defects and their coordinates, which are then confirmed by a review SEM based on those coordinates. In this case, if there is a deviation in the defect coordinates output by the defect inspection system, it takes a long time to find the defect using the review SEM, preventing improvement in throughput. In particular, the smaller the defect size to be confirmed, the more difficult it becomes to identify the defect position during subsequent observation using the review SEM, even with a slight coordinate deviation. Thus, coordinate deviations caused by various vibrations within the defect inspection system are becoming less acceptable in the semiconductor industry. Therefore, a means is needed to accurately correct the output defect coordinates even when multiple inspection modes are used.

[0008] In view of such circumstances, the present disclosure proposes a technique for accurately correcting positional deviations caused by vibrations even when defect inspection is being performed in various inspection modes (inspection conditions).

[0009] In order to solve the above problems, the present disclosure provides a defect inspection system for inspecting defects in a sample, comprising: (i) an illumination and detection unit having a light source that irradiates light onto the sample and a detector that detects light from the sample; (ii) a stage mechanism that holds the sample and has a linear stage and a rotational stage, a position sensor that measures the positions of the linear stage and the rotational stage, and an accelerometer that measures vibrations of the linear stage and the rotational stage; and (iii) a control unit that determines defect coordinates that indicate the position of the defect based on measurements by the position sensor, wherein (iv) the control unit compares an output reference model of the accelerometer that is calculated in advance according to an inspection mode that specifies the inspection method of the sample with a value actually measured by the accelerometer during inspection of the sample according to the inspection mode to determine the amount of mechanical positional deviation in the stage mechanism, and corrects the defect coordinates using the amount of mechanical positional deviation.

[0010] Further features related to the present disclosure will become apparent from the description of this specification and the accompanying drawings. Also, aspects of the present disclosure are achieved and realized by the elements and combinations of various elements and the aspects of the following detailed description and the appended claims. The description of this specification is merely exemplary and does not limit the scope or application of the claims of the present disclosure in any way.

[0011] According to the technology of the present disclosure, it is possible to accurately correct positional deviations due to vibrations even when defect inspection is being performed in various inspection modes (inspection conditions).

[0012] FIG. 1 is a diagram illustrating an example of the basic configuration of a defect inspection apparatus 100. FIG. 2 is a diagram for explaining the incident direction of illumination light and the feed direction of a sample by the defect inspection apparatus. FIG. 3 is a schematic diagram illustrating the movement path of a sample 1 inside the defect inspection apparatus 100. FIG. 4 is a plan view of a sample, schematically illustrating the scanning trajectory of the sample by the defect inspection apparatus 100. FIG. 5 is a diagram illustrating an example of the hardware configuration of a defect detection processing system 40. FIG. 6 is a schematic diagram for explaining optical vibration and mechanical vibration in the defect inspection apparatus 100. FIG. 7 is a flowchart for explaining processing executed by the defect detection processing system 40. FIG. 8 is a diagram illustrating an example of a defect coordinate shift on a wafer. FIG. 9 is a diagram illustrating an example of the trajectory of an illumination light spot S10 irradiated on the sample 1 and a scanning line. FIG. 10 is a diagram illustrating an example of the trajectory of an illumination light spot S20 on the light beam position sensor 50 (beam spot change on the light beam position sensor). FIG. 11 is a diagram illustrating an example of the position of a defect when there is no mechanical vibration. FIG. 12 is a diagram illustrating an example of the position of a defect when there is mechanical vibration. FIG. 13 is a diagram illustrating the speed change of a linear stage during CAV scanning. FIG. 14 is a diagram illustrating the output change of an acceleration sensor 70 (in one axial direction) during CAV scanning. FIG. 10 is a diagram showing changes in output of the displacement sensor 60 (in one axial direction) during CAV scanning.

[0013] An embodiment of the present disclosure relates to a defect inspection system that inspects a sample such as a wafer for defects. The embodiment discloses a technique for correcting a deviation amount of a defect coordinate in the defect inspection system, taking into account both mechanical vibrations caused by vibrations of a stage on which the sample is placed and optical vibrations caused by fluctuations of a laser beam in an illumination system, even if the inspection mode (CAV, CLV, acceleration / deceleration inspection mode, etc.) is different.

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the accompanying drawings, functionally identical elements may be designated by the same numerals. Note that the accompanying drawings illustrate specific embodiments and implementation examples according to the principles of the present disclosure, but these are for understanding the present disclosure and are not to be used to interpret the present disclosure in any way as being limiting.

[0015] Furthermore, although the present embodiment has been described in sufficient detail to enable those skilled in the art to implement the present disclosure, it should be understood that other implementations and forms are possible, and that changes to the configuration and structure and substitutions of various elements are possible without departing from the scope and spirit of the technical ideas of the present disclosure. Therefore, the following description should not be interpreted as being limited thereto.

[0016] <Configuration Example of Defect Inspection Apparatus> Here, we will explain the basic configuration of a defect inspection apparatus (defect inspection system) 100. For simplicity, we will first explain the configuration of the parts excluding the mechanical and optical vibration correction functions.

[0017] FIG. 1 is a diagram showing an example of the basic configuration of a defect inspection apparatus 100. The defect inspection apparatus 100 shown in FIG. 1 is a system in which an illumination light I1 is irradiated onto a sample 1 that moves linearly while rotating, and the sample 1 is scanned spirally or concentrically to inspect defects in the sample 1. The sample 1 can be, for example, a circular plate-shaped object such as a wafer (including wafers at various stages of a semiconductor manufacturing process, such as bare wafers, film-covered wafers, and patterned wafers). However, semiconductor device substrates other than wafers may also be used, and the sample 1 is not limited to wafers. Furthermore, defects detected by inspection include scratches and undulations on the sample 1, foreign matter attached to the sample 1, and the like.

[0018] The defect inspection apparatus 100 basically comprises a stage device 10, an illumination and detection unit 20, a vibration isolation mount 14, and a defect detection processing system 40 that includes a data processing circuit (not shown) and a stage control circuit (not shown). These elements will be described in order.

[0019] (i) Stage Device The stage device 10 is a rotary / linear stage capable of rotary and linear (translational) motion. The stage device 10 includes a sample stage 11, a rotary stage 12, and a linear stage 13. The stage device 10, together with the illumination and detection unit 20, is mounted on a vibration isolation mount 14 to reduce external vibrations from other units both inside and outside the device.

[0020] The sample stage 11 is a stage that holds the sample 1, such as a wafer, horizontally. The sample stage 11 can be of various types, including a type that holds the sample 1 by suction on the backside of the sample 1 (disclosed, for example, in Japanese Patent Application Laid-Open No. 11-233597), and a type that holds the sample 1 in a state where the backside is raised by gripping the edge of the sample. A sample stage that suctions the backside of the sample 1 is used, for example, when the defect inspection system 100 is used by semiconductor device manufacturers. A sample stage that holds the sample 1 by raising the backside is used, for example, when the defect inspection system 100 is used by wafer manufacturers that do not allow the backside of the sample 1 to contact the sample stage. Sample stages that hold the sample 1 by raising the backside include, for example, a type that holds the outer periphery of the sample 1 with a clamp CL (see FIG. 2), and a type that holds the sample 1 by a pressure member while raising it by air pressure (disclosed, for example, in Japanese Patent Application Laid-Open No. 2017-504199).

[0021] The rotating stage 12 is a stage that supports the sample stage 11. The rotating stage 12 rotates about a vertical rotation axis (not shown) and rotates the sample 1 together with the sample stage 11. The rotating stage 12 is equipped with an optically readable rotary encoder (not shown). The rotary encoder detects the rotation angle (θ coordinate) of the rotating stage 12 and outputs this information to the defect detection processing system 40. However, the detector for detecting the θ coordinate is not limited to a rotary encoder, and any sensor that can accurately detect the rotation angle can be used instead of the rotary encoder.

[0022] The linear stage 13 is a stage that supports the rotary stage 12. The linear stage 13 moves along rails (not shown) that extend in the radial direction (R-axis direction) of the rotary stage 12, and moves the sample 1 horizontally and linearly together with the rotary stage 12 and the sample stage 11. The linear stage 13 is equipped with an optically readable linear encoder (not shown). The linear encoder detects the position on the R-axis (R coordinate) of the linear stage 13 and outputs this information to the defect detection processing system 40. However, the detector for detecting the R coordinate is not limited to a linear encoder, and any sensor that can accurately detect a position on a straight line can be used instead of the linear encoder.

[0023] FIG. 3 is a schematic diagram showing the movement path of the sample 1 inside the defect inspection apparatus 100. In this embodiment, as shown in FIG. 3, a sample transfer position P1 and a scan start position P2 are set on the R axis, which is the linear trajectory of the linear stage 13. A stage control circuit (not shown) in the defect detection processing system 40 is configured to drive the linear stage 13 to move the rotation stage 12 along a line including the sample transfer position P1 and the scan start position P2. The scan start position P2 is the position where the illumination light I1 is irradiated onto the sample 1 and scanning of the sample 1 begins. Specifically, the scan start position P2 is the position where a specific point on the sample 1 (center O in this embodiment ( FIG. 4 )) coincides with the illumination light spot (the focal position of the illumination light I1) of the illumination and detection unit 20. The other sample transfer position P1 is the position where the sample 1 starts moving to the scan start position P2. The sample transfer position P1 also serves as a position where the sample 1 is loaded and unloaded onto and from the sample stage 11 by, for example, a transport arm Am (FIG. 3). This sample transfer position P1 is separated from the illumination light spot. In this embodiment, the distance between the sample transfer position P1 and the scan start position P2 is approximately 150 mm to 500 mm. Position P3 indicates the position when the peripheral portion of the sample 1 is scanned (sample peripheral portion scanning position).

[0024] (ii) Illumination and Detection Unit The illumination and detection unit 20 includes an illumination optical system 21 and a detection optical system 25. The illumination optical system 21 is an optical system that irradiates the sample 1 with illumination light I1 and includes an illumination light source (e.g., a laser light source) 22 and multiple optical elements 23. The detection optical system 25 is an optical system that detects the inspection light I2 scattered or reflected by the sample 1 and includes a condensing optical element (condensing lens) 26, a photodetector 27, and a detection circuit 28. Since high inspection sensitivity is required, the illumination and detection unit 20 is located close to the sample 1 ( FIG. 3 ). When the sample stage 11 is located directly below the illumination and detection unit 20, the gap G between the sample stage 11 and the illumination and detection unit 20 is several mm or less. The defect inspection apparatus 100 of this embodiment is configured so that the distance between the illumination and detection unit 20 (the lowest optical element) and the sample 1 is 0.5 mm to 5 mm or less in order to widely introduce illumination light into the detector. Since it is difficult to transport the sample 1 by the transport arm Am and insert it into this gap G to place it on the sample stage 11, a sample transfer position P1 is provided as shown in FIG.

[0025] In this embodiment, the illumination optical system 21 is installed on the opposite side of the scan start position P2 from the sample transfer position P1. Therefore, the illumination light I1 is obliquely irradiated onto the sample 1 from the opposite side of the sample transfer position P1 (see FIG. 3). The oblique irradiation configuration is adopted in order to position the illumination optical system 21 so as to avoid the work space for loading and unloading the sample 1 and to reduce the distance between the sample transfer position P1 and the scan start position P2. The illumination light source 22 is provided with a shutter (not shown) and is configured to irradiate the illumination light I1 onto the sample 1 or block the illumination light I1 by opening and closing the shutter.

[0026] FIG. 4 is a plan view of a sample, schematically illustrating the scanning trajectory of the sample by the defect inspection apparatus 100. When the shutter of the illumination light source 22 opens, illumination light I1 emitted from the illumination light source 22 is irradiated onto the sample 1 via multiple optical elements 23. By rotating and translating the sample 1 held by the stage device 10, the illumination light I1 is irradiated along a spiral trajectory (scanning pitch: p0) from the center O of the sample 1 to its outer edge, as shown in FIG. 4, and the entire surface of the sample 1 is scanned. The inspection light I2 scattered or reflected by the sample 1 is detected via a focusing optical element (focusing lens) 26, a photodetector (e.g., a photoelectric sensor) 27, and a detection circuit 28. The detection circuit 28 outputs the detection results to a data processing circuit (not shown) in the defect detection processing system 40.

[0027] The defect detection processing system 40 is programmed to drive the linear stage 13 from the scan start position P2 in a direction approaching the illumination optical system 21 during defect inspection. That is, in the present embodiment, the illumination optical system 21 is disposed on the opposite side of the sample transfer position P1. Therefore, during sample scanning, the movement of the linear stage 13 is controlled in a direction away from the sample transfer position P1, starting from the scan start position P2. As a result, even when a configuration is adopted in which the sample 1 is held by multiple clamps CL as the sample stage 11, as illustrated in FIG. 2, for example, scanning from the center O to the outer edge of the sample 1 is possible while avoiding interference between the illumination light I1 and the clamps.

[0028] That is, because the angle of incidence of the illumination light I1 on the sample 1 (the angle it makes with respect to the vertical) is large, if the illumination light I1 is irradiated from the sample transfer position P1 side as shown by the two-dot chain line in Figure 2, the light will be blocked by the clamp CL toward the end of the scan, making it impossible to adequately inspect the outer periphery of the sample 1. Furthermore, even if the arrangement of the illumination optical system 21 and the feed direction of the linear stage 13 during scanning are the same as in this embodiment, if scanning is started from the outer periphery of the sample 1 (scan start position P2 is set at the outer edge of the sample 1), a similar problem will arise at the beginning of the scan. In contrast, this embodiment is configured so that, even when using a sample stage 11 equipped with a clamp CL, for example, interference between the illumination light I1 and the clamp CL can be avoided from the start to the end of the scan, allowing the entire surface of the sample 1 to be inspected.

[0029] Although FIG. 3 shows the case where the laser light is irradiated obliquely, other light sources such as a broadband light source can also be used as the illumination light source 22, and the arrangement of the light source and the stage and the direction of irradiation from the light source to the sample may differ depending on the type of light source.

[0030] (iii) Defect Detection Processing System The defect detection processing system 40 is equipped with an internal data processing circuit (not shown). The data processing circuit generates scan information (inspection results) from the detection results from the illumination and detection unit 20 and the Rθ coordinates output from the stage device 10. The scan information generated by the data processing circuit includes the positions of defects such as foreign matter and scratches, and the size and shape of the defects based on the amount of detection signals.

[0031] The defect detection processing system 40 is further equipped with a stage control circuit (not shown). This stage control circuit is a circuit that controls the operation of the stage device 10. The stage control circuit can be composed of, for example, a motor driver that drives the drive device (motor) of the rotary stage 12 and a motor driver that drives the drive device (motor) of the linear stage 13. In the defect detection processing system 40, the stage control circuit drives the drive device based on command values ​​regarding the operation of the stage device 10. This causes the rotary stage 12 and the linear stage 13 to operate.

[0032] 5 is a diagram showing an example of the hardware configuration of the defect detection processing system 40. The defect detection processing system 40 is a computer that controls the operations of the illumination detection unit 20, the rotary stage 12, and the linear stage 13 (stage device 10), etc. The defect detection processing system 40 includes, for example, an input interface 41, a ROM (e.g., an EPROM) 42, a RAM 43, a CPU 44, a timer 45, an output interface 46, etc.

[0033] The input interface 41 transfers to the CPU 44 signals (R and θ coordinates of the sample stage 11) from the encoders of the rotary stage 12 and the linear stage 13, as well as inspection conditions input from an input device (not shown) such as a keyboard in response to operator operation. The inspection conditions include, for example, the type, size, and shape of the sample 1, as well as information on the inspection mode. The ROM 42 stores arithmetic expressions, programs (described below), and data required for defect inspection. The RAM 43 stores numerical values ​​during calculations and information such as inspection conditions input from the input device. The output interface 46 outputs command signals to the stage device 10 and the illumination detection unit 20 in response to commands from the CPU 44. The defect detection processing system 40 also outputs coordinate detection signals of the rotary stage 12 and the linear stage 13 (calculated R and θ coordinates of the sample stage 11) to a data processing circuit (not shown) via the output interface 46.

[0034] The CPU 44 executes predetermined processing based on the information input via the input interface 41 in accordance with the program loaded from the ROM 42. The stage device 10 and the illumination and detection unit 20 are also controlled by command values ​​output from the CPU 44 based on the inspection conditions, the Rθ coordinate of the sample stage 11 to be measured, and the like, and the sample 1 is scanned in this way.

[0035] <Inspection Modes> The defect inspection apparatus 100 can operate in multiple inspection modes, such as CAV (Constant Angular Velocity) inspection, CLV (Constant Linear Velocity) inspection, and acceleration / deceleration inspection. CAV inspection is an inspection mode in which the rotational speed (angular velocity) of the rotating stage 12 during scanning is kept constant. CLV inspection is an inspection mode in which the linear velocity (scanning speed) is kept constant.

[0036] Acceleration / deceleration inspection is an inspection mode in which inspection is performed even during acceleration and deceleration. "During acceleration" means that the inspection does not start once the predetermined stage rotation speed is reached, but rather starts during the acceleration process until the predetermined stage rotation speed is reached. "During deceleration" means that, while inspection is usually completed at the predetermined stage rotation speed and then the stage rotation is decelerated and stopped, the inspection continues partway through the deceleration process of the rotation speed and ends during deceleration.

[0037] Here, the acceleration / deceleration inspection mode will be explained in detail. In a stage device 10 with large inertia, it takes longer to increase the rotational speed of a stationary stage to the specified rotational speed (or to stop a sample stage rotating at the specified rotational speed) than to move linearly between the sample delivery position P1 and the scan start position P2. Therefore, when the sample stage 11 moves linearly from the sample delivery position P1 and arrives at the scan start position P2, the stage rotational speed does not reach the specified rotational speed. Increasing the specified rotational speed in response to a user request increases the time required for rotational acceleration / deceleration. On the other hand, shortening the movement distance shortens the movement time. In this case, the time difference between the time required for rotational acceleration / deceleration and the time required for stage movement becomes increasingly large. If scanning is initiated with the stage rotating at the specified rotational speed as usual, there will be a wait time at the scan start position P2 for the rotational speed to reach the specified rotational speed. When returning the sample stage 11 to the sample delivery position P1 after scanning, there may also be a wait time for the sample stage 11 to stop rotating at the sample delivery position P1. If the specified rotation speed increases and the movement distance decreases, the overall inspection processing time can be expected to be reduced by reducing the scanning time and movement time, but on the other hand, the proportion of waiting time in the inspection processing time increases due to the increase in the time difference between the time required for rotation acceleration and the time required for movement.

[0038] Therefore, when the sample reaches the scanning position, scanning begins without waiting for the specified rotation speed to be reached. In other words, this is an inspection method that reduces the distance between the sample (e.g., a wafer) and the optical system (illumination and detection unit) to achieve high sensitivity, thereby reducing the waiting time associated with acceleration and deceleration of stage rotation, particularly acceleration, when moving the stage between the sample transfer position P1 and the scan start position P2. In this inspection method, the net irradiation time can be maximized within the specified sequence by devising control over the linear velocity and angular velocity of the stage (described below).

[0039] The defect inspection apparatus 100 can use different inspection modes, such as CAV inspection, CLV inspection, and acceleration / deceleration inspection, depending on the user's application and needs. However, because the defect inspection apparatus 100 has different inspection modes, control corresponding to each inspection mode is required in controlling the illumination and detection unit 20 and the stage device 10, which makes the control method complicated.

[0040] The need for highly accurate control for each inspection mode is driven by the industry trend of increasingly miniaturized and complex semiconductor devices. As semiconductor devices become smaller, the size of defects to be detected becomes smaller, requiring increasingly accurate coordinates. Even in the defect inspection apparatus 100 according to this embodiment, misalignment occurs when calculating defect coordinates. For example, misalignment can be caused by optical vibrations and mechanical vibrations. Such vibration-induced misalignment was previously considered tolerable and very small. However, as semiconductor devices themselves become increasingly miniaturized and the size of defects to be detected becomes even smaller, the impact of such vibration-induced misalignment on coordinate accuracy becomes relatively greater. As a result, even very small misalignment is no longer acceptable for the defect coordinate accuracy desired by users.

[0041] <Correction of Position Misalignment Due to Optical and Mechanical Vibrations> FIG. 6 is a schematic diagram illustrating optical and mechanical vibrations in the defect inspection apparatus 100. As shown in FIG. 6, optical vibrations are caused by fluctuations in the illumination light I1 from the illumination optical system 21. The fluctuations in the illumination light I1 are caused by vibrations of the optical element 23 (mechanical vibrations of the stage device 10 are also a factor), air vibrations, and / or the external environment (temperature and humidity). In particular, because the motion of the crystal inside the illumination light source (laser light source) 22 fluctuates depending on temperature, it is almost impossible to irradiate the illumination light I1 (laser light) at a single point (the irradiation position is not fixed at a single point). On the other hand, mechanical vibrations are caused by fluctuations in the rotation stage 12 and the linear (translation) stage 13 of the stage device 10.

[0042] In the defect inspection apparatus 100, the detection optical system 25 detects the inspection light I2 scattered or reflected by the sample 1. The defect detection processing system 40 then calculates defect coordinates based on the detection signal and the Rθ coordinates output from the stage device 10. At this time, correction is required to take into account the amount of deviation in coordinate information caused by optical vibrations and mechanical vibrations relative to the coordinates where the defect actually exists. Note that, while conventional attempts have been made to eliminate the effects of vibration using only the vibration isolation mount 14, this embodiment measures the amount of positional deviation caused by vibrations (fine vibrations) that cannot be completely eliminated by the vibration isolation mount 14, and reflects this amount of positional deviation in the measured defect coordinates based on signal processing.

[0043] (i) Measurement of Positional Misalignment Due to Optical Vibrations on the Illumination Optical System 21 Side As shown in FIG. 6 , the light beam position sensor 50 is installed on the illumination optical path from the illumination light source 22 to the sample 1 (on an extension of a portion of the illumination optical path). It is preferable to install the light beam position sensor 50 as late as possible in the illumination optical path. This is because it is difficult to accurately measure positional misalignment caused by vibrations of the optical elements 23 and other components downstream of the light beam position sensor. Furthermore, the light irradiating the light beam position sensor 50 must be adjusted so that it is centered on the light beam position sensor 50. For example, a reflective or transmissive optical element can be placed on the illumination optical path, and the optical path can be adjusted using this optical element so that the inspection light is centered on the light beam position sensor 50. As a result, even during actual inspection, the beam should ideally enter the center of the light beam position sensor 50, but the beam inevitably wobbles as it travels along the optical path. Therefore, during actual inspection, the illumination light I11 entering the light beam position sensor 50 is slightly offset from the center. The light beam position sensor 50 detects the actual incident position. The difference between the actual incident position and the center point as the reference position can be used as the "position deviation amount" output by the light beam position sensor 50. Alternatively, a beam splitter may be used to extract a portion of the light and make it incident on the light beam position sensor 50. The light beam position sensor 50 must be capable of measuring deviation amounts in both the angle and position of the illumination light I1, or at least two sensors capable of measuring position deviation must be installed on the optical path. This allows the position of the laser beam to be measured constantly. When two sensors are installed, the angle of the laser beam can be calculated from the laser beam positions detected by each sensor.

[0044] (ii) Measurement of deviation due to mechanical vibration on the stage device 10 side As shown in Figure 6, a displacement sensor 60 is mounted on the stage device 10, for example, on the linear stage 13, on a vibration isolation mount 14. An acceleration sensor 70 is mounted on the rotation stage 12 and measures the amount of positional deviation in the R-axis direction and the θ-axis direction. The vibration isolation mount 14 structurally reduces disturbance vibrations from other units outside and inside the device (it directly attenuates vibrations as a physical quantity (not by data processing)).

[0045] The displacement sensor 60 detects low-frequency external vibrations that cannot be removed by the vibration isolation mount 14. Examples of external vibrations include vibrations from the floor of a factory or other facility where the defect inspection device 100 is installed, vibrations caused by the influence of vibrations from nearby devices, and vibrations caused by fans or the like within the device. Meanwhile, the acceleration sensor 70 detects high-frequency vibrations, such as vibrations caused by the rotation of the rotating stage 12, vibrations caused by accelerating or decelerating the rotation, and vibrations caused by imbalance of a rotating body. Generally, the displacement sensor 60 is highly sensitive to low-frequency vibrations, while the acceleration sensor 70 is highly sensitive to measuring vibrations in the high-frequency range. The sum of the displacement amounts due to low-frequency and high-frequency vibrations output by these sensors can be used as the "position deviation amount" due to mechanical vibrations.

[0046] In this way, optical vibrations caused by fluctuations in the illumination light I1 are detected by the light beam position sensor 50, and mechanical vibrations caused by shaking acting on the stage device 10 are detected by the displacement sensor 60 and acceleration sensor .

[0047] <Processing Contents in Defect Detection Processing System 40> FIG. 7 is a flowchart for explaining the processing executed by the defect detection processing system 40. As shown in FIG.

[0048] (i) S701 The defect detection processing system 40 detects defects from the inspection light I2 signal detected via the photodetector (e.g., photoelectric sensor) 27 and the detection circuit 28, and the stage encoder signals detected by the rotary stage encoder (not shown) and the translation stage encoder (not shown), and calculates the coordinates of the defects. The calculated coordinates include components of positional deviation due to the optical vibration and mechanical vibration described above.

[0049] (ii) S702 The defect detection processing system 40 calculates the amount of positional deviation of the illumination light I12 irradiated onto the sample 1 from the amount of positional deviation of the illumination light I11 detected by the light beam position sensor 50.

[0050] Due to the arrangement of the optical elements and the light beam position sensor 50 in the illumination detection unit 20, the distance from the illumination light source 22 to the light beam position sensor 50 may differ from the distance from the illumination light source 22 to the sample 1 (optical path distance). Therefore, the amount of positional deviation of the illumination light I11 detected by the light beam position sensor 50 differs from the amount of positional deviation of the illumination light I12 on the sample 1. Therefore, in this embodiment, a relative relationship between the amount of positional deviation of the light beam position sensor 50 and the amount of positional deviation of the illumination light I12 on the sample 1 is obtained in advance by measurement, and this relationship is stored (e.g., as a table) in a storage device (not shown) in the defect detection processing system 40. The defect detection processing system 40 may then obtain from the storage device the amount of positional deviation of the illumination light I12 corresponding to the amount of positional deviation of the illumination light I11 detected by the light beam position sensor 50. A detailed example of calculating the amount of optical positional deviation will be described later.

[0051] (iii) S703 In parallel with S702, the defect detection processing system 40 calculates the amount of positional deviation due to mechanical vibration by adding (vector sum) the amount of displacement due to low-frequency vibration detected by the displacement sensor 60 installed on the stage device 10 on the vibration isolation mount 14 and the amount of displacement due to high-frequency vibration detected by the acceleration sensor 70 of the rotation stage 12. A detailed example of calculating the amount of mechanical positional deviation will be described later.

[0052] (iv) S704 The defect detection processing system 40 calculates the coordinate correction amount by vector addition of the positional deviation amount due to optical vibration calculated in S702 and the positional deviation amount due to mechanical vibration calculated in S703.

[0053] (v) S705 The defect detection processing system 40 reflects the coordinate correction amount calculated in S704 to the coordinates calculated in S701, and outputs the presence or absence of a defect in the sample 1 and the coordinate value (correction value) of the defect.

[0054] <Specific Contents of Defect Coordinate Correction> Next, how optical vibration and mechanical vibration affect defect coordinates and how to correct them will be described in detail. Fig. 8 is a diagram showing an example of a defect coordinate shift on a wafer.

[0055] (i) Effects of Optical and Mechanical Vibrations As shown in FIG. 6 , illumination light I12 is irradiated onto the sample 1 on the sample stage 11 on the rotary stage 12 via multiple optical elements 23. For example, the illumination light I12 is first irradiated onto the center position O of the sample 1. Then, in accordance with the movement of the rotary stage 12 and the linear stage 13, the illumination light is irradiated in a spiral pattern from the center to the periphery, as shown in FIG. 8 . Note that this trajectory may also be a spiral trajectory in which the illumination light is irradiated sequentially from the periphery to the center. In this case, the light irradiated onto the sample 1 vibrates due to vibrations of the optical elements 23 on the optical path, changes in temperature and humidity around the illumination optical system 21 in the device, and the like. This causes the illumination position to deviate from the scanning trajectory that should be irradiated by the illumination light. This affects the output defect coordinates and reduces the accuracy of the defect coordinates.

[0056] As described above, mechanical vibrations are generated by shaking of the rotary stage 12 and the linear (translational) stage 13 of the stage device 10. Vibrations are generated simply by moving the linear stage 13 while rotating the rotary stage 12 at high speed. In addition, vibrations generated inside or outside the defect inspection device 100 can be transmitted to the rotary stage 12, causing it to vibrate. These mechanical vibrations can cause the center of the sample 1 (reference value) and the center of the sample stage 11 to shift positions, resulting in a shift in the position of the scanning line as shown in FIG. 8.

[0057] In a defect inspection apparatus 100 having a plurality of different inspection modes, there are factors that further complicate the correction of the positional deviation due to this vibration. For example, different inspection modes (CAV inspection mode, CLV inspection mode, acceleration / deceleration inspection mode, etc.) result in different rotation speeds of the rotary stage 12 and different feed pitches of the linear stage. Furthermore, some inspection modes change the rotation speed and feed pitch during a single inspection. Therefore, the type of vibration and the magnitude and change of the resulting positional deviation are completely different depending on the inspection mode.

[0058] (ii) Introduction of Reference Models In order to accurately calculate the amount of misalignment even when there are differences in the amount of misalignment between the inspection modes, in this embodiment, a reference model for each sensor output is previously established for each inspection mode. For example, FIGS. 11B and 11C are diagrams comparing the reference model (shown by dotted lines) with the outputs of the displacement sensor 60 and acceleration sensor 70 (shown by solid lines) in the acceleration / deceleration inspection mode, which is one of the inspection modes (inspection conditions). The reference displacement and acceleration models represent ideal displacement and acceleration of the rotation stage 12 from the start to the end of the inspection. In contrast, FIGS. 11B and 11C plot the accelerations (measured values) actually detected by the displacement sensor 60 and acceleration sensor 70 attached to the rotation stage 12. This measured acceleration includes the effects of the actual displacement of the seismic isolation mount 14 and mechanical vibrations caused by the acceleration of the rotation stage 12. Therefore, differences arise between the detected values ​​of the displacement sensor 60 and acceleration sensor 70 and the displacement model and the acceleration model. In the acceleration / deceleration inspection mode, an inspection is accelerated at the beginning, rotated at a constant speed in the middle, and decelerated near the end (see FIG. 11A). Therefore, the reference values ​​for the displacement model and acceleration model are different at the beginning, middle, and end of an inspection. For example, assume that defects a, b, and c are located at different radial distances from the center to the periphery, as shown in FIG. 10A. In the case of a spiral scan trajectory from the center of the sample to the periphery, defect a near the center is inspected while the rotating stage is accelerating, defect b while rotating at a constant speed, and defect c while decelerating. The difference between the displacement / acceleration output by the displacement / acceleration sensor when each defect is detected and the displacement / acceleration model is the amount of positional deviation that affects the defect coordinates.

[0059] (iii) Calculation of the amount of positional deviation due to optical vibration and the amount of positional deviation due to mechanical vibration Next, a detailed description will be given of the calculation of the amount of positional deviation due to optical vibration calculated from the output of the light beam position sensor 50, and the amount of positional deviation due to mechanical vibration calculated from the outputs of the acceleration sensor 70 and the displacement sensor 60. When the amount of positional deviation due to optical vibration (assumed to be α) and the amount of positional deviation due to mechanical vibration (assumed to be β) are taken into account, the Cartesian coordinate system (X, Y) with the amount of positional deviation corrected can be expressed by the following equation 1.

[0060] X = α X +β X +R×cosθ Y=α Y +β Y +R×sinθ... (Formula 1)

[0061] where α X is the X-direction component of the positional deviation due to optical vibration, α Y represents the Y-direction component of the positional deviation due to optical vibration. X is the X-direction component of the positional deviation due to mechanical vibration, β Y represents the Y-direction component of the positional deviation caused by mechanical vibration.

[0062] By measuring the positional deviation (α, β), calculating the correction amount, and correcting the coordinate information of the conventional inspection results, more accurate coordinates can be obtained. In this way, the defect detection processing system 40 calculates the coordinate correction amount (vector amount) and corrects the defect coordinates using this.

[0063] (iv) Specific Example of Correction of Positional Deviation Amount Due to Optical Vibration Figures 9A and 9B are diagrams for explaining a specific example of correction of the deviation amount of defect coordinates due to optical vibration. Figure 9A is a diagram showing an example of the illumination light spot S10 irradiated on the sample 1 and the trajectory of the scanning line. Figure 9B is a diagram showing an example of the trajectory of the illumination light spot S20 on the light beam position sensor 50.

[0064] In Figure 9A, S11, S12, and S13 show hypothetical illumination light spots when ideal scanning is performed when there is no influence of optical vibration and the rotation stage 12 and linear stage 13 are not influenced by mechanical vibration and are ideally controlled (in reality, optical vibration and mechanical vibration always occur in the process of irradiating the sample with illumination light).

[0065] When the rotary stage 12 and the linear stage 13 are operated, the illumination light spot S10 (scanning start point (inner circumference of the sample)) scans along a scanning line in a spiral trajectory as shown by S11, S12, and S13 in an ideal state where there is no vibration. Also, as shown in FIG. 9B, in a state where there are no vibrations, the illumination light spot S20 irradiated onto the sensor surface of the light beam position sensor 50 is at the reference position.

[0066] On the other hand, when optical vibrations are present, for example, the illumination light spot S11 vibrates, causing the illumination light spot S12 to be scanned as S12A and the illumination spot S13 to be scanned as S13A, shifting from the scanning line. At this time, the illumination light spot S20 on the light beam position sensor 50 shown in FIG. 9B also shifts from the reference position as S22A and S23A.

[0067] As described above, the illumination light spots S20, S22A, and S23A of the light beam position sensor 50 correlate with the positions of the illumination light spots S10, S11, S12, and S13 irradiated on the sample 1. This correlation is determined in advance by simulation, actual measurement, or the like. The difference between the beam position detected by the light beam position sensor 50 and a reference is determined as the amount of deviation in the light beam position sensor. Then, the amount of positional deviation of the illumination light spots irradiated on the sample 1 is calculated from this amount of deviation and the previously determined correlation.

[0068] Finally, this is linked to coordinate information obtained from the encoder signals of the rotary stage 12 and the linear stage 13. The defect detection processing system 40 performs this series of processes and reflects the amount of deviation due to optical vibration in the defect coordinates. This is coordinate correction for the amount of deviation due to optical vibration.

[0069] (v) Specific Example of Correction of Positional Deviation Amount Due to Mechanical Vibration Figures 10A and 10B are diagrams for explaining a specific example of correction of deviation amount of defect coordinates due to mechanical vibration. Figure 10A is a diagram showing an example of the position of a defect when there is no mechanical vibration. Figure 10B is a diagram showing an example of the position of a defect when there is mechanical vibration.

[0070] Defect coordinates are calculated based on the rotation angle (θ coordinate) and the position on the R axis (R coordinate) obtained from various encoders. Figure 10A shows the coordinates of defects a, b, and c when there is no mechanical vibration. However, during actual inspection, mechanical vibration occurs due to the rotation or translation stage when the inspection begins. As a result, the center position of the sample held on the sample stage 11 shifts (O → O1). Due to the influence of mechanical vibration, the rotation angle and the position on the R axis shift from the center position of the sample 1 (O: the center position of the illumination light spot when there is no mechanical vibration) to the original defect coordinates on the sample 1 (O1: the center position of the illumination light spot when there is mechanical vibration). As a result, the defect coordinates calculated based on the rotation angle (θ coordinate) and the position on the R axis (R coordinate) obtained from various encoders shift from the original coordinates. The defect detection processing system 40 uses the difference (deviation) between the reference model and the actual output of the displacement sensor 60 and the acceleration sensor 70 to correct the deviation.

[0071] Correction of the deviation amount based on the reference model will now be described. FIG. 11A shows the change in velocity of the linear stage during CAV scanning. FIG. 11B shows the change in output of the acceleration sensor 70 (in one axial direction) during CAV scanning. FIG. 11C shows the change in output of the displacement sensor 60 (in one axial direction) during CAV scanning. In FIGS. 11B and 11C, the dotted lines indicate the reference model, which is the ideal output in the absence of mechanical vibration. In addition, in FIGS. 11A to 11C, D1 indicates an inspection mode in which inspection is performed while the rotation stage 12 is rotating at a constant speed (i.e., no inspection is performed during acceleration or deceleration). D2 indicates an inspection mode in which inspection is performed even during acceleration or deceleration of the rotation stage 12. In FIG. 11A, t Ｓ indicates the measurement start timing (time). Ｓ The time until indicates the time period during which the sample 1 is transported from the sample delivery position P1 to the scanning start position P2. Ｅ indicates the timing (time) at which the measurement is completed. Ｅ The time from indicates the time period during which the sample 1 is transported from the scan end position to the sample delivery position P1. Furthermore, as shown by D2 in Figure 11B, the acceleration increases during acceleration / deceleration and becomes zero during uniform motion.

[0072] On the other hand, when mechanical vibrations are present, steady displacement occurs due to external vibrations or vibrations of the rotating stage 12. In particular, during acceleration and deceleration, the displacement increases due to vibrations caused by the inertial force of the stage. Therefore, during acceleration and deceleration inspection, the defect coordinate deviation increases between the inside and outside of the sample 1. The same is true for the rotating stage 12; even at the same rotation speed, vibrations occur due to imbalance in the sample stage 11. The magnitude of vibrations varies depending on the rotation speed of the sample stage 11. Therefore, the amount of displacement due to vibrations also varies depending on the inspection mode and the sample surface. Low-frequency vibrations that cannot be completely removed by the vibration isolation mount 14 are measured by the displacement sensor 60. The low-frequency vibration values ​​are then linked to the rotation angles (θ coordinates) of the rotating stage 12 and the linear stage 13 and their positions on the R axis (R coordinates). Measurement data from the accelerometer is also linked to the rotation angles (θ coordinates) and positions on the R axis (R coordinates). Ultimately, regardless of the inspection mode, the rotation angle (θ coordinate) at which the defect was detected and the amount of central position deviation due to mechanical vibration at the position on the R axis (R coordinate) are calculated from the measurement values ​​(measurement data) of the displacement sensor and acceleration sensor, and the defect coordinates are corrected.

[0073] <Summary> (i) The defect inspection apparatus (defect inspection system) 100 according to this embodiment comprises an illumination detection unit 20 having an illumination light source 22 for irradiating light (laser light) onto the sample 1 and a detection circuit (detector) 28 for detecting the inspection light from the sample 1; a stage device (stage mechanism) 10 for holding the sample 1 and having a rectilinear stage 13 and a rotational stage 12, a displacement sensor (position sensor) 60 for measuring the positions of the rectilinear stage 13 and the rotational stage 12, and an acceleration sensor (accelerometer) 70 for measuring vibrations of the rectilinear stage 13 and the rotational stage 12; and a defect detection processing system (control unit) 40 for determining defect coordinates indicating the position of a defect on the sample 1 based on the measurement values ​​from the displacement sensor 60. The defect detection processing system 40 then compares an output reference model (see FIG. 11B ) of the acceleration sensor 70, calculated in advance in accordance with an inspection mode (inspection conditions) that defines the inspection method for the sample 1, with values ​​actually measured by the acceleration sensor 70 during inspection of the sample 1 in accordance with the inspection mode, to determine the amount of mechanical positional deviation in the stage device 10, and corrects the defect coordinates using the amount of mechanical positional deviation. Here, the output reference model is a characteristic that indicates the output value of the acceleration sensor 70 when there is no mechanical vibration of the linear stage 13 and the rotation stage 12 (see FIG. 11B ). In this way, the defect inspection device 100, which can select and perform inspection in multiple inspection modes, can appropriately correct deviations in the positions (defect coordinates) of detected defects in any of the inspection modes, thereby enabling defect inspection with high coordinate accuracy.

[0074] The inspection mode includes at least one of a CAV inspection mode, which is an inspection method in which the rotation speed of the rotary stage is constant, a CLV inspection mode, which is an inspection method in which the scanning speed of light (illumination light) is constant, and an acceleration / deceleration inspection mode, which performs inspection even during acceleration and deceleration of the linear stage 13. The inspection mode may be configured to be selectable by the operator as appropriate, or may be configured to be set in advance. When an inspection mode is set, the defect detection processing system 40 corrects the defect coordinates based on the output reference model corresponding to the set inspection mode.

[0075] (ii) In this embodiment, the defect inspection system 100 corrects positional deviations due to optical vibrations in addition to positional deviations due to mechanical vibrations. Specifically, the illumination detection unit 20 includes a light beam position sensor (optical position sensor) 50 that detects the optical displacement of light from the illumination light source 22 from its reference position. The defect detection processing system 40 then corrects the optical positional deviation included in the defect coordinates based on the optical displacement detected by the light beam position sensor 50. Misalignment of the illumination position occurs regardless of the illumination light source used. In conventional defect inspection, such misalignment of the illumination light did not significantly affect defect position detection. However, as defect sizes become smaller as patterns formed on samples (wafers) become finer, even slight misalignment can make defect position identification difficult. Therefore, this embodiment corrects positional deviations due to optical vibrations (fluctuations of the illumination light) in addition to positional deviations due to mechanical vibrations, enabling highly accurate defect position identification. The light beam position sensor 50 is installed on an extension of a portion of the optical path from the illumination light source 22 to the sample 1. However, the installation position of the light beam position sensor 50 does not coincide with the light irradiation position on the sample 1. Therefore, a difference occurs between the deviation of the illumination light from the reference position (ideal optical axis) detected by the light beam position sensor 50 and the positional deviation on the sample 1. Therefore, the relationship between the amount of optical displacement detected by the light beam position sensor 50 and the amount of deviation of the light irradiation position on the sample 1 is stored in advance in a storage device. Then, the defect detection processing system 40 obtains from the storage device the amount of deviation of the light irradiation position corresponding to the amount of optical displacement actually detected by the light beam position sensor 50, and adds the amount of deviation of the light irradiation position to the defect coordinates, thereby correcting the amount of optical deviation. In this way, it is possible to accurately correct the positional deviation due to optical vibration.

[0076] (iii) As shown in FIG. 6 , the defect inspection system 100 according to this embodiment includes a means for correcting positional deviations due to optical vibrations through signal processing and a means for correcting positional deviations due to mechanical vibrations through signal processing. Specifically, the defect detection processing system 40 corrects, at the defect coordinates, positional deviations due to optical vibrations of the illumination optical system and positional deviations due to mechanical vibrations of the stage mechanism using the optical displacement amount detected by the light beam position sensor 50 and measurements by the displacement sensor (position sensor) 60 and the acceleration sensor (accelerometer) 70. This positional deviation correction is a process different from the mechanism for preventing positional deviations using the vibration isolation mounts 14 to reduce disturbance vibrations from outside the defect inspection system 100 and disturbance vibrations inside the defect inspection system 100. The positional deviations due to mechanical vibrations in the stage device 10 according to this embodiment include positional deviations caused by vibrations that have a lower frequency than the disturbance vibrations and are not removed by the vibration isolation mounts 14. The positional deviation correction according to this embodiment is not a mechanism that physically prevents positional deviation, as in the case of positional deviation removal using the vibration isolation mount 14 (the vibration isolation mount 14 structurally attenuates disturbance vibrations), but rather a process that detects the amount of optical positional deviation (vector value) and the amount of mechanical positional deviation (vector value) as signals and corrects these positional deviation amounts by digital signal processing (by adding the vector value corresponding to the positional deviation to the defect coordinates). In this way, signal processing can efficiently correct positional deviation due to low-frequency vibration, and highly accurate defect position information can be output.

[0077] In this embodiment, the defect detection processing system 40 also corrects, by signal processing, the amount of positional deviation caused by high-frequency vibrations resulting from the rotation of the rotary stage as the amount of positional deviation due to mechanical vibrations, thereby making it possible to accurately remove the effects of minute vibrations that cannot be removed by the vibration isolation mount 14.

[0078] (iv) The functions of the present embodiment can also be realized by software program code. In this case, a storage medium on which the program code is recorded is provided to a system or device, and the computer (or CPU or MPU) of the system or device reads the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-mentioned embodiment, and the program code itself and the storage medium on which it is stored constitute the present disclosure. Examples of storage media for providing such program code include flexible disks, CD-ROMs, DVD-ROMs, hard disks, optical disks, magneto-optical disks, CD-Rs, magnetic tape, non-volatile memory cards, and ROMs.

[0079] Furthermore, an operating system (OS) running on a computer may perform some or all of the actual processing based on instructions in the program code, and the functions of the above-described embodiments may be realized by this processing.Furthermore, after the program code is read from a storage medium and written to memory on the computer, a CPU of the computer may perform some or all of the actual processing based on instructions in the program code, and the functions of the above-described embodiments may be realized by this processing.

[0080] Furthermore, the program code of the software that realizes the functions of the embodiment may be distributed via a network and stored in a storage means such as a hard disk or memory of the system or device, or in a storage medium such as a CD-RW or CD-R, so that when used, the computer (or CPU or MPU) of the system or device reads and executes the program code stored in the storage means or storage medium.

[0081] The technology of the present disclosure is not limited to the configuration example of this embodiment and includes various modifications. This embodiment is provided to clearly explain the technology of the present disclosure. Therefore, the technology of the present disclosure is not necessarily limited to a configuration including all of the described configurations. Furthermore, the processes and techniques described in this embodiment are not inherently related to any specific device and can be implemented by combining each component. Furthermore, various types of general-purpose devices can also be added. A dedicated device may be constructed to perform the functions of this embodiment. Furthermore, various functions can be formed by appropriately combining multiple components disclosed in this embodiment. For example, some components may be omitted from all of the components shown in the embodiment, or different components may be appropriately combined.

[0082] Although specific embodiments are described in this disclosure, they are in all respects for the purpose of explanation (understanding the technology of the present disclosure) and not for the purpose of limitation. Those skilled in the art will recognize that there are many combinations of hardware, software, and firmware suitable for implementing the technology of the present disclosure. For example, the software described can be implemented in a wide variety of programming or scripting languages, such as assembler, C / C++, Perl, Shell, PHP, Java (registered trademark), etc.

[0083] Furthermore, in the above-described embodiment, the control lines and information lines are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. All components may be interconnected.

[0084] In addition, other implementations of the present disclosure will be apparent to those skilled in the art from consideration of the present embodiments. The specification and examples are exemplary only, with the scope and spirit of the technology of the present disclosure being indicated by the following claims.

[0085] REFERENCE SIGNS LIST 1 sample 10 stage device 11 sample stage 12 rotation stage 13 linear stage 14 vibration isolation mount 20 illumination detection unit 21 illumination optical system 22 illumination light source 23 optical element 25 detection optical system 26 condensing optical element (condensing lens) 40 defect detection processing system 100 defect inspection device N rotation speed O center of sample P1 sample transfer position P2 scanning start position P3 sample periphery scanning position G gap between sample stage and illumination detection unit

Claims

1. A defect inspection system for inspecting defects in a sample, comprising: an illumination and detection unit having a light source that irradiates light onto the sample and a detector that detects light from the sample; a stage mechanism that holds the sample and has a linear stage and a rotational stage, a position sensor that measures the positions of the linear stage and the rotational stage, and an accelerometer for measuring vibrations of the linear stage and the rotational stage; and a control unit that determines defect coordinates that indicate the position of the defect based on measurements by the position sensor, wherein the control unit determines an amount of mechanical positional deviation in the stage mechanism by comparing an output reference model of the accelerometer calculated in advance in accordance with an inspection mode that specifies a method for inspecting the sample with a value actually measured by the accelerometer during inspection of the sample in accordance with the inspection mode, and corrects the defect coordinates using the amount of mechanical positional deviation.

2. A defect inspection system according to claim 1, wherein the output reference model represents an output value of the accelerometer in the absence of mechanical vibration of the linear stage and the rotary stage.

3. A defect inspection system according to claim 1, wherein the inspection mode includes at least one of a CAV inspection mode, which is an inspection method in which the rotation speed of the rotating stage is constant, a CLV inspection mode, which is an inspection method in which the scanning speed of the light is constant, and an acceleration / deceleration inspection mode in which inspection is performed even while the linear stage is accelerating and decelerating, and the control unit corrects the defect coordinates based on the output reference model corresponding to the inspection mode selected by an operator or a preset inspection mode.

4. A defect inspection system as described in claim 1, wherein the illumination detection unit includes an optical position sensor that detects the amount of optical displacement from a reference position for irradiation with light from the light source, and the control unit corrects the amount of optical positional deviation contained in the defect coordinates based on the amount of optical displacement.

5. A defect inspection system as described in claim 4, wherein the control unit acquires the amount of deviation in the light irradiation position corresponding to the amount of optical displacement actually detected by the light position sensor from a memory device that stores the relationship between the amount of optical displacement and the amount of deviation in the light irradiation position on the sample, and corrects the amount of optical deviation by adding the amount of deviation in the light irradiation position to the defect coordinates.

6. A defect inspection system for inspecting defects in a sample, comprising: an illumination detection unit having a light source that irradiates light onto the sample, a detector that detects light from the sample, and an optical position sensor that detects an amount of optical displacement from a reference position for irradiation with light from the light source; a stage mechanism that holds the sample and has a linear stage and a rotation stage, a position sensor that measures the positions of the linear stage and the rotation stage, and an accelerometer that measures vibrations of the linear stage and the rotation stage; and a control unit that determines defect coordinates that indicate the position of the defect based on measurements by the position sensor, wherein the control unit uses the amount of optical displacement detected by the optical position sensor and the measurements by the position sensor and the accelerometer to correct an amount of positional deviation due to optical vibration of the illumination detection unit and an amount of positional deviation due to mechanical vibration of the stage mechanism in the defect coordinates.

7. A defect inspection system according to claim 6, wherein the amount of positional deviation due to optical vibration and the amount of positional deviation due to mechanical vibration are vector values, and the control unit corrects the positional deviation of the defect coordinates by reflecting the vector values ​​on the defect coordinates.

8. A defect inspection system as described in claim 6, wherein the stage mechanism further has a vibration isolation mount for reducing disturbance vibrations from outside the defect inspection system and disturbance vibrations inside the defect inspection system, and the positional deviation amount due to the mechanical vibrations includes a first type of positional deviation amount due to vibrations that have a lower frequency than the disturbance vibrations and are not removed by the vibration isolation mount.

9. A defect inspection system as claimed in claim 8, wherein the positional deviation amount due to mechanical vibration further includes a second type of positional deviation amount due to vibration of a higher frequency than the first type of positional deviation amount, which is caused by the rotational operation of the rotating stage.

10. A defect inspection system as claimed in claim 9, wherein the vibration isolation mount structurally damps the disturbance vibration, and the control unit performs positional deviation correction of the defect coordinates as data processing by adding the first type positional deviation amount and the second type positional deviation amount caused by the mechanical vibration as vector values ​​to the value of the defect coordinates.

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