JP2000020075A - Air conditioner system, interferometer system, and exposure device system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner system, an interferometer system, and an exposure device system in which vibration caused by an air conditioner is less. SOLUTION: In an air conditioner 50 side of a duct 60, a first microphone 91 collects a noise NS from the air conditioner 50. A signal processing device 95 generates a signal having a waveform in which a phase is deviated from a waveform of a noise by the prescribed quantity based on a detected signal from the first microphone 91, a second microphone 92 generates a sound wave SW canceling the noise NS based on a signal from the signal processing device 95. Consequently, in the second microphone 92, the noise NS is hardly detected, and it can be prevented that a low frequency noise generated by the air conditioner 50 is diffused in a temperature controlled chamber 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioning system used for temperature control of a machine tool, a measuring instrument, a semiconductor exposure apparatus, and the like, and an interferometer system and an exposure apparatus system having the air conditioning system.

[0002]

2. Description of the Related Art In recent years, some measuring devices such as ultra-precision machine tools and interferometers require extremely high machining accuracy and measurement accuracy. In order to achieve the extremely high accuracy required of these devices, attention must be paid not only to the mechanism, configuration and rigidity of the device itself, but also to the environment in which the device is installed. In particular, it is clear that the temperature change in the environment and the vibration transmitted to the equipment from the environment have a great effect on the accuracy of the equipment described above. This is an essential condition for obtaining accuracy.

[0003] Usually, the response to the temperature change in the environment is strictly controlled by an air conditioner in which a device is installed in a constant temperature room in which temperature control is performed, or a chamber is provided for each device and the temperature control in the device is provided outside. By doing so, the accuracy required for the device is cleared.

On the other hand, with respect to the vibration transmitted to the apparatus from the floor, particularly the apparatus, the vibration isolator is provided between the floor and the apparatus to take measures to minimize the transmission to the apparatus body. In addition, separate independent foundations have been set up for installation, and measures have been taken to minimize vibration transmitted to the equipment by blocking the floor on the foundation from the outside floor.

FIG. 6 shows an outline of an exposure apparatus system as an example of a system which has been used for an ultra-precision machine tool, a measuring apparatus, etc., which has taken measures for temperature control and vibration isolation. The illustrated exposure apparatus system includes an exposure apparatus main body 110 used in an IC manufacturing process, and an anti-vibration table 1 on which the exposure apparatus main body is mounted.
20, a temperature control chamber 130 for accommodating them, an independent foundation 140 supporting the vibration isolation table 120, and a temperature control chamber 1
An air conditioner 150 for controlling the temperature in the interior 30 and a duct 160 for communicating the temperature control chamber 130 and the air conditioner 150
It is composed of

[0006] The air conditioner 150 is usually constituted by a heat exchanger 151 and a blower 153, and the air temperature controlled by the heat exchanger 151 is supplied to the duct 160 by the blower 153.
Is supplied into the temperature control chamber 130 through the filter 165. The temperature in the temperature control chamber 130 is constantly monitored by a sensor.
It is fed back to 0. The air conditioner 150 operates so that the temperature in the temperature control chamber 130 does not deviate from the set temperature. On the other hand, the independent foundation 140 is separated from the surrounding floor 170 so that the vibration of the surrounding floor 170 is not directly transmitted. In addition, a vibration isolation table 120 provided between the independent foundation 140 and the exposure apparatus main body 110 prevents transmission of vibration from the independent foundation 140 to the exposure apparatus main body 110.

[0007]

In recent years, the demand for ultra-precision of an exposure apparatus and an interferometer can be achieved only by controlling the temperature of the installation environment of the apparatus and taking measures against floor vibration as described in the previous section. The area that can not be done has been reached.

For example, the line width of an IC pattern required in a semiconductor manufacturing process of an exposure apparatus is 0.35 μm or less.
In the future, with the improvement of IC integration, 0.25μ
It is said that a line width of about m or even a line width of about 0.15 μm falls within the defense range of the exposure apparatus. For this reason, extremely high accuracy is also required for components constituting the exposure apparatus.

Further, an interferometer used for measuring the shape of an optical component of an exposure apparatus is required to have a measurement reproducibility on the order of λ / 10,000. For this reason, there has been a situation in which disturbance factors such as temperature change and vibration in the environment, which are not so far a problem, have been greatly focused on, and there has been a situation where countermeasures need to be taken.

One of the problematic disturbance factors is noise generated in the air conditioner of the temperature control chamber and transmitted through the duct into the temperature control chamber.

When applied to the exposure apparatus system shown in FIG. 6, the blower 153 of the air conditioner 150 and the heat exchanger 1
The noise generated from 51 is transmitted to the temperature control chamber 130 in which the exposure apparatus main body 110 is installed by using temperature-controlled air as a medium, and the exposure apparatus main body 110, that is, components such as the projection lens 112 and the wafer stage 113 In addition, the wafer 115 and the reticle 116 are vibrated. This causes a relative displacement between components of the exposure apparatus main body 110 and the like, which causes a problem that it is difficult to maintain a constant fine line width on the exposure surface.

Also, in the interferometer system, noise generated and transmitted for the same reason may cause an interferometer body installed in the chamber, for example, an optical system component such as a Fizeau lens which is the heart of the interferometer. Excite. By doing so,
A relative displacement occurs between the components of the interferometer body, causing a problem that fluctuations occur in interference fringes and it becomes difficult to maintain reproducibility of measurement.

Accordingly, an object of the present invention is to provide an air conditioning system, an interferometer system, and an exposure apparatus system in which vibration caused by air conditioning is small.

[0014]

In order to solve the above problems, an air conditioning system according to the present invention comprises an air conditioner, a chamber,
In an air conditioning system including the air conditioner and a duct connecting the chamber, a noise detection device that is disposed in one of the duct and the air conditioner and detects noise, and one of the duct and the air conditioner And a controller configured to generate a sound wave for canceling the noise detected by the noise detection device from the sound source.

In this air conditioning system, the control device generates sound waves from the sound wave source for canceling the noise detected by the noise detection device, so that vibrations caused by air conditioning are prevented from being transmitted into the chamber. Can be.

The exposure apparatus system of the present invention includes an air conditioner, a chamber containing an exposure apparatus main body for exposing a pattern on an original onto a photosensitive substrate, and a duct connecting the air conditioner and the chamber. In the exposure apparatus system, a noise detection device that is disposed in one of the duct and the air conditioner to detect noise, and a sound source that generates a sound wave that is disposed in one of the duct and the air conditioner, And a control unit configured to generate, from the sound source, a sound wave that cancels the noise detected by the noise detection device.

In this exposure apparatus system, the control unit generates a sound wave for canceling the noise detected by the noise detection device from the sound source, thereby preventing the vibration caused by air conditioning from being transmitted into the chamber. And precise exposure can be performed.

Further, the interferometer system of the present invention comprises an air conditioner, a chamber containing an interferometer body for optically measuring the shape of an object, and a duct connecting the air conditioner and the chamber. In the system, a noise detection device arranged in one of the duct and the air conditioner to detect noise, a sound source arranged in one of the duct and the air conditioner to generate a sound wave, A control device for generating, from the sound source, a sound wave that cancels the noise detected by the detection device.

In this interferometer system, since the control device generates a sound wave from the sound source for canceling the noise detected by the noise detection device, the vibration caused by air conditioning is prevented from being transmitted into the chamber. And accurate measurement can be performed.

[0020]

DESCRIPTION OF THE INVENTION According to the present invention, in a system such as a machine tool or a measuring instrument which requires high accuracy, an air conditioner is used to clean an internal air at a constant temperature in a chamber. The noise generated by the air conditioner in the chamber when performing precision processing or measurement is reduced by using an active noise reduction method.

It is believed that a significant portion of the noise in the chamber is caused by blowers and refrigerators in the air conditioner of the chamber. In an exposure apparatus system and an interferometer system used for measuring components thereof, since the apparatus body is large, the chamber and its air conditioner also become large, and the
Generates a low frequency vibration reaching up to 80 dB, which is applied to the device in the chamber. On the other hand, the eigenvalue of the vibration of the mechanical part of the device installed in the chamber is generally 100
Hz or less, which resonates with the low-frequency noise emitted from the air conditioner in the chamber into the chamber, causing unexpected vibrations in the equipment, which can be a factor in reducing machining accuracy and measurement accuracy. is there. In addition, a measuring instrument such as an interferometer is often extremely vulnerable to vibration of several tens of Hz, and therefore, silencing of low-frequency noise is extremely important for a device that pursues accuracy.

In order to reduce the noise in the chamber, it is common to use a silent type blower or refrigerator. However, in the case of an apparatus for performing ultra-precision processing or measurement, it is necessary to consider the required accuracy. Often, the effect is limited.

On the other hand, the active noise reduction technique used in the air conditioning system or the like of the present application is not a so-called passive noise reduction technique utilizing a well-known sound absorption phenomenon, resonance phenomenon, and the like. A second sound source is created, and as a result, noise is reduced by sound wave interference.
Furthermore, this technique can be expected to have a high noise reduction effect especially in a low frequency region, which is not good with a passive noise reduction technique using a sound absorbing material or the like. When effective at low frequencies, this technique is ideal for silencing chambers used in exposure equipment and interferometers that do not like minute vibrations.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An exposure apparatus system according to one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram for explaining the structure of an exposure apparatus system for reduction projection exposure. The illustrated exposure apparatus system includes an exposure apparatus main body 10 used in an IC manufacturing process,
An anti-vibration table 20 for mounting the exposure apparatus main body, a temperature control chamber 30 for accommodating them, an independent foundation 40 for supporting the anti-vibration table 20, and an air conditioner 50 for controlling the temperature inside the temperature control chamber 30; , A duct 60 for communicating the temperature control chamber 30 and the air conditioner 50, and an active silencer 90.

The exposure apparatus main body 10 includes a silicon wafer 15 and a reticle 16 in addition to components such as a projection lens 12 and a wafer stage 13. The temperature control chamber 30
An illumination light source 17 for exposure is disposed outside, and illumination light from the illumination light source 17 is guided into the temperature control chamber 30 via the mirror 18.

The temperature control chamber 30 isolates the exposure apparatus main body 10 from the outside to prevent a line width defect caused by a change in temperature during exposure.

The independent foundation 40 is separated from the surrounding floor 70 by interposing the cushioning material 80, so that vibrations from the floor 70 supported on the ground 100 by the columns 71 are not transmitted directly. . Further, the vibration isolation table 20 provided between the independent foundation 40 and the exposure apparatus main body 10 prevents transmission of vibration from the independent foundation 40 and the like to the exposure apparatus main body 10.

The air conditioner 50 includes a heat exchanger 51 and a blower 53 having a common fan and exhaust fan. The air whose temperature has been adjusted by the heat exchanger 51 is passed through a duct 60 and a filter 65 by a blower 53 to a temperature adjusting chamber 30.
Supplied within. The air conditioner 50 adjusts the operation of the heat exchanger 51 and the blower 53 so that the temperature in the temperature control chamber 30 does not deviate from the set temperature.

The active silencer 90 collects noise generated by the air conditioner 50 to detect a signal and a first microphone 91, and a second microphone 91 for monitoring noise near the outlet of the duct 60. A microphone 92; a signal processing device 95 that is a control device that generates a signal corresponding to a sound wave that cancels the noise based on the noise detected by the first microphone 91;
And a speaker 97 that is a sound wave source that generates a sound wave based on the signal generated by the speaker 97. Since the frequency of the noise that is the target of the active silencer 90 is in the range of tens of Hz to hundreds of Hz, the first and second microphones 91 and 92 are those having sensitivity up to a very low frequency for sound pressure measurement. The speaker 97 that generates the next sound wave also uses a large speaker system (super woofer) that is compatible with an extremely low frequency. The signal processing device 95 removes unnecessary sound wave components, filters for extracting frequencies to be silenced, a level adjuster for adjusting the amplitude of the signal, and a phase shift for generating a sound wave signal in which the phase of the noise signal is inverted. And a power amplifier for appropriately adjusting the power of the sound wave signal. Thereby, feedback is applied so that the sound pressure at the microphone 92 is minimized. The filters, level adjusters, and phase shifters used here are A / D converters, personal computers,
/ A converter.

The second microphone 92 is for adjusting the operation of the signal processing device 95 so that the vibration acceleration applied to the exposure apparatus main body 10 approaches zero. Therefore, instead of the second microphone 92, the servo-type vibration detection sensor 98 can be disposed on the anti-vibration table 20 supporting the exposure apparatus main body 10, and the vibration acceleration can be directly monitored.

First, a general operation of the exposure apparatus system will be described. Illumination light IL such as laser light emitted from an illumination light source 17 is applied to a reticle 16 corresponding to a negative film of an IC circuit pattern. The illumination light IL that has passed through the reticle 16 enters the projection lens 12, where it is reduced to a １ ／ image, and illuminates the silicon wafer 15 placed on the wafer stage 13. The silicon wafer 15 is set on the wafer stage 13 and can be moved to an arbitrary position by a command from the outside in a plane perpendicular to the optical axis of the projection lens 12. Wafer stage 1
The moving mechanism 3 can irradiate the illumination light IL that has passed through the projection lens 12 to a predetermined position on the silicon wafer 15.

In the exposure step, when the positioning of the wafer stage 13 is completed, the illumination light IL
And the light is reduced by the projection lens 12 and projected onto the silicon wafer 15 as a 1/5 line drawing of the circuit pattern drawn on the reticle 16, and the silicon wafer 1
Exposure of the photosensitive agent applied on 5 is performed. When the exposure process is completed, the wafer stage 13 is driven again to perform positioning, and exposure is performed. By repeating the positioning and exposure processes, the circuit pattern of the IC is reduced and projected on the silicon wafer 15.

Hereinafter, the operation of the air conditioner 50 and the active silencer 90 will be described. The air conditioner 50 blows clean air to the temperature control chamber 30 in order to control the temperature in the temperature control chamber 30. This keeps the air inside the temperature control chamber 30 constant and clean, preventing a decrease in exposure accuracy due to a temperature change, and preventing a decrease in exposure accuracy due to dust. Further, in order to prevent low frequency noise generated from the air conditioner 50 from diffusing into the temperature control chamber 30, the temperature control chamber 30 and the active noise reduction device 90 mounted near the air conditioner 50 are used.
Keep the sound pressure level inside.

FIG. 2 is a diagram for explaining the principle of active silencing. On the air conditioner 50 side of the duct 60, the first microphone 91 collects noise NS from the air conditioner 50.
The signal processing device 95 generates a signal having a waveform shifted in phase by a predetermined amount with respect to the noise waveform based on the detection signal from the first microphone 91,
Generates a sound wave SW for canceling the noise NS based on a signal from the signal processing device 95. As a result, the noise NS is hardly detected by the second microphone 92.

The principle of operation of the active silencer 90 will be described more conceptually. A sound wave emitted from a noise source (a blower or a refrigerator of an air conditioner) propagates through the duct 60 as a compression wave. In this case, the most important point of the operation principle is that the propagation speed of the sound wave in the air is much slower (by an order of magnitude) than the speed of the electric signal. That is, the noise signal propagated downstream from the location where the noise NS is detected (the location of the first microphone 91) and reaches the location where the noise is to be eliminated, and is picked up by the first microphone 91 within the signal processing device. Waveform processing is performed at 95, and a sound having the same amplitude and opposite phase as the propagation sound is generated from the speaker 97. The cancellation sound (sound wave SW) from the speaker 97 and the duct 6
By causing the noise NS that has transmitted 0 to interfere with each other, the noise can be positively canceled at the target point at the exit of the duct 60 (the position of the second microphone 92). When there is a distance between the first microphone 91 and the speaker 97, it is necessary to perform phase compensation due to this distance, and the signal processing device 95 shifts the phase of the noise signal to a value different from 180 °. A signal needs to be generated.

FIG. 3 shows how the air conditioner 50 is turned on and off.
5 is a graph showing how the noise in the temperature control chamber 30 changes. The horizontal axis indicates the frequency of the noise, and the vertical axis indicates the sound pressure level (SPL). When measuring noise, a sound level meter capable of measuring up to an extremely low frequency was used. In this measurement, the temperature control chamber 30 which is considered to affect the measurement is used.
The large-sized air conditioner that blows into the clean room where is installed is stopped, and the influence of noise entering from outside the temperature control chamber 30 was measured as much as possible. As is clear from the graph, an increase in the sound pressure level of about 15 dB is recognized by operating the air conditioner 50 as compared to when the air conditioner 50 is turned off. In particular, extremely low noise outside the audible range (low-frequency vibrations transmitted as compression waves in the air)
The difference gradually increases from around 3 Hz, which is
It can be seen that the sound pressure level reaches about 80 dB around Hz. Compared to the case where the air conditioner 50 is stopped, this low frequency noise is considered to be mainly caused by the air conditioner 50, and in particular, the blower 53 and the heat exchanger (refrigerator) 51 in the air conditioner 50 It is considered to be noise generated by

FIG. 4 shows the result of a simulation of how much the low-frequency air vibration of FIG. 3 induces vibration in the exposure apparatus system installed on the vibration isolation table 20.
Here, the horizontal axis indicates the vibration frequency (Hz), and the vertical axis indicates the vibration acceleration (m / s ² ). Vibration isolation table 20 and independent foundation 40
Above, the vibration frequency is 6-100Hz, 7-13mg
Al vibration acceleration is generated.

The vibration isolation table 20 on which the exposure apparatus main body 10 is installed has a vibration isolation function, and the vibration acceleration on the vibration isolation table 20 is considered to be about 0.7 mgal at the maximum.
The value of 0.7 mgal as a normally considered vibration acceleration value is considered to be an extremely small value having almost no influence. However, it is assumed that a fine processing or an exposure which is set on the assumption that a measurement at a λ / 10000 level is performed. For a device or an interferometer, the value has a meaning. Further, the value of the vibration acceleration of 0.7 mgal is induced only by noise, and in fact, floor vibration transmitted from the ground is also added to this value. It turns out that the situation is severe and some measures are needed.

FIG. 5 is a graph showing the relationship between the frequency of noise and the sound pressure level reaching the vibration isolation table 20. As is clear from the graph, when sound is silenced using the active silencer 90, the sound pressure level is set to 10 dB.
１５15 dB can be reduced. That is, the value of the vibration acceleration on the vibration isolation table 20 generated due to the noise from the air conditioner 50 can be suppressed to about 1/5 to 1/7. Therefore, the vibration level caused by noise can be reduced to 0.1 mgal or less.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the active silencer 90 is incorporated in the exposure apparatus system. To prevent vibration from occurring.

[0042]

As is apparent from the above description, according to the air conditioning system of the present invention, the control unit generates sound waves for canceling the noise detected by the noise detection device from the sound wave source. The resulting vibration can be prevented from being transmitted into the chamber. Therefore, precise measurement and processing can be performed in an air-conditioned atmosphere with little vibration. Machine tools that are expected to become even more precise in the future,
An extremely effective environment can be provided for a measurement instrument system such as an interferometer and a semiconductor-related exposure apparatus system.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an exposure apparatus system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation of an active silencer incorporated in the system of FIG.

FIG. 3 is a graph illustrating the effect of air conditioning noise in a chamber.

FIG. 4 is a graph illustrating a simulation result of vibration acceleration on a device base.

FIG. 5 is a graph illustrating the effect of noise in a chamber when the active silencer is operated.

FIG. 6 is a schematic configuration diagram of a conventional reduction projection exposure system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Exposure apparatus main body 12 Projection lens 13 Wafer stage 17 Illumination light source 20 Vibration isolation table 30 Temperature control chamber 40 Independent foundation 50 Air conditioner 51 Heat exchanger 53 Blower 60 Duct 65 Filter 71 Support 70 Floor 80 Buffer material 90 Active noise reduction device 91 First 1 microphone 92 second microphone 95 signal processing device 97 speaker 98 servo-type vibration detection sensor

Claims (3)

[Claims] 1. An air conditioning system comprising an air conditioner, a chamber, and a duct connecting the air conditioner and the chamber, wherein a noise detection device arranged in one of the duct and the air conditioner to detect noise. And a sound source arranged in one of the duct and the air conditioner to generate sound waves, and a control device configured to generate, from the sound source, sound waves for canceling noise detected by the noise detection device. An air conditioning system characterized by that: 2. An exposure apparatus system comprising: an air conditioner; a chamber containing an exposure apparatus main body for exposing a pattern on an original onto a photosensitive substrate; and a duct connecting the air conditioner and the chamber. A noise detection device that is disposed in any one of the air conditioners and detects noise, a sound source that generates a sound wave that is disposed in any one of the duct and the air conditioner, and is detected by the noise detection device An exposure apparatus system, further comprising: a control device configured to generate a sound wave for canceling noise from the sound source. 3. An interferometer system comprising an air conditioner, a chamber containing an interferometer main body for optically measuring the shape of an object, and a duct connecting the air conditioner and the chamber. A noise detection device that is disposed on one of the air conditioners and detects noise, a sound source that generates a sound wave that is disposed on one of the duct and the air conditioner, and a noise that is detected by the noise detection device. A controller for generating a canceling sound wave from the sound source.