TWI629467B - Wafer inspection method and wafer inspection device - Google Patents

Abstract

The invention provides a wafer inspection method capable of inspecting the presence or absence of fog spots on a wafer surface. The wafer inspection method of the present invention includes a first step S10 of detecting a spot-shaped defect on a peripheral portion of the surface of the wafer 1 using the first optical system 10 including the ring-shaped optical fiber illumination 11 and the first light receiving unit 12. D; second step S20, using the second optical system 20 including the laser light source 21 and the second light receiving unit 22 and having a lower detection sensitivity for the defect D than the first optical system 10, the aforementioned on the surface of the wafer 1 is detected Defect D in the peripheral portion; a fog point D1 is extracted from a logical exclusive-OR of the defects D detected in each of the first step S10 and the second step S20.

Description

Wafer inspection method and wafer inspection device

The present invention relates to a wafer inspection method and a wafer inspection apparatus for inspecting the presence or absence of defects that may occur on a wafer surface, and more particularly, to a wafer inspection method capable of inspecting the presence or absence of fog spots on a peripheral portion of a wafer surface .

In order to improve the yield or reliability in the manufacturing process of a semiconductor device, the defect inspection technology of a wafer surface forming a semiconductor substrate becomes extremely important. There are many types of defects on the wafer surface, such as pits, crystal defects such as COP, uneven polishing and scratches caused by processing, and foreign matter (particles) attached to the wafer surface. In this specification, the description of the "wafer surface" refers to both the main surface on the front side and the main surface on the back side of the wafer, and when it refers to only one of the surfaces, it will be described separately.

Among the defects on the wafer surface, from the viewpoints of device characteristics, yield of device manufacturing, and the like, there are types of defects that do not cause problems even if they exist. On the other hand, there are disadvantages of types that are not allowed as products. Therefore, the wafer surface is inspected according to a predetermined judgment standard, and a good or defective product is judged.

In the past, an LPD (Light Point Defect) inspection device (laser surface inspection machine) was used to scan the mirror surface at the completion stage with laser light. The polished wafer surface is subjected to wafer inspection to detect scattered light due to particles or scratches existing on the surface. In addition, the laser of the laser surface inspection machine can measure sub-micron-level minute LPD, so it uses an optical system with a short wavelength and a small spot diameter. In addition, in the LPD inspection apparatus, in order to determine the presence or absence of difficult-to-resolve defects, it is also used to visually determine the appearance inspection of the wafer surface. The visual inspection is a sensory inspection, so it is impossible to avoid inconsistencies in the judgment of the inspector, and it takes time to make the inspector familiar with the inspection, so it is necessary to establish an objective inspection method and automatic inspection method.

Therefore, as one of the wafer inspection methods, the applicants of this application have proposed in Patent Document 1 a method for appropriately evaluating a wafer against defects on the surface of the wafer, especially on the back side, without relying on the appearance inspection. That is, a method for evaluating the back surface of a wafer includes a step of processing a distribution map, continuously capturing a part of the image of the back surface of the wafer along the circumferential direction of the wafer, and synthesizing the captured part of the image to make the entire back surface of the wafer. Image: and differential processing steps. Differentiate the entire image to produce a differentially processed image on the back of the wafer. Based on the entire image or the differentially processed image, detect uneven grinding, matte surfaces, scratches, and particles. Evaluation.

The optical system for producing the entire image of the wafer surface will be described using FIGS. 1 (A) and 1 (B). FIG. 1 (B) is a diagram showing the main part from FIG. 1 (A) in order to show the irradiated light L ₁ and the reflected light (scattered light) L ₂ irradiated by the ring-shaped optical fiber illumination 11. This optical system 10 includes a ring-shaped optical fiber illumination 11 and a first light receiving unit 12. The first light receiving unit 12 is, for example, a light receiving unit 14 composed of a telecentric lens 13 and a CCD camera. The light source of the ring-shaped optical fiber illumination 11 is composed of an ultra-high pressure mercury lamp. The irradiated light L ₁ irradiated by the ring-shaped optical fiber illumination 11 enters the wafer 1 at an angle of about 20 degrees with respect to the wafer surface, and when it collides with the defect D existing on the surface of the wafer 1, scattered light L ₂ is generated. The first light receiving unit 12 receives and captures the vertically scattered light among the scattered light L ₂ , and measures position information and brightness information of the first optical system 10.

The entire image of the wafer surface can be obtained by scanning the entire area of the wafer surface using the first optical system 10 and performing image processing. In order to shorten the scanning time, a plurality of first optical systems 10 are generally arranged on the front and back surfaces of the wafer. Figure 2 (A) is an example of the entire image on one side of a wafer obtained by using the first optical system 10, and Figure 2 (B) is a commercially available LPD inspection device (SP1; KLA-Tencor Corporation) Production) Measure the LPD distribution of the same wafer. As shown in FIG. 2 (A) and FIG. 2 (B), defects such as scratches and particles can be detected by any of the devices. In addition, in the case of a laser surface inspection machine, "blur" and "fogging" are detected as a small-sized LPD assembly. However, when the first optical system 10 is used, it is compatible with a laser surface inspection machine (LPD). Different inspection devices) can identify and detect defects called "fuzzy" or "fogging." However, the shape of these defects has a unique extended shape and is not dot-shaped. Therefore, these defects are considered to be excluded from the "dot-shaped" defects in this specification.

[Prior technical literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2010-103275

In this manner, by using a wafer inspection apparatus, various defects can be detected without relying on visual inspection. However, among the defects, there are spot-shaped defects with a diameter of about 5 to 3000 μm, which are called "fog spots". Such fog spots have not been detected without visual inspection. Following, use Figures 3 (A) ~ (C) illustrate the fog point and its generation mechanism.

The fog spot is formed in the following manner, for example. After the wafer 1 is polished, the wafer 1 is immersed in and washed with a cleaning solution, and then spin-dried to remove the cleaning solution. The centrifugal force acting on the wafer 1 during the spin drying allows the cleaning chemical component 2 in a mist state to remain on the peripheral portion of the wafer 1. The cleaning solution component 2 as a residue will dissolve the wafer material, such as silicon (Si), and also inhale oxygen (O2) from outside air (Figure 3 (A)). Then, when the cleaning solution component 2 evaporates, a circular pit is formed in a portion to which the cleaning solution component 2 is attached (it can be said that the wafer 1 is partially etched). Precipitates 2 'such as silicic acid (H ₂ SiO ₃ ) and potassium silicate (K ₂ SiO ₃ ) will be formed at the edges of the circular pits, forming a crater-shaped fog point D1. Once the fog point D1 is formed, even if polishing is performed again, the amount of grinding substitution is almost uniform on the surface, so the crater-shaped fog point D1 will continue to exist on the wafer 1 (FIG. 3C). The diameter of this fog point is about 5 to 3000 μm as described above. The width of the edge of the circular pit (mountain-shaped ring of the outer ring) is about 0.2 to 30 μm, and the height of this edge is about 0.1 to 30 nm. As such, the height of the edge of the fog point D1 is extremely smaller than the diameter and the width of the edge.

The shape and size of the fog point D1 are as described above. Therefore, the scattered light pattern caused by the fog point D1 is detected only on the periphery of the pit-shaped edge portion, and the inside of the pit-shaped edge portion is not detected. This is because there is almost no unevenness on the inner side of the crater-like edge portion, and a scattered light pattern similar to a flat surface without defects is formed. In this way, the fog point D1 is detected as a small LPD assembly in a conventional inspection device. In addition, when the width of the edge of the pit of the fog point is relatively large (for example, 2 μm or more), a scattered light pattern having the same defect size as a small-sized LPD is formed, and therefore it is difficult to distinguish. Crystal with fog In terms of quality control, Yuen is generally judged to be a defective product. Therefore, visual inspection has been used to ensure that there are no fog spots on the wafer. However, as mentioned before, the judge's judgment is required in appearance inspection, so an objective inspection method and automatic inspection method must be established.

Therefore, the present invention has been made in view of the above-mentioned problems, and an object thereof is to propose a wafer inspection method and a wafer inspection apparatus capable of inspecting the presence or absence of fog spots on a wafer surface.

In order to achieve the above-mentioned object, the present inventors made an effort to conduct a review and thought of replacing the light source of the first optical system 10 with an optical system of a laser light source to detect defects on the wafer surface. Therefore, the present inventors tried such an optical wafer inspection and confirmed that when the light source is a laser light source and the detection sensitivity is lower than that of the first optical system 10, the spot-shaped defects that can be detected do not include fog Point D1, and only particles are detected. As described above, in the first optical system 10, the defect D determined as a particle also includes the fog point D1. Therefore, only the fog point D1 can be extracted from the logical exclusive OR of the defects D detected by the two optical systems. The present inventors have completed the present invention based on the above findings. This invention is completed based on the said knowledge and review, The summary is as follows.

The wafer inspection method of the present invention includes a first step of detecting a point-like defect on a peripheral portion of a wafer surface using a first optical system including a ring-shaped optical fiber illumination and a first light receiving portion; and a second step, Using a second optical system having a laser light source and a second light receiving unit and having a lower detection sensitivity for the defect than the first optical system, the defect on the peripheral portion of the wafer surface is detected; from the first step And the logical exclusive OR of the defects detected in the second step Fog spots.

Here, it is preferable that the second optical system only detects the defect at the peripheral portion.

In addition, the defect detected in the first step is composed of particles and the fog point, and the defect detected in the second step is preferably composed of the particles.

The laser light source is preferably a blue LED laser.

The peripheral edge portion is preferably within a range of 3.5 mm from the outer edge of the wafer.

The lower limit of the detection sensitivity of the defect in the first optical system is 0.5 μm or less, and the lower limit of the detection sensitivity of the defect in the second optical system is preferably 1 μm or more.

A wafer inspection device according to the present invention includes a first optical system including a ring-shaped optical fiber illumination and a first light receiving unit; a second optical system including a laser light source and a second light receiving unit, and a detection sensitivity higher than that of the first optical system Low; a moving part that moves at least one of the wafer, the first optical system, and the second optical system; and a control part that controls the first optical system, the second optical system, and the moving part, wherein the The control unit controls the first optical system to detect a spot-shaped defect on a peripheral portion of the wafer surface, and controls the second optical system to detect the defect on the peripheral portion of the wafer surface, from the A fog point is extracted from a logical exclusive-OR of a defect detected by each of the first optical system and the second optical system.

According to the present invention, it is possible to provide a wafer inspection method and a wafer inspection device capable of inspecting the presence or absence of fog spots on a wafer surface.

1‧‧‧ wafer

2‧‧‧ washing liquid composition

2’‧‧‧ precipitate

3‧‧‧ rotating table

10‧‧‧1st optical system

11‧‧‧Ring Fiber Optic Lighting

12‧‧‧ 1st light receiving section

13‧‧‧ Telecentric lens

14‧‧‧Light receiving section

20‧‧‧The second optical system

21‧‧‧laser light source

22‧‧‧ 2nd light receiving section

30‧‧‧Mobile

50‧‧‧Control Department

100‧‧‧ Wafer Inspection Device

D‧‧‧ (spotted) defect

D1‧‧‧Fog point

D2‧‧‧ Particle

L ₁ ‧‧‧light

L ₂ ‧‧‧ scattered light

L ₃ ‧‧‧Illuminated

FIG. 1 is a schematic diagram illustrating a first optical system 10 used in an embodiment of the present invention. (A) is a schematic diagram showing the entirety of the first optical system 10, and (B) is a diagram showing the generation of the first optical system 10. A schematic diagram of the incident light L ₁ and the scattered light L ₂ .

FIG. 2 is an entire image of a wafer defect detected in a conventional example. (A) is an example of an entire image of a wafer defect obtained by the first optical system 10, and (B) is a commercially available LPD inspection. An example of an overall image of a wafer defect obtained by the device.

Figures 3 (A) to 3 (C) are schematic diagrams illustrating a mechanism for generating a fog point.

FIG. 4 is a flowchart illustrating a wafer inspection method according to an embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating a second optical system 20 used in an embodiment of the present invention.

FIG. 6 is a schematic plan view of a wafer inspection apparatus 100 according to an embodiment of the present invention.

FIG. 7 shows the fog points confirmed in the example in advance, (A) is an AFM image, and (B) is a graph showing its height.

Fig. 8 is a schematic diagram showing the positions of the fog spots in the embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 4 is a flowchart of a wafer inspection method according to an embodiment of the present invention. The first optical system 10 described in FIG. 1 and the first optical system 10 described in FIG. 5 will be described later. 2 optical system 20 to determine the presence or absence of fog. FIG. 6 is a schematic plan view of a wafer inspection apparatus 100 according to an embodiment of the present invention. The wafer inspection apparatus 100 includes the first optical system 10 and the second optical system 20 described above.

(Wafer Inspection Method)

As shown in FIGS. 4, 1, 5, and 6, a wafer inspection method according to an embodiment of the present invention includes a first step S10 using a first optical device including a ring-shaped optical fiber illumination 11 and a first light receiving unit 12. The system 10 detects a point-like defect D on the peripheral portion of the surface of the wafer 1. In the second step S20, the laser light source 21 and the second light receiving unit 22 are used, and the detection sensitivity of the defect D is higher than that of the first optical element. The second optical system 20 having a low system 10 detects a spot-shaped defect D on the peripheral edge portion of the surface of the wafer 1; and in step S30, the individual defects D detected from the first step S10 and the second step S20 are detected. The fog point is extracted from the logical XOR. Hereinafter, details of each step will be described in order.

First, in step S10, a point-like defect D on the peripheral edge portion of the surface of the wafer 1 is detected. This step can be performed in the same way as conventional techniques for detecting defects across the wafer surface. That is, the first optical system 10 described in FIG. 1 is used to irradiate a predetermined position on the peripheral edge portion of the surface of the wafer 1 to receive vertically scattered light due to a defect of the wafer 1 and measure the light at the predetermined position. Brightness information (hereinafter also referred to as "defect information"). In order to detect a micro-sized LPD, the lower limit of the detection sensitivity of the first optical system is preferably set to 1.0 μm or less, more preferably 0.5 μm or less, and even more preferably 0.1 μm or less. The smaller the lower limit of the detection sensitivity, the better, but it is not limited. For example, 0.01 μm can be used as an example. As the light source of the ring-shaped optical fiber illumination 10, an ultra-high pressure mercury lamp or the like can be used as described above. In addition, the direct field of illumination of the ring-shaped optical fiber illumination 10 The diameter can be, for example, 5 to 40 mm. From the obtained defect information, the position D and the defect D which is judged to be stray light by a conventional particle in the first optical system 10 are determined.

Here, as described above, the defect D which is determined to be a particle by the first optical system 10 also includes a fog point. Therefore, in the first step S10 using the first optical system 10, a point-like defect D composed of the fog point D1 and the particles D2 is detected. In other words, the point-like defect D detected in the first step S10 can be said to be composed of the particles D2 and the fog point D1.

In addition, as described in FIG. 3, the fog point D1 is formed on the peripheral portion of the surface of the wafer 1. Therefore, the detection performed in this step S10 may scan the first optical system on the entire surface of the wafer 1 to obtain defect information, and then obtain the entire information of the defect, or it may obtain particularly relevant points only on the periphery of the wafer 1. The defect information of the defect D. Further, in order to clearly determine the type of the defect as required, the differential information or the filtering process may be performed on the defect information to extract the spot-shaped defect D at the peripheral portion of the wafer.

In addition, the first optical system 10 can be provided with a plurality of arrays on both sides of the wafer surface to obtain defect information more quickly. When the first optical system 10 is scanned over the entire surface of the wafer 1, the first optical system 10 may be provided above and below the central portion of the surface of the wafer 1 in addition to the peripheral portion.

Next, in step S20, as shown in FIG. 5, using the second optical system 20 including the laser light source 21 and the second light receiving unit 22, the point-like defects D on the peripheral edge portion of the surface of the wafer 1 are aligned with the positions. And detect it. For example, the second optical system 20 may be fixedly installed on either or both above and below the peripheral edge portion of the wafer 1, the wafer 1 may be placed on the rotating table 3, and the wafer 1 may be rotated, To detect the defect D only at the peripheral portion of the wafer. Moreover, similarly to the first optical system 10, the second optical system may be scanned on the peripheral edge portion of the wafer.

Here, the detection sensitivity of the spot-shaped defect D of the second optical system 20 is a lower (inferior) sensitivity than that of the first optical system 10 in which a fog point cannot be detected. Under this limit, a person with a high detection sensitivity may be used, but in this case, it is preferable to set the lower limit of the detection sensitivity to 1 μm or less. If the detection sensitivity of the second optical system 20 is too good, as described below, both the fog point D1 and the particles D2 will be detected at the same time, and it will become impossible to use only the mist extraction point D1 in combination with the first optical system. . Although not limited, the spot diameter of the laser light used as such a detection sensitivity can be 70 μm to 270 μm as an example. When the wavelength of the laser light is in the visible range, blue (about 450 to 495 nm) is preferred.

Irradiation with a laser light source 21 at a predetermined position along the periphery of the wafer 1 to the second light receiving section 22 receives the irradiation light L scattered light ₃ generated when a case of obtaining scattered light intensity exceeds a predetermined threshold value, it is possible It is judged that the defect is caused by the particle D2. This is because the second optical system 20 is different from the first optical system 10 in that it uses a laser light source 21 whose wavelength of the irradiation light source is, for example, white light (380 nm to 800 nm). Therefore, the detection sensitivity of LPD is 2 μm or more, The intensity is such that the intensity of the scattered light from the fog point D1 can be judged to be a defect, but the intensity of the scattered light from the particle D2 can be judged to be a sufficient intensity. As such a laser light source 21, a blue LED laser can be used. However, the fog point D1 cannot be detected, but as long as it is a laser light source that can detect the particles D2, a metal halide lamp, a mercury lamp, or the like can also be used, and there is no particular limitation. As the second light receiving unit 22, for example, a CCD camera can be used.

As described above, the point-like defect D detected in the second step S20 using the second optical system 20 does not include the fog point D1 and only the particle D2 is detected. In other words, the spot-shaped defect D detected in the second step S20 is composed of the particles D2. In addition, the second optical system 20 can detect a large-scale flaw or a high-haze blur defect in addition to the spot-shaped defect D.

In addition, in the flowchart of FIG. 4, the illustration shows that the first step S10 is performed before the second step S20 is performed. However, this order may be exchanged, and any of the steps may be performed first. Between the first step S10 and the second step S20, the wafer 1 can be transported by the moving unit 30 (see FIG. 6). The moving unit 30 may include the rotating table 3 described above, or may include a scanning unit of the first optical system 10.

After the first step S10 and the second step S20, in step S30, a fog point is extracted from a logical exclusive OR (EX-OR) of each defect D detected in the first step S10 and the second step S20. As described above, the defect D detected in the first step S10 is the fog point D1 and the particles D2, and the defect D detected in the second step S20 is the particle D2, and the fog point D1 is not included. Therefore, if the logical XOR of the two is taken, only the fog point D1 can be extracted.

By performing the wafer inspection method of the first step S10 to the third step S30 described above, it is possible to inspect the presence or absence of fog spots on the wafer surface, particularly at the peripheral edge portion.

In addition, it is preferable that the wafer 1 is a mirror-processed silicon wafer. This is because, as mentioned above, it is very important to confirm that the fog point does not exist in the mirror-processed silicon wafer. need. In addition, the peripheral edge portion to be used for checking the presence or absence of a fog point can be set within a range of 3.5 mm or less than 3 mm at the outer edge of the wafer. As already explained, the fog spot exists only on the peripheral edge of the wafer, specifically within a range of 3.5 mm of the outer edge of the wafer. Therefore, if you narrow it to this range for inspection, the inspection time can be shortened. When it is limited to the range of 3.0 mm, the time can be further shortened. In addition, even if only one of the first step S10 and the second step S20 is performed to detect the defect D only at the peripheral portion of the wafer 1, the inspection time can be shortened.

(Wafer Inspection Device)

As schematically shown in FIGS. 6 and 1 and 5, a wafer inspection apparatus 100 according to an embodiment of the present invention includes a first optical system 10, a second optical system 20, a moving unit 30, and a control unit 50. The first optical system 10 includes a ring-shaped optical fiber illumination 11 and a first light receiving unit 12. The second optical system 20 includes a laser light source 21 and a second light receiving unit 22, and has a lower detection sensitivity than the first optical system 10. The moving unit 30 moves at least any one of the wafer 1, the first optical system 10, and the second optical system 20. The control unit 50 controls the first optical system 10, the second optical system 20, and the moving unit 30. Here, the control unit 50 controls the first optical system 10 to detect dot-like defects D on the peripheral edge portion of the surface of the wafer 1 and controls the second optical system 20 to detect dots on the peripheral edge portion of the wafer 1 surface. Then, the fog point D1 is extracted from the logical exclusive OR of the defects D detected by the first optical system 10 and the second optical system 20 respectively. In addition, in FIG. 6, each of the first optical system 10 and the second optical system 20 is shown in one set, but may be provided on the opposite side of the wafer 1 or a plurality of arrays may be provided. In order to receive the vertically scattered light of the defect D, the first optical system 10 and the second optical system 20 Circle 1 is preferably set vertically.

The control unit 50 can be realized by a suitable processor such as a CPU (Central Processing Unit) or MPU, and has a recording unit such as a memory or a hard disk. The control unit 50 executes the aforementioned wafers stored in the control unit 50 in advance. The program of the operation of the inspection method controls the information among the components of the wafer inspection apparatus 100, the transmission of instructions, and the operation of each part. The moving unit 30 may include a scanning unit that scans the first optical system 10. The scanning unit can be configured by an arm portion of a first light receiving portion 12 (a camera or the like) connected to the first optical system 10, a drive step motor, a servo motor, and the like for driving the arm portion. The moving unit 30 may include the same scanning unit that scans the second optical system 20, or may include a rotary table 3 that rotates the wafer 1. The unit provided with the first optical system 10 and the unit provided with the second optical system 20 may be separated from each other, and the moving unit 30 may be provided with a wafer loader that transports the wafer 1 to two divided regions.

[Example]

The embodiments of the present invention have been described above, but these are only examples of the embodiments. The present invention is not limited to these embodiments, and various changes can be made within the scope of the gist of the invention. The following examples do not limit the invention in any way.

In order to confirm that a fog point can be detected by the wafer inspection method according to an embodiment of the present invention, the following experiments were performed. First, a modified polished silicon wafer (so-called polished wafer (also called a PW wafer)) having a diameter of 300 mm and a thickness of 775 μm is prepared, and a visual inspection is performed on one side of the wafer in advance to confirm the silicon wafer. With or without fog.

Observing this fog point with AFM, as shown in Fig. 7 (A), it was confirmed that a pit-like defect was present. The height in the axial direction of Fig. 7 (A) is shown in Fig. 7 (B). The diameter of the fog point is 150 μm, the width of the edge is 20 μm, and the height of the edge is 18 nm.

The wafer inspection method according to the present invention is performed on a silicon wafer having this fog point. The lower limit of the detection sensitivity of the defect in the first optical system is 0.16 μm (that is, a point-like defect having a diameter of 0.16 μm or more can be detected), and the lower limit of the detection sensitivity of the defect in the second optical system is 5.0 μm (also That is, it is possible to detect spot-shaped defects having a diameter of 5.0 μm or more). First, through the first step S10 using the first optical system 10, spot-shaped defects on the peripheral edge portion of the wafer on the one-sided side were detected, and as shown in FIG. 8 (A), four spot-shaped defects were detected. defect. In addition, the symbol of the type of each defect is shown in Fig. 8 (A). However, at this stage, it cannot be confirmed whether the defect is the fog point D1 or the particle D2.

Next, through a second step S20 using the second optical system 20, a point-like defect D at the peripheral edge portion of the wafer is detected, and three point-like defects D are detected as shown in FIG. 8 (B). Since the defect detected in this step is the particle D2, the symbol of D2 is shown on the 8th (B) icon. In FIGS. 8 (A) and 8 (B), the wafer positions are aligned according to the groove positions (not shown) of the wafer (as a result, the positions of the defects D are also aligned). Obtain the logical XOR of the defect D obtained in the two steps (Figure 8 (C)). The defect that exists in the location of Figure 8 (A) but does not exist in Figure 8 (B) is the fog point D1. The defect is determined as particle D2. This judgment result is consistent with the result of a visual inspection performed in advance, and it was confirmed that the presence or absence of fog spots can be reliably detected by this inspection method.

[Possibility of industrial use]

According to the present invention, it is possible to provide a wafer inspection method and a wafer inspection apparatus capable of inspecting the presence or absence of fog spots on a wafer surface.

Claims (7)

A wafer inspection method includes a first step of detecting a spot-shaped defect on a peripheral portion of a wafer surface using a first optical system including a ring-shaped optical fiber illumination and a first light receiving unit; and a second step of using The second optical system of the laser light source and the second light-receiving portion that has a lower detection sensitivity than the first optical system detects the defect on the peripheral portion of the wafer surface; from the first step and The fog points are extracted from the logical exclusive-OR of the defects detected in the second step. The wafer inspection method according to item 1 of the patent application scope, wherein the second optical system only detects the defect at the peripheral portion. The wafer inspection method according to item 1 or 2 of the scope of patent application, wherein the defect detected in the first step is composed of particles and the fog point, and the defect detected in the second step is composed of The particles are composed. The wafer inspection method according to item 1 or 2 of the patent application scope, wherein the laser light source is a blue LED laser. The wafer inspection method according to item 1 or 2 of the patent application scope, wherein the peripheral edge portion is within a range of 3.5 mm of an outer edge of the wafer. According to the wafer inspection method described in the claims 1 or 2, the lower limit of the detection sensitivity of the defect in the first optical system is 0.5 μm or less, and the lower limit of the detection sensitivity of the defect in the second optical system. Above 1 μm. A wafer inspection device includes: a first optical system including a ring-shaped optical fiber illumination and a first light receiving unit; a second optical system including a laser light source and a second light receiving unit, and a detection sensitivity lower than the first optical system; A moving unit that moves at least one of the wafer, the first optical system, and the second optical system; and a control unit that controls the first optical system, the second optical system, and the moving unit, wherein the control unit Controlling the first optical system to detect spot-shaped defects on the peripheral portion of the wafer surface, and controlling the second optical system to detect the defects on the peripheral portion of the wafer surface, from the first The fog point is extracted from the logical exclusive-OR of the defects detected by the optical system and the second optical system.