JP6940302B2 - Defect inspection equipment and defect inspection method - Google Patents

Description

The present invention relates to a defect inspection apparatus and a defect inspection method, and more particularly to a defect inspection apparatus and a defect inspection method for detecting a defect in a wafer.

In order to improve the yield of semiconductor devices manufactured on wafers such as silicon wafers, wafers are inspected by a defect inspection device in the inspection process.

Japanese Unexamined Patent Publication No. 2009-150910

Defects formed on the wafer are classified according to shape, brightness, etc. in the image obtained by capturing the upper surface of the wafer. However, it may not be possible to distinguish them on the image only by the classification based on the shape and the brightness, even though the cause of the occurrence and the material contained therein are different defects. As described above, it is difficult to classify the defects formed on the wafer by the defect type.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a defect inspection apparatus and a defect inspection method capable of accurately detecting a predetermined defect formed on the upper surface of a wafer. And.

The defect inspection apparatus according to the present invention uses the illumination light including an illumination side polarizer that linearly polarizes the illumination light and light that is linearly polarized in the first direction parallel to the incident surface by the illumination side polarizer. An illumination optical system that illuminates the upper surface, a light receiving side polarizer that transmits the reflected light including the light of the component in the second direction intersecting the first direction in the reflected light reflected by the upper surface, and the above. The receiver includes a receiver that receives the reflected light transmitted through the light receiving side polarizer and detects a defect, and the receiver reflects the illumination light inside the concave crystalline pit defect formed on the upper surface. The reflected light, which is linearly polarized in the first direction contained in the illumination light, is reflected inside the crystalline pit defect, so that the light of the component in the second direction is reflected. The reflected light that comes to include the above is received. With such a configuration, a predetermined defect formed on the upper surface of the wafer can be detected with high accuracy.

Further, the defect inspection method according to the present invention includes the step of linearly polarizing the illumination light by the illumination side polarizer and the illumination including the light linearly polarized in the first direction parallel to the incident surface by the illumination side polarizer. The step of illuminating the upper surface of the wafer with light and the reflected light including the light of the component in the second direction intersecting the first direction in the reflected light reflected on the upper surface are transmitted through the light receiving side polarizer. In the step of detecting the defect, the receiver is formed on the upper surface thereof, comprising a step of receiving the reflected light transmitted through the light receiving side polarizer by the receiver and detecting a defect. The reflected light reflected by the illumination light inside the concave crystalline pit defect, and the light contained in the illumination light linearly polarized in the first direction is inside the crystalline pit defect. By reflecting the light, the reflected light that includes the light of the component in the second direction is received. With such a configuration, a predetermined defect formed on the upper surface of the wafer can be detected with high accuracy.

According to the present invention, it is possible to provide a defect inspection apparatus and a defect inspection method capable of accurately detecting a predetermined defect formed on the upper surface of a wafer.

It is a block diagram which exemplifies the defect inspection apparatus which concerns on embodiment. It is a figure which illustrated the incident light and the reflected light on the upper surface of a wafer in the defect inspection apparatus which concerns on embodiment. It is sectional drawing which illustrates the crystalline pit defect detected by the defect inspection apparatus which concerns on embodiment. It is sectional drawing which illustrates another example of the crystalline pit defect detected by the defect inspection apparatus which concerns on embodiment. It is a flowchart which illustrates the defect inspection method which concerns on embodiment. It is a graph exemplifying the amplitude reflectance of p-polarized light and s-polarized light, the horizontal axis shows the angle of incidence, and the vertical axis shows the amplitude reflectance. It is a graph exemplifying the phase change of p-polarized light and s-polarized light, the horizontal axis shows the incident angle, and the vertical axis shows the phase change. It is a block diagram which exemplifies the case where the crystalline pit defect is not formed on the upper surface of the wafer in the defect inspection apparatus which concerns on embodiment. It is a figure which illustrated the optical path of the incident light and the reflected light in the crystalline pit defect formed on the upper surface of the wafer which concerns on embodiment. It is a graph exemplifying the phase change of p-polarized light and s-polarized light, the horizontal axis shows the incident angle expanded in the range of 75 ° to 80 °, and the vertical axis shows the phase change.

Hereinafter, the specific configuration of the present embodiment will be described with reference to the drawings. The following description shows preferred embodiments of the present invention, and the scope of the present invention is not limited to the following embodiments. In the following description, those having the same reference numerals indicate substantially the same contents.

(Embodiment)
The defect inspection apparatus and the defect inspection method according to the embodiment will be described. The present embodiment is a defect inspection apparatus and a defect inspection method for inspecting a predetermined defect formed on the upper surface of a wafer. First, the defect inspection device will be described.

<Configuration of defect inspection equipment>
FIG. 1 is a configuration diagram illustrating the defect inspection device 1 according to the embodiment. As shown in FIG. 1, the defect inspection device 1 includes a light source 10, an illumination side polarizer 11, a light receiving side polarizer 12, a beam splitter 13, an objective lens 14, and a receiver 15. Further, the defect inspection device 1 may have other optical members (not shown). The light source 10, the beam splitter 13, and the objective lens 14 are referred to as an illumination optical system. The defect inspection device 1 detects, for example, a defect formed on the upper surface 21 of the wafer 20. Note that FIG. 1 shows the configuration of the above-mentioned constituent members in the defect inspection device 1, and does not show the actual positions of the constituent members exactly.

Here, for convenience of explanation of the defect inspection device 1, an XYZ Cartesian coordinate system is introduced. For example, the Z-axis direction is the vertical direction, and the upper direction is the + Z-axis direction. Let the XY plane be the horizontal plane. The inspection surface of the wafer 20 is referred to as the upper surface 21, but it does not mean that the wafer 20 faces upward at the time of inspection, and is merely a convenient name.

The light source 10 produces the illumination light L11. The light source 10 emits the generated illumination light L11. The illumination light L11 emitted from the light source 10 is, for example, white light. The illumination light L11 is not limited to white light, and may include light having a predetermined wavelength. The illumination light L11 emitted from the light source 10 is, for example, unpolarized. An illumination side polarizer 11 and a beam splitter 13 are arranged on the optical axis C1 of the illumination light L11 emitted from the light source 10.

The illumination side polarizer 11 is, for example, a polarizing plate, and polarizes the illumination light L11 emitted from the light source 10. The illumination side polarizer 11 linearly polarizes the illumination light L11 in, for example, the first direction 16 orthogonal to the optical axis C1. As a result, the illumination light L11 includes light linearly polarized in the first direction 16.

The beam splitter 13 reflects a part of the illumination light L11. The beam splitter 13 is, for example, a half mirror. The objective lens 14 and the wafer 20 are arranged on a part of the optical axis C1 of the illumination light L11 reflected by the beam splitter 13.

The objective lens 14 collects the illumination light L11. The objective lens 14 focuses the illumination light L11 on the upper surface 21 of the wafer 20 to be inspected. As a result, the upper surface 21 of the wafer 20 is illuminated by the illumination light L11. The illumination light L11 that illuminates the upper surface 21 of the wafer 20 is also referred to as incident light L10.

FIG. 2 is a diagram illustrating incident light L10 and reflected light R10 on the upper surface 21 of the wafer 20 in the defect inspection device 1 according to the embodiment. As shown in FIG. 2, when the illumination light L11 is incident on the upper surface 21 of the wafer 20 at an incident angle θ, the light contained in the illumination light L11 linearly polarized in the first direction 16 is applied to the incident surface 23. Make it parallel. Light that is linearly polarized parallel to the incident surface 23 in this way is called p-polarized light. Therefore, the illumination light L11 contains p-polarized light. As described above, the illumination optical system illuminates the upper surface 21 of the wafer 20 with the illumination light L11 including p-polarized light linearly polarized in the first direction 16 parallel to the incident surface 23 by the illumination side polarizer 11. The light linearly polarized in the direction orthogonal to the incident surface 23 is called s-polarized light. For example, the light linearly polarized in the second direction 17 intersecting the first direction 16 is s-polarized light.

As shown in FIG. 1, the objective lens 14 collects the reflected light R10 reflected by the illumination light L11 on the upper surface 21 of the wafer 20. As will be described later, the reflected light L10 reflected on the upper surface 21 of the wafer 20 at the portion where the crystalline pit defect is not formed contains a component of light linearly polarized in the first direction 16. The reflected light that is reflected at the portion where the crystalline pit defect is not formed and contains the light component linearly polarized in the first direction 16 is referred to as the reflected light R11.

As will be described later, the reflected light R10 reflected at the portion where the crystalline pit defect is formed on the upper surface 21 of the wafer 20 contains a component of light linearly polarized in the second direction 17 intersecting the first direction 16. Includes. The reflected light that is reflected at the portion where the crystalline pit defect is formed and contains the light component linearly polarized in the second direction 17 is referred to as the reflected light R12. Therefore, the reflected light R10 reflected by the upper surface 21 of the wafer 20 includes the reflected light R11 and the reflected light R12. A beam splitter 13, a light receiving side polarizing element 12, and a light receiving receiver 15 are arranged on the optical axis C1 of the reflected light R10 focused by the objective lens 14.

The beam splitter 13 transmits a part of the reflected light R10. The light receiving side polarizing element 12 transmits the reflected light R12 containing the component of the second direction 17 intersecting the first direction 16 in the reflected light R10 reflected by the illumination light L11 on the upper surface 21 of the wafer 20. That is, the light receiving side polarizer 12 blocks the reflected light R11 including the p-polarized light linearly polarized in the first direction 17. For example, the light receiving side polarizer 12 is arranged in a cross Nicol with respect to the illumination side polarizing element 11 so that the first direction 16 and the second direction 17 are orthogonal to each other.

The light receiver 15 receives the reflected light R12 transmitted through the light receiving side polarizing element 12 and detects a defect. That is, the light receiver 15 receives the reflected light R12 having a light component linearly polarized in the second direction 17 that has passed through the light receiving side polarizer 12. The light receiving surface on which the light receiver 15 receives the reflected light R12 and the upper surface 21 of the wafer 20 on which the objective lens 14 collects the illumination light L11 are confocal positions. Therefore, the receiver 15 receives the reflected light R12 from the vicinity of the focal point of the objective lens 14 on the upper surface 21 of the wafer 20 in a confocal state. The light receiver 15 inspects the defect formed on the upper surface 21 of the wafer 20 by the reflected light R12 reaching the light receiving surface.

<Composition of crystalline pit defects>
Next, the crystalline pit defect detected by the defect inspection device 1 according to the present embodiment will be described. FIG. 3 is a cross-sectional view illustrating the crystalline pit defect 24 detected by the defect inspection device 1 according to the embodiment. As shown in FIG. 3, the crystalline pit defect 24 has a concave shape opened in the upper surface 21 of the wafer 20. The crystalline pit defect 24 is formed on, for example, the upper surface 21 of the wafer 20 having a crystal plane orientation of <100>. The crystalline pit defect 24 is a pyramidal-shaped recess whose diameter is enlarged toward the opening 25 side of the upper surface 21. In FIG. 3, the surface formed on the apex side of the pyramid is the bottom surface 26 of the recess.

The crystal plane orientation of the side surface 27 of the recess is <111>. The angle between the opposing side surfaces 27 in the recess is, for example, 70.6 °. The angle of inclination of the side surface 27 from the horizontal plane is, for example, 54.7 °. The crystal plane orientation <100> on the upper surface 21 and the crystal plane orientation <110> orthogonal to the crystal plane orientation <111> on the side surface 27 are. As described above, the crystalline pit defect 24 is formed on the upper surface 21 of the wafer 20 having a crystal plane orientation of <100>, the side surface 27 having a crystal plane orientation of <111>, and the bottom surface 26 having a crystal plane orientation of <100>. It has a concave shape with.

Such a crystalline pit defect 24 is a typical defect detected by the defect inspection device 1 in the present embodiment, and is a defect targeted by the defect inspection device 1. As shown in FIG. 3, the crystalline pit defect 24 is a side surface 27 having a predetermined crystal plane orientation and having a predetermined angle with respect to the upper surface 21 of the wafer 20. Such crystalline pit defects 24 are easily formed by controlling the mixing ratio of the chemical solution used for etching. For example, the crystalline pit defect 24 is formed by a chemical solution containing an aqueous solution of TMY (trimethyl-2 hydroxyethylammonium hydroxide).

As shown in FIG. 4, the crystalline pit defect 24a may be covered with the film 28. That is, the bottom surface 26 and the side surface 27 of the recess may be covered with the film 28, or the inside of the recess may be filled with the film 28. In that case, the film 28 contains a material that transmits the illumination light L11 and the reflected light R12. As described above, the crystalline pit defect 24a may have a film through which the illumination light L11 and the reflected light R12 are transmitted. Further, the film 28 covering the crystalline pit defect 24a may or may not rotate the polarization plane of the linearly polarized illumination light L11.

<Defect inspection method>
Next, as an operation of the defect inspection apparatus 1 of the present embodiment, a method of inspecting defects formed on the upper surface 21 of the wafer 20 will be described. FIG. 5 is a flowchart illustrating the defect inspection method according to the embodiment. As shown in step S11 of FIG. 5, first, the illumination light L11 is linearly polarized in the first direction 16 by the illumination side polarizer 11. As a result, the illumination light L11 includes light linearly polarized in the first direction 16.

Next, as shown in step S12 of FIG. 5, the upper surface 21 of the wafer 20 is illuminated with the illumination light L11 linearly polarized in the first direction 16. As a result, the illumination light L11 illuminates the portion of the upper surface 21 of the wafer 20 where the crystalline pit defect 24 is not formed and the portion where the crystalline pit defect 24 is formed. The illumination light L11 contains p-polarized light. Hereinafter, the amplitude reflectance and the phase change when the upper surface 21 of the wafer 20 is illuminated with p-polarized light and s-polarized light will be described.

FIG. 6 is a graph illustrating the amplitude reflectance of p-polarized light and s-polarized light, with the horizontal axis indicating the angle of incidence and the vertical axis indicating the amplitude reflectance. The amplitude reflectance is, for example, in the case of reflection on the upper surface 21 of the wafer 20 containing silicon, the wavelength of the illumination light L11 is 504 nm, and the refractive index n and the extinction coefficient k at that time are 4. 277 and 0.066.

As shown in FIG. 6, in the case of s-polarized light, the reflectance is about 0.6 when the incident angle is 10 ° or less, and the larger the incident angle, the larger the reflectance, which approaches 90 °. It's getting closer to 1. On the other hand, in the case of p-polarized light, the reflectance is about 0.6 when the incident angle is 10 ° or less, and the reflectance decreases as the incident angle increases, and becomes 0 at about 75 °. .. This angle is called the Blue Star angle. When it becomes larger than the Blue Star angle, the reflectance increases.

FIG. 7 is a graph illustrating the phase change of p-polarized light and s-polarized light, with the horizontal axis showing the angle of incidence and the vertical axis showing the phase change. As shown in FIG. 7, in the case of s-polarized light, the phase change is negligibly small even if the incident angle changes. On the other hand, in the case of p-polarized light, the phase change is negligibly small when the incident angle is equal to or less than the angle a (near 70 °), but the phase change becomes large when the angle is larger than the angle a. .. Then, the phase change sharply increases when the angle b (around 75 °) or more, and becomes about 180 ° when the angle c (around 80 °) or more.

In the present embodiment, the upper surface 21 of the wafer 20 is illuminated with the illumination light L11 containing p-polarized light. Here, the optical path of the reflected light R11 in which the illumination light L11 is reflected in the portion where the crystalline pit defect 24 is not formed, and the reflected light R12 in which the illumination light L11 is reflected in the portion where the crystalline pit defect 24 is formed. It will be explained separately from the optical path of. First, the reflected light R11 will be described.

<Reflected light R11 reflected in the portion where the crystalline pit defect 24 is not formed>
FIG. 8 is a configuration diagram illustrating the reflected light R11 reflected by the illumination light L11 at the portion of the upper surface 21 of the wafer 20 where the crystalline pit defect 24 is not formed in the defect inspection apparatus 1 according to the embodiment. As shown in FIG. 8, when the crystalline pit defect 24 is not formed on the upper surface 21 of the wafer 20, and the illumination light L11 is incident on the upper surface 21 of the wafer 20 at an incident angle of 70 ° or less. The p-polarized light plane does not rotate when the illumination light L11 is reflected by the upper surface 21. That is, the plane of polarization does not change in the direction along the first direction 16.

Therefore, the reflected light R11 does not have a component in the second direction 17 that intersects the first direction 16. Therefore, the reflected light R11 is blocked by the light receiving side polarizer 12. As described above, since the reflected light R11 does not reach the receiver 15, the image captured by the receiver 15 becomes dark.

<Reflected light R12 reflected at the portion where the crystalline pit defect 24 is formed>
On the other hand, as shown in FIG. 1, when the crystalline pit defect 24 is formed on the upper surface 21 of the wafer 20, the illumination light L11 is incident on the upper surface 21 of the wafer 20 at an incident angle of 70 ° or less. In this case, when the illumination light L11 is reflected by the crystalline pit defect 24 formed on the upper surface 21 of the wafer 20, the polarization plane of p-polarized light rotates. That is, before being reflected by the crystalline pit defect 24, the p-polarized light plane linearly polarized in the first direction 16 is rotated by being reflected by the crystalline pit defect 24. Then, the plane of polarization changes from the first direction 16 and comes to have a component of the second direction 17 intersecting the first direction 16.

Therefore, of the reflected light R10, the reflected light R12 reflected by the crystalline pit defect 24 has a component that is transmitted without being blocked by the light receiving side polarizer 12. Therefore, as shown in step S13 of FIG. 5, the light receiving side polarizing element 12 is transmitted through the component in the second direction 17 in the reflected light R12. As a result, the reflected light R12 reflected by the crystalline pit defect 24 reaches the receiver 15. Therefore, the receiver 15 is the reflected light R12 reflected by the illumination light L11 inside the concave crystalline pit defect 24 formed on the upper surface 21 of the wafer 20, and is included in the illumination light L11 in the first direction 16. The linearly polarized light is reflected inside the crystalline pit defect 24 to receive the reflected light R12 that contains the light of the component in the second direction 17. In this way, as shown in step S14 of FIG. 5, the light receiver 15 receives the reflected light R12 that has passed through the light receiving side polarizing element 12 and detects a defect.

<Principle of observing the image of crystalline pit defect 24>
In the following, the principle of observing the image of the crystalline pit defect 24 will be described as an example.
As described above, when the crystalline pit defect 24 is formed on the upper surface 21 of the wafer 20, the complex amplitude reflectance and the phase of the p-polarized light component of the reflected light R12 are different from those of the illumination light L11. From this, it is considered that the incident angle of p-polarized light with respect to the crystalline pit defect 24 is an incident angle that changes the complex amplitude reflectance and the phase of the p-polarized light component. As a result, the reflected light R12 to which the illumination light L11 is reflected by the crystalline pit defect 24 has a polarization plane different from that of the illumination light L11.

FIG. 9 is a diagram illustrating an optical path of the illumination light L11 in the crystalline pit defect 24 formed on the upper surface 21 of the wafer 20 according to the embodiment. For example, the numerical aperture NA indicates the optical path of the illumination light L11 and the reflected light R12 for the crystalline pit defect 24 when the maximum angle of the incident light with respect to the optical axis is 26.7 °.

As shown in FIG. 9, the illumination light L11 incident on the crystalline pit defect 24 is reflected on one side surface 27a of the recess. The reflected light R12 reflected on the side surface 27a is reflected on the bottom surface 26 and reflected on the side surface 27b facing the side surface 27a. After being reflected on the side surface 27b, the reflected light R12 is focused by the objective lens 14. The optical path of the illumination light L11 in the crystalline pit defect 24 shown in FIG. 9 is an example, and the optical path of the illumination light L11 in the crystalline pit defect 24 is not limited to the optical path shown in FIG. It is possible that an image of the crystalline pit defect 24 is observed by the principle of traveling in another optical path.

The illumination light L11 incident on the crystalline pit defect 24 is reflected twice on the side surface 27 before being reflected from the crystalline pit defect 24. That is, it is reflected on the side surfaces 27a and 27b. The illumination light L11 is incident on the side surface 27a at an incident angle θ1 larger than 70 °. The reflected light R12 is incident on the side surface 27b at an incident angle θ2 larger than 70 °. Therefore, the reflected light R12 reflected by the crystalline pit defect 24 is reflected twice by the side surface 27a and the side surface 27b at an incident angle larger than 70 °.

Further, the shape of the crystalline pit defect 24 is, for example, symmetrical with respect to an axis orthogonal to the center of the bottom surface 26. Therefore, the incident angles are the same on the side surface 27a and the side surface 27b.

FIG. 10 is a graph illustrating the phase change of p-polarized light and s-polarized light. The horizontal axis shows the enlarged range of 70 ° to 80 ° at the incident angle, and the vertical axis shows the phase change. The phase change when reflected at an incident angle of around 76 ° is 45 °. The phase change when reflected at an incident angle of around 77 ° is 135 °. Therefore, the phase change when reflected twice near the incident angle of 76 ° and the phase change when reflected twice near the incident angle of 77 ° are 90 °. In this case, the component of the reflected light R12 in the second direction 17 becomes the largest. Therefore, the crystalline pit defect 24 can be detected accurately by the light receiver 15 by injecting the illumination light L11 under such a condition. The relationship between the incident angle and the phase change in FIG. 10 is an example, and the relationship between the incident angle and the transition change is not limited to the relationship shown in FIG.

The region 29 in the numerical aperture shown in FIG. 9 includes illumination light L11 having various incident angles. Further, the region 29 includes reflected light R12 having various reflection angles. Therefore, the region 29 includes the reflected light R12 having a phase change in which the component in the second direction 17 in the reflected light R12 is the largest. Therefore, by incident the illumination light L11 linearly polarized in the first direction 16 into the crystalline pit defect 24, the crystalline pit defect can be easily and accurately detected.

Next, the effect of this embodiment will be described.
The defect inspection device 1 of the present embodiment inspects the crystalline pit defect 24 formed on the upper surface 21 of the wafer 20 by using the illumination light L11 linearly polarized in the first direction 16 by the illumination side polarizer 11. ing. The reflected light R12 reflected by the crystalline pit defect 24 has a component in the second direction 17 that intersects the first direction 16. Therefore, the crystalline pit defect 24 can be inspected by transmitting and detecting only the reflected light R12 through the polarizing element 12 on the light receiving side. In this way, the defect inspection device 1 can accurately detect a predetermined defect formed on the upper surface 21 of the wafer 20, for example, a crystalline pit defect 24.

Due to the characteristic shape as described above, the crystalline pit defect 24 becomes a reflected light R12 having a component in the second direction 17 when illuminated with an illumination light L11 including light linearly polarized in the first direction 16. Rotate the plane of polarization. Therefore, in the image obtained by capturing the upper surface 21 of the wafer 20, the crystalline pit defect 24, which could not be distinguished only by the classification by shape and brightness, is selected by using the defect inspection device 1 of the present embodiment. Can be distinguished.

The range of the incident angle that causes a phase change in the linearly polarized illumination light L11 is a narrow range of 75 ° or more. Therefore, the phase change does not occur in the mere recess formed on the upper surface 21 of the wafer 20, and the phase change is remarkably caused in the case of the crystalline pit defect 24. Therefore, the crystalline pit defect 24 can be detected with high accuracy.

Although the embodiments of the present invention have been described above, the present invention includes appropriate modifications that do not impair its purpose and advantages, and is not limited by the above embodiments.

1 Defect inspection device 10 Light source 11 Light source 11 Polarizer 12 Light receiver 13 Beam splitter 14 Objective lens 15 Receiver 16 First direction 17 Second direction 20 Wafer 21 Top surface 22 Defect 23 Incident surface 24, 24a Crystalline pit defect 25 Opening 26 Bottom surface 27, 27a, 27b Side surface 28 Film 29 Region C1 Optical axis L10 Incident light L11 Illumination light R10, R11, R12 Reflected light

Claims (9)

An illumination side polarizer that linearly polarizes the illumination light,
An illumination optical system that illuminates the upper surface of the wafer with the illumination light including light linearly polarized in the first direction parallel to the incident surface by the illumination side polarizer.
A light receiving side polarizing element that transmits the reflected light including the light of the component in the second direction intersecting the first direction in the reflected light reflected by the illumination light on the upper surface.
A receiver that detects defects by receiving the reflected light that has passed through the polarizing element on the light receiving side.
With
The receiver is
The reflected light in which the illumination light is reflected inside the concave crystalline pit defect formed on the upper surface, and the light contained in the illumination light that is linearly polarized in the first direction is the crystalline light. By reflecting the light inside the pit defect, the reflected light that includes the light of the component in the second direction is received .
The crystalline pit defect is a concave shape having a side surface having a crystal plane orientation of <100> and a side surface having a crystal plane orientation of <111> and a bottom surface having a crystal plane orientation of <100>. can be,
The illumination light is incident on the side surface at an incident angle larger than 70 °.
Defect inspection equipment. The light receiving side polarizer is arranged in a cross Nicol with respect to the illumination side polarizing element so that the first direction and the second direction are orthogonal to each other.
The defect inspection apparatus according to claim 1. The illumination optical system further includes an objective lens.
The receiver confocally receives the reflected light from the vicinity of the focal point of the objective lens on the upper surface.
The defect inspection apparatus according to claim 1 or 2. In the crystalline pit defect, a film that transmits the illumination light and the reflected light is formed inside the crystallized pit defect.
The defect inspection apparatus according to any one of claims 1 to 3. The process of linearly polarized the illumination light with the illuminator on the illumination side,
A step of illuminating the upper surface of the wafer with the illumination light including light linearly polarized in the first direction parallel to the incident surface by the illumination side polarizer.
A step of transmitting the light receiving side polarizer with respect to the reflected light including the light of the component in the second direction intersecting the first direction in the reflected light reflected by the illumination light on the upper surface.
A step of detecting a defect by receiving the reflected light transmitted through the polarizing element on the light receiving side with a light receiver.
With
In the step of detecting the defect, the receiver is
The reflected light in which the illumination light is reflected inside the concave crystalline pit defect formed on the upper surface, and the light contained in the illumination light that is linearly polarized in the first direction is the crystalline light. By reflecting the light inside the pit defect, the reflected light that contains the light of the component in the second direction is received .
The crystalline pit defect is a concave shape having a side surface having a crystal plane orientation of <100> and a side surface having a crystal plane orientation of <111> and a bottom surface having a crystal plane orientation of <100>. can be,
The illumination light is incident on the side surface at an incident angle larger than 70 °.
Defect inspection method. The light receiving side polarizer is arranged in a cross Nicol with respect to the illumination side polarizing element so that the first direction and the second direction are orthogonal to each other.
The defect inspection method according to claim 5. With an additional objective lens
The light receiver is confocally received with the reflected light from the vicinity of the focal point of the objective lens on the upper surface.
The defect inspection method according to claim 5 or 6. In the crystalline pit defect, a film that transmits the illumination light and the reflected light is formed inside the crystallized pit defect.
The defect inspection method according to any one of claims 5 to 7. The crystalline pit defect is formed by a chemical solution containing an aqueous solution of TMY (trimethyl-2 hydroxyethylammonium hydroxide).
The defect inspection method according to any one of claims 5 to 8.

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