JP2946399B2 - Mirror contamination detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirror contamination detecting apparatus suitable for a processing apparatus for conducting synchrotron radiation to a workpiece through a mirror and performing ablation processing of Teflon material or the like.

[0002]

2. Description of the Related Art Conventionally, a synchrotron radiation light (hereinafter, referred to as SR light) from a synchrotron radiation light generator (hereinafter, referred to as SR light generation device) is guided to a workpiece through a deflecting device, and then to a Teflon material. It has been proposed to process etc. This will be described briefly with reference to FIG. FIG.
, The SR light 1 radiated from the SR light generator 11
2 is guided to the processing vessel 14 by a vacuum duct 13 (not shown in the middle), a part of which is indicated by a broken line in the figure. The SR light 12 has a constant thickness in a vertical plane and forms a beam having a rectangular cross section. A mirror 15 having a flat reflecting surface is arranged on the optical path in the vacuum duct 13 so as to reflect the SR light 12 and deflect the optical path in the vertical direction. Mirror 15
Are arranged so as to rotate around the rotation axis 16 within a predetermined angle range. The rotation of the mirror 15 is
This is performed by an actuator 17 coupled to. A speed controller 18 is connected to the actuator 17 and controls the rotation speed of the mirror 15 so as to change according to the rotation angle position. The vacuum duct 13 is connected to the processing container 14.

[0003]

By the way, since this type of processing apparatus has a structure having a mirror, the reflection surface of the mirror, the electron collision desorption operation, etc., due to the SR light and the like due to the use of the apparatus, In particular, a substance adheres to and contaminates a portion to which SR light is actually applied. The contaminants are caused by gas remaining in the vacuum duct, Teflon of the object to be processed, and the like, and therefore, there are many hydrocarbon-based compounds, that is, compounds mainly containing carbon. When the mirror is contaminated, the original reflectance of the mirror decreases, and the deflected SR
There is a problem that the intensity of light output is reduced. If not, the SR light intensity required for processing cannot be obtained. In particular, the amount of fragments from the workpiece as a contamination source is much larger than the residual material in the vacuum duct, and the degree of contamination of the mirror is high, which is a problem.

Accordingly, there is a demand for maintenance such as detecting the contamination of the mirror and cleaning the mirror when a predetermined amount of the contamination occurs. In particular, the detection of mirror contamination does not hinder the normal operation of the deflecting device.
In addition, it is required that the device need not be disassembled before the necessity of the cleaning operation is recognized. Further, it is required that the detection result is accurate and that the structure for detection is simple.

[0005] An object of the present invention is to provide a mirror contamination detecting device capable of detecting the contamination of a mirror without disturbing the normal operation of the deflecting device and the processing device and without disassembling the device. .

Another object of the present invention is to provide a mirror contamination detecting device capable of accurately detecting mirror contamination with a simple configuration.

[0007]

According to the present invention, the present invention is applied to a processing apparatus for performing processing by guiding synchrotron radiation from a synchrotron radiation generator to a workpiece through a mirror. A diffraction grating disposed at an extraction angle capable of extracting a spectrum near a photon energy related to an absorption edge of an element of a main component of a contaminant attached to the mirror from the reflected light within an optical path range of the reflected light; A diffraction grating driving unit that moves the diffraction grating into and out of the optical path range of the reflected light; and a spectral light receiving region that is made of the same main component as the main component of the contaminant and that can receive the spectral light from the diffraction grating. And a wire for detecting the photocurrent of the spectroscopy, and detecting the amount of the contaminant attached based on the photocurrent detected by the wire. It is.

According to the present invention, there is also provided the mirror contamination detecting device having a wire driving unit for moving and adjusting the wire to a position in the spectral light receiving area where the spectral intensity is the maximum.

According to the present invention, there is further provided the mirror contamination detecting device corresponding to the case where the main component of the contaminant is one of a plurality of types of main component candidates, wherein the diffraction grating detects the main component. The extraction angle can be adjusted according to the main component of the contaminant to be formed, and the wire is prepared in a plurality of types having different main components so as to correspond to the main component candidates, and from among the prepared wires. There is obtained a mirror contamination detection device which is selectively moved to the spectral light receiving region according to a main component of the contaminant to be detected.

[0010]

Generally, the SR light generated by the SR light generator is
The photon flux has a distribution according to the photon energy.
Therefore, the reflected light of the mirror in the deflecting device also exhibits a distribution of the photon flux according to the photon energy, and the size of the photon flux is based on the reflectance (absorbance) of the mirror reflection surface for SR light. Then, the absorptance of the mirror for SR light is based on the degree of contamination of the mirror reflection surface. Therefore,
In the present invention, the degree of contamination of the mirror is detected by detecting the photon flux of the mirror reflected light.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing an embodiment according to the present invention, the relationship between the degree of mirror contamination and the photon flux will be described.

The inventors conducted an experiment to measure the relationship between the degree of contamination of the mirror and the distribution of the photon flux using the SR light generating device and the deflecting device. As the mirror, a cleaned mirror and a mirror that was artificially contaminated were used. The contaminant here was carbon as a typical main component of the actual contaminant, as described later.

FIG. 2 is a diagram showing the relationship between the photon energy and the photon flux of each SR light reflected by various mirrors of the deflecting device. In FIG. 2, the thin solid line a is the reflected light from the cleaned mirror, which is substantially equal to the light (not shown) generated by the SR light generator. The thick solid line b indicates the case where carbon was attached to the cleaned mirror to a thickness of 10 nm. In this case, the photon flux is lower over the entire range of about 100 eV or less than the solid line a, and
It is sharply low at 84.2 eV and is low even in the range of more than several hundred eV. The broken line c shows the case where carbon was attached to the cleaned mirror to a thickness of 100 nm. In this case, the photon flux is 284.
It is low over the entire range of 2 eV or less and 284.2 eV.
, Sharply and remarkably low, and even in the range of several hundred eV or less. Here, in the solid line b and the dashed line c, the photon flux at a photon energy of 284.2 eV is sharply low.
This is because the absorption edge of the carbon element as a contaminant of the mirror (so-called K edge of carbon) is at a photon energy of 284.2 eV.

From the above experimental results, if the contaminant is detected by detecting the photon flux, the photon energy is about 10
A photon flux of 0 eV or less, or a photon energy related to the absorption edge of the main component element of the contaminant (2
It is understood that the photon flux near 84.2 eV) may be detected. However, the practical range of the photon energy required for the SR light focusing / deflecting device for processing the Teflon material is approximately several tens eV.
There is a fact that the range is above. Therefore, in the present invention, by detecting near-photon energy (284.2 eV for the carbon element) of the SR light reflected by the mirror related to the absorption edge of the main component element of the contaminant attached to the mirror, The amount of contaminants attached is detected, and the degree of mirror contamination is detected.

As the contaminants, it is considered that hydrocarbon compounds remaining in the vacuum duct are ionized and adhered. In particular, when used as ablation processing apparatus, if the object is, for example Teflon C, CF, CF ₂ or the like is attached ionized. The chemical formula of the above Teflon is represented by the following chemical formula 1.

[0016]

Embedded image As described above, since the contaminants generally contain carbon as the main component, the above experiment and the following examples are configured for the case where the main component of the contaminants is carbon.

Hereinafter, a mirror contamination detecting apparatus according to an embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a diagram showing an SR light deflecting device. In FIG. 1, a mirror 2 whose posture is changed within a predetermined range is arranged in a vacuum duct 1, and an SR (not shown) is provided.
The SR light 100 from the light generation device (left side in the figure) is mirrored by 2
To deflect.

The mirror contamination detecting means according to the present embodiment includes a main component of the contaminant adhering to the mirror 2 in the reflected light 100 'in the optical path of the reflected light 100' of the SR light 100 from the mirror 2. The photon energy (284.2) related to the absorption edge (K edge) of the (carbon in this example) element
eV) A diffraction grating 3 (for example, a plane diffraction grating having a line pitch of 600 lines / mm) arranged at an extraction angle capable of extracting the nearby spectral component 100 '', and an optical path of the reflected light 100 ' Diffraction grating driving unit 4 composed of a linear motor or the like that moves in and out of the range (in the vertical direction in the figure)
And a carbon wire made of carbon, which is the same main component as the main component of the contaminant, and arranged in a spectral light receiving region capable of receiving the spectrum 100 ″ from the diffraction grating 3 and detecting the photocurrent of the spectrum 100 ″ 5 and a wire driving unit (not shown) for moving and adjusting the carbon wire 5 to a position (described later) having the maximum intensity of the spectrum 100 ″ in the spectral light receiving area. With the above configuration, the mirror contamination detection means detects the amount of carbon as a contaminant based on the value of the photocurrent detected by the carbon wire 5.

The spectral light receiving area of the carbon wire 5 is based on the width of the spectrum 100 ″, that is, the width of light incident on and reflected from the diffraction grating 3. Here, it is a matter of course that the spectrum 100 ″ exhibits an intensity distribution. Therefore, it is preferable to detect the photocurrent by moving and adjusting the carbon wire 5 by the wire driving unit to the position where the spectral intensity is 100 '' in the spectral light receiving area, to realize accurate detection.

It is possible to estimate a decrease in reflectance due to mirror contamination by directly irradiating the carbon wire 5 with the reflected light 100 ′ from the mirror 2 without passing through the diffraction grating 3. 284.2 by K edge of
When the component of eV is small compared to the other components, high-sensitivity detection is possible by separating light with the diffraction grating 3. That is, when the main component of the contaminant of the mirror is specified, it is more efficient to detect the contamination using the absorption action of the main component.

On the other hand, the same detection is performed in advance by the mirror 2 which has been cleaned or the mirror 2 having a degree of contamination before the operation of the apparatus is substantially hindered, and the photocurrent value at that time is used as a reference value. By storing the reference value and the detected value, the degree of contamination of the mirror 2 can be determined.
It is determined whether or not cleaning work is required.

Incidentally, the optical path range of the reflected light 100 'means the range of the optical path change of the reflected light 100' based on the change of the attitude of the mirror 2. Therefore, in the present embodiment, when the degree of contamination is detected by the diffraction grating driving unit 4, the diffraction grating 3 is moved into the optical path range so as to extract the spectrum 100 '', while the SR light converging / deflecting device of the present SR light is used. During normal operation, the diffraction grating 3 is retracted out of the optical path range so as not to adversely affect the operation.

Further, the diffraction grating 3 allows the spectroscopy 10 near the photon energy related to the absorption edge of the main component element of the contaminant.
In order to extract 0 ″, the exit angle from the diffracted photon 3 needs to be a predetermined angle. For example, in order to split the wavelength around 284.2 eV of the photon energy related to the K edge of the carbon element, it is preferable to set the exit angle from the diffracted photon 3 to 85 ° and the incident angle to 86 °. Therefore, the extraction angle of the diffraction grating 3 in this embodiment is an angle at which the incident angle of the reflected light 100 ′ from the mirror 2 is 86 ° and the emission angle is 85 °. In this embodiment, since the diffraction grating 3 is configured to move vertically in the drawing, the diffraction grating 3 is fixed in advance at the above-mentioned extraction angle with respect to the axis of the diffraction grating driving unit 4. Thereafter, there is no need to adjust the angle.

In the mirror contamination detection apparatus described above, the operation of each drive unit, the storage of the reference value of the photocurrent value, the comparison of the detected value with the reference value, and the like are controlled by a control unit including a microcomputer or the like. It is possible to

The embodiment described above has a configuration corresponding only to the case where the main component element of the pollutant is carbon.
However, when there are a plurality of types of main component candidates having different main components of the contaminants, the extraction angle of the diffraction grating can be adjusted according to the main components of the contaminants to be detected, so that the extraction angle is related to the absorption edge of each main component. The extraction angle from the diffracted photon is set to an angle corresponding to each absorption edge so as to extract the spectrum near the photon energy, and a plurality of types of different main components are prepared as wires corresponding to the main component candidates, In addition, it is configured to selectively move to the spectral light receiving region according to the main component of the contaminant to be detected from the prepared, that is, to selectively move the wire composed of the same main component as the contaminant to the spectral light receiving region. . Also in this case, the control unit may control the adjustment of the extraction angle of the diffraction grating and the selective movement of the wire.

In the present invention, it is possible to provide a means for automatically cleaning the mirror without disassembling the apparatus when the mirror contamination detection apparatus determines that the mirror needs to be cleaned. .

The present invention can also be applied to the case of detecting mirror contamination that simply changes the optical path.

[0029]

The mirror contamination detection apparatus according to the present invention is applied to a processing apparatus for performing processing by guiding synchrotron radiation light from a synchrotron radiation light generation apparatus to a workpiece through a mirror, and reflects light reflected by the mirror. A diffraction grating arranged at an extraction angle capable of extracting the spectrum near the photon energy related to the absorption edge of the element of the main component of the contaminant adhering to the mirror from the reflected light within the optical path range; A diffraction grating driving unit that moves inside and outside the optical path range of the reflected light;
A wire that is composed of the same main component as the main component of the contaminant, is disposed in a spectral light receiving region capable of receiving the spectrum from the diffraction grating, and has a wire for detecting the photocurrent of the spectrum, and based on the photocurrent detected by the wire. Since the amount of the contaminants attached is detected by the method, the normal operation of the apparatus is not hindered, and the contamination of the mirror can be detected without disassembling the apparatus.

Further, although the configuration is simple, the contamination of the mirror can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of a mirror contamination detection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between photon energy and photon flux of light reflected by various mirrors having different amounts of carbon deposition.

FIG. 3 is a conceptual perspective view showing a conventional processing apparatus using synchrotron radiation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 13 Vacuum duct 2 Mirror 3 Diffraction grating 4 Diffraction grating driving part 5 Carbon wire 11 Synchrotron radiation light generator 12 Synchrotron radiation (SR light) 14 Processing container 16 Mirror 100 Synchrotron radiation (SR light) 100 ' Reflected light 100 '' spectral

Claims (3)

(57) [Claims] The present invention is applied to a processing apparatus for performing processing by guiding synchrotron radiation light from a synchrotron radiation light generation device to a workpiece via a mirror, and performing the reflection within the optical path range of the light reflected by the mirror. A diffraction grating arranged at an extraction angle capable of extracting a spectrum in the vicinity of photon energy relating to an absorption edge of an element of a main component of a contaminant attached to the mirror from light; and an optical path of the reflected light. A diffraction grating driving unit that moves in and out of the range, which is composed of the same main component as the main component of the contaminant, is disposed in a spectral light receiving region capable of receiving the spectrum from the diffraction grating, and detects a photocurrent of the spectrum. A mirror contamination detection device, comprising: a wire; and detecting an attached amount of the contaminant based on the photocurrent detected by the wire. 2. The mirror contamination detection device according to claim 1, further comprising a wire driving unit configured to move and adjust the wire to a position in the spectral light receiving area where the spectral power has the maximum intensity. 3. The method according to claim 1, wherein the main component of the contaminant is one of a plurality of types of main component candidates.
Or the mirror contamination detection device according to 2, wherein the diffraction grating is capable of adjusting the extraction angle according to a main component of the contaminant to be detected, and the wire corresponds to the main component candidate. A mirror contamination detection device, wherein a plurality of types having different main components are prepared, and the prepared components are selectively moved to the spectral light receiving area according to the main components of the contaminants to be detected from the prepared main components.