JP4502366B2 - Exposure equipment - Google Patents

Description

  The present invention relates to a noise reduction technique for a temperature control system in which, for example, in an exposure apparatus used for semiconductor device manufacture, an inert gas is appropriately temperature-controlled and circulated in a sealed chamber.

  The light source of an exposure apparatus used for semiconductor manufacturing or the like has become shorter in wavelength with the finer exposure pattern. That is, the exposure light source has shifted from i-line to excimer laser, and the laser light source has also shifted from KrF to ArF. Currently, the use of F2 laser is being studied in order to satisfy the demand for further miniaturization.

  In order to construct an exposure system using an F2 laser as a light source, it is necessary to take measures against energy attenuation of exposure light. Since F2 laser light is absorbed by moisture, oxygen, organic gas, etc. contained in the atmosphere, a conventional exposure apparatus cannot be applied as it is.

  Therefore, as a means for dealing with the F2 laser, a method is conceivable in which the entire space through which the exposure light passes is sealed with a partition, and the space is filled with an inert gas such as nitrogen. However, even in this method, the space in which the wafer and reticle are arranged has a large amount of heat generated by the linear motor of the stage device as a heat source, and in order to maintain the positional accuracy, it is not intended to remove fluctuations in the temperature in the space. An active gas temperature control circulation system (hereinafter, temperature control system) is required.

  FIG. 5 is a diagram illustrating a conventional exposure apparatus and its temperature control system.

  As shown in FIG. 5, a wafer space 21 and a reticle space 22 inside the main body of the exposure apparatus are surrounded by a chamber 23, and the inside of the chamber 23 is a sealed space. A wafer stage 37 that moves and positions the wafer W relative to the reticle R in the wafer space 21, and a reticle stage 38 that moves and positions the reticle R relative to the wafer W in the reticle space 22. Each is arranged. A projection optical system 39 is disposed between the wafer space 21 and the reticle space 22 to project the circuit pattern on the reticle R onto the wafer W using laser light.

  Each of the spaces 21 and 22 is provided with a gas blowing part 24 for blowing out an inert gas adjusted to an appropriate temperature and free from contaminants such as dust and dust, and a collecting part 25 for collecting the gas. ing. In addition, in order to circulate the inert gas inside the chamber 23, a circulation device 26 is installed, and the recovery unit 25 is connected via the supply duct 27 and the blowout unit 24 and the return duct 28, respectively.

  The circulation device 26 includes internal devices arranged in the order of the cooler 29, the blower 30, the filter 31, and the heater 32 from the upstream side with respect to the flow direction of the inert gas.

  The inert gas recovered from the interior of the wafer space 21 and the reticle space 22 via the return duct 28 absorbs the heat generated in the interior of the wafer space 21 and the reticle space 22. Heat exchanged. The cooled inert gas is sent to the filter 31 to remove contaminants (contamination) such as dust and dirt.

  Here, the filter 31 is composed of a chemical filter that removes ammonia having high resist reactivity, an activated carbon filter that removes siloxane and other organic gases that degrade the optical member, and a ULPA filter that removes particles. The cooled and contaminated inert gas is further heated by the heater 32 and circulated to the gas blowing section 24. The power source for this circulating fluid transfer is the blower 30.

  Further, an inert gas having a high purity is injected into the wafer space 21 and the reticle space 22 from the inert gas injection valve 33 to maintain the concentration of the inert gas in the wafer space 21 and the reticle space 22, and the discharge valve 34. By discharging a predetermined amount of gas through the throttle valve 35, the internal pressure of the wafer space 21 and the reticle space 22 is increased to prevent the outside air from entering.

The temperature adjustment of the inert gas is performed by the temperature sensor 36 detecting the temperature of the inert gas, the signal is input to the temperature controller 33, and the output of the heater 32 is controlled by PID feedback control or the like. .
Japanese Patent Application Laid-Open No. 09-246140 JP 09-260279 A

  As described above, when the inert gas is circulated in a sealed space, there is no escape place for the sound generated by the blower, etc., so there is a large pressure fluctuation reflected in the chamber, and the projection optics performing vibration isolation There is a problem that the vibration caused by the pressure fluctuation is applied to the stages 38 and 39 of the system, the wafer and the reticle, resulting in deterioration of the imaging performance of the optical system and the positioning accuracy of the drive system.

  The present invention has been made in view of the above problems, and reduces the propagation of sound generated by circulating a temperature-adjusted gas to the chamber, thereby preventing the vibration isolation performance from deteriorating due to pressure fluctuations. The purpose is to provide technology that can be used.

In order to achieve the above object, an exposure apparatus of the present invention has a chamber, and in the exposure apparatus that exposes an object in the chamber, a blower that blows a temperature-adjusted gas, and an upstream side of the chamber. A supply path for connecting the temperature-adjusted gas to the chamber, and a recovery path connected to the downstream side of the chamber for recovering the gas supplied into the chamber. wherein a circulation means for circulating a temperature control gas, wherein the supply-side muffler provided in the supply path, provided with the recovery side muffler on the recovery path.

  Moreover, as a more preferable aspect of the above apparatus, the apparatus further includes a stage apparatus as a heat source for positioning the original and the substrate by moving them to a desired relative position.

  As described above, according to the present invention, by reducing the propagation of sound generated by a blower or the like to a chamber, for example, to a projection optical system disposed in the chamber, each stage device of a wafer and a reticle, or the like. Therefore, it is possible to reduce the vibration caused by the pressure fluctuation, and as a result, the imaging performance of the optical system and the positioning system of the drive system can be improved.

Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating an exposure apparatus and its temperature control system according to the first embodiment of the present invention. Moreover, in the following description, the same number is attached | subjected to the part which is common in the conventional structure demonstrated in FIG. 5, and description is abbreviate | omitted.

  As shown in FIG. 1, a wafer space 21 and a reticle space 22 inside the main body of the exposure apparatus are surrounded by a chamber 23, and the inside of the chamber 23 is a sealed space filled with an inert gas in a desired atmosphere. Each of the spaces 21 and 22 is provided with a gas blowing part 24 for blowing out an inert gas adjusted to an appropriate temperature and free from contaminants such as dust and dust, and a collecting part 25 for collecting the gas. ing. Further, in order to circulate the inert gas inside the chamber 23, a circulation device 26 is installed, and the blowing unit 24 is connected via the supply side silencing duct 1 and the recovery unit 25 is connected via the return side silencing duct 2. The The supply-side silencing duct 1 is provided in the vicinity of the upstream portion of the blowing portion 24 of the chamber 23, and the return-side silencing duct 2 is provided in the vicinity of the downstream portion of the collecting portion 25 of the chamber 23. The silencer ducts 1 and 2 may be provided in at least one of the upstream and downstream of the chamber 23.

  In the above configuration, the blower 30 provided in the circulation device 26 serves as a noise generation source, but noise propagation from the supply side and the return side to the chamber 23 is reduced by the supply side silencing duct 1 and the return side silencing duct 2.

  Next, a specific structure and a silencing method of the silencing duct will be described.

  FIG. 2 shows the structure of the silencer duct according to the first embodiment. The silencer ducts 1 and 2 are substantially the same as the inflatable part 3 and the inflatable part 3 that expands rapidly on the most upstream side in the gas flow direction. The expansion chamber 4 having the same diameter and extending in the gas flow direction and the contraction portion 5 that rapidly contracts the diameter of the expansion chamber 4 function as a simple acoustic filter that uses the sound interference action. This acoustic filter has the effect of reducing the sound in the frequency band represented by the following formula 1, where L is the length of the expansion chamber 4, C is the speed of sound, and n is an arbitrary integer.

Frequency f = C (2n + 1) / 4L (1)
Therefore, when the specific frequency of the sound generated from a noise source such as a blower is self-evident, the effective length L of the silencer duct can be determined by Equation 1 above.

  In particular, when the sound source is a rotary fluid transport device such as a blower, the frequency f of the generated sound is expressed by the following equation 2 where the rotation speed is N (rpm) and the number of blades is Z.

f = NZ / 60 (2)
Further, if the cross-sectional area of each throat part of the inflating part 3 or the contracting part 5 is S1, and the cross-sectional area of the expansion chamber 4 is S2, the silencing effect increases as the area ratio m = S2 / S1 increases. It is shown by Formula 3.

Attenuation _{= 10Log 10 {1+ (m-} 1 / m) 2/4 · sin 2 (2πfL / C)} [dB] ··· (3)
According to this embodiment, it is possible to reduce the sound generated by a blower or the like with a simple structure in which the expansion chamber 4 is provided. In addition, as shown in FIG. 2, by providing the expansion / contraction part 12 so that the length L of the expansion chamber 4 can be adjusted, it is possible to tune the attenuation effect for a desired silencing frequency.
[Second Embodiment]
FIG. 3 is a diagram illustrating an exposure apparatus and its temperature control system according to the second embodiment of the present invention. Moreover, in the following description, the same number is attached | subjected to the part which is common in the structure of 1st Embodiment demonstrated in the said FIG. 1, and description is abbreviate | omitted.

  In the second embodiment, as shown in FIG. 3, the blowout part 24 is connected via the supply-side silencer duct 6 and the recovery part 25 is connected via the return-side silencer duct 7, respectively. Thus, the noise propagation from the supply side and the return side to the chamber 23 is reduced by the supply side silencer duct 6 and the return side silencer duct 7.

  Next, a specific structure and a silencing method of the silencing duct will be described.

  FIG. 4 shows the structure of the silencer duct of the second embodiment. The silencer ducts 6 and 7 are divided into two paths, a first branch path 9 and a second branch path 10, which have different lengths with respect to the gas flow direction. A bifurcated branch section 8 and a junction section 11 where the first and second paths 9 and 10 merge again are provided, and sound interference action is achieved by making the first path 9 and the second path 10 different in length. The mute function that uses is generated. The silencer ducts 6 and 7 may also be provided in at least one of the upstream and the downstream of the chamber 23 as in the first embodiment.

  If the length of the first path 9 is L1, the length of the second path 10 is L2, the speed of sound is C, and an arbitrary integer is n, the sound in the frequency band represented by the following equation 4 is reduced.

Frequency f = C (2n + 1) / 2 (L1-L2) (4)
Therefore, when the specific frequency of the sound generated from a noise source such as a blower is obvious, the effective lengths L1 and L2 of the first path 9 and the second path 10 of the silencer duct can be determined by the above equation 4. .

  Further, as described above, when the sound source is a rotary fluid transport device such as a blower, the frequency of the generated sound is expressed by the above equation 2 where the rotation speed is N (rpm) and the number of blades is Z. .

  According to this embodiment, it is possible to reduce sound generated by a blower or the like by causing sound interference by two piping paths having different lengths.

  In each of the above embodiments, as shown in FIG. 4, the first path 9 is expanded and contracted in the gas flow direction, and the length L1 in the direction is made variable so that the length L1 is variable, thereby providing the length. By varying L1, it is possible to tune the attenuation effect for the desired mute frequency.

  As described above, according to each embodiment, the propagation of sound generated by a blower or the like to the sealed chamber is reduced, and the pressure applied to each stage of the projection optical system, the wafer, the reticle, and the like disposed in the sealed chamber Vibration caused by fluctuations can be reduced, and as a result, the imaging performance of the optical system and the positioning accuracy of the drive system can be improved.

It is a figure which illustrates the exposure apparatus of 1st Embodiment which concerns on this invention, and its temperature control system. It is a figure explaining the composition of the silencer duct of a 1st embodiment. It is a figure which illustrates the exposure apparatus and temperature control system of 2nd Embodiment which concern on this invention. It is a figure explaining the structure of the silencer duct of 2nd Embodiment. It is a figure which illustrates the conventional exposure apparatus and its temperature control system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Supply side muffler duct 2 Return side muffler duct 3 Expansion part 4 Expansion chamber 5 Shrink part 6 Supply side muffler duct 7 Exhaust side muffler duct 8 Branch part 9 1st branch path 10 2nd branch path 11 Merging part 12 Telescopic part 21 Wafer Space 22 Reticle space 23 Chamber 24 Temperature control gas outlet 25 Recovery unit 26 Circulator 27 Supply duct 28 Return duct 29 Cooler 30 Blower 31 Filter 32 Heater 33 Inert gas injection valve 34 Drain valve 35 Throttle valve 36 Temperature sensor 37 Wafer stage 38 Reticle stage 39 Projection optical system L Expansion chamber length C Sound velocity n Arbitrary integer f Frequency N Number of rotations Z Number of blades L1 First path length L2 Second path length W Wafer R Reticle

Claims (6)

In an exposure apparatus that has a chamber and exposes an object in the chamber,
A blower for blowing temperature-adjusted gas, a supply path connected to the upstream side of the chamber and supplying the temperature-adjusted gas to the chamber, and connected to the downstream side of the chamber and supplied into the chamber have been and a recovery path for recovering the gas, and a circulating means for circulating said temperature regulated gas through the chamber,
An exposure apparatus comprising: a supply-side silencer in the supply path; and a collection-side silencer in the recovery path. The exposure apparatus further includes a laser light source, and is an exposure apparatus that exposes an original plate or a substrate in the chamber using laser light from the laser light source,
The exposure apparatus according to claim 1, wherein the temperature-adjusted gas is an inert gas. The supply-side silencing means and the recovery-side silencing means include an expansion portion that expands on the most upstream side with respect to the flow direction of the temperature-adjusted gas or the recovered gas, and the gas having the same diameter as the expansion portion. The exposure apparatus according to claim 1, further comprising: an expansion chamber extending in a flow direction, and a contraction portion having a diameter reduced with respect to the expansion chamber, and having a function of muting the sound by causing interference. The supply-side silencer and the recovery-side silencer include a branch portion having a different length with respect to the flow direction of the temperature-adjusted gas or the collected gas, and a junction portion where these branch portions merge, The exposure apparatus according to claim 1, wherein the exposure apparatus has a function to mute by causing interference. The supply-side silencing means and the recovery-side silencing means include an expansion / contraction section that expands and contracts in the flow direction of the temperature-adjusted gas or the recovered gas and makes the length in the direction variable, and interferes with the length. 5. The exposure apparatus according to claim 1, wherein the frequency of the sound can be adjusted.   The exposure apparatus according to claim 2, further comprising a stage device as a heat source for relatively moving the original and the substrate.

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