JPH1054793A - Spectral reflection light amount measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure spectral reflection light amount accurately regardless of character of an object to be measured without changing measuring performance to the spectral reflection light amount. SOLUTION: Measuring light from a first lamp 13 is passed through a pin hole 20a and the outer surface F of a substrate 12 is irradiated with the light through an optical system 6 with an irradiating are of the measuring light being restricted. Reflected light from the outer surface F of the substrate 1 is taken in a spectral unit 9 through the optical system 6 and the light amount of the reflected light is measured. A protecting glass 25 is disposed between the optical system 6 and the outer surface F of the substrate to prevent dust from dropping on the outer surface F of the substrate 12 and also prevent heat, gas and vapor from the substrate 12 side from being effected to the optical system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the amount of reflected light on the surface of a sample to be measured, such as the outer surface of a substrate, in order to specify a substance or measure the thickness of a film.

[0002]

2. Description of the Related Art Conventionally, a microspectroscope as disclosed in Japanese Patent Publication No. 7-3365 has been proposed for measuring the amount of spectrally reflected light on the surface of a sample to be measured which has been subjected to a surface treatment as described above. was there.

According to such a conventional microspectroscope,
Above the measurement sample surface, the microscope optical system is moved so as to measure a desired portion of the measurement sample surface, and a microscope objective lens constituting the microscope optical system is opposed to the measurement sample surface to measure the amount of spectral reflection light. Is configured.

[0004]

However, in the above-described apparatus, there are many movable parts such as a revolver for switching an objective lens, a focusing mechanism, and an XY stage for moving an optical system. There is.

When these movable parts are operated above the surface of the measurement sample, dust may be generated. When the dust falls on the surface of the measurement sample, the reflection of the measurement light is disturbed, and the spectral reflection light amount is increased. There is a drawback that the measurement accuracy of the sample decreases.
In addition, there is a disadvantage that contamination of the object to be measured is caused.

Further, when the temperature of the object to be measured is high, or when a gas component or a vapor component is volatilized from the processing liquid on the object to be measured, distortion or dirt is generated in the optical system due to the properties of the object to be measured. This has the disadvantage that the measurement accuracy of the spectral reflected light quantity is reduced.

The present invention has been made in view of such circumstances, and the spectral reflection light amount measuring apparatus according to the first aspect of the present invention does not change the measurement performance for the spectral reflection light amount, and does not change the measurement performance. The aim is to be able to accurately measure the amount of spectral reflected light, regardless of its properties,
Further, the spectral reflection light amount measuring device of the invention according to claim 2 is:
It is an object of the present invention to avoid a decrease in measurement accuracy due to dust generated by the operation of the device.

[0008]

The invention according to claim 1 is
In order to achieve the above-described object, a light source that emits measurement light, and an optical system that causes the measurement light from the light source to reach the measurement sample surface and capture reflected light from the measurement sample surface,
In a spectroreflected light quantity measuring device equipped with a specular reflected light quantity measuring means for measuring the quantity of reflected light for each specific wavelength from the surface of the measured sample taken into the optical system, protection for separating the optical system side from the measured sample surface The apparatus includes a transparent body and an irradiation range limiting unit that limits an irradiation range of the measurement light from the light source on the measurement sample surface.

According to a second aspect of the present invention, there is provided an apparatus for measuring the amount of reflected reflected light, wherein the optical system of the apparatus for measuring the amount of reflected reflected light is moved in a horizontal direction. Moving means, and a protective transparent body is provided between the optical system and the surface of the measurement sample below the optical system.

[0010]

According to the configuration of the spectral reflection light amount measuring device of the invention according to the first aspect, the measurement sample is transmitted to the measurement sample surface and the reflection light from the measurement sample surface while passing through the protective transparent body. Even if an object to be measured having a surface is at a high temperature, or a gas component or a vapor component is volatilized and generated from a treatment liquid on the object to be measured, the effect can be blocked by the protective transparent body. Moreover, the irradiation range restricting means restricts the irradiation range of the measurement light from the light source on the surface of the measurement sample, and is configured as a so-called Koana-Naora type optical system.
The effect due to the V effect can be reduced, and the effect due to irregular reflection at the boundary caused by the protective transparent body can be suppressed.

Further, according to the configuration of the spectral reflection light amount measuring device of the invention according to the second aspect, even if dust is generated by the operation of the movable part on the device side such as the optical system, the dust drops on the surface of the measurement sample. Can be prevented by the protective transparent body.

[0012]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall side view of a spectral reflection light amount measuring device according to an embodiment of the present invention, and FIG. 2 is an overall configuration diagram showing a spectral reflection light amount measurement optical system. As shown in FIG. 1, a first stage 3 is mounted on a support 2 erected on a base 1.
X as a moving means composed of a and the second stage 3b
The optical system 4 for measuring the amount of reflected spectral light via the Y stage 3
A casing 5 containing therein (see FIG. 2) is supported movably in the horizontal direction.

As shown in FIG. 2, the spectral reflection light amount measuring optical system 4 includes an optical system 6, an illumination system 7, a monitor system 8, and a spectral unit 9.

The optical system 6 includes an objective lens 10 and a first convex lens 11, and allows measurement light from the illumination system 7 to reach an outer surface F of the substrate 12 as a measurement sample surface, and from the outer surface F of the substrate 12. Is reflected, and an image of the outer surface F of the substrate 12 is formed on the spectral unit 9. Note that the objective lens 10 and the first convex lens 11 are each shown as one lens, but may be made up of a plurality of lenses, and so on.

The illumination system 7 includes a first lamp 13 as a light source for emitting measurement light, second and third convex lenses 14,
15 and a first beam splitter (may be a half mirror) 16 provided between the objective lens 10 and the first convex lens 11. The illumination system 7 includes a second lamp 17 as a monitor light source, a shutter 18, a fourth convex lens 19, and a second convex lens 1.
A pinhole mirror 20 provided between the fourth and third convex lenses 15 is provided.

The monitor system 8 includes a CCD camera 21 and a fifth
, And a second beam splitter (may be a half mirror) 23 provided between the first convex lens 11 and the spectral unit 9. As the monitor system 8, an eyepiece may be provided instead of the CCD camera 21 so as to be visually observed.

A pinhole 2 is provided on the image forming surface of the spectral unit 9.
4 are provided and are configured to limit the area measured on the outer surface F of the substrate 12. And, although not shown,
The reflected light passing through the pinhole 24 is taken into various kinds of spectral reflected light amount measuring means such as a spectroscope combining a flat imaging type diffraction grating and a photodetector array. The amount of reflected light for each specific wavelength from the outer surface F is measured to obtain spectral information of the reflected light.

Below the objective lens 10, the XY stage 3 and the optical system 6 extend vertically downward over the entire movable area of the optical system 6, and are supported by the column 2. On the other hand, a protective glass 25 is provided as a protective transparent body that partitions the optical system 6 side.

The pinhole mirror 20 is provided with a pinhole 20a as irradiation range limiting means, and is configured to limit the irradiation range in which the measurement light from the first lamp 13 irradiates the outer surface F of the substrate 12. ing. That is, only the measurement light that has passed through the pinhole 20a is applied to the outer surface F of the substrate 12.
So-called Koana-
It is configured as a Naora type optical system and configured to reduce the influence of the SV effect. Thereby, the illumination system 7
In addition, in each of the optical systems 6, a flare light generated by a lens, a protective surface of the protective glass 25, a minute flaw, dirt, and hardware supporting those optical components, or a reflected light from the protective glass 25. The resulting measurement error can be suppressed. The pinhole 20a of the pinhole mirror 20 and the outer surface F of the substrate 12 are connected to the CCD camera 2
They are arranged so as to be optically conjugate when focused with 1.

Next, measurement of the amount of reflected light will be described.
First, the substrate 12 is moved and fixed to a position below the protective glass 25 facing the objective lens 10.

Next, the shutter 18 is opened, and the light from the second lamp 17 is applied to the outer surface F of the substrate 12 over a wide range. In this state, focusing is performed using an image from the CCD camera 21, and the XY stage 3 is driven to move to a desired measurement location. The movement to the desired measurement location may be performed by moving the substrate 12.

After moving to a desired measuring point and stopping, the shutter 18 is closed. As a result, the measurement light from the first lamp 13 is applied only to a desired measurement location on the outer surface F of the substrate 12, the reflected light is taken in, and the reflected light quantity is measured in the spectroscopic unit 9.

With the above-described configuration, even if dust is generated and dropped by movement of the optical system 6 upon focusing and driving of the XY stage 3, the dust is received by the protective glass 25 and the outer surface F of the substrate 12 It is possible to prevent dust from dropping and adhering to the device. Even if the substrate 12 is in a high temperature state after the heat treatment, the high temperature heat can be prevented from being transmitted to the optical system 6 by the protective glass 25. Further, even when gas or vapor may be volatilized due to the processing liquid applied to the outer surface F of the substrate 12, the protective glass 25 prevents such gas or vapor from adhering to the optical system. Can be prevented. The protection glass 25 is replaced periodically or appropriately.

To configure the monitor system 8, as shown in the main part of the modification of FIG. 3, the pinhole 24 where the reflected light is incident on the spectroscopic unit 9 is formed as a pinhole mirror 26. The pinhole mirror 26 reflects light other than that used for spectroscopic measurement, and
(Eyepiece for visual observation).

The present invention is not limited to the above-described embodiment in which the optical system 6 is positioned above the outer surface F of the substrate 12 to measure the amount of spectral reflected light, as described above. Since the protective glass 25 can prevent adverse effects due to gas and vapor, for example, the optical system 6
May be configured to measure the amount of spectral reflected light by positioning. Alternatively, the optical system 6 may be positioned on the lateral side of the outer surface F of the substrate 12 in the horizontal direction to measure the amount of spectrally reflected light.

The protective transparent body is not limited to the protective glass 25, but may be a heat-resistant plastic such as an acrylic resin.

[0027]

As is apparent from the above description, according to the apparatus for measuring the amount of reflected reflected light according to the first aspect of the present invention, the object to be measured is heated at a high temperature while transmitting the measuring light and the reflected light through the protective transparent body. Irrespective of the properties of the DUT, such as gas components or vapor components evaporating from the processing liquid on the DUT, the optical system is not affected. Measurement accuracy does not decrease.

Moreover, when the measurement light and the reflected light are transmitted through the protective transparent body, they are irregularly reflected at the boundary between them. In the present invention, the irradiation range restricting means limits the irradiation range of the measurement light from the light source on the measurement sample surface. Limit the so-called Koan
Since the a-Naora type optical system is used to reduce the influence of the SV effect, it is possible to satisfactorily avoid a decrease in measurement accuracy due to the protective transparent body, and to perform measurement without changing the measurement performance of the spectral reflection light amount. Irrespective of the properties of the object, the amount of spectral reflected light can be measured with high accuracy.

According to the second aspect of the present invention, when a movable part such as an optical system on the apparatus side is disposed above the surface of the measurement sample, dust is generated by the operation of the movable part. However, since the protective transparent body prevents the dust from dropping on the measurement sample surface, it is possible to eliminate the occurrence of irregular reflection due to the dust falling on the measurement sample surface, and the optical system is disposed above the measurement sample surface. Can be measured with high accuracy even in the case where is arranged.

[Brief description of the drawings]

FIG. 1 is an overall side view showing a spectral reflection light amount measuring device according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram showing an optical system for measuring a spectral reflection light amount.

FIG. 3 is a configuration diagram of a main part of a modified example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 ... XY stage (moving means) 6 ... Optical system 9 ... Spectroscopy unit (spectral reflection light quantity measuring means) 13 ... First lamp 20a ... Pinhole (irradiation range limiting means) 25 ... Protective glass (protection) Transparent body) F: Outer surface of substrate (measurement sample surface)

Claims (2)

[Claims] A light source that emits measurement light; an optical system that causes the measurement light from the light source to reach a measurement sample surface and captures reflected light from the measurement sample surface; and the measurement sample surface that is captured by the optical system. A spectral reflection light amount measuring device for measuring the amount of reflected light for each specific wavelength from the light, a protective transparent body that partitions the optical system side from the measurement sample surface, and the measurement An irradiation range limiting unit that limits an irradiation range of the measurement light from the light source on the sample surface. 2. A spectral reflection light amount measuring apparatus comprising: a moving unit for moving the optical system according to claim 1 in a horizontal direction, wherein a protective transparent body is provided between the optical system and a measurement sample surface below the optical system. .