JP6476580B2 - Flat plate surface condition inspection apparatus and flat plate surface condition inspection method using the same - Google Patents

Description

  The present invention light scatters abnormal surface conditions such as foreign matter, scratches, and crystal defects adhering to the surface of a flat substrate such as a semiconductor wafer, mask, disk substrate, liquid crystal substrate, glass substrate, and transparent film. The present invention relates to a technique for inspecting the surface state of a flat substrate, in particular, a method for detecting the surface state of a flat substrate, in particular for discriminating and checking defects in the surface of the flat substrate such as crystal defects, scratches, slips, watermarks, and stacking faults And a flat substrate surface state inspection apparatus using the method.

  If even a small amount of foreign matter (dust or defect) is present on a substrate on which an electronic device or the like is formed, it may lead to generation of a defective product, and thus inspection of the foreign matter and surface state of the substrate is indispensable. In addition, the inspection of the surface condition of the substrate is aimed at identifying the cause of the occurrence of defects in the manufacturing process of the electronic device along with the removal of defective products. For this purpose, the type and size of detected defects are known. It becomes important.

Defect types generated on a flat substrate such as a semiconductor wafer include foreign matter, scratches, cracks, etc., crystal defects, slips, polishing scratches (scratches), circular patterns of silica (watermarks), stacking faults, spherical foreign matters, etc. can give. Here, crystal defects, slips, and scratches are concave defects, while spherical foreign substances, watermarks, and stacking faults can be classified as convex defects.

Inspecting the surface state of a flat substrate involves irradiating the substrate surface with laser light with good directivity, detecting scattered light reflected from the substrate surface with a scattered light receiver, and scanning the laser light irradiation point two-dimensionally. A method for inspecting the entire substrate surface is generally used. For example, in the foreign matter inspection apparatus for a transparent flat substrate described in Patent Document 1 below, the transparent flat substrate is irradiated with detection light by a light projecting system, and scattered light due to the foreign matter existing on the transparent flat substrate is received by a light receiving system. In the foreign matter inspection apparatus for detecting foreign matter existing on the transparent flat plate substrate, the foreign flat plate substrate is provided on one surface (hereinafter referred to as a front surface) of the transparent flat plate substrate at a predetermined incident angle with respect to the substrate normal of the transparent flat plate substrate. A light projecting system for irradiating the surface with the detection light; and the light receiving system provided on the surface side and provided at a position opposite to the light projecting system with respect to the irradiation point of the detection light. In the light receiving system, the first scattered light generated when the detection light irradiated from the light projecting system is irradiated on the foreign matter on the surface, and the detection light is transmitted through the transparent flat plate substrate, Foreign matter present on the other side (hereinafter, back side) A condensing lens that condenses the second scattered light generated when irradiated, and an optical that separates the first scattered light and the second scattered light from the condensing lens into two paths, respectively. A transparent flat plate comprising: an element; a first scattered light receiving sensor that receives the first scattered light; and a second scattered light receiving sensor that receives the second scattered light. A foreign matter inspection apparatus for a substrate is disclosed.

  A foreign matter inspection apparatus described in Patent Literature 1 includes a pair of scattered light irradiation / light reception systems including a projector that emits laser light that is detection light and a light receiving sensor that receives scattered light from the foreign matter irradiated with the laser light. Is scanned in the X and Y directions to inspect foreign matter and the like adhering to the substrate. However, in the technology disclosed in Patent Document 1, it can be seen from the scattered light that there is some abnormality in the surface state of the wafer, but it cannot be distinguished whether they are convex defects or concave defects. There's a problem.

Patent Document 2 discloses a technique for irradiating a substrate with laser light from a plurality of directions. Patent Document 2 discloses a plurality of projectors that irradiate the surface of a test object with a plurality of laser beams from different angles and a scattered light intensity corresponding to the scattered light intensity by detecting scattered light from a foreign substance at the same point. The present invention relates to a foreign substance inspection apparatus including a detector that detects a signal. The technique disclosed in Patent Document 2 irradiates laser light to the same point from a plurality of laser light sources and irradiates the same point with laser light, thereby increasing the scattered light intensity to a level that can be detected by the detector. It is an object. For this reason, even in the technique disclosed in Patent Document 2 and the technique disclosed in Patent Document 1, even if it can be detected that there is an abnormality in the surface state of the wafer, it is a convex defect or a concave shape. There is a problem that it is impossible to identify whether the defect is a defect.

Japanese Unexamined Patent Publication No. 2013-140061 Japanese Patent Laid-Open No. 11-258157

As described above, in the technique of inspecting the surface state of the transparent flat plate substrate using the conventional scattered light, it has not been possible to distinguish whether the abnormality occurring in the surface state is convex or concave. . Therefore, for example, in which process during the electronic device manufacturing process, what kind of defect has occurred cannot be specified.

Accordingly, an object of the present invention is to provide a surface state inspection method for a flat substrate that can identify the type of defect that has occurred in, for example, a flat substrate on which an electronic device or the like is formed, and a surface state inspection device that uses the method. It is in.

In order to solve the above-described problem, the invention according to claim 1 scans the surface of the flat substrate placed on the stage with the detection light irradiated by the light projecting system and at the predetermined interval in the scanning direction. The scattered light from the surface is detected by a light receiving system while being sent in an axial direction orthogonal to the surface, and the detected defect signal on the surface of the flat substrate is either a concave defect or a convex defect by an output signal from the detected light receiving system. In the flat substrate surface condition inspection device that inspects whether there is,
A light projecting system that irradiates an irradiation point with the detection light at a predetermined incident angle with respect to a substrate normal of the flat substrate to the surface of the flat substrate;
A light receiving system provided in a space opposite to the light projecting system with respect to the substrate normal, and receiving the scattered light;
A plurality of scattered light detectors for detecting scattered light received by the light receiving system;
A light receiving range limiting means for limiting a light receiving range so that the same scattered light does not enter each of the scattered light detectors;
The scanning light on the concave defect or the convex defect on the detection light is used to compare time waveforms representing changes in scattered light intensity detected by the plurality of scattered light detectors, and the defect type of the flat substrate is a concave defect or A flat plate substrate surface state inspection apparatus, comprising: a waveform comparison / determination unit that determines which of the convex defects is present.

  According to a second aspect of the present invention, there is provided the flat substrate surface state inspection apparatus according to the first aspect, wherein the irradiation point is connected to a lower end portion of the light receiving port of the light receiving system that receives the scattered light. The light receiving system is set so that an angle with respect to the substrate normal at that time is smaller than an angle with respect to the substrate normal of specularly reflected light from the irradiation point.

  A third aspect of the present invention is the flat substrate surface state inspection apparatus according to the first aspect, wherein the plurality of scattered light detectors are provided in the light receiving system and divide the scattered light. Two scattered light detectors for detecting each of the scattered lights separated by the above-described method.

The invention described in claim 4 scans the surface of the flat substrate placed on the stage with the detection light irradiated by the light projecting system, and sends it in an axial direction orthogonal to the scanning direction at a predetermined interval. However, a flat substrate that detects scattered light from the surface by a light receiving system and inspects whether the defect type on the surface of the flat substrate is a concave defect or a convex defect by an output signal from the detected light receiving system In the surface condition inspection apparatus of
A light projecting system that irradiates an irradiation point with the detection light at a predetermined incident angle with respect to a substrate normal of the flat substrate to the surface of the flat substrate;
A first light receiving system provided in a space opposite to the light projecting system with respect to the substrate normal, and receiving the scattered light;
In the surface side, is provided on the irradiation point of the detection light, provided in the second light receiving system and the light receiving system for receiving the scattered light, the before and Symbol scattered light detector of the first light receiving system first A light receiving range limiting means for limiting a light receiving range so that the same scattered light does not enter the scattered light detector of the two light receiving systems ;
A change in scattered light intensity detected by the scattered light detector of the first light receiving system and the scattered light detector of the second light receiving system is detected by scanning the detection light on the concave defect or convex defect. A surface state inspection apparatus for a flat plate substrate, comprising: a waveform comparison and determination unit that compares time waveforms to be expressed and determines whether a surface defect of the flat plate substrate is a concave defect or a convex defect. .

A fifth aspect of the present invention is the flat substrate surface state inspection apparatus according to the fourth aspect, wherein the irradiation point is connected to the lower end of the light receiving port of the light receiving system that receives the scattered light. The light receiving system is set so that an angle with respect to the substrate normal at that time is smaller than an angle with respect to the substrate normal of specularly reflected light from the irradiation point.

The invention according to claim 6 scans the surface of the flat substrate placed on the stage with the detection light irradiated by the light projecting system and sends it in an axial direction perpendicular to the scanning direction at a predetermined interval. However, a flat substrate that detects scattered light from the surface by a light receiving system and inspects whether the defect type on the surface of the flat substrate is a concave defect or a convex defect by an output signal from the detected light receiving system In the surface state inspection method, the surface of the flat substrate is irradiated with the detection light at a predetermined incident angle with respect to the normal of the flat substrate,
The substrate method when the irradiation point is provided in a space opposite to the light projecting system with respect to the substrate normal, and the lower end portion of the light receiving port for receiving the scattered light of the light receiving system is connected. Adjusting the angle relative to the substrate normal of the light receiving system so as not to receive specularly reflected light from the irradiation point,
The scattered light detector that detects the scattered light received by the light receiving system is limited to a light receiving range so that the scattered light entering from the light receiving port does not overlap and enter.
By comparing the time waveform representing a change in scattered light intensity detected by the plurality of scattered light detectors by scanning the concave light or the convex defect of the detection light,
A method for inspecting a surface state of a flat substrate, comprising determining whether the surface defect of the flat substrate is a concave defect or a convex defect.

  A seventh aspect of the invention is the surface state inspection method for a flat substrate according to the sixth aspect, wherein the scattered light is split into two by a half mirror, and the intensity of each scattered light is scattered into two It detects with a photodetector.

The invention according to claim 8 scans the surface of the flat substrate placed on the stage with the detection light irradiated by the light projecting system, and sends it in the axial direction perpendicular to the scanning direction at predetermined intervals. However, a flat substrate that detects scattered light from the surface by a light receiving system and inspects whether the defect type on the surface of the flat substrate is a concave defect or a convex defect by an output signal from the detected light receiving system In the surface condition inspection method of
Irradiating the irradiation point with the detection light at a predetermined incident angle with respect to the substrate normal of the flat substrate on the surface of the flat substrate;
Provided in the space opposite to the light projecting system with respect to the substrate normal, and with respect to the substrate normal when the irradiation point and the lower end of the scattered light receiving port of the light receiving system are connected Receiving the scattered light by a first light receiving system whose angle is set so as not to receive specularly reflected light from the irradiation point;
On the surface side, the scattered light is received by a second light receiving system that is provided on the irradiation point of the detection light and receives the scattered light,
A change in scattered light intensity detected by the scattered light detector of the first light receiving system and the scattered light detector of the second light receiving system is detected by scanning the detection light on the concave defect or convex defect. Compare the time waveforms that represent
A method for inspecting a surface state of a flat substrate, comprising determining whether a surface defect of the flat substrate is a concave defect or a convex defect.

  According to the present invention, it is possible to provide a surface state inspection method for a flat substrate that can identify a defect type of a flat substrate that could not be detected conventionally, and a surface state inspection device that uses the method. Thereby, for example, it is possible to identify the cause of failure in a semiconductor manufacturing process such as an electronic device, and to improve the manufacturing process of the semiconductor device or the like.

It is the figure which showed the structure of the surface state inspection apparatus which is one embodiment of this invention. FIG. 6 is a diagram showing how scattered light is generated when a detection light 11 is irradiated to a concave defect when there is a fine concave defect on the surface of the flat substrate 100. FIG. 6 is a diagram showing how scattered light is generated when a detection light 11 is irradiated on a convex defect when there is a fine convex defect on the surface of the flat substrate 100. FIG. 5 is a diagram showing how scattered light enters a scattered light detector when the detection light 11 is irradiated on the concave defect when the surface of the flat substrate 100 has a fine concave defect. is there. In the case where there is a fine convex defect on the surface of the flat substrate 100, it is shown how the scattered light enters the scattered light detector when the detection light 11 is irradiated to the convex defect. FIG. It is the figure which showed the structure of the surface state inspection apparatus 2 of the flat substrate which is one Example of this invention. It is the figure which showed the result of having test | inspected with the surface state inspection apparatus 2 of the flat substrate about the defect kind (concave defect, convex defect) of the wafer 102 of silicon carbide. It is the figure which showed the one part waveform output from the detector 30 of the surface state inspection apparatus 2 of a flat substrate, and the detector 40. FIG. It is the figure which showed the one part waveform output from the detector 30 of the surface state inspection apparatus 2 of a flat substrate, and the detector 40. FIG. It is the figure which showed the result of having confirmed the concave defect of the wafer 102 with the laser microscope based on the result inspected for the defect kind (concave defect) of the wafer 102 shown in FIG. It is the figure which showed the result of having confirmed the convex defect of the wafer 102 with the laser microscope based on the result by which the defect kind (convex defect) of the wafer 102 shown in FIG. 7 was test | inspected. It is the figure which showed the structure of the surface state inspection apparatus 3 of the flat substrate which is the 2nd Embodiment of this invention. It is the figure which showed the structure of the surface state inspection apparatus 4 of the flat substrate which is the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. FIG. 1 is a diagram showing a configuration of a flat substrate surface condition inspection apparatus 1 according to an embodiment of the present invention. The surface of the flat substrate 100 is irradiated with detection light (laser light) 11 from a laser light source 110 constituting the light projecting system 10 at a predetermined incident angle θ with respect to the normal 101 to the substrate. As a result, the specularly reflected light 12 and scattered light 13, 14, 15 from the flat plate substrate 100 enter the light receiving system 20 from the light receiving port 210 constituting the light receiving system 20. Note that the reflection angle of the specularly reflected light with respect to the substrate normal 101 is θ.

The inclination angle of the light receiving system 20 is adjusted so that the regular reflection light 12 does not enter the light receiving opening 210. In FIG. 1, the regular reflected light 12 is received by the light receiving system 20 by setting the angle with respect to the normal 101 when the irradiation point 90 and the lower end of the light receiving opening 210 are connected to an angle (θ ₁ ) smaller than θ. Is set not to receive light. Here, in the description of this embodiment, scattered light that enters the light receiving system 20 enters the lower end of the light receiving opening 210 and scattered light that enters the upper end of the light receiving opening 210. The entire scattered light between the scattered light 14 and the scattered light 15 is defined as the scattered light 13.

In FIG. 1, the scattered light 14 entering from the light receiving opening 210 enters the lens barrel 220 from the lens barrel 200 and is shielded by a mask 240 which is a light shielding means. On the other hand, the scattered light 14 dispersed by the half mirror 50 provided in the lens barrel 200 enters the lens barrel 221 and enters the scattered light detector 231.

In the flat substrate surface state inspection apparatus 1, about half of the scattered light 13 scattered light on the scattered light 14 side enters the scattered light detector 231, and the other scattered light 13 (on the scattered light 15 side). About half of the scattered light) enters the scattered light detector 230. From the scattered light detector 230 and the scattered light detector 231, a waveform of an output signal (electric signal) corresponding to the intensity of the received scattered light is output. In addition, when the irradiation point 90 is a mirror surface, scattered light is not generated and only the regular reflection light 12 is obtained.

FIG. 2 is a view showing a state of scattered light generated when the detection light 11 is irradiated from the laser light source 110 onto the concave defect 91 of the flat substrate 100 having no foreign matter or defect. Here, FIG. 2A shows scattered light 14, scattered light 15, and scattered light generated when the detection light 11 is irradiated from the laser light source 110 onto the downward surface (right shoulder downward surface) of the concave defect 91 of the flat substrate 100. It is the figure which showed a mode that the light 13 produced.

Of the scattered light generated when the detection light 11 is irradiated on the downward surface (lower shoulder surface) of the concave defect 91, the intensity of the scattered light on the scattered light 14 side is strong and goes to the scattered light 15 side (counterclockwise). It has been found for the first time in the present invention that the intensity of scattered light becomes weaker in accordance with the direction).

FIG. 2B shows scattered light 14-1, scattered light 15-1, scattered light generated when the detection light 11 is irradiated from the laser light source 110 to the rising surface (right shoulder rising surface) of the concave defect 91 of the flat substrate 100. It is the figure which showed a mode that the light 13 produced. Of the scattered light generated when the detection light 11 is irradiated on the upward surface (upwardly rising surface) of the concave defect 91, the intensity of the scattered light on the scattered light 14-1 side is strong and goes to the scattered light 15-1 side ( It was discovered for the first time in the present invention that the intensity of the scattered light 13 becomes weaker in the clockwise direction.

FIG. 3 is a diagram showing a state of scattered light generated when the detection light 11 is irradiated from the laser light source 110 onto the convex defect 92. Here, FIG. 3A shows that the scattered light 14, the scattered light 15, and the scattered light 14 are generated when the detection light 11 is irradiated on the upward surface (right shoulder upward surface) of the convex defect 92 of the flat substrate 100. It is the figure which showed a mode. When the detection light 11 is irradiated on the upward surface (right shoulder upward surface) of the convex defect 92, the intensity of the scattered light on the scattered light 14 side is strong and goes to the scattered light 15 side (clockwise direction). It was found for the first time in the present invention that the intensity of the scattered light 13 becomes weaker in accordance with ().

FIG. 3B shows scattered light 14-1, scattered light 15-1 generated when the detection light 11 is irradiated from the laser light source 110 onto the down surface (right shoulder-down surface) of the convex defect 92 of the flat substrate 100. It is the figure which showed a mode that the scattered light 13 produced. The intensity of the scattered light generated when the detection light 11 is irradiated on the downward surface (right shoulder downward surface) of the convex defect 92 is scattered as it goes toward the scattered light 15-1 (counterclockwise direction). It has been found for the first time in the present invention that the intensity of the light 13 becomes weak.

  FIG. 4 shows how the scattered light generated by irradiating the fine concave defects on the surface of the flat substrate 100 with the detection light 11 by the flat substrate surface state inspection apparatus 1 is the scattered light detector 230 and the scattered light detector 231. It is the figure which showed whether it enters into.

  As shown in FIG. 4A, the scattered light 16 dispersed by the half mirror 50 enters the scattered light detector 231, but the scattered light 16 transmitted through the half mirror 50 is blocked by the mask 240 and scattered light detector. 230 does not enter. That is, the scattered light 13 on the scattered light 16 side enters the scattered light detector 231, and the scattered light 13 on the scattered light 17 side enters the scattered light detector 230.

  The flat substrate 100 is moved, and the detection light 11 is scanned from the descending surface of the concave defect 91 to the ascending surface (upwardly rising surface) of the recessed defect 91. FIG. 4B shows how the scattered light incident on the surface) enters the scattered light detector 230 and the scattered light detector 231. As shown in FIG. 4B, when the detection light 11 is irradiated on the climbing surface (upwardly rising surface) of the concave defect 91, the scattered light 19 at the upper end of the light receiving opening 210 is detected as scattered light. The light enters the device 230. On the other hand, the scattered light 19 dispersed by the half mirror 50 is blocked by the mask 241 and does not enter the scattered light detector 231. On the other hand, of the scattered light 18 from the lower end of the light receiving opening 210, the scattered light 18 dispersed by the half mirror 50 enters the scattered light detector 231, but the scattered light 18 transmitted through the half mirror 50 is The scattered light detector 230 is shielded by the mask 240 and does not enter.

  When the detection light 11 is irradiated onto the concave defect 91 in this way, and the detection light 11 is scanned from the downward surface (right shoulder-lowering surface) to the upward surface (right-shoulder upward surface) of the concave defect 91, the scattered light is scattered. FIG. 4C shows waveforms that appear in the detector 230 and the scattered light detector 231. When comparing the waveform of the electrical signal output from the scattered light detector 230 and the scattered light detector 231 when the concave defect 91 is irradiated with the detection light, first, the detected waveform of the scattered light appears in the scattered light detector 231. Thereafter, a detection waveform similar to that appears in the scattered light detector 230. This is because the intensity of the scattered light 13 on the scattered light 16 side is stronger than the scattered light 13 on the scattered light 17 side shown in FIG. 4 (c) is output from the scattered light detector 231, and when the detection light is irradiated on the surface that rises to the right as shown in FIG. 4 (b), the scattered light 19 side Since the scattered light 13 becomes stronger than the scattered light 13 on the scattered light 18 side, the waveform of the signal output from the scattered light detector 231 becomes similar to that of the signal output from the scattered light detector 231. It is because it outputs. It is waveform comparison determination means (not shown) that determines the type of defect type by comparing the waveforms of the detector 230 and the detector 231. The waveform comparison / determination means may be any means that can perform waveform comparison, such as a commonly used waveform checker or waveform determination digitizer.

FIG. 5 shows how the scattered light enters the scattered light detector when the convex defect is irradiated with the detection light 11 when the surface of the flat substrate 100 has a minute convex defect. FIG.

As shown in FIG. 5A, when the detection light 11 is irradiated on the rising surface (right shoulder rising surface) of the convex defect 92, the scattered light on the scattered light 16-1 side is caused by the half mirror 50. The dispersed scattered light 16-1 enters the scattered light detector 231, but the scattered light 16-1 transmitted through the half mirror 50 is blocked by the mask 240 and does not enter the scattered light detector 230. On the other hand, the scattered light 13 on the scattered light 17-1 side enters the scattered light detector 230, but the scattered light 17-1 dispersed by the half mirror 50 is blocked by the mask 241 and enters the scattered light detector 231. Does not shine.

  How is the scattered light detected when the flat substrate 100 is moved and the detection light 11 is scanned from the up surface of the convex defect 92 to the down surface of the convex defect 92 (downwardly facing surface)? FIG. 5B shows whether the light 230 enters the scattered light 231. As shown in FIG. 5 (b), when the detection light 11 is irradiated on the downward surface (the surface on the right shoulder) of the convex defect 92, the scattered light 18-1 is shielded by the mask 240 and the scattered light is detected. The scattered light 18-1 split by the half mirror 50 enters the scattered light detector 231, although it does not enter the device 230. On the other hand, the scattered light 19-1 entering the upper end of the light receiving opening 210 enters the scattered light detector 230, but the scattered light 19-1 dispersed by the half mirror 50 is shielded by the mask 241. It does not enter the scattered light detector 231.

  When the detection light 11 is irradiated onto the convex defect 92 in this way and the detection light is scanned from the upward surface (right shoulder rising surface) to the downward surface (right shoulder downward surface) of the convex defect 92, the scattered light is scattered. FIG. 5C shows waveforms that appear in the detector 230 and the scattered light detector 231. When the waveform of the signal output from the scattered light detector 230 and the scattered light detector 231 is compared when the convex defect 92 is irradiated with the detection light 11, the scattered light waveform first appears in the scattered light detector 230. Thereafter, it was found that a similar waveform appeared in the scattered light detector 231. This is detected on the upwardly rising surface of the convex defect 92 because the intensity of the scattered light on the scattered light 17-1 side is stronger than the scattered light 13 on the scattered light 16-1 side shown in FIG. When the light is irradiated, a signal as shown in FIG. 5C is output from the scattered light detector 230, and when the detection light comes to radiate to the surface that rises to the right as shown in FIG. 5B. Since the scattered light 13 on the scattered light 18-1 side is stronger than the scattered light 13 on the scattered light 19-1 side, a signal waveform as output from the scattered light detector 230 is output from the scattered light detector 231. .

  FIG. 6 is a diagram showing a configuration of a flat substrate surface state inspection apparatus 2 according to an embodiment of the present invention. The flat substrate surface state inspection apparatus 2 shown in FIG. 6 includes a laser light source 110 that constitutes a light projecting system, a light receiving port 70 that constitutes a light receiving system, a half mirror 50 that splits scattered light incident from the light receiving port 70, and a half A detector 30 for detecting scattered light separated by the mirror 50, a detector 40, a slit 32 for limiting the range of scattered light entering the detector 30 or the detector 40, a slit 42, and a slit 32, a slit 42 A mask 31 and a mask 41 are provided to block part of the scattered light from the light. The flat substrate surface condition inspection apparatus 2 includes an XY stage 80 that moves the flat substrate 100 in the X-axis-Y-axis direction, and a height control variation sensor 60 that controls the heights of the light projecting system and the light receiving system. Although waveform comparison / determination means is provided, it is not shown.

FIG. 7 is a view showing a result of inspecting a defect type (concave defect, convex defect) of the silicon carbide wafer 102 by the flat substrate surface condition inspection apparatus 2 described above. ● represents a convex defect, and x represents a concave defect.

FIG. 8 is a diagram showing waveforms of output signals output from the detector 30 and the detector 40 of the surface state inspection apparatus 2 for the flat substrate. A waveform as shown in FIG. 8 was detected from the position of x on the wafer 102 shown in FIG. When such a waveform is detected, the defect type is a concave defect as described above.

FIG. 9 is a diagram showing a part of waveforms output from the detector 30 and the detector 40 of the surface state inspection apparatus 2 for the flat substrate. A waveform as shown in FIG. 9 was detected from the position of ● on the wafer 102 shown in FIG. When such a waveform is detected, the defect type there is a convex defect as described above.

FIG. 10 shows the result of confirming the concave defect of the wafer 102 by the laser microscope based on the result of the inspection of the defect type of the wafer 102 shown in FIG. 7 by the surface state inspection apparatus 2 of the flat substrate. As a result, the concave defect of the wafer 102 by the surface state inspection apparatus 2 for the flat plate substrate and the concave defect of the wafer 102 by the laser microscope almost coincided.

Similarly, FIG. 11 shows the result of confirming the convex defect of the wafer 102 by the laser microscope. As a result, the convex defect of the wafer 102 by the flat substrate surface state inspection apparatus 2 and the convex defect of the wafer 102 by the laser microscope almost coincided.

  FIG. 12 is a diagram showing the configuration of the flat substrate surface condition inspection apparatus 3 according to the second embodiment of the present invention. The flat substrate surface state inspection apparatus 3 shown in FIG. 12 has two scattered light detectors 330 a and 330 b at the end of the lens barrel 320, and approximately half of the scattered light 13 counterclockwise from the lower side of the light receiving port 310. The scattered light detector 330a receives light, and the scattered light detector 330b receives approximately half of the scattered light 13 clockwise from the upper side of the light receiving port 310. Note that the slit 41 is configured to limit the field of view of the detector 330a and the detector 330b.

FIG. 13 is a diagram showing the configuration of a flat substrate surface condition inspection apparatus 4 according to the third embodiment of the present invention. The flat substrate surface condition inspection apparatus 4 shown in FIG. 13 irradiates the surface of the flat substrate 100 with the detection light 11 from the laser light source 110 at a predetermined incident angle with respect to the normal of the flat substrate, and the normal to the substrate normal. Then, the scattered light 13 is received by the first light receiving system 400 set so as not to receive the specularly reflected light from the irradiation point in the space opposite to the laser light source 110, and the received scattered light 13 is detected by the detector 1400. To do. In addition, a second light receiving system 410 that receives the scattered light 13-1 is provided substantially above the irradiation point of the detection light 11, and the scattered light 13-1 is detected by the scattered light detector 1410. Then, the waveforms of the output signals from the scattered light detectors 1400 and 1410 which are the waveforms of the scattered light intensity detected by the first light receiving system 400 and the second light receiving system 410 are compared, and the surface of the flat plate substrate is compared. It is determined whether the defect type is concave or convex.

1 2 3 4 Flat substrate surface condition inspection apparatus 10 Light projection system 20 Light reception system 12 Regular reflection light 13 14 15 16 17 18 19 Scattered light 41 Slit 50 Half mirror 80 XY stage 90 Irradiation point 91 Concave defect 92 Convex defect 100 Flat substrate 101 Substrate normal 102 Wafer 110 Laser light source 200 220 221 Lens barrel 210 Light receiving port 240 241 Mask 230 231 330a 330b Scattered light detector 1400 Light receiving system

Claims (8)

The surface of the flat substrate placed on the stage is scanned with the detection light irradiated by the light projecting system, and the scattered light from the surface is received while being sent at a predetermined interval in the axial direction perpendicular to the scanning direction. In the surface state inspection apparatus for the flat plate substrate for inspecting whether the defect type on the surface of the flat plate substrate is a concave defect or a convex defect, based on the detected output signal from the light receiving system,
A light projecting system that irradiates an irradiation point with the detection light at a predetermined incident angle with respect to a substrate normal of the flat substrate to the surface of the flat substrate;
A light receiving system provided in a space opposite to the light projecting system with respect to the substrate normal, and receiving the scattered light;
A plurality of scattered light detectors for detecting scattered light received by the light receiving system;
A light receiving range limiting means for limiting a light receiving range so that the same scattered light does not enter each of the scattered light detectors;
The scanning light on the concave defect or the convex defect on the detection light is used to compare time waveforms representing changes in scattered light intensity detected by the plurality of scattered light detectors, and the defect type of the flat substrate is a concave defect or An apparatus for inspecting a surface state of a flat substrate, comprising: a waveform comparison / determination unit that determines which of the convex defects is present.   The angle with respect to the substrate normal when the irradiation point is connected to the lower end of the light receiving aperture of the light receiving system that receives the scattered light is determined from the angle with respect to the substrate normal of the specularly reflected light from the irradiation point. The flat substrate surface condition inspection apparatus according to claim 1, wherein the light receiving system is set to have a small angle.   The plurality of scattered light detectors are provided in the light receiving system, and are two scattered light detectors that respectively detect scattered light dispersed by a half mirror that divides the scattered light. Item 2. The flat substrate surface condition inspection apparatus according to Item 1. The surface of the flat substrate placed on the stage is scanned with the detection light irradiated by the light projecting system, and the scattered light from the surface is received while being sent at a predetermined interval in the axial direction perpendicular to the scanning direction. In the surface state inspection apparatus for the flat plate substrate for inspecting whether the defect type on the surface of the flat plate substrate is a concave defect or a convex defect, based on the detected output signal from the light receiving system,
A light projecting system that irradiates an irradiation point with the detection light at a predetermined incident angle with respect to a substrate normal of the flat substrate to the surface of the flat substrate;
A first light receiving system provided in a space opposite to the light projecting system with respect to the substrate normal, and receiving the scattered light;
On the surface side, provided on the irradiation point of the detection light and provided in a second light receiving system for receiving the scattered light and the light receiving system, the scattered light detector of the first light receiving system and the second light receiving system A light receiving range limiting means for limiting the light receiving range so that the same scattered light does not enter the scattered light detector of the light receiving system ;
A change in scattered light intensity detected by the scattered light detector of the first light receiving system and the scattered light detector of the second light receiving system is detected by scanning the detection light on the concave defect or convex defect. An apparatus for inspecting a surface state of a flat plate substrate, comprising: waveform comparison determination means for comparing time waveforms to be expressed and determining whether a surface defect of the flat plate substrate is a concave defect or a convex defect. The angle with respect to the substrate normal when the irradiation point is connected to the lower end of the light receiving aperture of the light receiving system that receives the scattered light is determined from the angle with respect to the substrate normal of the specularly reflected light from the irradiation point. 5. The flat substrate surface condition inspection apparatus according to claim 4, wherein the light receiving system is set to have a small angle. The surface of the flat substrate placed on the stage is scanned with the detection light irradiated by the light projecting system, and the scattered light from the surface is received while being sent at a predetermined interval in the axial direction perpendicular to the scanning direction. In the method for inspecting the surface state of a flat substrate, the flat substrate is inspected whether the defect type on the surface of the flat substrate is a concave defect or a convex defect, based on the detected output signal from the light receiving system. Irradiating an irradiation point with the detection light at a predetermined incident angle with respect to the substrate normal of the flat substrate to the surface of
The substrate method when the irradiation point is provided in a space opposite to the light projecting system with respect to the substrate normal, and the lower end portion of the light receiving port for receiving the scattered light of the light receiving system is connected. Adjusting the angle relative to the substrate normal of the light receiving system so as not to receive specularly reflected light from the irradiation point,
The scattered light detector that detects the scattered light received by the light receiving system is limited to a light receiving range so that the scattered light entering from the light receiving port does not overlap and enter.
By comparing the time waveform representing a change in scattered light intensity detected by the plurality of scattered light detectors by scanning the concave light or the convex defect of the detection light,
A method for inspecting a surface state of a flat substrate, comprising determining whether the surface defect of the flat substrate is a concave defect or a convex defect.   7. The plate substrate surface state inspection method according to claim 6, wherein the scattered light is split into two by a half mirror, and the intensity of each scattered light is detected by two scattered light detectors. The surface of the flat substrate placed on the stage is scanned with the detection light irradiated by the light projecting system, and the scattered light from the surface is received while being sent at a predetermined interval in the axial direction perpendicular to the scanning direction. In the method of inspecting the surface state of the flat substrate, inspecting whether the defect type on the surface of the flat substrate is a concave defect or a convex defect, based on the detected output signal from the light receiving system,
Irradiating the irradiation point with the detection light at a predetermined incident angle with respect to the substrate normal of the flat substrate on the surface of the flat substrate;
Provided in the space opposite to the light projecting system with respect to the substrate normal, and with respect to the substrate normal when the irradiation point and the lower end of the scattered light receiving port of the light receiving system are connected Receiving the scattered light by a first light receiving system whose angle is set so as not to receive specularly reflected light from the irradiation point;
On the surface side, the scattered light is received by a second light receiving system that is provided on the irradiation point of the detection light and receives the scattered light,
A change in scattered light intensity detected by the scattered light detector of the first light receiving system and the scattered light detector of the second light receiving system is detected by scanning the detection light on the concave defect or convex defect. Compare the time waveforms that represent
A method for inspecting a surface state of a flat substrate, comprising determining whether the surface defect of the flat substrate is a concave defect or a convex defect.