JP2004063547A - Aligner under vacuum atmosphere - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aligner under a vacuum atmosphere with capability to utilize a vacuum associated equipment annexed to the aligner to cool a heat dissipating portion. <P>SOLUTION: A cooling jacket 31 is arranged in a circumference of the heat dissipating portion H in the aligner and peripheral equipments. An inside of the cooling jacket 31 is compartmentalized into inner and outer spaces 34, 36 by an inner wall 33, where there is provided automatic switching valves 38a, 38b. First, both the inner and the outer spaces 34, 36 are evacuated by the cooling jacket 31 to close the automatic switching valves 38a, 38b. Then, a gas is introduced only into the outer space 36 to open the automatic switching valves 38a, 38b and immediately after that, both the inner and outer spaces 34, 36 are re-evacuated, thus constituting one cycle so that the heat dissipating portion can be cooled. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exposure apparatus that forms a pattern by irradiating an energy beam on a sensitive substrate (such as a wafer) in a vacuum atmosphere. In particular, the present invention relates to an exposure apparatus under a vacuum atmosphere in which a heating unit (a part of a lens barrel, an actuator, or the like) can be cooled using a vacuum-related device (a vacuum pump or the like) attached to the exposure apparatus.
[0002]
Problems to be solved by the prior art and the invention
An EB (electron beam) exposure apparatus or an exposure apparatus using an ion beam or soft X-ray transfers an original pattern such as a reticle onto a sensitive substrate such as a wafer in a vacuum atmosphere. This type of exposure apparatus is provided with vacuum-related equipment (vacuum pump, vacuum valve, exhaust system, etc.) for evacuating the reticle vacuum chamber or the wafer vacuum chamber.
[0003]
By the way, in order to reduce the adverse effect of heat (such as the fluctuation of gas in the optical path), the conventional light exposure apparatus often includes a thermal air conditioner that covers the optical path with a cover or releases heat to the outside. On the other hand, in the current EB exposure apparatus, the above-mentioned fluctuation and the like are reduced by arranging the optical path of the interferometer in the vacuum chamber. However, when heat from a heat generating portion inside or outside the vacuum chamber (a part of the electron lens barrel, an actuator, or the like) is transmitted to the surroundings, device components such as the vacuum chamber may be thermally deformed and adversely affect exposure accuracy. is there. On the other hand, if a cooling system or the like for the heat-generating portion is additionally provided to prevent thermal deformation, it is not preferable because the device becomes complicated and the cost increases.
[0004]
SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and uses a vacuum-related device (such as a vacuum pump) attached to an exposure apparatus to generate a heat-generating portion (a part of a lens barrel or an actuator). An object of the present invention is to provide an exposure apparatus under a vacuum atmosphere capable of performing cooling.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a first exposure apparatus under vacuum atmosphere of the present invention is an exposure apparatus that irradiates an energy beam on a sensitive substrate in a vacuum atmosphere to form a pattern, and the exposure apparatus and peripheral equipment A cooling jacket disposed around the heat-generating portion, wherein a gas is introduced into and exhausted from the internal space of the cooling jacket, and the heat-generating portion is cooled by utilizing the adiabatic expansion action of the gas.
[0006]
In this exposure apparatus, the heating section can be cooled by using a means for making the inside of the exposure apparatus a vacuum atmosphere (for example, related equipment such as a vacuum pump). Therefore, it is possible to reduce fluctuations and the like due to heat from the heat generating portion. Further, since it is not necessary to separately provide a cooling system for the heat-generating portion, it is possible to avoid complication of the device and an increase in cost.
[0007]
In the first exposure apparatus under a vacuum atmosphere of the present invention, the internal space of the cooling jacket is partitioned into two inner and outer chambers, and an on-off valve is provided at a partition between the two inner and outer chambers. By evacuating both, closing the on-off valve, then introducing gas only into the outer chamber, opening the on-off valve, and immediately thereafter, evacuating both the inner and outer chambers again, the heat generating unit is turned off. Can be cooled.
In this case, first, both the inner and outer chambers are evacuated to lower the temperature, and the heating element in the inner space is cooled. Next, by closing the on-off valve to shut off the inner and outer chambers and introducing gas only to the outer chamber, the pressure in the outer chamber increases. Then, immediately after opening the on-off valve, the inside and outside chambers are evacuated again to lower the temperature, and the heating element in the internal space is cooled. At this time, the first evacuation and the second evacuation that cause a temperature drop in the room are equivalent to constitute a cooling cycle.
[0008]
A second exposure apparatus under a vacuum atmosphere of the present invention is an exposure apparatus that irradiates an energy beam onto a sensitive substrate in a vacuum atmosphere to form a pattern, and is arranged around a heating unit of the exposure apparatus and peripheral equipment. Further, a heat insulating jacket and a vacuum space are provided to insulate the heat from the heat generating portion from transmitting to the surroundings.
[0009]
In this exposure apparatus, heat transfer from the heat generating portion is blocked by the heat insulating jacket and is not transmitted to the surroundings, so that thermal deformation of the exposure apparatus can be reduced. As a result, the possibility of fluctuation of exposure or the like can be reduced.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, description will be made with reference to the drawings.
First, an outline of the configuration of the entire electron beam exposure apparatus and the image forming relationship will be described with reference to FIG.
FIG. 4 is a diagram schematically showing a configuration of an electron beam exposure apparatus (an example of a division transfer system).
The electron gun 1 arranged at the uppermost stream of the optical system emits an electron beam downward. A condenser lens 2 and an illumination lens 3 are provided below the electron gun 1, and an electron beam illuminates the reticle 10 through these lenses 2 and 3.
[0011]
Although not shown, an illumination beam shaping aperture, a blanking deflector, a blanking aperture, an illumination beam deflector, and the like are arranged in the illumination optical system having these lenses 2 and 3 as main components. . The illumination beam IB formed in the illumination optical system is sequentially scanned on the reticle 10 to illuminate each subfield of the reticle 10 within the field of view of the illumination optical system.
[0012]
The reticle 10 has many subfields and is mounted on a movable reticle stage 11. By moving the reticle stage 11 in a plane perpendicular to the optical axis, each subfield on the reticle extending over a wider range than the field of view of the illumination optical system is illuminated.
[0013]
Below the reticle 10, a first projection lens 15, a second projection lens 19, and a deflector 16 (16-1 to 16-6) used for aberration correction and image position adjustment are provided. The electron beam passing through one subfield of the reticle 10 is imaged at a predetermined position on a wafer (sensitive substrate) 23 by the projection lenses 15 and 19 and the deflector 16. An appropriate resist is applied on the wafer 23, a dose of an electron beam is given to the resist, and the pattern on the reticle 10 is reduced (for example, １ ／) and transferred onto the wafer 23.
[0014]
The point at which the reticle 10 and the wafer 23 are internally divided at the reduction ratio is crossover C. O. Are formed, and a contrast opening 18 is provided at the crossover position. The opening 18 blocks the electron beam scattered by the non-pattern portion of the reticle 10 from reaching the wafer 23.
[0015]
The wafer 23 is placed on a wafer stage 24 that can move in the X and Y directions via an electrostatic chuck. By synchronously scanning the reticle stage 11 and the wafer stage 24 in directions opposite to each other, each part of the device pattern extending beyond the field of view of the projection optical system can be sequentially exposed.
[0016]
Next, a configuration related to a cooling jacket of the exposure apparatus according to the present invention will be described.
FIG. 1 is a plan view schematically showing the configuration of a cooling jacket attached to an exposure apparatus according to the present invention.
FIGS. 2A to 2D are views for explaining a cooling cycle using the cooling jacket of FIG.
FIG. 3 is a conceptual diagram showing the entire configuration of the exposure apparatus according to the present invention.
[0017]
An illumination optical system barrel 30 is shown above the exposure apparatus shown in FIG. The electron gun 1, the condenser lens 2, the illumination lens 3 (see FIG. 4) and the like are arranged in the illumination optical system barrel 30. The inside of the lens barrel 30 is evacuated by a vacuum pump (not shown). A cooling jacket (pressure vessel or the like) 31 is arranged around the illumination optical system lens barrel 30. The electron gun 1 and the like are cooled by the cooling jacket 31.
[0018]
Here, the cooling jacket 31 will be described with reference to FIG.
As shown in FIG. 1, the cooling jacket 31 has a double structure with a rectangular cross section having an inner wall portion 33 and an outer wall portion 35 outside the inner wall portion 33. In this embodiment, the cross section is square, but another shape may be used. The inner and outer wall portions 33 and 35 and a partition portion 37 described later are formed of a material having a high heat insulating property such as ceramics, for example. An inner space 34 is formed inside the inner wall portion 33. The inner wall portion 33 serves to partition the inside of the cooling jacket 31 into two inner and outer chambers, and also serves as a heat insulating jacket that does not transmit the heat of the internal heating element H (in this case, the illumination optical system barrel 30) to the surroundings. . An outer space 36 is formed between the inner and outer wall portions 33 and 35. Between the inner and outer wall portions 33 and 35, there are provided two partition portions 37 that further partition the outer space 36 into two chambers (36A and 36B).
[0019]
Two automatic opening / closing valves 38a and 38b are incorporated in the inner wall portion 33 so as to correspond to the outer spaces 36A and 36B, respectively. On the other hand, automatic opening / closing valves 39a and 39b are also incorporated in each of the two partition portions 37. Further, a supply / exhaust pipe 41 is connected to the outer space 36A side of the outer wall 35 (see also FIG. 3). An automatic open / close valve 42 is incorporated in the supply / exhaust pipe 41. The supply / exhaust pipe 41 is connected to related devices for setting the inside of the exposure apparatus to a vacuum atmosphere, such as a vacuum pump for evacuating the optical system barrel and a vacuum pump for evacuating the vacuum chamber described later. . By the operation of the vacuum-related equipment, gas can be introduced and discharged into the inner and outer spaces 34 and 36 of the cooling jacket 31.
[0020]
A heating element H (in this case, the illumination optical system barrel 30) is arranged in the inner space 34 of the cooling jacket 31. On the outer periphery of the heating element H, a wall portion 32 made of a material having a high thermal conductivity such as steel is provided. Due to the wall portion 32, the heat of the heating element H is easily transmitted to the cooling jacket 31.
[0021]
A description will be given of a temperature change in the cooling jacket 31 during depressurization (during evacuation).
The gas introduced into the inner and outer spaces 34, 36 of the cooling jacket 31 is assumed to be the atmosphere. In this case, considering the adiabatic change of air, the following equation holds:
T2 = (P2 / P1) ^{(n-1) / n} × T1,
Here, T1: initial temperature (absolute temperature) in the cooling jacket,
T2: temperature after pressure reduction in the cooling jacket (absolute temperature),
P1: initial pressure (absolute pressure) in the cooling jacket,
P2: pressure after decompression in the cooling jacket (absolute pressure),
n: polytropic index (n = 1.4 in the case of air)
It is.
[0022]
Using this equation, the temperature change in the cooling jacket is determined.
First, when the internal pressure of the cooling jacket is reduced from the atmospheric pressure (0.1013 MPa) to the low vacuum region pressure (10 kPa),
When the temperature in the cooling jacket is 23 ° C. at atmospheric pressure, the pressure is reduced at −120 ° C.,
When the temperature in the cooling jacket is 50 ° C. at atmospheric pressure, the pressure is reduced at −106 ° C.,
The temperature drops as follows.
[0023]
Next, compressed air is introduced into the cooling jacket to increase the internal pressure to 0.3 MPa (initial pressure), and when the initial pressure is reduced to a low vacuum region pressure (10 kPa),
When the temperature in the cooling jacket is 23 ° C. at the initial pressure, the pressure is reduced at −161 ° C.,
When the temperature in the cooling jacket is 50 ° C at the initial pressure, -150 ° C at the time of decompression,
The temperature drops as follows.
[0024]
As shown in FIG. 3, an air pipe 43 and an automatic open / close valve 44 are connected to the cooling jacket 31 in addition to the above-described supply / exhaust pipe 41 and the automatic open / close valve 42. The air pipe 43 is a pipe for introducing compressed air used in a mechanism system (for example, a stage driving mechanism) of the exposure apparatus into the cooling jacket 31. The air pipe 43 may be omitted, and the atmosphere may be introduced into the cooling jacket 31. In the case where the compressed air is introduced from the air pipe 43, there is an advantage that the cooling capacity of the cooling jacket 31 is increased because the differential pressure is larger than that when the air is introduced.
[0025]
As shown in FIG. 3, a reticle vacuum chamber 50 is arranged below the illumination optical system barrel 30. In the reticle vacuum chamber 50, a reticle stage 11 on which the above-described reticle 10 is mounted is arranged. A vacuum pump 53 is connected to the vacuum chamber 50 via a chamber exhaust system 51. The chamber exhaust system 51 and the vacuum pump 53 can be used to evacuate the cooling jacket 31 described above. Although not shown in FIG. 3, the reticle vacuum chamber 50 is also connected to a reticle loader chamber and a reticle load lock chamber.
[0026]
The reticle vacuum chamber 50 and the reticle stage 11 are mounted on the main body 45. At the center of the main body 45, a projection optical system barrel 60 is supported. The above-described first projection lens 15 and second projection lens 19 (see FIG. 4) are arranged in the projection optical system barrel 60. The inside of the lens barrel 60 is evacuated by a vacuum pump (not shown).
[0027]
Below the main body 45, a wafer vacuum chamber 70 is suspended. In the wafer vacuum chamber 70, a wafer stage 24 on which the above-described wafer 23 is mounted is arranged. A wafer exhaust system and a vacuum pump (not shown) are also connected to the wafer vacuum chamber 70, similarly to the reticle vacuum chamber 50 described above. These chamber exhaust system and vacuum pump can be used as vacuum-related equipment for evacuating the cooling jacket 31 described above. Although not shown in FIG. 3, the wafer vacuum chamber 70 is also connected to a wafer loader chamber, a wafer load lock chamber, and the like.
[0028]
The main body 45 is mounted on an anti-vibration table 78 based on a base plate 77 via an air mount 75. The anti-vibration table 78 includes an actuator 79 that is driven in cooperation with the air mount 75. At the location where the actuator 79 is built in, a cooling jacket 31 ′ similar to the above-described cooling jacket 31 (see FIG. 1) is arranged around the vibration isolating table 78 (only the left side is shown in FIG. 3). ing). The actuator 79 is cooled by the cooling jacket 31 '. That is, the heating element H in FIG. 1 is the actuator 79 in this case.
[0029]
Next, the operation (cooling cycle) of the cooling jacket 31 will be described with reference to FIG.
In FIG. 2, the valves in the “open” state are shown in white for the automatic on-off valves 38 a, 38 b, 39 a, 39 b and 42 described above with reference to FIG. 1, and the valves in the “closed” state Is shown in black. In addition, a portion where gas is introduced into the inner and outer spaces 34 and 36 is indicated by dots, and a portion where gas is discharged (evacuated) is indicated by white.
The heating element H in FIG. 2 is the illumination optical system barrel 30 and the actuator 79 described above.
[0030]
The cooling of the heating element H using the cooling jacket 31 is performed as follows.
First, as shown in FIG. 2A, all the automatic opening / closing valves 38a, 38b, 39a, 39b and 42 of the inner wall 33, the outer wall 35 and the supply / exhaust pipe 41 are opened, and the cooling jacket is connected to the supply / exhaust pipe 41. Atmosphere is introduced into 31. Since the automatic on-off valves are all open, the inner and outer spaces 34 and 36 of the cooling jacket 31 communicate with each other, and the atmosphere is introduced into both of them. The internal pressure at this time is about 100 kPa.
When the air pipe 43 and the automatic opening / closing valve 44 are provided, compressed air can be introduced instead of the atmosphere.
[0031]
Next, as shown in FIG. 2B, the inside of the cooling jacket 31 is evacuated to about 50 kPa, and only the automatic opening / closing valve 42 of the supply / exhaust pipe 41 is closed. As described above, the evacuation of the cooling jacket 31 is performed by the operation of the vacuum-related equipment of the exposure apparatus. Due to this evacuation, a temperature drop occurs in the inner and outer spaces 34 and 36 of the cooling jacket 31, and the heating element H in the inner space 34 is cooled through the wall 32.
[0032]
Next, as shown in FIG. 2 (C), the automatic open / close valves 38a and 38b of the inner wall 33 are closed while the automatic open / close valve 42 of the supply / exhaust pipe 41 is kept closed. Thus, the inner space 34 and the outer space 36 in the cooling jacket 31 are shut off, and become independent spaces.
[0033]
Next, as shown in FIG. 2D, the automatic opening / closing valve 42 of the supply / exhaust pipe 41 is opened while the automatic opening / closing valves 38a, 38b of the inner wall portion 33 are kept closed. Then, in the cooling jacket 31, only the outer space 36 is opened to the atmosphere, and the internal pressure rises. At this time, the internal pressure of the internal space 34 is about 50 kPa, and the internal pressure of the external space 36 is about 100 kPa, and the temperature inside the external space 36 increases due to the differential pressure. However, since the inner and outer spaces 34 and 36 are partitioned by the inner wall 33 made of a heat insulating material such as ceramics, heat transfer to the heating element H at an increased temperature is small.
[0034]
Then, immediately after this operation, the automatic opening / closing valves 38a and 38b of the inner wall portion 33 are opened, and the internal and external spaces 34 and 36 are communicated to evacuate the internal and external spaces to about 50 kPa. Is closed. This state is the state of FIG. 2B described above. The evacuation at this time causes a temperature drop in the inner and outer spaces 34 and 36 of the cooling jacket 31, and the heating element H in the inner space 34 is cooled via the wall 32. The first evacuation described above and the second evacuation this time are equivalent to constitute a cooling cycle of the heating element H.
[0035]
【The invention's effect】
As is apparent from the above description, according to the present invention, the heat-generating portion (a part of the lens barrel, the actuator, etc.) is cooled using the vacuum-related equipment (vacuum pump, etc.) attached to the exposure apparatus. be able to.
[Brief description of the drawings]
FIG. 1 is a plan view schematically showing a configuration of a cooling jacket attached to an exposure apparatus according to the present invention.
FIG. 2 is a diagram for explaining a cooling cycle using the cooling jacket of FIG.
FIG. 3 is a conceptual diagram showing an overall configuration of an exposure apparatus according to the present invention.
FIG. 4 is a diagram schematically illustrating a configuration of an electron beam exposure apparatus (an example of a division transfer method).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Reticle 23 Wafer 30 Illumination optical system lens barrel 31, 31 'Cooling jacket 32 Wall part 33 Inner wall part 34 Inner space 35 Outer wall part 36 (36A, 36B) Outer space 37 Partition part 38a, 38b, 39a, 39b, 42, 44 Automatic open / close valve 41 Supply / exhaust pipe 43 Air pipe 45 Main body 50 Reticle vacuum chamber 51 Chamber exhaust system 53 Vacuum pump 60 Projection optical system barrel 70 Wafer vacuum chamber 75 Air mount 77 Base plate 78 Vibration isolator 79 Actuator H Heating element

Claims (3)

An exposure apparatus that forms a pattern by irradiating an energy beam on a sensitive substrate in a vacuum atmosphere,
Comprising a cooling jacket arranged around a heating unit of the exposure apparatus and peripheral equipment,
An exposure apparatus under a vacuum atmosphere, characterized in that a gas is introduced into and discharged from an internal space of the cooling jacket, and the heat generating portion is cooled by utilizing adiabatic expansion action of the gas. The internal space of the cooling jacket is partitioned into two inner and outer chambers,
An on-off valve is provided in the partition between the inner and outer chambers,
A cycle in which both the inner and outer chambers are evacuated and the on / off valve is closed, then gas is introduced only into the outer chamber, and then the on / off valve is opened, and immediately thereafter, both the inner and outer chambers are again evacuated, 2. The exposure apparatus according to claim 1, wherein the heating unit is cooled. An exposure apparatus that forms a pattern by irradiating an energy beam on a sensitive substrate in a vacuum atmosphere,
An exposure apparatus under a vacuum atmosphere, comprising: a heat insulating jacket disposed around a heating section of the exposure apparatus and peripheral equipment for heat insulation so that heat from the heating section is not transmitted to the surroundings; and a vacuum space.

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