JP2002257753A - Inspection methid and inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect attached foreign matter on the surface of a transparent or translucent sample in a visible light wavelength region without including inner foreign matter on the inside of the sample. SOLUTION: While X-ray beams L irradiate the inspection surface of a visible light transmissible sample B at a smaller angle than a critical angle to the inspection surface, the sample B and the X-ray beams L are relatively moved. The foreign matter A attached on the inspection surface of the sample B is detected based on the intensity variation of the X-ray beams L' reflected on the inspection surface of the sample B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection technique suitable for detecting a transparent or translucent foreign substance in a visible light wavelength region.

[0002]

2. Description of the Related Art Inspection of a foreign substance adhering to a glass substrate or the like is often performed using a foreign substance inspection apparatus utilizing laser light. This foreign matter inspection apparatus irradiates a sample with laser light and detects scattered light or reflected light to detect foreign matter adhering to the sample surface with a resolution of about 100 μm.
Although foreign matter adhering to the sample surface can be observed by the stylus method or other methods, this foreign matter inspection apparatus can inspect the sample surface at a higher speed as compared with other methods.

[0003]

However, an optically transparent glass substrate has a refractive index of light of more than 1;
Transmits laser light. Therefore, according to the above-described conventional foreign matter inspection apparatus, the foreign matter contained in the glass substrate is also detected without distinction from the foreign matter attached to the glass substrate surface. That is, it is difficult to determine whether the detected foreign matter is attached to the surface of the glass substrate or contained within the glass substrate. This can be said not only for the foreign substance inspection of the glass substrate but also for the whole foreign substance inspection of the transparent or translucent body in the visible wavelength region.

Accordingly, an object of the present invention is to provide an inspection apparatus capable of detecting a foreign substance on the surface of a transparent or translucent sample in a visible light wavelength range without the presence of foreign substances inside the sample.

[0005]

In order to solve the above-mentioned problems, in the present invention, an X-ray is irradiated on an inspection surface of a sample through which visible light passes so as to form an angle smaller than the critical angle with the inspection surface. By detecting a change in the intensity of the X-rays reflected from the inspection surface, a foreign substance that has come into contact with the inspection surface of the sample that transmits visible light is detected.

In the following, an embodiment of the present invention will be described in detail, but the matters included in the specific configuration described therein have the maximum possible degree of freedom of combination.
All of the combinations constitute the invention. For example, in the following, an embodiment in which a part of the configuration described as an embodiment of the present invention is appropriately deleted is also included as one of the embodiments of the present invention.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, referring to FIGS. 1 and 2, the principle of detecting foreign matter according to the present embodiment will be described.

A sample B, which is a transparent or translucent body in the visible light wavelength region, is placed in an atmosphere having a higher refractive index than the material, and an X-ray beam L having a beam diameter W is applied to the surface of the sample B ( Irradiation is performed on the inspection surface at an incident angle ω smaller than the critical angle (the angle formed between the inspection surface and the incident direction of the X-ray beam L).
When the X-ray beam L is incident on a local region on the surface of the sample B, it undergoes almost total reflection in the local region, and the surface layer of the sample B
(About several nm in depth). Here, the critical angle is an angle between the inspection surface and the incident X-ray when the intensity of the reflected X-ray is 50% of the intensity of the incident X-ray.

[0010] Here, as shown in FIG. 1A, the irradiation area b of the X-ray beam L has a diameter r (≦≦) smaller than the beam diameter W.
W), the foreign matter A (hereinafter, referred to as an attached foreign matter) adheres, and the attached foreign matter A causes a part L _{2 of the} X-ray beam L.
Is blocked before reaching the surface of the sample B. Further, X-ray beam incident on the surface of Sample B also part L _3, sample B
After being reflected by the surface of
Only the balance L ₁ is, after reflected by the surface of the sample B, and travels in the raw direction. Therefore, the intensity of the reflected beam fluctuates due to the presence of the attached foreign matter A.

On the other hand, even if the sample B contains foreign matter A ′ (hereinafter referred to as “encapsulated foreign matter”), the X-ray beam L does not reach the included foreign matter A ′. , The intensity of the reflected beam does not vary.

Therefore, if the reflected beam is detected by the X-ray detector while scanning the surface of the sample B with the X-ray beam L having the beam diameter W, the foreign matter A adhering to the sample B can be removed. 'And can be detected without being mixed. That is, since the intensity of the reflected beam fluctuates due to the presence of the adhered foreign matter A regardless of the presence of the included foreign matter A ′, the adhered foreign matter A of the sample B is removed by monitoring the intensity of the reflected beam. It can be detected without mixing with the inclusion foreign matter A '. Specifically, as shown in FIG. 1B, the intensity I of the reflected beam in the region b where the adhered foreign matter A exists is
Smaller than the intensity Ir of the reflected beam at the other clean area, and, to indicate a value greater than 0, by detecting the detection value is smaller position of the X-ray detector than the appropriate threshold I _1, The position of the attached foreign matter on the surface of the sample B can be detected with a resolution determined according to the beam diameter W of the X-ray beam L.

The intensity I of the reflected beam in the area b where the foreign matter A is attached is determined by the beam diameter W of the incident beam L, the diameter r of the foreign matter A, and the intensity Ir of the reflected beam in other areas.
Has a relationship approximately expressed by the following equation (1).

I = Ir × (W ² −r ² ) (1)

For this reason, by substituting the detection values I and Ir of the X-ray detector and the beam diameter W of the incident beam L into the equation (1), the size of the foreign matter A adhering to the sample surface is calculated. be able to.

On the other hand, as shown in FIG. 2A, if the foreign matter A on the surface of the sample B has a diameter r larger than the beam diameter W of the X-ray beam L (r> W), X Depending on the irradiation position of the line beam L, the X-ray beam L is completely blocked by the attached foreign matter A before reaching the surface of the sample B. When the incident optical path of the X-ray beam L is shifted to the left in FIG. 2A by an appropriate distance, the X-ray beam L is partly reflected on the surface of the sample B and then blocked by the adhered foreign matter A. , The rest being sample B
Before it reaches the surface of the
After all, it does not travel in the direction of total internal reflection.

Therefore, when the reflected beam is detected by the X-ray detector while scanning the surface of the sample B with the X-ray beam L having the beam diameter W, as shown in FIG. The intensity I of the reflected beam when the incident optical path has a predetermined positional relationship with the attached foreign matter A is substantially zero. For this reason, an appropriate threshold value I ₂ is provided, and a position where the detection value of the X-ray detector is smaller than the threshold value I ₂ is detected as a position where the intensity of the reflected beam is almost zero, thereby obtaining the sample B. Can be detected with a resolution determined according to the beam diameter W of the X-ray beam L.

In this case, the width (Δd in FIG. 2B) of the region where the detection value of the X-ray detector is almost 0 is the beam diameter W and the incident angle ω of the incident beam L, and the foreign matter A Has a relationship represented by the following equation (2).

Δd = 2r / tan (ω) −W / tan (ω) (2)

Therefore, the scanning distance Δd during which the detection value of the X-ray detector is almost 0, the beam diameter W of the incident beam L, and the incident angle ω are substituted into the equation (2). Accordingly, the size of the foreign matter A attached to the sample surface can be calculated.

As described above, the surface of the sample B is irradiated with the X-ray beam L at an incident angle ω smaller than the critical angle, and the intensity of the reflected beam is changed to the intensity Ir of the reflected beam on the clean surface of the sample B. Smaller thresholds I ₁ and I ₂ (threshold I ₁ for detecting adhering foreign matter having a diameter smaller than the beam diameter W of the incident beam L, and removing adhering foreign matter having a diameter larger than the beam diameter W of the incident beam L). Compared with the threshold value I ₂ ) for detection, the result of the comparison indicates that the adhering foreign matter having a diameter smaller than the beam diameter W of the incident beam L and the beam diameter W of the incident beam L
It can be seen that it is possible to detect an attached foreign matter having a larger diameter than that.

Further, in the state shown in FIGS. 1A and 2A, a scattered light detector is disposed so as to face the surface of the sample B, and the surface of the sample B is irradiated with laser light from the front. For example, the scattered light detector detects scattered light from both the attached foreign matter A of the sample B and the included foreign matter A ′ of the sample B.
That is, the foreign matter A adhering to the sample B is detected by the scattered light detector.
And the foreign substance A 'included in the sample B are detected without distinction. As described above, the foreign matter A attached to the sample B can be detected by the X-ray detector without mixing with the foreign matter A 'included in the sample B. Therefore, the detection result by the X-ray detector and the scattered light detection The inclusion A ′ of the sample B can be extracted by taking the difference from the detection result by the detector.

Next, referring to FIG. 3 and FIG. 4, the configuration of the inspection system for detecting a foreign substance of a transparent or translucent body in the visible light wavelength region based on such a detection principle will be described.
An example in which a sample B is irradiated with a monochromatic X-ray beam on CuKα1 (λ = 1.5406 °) will be described.
FIGS. 3 and 4 show the following for convenience of description.
An orthogonal coordinate system xyz having a horizontal plane as an xy plane is defined.

The inspection system according to this embodiment is similar to that shown in FIG.
As shown in FIG. 2, an X-ray beam irradiation system 10 for emitting an X-ray beam L having an appropriate beam diameter (here, for example, about 10 μm), a sample table 30 on which a sample B is placed, and a surface of the sample B An X-ray beam detection system 20 for detecting the X-ray beam L ′ reflected by the light source, a moving mechanism 40 for changing the relative positional relationship between the sample stage 30, the X-ray beam irradiation system 10, and the X-ray beam detection system 20, It has a base (not shown) to which the mechanism 40 and the like are fixed, a control device 50 for controlling the entire system, and the like.

An X-ray beam irradiation system 10 appropriately generates an X-ray source (for example, an X-ray generator such as a rotating cathode of Cu) 11 for generating an X-ray beam L, and an X-ray beam L from the X-ray source 11. A first slit 12 that passes through a small beam diameter (for example, about 0.5 mm), a crystal spectroscope 13 made of Si (111) that selects the wavelength of the X-ray beam L emitted from the first slit 12, and a monochromatic The second slit 14 that allows the converted X-ray beam L to pass through an appropriate beam diameter (for example, about 0.1 mm), collects the X-ray beam L from the second slit 14, and converts the X-ray beam substantially parallel to the x direction. It is configured by a 10: 1 X-ray reflecting concave mirror 15 that reflects as a line beam. With such a configuration, the X-ray beam irradiation system 10
Then, a monochromatic X-ray beam L for irradiating the sample B having a beam diameter of about 10 μm and an opening angle of about ± 1 mrad (0.06 °) at the focal position is emitted in a direction substantially parallel to the x direction.

The X-ray beam detection system 20 outputs an X-ray beam L '
Light-receiving slit 21 through which light passes, X-ray beam L ′ passing through light-receiving slit 21 or light-receiving slit 2
An X-ray detector 22 for detecting the intensity of the X-ray beam L 'that has arrived without passing through the X-ray detector 1, an orthogonal biaxial stage 23 for adjusting the position of the light receiving slit 21 with respect to the light receiving surface of the X-ray detector 22, It consists of. Orthogonal 2-axis stage 2
Reference numeral 3 includes a first table movable in a direction approaching the X-ray detector 22 and the opposite direction, and a second table movable reciprocally in the y direction on the first table. With such a configuration, when the X-ray beam L is reflected on the surface of the sample B, the reflected beam L ′ passes through the light-receiving slit 21 after the position adjustment (if there is no light-receiving slit 21, the light-receiving slit 21 (Directly without intervention), and is detected by the X-ray detector 22.

For example, when the X-ray beam irradiation system 10 is immovably fixed to the base, the moving mechanism 40 includes a detection system moving unit for moving the X-ray beam detection system 20 and a sample stage. It is composed of three parts: a sample stage moving unit for moving 30, and a driving unit that transmits a driving force of a motor to the detection system moving unit and the sample stage moving unit. The detection system moving unit includes a column 41 on which a circular guide surface 41a having a central axis set in the y direction passing through the focal point of the X-ray beam L from the X-ray beam irradiation system 10 and the X-ray beam detection system 20 are arranged. while holding has a moving base 42, which slides about the y-axis (theta ₁ direction) on a circular guide surface 41a. According to such a detection system moving unit, the position and orientation of the light receiving surface of the X-ray beam detection system 20 with respect to the X-ray beam irradiation system 10 can be changed by driving the moving table 42 with the motor of the driving unit. . Also, sample stage moving portion slides bed 43 concentric arcuate guide surface 43a of the circular guide surface 41a is formed of the column 41, the upper arcuate guide surface 43a about the y-axis (theta ₂ direction) movement Table 44, an orthogonal three-axis stage 45 placed on the moving table 44 (a first reciprocating table 45a that moves on the moving table 44 in a direction perpendicular to the arc-shaped guide surface 43a, and a y-direction that moves on the first reciprocating table 45a Second reciprocating table 45b, arc-shaped guide surface 43a on second reciprocating table 45b
A third reciprocating table 45c) that moves in a tangential direction of a rotary table that rotates in the φ direction on a plane including the moving direction of the first reciprocating table 45a and the moving direction of the second reciprocating table 45b on the orthogonal three-axis stage 45. 46, rotary table 46
Let inclined two directions (Kaix direction and χy direction) the sample stage 30 surface moves the sample stage 30 in the rotation plane (the plane of the sample is placed) to the Kaix direction (swing Kaishita _two directions) And a two-axis swivel stage 47. According to such a sample stage moving unit, the swivel stage 47,
By driving the rotary table 46, the orthogonal three-axis stage 45, and the moving table 44 with the motor of the driving unit, the position and orientation of the inspection surface of the sample B with respect to the X-ray beam irradiation system 10 can be changed.

The control unit 50 controls the motor of the drive unit of the moving mechanism 40 so that the inspection surface of the sample B is scanned by the X-ray beam L incident at an incident angle ω smaller than the critical angle, The output signal of the X-ray detector 22 of the line beam detection system 20 is sequentially received, and based on the output signal, the foreign matter A on the sample B is detected.

According to such a system configuration, the X-ray beam L is incident on the sample B at an incident angle ω smaller than the critical angle in the inspection of the sample B in accordance with the above-described detection principle, so that the foreign matter adhering to the sample B is removed. , Can be detected without being mixed with the foreign matter included in the sample B. Further, when it is necessary to encapsulated foreign substances of the sample B is also possible to detect, as shown in FIG. 4, the mobile base that slides round guide surface 41a of the column 41 in the theta ₁ direction by control of the controller 50 ( (Not shown), and a foreign matter inspection device 6 using a laser
0 may be attached. The foreign matter inspection device 60 includes a laser oscillator 61 for irradiating a laser beam M, a laser oscillator 6
The laser beam M from 1 has an appropriate diameter (for example, about 10 μm)
And a scattered light detector 63 that detects the scattered light M ′ on a light receiving surface substantially perpendicular to the optical path of the laser light M from the light collecting optical system 62. Then, the control device 50 in this case, in addition to the output signal of the X-ray detector 22,
The output signal of the scattered light detector 63 is also sequentially received.
Based on the difference between the types of output signals, the foreign substance A ′ contained in the sample B
Need to be detected.

It is to be noted that the system configuration described here is an example of the configuration, and unless the system configuration is as described above, it does not mean that an inspection system for detecting a foreign substance based on the above-described detection principle cannot be realized. For example, X-ray beam detection system 2
0 may be any configuration as long as the intensity of the X-ray beam from the surface of the sample B can be detected,
The X-ray beam irradiation system 10 may have any configuration as long as it can emit an appropriate X-ray beam (not limited to a monochromatic X-ray beam having a beam diameter of 10 μm). The moving mechanism 40 includes the sample stage 30 and the X-ray beam irradiation system 1.
If the relative positional relationship between the X-ray beam detection system 20 and the X-ray beam detection system 20 can be changed, it is not always necessary to be configured as shown here.
0, the X-ray beam irradiation system 10 and the sample stage 30 may be moved respectively.

Next, a method for detecting foreign matter by the inspection system will be described. Here, a case where a 25-inch disk-shaped glass substrate is used as the sample B will be described as an example.

Prior to the start of the foreign substance detection of the sample B, it is necessary to make the χy axis and the χx axis of the swivel stage 47 substantially parallel to the y direction and the x direction, respectively, and then execute the following adjustment processing. There is. Note that the rotation angle Δθ ₂ of the moving base 44 during the adjustment process is different from the moving base 44 at this time.
Is represented by an angular displacement with respect to the position of.

A slit having a hole diameter of 1.0 mm is attached as the light receiving slit 21 and X-ray beam irradiation from the X-ray beam irradiation system 10 is started. Then, while sliding the moving base 42 in the theta ₁ direction, the intensity of the X-ray beam L passing through the receiving slit 21 sequentially detected by the X-ray detector 22, the detected value of the peak (hereinafter, the peak value, The movable table 42 is stopped at a position indicating the initial intensity of the X-ray beam L). This stop position is set as a reference position of the moving table 42. The rotation angle Δθ ₁ of the moving table 42 hereinafter is represented by an angular displacement from the reference position.

Next, the sample B is fixed on the surface of the sample stage 30, and the X-ray beam irradiation from the X-ray beam irradiation system 10 is restarted. Thereafter, while moving the sample stage 30 in the z direction, the intensity of the X-ray beam L passing through the light receiving slit 21 is sequentially detected by the X-ray detector 22, and the detected value is approximately equal to the initial intensity of the X-ray beam L. The sample stage 30 is stopped at the position where the ratio becomes 50%. Further, while sliding the movable carriage 44 in the theta ₂ direction, X-rays beam L passing through the light-receiving slit 21
Are sequentially detected by the X-ray detector 22, and the movable table 44 is stopped at a position where the detected value shows a peak. By repeating this process (movement of the sample stage 30 in the z-direction, the sliding of the moving base 44 in the theta ₂ direction), and finally, the peak of the detected intensity by X-ray detector 22, the X-ray beam The rotation angle of the movable base 44 when the initial strength of L becomes about 50% is detected. The rotating table 46 being adjusted
Is based on the rotary table 46 at this time.
(Δφ = 0 °).

Thereafter, the rotary table 46 is set to Δφ = 180
Position from the rotated until the °, repeats the more similar process (movement of the sample stage 30 in the z-direction, the sliding of the moving base 44 in the theta ₂ direction). Thereby, the rotary table 4
6, even when the rotation angle Δφ is 180 °, the rotation angle of the movable base 44 when the peak of the detection intensity of the X-ray detector 22 becomes about 50% of the initial intensity of the X-ray beam L is detected.

Then, an average value of the rotation angles detected before and after the rotation of the turntable 46 is calculated, and the movable table 44 is moved to the position of the rotation angle indicated by the average value. After that, the rotary table 46 is rotated to the position of Δφ = 90 °, and then the X-ray beam irradiation from the X-ray beam irradiation system 10 is restarted. Then, while moving the sample stage 30 in the z direction, the intensity of the X-ray beam L passing through the light receiving slit 21 is sequentially detected by the X-ray detector 22, and the detected value is approximately equal to the initial intensity of the X-ray beam L. The sample stage 30 is stopped at the position where the ratio becomes 50%. Further, while the sample stage 30 is swung by the swivel stage 47, the intensity of the X-ray beam L passing through the light receiving slit 21 is sequentially detected by the X-ray detector 22,
The sample stage 30 is stopped at a position where the detected value shows a peak. Such processing (movement of the sample stage 30 in the z direction,
By repeating the swing of the sample stage 30, the inclination angle of the sample stage 30 when the peak of the detection intensity by the X-ray detector 22 becomes about 50% of the initial intensity of the X-ray beam L finally ( The rotation angle Δχθ ₂ ) of the swivel stage 47 from the initial position is detected.

Thereafter, the rotary table 46 is set to Δφ = −90.
After rotating to the position of °, the same processing (movement of the sample stage 30 in the z direction, swinging of the sample stage 30) is repeated. Thereby, the rotation angle Δφ of the turntable 46
Is −90 °, the inclination angle of the sample stage 30 when the peak of the detection intensity by the X-ray detector 22 becomes about 50% of the initial intensity of the X-ray beam L is detected.

The rotation angle Δφ of the rotary table 46
Is calculated at ± 90 °, the average of the detected tilt angles is calculated, and the sample table 30 is tilted with respect to the Δx axis of the swivel stage 47 by the tilt angle indicated by the average value.

By the above adjustment processing, the posture of the sample B is adjusted so that the inspection surface of the sample B is substantially parallel to the X-ray beam L from the X-ray beam irradiation system 10. The above adjustment process may be performed manually by an operator, or may be automated under the control of the control device 50.

When the adjustment process is completed as described above, the following foreign substance detection process is executed under the control of the control device 50. During the following foreign substance detection processing,
Unlike during the adjustment process described above, the position of each part of the moving mechanism 40 is represented by a displacement amount based on the position immediately after the adjustment process. For example, the rotation angle Δφ of the rotary table 46 during the inspection processing is represented by a rotation angle based on the position of the rotary table 46 immediately after the adjustment processing.

First, the light receiving slit 21 is removed so that the X-ray detector 22 can also detect the X-ray beam L ′ reflected on the inspection surface having the long swell of the cycle. Thereafter, the X-ray beam L from the X-ray beam irradiation system 10, so as to enter the inspection surface of the sample B at ω smaller incident angle than the critical angle, is slid the moving base 44 in the theta ₂ direction. The critical angle of X-rays varies depending on the wavelength. However, X-rays having a wavelength of 0.15 ° or more are generally smaller than the critical angle if they are incident on the inspection surface of the sample B at an incident angle ω of about 0.15 °. This means that light was incident at a small incident angle. Therefore, here, the moving table 44 is rotated by the rotation angle Δθ ₁ = 0.15 ° ± 10 ^-4 ° so that the incident angle ω of the X-ray beam L is 0.15 ° ± 10 ^-4 °. . Then, the moving table 42 is rotated by the rotation angle Δθ ₂ = 2ω so that the X-ray beam L ′ reflected on the inspection surface of the sample B is detected by the X-ray beam detection system 20.

In such a state, as shown in FIG. 5 (a), while rotating the sample B by rotating the turntable 46, the swivel stage 47 is driven every time the sample B completes one rotation. The sample B is moved by a predetermined distance in the Δy direction. Accordingly, the scanning trajectory of the X-ray beam L on the inspection surface of the sample B becomes a concentric circle surrounding the rotation center of the turntable 46. The irradiation area T of the X-ray beam L having a beam diameter of 10 μm has a width in the φ direction (circumferential width of the scanning locus) of about 3.8 mm, and a width in the y direction (radial direction of the scanning locus) of about 0.01 mm. The resolution in the φ direction (circumferential direction) and the resolution in the Δy direction (radial direction)
About 7.6 ° (at a position 30 mm from the center of rotation) and about 0.0
1 mm. For this reason, the foreign matter A
Is present, as shown in FIG. 5 (b), a band-shaped region T ′ corresponding to the resolution in the φ direction and the resolution in the χy direction is formed by the threshold processing of the output of the X-ray It is detected as the position where A exists. In FIG. 5B, the band-shaped region T ′ where the intensity I of the reflected X-ray is almost 0 is shown.
(Reflected X-ray intensity I is, and FIG. 2 (b) threshold I ₂ was less area than the) indicates a thin line, the reflected X-ray band region T intensity I is smaller than the large cleaning area than zero ' (reflected X-ray intensity I is greater than the threshold I ₂ of FIG. 2 (b), FIG. 1
The smaller was the area than the threshold I ₁ of the (b)) is indicated by a thick line.

When the sample B moves in the Δy direction by the radius of the sample B by the above scanning, the sample B is rotated by a predetermined angle by rotating the turntable 46 as shown in FIG. While rotating the sample B by a predetermined angle, the swivel stage 47 drives the sample B to reciprocate in the Δx direction so as to pass through the rotation center of the rotary table 46. Accordingly, the scanning trajectory of the X-ray beam L on the inspection surface of the sample B becomes a plurality of straight lines radiating from the rotation center of the turntable 46.
The irradiation area T of the X-ray beam L having a beam diameter of 10 μm has a width in the φ direction of about 3.8 mm and a width in the χx direction of about 0.01 mm. In this case, the resolution in the φ direction and the resolution in the χx direction are about 0.1 mm. 02 ° (30mm from center of rotation)
And about 3.8 mm. For this reason, if the foreign matter A is present on the inspection surface of the sample B, as shown in FIG. 6B, the resolution in the φ direction and the resolution in the χx direction are determined by threshold processing of the output of the X-ray detector 22. Is detected as an existing position of the attached foreign matter A. Incidentally, in FIG. 6 (b), the intensity I of the intensity I is approximately 0 at a band-like region T '' (the reflection X-rays of the reflected X-rays was smaller than the threshold I ₂ shown in FIG. 2 (b) region ) Is shown by a thin line, and the band-shaped region T ″ in which the intensity I of the reflected X-ray is larger than 0 and smaller than the clean region (the intensity I of the reflected X-ray is larger than the threshold I _{2 in} FIG. 1 smaller was region than the threshold I ₁ of the (b))
Is indicated by a thick line.

The control device 50 overlaps the strip-shaped regions T ′ and T ′ (FIGS. 5B and 6B) detected as a result of scanning the inspection surface of the sample B by the above two types of scanning methods. Calculate the area. As a result, as shown in FIG. 7, the area where the adhered foreign matter A is present is defined as a rectangular area P of 0.01 mm × 0.01 mm (that is, with a resolution of about the beam diameter of the X-ray beam L).
Can be detected.

As described above, according to the method according to the present embodiment, the adhered foreign matter A of the sample B is removed by the above-described detection principle.
The sample B can be detected without being mixed with the inclusion foreign matter A ′.

When it is necessary to further detect the foreign substance A 'included in the sample B, the following processing is further executed by the control of the control device 50 during the scanning by the X-ray beam L described above.

The movable table to which the foreign substance inspection device 60 is fixed is θ
_By sliding in _one direction, the light receiving surface of the scattered light detector 63 is positioned in front of the inspection surface of the sample B. Thereafter, the inspection surface of the sample B is irradiated with the laser light M by oscillating the laser oscillator 61. In this state, if the scanning by the X-ray beam L is started, the inspection surface of the sample B is also scanned by the laser light M. During this time, the control device 50 further monitors the intensity of the scattered light M ′ detected by the scattered light detector 63, and detects an area where the intensity of the scattered light is equal to or more than a predetermined value as a foreign substance existing area. . FIG. 8 shows the detection results. The laser beam M is sample B
Is scattered not only by the extraneous substance A but also by the extraneous substance A ′ of the sample B. Therefore, in this detection result, the existence area P of the extraneous substance A and the existence area P ′ of the extraneous substance A ′ are mixed. I have. Therefore, the control device 50 detects the detection result by the scanning of the laser beam M (FIG. 8) and the detection result by the scanning of the X-ray beam L.
The difference from FIG. 7 is calculated. As shown in FIG. 9, this difference is obtained from the detection result (FIG. 8) obtained by scanning the laser beam M.
The result obtained by removing the detection result (FIG. 7) by the scanning of the line beam L is obtained, that is, only the region P ′ where the foreign substance A ′ contained in the sample B is extracted is extracted. Therefore, by using the scanning of the laser beam M and the scanning of the X-ray beam L in this way, it is possible to detect the adhered foreign substance A of the sample B without mixing with the foreign substance A ′ included in the sample B, and to detect the foreign substance A of the sample B. Inclusion foreign matter A 'can also be detected.

In the above description, the scanning trajectory of the inspection surface of the sample B is radial and concentric, but it is not always necessary to do so. For example, sample B is
全体 Scanning the entire inspection surface of the sample B by feeding a predetermined distance in the χy direction each time the oscillating is performed in the 方向 x direction, and further, sending the sample B a predetermined distance in the χx direction each time the oscillating movement of the sample B is performed in the χy direction. Thus, the entire inspection surface of the sample B may be scanned. As a result, the X-ray detector 22
By the threshold processing of the output of
It is detected as a band region in the 。x direction and a band region in the χy direction as shown in FIGS. 10A and 10B. Therefore, as in the case described above, by detecting the overlapping area of the two types of band-like areas, the presence area of the attached foreign matter A is reduced to about the beam diameter of the X-ray beam L as shown in FIG. It can be detected with resolution.

In the above description, only the area where the foreign matter is present on the sample is detected. Of course, during scanning, the control device 50 detects the size of the foreign matter using the above-described equations (1) and (2). You may make it.

In the above description, the intensity of the X-ray beam L 'reflected on the inspection surface of the sample B is detected by the X-ray detector 22, but instead of the X-ray detector 22, an X-ray electron microscope is used. (Zooming detector).

More specifically, as shown in FIG. 11, the X-ray beam detection system 20 on the movable table 42 is detachably connected to the light receiving slit 24 and the light receiving slit 2 for passing the X-ray beam L '.
X-ray beam L 'that passed through 4 (if there is no light-receiving slit, X-ray beam L' that arrived without passing through the light-receiving slit)
, And the like. The focus of the X-ray electron microscope 25 is set on the center axis of the arc-shaped guide surface 43a of the bed 43 (the rotation center axis of the moving base 44).

The X-ray beam irradiation system 10 includes an X-ray source 11 similar to that described above, and an X-ray beam L from the X-ray source 11.
A rectangular slit hole of appropriate size (for example, about 0.05 m
m × 10 mm) and a Si that emits a monochromatic X-ray beam substantially parallel to the x direction by selecting the wavelength of the X-ray beam L emitted from the first slit 12 ′ and the first slit 12 ′
(111) Crystal spectroscope 13 ', X from crystal spectroscope 13'
The line beam L is applied to a rectangular slit hole of an appropriate size (for example,
(About 0.02 mm × 10 mm). Moreover, further provided, on the moving base 73, a slit hole 0.02 mm × 10 mm used in the aforementioned adjustment process the moving base 73 which slides on a circular guide surface 41a of the column 41 about the y-axis (theta ₁ direction) The light receiving slit 72 and the X-ray detector 71 are fixed.

In such a system as well, the detection processing is executed after the adjustment processing using the X-ray detector 71 and the like is performed, as in the case described above. The detection process in this case is
For example, it is performed as follows. After a slit having a rectangular slit hole having a width of 0.02 mm is attached as the light receiving slit 24, the X-ray beam L from the X-ray beam irradiation system 10 is incident on the inspection surface of the sample B at an incident angle of 0.15 °. in, the movable carriage 44 slides in theta ₂ direction. Further, the slide of the movable table 40 positions the X-ray detection system 20 so that the scattering angle becomes 0.3 °.

In this state, the intensity of the reflected X-ray beam L ′ passing through the light receiving slit 24 is sequentially measured by the X-ray electron microscope 25. Then, while sliding the movable carriage 44 in the theta ₂ direction, the detection value of the X-ray electron microscope 25 stops the moving base 44 at a position a peak. Thereafter, the rotary table 46 is rotated to the position of [Delta] [phi = 180 °, further similar process (slide movable carriage 44 in the theta ₂ direction). It calculates an average value of the rotation angle [Delta] [theta] ₂ of the moving table 44 detected by the rotation around the rotary table 46 to move the moving table 44 to the position of the rotational angle indicated by the average value. Further, while moving the sample stage 30 in the z direction, the sample stage 30 is stopped at a position where the detection value of the X-ray electron microscope 25 shows a peak (hereinafter, referred to as a first stop position).

Thereafter, when the rotation angle Δφ of the rotary table 46 is 90 ° or −90 °,
The same processing is performed as in the case where the rotation angle Δφ is 0 ° or 180 °. Then, while moving the sample stage 30 in the z direction, X
The sample stage 30 is stopped at a position where the detection value of the line electron microscope 25 shows a peak (hereinafter, referred to as a second stop position).

Then, the same processing is repeated until the shift between the first stop position and the second stop position in the z direction is within 10 μm. After that, the inspection process is started after the light receiving slit 24 is removed so that the X-ray electron microscope 25 can also detect the X-ray beam L ′ reflected on the inspection surface where the long swell of the cycle occurs. In the inspection process, for example, while rotating the sample B by rotating the turntable 46, the sample B is moved by a predetermined distance in the Δy direction by driving the swivel stage 47 each time the sample B completes one rotation. Accordingly, the scanning trajectory of the X-ray beam L on the inspection surface of the sample B becomes a concentric circle surrounding the rotation center of the turntable 46. Here, the irradiation area of the X-ray beam L is φ
The width in the direction (circumferential width of the scanning locus) is about 3.8 mm, and the width in the χy direction (radial direction of the scanning locus) is about 10 mm. For this reason,
For 2.5 inch magnetic storage medium glass (storage area width 10 mm) with a 1 inch center hole,
Only two scans in the y direction are required. FIG. 12 shows an example of the detection result in this case.

[0057]

According to the present invention, it is possible to detect a foreign substance on the surface of a transparent or translucent sample in a visible light wavelength range without mixing with a foreign substance inside the sample.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a detection principle according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a detection principle according to an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an inspection system according to an embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of an inspection system according to an embodiment of the present invention.

5A is a diagram showing a moving direction of a sample during scanning by an X-ray beam, and FIG.
FIG. 7 is a diagram illustrating an example of a detection result of an attached foreign matter.

FIG. 6A is a diagram showing a moving direction of a sample during scanning by an X-ray beam, and FIG.
FIG. 7 is a diagram illustrating an example of a detection result of an attached foreign matter.

FIG. 7 is a diagram showing a difference between the detection result of FIG. 6B and the detection result of FIG. 6B.

FIG. 8 is a diagram showing an example of a detection result of a foreign substance inspection device using laser light.

FIG. 9 is a diagram showing a difference between the detection result of FIG. 7 and the detection result of FIG. 8;

FIG. 10 is a diagram showing a moving direction of a sample during scanning by an X-ray beam.

FIG. 11 is a schematic configuration diagram of an inspection system according to an embodiment of the present invention.

FIG. 12 is a diagram showing an example of a result of detection of attached foreign matter by the inspection system of FIG. 11;

[Explanation of symbols]

 Reference Signs List 10 X-ray beam irradiation system 20 X-ray beam detection system 30 Sample table 40 Moving mechanism 50 Controller

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Takashi Naito 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Hiroki Yamamoto 7-1 Omikamachi, Hitachi City, Ibaraki Prefecture No. 1 Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Mitsutoshi Honda 1-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory Hitachi Research Laboratory (72) Inventor Tetsuo Nakazawa Hitachi, Ibaraki Prefecture 7-1-1, Omikacho F-term in Hitachi Research Laboratory, Hitachi Ltd. F-term (reference) 2G001 AA01 AA07 BA15 CA01 CA07 CA10 DA05 DA06 DA10 EA02 EA09 GA13 JA06 JA07 KA03 LA06 MA05 PA11 PA12 PA15 SA02 2G051 AA42 AB01 AB06 AC02 BA10 CB05 DA07 DA08 EA08

Claims (4)

[The claims] 1. An inspection method for detecting a foreign substance in contact with an inspection surface of a sample through which visible light passes, and irradiating the inspection surface with an X-ray so as to form an angle smaller than a critical angle with the inspection surface. A process of relatively moving the X-ray and the inspection surface; and a process of relative movement between the X-ray and the inspection surface, based on a change in the intensity of the X-ray reflected on the inspection surface during the relative movement. An inspection method for detecting foreign matter in contact with an inspection surface. 2. The inspection method according to claim 1, further comprising: irradiating the inspection surface with light, detecting scattered light from the inspection surface side, and detecting foreign matter in the sample, An inspection method for detecting foreign matter in the sample based on foreign matter detected by irradiation and foreign matter detected by the X-ray irradiation. 3. An inspection apparatus for detecting foreign matter in a sample that transmits visible light, wherein the X-ray is irradiated on an outer surface of the sample so as to form an angle smaller than a critical angle with the outer surface. A first inspection unit that detects the intensity of the X-rays reflected on the outer surface; a second inspection unit that irradiates the sample with light to detect scattered light from the sample side; 2. An inspection apparatus, comprising: a moving unit configured to move the inspection unit relatively to the sample. 4. The inspection apparatus according to claim 3, wherein a foreign object that has come into contact with an outer surface of the sample based on a detection result of the first inspection unit and the second inspection unit during the relative movement by the moving unit. And a control unit for detecting foreign matter contained in the sample.