JP3186695B2 - Device for detecting defects in semiconductors, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for illuminating an internal defect of a test object such as a semiconductor wafer using a laser beam or the like, and observing the scattered light thereof for detection.

[0002]

2. Description of the Related Art FIG. 4 of the conventionally known Japanese Patent Application Laid-Open No. Hei 4-24541 shows that the depth of a laser beam incident on a test object made of gallium arsenide by appropriately selecting the wavelength of the laser beam to be incident. When the internal defect of the test object made of gallium arsenide is measured due to such characteristics, for example, when a laser beam having a wavelength of about 900 nm is used, the surface of the test object can be measured. It is described that a laser beam incident from the front side can be sufficiently attenuated near the back surface (see line 13 in the upper right column of the sixth sheet to line 11 of the lower left column in the sixth sheet). Also, JP-A-2-16438, JP-A-4-9586
No. 1, Japanese Unexamined Patent Application Publication No. 2-190974, Japanese Unexamined Patent Application Publication No.
-106444, JP-A-63-212911, JP-A-3-238348, and JP-A-4-234.
Japanese Patent Publication No. 26845 also describes a technique substantially similar to that of the above publication.

[0003]

The technique described in the above-mentioned publication is a technique for controlling the depth at which a laser beam is incident on a test object by appropriately selecting the wavelength of the laser beam to be incident. According to this technique, however, as shown in FIG. 4 of JP-A-4-24541, the absorption coefficient k of gallium arsenide hardly changes until near the wavelength of 870 nm, and sharply decreases to 900 nm exceeding 870 nm. I do. Therefore, it is not possible to observe a defect very close to the surface of the test object, for example, near 1 μm by distinguishing the defect from the surface defect only by selecting the wavelength. In order to detect defects near the surface of the test object near the surface of the test object separately from the defects on the surface of the test object, instead of applying the absorption characteristics of the incident laser beam, the surface defects of the laser beam and the internal defects What is necessary is just to apply the change characteristic of the scattering intensity from a defect.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present application provides a multi-layer semiconductor substrate in which a predetermined laser beam is made incident, optical information generated from the multi-layer semiconductor substrate is obtained by an observation optical system, and the obtained optical information is added to the obtained optical information. In detecting a surface defect and an internal defect of a multilayer semiconductor substrate based on the wavelength, a wavelength (λ2) at which a large reflectance is generated by interference of reflected light on the surface and the interface.
, Λ4,...) And small wavelengths (λ1, λ3
,…)), Wavelengths with large reflectance (λ2, λ4, ...)
Scattered image from dust or scratches on the surface of the multi-layer semiconductor substrate is detected using any one of the above, and wavelengths with small reflectance (λ1,
λ3,…)) is a device that can distinguish between surface defects and internal defects by detecting scattered images from defects inside the multi-layer semiconductor substrate using any one of them and comparing these two scattered images. A test object 105 made of a semiconductor or the like, a laser device 103 capable of making a predetermined laser beam 101 incident on the test object 105, and the laser beam 10
A condenser lens 107 for focusing and irradiating the object 1 on the test object 105; a microscope 109 for receiving scattered light from the test object 105 by the converged laser beam and enlarging a scattered image thereof; projection means 113 for projecting an image an imaging element 111 for obtaining the image signals of the scattered image by photoelectrically converting the pattern to be used to focus the microscope 109 with respect to the object to be inspected 105 on the object to be detected 105 And a stage 115 for moving the test object 105 by driving means.
Is a spatial modulation element pattern 121, a light source 123, and the light emitted from the light source 123.
Lens 125, a diffusion plate 127, a convex lens 129, and a light projecting lens 131 and a half mirror 133 for forming an image of the spatial modulation element pattern 121 illuminated by the convex lens 125, the focal point of the microscope 109, and the like. This is a device for detecting a defect in a semiconductor or the like.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus capable of implementing the method for detecting an internal defect in a semiconductor or the like according to the present invention will be described .
103 is a laser device, the more the laser device 103
The laser beam 101 is irradiated on the surface of the wafer and the surface of the SiO ₂ layer.
Due to the interference of the reflected light, it increases according to the wavelength λ of the laser light
Wavelength caused the reflectance (λ2, λ4, ...) and a small the reflectivity
Λ1, λ3,...
Is, a condenser lens 107 for irradiating by focusing the laser beam 101 to the test object 105, a laser beam 101
Microscope 109 for receiving scattered light from the test object 105 caused by the light and enlarging the scattered image, and an imaging device 1 for photoelectrically converting the enlarged scattered image to obtain an image signal of the scattered image
11, projecting means 113 for projecting a pattern used for focusing the microscope 109 on the test object 105 onto the test object 105, and a normal 1
Between the vertical line 06 and the optical axis 108 of the microscope 109
Is held at 5 to 35 degrees, and the stage 115 is moved by driving means (not shown).

[0006] The microscope 109 is connected to the objective lens 1.
17 and an imaging lens 119. The projection means 113 is illuminated by the spatial modulation element pattern 121, the light source 123, the convex lens 125 for irradiating the light emitted from the light source 123 to the spatial modulation element pattern 121, the diffusion plate 127 and the convex lens 129, and A light projection lens 131 and a half mirror 133 for forming an image of the spatial modulation element pattern 121 at the focal position of the microscope 109 are provided. The spatial modulation element pattern 121 is disposed on the focal plane of the half mirror 133. The object to be inspected 1
05 is inclined.

FIG. 14 shows a case where the test object 105 is a wafer having a fine structure on the surface. The fine structure portion is formed assuming that a layer having an equivalent thickness exists. Then, each part defect and surface defect can be observed. However, in this case, in order to prevent the diffracted light due to the fine structure from entering the observation optical system and making it impossible to observe the internal defect 505, the diffracted light 1 is introduced into the observation optical system.
A filter (mask) 181 for blocking 83 is provided. 185 is specularly reflected light.

FIGS. 15 to 17 are schematic diagrams each showing a configuration of a defect detection apparatus according to still another embodiment of the present invention. These apparatuses detect defects inside and on the surface of the test object 105 using laser light having a wavelength of 400 to 2,000 nm, and detect surface defects using laser light having a wavelength of 200 to 650 nm.

In the apparatus shown in FIG.
Numeral 01 is enlarged in beam diameter by a concave lens 163, is converted into parallel light by a collimator lens 161 and is introduced into an optical path of an observation system via a half mirror 171 (same as 133). Irradiated. Then, as described above, the laser beam 10
1 specular reflection image of surface defect and normal / inverse of internal defect by changing wavelength
The projection image is obtained as an electric signal via the objective lens 117, the imaging lens 119, and the imaging element 111.

In the apparatus shown in FIG. 16, a test object 105 is illuminated by using a laser beam 101 obtained by mixing laser beams having wavelengths λ 1 and λ 2 via a half mirror 169.
The specularly reflected light is divided into a wavelength λ1 component and a wavelength λ2 component by a dichroic mirror-173, and the surface of the test object 105 is observed by the wavelength λ1 component through the imaging lens 119 and the image pickup device 111, and the wavelength λ2 component is used. The specular reflection image from the inside of the test object 105 is formed into an imaging lens 165
Then, observation is performed through the image sensor 167.

In the apparatus shown in FIG.
01 is blocked by the mask 175, and only the light beam in the peripheral portion is reflected by the mirror 177 and the objective lens 11.
The target object 105 is irradiated through the peripheral portion of the object 7 and a specular reflection image is obtained through a central portion of the objective lens 117. Others are the same as the case of FIG.

[0012]

[Action] Next, the action of the observation will be described. FIG. 2 is a principle diagram illustrating the principle of observation of the test object 105 by the apparatus of FIG. In the figure, reference numeral 201 denotes a TV camera including the image sensor 111 and the imaging lens 119 shown in FIG. 1, and the TV camera 201 and the objective lens 117 constitute an observation system. Test object 1
The surface normal line (line parallel to the surface) 106, the optical axis 108 of the observation system, and the optical axis 110 of the laser beam 101 are:
The angle β formed between the object 105 and the optical axis 110 of the laser beam 101 from above one side is 10 to 60 ° when viewed from above, and the laser beam 101 is The optical axis 102 of the bending light 104 of the laser beam 101 refracted in the object 105 and the object 10
The angle α between the normal line 5 and the vertical line is set to be approximately 16 °. When the refracted light 104 is observed by the TV camera 201 inclined to the other side by the angle θ, the field of view 203 is, as shown in the drawing of FIG. 2, the layers 1b, 2b, 3b, 4b of the test object 105. Observation can be made by dividing into measurement areas 1a, 2a, 3a, and 4a corresponding to the depth of each layer.

Referring back to FIG. 1 in this state, first, the light source 123 is turned on, and the convex lens 125 and the diffusion plate 1 are turned on.
The light is irradiated onto the spatial modulation element pattern 121 via the convex lens 27 and the convex lens 129, and an image of the focusing pattern 121 is projected on the test object 105. Next, the stage 1 is adjusted so that the contrast of the projected image of the spatial modulation element pattern 121 is maximized between the measurement areas 2a and 3a.
15 is controlled. Next, this focal position is determined by the layers 2b and 3b.
Stage 115 so as to correspond to the depth position of the boundary between
Is vertically moved a predetermined distance. Next, the laser device 103
The focal point 205 (FIG. 2) of the laser beam 101 from
Measurement areas 1a, 2a, 3a, which are desired detection target layers, and
The position of the laser beam 101 to correspond to
Adjust . Thereby, the measurement regions 1a to 4 in the visual field 203
a corresponds to the layers 1b to 4b, and therefore, if the depth of focus of the observation system covers the layers 1b to 4b of the test object 105, an image of a defect or the like in the visual field 203 indicates the layer in which it exists. It will be obtained with the information. In addition,
In this case, the depth of field is, for example, 20 magnifications of the observation system.
The magnification is about 40 μm, and the magnification is about 15 μm.
Further, the projection of the spatial modulation element pattern 121 is stopped when it becomes unnecessary so as not to hinder observation. This is not the case when a pattern having no pattern that hinders observation is used as the spatial modulation element pattern 121.

In order to perform detection in a range beyond the field of view 203, the laser beam 101 is reciprocated in a direction perpendicular to the maximum tilt direction of the test object 105, and the test object 105 is moved in the maximum tilt direction. By moving the object 105 in parallel to the direction, as shown in FIG.
For example, the scattered image of a defect in a three-dimensional region of about 200 × 200 × 16 μm shows any one of the measurement areas 1a to 4a.
At the same time as the information on the depth position that was detected.

FIG. 4 is an explanatory diagram for explaining the resolution in this detection. As shown in the drawing, the resolution in the surface direction of the test object 105 defined by the interval between each scanning line in the scanning by the laser beam 101 is about 0.4.
Assuming that the refraction angle α of the laser beam 101 in the test object 105 is about 16 °, the resolution in the depth direction is about 1.
4 μm. The resolution in the depth direction can be improved to about 1 μm by improving the resolution in the surface direction.

FIG. 5 is a schematic diagram showing a defect detection method according to another embodiment of the present invention. Here, as a laser device,
A dye laser, a Tit sapphire laser, or the like, which is a wavelength tunable laser, is used. The laser beam 101 emitted from the laser is expanded via a collimator 301 and is irradiated on a test object 105. In this case, it is not necessary to divide the measurement area in the field of view of the TV camera 201. The direction of the normal to the surface of the test object 105 is made to coincide with the direction of the optical axis of the TV camera 201.
Otherwise, the configuration is the same as in FIG.

FIG. 6 is used as a test object 105. SOI (Silicon on Insulat) with multilayer structure of Si crystal
or) is a cross-sectional view of a structured wafer. This wafer is Si substrate 4
01, a 0.2 μm thick oxide film (SiO 2
₂ ) layer 403 and a 1 μm thick layer formed thereon
It has a Si layer 405.

In this configuration, to detect a defect,
The observation system is focused on the surface of the wafer in the same manner as described above. However, here, the Si layer 405 within the depth of focus is used.
Further, since an attempt is made to detect a defect localized in the SiO ₂ layer 403, there is no need to further adjust the focal position. And
The irradiation area of the laser beam 101 is set to the TV camera 20.
Irradiation is performed so as to coincide with the field of view 1 and observation is performed.

FIG. 7 is an explanatory view showing a state when the laser beam 101 is irradiated on the wafer. FIG. 7A shows a case where the reflectance on the wafer surface is large, and FIG. 7B shows a case where the reflectance is small. 7 (a) and FIG.
The graph on the left side of FIG.
4 is a graph showing a change in light intensity 1 of refracted light with respect to a wafer depth D due to No. 1; Note that a curve 509 is an attenuation curve due to absorption.

As shown in FIG. 7, a laser beam 101
Separates the reflected light 501 and the refracted light 503 from the wafer surface (Si crystal having a refractive index of about 3.5) and the SiO ₂ layer 403.
(Refractive index: approximately 1.5) Due to the interference of the reflected light on the surface, the reflectivity R on the surface of the wafer is more dependent on the wavelength λ of the laser light than in the case of the wafer containing only the Si crystal as shown in FIG. It fluctuates in a large range. When the reflectance is large ( λ2, λ
4,...) , As shown in FIG.
When the intensity of the scattered light 507 from the defect 505 at the boundary with the SiO ₂ layer 403 is low and the reflectance is low ( λ1, λ
3,...) Increase on the contrary, as shown in FIG.

Therefore, wavelengths λ 1, λ 3
, Layers 405 ... with a laser beam 101 or one of a, effectively detect scattered images from the interior of the defect layer 403, high wavelength λ2 reflectance, .lambda.4, ... any one of The laser beam is mainly used to detect a scattered image from dust and scratches on the wafer surface. Then, by comparing these scattered images, surface defects and internal defects are clearly distinguished. In addition, as shown in FIG. 8, the vertical oscillation of the reflection intensity due to the interference is observed at a wavelength of 400 nm or more. Therefore, a wavelength of 400 to 200 is provided inside the layer.
Since the light having a wavelength of 0 nm is sufficiently incident, the internal defect is observed using a laser beam in this wavelength range. On the other hand, the light having a wavelength of less than 400 nm does not enter the inside of the layer.
Surface defects may be observed using laser light of m or ordinary light, and internal defects and surface defects may be distinguished.

Note that, instead of changing the wavelength of the laser beam, as shown in FIG.
At the wavelength λ / 2 (=
400-1300 nm) and a wavelength λ (= 800-
(2600 nm) second harmonic generation element 805, which is incident on the wafer, and scattered light from its surface defect and internal defect is used as a fundamental wave and a second harmonic scattered light, respectively, using another observation system. You may make it image.

FIG. 10 shows an example of the scattered image thus obtained. However, as for the wafer as the test object 105, the thickness of the Si layer 405 is 1 μm, and the thickness of the SiO ₂ layer 403 is 0.4 to 0.5 μm, and as shown in FIG.
Half of the surface is the surface 11 as it is, but the other half is the surface 1 where the pits 13 of the internal defect are exposed by etching.
4 is used. FIG. 10A shows a wavelength of 940 n.
500 μm in which an internal scattered image due to the laser light of m
FIG. 10 (b) shows the appearance of a field of view of m squares, and FIG.
The view of the field of view of the same portion where the surface scattered image by the laser light of nm is remarkably appeared is shown. Portion 11a corresponds to surface 11, and portion 14a corresponds to surface 14. In FIG. 10B, dust images on the surface 11 appear at the portion 11a, and countless minute pit images on the surface 11 appear at the portion 14a. Portions 11a and 14 of FIG.
In (a), no fine pit image appears, and numerous dusts, scratches and internal defects on the surface appear countlessly.

FIG. 12 is a graph showing changes in the reflectance R and the scattering intensity S with respect to the wavelength λ of the incident light on the wafer. In the figure, a curve 151 indicates a change in reflectance R by calculation, a curve 153 indicates a change in reflectance R by actual measurement, and a curve 1
Numeral 55 indicates a change in the scattering intensity S from the surface defect by actual measurement, and a curve 157 indicates a change in the scattering intensity S from the internal defect by actual measurement. Now, the reflectance R by actual measurement of this graph
Looking at the change curve 153, the maximum value A of the reflectance R is around 1000 nm, and the minimum value B of the reflectance R is 9 nm.
Since the wavelength is around 40 nm, when a laser beam with a wavelength of 1000 nm is used, only surface defects are detected without being affected by the inside, and when a laser beam with a wavelength of 940 nm is used, only internal defects are detected without being affected by the surface. You. Therefore, a defect near the surface layer of the test object 105 and a defect on the surface of the test object 105, which is impossible in the known example, can be detected separately.

FIGS. 13A and 13B show another test object 10.
5 the same place, the wavelength 1000n reaching inside
The state of a visual field of 500 μm square when observed with a laser beam of m and a laser beam of a wavelength of 451 nm is shown. By comparing the two, a scattered image from an internal defect can be recognized.

As shown in FIG. 14, when the object to be inspected 105 is a wafer having a fine structure on the surface, a layer having a thickness equivalent to the fine structure exists in a portion where the fine structure exists. As a matter of fact, each part defect and surface defect can be observed in the same manner. However, in this case,
A filter (mask) 181 for blocking the diffracted light 183 is provided in the observation optical system in order to prevent the diffracted light due to the fine structure from entering the observation optical system and obstructing the observation of the internal defect 505. The specularly reflected light 185 does not cause any problem.

FIGS. 15 to 17 are schematic diagrams each showing a configuration of a defect detection apparatus according to still another embodiment of the present invention. These apparatuses detect defects inside and on the surface of the test object 105 using laser light having a wavelength of 400 to 2,000 nm, and detect surface defects using laser light having a wavelength of 200 to 650 nm.

In the apparatus shown in FIG.
The beam system is enlarged by the concave lens 163 of the first optical system, converted into parallel light by the collimator lens 161, introduced into the optical path of the observation system via the half mirror 171, and irradiated on the object 105 via the objective lens 117. The specular reflection image of the surface defect and the specular reflection image of the internal defect are changed by changing the wavelength of the laser beam 101 as described above.
17, via the imaging lens 119 and the imaging element 111,
It is obtained as an electric signal.

In the apparatus shown in FIG. 16, the wavelengths λ1 and λ2
The object 105 is illuminated by using the laser beam 101 obtained by mixing the laser beams of the laser light through the half mirror 169, and the specularly reflected light is illuminated by the dichroic mirror-173 to the wavelength λ1.
Component and a .lambda.2 component, and the surface of the test object 105 is divided into the imaging lens 119 and the
At the same time, the specular reflection image from the inside of the test object 105 is observed through the imaging lens 165 and the image sensor 167 by the wavelength λ2 component.

In the apparatus shown in FIG.
01 is blocked by the mask 175, and only the light beam in the peripheral portion is reflected by the mirror 177 and the objective lens 11.
The target object 105 is irradiated through the peripheral portion of the object 7 and a specular reflection image is obtained through a central portion of the objective lens 117. Others are the same as the case of FIG.

[0031]

According to the present invention, a predetermined laser beam is incident on a multi-layer semiconductor substrate, optical information generated from the multi-layer semiconductor substrate is obtained by an observation optical system, and the multi-layer semiconductor substrate is obtained based on the obtained optical information. In detecting surface defects and internal defects, there are two wavelengths (λ2, λ4,...) That produce a large reflectance due to interference of reflected light at the surface and the interface, and wavelengths (λ1, λ3,. , A scattered image from dust or scratches on the surface of the multilayer semiconductor substrate is detected by using one of the wavelengths having large reflectance (λ2, λ4,...), And the wavelength having small reflectance (λ1, λ3,. A device capable of distinguishing a surface defect from an internal defect by detecting a scattered image from a defect inside the multilayer semiconductor substrate by using any one of them and comparing these two scattered images. A test object 105 consisting of A laser device 103 capable of causing a predetermined laser beam 101 to be incident on an inspection object 105;
A condenser lens 107 for focusing and irradiating the laser beam onto a microscope 5; a microscope 109 for receiving scattered light from the test object 105 due to the focused laser beam and enlarging the scattered image; an imaging element 111 for obtaining the image signals of the scattered image, a projection unit 113 for projecting a pattern used to focus the microscope 109 <br/> on the test object 105 with respect to the object to be detected 105, Stage 11 for moving the object to be inspected 105 by driving means
5, the projection means 113 includes a spatial modulation element pattern 121, a light source 123, and a convex lens 1 for irradiating the spatial modulation element pattern 121 with light emitted from the light source 123.
25, a diffusion plate 127, a convex lens 129, and a defect in a semiconductor or the like provided with a light projection lens 131 and a half mirror 133 for forming an image of the spatial modulation element pattern 121 illuminated thereby at a focal position of the microscope 109. , The light source 123 is turned on, the spatial modulation element pattern 121 is irradiated through the convex lens 125, the diffusion plate 127 and the convex lens 129, and the image of the focusing pattern 121 is
5 and then the stage 115 is controlled so that the contrast of the projected image of the spatial modulation element pattern 121 is maximized between the measurement areas 2a and 3a, and the focal position is set between the layers 2b and 3b. The stage 115 is vertically moved by a predetermined distance so as to correspond to the depth position of the boundary, and the focal point 20 of the laser beam 101 from the laser device 103 is moved.
5 is a measurement area 1a, 2a, 3 which is a desired detection target layer.
The position of the laser beam 101 is adjusted so as to correspond to a and 4a so that the measurement areas 1a to 4a in the field of view 203 correspond to the layers 1b to 4b. Therefore, if the depth of focus of the observation system is such that it covers each layer 1b-4b of the test object 105, an image of a defect or the like in the visual field 203 can be obtained together with information on the layer where the defect exists.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of a defect detection device.

FIG. 2 is a principle diagram for explaining the observation principle of the first embodiment.

FIG. 3 is an explanatory diagram in which a test object is scanned in a raster scan.

FIG. 4 is an explanatory diagram of resolution.

FIG. 5 is a schematic diagram of a defect detection method according to another embodiment.

FIG. 6 is a sectional view of a wafer having a multilayer structure.

FIG. 7 is an explanatory diagram when a laser beam is applied to a wafer having a multilayer structure.

FIG. 8 is a graph showing the reflectance on the surface and inside of the wafer.

FIG. 9 is an explanatory diagram of a laser beam including a fundamental wave and a second harmonic.

FIG. 10 is a schematic view of the wafer obtained from FIG. 9;

FIG. 11 is a perspective view of FIG. 10;

FIG. 12 is a graph showing details of the graph in FIG. 8;

FIG. 13 is a state diagram of a scattered image of an internal defect.

FIG. 14 is a second embodiment diagram for explaining the observation principle.

FIG. 15 is a third embodiment diagram for explaining the observation principle.

FIG. 16 is a view of a fourth embodiment illustrating the observation principle.

FIG. 17 is a diagram of a fifth embodiment illustrating the observation principle.

[Explanation of symbols]

101: irradiation laser beam, 102: optical axis of refracted light, 103
... laser device, 104 ... refracted light, 105 ... test object, 1
06: normal line of the test object, 107: condenser lens, 108 ...
Observation optical axis, 109: microscope, 110: incident optical axis, 111
... Imaging element, 113 ... Projection means, 115 ... Stage, 1
Reference numeral 17: Objective lens, 119: Image forming lens, 121: Spatial modulation element pattern, 123: Light source, 125: Convex lens,
127: diffusion plate, 129: convex lens, 131: light projecting lens, 133: half mirror, 151: curve, 153 ...
Curve, 155 ... Curve, 161 ... Collimator lens, 16
3: concave lens, 165: imaging lens, 167: imaging element, 169: half mirror, 171: half mirror, 1
73: dichroic mirror, 175: mask, 177
.., Mirror, 181, filter (mask), 183, diffracted light, 185, specularly reflected light, 203, visual field, 205, focal point, 401, Si substrate, 403, oxide film (SiO ₂ ) layer, 4
05: Si layer, 501: reflected light, 503: refracted light, 505
... Defects, 507 ... Scattered light, 509 ... Curve, 801 ... Laser light, 803 ... Second harmonic generation element, 805 ... Second harmonic generation element, 1a, 2a, 3a, 4a ... Measurement area, R ...
Reflectance, S: scattering intensity.

Claims (1)

(57) [Claims] 1. A predetermined laser beam is made incident on a multilayer semiconductor substrate, optical information generated from the multilayer semiconductor substrate is obtained by an observation optical system, and surface defects and surface defects of the multilayer semiconductor substrate are determined based on the obtained optical information. In detecting an internal defect, of the wavelengths (λ2, λ4,...) At which a large reflectance is generated due to interference of the reflected light at the surface and the interface and the wavelengths (λ1, λ3,. Using one of the large wavelengths (λ2, λ4,...), A scattered image from dust or scratches on the surface of the multilayer semiconductor substrate is detected, and one of the wavelengths with a small reflectance (λ1, λ3,. Is a device capable of distinguishing a surface defect from an internal defect by detecting a scattered image from a defect inside the multi-layer semiconductor substrate by using the device, and comparing the two scattered images , and detecting a test object composed of a semiconductor or the like. The object 105 and the test object 10 A laser device 103 for allowing a predetermined laser beam 101 to be incident on the object, a condensing lens 107 for converging and irradiating the laser beam 101 to the object to be measured 105, and an object to be measured 105 by the focused laser beam Microscope 109 for receiving scattered light from the camera and enlarging the scattered image, and an imaging device 1 for photoelectrically converting the scattered image to obtain an image signal of the scattered image
11 and the microscope 109 with respect to the test object 105.
Test object 10 a pattern used to focus the
5. Projection means 113 for projecting onto the object 5 and the test object 105
And a stage 115 moved by a driving means,
The projection means 113 includes a spatial modulation element pattern 121.
A light source 123, a convex lens 125 for irradiating the light emitted from the light source 123 to the spatial modulation element pattern 121, a diffusion plate 127 and a convex lens 129, and the spatial modulation element pattern 121 illuminated by the convex lens 125 and the convex lens 129. Light projection lens 13 for forming an image
An apparatus for detecting a defect in a semiconductor or the like, comprising: