JP3348198B2 - Evaluation surface roughness measurement method and evaluation surface roughness measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaluation surface roughness measuring method capable of individually obtaining "surface roughness" and "correlation distance" indicating the roughness of an evaluation surface of a sample, and a method for implementing the method. The present invention relates to an apparatus for measuring roughness of an evaluation surface.

[0002]

2. Description of the Related Art Conventionally, when measuring the roughness of an evaluation surface, a probe is brought close to the evaluation surface, a three-dimensional shape is actually measured, and the roughness of the evaluation surface is expressed based on the data of the three-dimensional shape.
The two parameters, surface roughness (the square root of the root mean square of the height of the unevenness of the evaluation surface) and the correlation distance (the magnitude of the correlation is e
^-1 ).

[0003]

However, if the surface roughness and the correlation distance are calculated from the data actually measured by the three-dimensional shape measuring apparatus as in the prior art, the roughness of the evaluation surface can be obtained with high accuracy, but the cost is high. In addition, since it takes a relatively long time to actually measure the three-dimensional shape, it is not suitable for applications requiring 100% inspection. For example, when evaluating a magnetic recording surface of a hard disk or the like in which irregularities of about 0.1 μm (less than the wavelength of light) are a problem, it is desirable to be able to perform 100% inspection in a short time, and it is an index of roughness of the evaluation surface. There is a need for a method and apparatus that can efficiently measure only the parameters of “surface roughness” and “correlation distance” in a short time.

[0004]

According to a first aspect of the present invention, there is provided a method for measuring the roughness of an evaluation surface, comprising the steps of: When irradiating the electromagnetic wave of, according to the incident angle θ ₀ and the relative refractive index n of the dielectric with respect to the electromagnetic wave irradiation side medium, the scattering Brewster angle Θ _B1 in the electromagnetic wave irradiation side medium,

(Equation 5) Under the conditions that satisfy the condition, the correlation distance of the evaluation plane is calculated based on the ratio of the intensity of the S-polarized component to the intensity of the P-polarized component of the scattered wave obtained at the scattering Brewster angle Θ _B1 . Features.

According to a second aspect of the present invention, there is provided a method for measuring roughness of an evaluation surface according to the first aspect, wherein the scattering Brewster angle Θ _B1
The surface roughness of the evaluation surface is obtained based on the correlation distance obtained based on the ratio of the intensity of the S-polarized component to the intensity of the P-polarized component of the scattered wave obtained in the above, and the electromagnetic wave scattering intensity from the sample surface. It is characterized by doing so.

According to a third aspect of the present invention, there is provided a method for measuring the roughness of an evaluation surface, the method comprising: when irradiating a P-polarized electromagnetic wave to an evaluation surface of a dielectric, which is a sample for measuring the roughness of the evaluation surface; _{According to 0} and the relative refractive index n of the dielectric with respect to the electromagnetic wave irradiation side medium,
The scattered Brewster angle に お け る ' _B2 on the dielectric side where the electromagnetic wave enters is

(Equation 6) The correlation distance of the evaluation plane is determined based on the ratio of the intensity of the S-polarized component to the intensity of the P-polarized component of the scattered wave obtained at the scattered Brewster angle Θ ′ _B2 under the condition satisfying It is characterized by.

According to a fourth aspect of the present invention, in the method for measuring the roughness of the evaluation surface according to the third aspect, the scattering Brewster angle Θ '
A correlation distance obtained based on the ratio of the intensity of the S-polarized component to the intensity of the P-polarized component of the scattered wave obtained in _B2 ,
It is characterized in that the surface roughness of the evaluation surface is determined based on the intensity of electromagnetic wave scattering inside the sample.

According to a fifth aspect of the present invention, there is provided an apparatus for measuring roughness of an evaluation surface, comprising: an electromagnetic wave irradiation means for irradiating a P-polarized electromagnetic wave to an evaluation surface of a dielectric (22) which is a sample for measuring the roughness of the evaluation surface. 2
1) and the scattering Brewster angle Θ _B1 of the electromagnetic wave irradiation side medium according to the incident angle θ ₀ of the electromagnetic wave irradiated from the electromagnetic wave irradiation means and the relative refractive index n of the dielectric with respect to the electromagnetic wave irradiation side medium,

(Equation 7) The first scattered wave obtaining means (2) for obtaining the S-polarized component of the scattered wave at the scattered Brewster angle Θ _B1 under the condition satisfying
4), a second scattered wave obtaining means (25) for obtaining the P-polarized component of the scattered wave at the scattered Brewster angle Θ _B1 , and the intensity of the P-polarized component obtained by the second scattered wave obtaining means and the second And a roughness calculating means (26) for calculating a correlation distance of the evaluation surface based on a ratio of the intensity of the S-polarized component acquired by the one scattered wave acquiring means.

According to a sixth aspect of the present invention, in the apparatus for measuring the roughness of the evaluation surface, the roughness calculating means determines the roughness based on a ratio of the intensity of the S-polarized component to the intensity of the P-polarized component. The surface roughness of the evaluation surface is calculated based on the calculated correlation distance and the intensity of electromagnetic wave scattering from the sample surface.

According to a seventh aspect of the present invention, there is provided an evaluation surface roughness measuring device for irradiating a P-polarized electromagnetic wave to an evaluation surface of a dielectric (32) which is a sample of the evaluation surface roughness measurement. 3
1) and the scattering Brewster angle Θ ′ _B2 on the dielectric side where the electromagnetic wave is incident is determined according to the incident angle θ ₀ of the electromagnetic wave emitted from the electromagnetic wave irradiating means and the relative refractive index n of the dielectric with respect to the electromagnetic wave irradiation side medium. ,

(Equation 8) The first scattered wave obtaining means (3) for obtaining the S-polarized component of the scattered wave at the scattered Brewster angle Θ ' _B2 under the condition
4) and the P of the scattered wave at the scattered Brewster angle Θ ' _B2
A second scattered wave obtaining means (35) for obtaining a polarized wave component, the intensity of the P polarized light component obtained by the second scattered wave obtaining means, and the intensity of the S polarized light component obtained by the first scattered wave obtaining means. And a roughness calculating means (36) for calculating the correlation distance of the evaluation surface based on the ratio of

According to an eighth aspect of the present invention, in the above-described seventh aspect, the roughness calculating means determines the roughness based on a ratio of the intensity of the S-polarized component to the intensity of the P-polarized component. The surface roughness of the evaluation surface is calculated based on the correlation distance and the intensity of scattering of electromagnetic waves into the sample.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method for measuring roughness of an evaluation surface according to the present invention and an apparatus for measuring roughness of an evaluation surface capable of realizing the method will be described with reference to the accompanying drawings. Prior to that, the principle and outline of a method and an apparatus proposed by the inventor of the present invention in Japanese Patent Application No. 10-267451 which can evaluate the surface of a dielectric without contact will be described.

As shown in FIG. 1, when a transparent sample is irradiated with light at an incident angle θ ₀ from the air, if the roughness of the irradiated surface is small, the scattered wave reflected on the incident side medium (air) is reduced. And the transmitted wave transmitted through the transmission side medium (translucent sample) have a scattered Brewster angle Θ _B1 and a scattered Brewster angle Θ ' _{B2 in} which the P polarization component of the scattered light is equal to zero.

[0014]

(Equation 9)

[0015]

(Equation 10)

In the above two equations, n is a relative refractive index of the sample to air. Such a phenomenon is observed, for example, when an electromagnetic wave is irradiated on a dielectric surface having a minute irregular structure. Since the transmission and non-transmission of the sample differs depending on the wavelength and intensity of the electromagnetic wave, the above-described properties may be exhibited even if the dielectric is opaque in the visible light region.

Further, light irradiation and scattering are three-dimensionally grasped.
In Fig. 1, light is applied to the sample for simplicity.
Irradiation in a plane perpendicular to the irradiation surface of
Wuster angleΘ_B1And the scattering Brewster angle Θ '_B2Also the same
It appears in the plane. In other words, how light enters
Azimuth (φ_S) Is the scattering Brewster angle Θ _B1
At_S= 0, scattering Brewster angle Θ '_B2In
And φ_s= 180 °.

Here, the scattered waves generally have first, second, and third order.
It is possible to consider components such as the following,..., The primary scattering intensity becomes the square of the surface roughness, the secondary becomes the fourth power,
Since the third order depends on the sixth power, the first-order scattering is dominant when the surface roughness is small, and the high-order scattering is dominant when the surface unevenness is remarkable (when the roughness is large). It has the property of becoming a target. Then, the scattering Brewster angle theta _B1, 1-order scattering intensity P polarization component is zero.

Accordingly, when a sample having a small surface roughness is irradiated with an electromagnetic wave, the primary scattering is predominant in the nature of the scattered wave, and the P polarization component of the scattered light at the scattered Brewster angle Θ _B1 is significantly reduced. When a sample with a rough surface is irradiated with electromagnetic waves, higher-order scattering becomes dominant and the scattering Brewster angle Θ
The decrease in the P polarization component of the scattered light at _B1 becomes inconspicuous. Similarly, when a sample with a small surface roughness is irradiated with an electromagnetic wave, the first-order scattering becomes dominant in the nature of the scattered wave scattered to the scattered Brewster angle Θ ′ _B2 , and the P-polarized component of the scattered light When a sample having a rough surface is irradiated with an electromagnetic wave, the property of the scattered wave scattered to the scattered Brewster angle Θ ′ _B2 is also dominated by higher-order scattering, and the P of the scattered light becomes higher.
The decrease in the polarization component becomes inconspicuous.

That is, when the roughness of the electromagnetic wave irradiation surface is small, the S-polarized component of the scattered wave from the sample surface changes smoothly in the scattering intensity distribution as shown in FIG. As shown in FIG. 2B, when the scattering angle θ _S is equal to the scattering Brewster angle Θ _{B 1} , the P polarization component disappears. On the other hand, when the electromagnetic wave irradiation surface is rough,
Both the S polarization component and the P polarization component show a scattering intensity distribution as shown in FIG. 3, and the P polarization component does not disappear even at the scattering Brewster angle 散乱_B1 . This property is also found in the scattered light to the scattered Brewster angle Θ ′ _B2 .

Therefore, the above-mentioned scattering Brewster angle し た_B1
Alternatively, utilizing the universal phenomenon that the P-polarized component of the scattering intensity to the scattering Brewster angle Θ ′ _B2 changes according to the roughness of the dielectric surface, it is versatile without depending on the measurement target. It is possible to perform stable evaluation of the surface roughness.

As a first evaluation method utilizing the characteristics of the P-polarized component, an electromagnetic wave including an S-polarized component and a P-polarized component is radiated to an evaluation surface of a dielectric, and a scattering Brewster is used. The S polarization component and the P polarization component are respectively obtained from the scattered light to the angle Θ _B1 or the scattering Brewster angle Θ ′ _B2 , and the degree of reduction of the P polarization component is determined by the S polarization component and the P polarization component. There is a method of judging from the ratio. That is, the surface roughness of the evaluation surface is evaluated based on the property that the lower the ratio of the P polarization component is, the smaller the surface roughness is, and conversely, the higher the ratio of the P polarization component is, the higher the surface roughness is. is there.

FIG. 4 shows a non-contact surface roughness evaluation device which embodies the first evaluation method, and which converts a laser beam (electromagnetic wave including S-polarized wave and P-polarized wave) polarized at 45 degrees. A laser light source 1 as an electromagnetic wave irradiating means for irradiating, a polarizing beam splitter 3 arranged to receive scattered light of a laser radiated from the laser light source 1 onto a surface of a sample 2 at a scatter Brewster angle Θ _B1 ; A first photodetector 4 as first scattered wave obtaining means for obtaining the S polarization component separated by the polarization beam splitter 3, and a second photodetector 4 for obtaining the P polarization component separated by the polarization beam splitter 3; A second photodetector 5 as scattered wave acquisition means,
The computer 6 determines the roughness of the evaluation surface of the sample 2 based on the S-polarized component and the P-polarized component obtained from the photodetectors 4 and 5.

In the determination by the computer 6, data serving as an evaluation criterion is stored in advance, and the surface is evaluated based on the ratio between the S-polarization component and the P-polarization component obtained at the time of evaluation based on this data. is there.

Further, a second method utilizing the characteristics of the P polarization component
As an evaluation method, electromagnetic waves containing only P-polarized
Irradiation on the evaluation surface of the body, scattering Brewster angle Θ_B1Or
Scattering Brewster angle Θ '_B2And the scattering intensity of the scattered light
Scattering Brewster angle_B1And scattering Brewster angle
Θ ′_B2Direction (evaluation reference angle θ₁) Scattered light scattering
And the scattered Brewster angle Θ_B1Smell
Degree of reduction of P polarization component or scattering Brewster
Angle Θ '_B2The degree of reduction of the P polarization component at
Degree ratio ("θ₁: Θ_B1Or “θ₁: Θ '_B2")
Is determined. That is, scattering bruss
TA angle Θ_B1Or scattering Brewster angle Θ ' _B2Scattered in
The lower the ratio of the turbulence intensity, the smaller the surface roughness, and conversely the scattering
Brewster angleΘ_B1Or scattering Brewster angle Θ '_B2
The higher the ratio of the scattering intensity at the surface, the greater the surface roughness
Based on this property, the roughness of the evaluation surface is evaluated.
You.

FIG. 5 shows a non-contact surface roughness evaluation apparatus which embodies the second evaluation method, and includes a laser light source 11 as an electromagnetic wave irradiation means for irradiating an electromagnetic wave mainly composed of P-polarized light. The scattered light of the laser radiated from the laser light source 11 to the surface of the sample 12 is scattered by the Brewster angle Θ _B1.
A third light detector 13 serving as first scattering intensity detection means arranged to detect scattering intensity at an evaluation reference angle θ ₁ different from the laser light emitted from the laser light source 11 to the surface of the sample 12. A fourth photodetector 14 arranged to receive the scattered light at the scatter Brewster angle Θ _B1 , a scattered intensity and a scatter Brew at the evaluation reference angle θ ₁ detected by the third and fourth photodetectors 13 and 14. consisting determines computer 15. the roughness of the evaluation surface of the specimen 12 on the basis of the scattering intensity in the static angle theta _B1.

In the determination by the computer 15, data serving as an evaluation reference is stored in advance, and the scattering intensity at the evaluation reference angle θ _{1 and} the scattering intensity at the scattering Brewster angle Θ _B1 acquired at the time of evaluation based on this data. The surface is evaluated from the ratio.

However, in the surface evaluation based on the scattering Brewster angle Θ _B1 as described above, the sample surface is evaluated based only on “surface roughness” which is one of two parameters in the roughness measurement of the evaluation surface. And the other parameter “correlation distance” cannot be measured. That is, it is not possible to measure the two parameters required for measuring the roughness of the evaluation surface.

Therefore, in the present invention, there is provided a method capable of individually measuring the surface roughness and the correlation distance by utilizing the characteristics of the scattered wave to the scattered Brewster angle Θ _B1 and an apparatus capable of realizing the method. To do. Hereinafter, the principle and embodiments will be described in detail.

First, on the evaluation surface having a small surface roughness,
The phenomenon that the P polarization component becomes zero at the scattering Brewster angle Θ _B1 occurs because the characteristic of the primary scattering becomes dominant as described above. However, strictly speaking, it is necessary to consider the effect of higher-order scattering (multiple scattering), so that a co-polarization component (a component of the same polarization as the polarization of the incident wave: P-polarization) and a cross-polarization component (incident polarization) The component of the polarization orthogonal to the polarization of the wave: S-polarization) is detected. Then, as a property of the secondary scattering, the scattering Brewster angle 立 つ_B1 that satisfies the above-described relational expression 9
The intensity of the co-polarized component and the intensity of the cross-polarized component obtained in step (a) vary according to the surface roughness and the correlation distance, but the ratio of the intensity of the co-polarized component to the intensity of the cross-polarized component is It is almost constant without depending on the size. This is shown in FIG.
It is a characteristic-curve figure of (a) and FIG.6 (b).

FIGS. 6A and 6B show that the light of the P-polarized component is applied to the sample surface in an environment where the relative refractive index n between the sample to be evaluated and the light incident side medium is 1.51. This is a numerical simulation of scattering when irradiated. The horizontal axis in each figure is the scattering angle, and the vertical axis is the ratio (S / P) of the intensity of the S polarization component to the intensity of the P polarization component. Also, l
Is the correlation distance, σ is the surface roughness, and k is the wave number of the incident wave.

FIG. 6 shows that the correlation distance 1 is 2.0 / k
And the surface roughness σ is 0.05 / k, 0.1 / k,
Each characteristic is shown when the ratio is changed to 0.3 / k and 0.5 / k. At the scattering Brewster angle (Θ _B1 = 53.3 degrees), it does not depend on the value of the surface roughness σ. , S / P are constant. On the other hand, FIG. 7 shows that the surface roughness σ is 0.1
/ K, and the correlation distance 1 is 2.0 / k, 3.0 /
k, 4.0 / k and 8.0 / k are shown, and at the scattering Brewster angle (Θ _B1 = 53.3 degrees), S / P is changed according to the correlation distance l. Have different values.

That is, in the scattered wave obtained in the direction of the scattered Brewster angle Θ _B1 , the ratio (for example, S / P) of the co-polarized component and the cross-polarized component depends only on the correlation distance l, and the surface roughness That is, a phenomenon that does not depend on the magnitude σ occurs.

Therefore, the sample having a small surface roughness such that the primary scattering becomes dominant and the decrease of the P-polarized component of the scattered light at the scattering Brewster angle Θ _B1 becomes remarkable is applied to the electromagnetic wave of the P-polarized component. And the P-polarized component and the S-polarized component are acquired at the scattering Brewster angle Θ _B1 , the correlation between the evaluation plane and the intensity of the P-polarized component and the S-polarized component is obtained. The distance can be measured directly.

Incidentally, measurable data such as the scattering intensity generally depends on both parameters of the surface roughness and the correlation distance. Therefore, if the correlation distance is determined as described above, the data is based on the electromagnetic wave scattering intensity from the sample surface. To determine the surface roughness. That is, since the scattering intensity is determined based on the relationship between the correlation distance and the surface roughness, if the correlation distance is specified from the combination of the surface roughness and the correlation distance for obtaining the measured scattering intensity, it is inevitable. The surface roughness can also be specified. Specifically, a reference table including a combination of “scattering intensity”, “surface roughness”, and “correlation distance” is prepared in advance, and a table satisfying the condition may be extracted from the table. Thus, according to the method for measuring the roughness of the evaluation surface according to the present invention, two parameters indicating the roughness of the evaluation surface, that is, “surface roughness” and “correlation distance” can be individually obtained, It is possible to substantially measure the roughness of the evaluation surface.

FIG. 7 shows the scattering Brewster angle Θ _B1
Embodiment 1 of a roughness measuring apparatus for an evaluation surface embodying a method for measuring the roughness of an evaluation surface using scattered waves to a laser as an electromagnetic wave irradiation means for irradiating an electromagnetic wave containing only a P polarization component A light source 21, a polarization beam splitter 23 arranged to receive the scattered light of the laser radiated from the laser light source 21 to the surface of the sample 22 at a scattering Brewster angle Θ _B1 , and separated by the polarization beam splitter 23. The first photodetector 24 as a first scattered wave obtaining means for obtaining the S-polarized component, and the second photodetector 24 as a second scattered wave obtaining means for obtaining the P-polarized component separated by the polarization beam splitter 23. The correlation distance between the evaluation plane of the sample 22 and the photodetector 25 is determined based on the ratio between the intensity of the P polarization component and the intensity of the S polarization component acquired from the first and second photodetectors 24 and 25. And more A computer 26 as a roughness calculation means for obtaining a surface roughness on the basis of the electromagnetic scattering intensity from Seki distance and the sample 22 surface, made of.

In the calculation of the correlation distance and the surface roughness by the computer 26, an approximate calculation formula stored in advance may be used, or a comparison table corresponding to the material to be evaluated may be used. Is also good. Further, the electromagnetic wave scattering intensity from the sample surface required for obtaining the surface roughness may use the value measured when obtaining the correlation distance, or may be measured separately from this. .

Note that the ratio of the co-polarized component to the cross-polarized component (for example, S / P) of the scattered wave obtained in the direction of the scattered Brewster angle Θ ′ _B2 also depends only on the correlation distance l. There occurs a phenomenon that it does not depend on the roughness σ. Therefore, the sample having a small surface roughness is irradiated with the electromagnetic wave of the P polarization component to such an extent that the primary scattering becomes dominant and the reduction of the P polarization component of the scattered light at the scattering Brewster angle Θ ′ _B2 becomes remarkable. Then, if the P polarization component and the S polarization component are obtained at the scattering Brewster angle Θ _B , the correlation distance of the evaluation plane can be calculated based on the ratio between the intensity of the P polarization component and the intensity of the S polarization component. Direct measurement is possible. Similarly, the surface roughness can be obtained from the correlation distance and the intensity of electromagnetic wave scattering inside the sample.

FIG. 8 shows the scattering Brewster angle Θ '.
It is a second embodiment of the evaluation surface roughness measuring device that embodies the evaluation surface roughness measurement method using the scattered wave to _B2 , and is used as an electromagnetic wave irradiation unit that irradiates an electromagnetic wave containing only a P polarization component. A laser light source 31 and a sample 32 from the laser light source 31
A polarizing beam splitter 33 arranged to receive the scattered light of the laser irradiated on the surface at a scattering Brewster angle Θ ′ _B2 , and a first method for obtaining the S-polarized light component separated by the polarizing beam splitter 33 A first photodetector 34 as a scattered wave acquisition unit and the polarization beam splitter 33
A second photodetector 35 as a second scattered wave obtaining means for obtaining the P-polarized component separated by the first and second photodetectors 34, 35, and the intensity of the P-polarized component obtained from the first and second photodetectors 34, 35 and S Roughness calculating means for calculating the correlation distance of the evaluation surface of the sample 32 based on the ratio with the intensity of the polarization component, and further calculating the surface roughness based on the correlation distance and the intensity of electromagnetic wave scattering inside the sample 22. And a computer 36.

In the roughness measuring apparatus for the evaluation surface according to the second embodiment, similarly to the first embodiment described above, two parameters indicating the roughness of the evaluation surface, “surface roughness” and “correlation” are used. The distance can be determined individually, and the roughness of the evaluation surface can be substantially measured. In the second embodiment, the scattered wave incident from the upper surface 32a of the sample 32 and scattered inside is lower than the lower surface 32b of the sample 32.
Therefore, it is a necessary condition that scattering on the lower surface 32b is smooth enough to be ignored.

[0041]

As described above, according to the method for measuring the roughness of the evaluation surface according to the first aspect, the intensity of the co-polarization component obtained at the scattering Brewster angle Θ _B1 where the relational expression of Expression 9 holds. And the intensity of the cross-polarization component changes according to the surface roughness and the correlation distance, but the ratio between the intensity of the co-polarization component and the intensity of the cross-polarization component becomes almost constant without depending on the surface roughness. Using the basic property described above, the correlation distance of the evaluation plane can be calculated based on the ratio of the intensity of the S-polarized component to the intensity of the P-polarized component of the scattered wave obtained at the scattered Brewster angle Θ _B1 .

Further, the method for measuring the roughness of the evaluation surface according to claim 2 is provided.
According to the method, the scattering Brewster angle Θ _B1Acquired at
Of the S-polarized component with respect to the P-polarized component of the scattered wave
From the correlation distance calculated based on the ratio of
The surface roughness can be calculated on the basis of the electromagnetic wave scattering intensity.

According to the method for measuring the roughness of the evaluation surface according to the third aspect, the intensity of the co-polarization component and the cross-polarization component obtained at the scattering Brewster angle Θ ′ _B2 satisfying the relational expression (10) are satisfied. Varies depending on the surface roughness and the correlation distance,
Utilizing the basic property that the ratio of the intensity of the co-polarization component to the intensity of the cross-polarization component is almost constant without depending on the surface roughness, the scattering obtained at the scattering Brewster angle Θ ' _B2 The correlation distance of the evaluation plane can be calculated based on the ratio of the intensity of the S polarization component to the intensity of the P polarization component of the wave.

Further, according to the method for measuring the roughness of the evaluation surface according to the fourth aspect, the ratio of the intensity of the S-polarized component to the intensity of the P-polarized component of the scattered wave obtained at the scattered Brewster angle Θ ′ _B2 . The surface roughness can be calculated based on the correlation distance calculated on the basis of and the electromagnetic wave scattering intensity inside the sample.

According to the apparatus for measuring the roughness of an evaluation surface according to claim 5, the intensity of the co-polarization component and the intensity of the cross-polarization component obtained at the scattering Brewster angle Θ _B1 satisfying the relational expression 9 are satisfied. Although the intensity changes according to the surface roughness and the correlation distance, the basic property that the ratio between the intensity of the co-polarized component and the intensity of the cross-polarized component is almost constant without depending on the surface roughness. From the scattered waves scattered on the evaluation surface by irradiating the P-polarized electromagnetic wave from the electromagnetic wave irradiation means using the P-polarized electromagnetic wave, the S-polarized component is obtained by the first scattered wave obtaining means, and the P-polarized component is obtained by the second scattered wave obtaining means. The roughness calculating means can calculate the correlation distance of the evaluation plane based on the ratio between the intensity of the P-polarized component and the intensity of the S-polarized component.

Further, according to the roughness measuring apparatus for the evaluation surface according to the sixth aspect, the correlation distance calculated by the roughness calculating means based on the ratio between the intensity of the P-polarized component and the intensity of the S-polarized component is calculated. The calculating means can calculate the surface roughness based on the electromagnetic wave scattering intensity from the sample surface.

According to the roughness measuring apparatus for an evaluation surface according to the seventh aspect, the intensity of the co-polarization component and the cross-polarization component obtained at the scattering Brewster angle Θ ′ _B2 satisfying the relational expression 10 are satisfied. Varies depending on the surface roughness and the correlation distance,
Utilizing the fundamental property that the ratio of the intensity of the co-polarized component to the intensity of the cross-polarized component is almost constant without depending on the surface roughness, the P-polarized electromagnetic wave is irradiated from the electromagnetic wave irradiation means. From the scattered waves scattered inside the sample, an S-polarized component is obtained by the first scattered wave obtaining means, and a P-polarized component is obtained by the second scattered wave obtaining means. The roughness calculating means can calculate the correlation distance of the evaluation surface based on the ratio of the component to the intensity.

Further, according to the evaluation surface roughness measuring apparatus according to the eighth aspect, the correlation distance calculated by the roughness calculating means based on the ratio of the intensity of the P polarization component to the intensity of the S polarization component is obtained. The calculating means can calculate the surface roughness based on the intensity of the electromagnetic wave scattered into the sample.

[Brief description of the drawings]

1 is a diagram illustrating a principle of the scattering Brewster angle theta _B1 caused by the electromagnetic wave irradiated to the dielectric surface scattering Brewster angle theta _'B2.

FIG. 2A is a scattered intensity distribution diagram with respect to a scattering angle of an S-polarized component of a scattered wave scattered on an evaluation surface having a small roughness. (B) is a scattering intensity distribution diagram with respect to the scattering angle of the P polarization component of the scattered wave scattered on the evaluation surface having a small roughness.

FIG. 3 is a distribution diagram of scattering intensity with respect to the scattering angle of an S-polarized component and a P-polarized component of a scattered wave scattered on an evaluation surface having a large roughness.

FIG. 4 is a schematic block diagram of a non-contact surface roughness evaluation device according to a first evaluation method.

FIG. 5 is a schematic block diagram of a non-contact surface roughness evaluation device according to a second evaluation method.

FIG. 6A is a characteristic curve diagram of the S / P ratio with respect to the scattering angle, which is shown by changing the surface roughness while keeping the correlation distance constant. (B) is a characteristic curve diagram of the S / P ratio with respect to the scattering angle, which is shown by changing the correlation distance while keeping the surface roughness constant.

FIG. 7 is a schematic block diagram showing a first embodiment of an evaluation surface roughness measuring apparatus according to the present invention.

FIG. 8 is a schematic block diagram showing a second embodiment of an evaluation surface roughness measuring apparatus according to the present invention.

[Explanation of symbols]

 Reference Signs List 21 laser beam limit 22 sample 23 beam splitter 24 first photodetector 25 second photodetector 26 computer

Claims (8)

(57) [Claims] When an electromagnetic wave of P polarization is irradiated on an evaluation surface of a dielectric which is a sample for measuring roughness of an evaluation surface, an incident angle θ
_{In accordance with 0} and the relative refractive index n of the dielectric with respect to the electromagnetic wave irradiation side medium, the scattering Brewster angle Θ _B1 in the electromagnetic wave irradiation side medium is expressed as follows. Under the conditions that satisfy the condition, the correlation distance of the evaluation plane is calculated based on the ratio of the intensity of the S-polarized component to the intensity of the P-polarized component of the scattered wave obtained at the scattering Brewster angle Θ _B1 . Characteristic measurement method for the roughness of the evaluation surface. 2. A correlation distance obtained based on a ratio of an intensity of an S-polarized component to an intensity of a P-polarized component of a scattered wave obtained at a scattered Brewster angle 1 _B1 and an electromagnetic wave scattering intensity from a sample surface. The method for measuring the roughness of an evaluation surface according to claim 1, wherein the surface roughness of the evaluation surface is determined based on the evaluation value. 3. A method for measuring the roughness of a dielectric, which is a sample for measuring the roughness of an evaluation surface.
When an electromagnetic wave of P polarization is irradiated on the evaluation surface, the incident angle θ
₀And the relative refractive index n of the dielectric with respect to the electromagnetic wave irradiation side medium
Accordingly, the scattering bruise on the dielectric side where the electromagnetic wave is incident
Star angle Θ ' _B2But,Under the condition that satisfies_B2At
S-polarization component with respect to the intensity of the P-polarization component of the acquired scattered wave
Calculate the correlation distance of the evaluation surface based on the ratio of the intensity of the minute
A method for measuring the roughness of an evaluation surface, characterized in that: 4. A correlation distance obtained based on a ratio of the intensity of the S-polarized component to the intensity of the P-polarized component of the scattered wave obtained at the scattering Brewster angle Θ ′ _B2 , and the intensity of the electromagnetic wave scattered inside the sample. 4. The method for measuring the roughness of an evaluation surface according to claim 3, wherein the surface roughness of the evaluation surface is determined based on the following formula. 5. An electromagnetic wave irradiating means for irradiating a P-polarized electromagnetic wave to an evaluation surface of a dielectric which is a sample for measuring the roughness of the evaluation surface, and an incident angle θ _{0 of the} electromagnetic wave irradiated from the electromagnetic wave irradiating means.
According to the relative refractive index n of the dielectric with respect to the electromagnetic wave irradiation side medium and the electromagnetic wave irradiation side medium, the scattering Brewster angle Θ _B1 in the electromagnetic wave irradiation side medium is given by A first scattered wave obtaining means for obtaining an S-polarized wave component of the scattered wave at the scattered Brewster angle Θ _B1 under the condition satisfying the second condition, and a second scattered wave obtaining means for obtaining the P-polarized wave component of the scattered wave at the scattered Brewster angle Θ _B1 A scattered wave acquisition unit, and a correlation distance of an evaluation plane based on a ratio of the intensity of the P polarization component acquired by the second scattered wave acquisition unit to the intensity of the S polarization component acquired by the first scattered wave acquisition unit. And a roughness calculating means for calculating a roughness of the evaluation surface. 6. An evaluation surface based on a correlation distance obtained based on a ratio of an intensity of an S-polarized component to an intensity of a P-polarized component and an electromagnetic wave scattering intensity from a sample surface. The apparatus for measuring the roughness of an evaluation surface according to claim 5, wherein the surface roughness is calculated. 7. An electromagnetic wave irradiating means for irradiating a P-polarized electromagnetic wave to an evaluation surface of a dielectric which is a sample for measuring the roughness of the evaluation surface, and an incident angle θ _{0 of the} electromagnetic wave irradiated from the electromagnetic wave irradiating means.
According to the relative refractive index n of the dielectric with respect to the electromagnetic wave irradiation side medium and the electromagnetic wave incident side medium, the scattered Brewster angle Θ ′ _B2 on the dielectric side where the electromagnetic wave is incident is given by: A first scattered wave obtaining means for obtaining an S-polarized component of the scattered wave at the scattered Brewster angle Θ ′ _B2 under the condition that:
A second scattered wave obtaining means for obtaining a P-polarized component of the scattered wave at the scattered Brewster angle Θ '_B2; and a P-polarized component intensity obtained by the second scattered wave obtaining means and the first scattered wave obtaining means. A roughness calculating means for calculating a correlation distance of the evaluation surface based on a ratio of the acquired intensity of the S-polarized component to the S surface polarization component; 8. An evaluation surface based on a correlation distance obtained based on a ratio of an intensity of an S-polarized component to an intensity of a P-polarized component and the intensity of electromagnetic wave scattering inside the sample. The roughness measuring device for an evaluation surface according to claim 7, wherein the surface roughness is calculated.