JPH07146245A - Apparatus and method for detecting foreign matter - Google Patents

Abstract

PURPOSE:To provide a high-sensitivity detector for finding flaws and foreign particles smaller than 0.1mum. CONSTITUTION:A luminous flux linearlly polarized outputted from a laser oscillator 27 passes through a 1/2 wavelength plate 28, reflected on a reflection mirror 29 and then, it is condensed onto a semiconductor wafer 2 with a condenser lens 30 to make a small laser spot 31. The 1/2 wave plate 28 rotates centered on an optical axis and works to rotate the direction of polarization of a laser light oscillated with a laser oscillator 27 so that the laser light is adjusted to a P polarized light with respect to the semiconductor wafer 2. Scattered light received with a photodetecting system made up by combining a fiber plate 32 and a photo-multiplier tube 33 is converted to an electric signal with the photomultiplier 33. The electric signal to be outputted from the photomultiplier 33 is amplified with an amplifying section 34 and a computation is performed with a detecting section 35 thereby detecting the presence of foreign matter and flaws and the position thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to foreign matter inspection, and more particularly to a foreign matter inspection apparatus and a foreign matter inspection method for detecting fine foreign matter on a semiconductor wafer or a liquid crystal substrate.

[0002]

2. Description of the Related Art An apparatus used for surface inspection is one in which laser light is applied to the surface of an object to be inspected and the scattered light is received to measure the shape of the surface of the object to be inspected and inspect foreign matters. is there.
As a technique used for these inspections, there is a method called a flying spot method. In this flying spot method, for example, parallel laser light output from a laser light source is focused by a lens system, and then the light beam is irradiated onto a surface of an object to be inspected by an optical scanning means to scan the object to be inspected. The reflected laser light or the transmitted light from the surface is received by the light reception detection system and photoelectrically converted. Then, the electric signal after photoelectric conversion is processed to obtain an inspection result.

FIG. 19 is a block diagram of a foreign matter inspection apparatus to which the flying spot method is applied (first conventional example). A semiconductor wafer 2 is mounted on the mounting table 1. On the other hand,
The laser light output from the oscillator 3 is formed into parallel light by the collimator lens 4 and sent to the galvano mirror 5. The galvano mirror 5 scans parallel light and irradiates the surface of the semiconductor wafer 2 at an angle within a predetermined range through a condensing optical system 6. At this time, the condensing optical system 6 shapes the parallel light into a spot light. Therefore, the semiconductor wafer 2 is scanned with the laser spot light.

A line sensor 7 and light receiving elements 8 and 9 are arranged above the semiconductor wafer 2. The line sensor 7 is arranged at a position for receiving the regular reflection laser light from the semiconductor wafer 2, and the respective light receiving elements 8 and 9 are arranged at a position for receiving the scattered light from the semiconductor wafer 2.
The electric signals output from the line sensor 7 and the light receiving elements 8 and 9 are sent to a measuring circuit 10. The measuring circuit 10 determines from the electric signals whether the surface of the semiconductor wafer 2 is scratched or foreign matter is attached. To do.

Next, as another technique, there is an inspection apparatus shown in FIG. 20 (second conventional example). The semiconductor wafer 2 is placed on the XY table 11. A container 12 is arranged just above the semiconductor wafer 2. This container 1
2 is formed in a hemispherical shape, and a plurality of light receiving elements 13 are provided on the inner surface thereof. On the other hand, the laser oscillator 3 is arranged above the XY table 11. The laser light output from the laser oscillator 3 passes through the condensing optical system 14, the half mirror 15 and the container 12 and is applied to the semiconductor wafer 2.

In this case, the laser light is applied to the semiconductor wafer 2 in the vertical direction. Accordingly, the scattered light from the semiconductor wafer 2 is received by each light receiving element 13. The regular reflection light from the semiconductor wafer 2 reaches the half mirror 15, is reflected by the half mirror 15, passes through the condensing optical system 16, and is received by the light receiving element 17. Then, the electric signal output from each of the light receiving elements 13 and 17 is sent to the measuring circuit 18, and the measuring circuit 18 judges from the respective electric signals whether the surface of the semiconductor wafer 2 is scratched or foreign matter is attached.
In this case, the position of the scratch or foreign matter on the surface of the semiconductor wafer 2 is measured by the position of the light receiving element 13 that receives the scattered light.

The XY table 11 is controlled and driven by an XY table controller 19 so that laser light scans the semiconductor wafer 2. Further, the technology disclosed in Japanese Patent Application Laid-Open No. 3-128445, which is our earlier application, is as shown in FIGS. 21 and 22 (third conventional example). Figure 2
As shown in FIG. 1, the semiconductor wafer 2 is placed on the XYθ table 20.
Is placed.

On the other hand, a laser oscillator 3 is provided and this laser oscillator 3 is provided.
The collimator lens 4 and the reflection mirror 21 are sequentially arranged on the optical axis of the laser light output from the oscillator 3.
A galvano mirror 5 is arranged on the reflection laser optical path of the reflection mirror 21. The laser light scanned by the galvanometer mirror 5 is applied to the surface of the semiconductor wafer 2 via the condensing optical system 22. In this case, the scanning plane of the laser light scanned by the galvanometer mirror 5 is perpendicular to the surface of the semiconductor wafer 2.

Each line sensor 7 is arranged above the semiconductor wafer 2. These line sensors 7
Is parallel to the scanning direction of the laser light and is an angle φ ₁ (5 ° ≦ φ ₁ ≦ with respect to the irradiation position of the laser light as shown in FIG.
It is arranged at a position for receiving scattered light at an angle of 40 °. The electric signals output from these line sensors 7 are sent to the detection unit 23.

The detection unit 23 has a function of receiving each electric signal and judging from the electric signals whether or not the surface of the semiconductor wafer 2 is scratched or foreign matter is attached. by the way,
In JP-A-64-3545, from page 12, upper left column, line 12 to page 2, upper right column, fourth line, S () is formed at a predetermined portion of the patterned wafer surface rotated in a predetermined plane. Senkrec
ht) A technique for detecting foreign matter adhering to a pattern by scanning while irradiating P (Parallel) polarized light at the same time as irradiating polarized light and detecting the light amount of a predetermined polarized component contained in the reflected light is disclosed. (Fifth conventional example). Although this foreign patent publication does not show a drawing of this foreign matter inspection device, it is considered that the device shown in FIG.

In addition, Japanese Patent Laid-Open No. 64-3545 and Japanese Patent Laid-Open No.
There is also an inspection device as disclosed in Japanese Patent Laid-Open No. 5-18889, which is provided with a plurality of photodetectors and inspects foreign matter by obtaining a ratio of the light intensities detected by the photodetectors (sixth conventional example). . These devices eliminate the drawbacks of the fifth conventional example.

Further, in JP-A-61-180128 and JP-A-2-284047, a plate-like material is irradiated with polarized light, and the resulting reflected light or scattered light is polarized by a polarizing means. There is also shown an inspection device which detects the foreign matter afterward and inspects the foreign matter based on these results (seventh conventional example).

[0013]

The conventional foreign matter inspection apparatus having the above-mentioned structure has the following problems. First, in recent development demands, semiconductors and magnetic materials having higher storage capacities are demanded. With these developed products, even minute scratches and foreign substances, for example, those having a size of about 0.1 μm, are It will affect the quality.

On the other hand, in the above-mentioned first conventional example and the second conventional example, it is only possible to detect scratches or foreign matters having a size of 0.3 μm or more on a semiconductor wafer having a mirror surface or an oxide film. Then, on a semiconductor wafer having a surface coating such as a metal film, it is only possible to detect scratches and foreign matters having a size of 0.5 μm or more.

That is, in the above-mentioned first conventional example and the second conventional example, a small part of the specularly reflected light incident on the light receiving elements 8, 9, and 13 is distinguished from a scratch or foreign matter having a size of about 0.1 μm. Therefore, scratches and foreign matters having a size of about 0.1 μm are also detected as noise.

Further, in the third conventional example, it becomes possible to detect scratches and foreign matters having a size of about 0.1 μm on a semiconductor wafer having a mirror surface or an oxide film, but random polarized light is used as a light source. 0.1 μm because not only scattered light of scratches and foreign matters of about 0.1 μm but also scattered light of the main body of the semiconductor wafer 2 is detected by the light receiving elements 8, 9 and 13.
There is a drawback that it is difficult to detect scratches and foreign matters of the following sizes. On a semiconductor wafer having a surface coating such as a metal film, it is similarly difficult to detect a scratch or foreign matter having a size of 0.2 μm or less.

However, in the manufacturing process of semiconductors of the 64M DRAM and later generations, which is currently under development, it is necessary to detect scratches or foreign matters having a size of about 0.1 μm or less on a semiconductor wafer having a mirror surface or an oxide film. On a semiconductor wafer having a surface coating such as a metal film, it has been necessary to detect scratches and foreign matters having a size of about 0.2 μm or less. Therefore, it has been desired to improve the detection sensitivity of scratches and foreign matter on the semiconductor wafer as compared with the conventional foreign matter inspection apparatus.

Further, referring to the fifth conventional example to the seventh conventional example, first, the fifth conventional example can be detected only in a wafer having a single-layer pattern formed on its surface. Therefore, it is not possible to deal with a multilayer pattern, and a step of extracting a predetermined polarization component contained in the reflected light has to be performed.

In the sixth conventional example, a plurality of detectors must be installed, and in addition, it is necessary to obtain a ratio of detection intensities of P-polarized light and S-polarized light. The signal processing method was complicated.

In the seventh conventional example, after the reflected light or the scattered light is polarized by the polarization means, the foreign matter must be detected for each polarization component, so that the device configuration is complicated and the signal processing method is It was complicated.

Further, in the conventional method, as shown in FIG. 24, a detection intensity curve having a good linear characteristic is obtained for a foreign substance having a particle size within a specific range (here, about 0.1 μm to about 0.2 μm). However, the linear characteristic of this detection intensity curve is deteriorated for foreign substances having a larger particle diameter, and it is difficult to specify the exact foreign substance size from the scattered light intensity.

[0022]

SUMMARY OF THE INVENTION The present invention has been made to solve the above technical problems, and in a foreign matter inspection apparatus for inspecting fine foreign matter on the surface of an object to be inspected, a light source, Condensing means for condensing only the P-polarized light component emitted from the light source on the surface of the object to be inspected, and scanning means for relatively scanning the surface of the object to be inspected with the spot light condensed by the light condensing means. And a light receiving means for directly receiving the light scattered at an angle of 5 to 40 degrees with respect to the surface of the object to be inspected with reference to the irradiation position of the spot light scanned by the scanning means, and the light receiving intensity by the light receiving means. (EN) A foreign matter inspection apparatus and a method thereof, further comprising a detection means for detecting foreign matter on the surface of an object to be inspected.

Further, the present invention is a foreign matter inspection apparatus for inspecting fine foreign matter on the surface of an object to be inspected, and a light source and a condenser for condensing only the S-polarized component emitted from this light source on the surface of the object to be inspected. Means, scanning means for relatively scanning the spot light focused by the focusing means onto the surface of the object to be inspected, and the surface of the object to be inspected on the basis of the irradiation position of the spot light scanned by the scanning means. 65 to 9 degrees
A foreign matter inspection apparatus comprising: a light receiving means for directly receiving light scattered at an angle of 0 degree; and a detecting means for detecting a foreign matter on the surface of the object to be inspected based on the intensity of light received by the light receiving means, and the same. It provides a method.

Further, according to the present invention, in a foreign matter inspection apparatus for inspecting fine foreign matter on the surface of an object to be inspected, a light source and a polarization component for varying the polarization angle of light emitted from the light source according to the type of the object to be inspected. The varying means, a condensing means for condensing the light emitted from the polarization component varying means on the surface of the object to be inspected, and the spot light condensed by the condensing means relative to the surface of the object to be inspected. Scanning means for scanning, light receiving means for directly receiving the light scattered at a predetermined angle with respect to the surface of the object to be inspected with reference to the irradiation position of the spot light scanned by the scanning means, and light receiving intensity by the light receiving means. (EN) A foreign matter inspection apparatus and a method thereof, further comprising a detection means for detecting foreign matter on the surface of an object to be inspected.

Further, according to the present invention, in a foreign matter inspection apparatus for inspecting fine foreign matter on the surface of an object to be inspected, a light source and a polarization component separating means for separating the light emitted from the light source into a P-polarized component and an S-polarized component. A first light collecting means and a second light collecting means for respectively collecting the P polarized light component and the S polarized light component of the light separated by the polarized light component separating means on the surface of the object to be inspected, respectively. Scanning means for relatively scanning the surface of the object to be inspected with the first spot light and the second spot light condensed by the first condenser means and the second condenser means; and the scanning means. First light receiving means and second light receiving means for directly receiving the light scattered from the irradiation positions of the first spot light and the second spot light, respectively, and the first light receiving means and the second light receiving means.
Selecting means for selecting the first received light intensity and the second received light intensity by the second light receiving means and the second light receiving means, and the first received light intensity or the second received light intensity selected by the selecting means. The present invention provides a foreign matter inspection apparatus and a method thereof, comprising a detection means for detecting foreign matter on the surface of the inspection body.

[0026]

The foreign matter inspecting apparatus and the foreign matter inspecting method of the present invention improve the detection sensitivity of scratches and foreign matters by a simple configuration using a P-polarized light or S-polarized light for the light source of the third conventional example among the above-mentioned conventional examples and a signal processing method. It is possible to increase scratches and foreign matters of 0.1 μm or less on a semiconductor wafer having a mirror surface or an oxide film, and scratches and foreign matters of 0.2 μm or less on a semiconductor wafer having a surface coating such as a metal film. I am trying to detect it.

Further, by switching between P-polarized light and S-polarized light, it is possible to adjust the polarization ratio to 0.1 on a semiconductor wafer wafer having a mirror surface or an oxide film.
A P-polarized light is used to detect a scratch or foreign matter having a size of μm or less to enhance the detection sensitivity of the scratch or foreign matter. S-polarized light is used to detect scratches and foreign matters having a size of 0.2 μm or less on a semiconductor wafer having a surface coating of a metal film, and the sensitivity of detecting scratches and foreign matters is enhanced. Then, the detection data of the P-polarized light and the detection data of the S-polarized light are selected and used according to the range of the particle size of the foreign matter, thereby enhancing the detection sensitivity of the scratch and the foreign matter.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIG. 1 and the configuration of this embodiment will be described in detail below. The semiconductor wafer 2 to be inspected is mounted on a mounting table 26 that is a combination of a θ table 24 and an X table 25. The light irradiation system is composed of an Ar ⁺ laser oscillator 27 (wavelength: 488 nm) that outputs linearly polarized light, a half-wave plate 28, a reflection mirror 29, and a condenser lens 30. The linearly polarized light beam output from the laser oscillator 27 passes through the half-wave plate 28, is reflected by the reflection mirror 29, and is then made into a small laser spot 31 on the semiconductor wafer 2 by the condenser lens 30. Collected. Since the 1/2 wave plate 28 has a function of rotating the polarization direction of the laser light oscillated by the laser oscillator 27 by rotating about the optical axis, the laser light is emitted to the semiconductor wafer. For 2, the P (Parallel) polarization is adjusted.
When the polarization angle to be used is fixed (P polarization in this case), the ½ wavelength plate 28 may be fixed in advance at a predetermined angle without being rotated about the optical axis.

The light receiving system is constructed by combining a fiber plate 32 and a photomultiplier tube 33. The light receiving system has an angle φ _{2 with} respect to the laser irradiation position as shown in FIG.
(Here, φ ₂ is approximately 25 °). Further, the light receiving system measures the side scatter caused by the foreign matter.

The scattered light received by the light receiving system is converted into an electric signal by the photomultiplier tube 33. The electric signal output from the photomultiplier tube 33 is amplified by the amplification unit 34, and then calculated by the detection unit 35 to detect the presence or absence of foreign matter or scratches and the position thereof. The semiconductor wafer 2 is linearly moved in the diameter direction of the semiconductor wafer 2 by the X table 25 while being rotated by the θ table 24. As a result, the laser spot 31 spirally scans the entire surface of the semiconductor wafer 2 when the mounting table 26 is controlled by a controller (not shown).

When the laser spot 31 scans the surface of the semiconductor wafer 2, if a foreign matter or a scratch is present in the spot, strong scattered light is detected by the light receiving system, but the foreign matter or the scratch is present in the spot. Even when there is no light, weak scattered light (noise) of the semiconductor wafer 2 body is detected by the light receiving system. Here, the signal component (S component) is detected by the strong scattered light, and the noise component (N component) is detected by the weak scattered light.

By the way, the distribution of scattered light due to foreign matter and scratches differs depending on the polarization direction of the irradiation light. FIG. 3 shows the intensity distribution of scattered light due to foreign matter and scratches when the angle φ ₂ with respect to the laser irradiation position shown in FIG. 2 is changed. In the case of P-polarized light, the maximum value of the intensity distribution of scattered light exists in a region close to the surface of the semiconductor wafer 2, that is, a region having a small angle φ ₂ . On the other hand, in the case of S (Senkrecht) polarization, the maximum value of the intensity distribution of scattered light exists in a region isolated from the surface of the semiconductor wafer 2, that is, a region having a large angle φ ₂ . The position is detected as a place on the semiconductor wafer 2 where foreign matter or scratches exist.

As shown in FIG. 3, the scattered light of the main body of the semiconductor wafer 2 is scattered in a region separated from the surface of the semiconductor wafer 2 for P-polarized light, S-polarized light and random polarized light, that is, a region having a large angle φ ₂ . Strength increases. Since the unit of light intensity uses relative intensity, it is not specified in FIG. From the result of FIG. 3, the intensity ratio between the signal component (S component) due to the strong scattered light and the noise component (N component) due to the weak scattered light, that is, S /
When N is calculated, it becomes as shown in Fig. 4.

In the third conventional example having a structure similar to that of the present invention, random polarization was applied without considering the polarization direction of the irradiation light. Here, the polarization direction of random polarization is statistically P
It is considered to be approximately in the middle of the polarization directions of the polarized light and the S-polarized light, that is, approximately 45 °. As a result, the intensity distribution of scattered light due to a foreign substance or a scratch is an average of intensity distributions of P-polarized light and S-polarized light as shown in FIG. 3, and does not change abruptly as compared with the case of P-polarized light and S-polarized light alone. . In short, the maximum part of the intensity distribution of scattered light does not protrude, so the S /
Since N could not be increased, it was not possible to improve the detection sensitivity.

From the results shown in FIGS. 3 and 4, the intensity of scattered light becomes larger in the region where the weak scattered light of the semiconductor wafer 2 body is separated from the surface of the semiconductor wafer 2, that is, in the region where the angle φ ₂ is larger. Therefore, even if the surface of the semiconductor wafer 2 is irradiated with random polarized light or S-polarized light, the maximum part of the intensity distribution of scattered light is in a region isolated from the surface of the semiconductor wafer 2, that is, a region having a large angle φ _2. It can be seen that it is not possible to raise the S / N of the detection signal for foreign matter or scratches because it is present.

On the other hand, by irradiating the surface of the semiconductor wafer 2 with P-polarized light, the scattered light of a region close to the surface of the semiconductor wafer 2, that is, a region having a small angle φ ₂ is received and a higher detection signal of foreign matter or scratches is obtained. You can see that you can get the S / N of. Therefore, with the configuration of such a foreign matter detection device, it is possible to enhance the detection sensitivity and detect scratches and foreign matter having a size of 0.1 μm or less, which is smaller than conventional ones. The semiconductor wafer 2 to be inspected in the present embodiment preferably has a mirror surface or a surface coating such as an oxide film.

The present invention is not limited to the first embodiment, but various modifications can be made. In the second embodiment, the scanning of the laser spot 31 is made spiral by moving the semiconductor wafer 2 with the X table 25 while rotating the semiconductor wafer 2 with the θ table 24 as in the first embodiment. Although it has been performed, it is conceivable to scan the semiconductor wafer 2 in the XY directions using the XY table.

In the third embodiment, the light receiving system in the first embodiment uses the fiber plate 32 to collect scattered light, but the optical system uses a lens instead of the fiber plate 32. It is also conceivable to design a system (not shown) to collect scattered light.

Next, a fourth embodiment of the present invention is shown in FIG. 5, and the configuration of this embodiment will be described in detail below. This embodiment comprises a laser irradiation system 36, a control system 37, a scanning system 38, a detection system 39, and a signal processing system 40.

The laser irradiation system 36 outputs linearly polarized light.
An Ar ⁺ laser oscillator 41 and a beam expander 42 expand the beam, pass through a half-wave plate 43, and a reflection mirror 44 and a condenser lens 45 are used to irradiate a surface of a semiconductor wafer 46 with a small spot (hereinafter referred to as an irradiation surface). It is described as a laser spot)
It is condensed so as to form 47.

At this time, the half-wave plate 43 is rotated by a motor (not shown) according to a control signal (first signal) from the control circuit 48. By the movement of the half-wave plate 43, the polarization direction of the laser light transmitted through the half-wave plate 43 can be freely changed.

The control system 37 is composed of a computer 49, an interface circuit 50, and a control circuit 48. The control system 37 includes a signal that changes the polarization direction of the laser light that passes through the half-wave plate 43 (first signal) and a signal that selects the detector 53 and the detector 54 in the detection system 39 (first signal). 2) and a signal (third signal) for controlling the movement of the scanning system 38.

The scanning system 38 includes a mounting table 51 on which the semiconductor wafer 46 is mounted, a θ table 52, and an X table 5.
3 and 3. Since the laser spot 47 is fixed, the operation of the θ table 52 and the X table 53 scans the entire surface of the semiconductor wafer 46.

Specifically, according to a control signal (third signal) from the control system 37, the θ table 52 makes a rotational movement at a predetermined speed, and the X table 53 makes a linear movement at a predetermined pitch. By combining these, laser spot 4
7 scans the entire surface of the semiconductor wafer 46 in a spiral shape.

The detection system 39 (light receiving system in the first embodiment) is composed of a detector 54 and a detector 55. Then, the detector 54 is a fiber plate 56.
And a photomultiplier tube 57, and a detector 55
Is composed of a fiber plate 58 and a photomultiplier tube 59. The fiber plates 56, 58
The operation of the photomultiplier tubes 57 and 59 is similar to that of the first embodiment.

Then, as shown in FIG. 6, the laser spot 4
Centering on the irradiation position of 7, the detector 54 is arranged at a position where φ ₃ is approximately 35 ° with respect to the surface of the semiconductor wafer 46 and θ ₁ is approximately 90 ° with respect to the laser incident surface. Here, the laser incident surface refers to a surface perpendicular to the surface formed by the laser incident light and the laser reflected light. Further, the detector 55 is arranged at a position where φ ₄ is approximately 80 ° with respect to the surface of the semiconductor wafer 46 and θ ₂ is approximately 135 ° with respect to the laser incident surface.

Next, depending on whether the semiconductor wafer 46 is a mirror surface type, a type having an oxide film surface coating, or a type having a metal film surface coating, the control system 37 detects the detector 54 and the detector in the detection system 39. A signal (second signal) for selecting 55 is output to operate one of the detector 54 and the detector 55. Here, it is assumed that the type of the semiconductor wafer 46 is automatically identified by the foreign substance inspection apparatus of the present invention, or is input in advance by the measurer.

The signal processing system 40 is composed of a hardware section and a software section. The hardware section amplifies the detected signal due to the scattered light from the semiconductor wafer 46 in order to increase the resolution of the signal in the interface circuit 50, and an A / D circuit for this signal.
An interface circuit 50 for D-converting and fetching the result into the computer 49, and the computer 49. Software Department is Computer 4
It is constituted by a data processing program for arithmetically processing the signal (digital value) by the scattered light fetched in 9 and discriminating presence / absence of foreign matter, position of foreign matter, and size of foreign matter.

The operation of this embodiment is as follows. First, the type of the semiconductor wafer 46 to be inspected (a semiconductor wafer having a mirror surface, a semiconductor wafer having an oxide film, a semiconductor wafer having a metal film) is registered in the computer 49. The control system 37 includes a laser irradiation system 36, a scanning system 38,
Appropriate control signals are sent to the detection system 39. FIG. 7 shows a specific control flow of the selection process, which will be described in detail below.

First, the control signal (first signal) for the laser irradiation system 36 will be described. When the type of the semiconductor wafer 46 to be inspected is registered as a semiconductor wafer having a mirror surface or a semiconductor wafer having an oxide film, the control system 37 outputs a first signal for selecting P-polarized light. Then, a motor (not shown) rotates in accordance with the first signal, and the 1/2 wavelength plate 43 rotates about the optical axis up to a predetermined angle. By this rotation, the polarization state at the laser spot 47 on the semiconductor wafer 46 becomes P-polarized.

On the other hand, if the type of the semiconductor wafer 46 to be inspected is registered as a semiconductor wafer having a metal film, S
The control system 37 outputs a first signal for selecting the polarization. Then, a motor (not shown) rotates in accordance with the first signal, and the 1/2 wavelength plate 43 rotates about the optical axis up to a predetermined angle. By this rotation, the polarization state at the laser spot 47 on the semiconductor wafer 46 becomes S-polarized.

Next, the control signal (second signal) for the detection system 37 will be described. When the type of the semiconductor wafer 46 to be inspected is registered as a semiconductor wafer having a mirror surface or a semiconductor wafer having an oxide film, the control system 37 outputs a second control signal for operating the detector 54.

On the other hand, when the type of the semiconductor wafer 46 to be inspected is registered as a semiconductor wafer having a metal film, the control system 37 outputs a second control signal for operating the detector 55. In this way, the detectors 54 and 55 that detect the signal due to the scattered light are automatically switched for each type of the semiconductor wafer 46.

When the polarization state and the detector selection are completed,
The semiconductor wafer 46 is scanned with laser light and inspected for foreign matter. The θ table 52 starts to rotate at a predetermined speed in response to a third control signal from the control system 37. Also, θ
When the table 52 starts to rotate, the X table 53 starts linear movement at a predetermined pitch. With this combination, the laser spot 47 spirally scans the surface of the semiconductor wafer 46.

At this time, if a foreign matter is present on the irradiation surface of the laser spot 47, the foreign matter strongly scatters the laser beam. The selected detector 54 or detector 55 detects this scattered light. Then, the signals due to the scattered light are photoelectrically converted by the photomultiplier tube 57 or the photomultiplier tube 59, respectively, and the detection signal is further amplified by the amplifier circuit 60, and passed through the interface circuit 50 to the computer 4
Taken in 9.

Then, the size of the foreign matter is estimated from the intensity of the signal due to the scattered light after being processed by the data processing program,
The existence position of the foreign matter is calculated back from the scanning positions of the θ table 52 and the X table 53. By repeating such scanning, the scattered light is detected while scanning the entire surface of the semiconductor wafer 46, and information such as the number of foreign matters adhering to the surface of the semiconductor wafer 46 and their positions and sizes can be obtained. .

Finally, by the operation of this embodiment described above,
Specific data showing that it is possible to detect foreign particles of 0.1 μm or less in a semiconductor wafer having a mirror surface or a semiconductor wafer having an oxide film, and to detect foreign particles of 0.2 μm or less in a semiconductor wafer having a metal film. Explain.

First, the criteria for determining whether or not a foreign substance can be detected using S / N will be described. Laser spot 4
If a foreign substance is present on the irradiation surface of the laser spot 47 when the surface of the semiconductor wafer 46 is scanned by 7, the signal due to the scattered light from this foreign substance is detected. This is a signal component (S). Further, when the laser spot 47 scans the surface of the semiconductor wafer 46, foreign matter may be generated by the laser spot 4.
7 is not on the irradiation surface, the semiconductor wafer 46
The signal due to the scattered light from the surface roughness of is detected. This is a noise component (N).

The ratio of the signal component (S) and the noise component (N) thus detected, that is, S / N is the most important parameter that determines the detection sensitivity of the foreign matter inspection apparatus of the present invention, and is generally , The condition of S / N ≧ 3 specified in the pulse practical measurable particle size of JIS standard (JIS B 9924) is satisfied,
It serves as a criterion for determining that the foreign matter can be detected.

Therefore, when inspecting the foreign matter on the semiconductor wafer 46, it is desirable to perform the measurement so that the signal component (S) is large and the noise component (N) is small. However, the signal component (S) due to the scattered light from the foreign matter and the semiconductor wafer 4
The spatial distribution with the noise component (N) due to the scattered light from the surface roughness of 6 largely differs depending on the material of the surface of the semiconductor wafer 46 and the polarization state of the laser spot 47 on the semiconductor wafer 46. Without consideration, it is difficult to perform measurement so that the signal component (S) is large and the noise component (N) is small.

The measured values are shown here. FIG. 8A is a graph showing the relationship between the S / N when a semiconductor wafer having a mirror surface (mirror wafer) is irradiated with P-polarized light and the angle φ ₃ formed by the detection system 37 with respect to the surface of the semiconductor wafer 46. is there. It is assumed that foreign matter having a diameter of 0.1 μm or less adheres to the surface of the semiconductor wafer 46. Further, FIG. 8 (b) shows the case of irradiation with S-polarized light.
6 is a graph showing the relationship between S / N and the angle φ ₄ formed by the detection system 37 with respect to the surface of the semiconductor wafer 46. Here, a state is shown in which θ is approximately 45 ° (backscattering), θ is approximately 90 ° (side scattering), and θ is approximately 135 ° (forward scattering) with respect to the laser incident surface. These graphs show the spatial distribution of the signal component (S) due to the scattered light from the foreign matter on the semiconductor wafer 46 and the noise component (N) due to the scattered light from the surface roughness of the semiconductor wafer 46. There is.

From these measured values, in the case where the semiconductor wafer 46 has a mirror surface, a spatial distribution region having an S / N of 3 or more when measuring a foreign substance on the semiconductor wafer 46 is found, and the S / N of this region is determined. Even if the semiconductor wafer 46 has a mirror surface, if the detection system 37 is arranged at the position showing the peak, it is 0.1 μm.
It is possible to detect foreign matter of m or less with optimum detection sensitivity.

From the measured values shown in FIGS. 8A and 8B, when the semiconductor wafer 46 has a mirror surface, P-polarized light is irradiated and the detector (that is, the detector 54) is placed on the surface of the semiconductor wafer 46. On the other hand, if φ ₃ is arranged at a position of about 35 ° and θ is arranged at a position of about 90 ° (which becomes θ ₁ ) with respect to the laser incident surface, it is understood that the foreign matter can be detected with the best sensitivity.

The same measurement as described above is performed on the semiconductor wafer 46 under other conditions. Here, it is assumed that foreign matter having a diameter of 0.2 μm or less is attached to the surface of each semiconductor wafer 46. The measurement results when the semiconductor wafer 46 has an oxide film (wafer with an oxide film) are shown in FIGS. 9A and 9B, and when the semiconductor wafer 46 has a metal film (a wafer with a metal film). The measurement results are shown in FIGS. 10 (a) and 10 (b). These graphs also show the spatial distribution of the signal component (S) due to the scattered light from the foreign matter on the semiconductor wafer 46 and the noise component (N) due to the scattered light from the surface roughness of the semiconductor wafer 46. There is. Then, these results are analyzed similarly to the case where the semiconductor wafer 46 has a mirror surface.

As a result, when the semiconductor wafer 46 has an oxide film, it is irradiated with P-polarized light and a detector (that is, the detector 5).
4) substantially 35 ° to phi ₃ with respect to the surface of the semiconductor wafer 46
The angle θ is about 90 with respect to the laser incident surface.
It can be seen that foreign matter can be detected with the best sensitivity if it is placed at a position of ° (becomes θ ₁ ).

Further, when the semiconductor wafer 46 has a metal film, it is irradiated with S-polarized light and a detector (that is, the detector 5
5) with respect to the surface of the semiconductor wafer 46 with φ _{4 set} to about 80 °
The angle θ is about 13 with respect to the laser incident surface.
It can be seen that the foreign matter can be detected with the best sensitivity if it is arranged at the position of 5 ° (which becomes θ ₂ ).

From the above measurement results, when measuring a semiconductor wafer having a mirror surface or a semiconductor wafer having an oxide film, P-polarized light is irradiated and detection is performed using the detector 54 to measure a semiconductor wafer having a metal film. In this case, it is clear that it is better to irradiate S polarized light and perform detection using the detector 55. Therefore, the polarization state and the detectors 54 and 55 are automatically determined according to the type of the semiconductor wafer 46 by the configuration described above. Foreign matter can be detected with the best sensitivity regardless of the type of the semiconductor wafer 46.

Here, as a modification of the fourth embodiment explained in detail above, the laser spot 47 is scanned by the X table 53 while rotating the semiconductor wafer 46 by the θ table 52 as in the fourth embodiment. Although the semiconductor wafer 46 is spirally moved by moving the semiconductor wafer 46, it is possible to scan the semiconductor wafer 46 in the XY directions by using an XY table (fifth embodiment).

Furthermore, in the fourth embodiment, the detection system 39
Collects scattered light using the fiber plates 56 and 58, but collects scattered light using an optical system (not shown) using lenses instead of the fiber plates 56 and 58. Can also be considered (sixth embodiment).

The above is summarized in the following [Table 1].

[0071]

[Table 1]

By the way, the fourth embodiment, the fifth embodiment,
In the sixth embodiment, the detection system 39 comprises two detectors 5.
It is also possible to use a single detector by moving the position in the φ direction or the θ direction according to the type of the semiconductor wafer to be measured by using a moving means (not shown) without using 4.55. Φ corresponding to the type of the semiconductor wafer 46
It is also possible to use a plurality of detectors in which .theta. And .theta. Are set to appropriate angles, and .phi. And .theta. May be variable. That is, φ and θ are not limited to the above numerical values. This is because in the above embodiment, side scattered light is used when measuring a semiconductor wafer having a mirror surface or a semiconductor wafer having an oxide film, and forward scattered light is used when measuring a semiconductor wafer having a metal film. However, it is also possible to change the type of scattered light for measurement (forward scattered light, side scattered light, back scattered light) for measurement on other types of semiconductor wafers.

Further, not only φ and θ but also polarized light is P polarized light and S polarized light.
It is not limited to polarized light. It is also conceivable to change the polarization angle of the polarized light for measurement on other types of semiconductor wafers. In short, according to the foreign matter detecting apparatus of the present invention, various kinds of semiconductor wafers can be measured without being limited to the case where the semiconductor wafer has a mirror-finished semiconductor wafer, an oxide film, or a metal film.

Next, the incident angle of the irradiation light with respect to the semiconductor wafer will be described by taking the seventh embodiment of the present invention as an example. First, FIG. 11 is a schematic configuration diagram of a seventh embodiment of the present invention.
And the configuration of the present embodiment will be described in detail below. In this embodiment, a laser irradiation system 61, a scanning system 62, and a detection system 6
3 and a signal processing system 64.

The laser irradiation system 61 includes a laser oscillator 65 that outputs linearly polarized light, a beam expander 66, a polarizing beam splitter (hereinafter referred to as PBS) 67, a reflection mirror 68, and a condenser lens. And 69.

Here, the light beam emitted from the laser oscillator 65 is expanded by the beam expander 66, and is expanded by the PBS 67.
It is separated into polarized light and S polarized light. Laser spots 71 and 72 for both P-polarized light and S-polarized light are formed on the surface of the semiconductor wafer 70 by the reflecting mirrors 68 and the condenser lenses 69 and 69.
Are respectively collected as.

As shown in FIGS. 12 and 13, both the P-polarized light flux and the S-polarized light flux are incident on the surface of the semiconductor wafer 70 at an angle φ _{5 of} about 5 ° to about 20 °. Thus, the laser irradiation system 61 is set. At this time, both the P-polarized light flux and the S-polarized light flux are blocked from each other by the shutter 73 because they do not affect the detection.

The scanning system 62 includes a mounting table 74 on which the semiconductor wafer 70 is mounted, a θ table 75, and an X table 76.
It is composed of and. Since both the laser spots 71 and 72 of the P-polarized light flux and the S-polarized light flux are fixed, the entire surface of the semiconductor wafer 70 is scanned by the operation of the θ table 75 and the X table 76.
That is, the θ table 75 rotates at a predetermined speed, and the X table 76 linearly moves at a predetermined pitch, so that the entire surface of the semiconductor wafer 70 is spirally scanned. The shutter 73 is positioned between the detector 77 and the detector 78 even when the semiconductor wafer 70 is scanned.

The detection system 63 is a detector (first detector) 77.
And a detector (second detector) 78. The detectors 77 and 78 collect the scattered light generated from the semiconductor wafer 74 by the fiber plates 79 and 80, and detect the scattered light by the photomultiplier tubes 81 and 82. Here, the detector 77 is arranged so as to detect scattered light from the laser spot 71, and the detector 78 is arranged so as to detect scattered light from the laser spot 72.

As shown in FIG. 12, the detector 77 is arranged with the laser spot 71 formed by the P-polarized light beam at the center and φ ₆ with respect to the surface of the semiconductor wafer 70 at an angle of about 10 ° to about 50 °. Θ ₃ is arranged at an angle of about 70 ° to about 110 ° with respect to the laser incident surface by the light flux of.

On the other hand, as shown in FIG. 13, φ ₇ is arranged at an angle of about 10 ° to about 20 ° with respect to the surface of the semiconductor wafer 70 around the laser spot 72 formed by the S-polarized light beam, and Θ ₄ is arranged at an angle of about 115 ° to about 155 ° with respect to the laser incident surface.

The signal processing system 64 is composed of a hardware section and a software section. The hardware section amplifies the detected signal due to the scattered light from the semiconductor wafer 70 in order to increase the resolution of the signal in the interface circuit 84, and the A / D signal for this signal.
The interface circuit 84 for D-converting and fetching the result into the computer 85, and the computer 85. Software department is computer 8
It is constituted by a data processing program for arithmetically processing the signal (digital value) by the scattered light taken in 5 and determining the presence / absence of a foreign substance, the position of the foreign substance, and the size of the foreign substance. The computer 85 also controls the scanning system 62 by a control unit (not shown).

The operation of this embodiment is as follows. First, the laser light emitted from the laser oscillator 65 is the PBS 6
7, the light beam is divided into a P-polarized light beam and an S-polarized light beam, and the angle φ ₅ is about 5 ° to about 5 ° with respect to the surface of the semiconductor wafer 70 which is the object to be inspected by the reflection mirrors 68 and the condenser lenses 69. The laser spot 7 is incident at an angle of 20 °.
1.72 is formed.

Here, the reason why φ ₅ is an angle of approximately 5 ° to approximately 20 ° is that the minute roughness (surface roughness) generated on the surface of the semiconductor wafer 70 even from the surface of the semiconductor wafer 70 in which no foreign matter exists. This is because scattered light is generated by This is detected as a noise component (noise). In order to suppress this noise component and improve the S / N, the incident angle φ ₅ of the laser beam is smaller than the incident angle φ _{5 of the} laser beam is large (about 60 ° to 80 ° with respect to the surface of the semiconductor wafer 70). Is small (5 ° with respect to the surface of the semiconductor wafer 70)
It is better to be about 20 °). A schematic diagram is shown in FIG.

On the other hand, the semiconductor wafer 70 is mounted on the mounting table 74, the θ table 75 rotates at a predetermined speed, and the X table 76 linearly moves at a predetermined pitch, so that the semiconductor wafer 70 is moved. The laser spots 71 and 72 scan the entire surface of the semiconductor wafer 70 in a spiral shape.

At this time, if a foreign substance exists on the irradiation surface of the laser spots 71 and 72, the laser beam is strongly scattered by the foreign substance. The scattered light generated in the laser spot 71 by the P-polarized light flux is detected by the detector 77, and the scattered light generated in the laser spot 72 by the S-polarized light flux is detected by the detector 78.

The signals by the scattered light detected in this way are photoelectrically converted by the photomultiplier tubes 81 and 82, and the detection signals are further amplified by the amplifier circuit 83, and are passed to the computer 85 via the interface circuit 84. It is captured.

Then, the size of the foreign matter is estimated from the intensity of the signal due to the scattered light after being processed by the data processing program,
The foreign substance existing position is calculated back from the scanning positions of the θ table 75 and the X table 76. By repeating such scanning, scattered light is detected while scanning the entire surface of the semiconductor wafer 70, and information such as the number of foreign matters adhering to the surface of the semiconductor wafer 70 and their positions and sizes can be obtained. .

At this time, when the thickness of the metal film formed on the surface of the semiconductor wafer 70 is about 400 nm, the diameter of the foreign matter adhering to the surface of the semiconductor wafer 70 is about 0.2 μm.
The foreign matter smaller than m is specified by the signal from the detector 77. Further, in this case, the foreign matter having a diameter of approximately 0.2 μm or more is specified by the signal from the detector 78.

In addition, when the surface of the semiconductor wafer 70 is a mirror surface or when an oxide film is formed on the surface of the semiconductor wafer 70, the diameter of the foreign matter adhering to the surface of the semiconductor wafer 70 is less than about 0.1 μm. Foreign matter is identified by a signal from the detector 77. Further, the diameter in this case is approximately 0.
The foreign matter of 1 μm or more is specified by the signal from the detector 78. Since the metal film has a larger surface roughness, the noise component is large and the S / N is low. Therefore, the diameter of the detectable foreign matter also becomes large.

Here, the reason for using the laser beam having the different polarization angle depending on the size of the foreign matter attached to the surface of the semiconductor wafer 70 will be described with reference to FIGS. 15 and 16. FIG. 15 shows a light interference phenomenon in a space on the surface of the inspection object when a laser is incident on the surface of the inspection object. The incident light is reflected by the surface of the object to be inspected, but at this time, the incident light and the reflected light interfere with each other, and the interference wave (interference light) is a standing wave in the interference region (hatched portion) shown in FIG. Therefore, if a foreign matter exists in the standing wave region, the foreign matter scatters the standing wave light. Since the scattered light intensity is proportional to the light intensity of the standing wave, the larger the light intensity of the standing wave, the easier the scattered light can be detected.

However, the light intensity of the standing wave (standing wave intensity)
Changes periodically as shown in FIG. 15 depending on the height from the surface of the inspection object (distance in the Z direction). This change in light intensity is enlarged and FIG. 15 shows an example in which a semiconductor wafer (Si wafer) having a mirror surface is irradiated with an Ar ⁺ laser (wavelength: 488 nm). From FIG. 16, the standing wave intensity due to the incidence of P-polarized light is strong in the region up to approximately 0.2 μm from the surface of the inspection object, and the S-polarized light is incident in the region higher than approximately 0.2 μm. It can be seen that the standing wave intensity due to is strong.

From these results, in the Si wafer having a mirror surface, the diameter of the foreign matter adhering to the surface of the wafer is about 0.
A foreign substance of less than 2 μm is specified by a signal of scattered light due to P-polarized light. Further, in this case, the foreign matter having a diameter of approximately 0.2 μm or more is specified by the signal of the scattered light due to the S-polarized light. The computer 85 selects the detection signal.

Even when a metal film is formed on the surface of the Si wafer or an oxide film is formed on the surface of the Si wafer, only the threshold value of the diameter of the foreign matter adhering to the surface of the wafer is different. There is no change in the work of determining whether the reference data is based on P-polarized light or S-polarized light depending on whether the diameter of the foreign matter exceeds or does not exceed this threshold value.

The laser used is not an Ar ⁺ laser but a He-Cd laser (wavelength: 442 nm) or a He-Ne laser (wavelength:
(633 nm) when using other types of laser, because the period of the standing wave intensity distribution that depends on the laser wavelength changes,
Although the threshold value of the diameter of the foreign matter is different, the processing itself does not change.

Here, when arranging the detectors, the angle arrangement as shown in FIGS. 12 and 13 is used as described above. The reason for this is that the scattered light depends on the size of the foreign matter to be detected. This is because the spatial distribution characteristics are different.

That is, when the diameter of the foreign substance is smaller than the above-mentioned threshold value, as shown in FIG. 12, the detector 81 makes φ around the surface of the semiconductor wafer 70 centering on the laser spot 71 by the P-polarized light beam. ₆ is arranged at an angle of about 10 ° to about 50 ° (near the surface), and θ ₃ is arranged at an angle of about 70 ° to about 110 ° (side scattering) with respect to the laser incident surface by the P-polarized light flux. Has been done. This is because scattered light is strongly generated in these directions.

On the other hand, as shown in FIG. 13, φ ₇ is arranged at an angle of about 10 ° to about 20 ° (near the reflected light) with respect to the surface of the semiconductor wafer 70 with the laser spot 72 formed by the S-polarized light beam as the center. (The incident angle φ ₅ is about 10 ° to about 20 °
Therefore, θ ₄ is arranged at an angle of about 115 ° to about 155 ° (forward scattering) with respect to the laser incident surface of the S-polarized light beam. This is also because scattered light is strongly generated in these directions.

Here, the lower limit of the size of the angles φ ₆ and φ ₇ is about 10 ° because the size of the detector is taken into consideration. If possible, a smaller angle (about It is preferable that the angle is about 5 °. The upper limit of the angle θ ₄ is about 155 ° in order to avoid specular reflection light, and ideally 180 ° is desirable.

Further, according to the data collected in this way, a detection intensity curve having a good linear characteristic can be obtained as shown in FIG. 17, so that the particle size of the foreign matter can be accurately determined from the detection intensity curve. This will be described with reference to FIG. Figure 1
8 (a) shows that there are foreign matters having a diameter of 0.1 μm (foreign matter A), 0.4 μm (foreign matter B), and 0.6 μm (foreign matter C) on the surface of the inspection object. ing.

As a result of scanning the laser spot, FIG. 18B shows a scattered light signal due to incidence of P-polarized light detected by the detector 77, and FIG. 18C shows detection by the detector 78. The scattered light signal by incidence of S polarization is shown. Figure 1
8 (b) and FIG. 18 (c), a signal A is used to detect a foreign substance having a diameter of 0.1 μm, but a signal B and a signal C are used to detect a foreign substance having a diameter of 0.4 μm and a diameter of 0.6 μm, respectively.
It is understood that it is better to use the signal B ′ and the signal C ′, respectively, instead of using (see FIG. 18D).

The above is summarized in the following [Table 2].

[0103]

[Table 2]

As is the case with all of the above embodiments, other types of lasers such as a He-Cd laser (wavelength: 442 nm) and a He-Ne laser (wavelength: 633 nm) may be used instead of the Ar ⁺ laser. -Z can also be used. Instead of using a laser that outputs linearly polarized light, a polarizer that outputs random polarized light may be combined with a polarizer to generate P-polarized light or S-polarized light. The light receiving element is a photomultiplier tube 33.
Instead of 57.59.81.82, a semiconductor photosensor or the like may be used. In addition, although the semiconductor wafer is taken as an example of the object to be inspected, the object to be inspected is not limited to this, and a liquid crystal substrate or one having a curved surface portion can be used for the foreign matter inspection apparatus of the present invention.

The reason for this is that even if it is a curved surface when viewed macroscopically, it becomes a plane when viewed microscopically.
This is because the curved surface to be inspected can be inspected like a plane by reducing the spot diameters of 71 and 72.

[0106]

According to the present invention, it is possible to increase the detection sensitivity of foreign matter, and detect foreign matter of 0.1 μm or less in a semiconductor wafer having a mirror surface or a semiconductor wafer having an oxide film, and a semiconductor having a metal film. It is possible to provide a foreign matter inspection device and a foreign matter inspection method that can reliably detect foreign matter of 0.2 μm or less on a wafer.

Further, according to the present invention, it is possible to improve the foreign matter detection sensitivity and the linear characteristic of the foreign matter detection signal, and suppress the influence of the noise component from the surface of the object to be inspected to detect the foreign matter with a good linear characteristic. It is possible to provide a foreign matter inspection device and a foreign matter inspection method that can be performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a foreign matter inspection device according to a first embodiment of the present invention.

FIG. 2 is a side view showing a positional relationship between a fiber plate and a photomultiplier tube and a semiconductor wafer in the foreign matter inspection apparatus according to the first embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the arrangement angle of the light receiving system and the intensity of scattered light in the foreign matter inspection apparatus according to the first embodiment of the present invention.

FIG. 4 is a graph showing the arrangement angle of the light receiving system and the S / N of the foreign matter detection signal in the foreign matter inspection apparatus according to the first embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a foreign matter inspection device according to a fourth embodiment of the present invention.

FIG. 6 is a schematic diagram showing a positional relationship among detectors, a laser incident surface, and a semiconductor wafer in a foreign matter inspection apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a flowchart showing a flow of processing for selecting a polarization state and a detector depending on the type of a semiconductor wafer (inspection object) in the foreign matter inspection apparatus according to the fourth embodiment of the present invention.

FIG. 8 is a graph showing the arrangement angle of the detector and the S / N of the foreign matter detection signal when the mirror surface wafer is measured by the foreign matter inspection apparatus according to the fourth embodiment of the present invention.

FIG. 9 is a graph showing the arrangement angle of the detector and the S / N of the foreign matter detection signal when the wafer with an oxide film is measured by the foreign matter inspection apparatus according to the fourth embodiment of the present invention.

FIG. 10 is a graph showing the arrangement angle of the detector and the S / N of the foreign matter detection signal when the wafer with metal film is measured by the foreign matter inspection apparatus according to the fourth embodiment of the present invention.

FIG. 11 is a schematic configuration diagram showing a foreign matter inspection device according to a seventh embodiment of the present invention.

FIG. 12 is a schematic diagram (1) showing the positional relationship among the detector, the laser incident surface, and the semiconductor wafer in the foreign matter inspection apparatus of the seventh embodiment of the present invention.

FIG. 13 is a schematic view (2) showing the positional relationship among the detector, the laser incident surface, and the semiconductor wafer in the foreign matter inspection apparatus of the seventh embodiment of the present invention.

FIG. 14 is a graph showing the relationship between the intensity of scattered light and the inspection time when the incident angle of laser light is large and when the incident angle of laser light is small in the foreign matter inspection apparatus according to the first embodiment of the present invention.

FIG. 15 is a schematic diagram showing interference of light by incident light and reflected light on the surface of a semiconductor wafer.

FIG. 16 is a graph showing the relationship between the distribution of standing wave intensity on the surface of a semiconductor wafer and the diameter of a foreign substance.

FIG. 17 is a graph showing the diameter of a foreign substance, the intensity of scattered light, and the selection of a detector in the foreign substance inspection apparatus according to the seventh embodiment of the present invention.

FIG. 18 (a) is a schematic view showing the sizes of the foreign matters A to C in the foreign matter inspection apparatus of the seventh embodiment of the present invention,
(B) is a graph showing the relationship between the output signal of the first detector and the inspection time for foreign matter A to foreign matter C, and (c) is the foreign matter A
To a graph showing the relationship between the output signal of the second detector and the inspection time for the foreign matter C, and (d) a graph showing the relationship between the foreign matter detection result for the foreign matter A to the foreign matter C and the inspection time.

FIG. 19 is a schematic configuration diagram showing a foreign matter inspection apparatus of a first conventional example.

FIG. 20 is a schematic configuration diagram showing a foreign matter inspection device of a second conventional example.

FIG. 21 is a schematic configuration diagram showing a foreign matter inspection device of a third conventional example.

FIG. 22 is a side view showing a positional relationship between a line sensor and a semiconductor wafer in a foreign matter inspection apparatus of a fourth conventional example.

FIG. 23 is a schematic configuration diagram showing a foreign matter inspection apparatus of a fifth conventional example.

FIG. 24 is a graph showing the relationship between the diameter of a foreign substance and the intensity of scattered light in a conventional foreign substance inspection device.

[Explanation of symbols]

 1.26.51.74 ... Mounting table 2.46.70 ... Semiconductor wafer 3.27.41.65 ... Laser oscillator 4.66 ... Collimating lens 5 ... Galvano mirror 6.14.16.22 ... Focusing Optical system 7 ... Line sensor 8, 9, 13, 17 ... Light receiving element 10, 18 ... Measuring circuit 11 ... XY table 12 ... Container 15 ... Half mirror 19 ... XY table controller 20 ... XYθ table 21, 29.44 ... Reflection Mirror 23/35 Detecting unit 24/52/75 θ table 25/53/76 X table 28/43 1/2 Wave plate 30/45/69 Condensing lens 31/47/71/72 Laser Spot 32.56.58.79.80 ... Fiber plate 33.57.59.81.82 ... Photomultiplier tube 34 ... Amplifying unit 36.61 ... Laser irradiation system 37 ... Control system 38・ 62 ... Scanning system 39.63 ... Detection system 40.64 ... Signal processing system 42.66 ... Beam expander 48 ... Control circuit 49.85 ... Computer 50.84 ... Interface circuit 54.55.77.78 ... Detector 60/83 ... Amplifying circuit 67 ... Polarizing beam splitter 68 ... Reflecting mirror 73 ... Shutter

Claims (16)

[Claims] 1. A foreign matter inspection apparatus for inspecting fine foreign matter on the surface of an object to be inspected, wherein a light source and a P emitted from this light source.
Condensing means for condensing only the polarization component on the surface of the object to be inspected, scanning means for relatively scanning the surface of the object to be inspected with the spot light condensed by the light condensing means, and scanning means for this. A light receiving means for directly receiving the light scattered from the irradiation position of the spot light scanned by, and a detecting means for detecting foreign matter on the surface of the object to be inspected based on the intensity of light received by the light receiving means. Foreign matter inspection device. 2. The foreign matter inspection apparatus according to claim 1, wherein the light receiving means is about 5 degrees to about 40 degrees with respect to the surface of the inspection object with reference to the irradiation position of the spot light scanned by the scanning means. The foreign matter inspection device is characterized by receiving light scattered at an angle of. 3. A foreign matter inspection device for inspecting fine foreign matter on the surface of an object to be inspected, the light source, and S emitted from this light source.
Condensing means for condensing only the polarization component on the surface of the object to be inspected, scanning means for relatively scanning the surface of the object to be inspected with the spot light condensed by the light condensing means, and scanning means for this. A light receiving means for directly receiving the light scattered from the irradiation position of the spot light scanned by, and a detecting means for detecting foreign matter on the surface of the object to be inspected based on the intensity of light received by the light receiving means. Foreign matter inspection device. 4. The foreign matter inspection apparatus according to claim 3, wherein the light receiving means is approximately 65 degrees to approximately 90 degrees with respect to the surface of the inspection object with reference to the irradiation position of the spot light scanned by the scanning means. The foreign matter inspection device is characterized by receiving light scattered at an angle of. 5. A foreign matter inspection apparatus comprising the foreign matter inspection apparatus according to claim 1 and the foreign matter inspection apparatus according to claim 3 together. 6. The foreign matter inspection apparatus according to claim 1, 3 or 5, wherein the condensing means is provided on the surface of the object to be inspected with reference to the irradiation position of the spot light scanned by the scanning means. On the other hand, a foreign matter inspection apparatus, which collects light emitted from the light source at an angle of approximately 5 degrees to approximately 20 degrees. 7. A foreign matter inspecting apparatus for inspecting fine foreign matter on the surface of an object to be inspected, comprising: a light source; and a polarization component varying means for varying the polarization angle of the light emitted from the light source according to the type of the object to be inspected. A condensing means for condensing the light emitted from the polarization component varying means on the surface of the object to be inspected in a spot shape, and the spot light condensed by the light condensing means relatively scans the surface of the object to be inspected. Scanning means, a light receiving means for directly receiving the light scattered from the irradiation position of the spot light scanned by the scanning means, and a detecting means for detecting a foreign substance or the like on the surface of the object to be inspected based on the intensity of light received by the light receiving means. And a foreign matter inspection device. 8. The foreign matter inspection apparatus according to claim 7, wherein the light converging means is approximately 5 degrees to approximately 20 degrees with respect to the surface of the inspected object with reference to the irradiation position of the spot light scanned by the scanning means. A foreign matter inspection apparatus, which collects light emitted from the polarization changing means at an angle of degrees. 9. The foreign matter inspection apparatus according to claim 1, claim 3, claim 5, or claim 7, with respect to the surface of the object to be inspected with reference to the irradiation position of the spot light scanned by the scanning means. Light scattered at a predetermined angle by
The foreign matter inspection apparatus, wherein the light receiving means moved by the moving means of the light receiving means receives light. 10. A foreign matter inspection apparatus for inspecting fine foreign matter on the surface of an object to be inspected, a light source, a polarization component separating means for separating light emitted from this light source into a P-polarized component and an S-polarized component, and this polarized light. A first condensing unit and a second condensing unit that condense the P-polarized component and the S-polarized component of the light separated by the component separating unit on the surface of the object to be inspected, respectively, and the first condensing unit. Scanning means for relatively scanning the surface of the object to be inspected with the first spot light and the second spot light condensed by the light means and the second condensing means, and the scanning means for scanning by the scanning means. First light receiving means and second light receiving means for directly receiving the light scattered from the irradiation positions of the first spot light and the second spot light respectively, and the first light receiving means and the second light receiving means 1 received light intensity and 2
And a detection means for detecting foreign matter on the surface of the object to be inspected based on the first received light intensity or the second received light intensity selected by the selecting means. Foreign matter inspection device characterized by: 11. The foreign matter inspection apparatus according to claim 10, wherein the first light receiving means is substantially on the surface of the object to be inspected with reference to the irradiation position of the first spot light scanned by the scanning means. The second light receiving means receives the light scattered at an angle of 5 degrees to about 50 degrees, and the second light receiving means is based on an irradiation position of the second spot light scanned by the scanning means. About 5 for body surface
A foreign matter inspection device, which receives light scattered at an angle of approximately 20 degrees to approximately 20 degrees. 12. The foreign matter inspection apparatus according to claim 10, wherein the first condensing unit and the second condensing unit are based on an irradiation position of the spot light scanned by the scanning unit. About 5 degrees to about 20 to the body surface
A foreign matter inspection apparatus, which collects light emitted from the polarization component separating means at an angle of degrees. 13. A foreign matter inspection method for inspecting fine foreign matter on a surface of an inspected object, a light projecting step of irradiating the surface of the inspected object with inspection light, and only the P-polarized component of the inspection light. Condensing step of condensing in a spot-like shape, a scanning step of relatively scanning the surface of the inspected object with the spot light condensed in this condensing step, and irradiation of the spot light scanned in this scanning step. A foreign matter characterized by comprising a light receiving step of directly receiving light scattered from a position by a light receiving means, and a detecting step of detecting a foreign matter or the like on the surface of the object to be inspected based on the light receiving intensity obtained in the light receiving step. Inspection method. 14. A foreign matter inspecting method for inspecting fine foreign matter on a surface of an object to be inspected, a light projecting step of irradiating the surface of the object to be inspected with inspection light, and the S-polarized component of the inspection light alone. Condensing step of condensing in a spot-like shape, a scanning step of relatively scanning the surface of the inspected object with the spot light condensed in this condensing step, and irradiation of the spot light scanned in this scanning step. A foreign matter characterized by comprising a light receiving step of directly receiving light scattered from a position by a light receiving means, and a detecting step of detecting a foreign matter or the like on the surface of the object to be inspected based on the light receiving intensity obtained in the light receiving step. Inspection method. 15. A foreign matter inspection method for inspecting fine foreign matter on the surface of an inspected object, the step of projecting the inspection light onto the surface of the inspected object, and polarization of the inspected light according to the type of the inspected object. A polarization component varying step of varying the angle, a converging step of concentrating the inspection light, which has been polarized in a predetermined manner in the polarization component varying step, on the surface of the object to be inspected, and a condensing step A scanning step of relatively scanning the surface of the inspected object with the spotted light, a light receiving step of directly receiving the light scattered from the irradiation position of the spot light scanned in the scanning step by a light receiving means, and this light receiving step And a detection step of detecting a foreign matter or the like on the surface of the object to be inspected based on the received light intensity obtained in step 1. 16. A foreign matter inspection method for inspecting fine foreign matter on the surface of an inspected object, the step of projecting light for inspecting the surface of the inspected object, and separating this inspection light into a P-polarized component and an S-polarized component. And a first converging step of converging the P-polarized component and the S-polarized component of the light separated in the polarized component separating step into spots on the surface of the object to be inspected. Condensing step, and scanning step of relatively scanning the surface of the object to be inspected with the first spot light and the second spot light collected by the first and second condensing steps. And the first scanned by this scanning process
First light receiving step of directly receiving the light scattered from the irradiation positions of the second spot light and the second spot light, and the second light receiving step
Light receiving step, a selection step of selecting the first light receiving intensity and the second light receiving intensity by the first light receiving step and the second light receiving step, and the first light receiving intensity selected by this selecting step. Or a detection step of detecting foreign matter or the like on the surface of the object to be inspected based on the second received light intensity.