JP4411373B2 - Surface inspection apparatus and method - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a surface inspection apparatus and method capable of accurately measuring the height and size of a foreign substance on an inspection surface to be inspected. More specifically, the present invention relates to a surface inspection apparatus and method for inspecting a measurement object on a surface of a thin plate-like object such as a semiconductor wafer, for example, a foreign substance (particle or the like).
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is known an apparatus for inspecting foreign matter on a surface to be inspected by irradiating the surface of the object to be inspected with a light beam and receiving specular reflection light and scattered reflection light from the surface of each inspection object (wafer). ing.
[0003]
For example, Japanese Patent Laid-Open No. 56-67739 discloses a defect inspection apparatus that uses a plurality of coherent light beams incident from different directions as light beams.
[0004]
Japanese Patent Laid-Open No. 1-59522 discloses a circuit pattern in which a detection point is irradiated with a light beam of a polarized laser from obliquely upward in four directions around the detection point, and a specific deflection component is extracted from reflected light from the detection point. There has been disclosed a wafer foreign matter detection apparatus which detects foreign matter existing on a formed wafer.
[0005]
Assuming a semiconductor wafer as the inspection target, the inspection target (measurement target) includes foreign matter (generally convex) on the surface of the semiconductor wafer.
[0006]
[Problems to be solved by the invention]
In the conventional surface detection apparatus and method, there is a difference in the detection accuracy of the height of the foreign matter, depending on the type of inspection object. For example, when the inspection surface has waviness, the height of the foreign matter cannot be accurately detected. This is because the detected height differs between the upper part and the lower part of the swell even if the foreign matter has the same height.
[0007]
Even in such a case, it is desirable to more accurately inspect the height of the foreign matter under appropriate conditions for each inspection object.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide a surface detection apparatus and method capable of solving the disadvantages caused by the prior art and reducing errors in foreign object height detection.
[0009]
[Means for Solving the Problems]
The solution of the present invention is exemplified by the surface detection apparatus and method according to claims 1 to 14 described above.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The surface inspection apparatus of the present invention includes a light source, an illumination optical system that illuminates the inspection surface with a light beam from the light source at a predetermined inclination angle, a first light receiving optical system that receives scattered reflected light from the inspection surface, The first light receiving unit that receives the scattered reflected light received by the first light receiving optical system, the second light receiving optical system that receives the specular reflected light from the inspection surface, and the second light receiving optical system. Based on the first signal from the second light receiving part for receiving the specular reflection light and the first light receiving part, the size of the foreign matter on the inspection surface is obtained, and on the basis of the second signal from the second light receiving part, And a control operation unit for obtaining the height of the foreign matter on the inspection surface.
[0011]
The control calculation unit is configured to obtain the height of the foreign matter on the inspection surface based on the second signal when the size of the detected foreign matter is approximately equal to or larger than the diameter of the illumination light beam. Yes.
[0012]
Preferably, the control calculation unit obtains the height of the foreign substance from the change in position of the specular reflection light on the inspection surface, that is, the change in height data. For example, when the first signal from the first light receiving unit is equal to or higher than a predetermined slice level (also referred to as a threshold level; the same shall apply hereinafter), it is determined that there is a foreign object, and the first signal in the region where the presence of the foreign object is determined. The height of the foreign matter is obtained based on the two signals and the second signal around the area determined as the presence of the foreign matter.
[0013]
The height of the foreign matter is determined according to the average value of the positions of the front end and the rear end of the foreign matter in the second signal, and follows the waviness of the inspection surface.
[0014]
The control calculation unit is based on a difference in average value between data based on the second signal in the area determined to be the presence of foreign matter and data based on the second signal in an area around the area determined to be the presence of foreign matter. Find the height of the foreign material.
[0015]
In another embodiment of the present invention, a so-called pixel method is employed. For example, the control calculation unit divides the measurement target into pixels of a predetermined large number of unit areas, and the maximum value of the first signal and / or the second signal in each pixel is set as the value of each signal in the pixel. deal with.
[0016]
In addition, the control calculation unit may include data based on the second signal pixel-processed in the area determined to be the presence of the foreign substance, and data based on the second signal pixel-processed in the area around the area determined to be the presence of the foreign substance. The height of the foreign matter is obtained based on the difference between the average values.
[0017]
The control calculation unit determines the presence of a foreign object based on the first pixel-processed signal, and determines the presence of the foreign object based on each analog first signal and analog second signal in the pixel at the position determined as the presence of the foreign object. Find the height.
[0018]
The surface inspection method of the present invention includes a step of illuminating an inspection surface with a light beam at a predetermined inclination angle, a step of receiving scattered reflected light from the inspection surface to obtain a first signal, and a step from the surface to be inspected. Receiving a specular reflection light to obtain a second signal; obtaining a size of a foreign substance on the inspection surface based on the first signal; and the obtained size of the foreign substance is substantially equal to a diameter of the illumination light beam. If it is equal to or greater than that, a step of determining the height of the foreign matter on the inspection surface based on the second signal is included.
[0019]
Preferably, in the method, when the first signal is equal to or higher than a predetermined slice level, it is determined that foreign matter is present, and the second signal and foreign matter are determined to be present in a region where the foreign matter is determined to be present. The height of the foreign material is obtained based on the second signal around the area.
[0020]
The height of the foreign matter is determined according to the average value of the second signal in a predetermined range, and follows the waviness of the inspection surface.
[0021]
Based on the difference between the average values of the data based on the second signal in the area determined as the presence of the foreign object and the data based on the second signal in the area around the area determined as the presence of the foreign object, the height of the foreign object is determined. Ask.
[0022]
When the method of the present invention is implemented by the pixel method, the measurement object is divided into a large number of pixels of a predetermined unit area, and the maximum value of the first signal and / or the second signal in each pixel is determined by the pixel. As the value of each signal.
[0023]
Then, the difference between the average values of the data based on the second signal pixel-processed in the area determined to be the presence of the foreign object and the data based on the second signal pixel-processed in the area around the area determined to be the presence of the foreign object To determine the height of the foreign material.
[0024]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0025]
As schematically shown in FIG. 1, according to a preferred embodiment of the present invention, the surface inspection apparatus predetermines the inspection surface 3 a of the inspection object 3 with the light source 1 and the light flux 2 from the light source 1. The illumination optical system 4 that illuminates at an inclination angle, the first light receiving optical system 6 that receives the scattered reflected light 5 from the inspection surface 3a, and the scattered reflected light 5 received by the first light receiving optical system 6 are received. The first light receiving unit 7, the second light receiving optical system 9 that receives the specular reflected light 8 from the inspection surface 3a, and the second light receiving unit 10 that receives the specular reflected light 8 received by the second light receiving optical system 9. The size of a foreign substance (not shown) on the inspection surface 3a is obtained based on the first signal 12 from the first light receiving unit 7, and the inspection surface 3a is determined based on the second signal 13 from the second light receiving unit 10. And a control calculation unit 14 for obtaining the height of a certain foreign substance.
[0026]
When the calculated size of the foreign material is approximately equal to or larger than the diameter of the light beam 2 illuminated on the inspection surface, the control calculation unit 14 determines the height of the foreign material on the inspection surface 3a based on the second signal 13. I ask for it.
[0027]
In the embodiment of the height data HR method (a so-called high resolution method in which high-precision measurement is performed with high density) for obtaining the height of the foreign matter from the change in height data, the control calculation unit 14 is a first light receiving unit. When the first signal 12 from 7 is equal to or higher than a predetermined slice level, it is determined that there is a foreign object, and the second signal 13 in the area determined as the presence of the foreign object and the periphery of the area determined as the presence of the foreign object The height of the foreign material is obtained based on the second signal 13 at. The height of the foreign matter is determined according to the average value of the second signal 13 in a predetermined range, and follows the waviness of the inspection surface (including warp and other height changes).
[0028]
In addition, the control calculation unit 14 calculates the average value of the data based on the second signal 13 in the region where the presence of the foreign matter is determined and the data based on the second signal 13 in the region around the region where the presence of the foreign matter is determined. Based on the difference, the height of the foreign matter is obtained.
[0029]
In the surface inspection apparatus according to the present invention, in the embodiment employing the pixel method, the control calculation unit 14 divides the measurement object 3 into pixels of a predetermined large number of unit areas, and the first in each pixel. The maximum value of the signal 12 and / or the second signal 13 is treated as the value of each signal at that pixel.
[0030]
In this case, the control calculation unit 14 uses the second signal 13 pixel-processed in the area determined to be the presence of the foreign substance and the second signal pixel-processed in the area around the area determined to be the presence of the foreign substance. 13 is configured to obtain the height of the foreign matter based on the difference of the average value from the data of No. 13.
[0031]
Then, the control calculation unit 14 determines the presence of a foreign substance based on the pixel-processed first signal 12, and the analog first signal 12 and the analog second signal 13 in the pixel at the position where the foreign substance is determined to exist. Based on the above, the height of the foreign matter is obtained.
[0032]
The control calculation unit 14 includes a signal processing unit, and the signal processing result (the position, number, height, scattered light level, etc.) of the foreign matter is displayed on the display unit 15.
[0033]
Further, the control calculation unit 14 sends a control signal to the drive unit 16 to control the movement and rotation of the table 18 on which the measurement object 3 is placed in the X direction, the Y direction, and the Z (height) direction, as in the conventional case. It is configured.
[0034]
Further, the control calculation unit 14 operates the light source 1, the illumination optical system 4, the first light receiving optical system 6, the first light receiving unit 7, the second light receiving optical system 9, the second light receiving unit 10, and the measurement object 3. The robot arm drive unit (not shown) is also supplied with a processing signal for control.
[0035]
First embodiment (height data HR system)
First, an HR surface inspection apparatus and method for Z data (that is, height data) will be described.
[0036]
The Z data HR method is a method for obtaining the height of a foreign substance from a change in height data.
[0037]
In this method, height data is detected together with foreign substance peak information. In the case of a foreign substance having a size larger than the diameter of the light beam, the height information changes. Paying attention to this, the height of the foreign object is detected.
[0038]
When the height data HR method is employed, the apparatus shown in FIG. 1 is preferably a laser light source (helium neon) as a light source and has a wavelength of 633 nm. The illumination optical system 4 illuminates the inspection surface 3a with a light beam 2 from the light source 1 at a predetermined inclination angle (for example, 22 degrees). The first light receiving optical system 6 receives the scattered reflected light 5 from the inspection surface 3a. The first light receiving unit 7 receives the scattered reflected light 5 received by the first light receiving optical system 6. As this 1st light-receiving part 7, the light receiving element like a photomultiplier is preferable.
[0039]
The second light receiving optical system 9 receives the specular reflected light 8 from the inspection surface 3a. The second light receiving unit 10 receives the specular reflected light 8 received by the first light receiving optical system 9. The control calculation unit 14 obtains the size (outer edge) of the foreign substance on the inspection surface 3a based on the position coordinates of the first signal 12 from the first light receiving unit 7 exceeding a predetermined slice level, and the second light receiving unit. 10, the height of the foreign substance on the inspection surface 3 a is obtained based on the position where the light is incident, that is, based on the position of the output (peak) in the second signal 13. For example, a PSD or the like can be employed as the second light receiving unit 10.
[0040]
When the first signal 12 from the first light receiving unit 7 is equal to or higher than a predetermined slice level, the control calculation unit 14 determines the presence of a foreign substance, and the second signal 13 in the area determined to be the presence of the foreign substance and The height of the foreign matter is obtained based on the second signal 13 in the region around the region determined to be the presence of the foreign matter.
[0041]
Further, the control calculation unit 14 compares the difference between the average value of the data based on the second signal 13 in the area determined as the presence of the foreign object and the data based on the second signal 13 in the area around the area determined as the presence of the foreign object. The height of the foreign matter is determined based on the above.
[0042]
Further, the control calculation unit 14 is configured to change based on the data of the first signal 12 in a region where it is determined that no foreign matter exists. The diameter of the illumination light beam 2 from the illumination optical system 4 is set smaller than the size of the foreign object to be measured 3.
[0043]
FIG. 2 shows an outline of the processing procedure of the above-described height data HR type surface inspection apparatus.
[0044]
Please refer to FIG. Start surface inspection. That is, as is well known, the light source 1 is caused to emit light, the wafer (a typical example of the inspection object 3) is rotated, and the light flux 2 is irradiated from the light source 1 onto the inspection surface of the wafer 3.
[0045]
In the control calculation unit 14, the wafer height level is initially set. That is, the Z ₀ level is set. Further, the values of the first signal 12 and the second signal 13 are stored in the memory. Next, it is determined whether or not the first signal 12 exceeds a predetermined slice level (threshold level). If not exceeded (if no), proceed directly to the next. When it exceeds (when Yes), the values of the first signal 12 and the second signal 13 are stored and the process proceeds to the next.
[0046]
In Zs and Ss, an uppercase letter Z indicates a height, an uppercase letter S indicates a scatter level, a lowercase letter s indicates a start (start), and a lowercase letter e indicates an end (end).
[0047]
The first signal 12 determines the peak of the second signal 13. If Yes, the peak is stored as Zp, Sp (uppercase Z indicates height, uppercase S indicates scatter level, lowercase p indicates peak) and proceeds to the next. If no, continue to the next step.
[0048]
Next, it is determined whether or not the first slice level has been lowered. If yes, they are stored as Se, Ze (uppercase S indicates scatter level, uppercase Z indicates height, lowercase e indicates end (end)), and proceeds to the next. If no, continue to the next step.
[0049]
It is determined whether or not a predetermined period T ₀ has elapsed. If Yes, it is determined whether or not the predetermined inspection range has been completed. If No, the original first signal has exceeded a predetermined level. Return to the step of determining whether or not.
[0050]
When it is determined that the predetermined period T ₀ has elapsed (that is, when Yes), it is determined whether or not the predetermined inspection range has ended. If the answer is No, the process proceeds to the next after determining whether or not there is a foreign object in the previous period.
[0051]
When it is determined that the predetermined inspection range has ended, that is, when it is Yes, from the coordinate value (converted in time) of the scatter level (Ss) at the start and the scatter level (Se) at the end from the first signal 12 The foreign material width W is calculated. On the other hand, an average value of height (Z) data other than the height (Zs) at the start and the height (Ze) at the end of the predetermined time T ₀ is calculated from the second signal 13.
[0052]
After that, when the measurement is finished, “End” is set. When the measurement is not finished, the process returns to the first procedure (1).
[0053]
On the other hand, when the predetermined inspection range is not completed, that is, No, this corresponds to one unit obtained by dividing the measurement range by a signal from the encoder. It is determined whether or not there is a foreign object in the previous period. If No, the average value of the second signal 13 is calculated, and if Yes, the average value of the second signal 13 other than the foreign object (Zs−Ze). / 2 is obtained, and the average value Zth is subtracted from the peak position Zp of the signal 12, whereby the true foreign object height Zth can be obtained. When No, the average value of the second signal 13 is obtained and the process proceeds to the next.
[0054]
The operation of the HR method related to the control calculation unit 14 of FIG. 1 will be described with reference to FIG.
[0055]
In FIG. 4, an output signal 13 from the first light receiving unit 7 mainly including the presence / absence of the foreign matter and the foreign matter surface is sent through the first amplifier 21 and the first A / D converter 22 to the HR control calculation unit 23. Sent to. Further, the output signal 13 from the second light receiving unit 10 mainly including the position of the inspection surface 3a or the height information of the foreign matter is sent through the second amplifier 24 and the second A / D converter 25 to the HR control calculation unit. 23. The first A / D converter 22 and the second A / D converter 25 perform A / D conversion according to the clock signal 27 from the clock generator 26. The clock signal 28 from the clock generator 26 is also sent to the HR control calculator 23.
[0056]
The HR control calculation unit 23 outputs a control signal to the driving unit 16 to perform predetermined control of the motor 29 and the light source 1, while a signal including rotation information by the driving unit 16 (for example, rotating a wafer as a test object). A pulse signal) is received from the encoder unit 30 at every predetermined rotation of the motor 29 to be driven. The HR control calculation unit 23 exchanges data with the memory unit 31 as necessary. The HR control calculation unit 23 executes the processing shown in FIG. 2 and causes the display unit 33 to display a necessary display.
[0057]
Second embodiment (pixel method)
Next, a pixel type surface inspection apparatus and method will be described.
[0058]
In the above-described embodiment of the height data HR system, the Z value (height) is obtained at the point where the foreign object is present, and the surrounding Z value is unknown. However, the pixel-based embodiment allows for relative height measurements.
[0059]
In the case of the height data HR method, the Z value (height) of only the place where the data exists is taken in. However, in actuality, since waviness (including warpage or the like) is included, the height data of the foreign matter is inaccurate even if the Z value is close to the absolute value.
[0060]
However, when data is processed by the pixel method, it is possible to obtain a Z value (maximum value) even for a pixel having no foreign matter, and therefore it is highly possible that the value represents a nearby Z value.
[0061]
Therefore, by obtaining an average Z value of pixels having no foreign matter around the foreign matter to be measured, the error can be reduced and the height of the foreign matter can be obtained.
[0062]
True foreign object height Zth = Z value during measurement−peripheral average Z value The peripheral average Z value here will be described.
[0063]
Assuming that there are 3 vertical and 3 horizontal (9 total) pixel groups in a large number of pixels, only the pixels below the minimum detection value in the pixel group are targeted, and a maximum of 8 around the foreign object. An average of pixels or an average of about two pixels before and after only in the scanning direction is obtained.
[0064]
This peripheral pixel averaging method will be further described. If there is a foreign object in only one pixel located in the pixel group, the average object is the peripheral portion of the pixel. That is, the average is obtained from the remaining 8 pixels located around the center pixel having the peak. Pixels with foreign objects are excluded from the averaging process.
[0065]
Further, if there is a foreign substance in another pixel in the vicinity (that is, if there are foreign substances in a total of two pixels), these two pixels are excluded from the averaging process. The average of the remaining 7 pixels is processed.
[0066]
When there are a large number of pixels and the image is viewed only in a certain scanning direction, the average processing is performed for the peripheral pixels located only in the lateral direction of the pixel having the peak.
[0067]
In either case, the pixel size and 0.5mm Kaku, treated to eliminate the vertical height error.
[0068]
As for the diameter of the light beam and the influence of foreign matter, the height sensor preferably detects the change in the position of the light receiving barycenter by changing it to an electric quantity. Then, it is considered that the center of gravity is at a diameter within 90% of the intensity of the light beam. When a light beam having a diameter of 30 μm to 100 μm scans a foreign material, if the foreign material is 10 μm or more on a flat surface, the center of gravity can be sufficiently moved.
[0069]
It should be noted that the actual foreign matter shape has almost no flat surface related to light reflection, and the foreign matter shape varies. However, it is considered that there is a characteristic that a correct Z value (height) is output as the plane area increases.
[0070]
As schematically shown in FIG. 1, according to a preferred embodiment of the present invention, the surface inspection apparatus predetermines the inspection surface 3 a of the inspection object 3 with the light source 1 and the light flux 2 from the light source 1. The illumination optical system 4 that illuminates at an inclination angle, the first light receiving optical system 6 that receives the scattered reflected light 5 from the inspection surface 3a, and the scattered reflected light 5 received by the first light receiving optical system 6 are received. The first light receiving unit 7, the second light receiving optical system 9 that receives the specular reflected light 8 from the inspection surface 3a, and the second light receiving unit 10 that receives the specular reflected light 8 received by the second light receiving optical system 9. The size of a foreign substance (not shown) on the inspection surface 3a is obtained based on the first signal 12 from the first light receiving unit 7, and the inspection surface 3a is determined based on the second signal 13 from the second light receiving unit 10. And a control calculation unit 14 for obtaining the height of a certain foreign substance.
[0071]
When the calculated size of the foreign material is approximately equal to or larger than the diameter of the light beam 2 illuminated on the inspection surface, the control calculation unit 14 determines the height of the foreign material on the inspection surface 3a based on the second signal 13. I ask for it.
[0072]
The control calculation unit 14 divides the measurement object 3 into pixels of a predetermined large number of unit areas, and sets the maximum value of the first signal 12 and / or the second signal 13 in each pixel to the maximum value of each signal in the pixel. It is configured to be treated as a value.
[0073]
In this case, the control calculation unit 14 uses the second signal 13 pixel-processed in the area determined to be the presence of the foreign substance and the second signal pixel-processed in the area around the area determined to be the presence of the foreign substance. 13 is configured to obtain the height of the foreign matter based on the difference of the average value from the data of No. 13.
[0074]
Then, the control calculation unit 14 determines the presence of a foreign substance based on the pixel-processed first signal 12, and the analog first signal 12 and the analog second signal 13 in the pixel at the position where the foreign substance is determined to exist. Based on the above, the height of the foreign matter is obtained.
[0075]
With reference to FIG. 3, the process flow of the pixel type surface inspection will be briefly described. As in FIG. 2, uppercase Z is height, uppercase S is slice level (threshold level), lowercase s is start (start), lowercase e is end (end), and lowercase p is peak. Show.
[0076]
Start the operation. As is well known, the light source 1 emits light and the light beam 2 is irradiated onto the detection surface of the wafer. A semiconductor wafer (a typical example of an inspection target) is rotated and inspection is started.
[0077]
The control calculation unit 14 performs initial setting (setting of values at the start, end, and peak) for the slice level and height. In this example, the initial values of Sp, Zp, Ss, Zs, Se, and Ze are all set to zero.
[0078]
Next, the values of the first signal 12 and the second signal 13 are stored in the memory. Thereafter, it is determined whether or not the first signal exceeds the slice level. If Yes, Zs and Ss are stored. In the case of No, the process proceeds to a later process (described later) for determining the pixel end point.
[0079]
The peak value (Sp, Zp) is determined. If No, the process proceeds to a later step (described later) for determining the pixel end point. When Yes, it is determined whether or not those peak values are larger than the previous peak value. When the answer is Yes, the peak value is updated. When the answer is No, the process proceeds as it is.
[0080]
It is determined whether or not the first signal is below a predetermined slice level. When Yes, Se and Ze are stored, and when No, the process proceeds as it is.
[0081]
The pixel end point is determined. If No, the process returns to the step of storing the first signal and the second signal in the memory. If Yes, the peak value of the first signal and the second signal is used as the representative value of the pixel. Remember.
[0082]
Next, it is determined whether or not the inspection range has been completed. If No, the above initial setting (zero setting) is returned. If Yes, the number of consecutive pixels with a signal exceeding a predetermined slice level is calculated. Thus, the width W of the foreign matter is obtained, and the height Zth of the true foreign matter is obtained as the Z value during measurement−the peripheral average Z value.
[0083]
After that, it is determined whether or not to end, and if Yes, the process ends. If No, the process returns to the original start.
[0084]
The pixel-type operation related to the control calculation unit 14 of FIG. 1 will be described with reference to FIG.
[0085]
In FIG. 5, the output signal 13 from the first light receiving unit 7 mainly including the presence / absence of the foreign matter and the foreign matter surface is sent to the pixel control calculation unit 33 via the first amplifier 21 and the first A / D converter 22. Sent to. Further, the output signal 13 from the second light receiving unit 10 mainly including the position of the inspection surface 3a or the height information of the foreign matter is transmitted through the second amplifier 24 and the second A / D converter 25 to the pixel control calculation unit. 33. The first A / D converter 22 and the second A / D converter 25 perform A / D conversion according to the clock signal 27 from the clock generator 26. The clock signal 28 from the clock generator 26 is also sent to the pixel control arithmetic unit 33.
[0086]
The pixel control calculation unit 33 outputs a control signal to the drive unit 16 to perform predetermined control of the motor 29 and the light source 1, while a signal including rotation information by the drive unit 16 (for example, rotating a wafer as a test object). A pulse signal) is received from the encoder unit 30 at every predetermined rotation of the motor 29 to be driven. The pixel control calculation unit 33 exchanges data with the memory unit 31 as necessary. The pixel control calculation unit 33 executes the processing shown in FIG. 3 and causes the display unit 33 to display a necessary display.
[0087]
Third embodiment (combination of pixel method and HR method)
In one control calculation unit 14, it is possible to implement the first embodiment and the second embodiment in combination.
[0088]
【The invention's effect】
According to the present invention, scattered reflected light and specular reflected light from a foreign object can be received by the respective light receiving portions (light receiving elements), and the size and height of the foreign object can be accurately measured from these signals.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing an example of a surface inspection apparatus according to the present invention.
FIG. 2 is a flowchart showing a processing procedure of the height data HR surface inspection apparatus according to the present invention.
FIG. 3 is a flowchart showing a processing procedure of the pixel type surface inspection apparatus according to the present invention.
4 is a block diagram schematically showing the configuration of an HR method related to the control calculation unit of FIG. 1;
5 is a block diagram schematically showing the configuration of a pixel method related to the control calculation unit of FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Light source 2 Light beam 3 Measuring object 3a Inspection surface 4 Illumination optical system 5 Scattered reflected light 6 1st light-receiving optical system 7 1st light-receiving part 8 Specular reflection light 9 2nd light-receiving optical system 10 2nd light-receiving part 12 1st signal 13 1st 2 signals 14 control operation unit 15 display unit 16 drive unit 18 table 21 first amplifier 22 first A / D converter 23 HR control operation unit 24 second amplifier 25 second A / D converter 26 clock generation unit 27 clock signal 28 clock Signal 29 Motor 30 Encoder part 31 Memory part 33 Display part

Claims (8)

A light source;
An illumination optical system that illuminates the inspection surface at a predetermined inclination angle with the light flux from the light source;
A first light receiving optical system for receiving the scattered reflected light from the inspection surface;
A first light receiving unit that receives the scattered reflected light received by the first light receiving optical system;
A second light receiving optical system for receiving the specular reflected light from the inspection surface;
A second light receiving portion for receiving the specular reflected light received by the second light receiving optical system;
Control calculation for obtaining the size of the foreign matter on the inspection surface based on the first signal from the first light receiving portion, and obtaining the height of the foreign matter on the inspection surface based on the second signal from the second light receiving portion. And
The control calculation unit determines the height of the foreign matter on the inspection surface based on the second signal when the size of the obtained foreign matter is approximately equal to or larger than the diameter of the light beam illuminated on the inspection surface. A surface inspection apparatus characterized by being configured to obtain. The surface inspection apparatus according to claim 1,
When the first signal from the first light receiving unit is equal to or higher than a predetermined slice level, the control calculation unit determines the presence of a foreign substance, and the second signal and the foreign substance in a region determined to be the presence of the foreign substance. A surface inspection apparatus configured to obtain a height of a foreign substance based on a second signal around a region determined to be present. In the surface inspection apparatus according to claim 2,
The surface inspection apparatus, wherein the predetermined slice level is determined according to an average value of the first signal in a predetermined range, and is configured to follow the undulation of the first signal. In the surface inspection apparatus according to claim 2,
The control calculation unit is based on a difference in average value between data based on the second signal in the area determined to be the presence of foreign matter and data based on the second signal in an area around the area determined to be the presence of foreign matter. A surface inspection apparatus configured to obtain the height of a foreign object. Illuminating the inspection surface with a light beam at a predetermined inclination angle;
Receiving scattered reflected light from the inspection surface to obtain a first signal;
Receiving specular reflected light from the surface to be inspected to obtain a second signal;
Determining the size of foreign matter on the inspection surface based on the first signal;
Determining the height of the foreign matter on the inspection surface based on the second signal when the size of the obtained foreign matter is approximately equal to or greater than the diameter of the light beam illuminated on the inspection surface. A surface inspection method characterized by the above. When the first signal is equal to or higher than a predetermined slice level, it is determined that there is a foreign object, and the second signal in the area determined as the presence of the foreign object and the second signal around the area determined as the presence of the foreign object. 6. The surface inspection method according to claim 5 , wherein the height of the foreign matter is obtained based on the signal. The surface inspection method according to claim 6 ,
The surface inspection method according to claim 1, wherein the predetermined slice level is determined according to an average value of the first signal in a predetermined range, and follows the undulation of the first signal. The surface inspection method according to claim 6 ,
Based on the difference between the average values of the data based on the second signal in the area determined as the presence of the foreign object and the data based on the second signal in the area around the area determined as the presence of the foreign object, the height of the foreign object is determined. A surface inspection method characterized by being obtained.

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