JP2002198296A - Aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply a gas in which an impurity is sufficiently removed. SOLUTION: Supply devices 43 and 48 which supply a gas (nitrogen, dry air, and the like) through which an illumination light IL transmits are provided to gas supply chambers 14, 20A, 20B, PL, or 34 so formed as to contain at least a space which contains at least a partial optical path of the illumination light IL or a space adjacent to it. Line filter units 41 and 46 are interposed in gas supply paths 39, 39A-39D, 42, 45, and 47 between the supply devices 43 and 48 and the gas supply chambers. A first filter (57) for removing at least an inorganic material contained in the gas and a second filter (58) for removing at least an organic material contained in the gas are connected in series.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus used for transferring a mask pattern onto a substrate in a lithography process for manufacturing, for example, a semiconductor device, a liquid crystal display device, an image pickup device, a thin film magnetic head and the like. About.

[0002]

2. Description of the Related Art In a lithography process for manufacturing a semiconductor device, a substrate (such as a semiconductor wafer or the like) on which a photosensitive agent is applied through a mask (including a reticle) on which a pattern is formed by illumination light from a light source. An exposure apparatus is used that transfers an image of a pattern of a mask onto the substrate by exposing the photosensitive substrate). Illumination light from the light source is guided to the substrate via an optical system including a plurality of optical elements (lenses, mirrors, etc.). The optical system that constitutes the optical path from the light source to the mask is the illumination optical system and the optical system from the mask to the substrate. The optical system that constitutes the optical path leading to the optical path is generally called a projection optical system. The illumination light from the light source is guided to an alignment optical system used for various positionings.

When impurities (organic impurities and inorganic impurities) are present in the optical path of illumination light constituted by such an optical system, the energy of the illumination light is reduced and the surface of the optical element is impaired. Since a decrease in illuminance due to the adhesion may occur, a room defined to include a part of the optical path (for example, a case in which a light source is housed, a subchamber in which an illumination optical system is housed, and a mirror of a projection optical system) (Including a temperature control chamber that almost completely houses the cylinder and the exposure apparatus) with a purge gas such as clean dry air or high-purity nitrogen, and discharges gas containing impurities in those chambers to the outside. Then, replacement with the purge gas, that is, purging is performed.

[0004] Such a purge gas is supplied from a supply device having a compressor, a cylinder, and the like provided in a semiconductor manufacturing factory in which an exposure apparatus is installed, via a factory pipe.
Here, the purge gas immediately after being supplied from the supply device is:
Although it is clean with impurities removed according to predetermined specifications, its cleanliness may decrease due to the intrusion of outside air while flowing through factory piping and the like.

[0005] For this reason, a filter is interposed at the connection with the factory piping to remove impurities, so that a clean purge gas conforming to the specifications of the exposure apparatus can always be supplied.

As such a filter, a filter in which an impregnating agent is impregnated on activated carbon is employed. As the impregnating agent, a counter ion that causes a neutralization reaction with a target substance (substance to be removed) is used. In such a filter, activated carbon adsorbs and removes mainly organic substances in the purge gas,
The impregnating agent acts to remove inorganic substances by a chemical reaction (neutralization reaction). As a result, both the organic substance and the inorganic substance as impurities contained in the purge gas are removed.

[0007]

The conventional filter chemically removes inorganic substances as impurities contained in the purge gas by a neutralization reaction.
Such neutralization requires a certain amount of water.
However, since the amount of water contained in the purge gas is extremely small, there has been a problem that the inorganic substance may not be sufficiently removed.

Further, there is a limit to the removal capability of the line filter. For example, when a failure occurs in the purge gas supply device or when a break occurs in a factory piping, etc. In some cases, it becomes impossible to supply the purge gas. However, even in such a case, it is not preferable to keep supplying the purge gas because the environment of the chamber to be purged is positively deteriorated.

The present invention has been made in view of the above circumstances, and has as its object to supply a gas from which impurities have been sufficiently removed. It is another object of the present invention to be able to immediately stop the supply of a gas in the event that a gas that satisfies the specifications relating to the content of the impurity cannot be supplied.

[0010]

In the following description, in order to facilitate understanding, constituent elements of the present invention will be described with reference numerals shown in the drawings of the embodiments. Are not limited by these reference numerals.

1. An exposure apparatus according to the present invention for achieving the above object, in an exposure apparatus for exposing a substrate (W) with an exposure beam (IL), comprises: a space including at least a part of an optical path of the exposure beam; Supply device (43, 4) for supplying a gas through which the exposure beam passes to a gas supply chamber (14, 20A, 20B, PL, 34) defined so as to include at least one of the spaces arranged in a vertical direction.
8) and a gas supply path (39, 39A to 39D, 42, 45, 47) from the supply device to the gas supply chamber.
A first filter (57) provided therein for removing at least an inorganic substance contained in the gas; and a first filter (57) provided in a supply path of the gas for removing at least an organic substance contained in the gas. And a second filter (58).

According to the exposure apparatus of the present invention, the inorganic substance in the gas supplied to the gas supply chamber is mainly removed by the first filter, and the organic substance is mainly removed by the second filter. Both inorganic and organic impurities contained in the gas are sufficiently removed. Therefore, it is possible to sufficiently prevent a decrease in the illuminance of the exposure beam and the occurrence of illuminance unevenness.

In the exposure apparatus, a ceramic honeycomb filter to which an inorganic material is attached may be used as the first filter (57), and an activated carbon filter may be used as the second filter. Further, the first filter (57) and the second filter (58) can be arranged such that the first filter is located upstream and the second filter is located downstream with respect to the flow direction of the gas. As the inorganic substance removed by the first filter, ammonia (NH
₃ ), at least one of sulfur dioxide (SO ₂ ), nitric oxide (NO), nitrogen dioxide (NO ₂ ), and nitrous oxide (N ₂₀ ). Note that the first filter may have an ability to also remove organic substances.

When the gas supplied to the gas supply chamber is high-purity nitrogen gas, the first filter and the second filter
The impurity contained in the nitrogen gas passed through the filter has a concentration of 1 μg / m ³ or less for the total amount of the organic components,
The concentration of silicon-based material is 0.1 μg / m ³ or less, the concentration of ammonia is 0.2 μg / m ³ or less, the concentration of sulfur oxide is 0.2 μg / m ³ or less, and the concentration of nitrogen oxide is It is desirable that the concentration of water be 0.2 μg / m ³ or less and the dew point be -70 ° C. or less.

Further, when the gas supplied to the gas supply chamber is dry air, the first filter and the second
Impurities contained in the dry air passed through the filter, the concentration of the total amount of organic components is 5 μg / m ³ or less,
The concentration of silicon-based material is 0.1 μg / m ³ or less, the concentration of ammonia is 0.2 μg / m ³ or less, the concentration of sulfur oxide is 0.2 μg / m ³ or less, and the concentration of nitrogen oxide is It is desirable that the concentration of water be 0.2 μg / m ³ or less and the dew point be −30 ° C. or less.

In the exposure apparatus, a detection device (61, 62, 66, 6) for detecting the concentration of at least one of an organic substance and moisture contained in the gas flowing through the supply path.
7) and a control device (63) for stopping supply of gas by the supply device to the gas supply chamber when a detection result by the detection device exceeds a predetermined value.

2. An exposure apparatus according to the present invention for achieving the above object is an exposure apparatus that exposes a substrate (W) with an exposure beam (IL), wherein at least a part of an optical path of the exposure beam or an optical path adjacent to the optical path is provided. A gas supply chamber (14,
20A, 20B, PL, 34), a supply device (43, 48) for supplying a gas through which the exposure beam passes, and a gas supply path (3) from the supply device to the gas supply chamber.
9, 39A to 39D, 42, 45, 47) for detecting the concentration of at least one of an organic substance and moisture contained in the gas in the supply path (61, 6).
2, 66, 67) and a control device (63) for stopping supply of the gas by the supply device to the gas supply chamber when a detection result by the detection device exceeds a predetermined value. It is characterized by the following.

In this case, a gas supply path (39, 39A to 39A) from the supply device to the gas supply chamber is provided.
D, 42, 45, 47) and a filter (41, 46) for removing a light absorbing substance that absorbs the exposure beam (IL) contained in the gas. As the filters (41, 46), those having the same removal function as the first filter (57) and the second filter (58) can be adopted.

According to the present invention, the concentration of at least one of the organic substance and the moisture in the gas supplied to the exposure apparatus is detected, and if the detection result exceeds a predetermined value, the gas supply path is broken, Alternatively, the supply of gas is stopped on the assumption that a failure such as a failure of the supply device has occurred, so that a gas containing a large amount of impurities including water is prevented from being supplied to the gas supply chamber. You. Therefore,
Even if a failure occurs in the supply device or the like, the interior of the chamber is contaminated by a contaminant such as an organic substance volatilized from an adhesive for fixing an optical element such as a lens, for example, until a certain time elapses. Until the exposure processing cannot be continued), the exposure processing can be continued. Further, it is possible to prevent the optical system of the exposure apparatus from being contaminated.

3. The device manufacturing method of the present invention includes a step of transferring an image of a pattern of a mask (R) to a substrate (W) using the above-described exposure apparatus. According to the device manufacturing method of the present invention, the exposure process is performed using the exposure apparatus that sufficiently suppresses the reduction in the illuminance of the exposure beam and the occurrence of illuminance unevenness, so that a high-quality device is manufactured with high throughput. be able to.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An exposure apparatus according to an embodiment of the present invention will be described below with reference to the drawings. This exposure apparatus is a step-and-scan type reduction projection exposure apparatus (stepper).

First, reference is made to FIG. This exposure apparatus
It is installed in a clean room on a floor F on a floor where a semiconductor manufacturing plant is located. In the exposure apparatus of this embodiment, the light source 1
1 is installed on the same floor F as the exposure main body 12,
In order to reduce the footprint of the exposure main body 12, the light source 11 may be installed in a so-called machine room (utility space) below the floor F.

In a clean room on the floor F, a first case, which is a box-shaped light source case, is provided via a plurality of vibration isolating stands 13.
The case 14 is installed, and the illumination light source 1 is provided in the first case 14.
1 (ArF excimer laser light source that oscillates 193 nm excimer laser light in this embodiment) is housed. The first case 14 further includes a beam matching unit (BM) including a movable mirror and the like for positionally matching an optical path with the exposure main body 12.
U) 15 and a light-shielding pipe 16 through which illumination light passes.

Adjacent to the first case 14 for the light source, a box-shaped environment chamber 17 having good airtightness is provided. In the environment chamber 17, a plurality of floors F on the floor F for attenuating vibration from the floor are provided. A platen 19 is installed via a vibration isolator 18 and a platen 1
An exposure main body 12 is provided on 9. Further, the environmental chamber 1 is connected to a pipe 16 protruding from the case 14.
7 have good airtightness to the inside of the subchambers 20A and 20A.
B is installed, and most of the illumination optical system is housed in the sub-chambers 20A and 20B. The sub-chambers include a first sub-chamber 20A, a part of which is arranged inside the environmental chamber 17, and a second sub-chamber 20B, the whole of which is arranged inside the environmental chamber 17. It is composed of Note that the first sub-chamber 20A may be arranged so that the entirety is located inside the environmental chamber 17, or the second sub-chamber 20B may be arranged so that a part thereof is located outside the environmental chamber 17.

The ultraviolet pulse light I having a wavelength of 193 nm as the illumination light emitted from the illumination light source 11 in the first case 14
L reaches the first sub-chamber 20A via the BMU 15 and the pipe 16. In the first sub-chamber 20A, the ultraviolet pulse light IL enters a fly-eye lens 24 via a variable attenuator 21 as an optical attenuator and a beam shaping optical system including lens systems 22 and 23. An aperture stop system 25 of an illumination system for changing illumination conditions in various ways is arranged on the exit surface of the fly-eye lens 24. In addition,
Instead of using the fly-eye lens 24 as an optical integrator (homogenizer), a rod integrator (internal reflection type integrator), a diffractive optical element, or the like can be used.

The ultraviolet pulse light IL emitted from the fly-eye lens 24 and having passed through a predetermined aperture stop in the aperture stop system 25 is reflected by a reflection mirror 26 and a condenser lens system 27.
Fixed illumination field stop (fixed blind) 29 having a slit-shaped opening in reticle blind mechanism 28
Incident on. Further, in the reticle blind mechanism 28, a movable blind 30 for varying the width of the illumination visual field in the scanning direction is provided separately from the fixed blind 29.

The ultraviolet pulse light IL shaped like a slit by the fixed blind 29 of the reticle blind mechanism 28
Reaches the inside of the second sub-chamber 20B. Next, the ultraviolet pulse light IL is applied to the imaging lens system 31, the reflection mirror 32,
Then, a slit-shaped illumination area on the circuit pattern area of the reticle R is irradiated with a uniform intensity distribution via the main condenser lens system 33.

In this embodiment, the first sub-chamber 20
A second case (double cover) 34 is provided so as to cover a portion arranged outside the environmental chamber 17 of A. A first half of the illumination optical system from the light source case 14 to the environmental chamber 17 is provided. , The first sub-chamber 20 </ b> A and the second case 34 are protected by double partition walls.

Under the ultraviolet pulse light IL, the image of the circuit pattern in the illumination area of the reticle R is transferred to the slit-shaped exposure area of the resist layer on the wafer W via the projection optical system PL. The exposure region is located on one of the plurality of shot regions on the wafer W.
The projection optical system PL of this embodiment is a dioptric system (refraction system), but the projection optical system PL is a catadioptric system (reflection / refraction system) or a reflection system, and the ultraviolet pulse light in the projection optical system PL is used. The transmittance of the IL may be increased. In the description below, the Z axis is taken in parallel with the optical axis AX of the projection optical system PL, the X axis is taken in a plane perpendicular to the Z axis, parallel to the plane of FIG. 1, and the Y axis is taken perpendicular to the plane of FIG. I do.

The reticle R is held by suction on a reticle stage 35. The reticle stage 35 is mounted on a reticle base 36 via an air bearing (not shown) so as to be movable in the X direction (scanning direction), and is driven by a linear motor (not shown). . Further, the reticle base 35 can be finely moved in the Y direction and the rotation direction. The two-dimensional position and rotation angle of the reticle stage 35 (reticle R) are controlled by a drive control unit (not shown) provided with a laser interferometer.

On the other hand, the wafer W is held by suction on a wafer holder 37, and the wafer holder 37 is fixedly or detachably mounted on a wafer stage 38. The wafer stage 38 is slidably mounted in the X and Y directions via an air bearing on the surface plate 19, and is driven by a linear motor (not shown) to move the wafer W in the X direction. Fast scanning and stepping in the X and Y directions are performed. Also, the wafer stage 38
The focus position (Z
Direction) and the tilt angle, so that the surface of the wafer W can be adjusted to the image plane of the projection optical system PL. The two-dimensional position and rotation angle of the wafer stage 38 (wafer W) are also controlled by a drive control unit (not shown) equipped with a laser interferometer.

At the time of scanning exposure, the reticle R is applied to the illumination area of the ultraviolet pulse light IL via the reticle stage 35.
Is scanned in the + X direction (or -X direction) at the speed Vr, and the wafer W moves in the -X direction (or + X direction) with respect to the exposure region via the wafer stage 38 at the speed β · V.
The scanning is performed at r (β is a projection magnification from the reticle R to the wafer W).

Hereinafter, a purge system of the exposure apparatus will be described. This exposure apparatus includes a nitrogen purge system using nitrogen gas and a dry air purge system using clean dry air.

First, the nitrogen purge system will be described. In FIG. 1, a first case 14 for a light source, a first sub-chamber 20A, a second sub-chamber 20B, and a projection optical system PL
Are connected to branch pipes 39A, 39B, 39C, 39D of a pipe 39 for supplying a purge gas (nitrogen gas), and branch pipes 40A, 40B, 40C, 40D of a pipe 40 for discharging a purge gas. Is connected.

The end of the pipe 39 on the purge gas supply side is the first
The other end of the factory piping 42 is connected to one end of the factory piping 42 via the line filter unit 41.
It is connected to a nitrogen supply device 43 equipped with a cylinder filled with 9999% or 99.999% purity nitrogen (N ₂ ) gas and a pump or a fan. The line filter unit is one that is arranged in the middle of the gas supply pipe. The end on the purge gas discharge side of the pipe 40 is connected to a recovery device 44 for recovering nitrogen gas. The collection device 44 is not essential, and may be discharged to an external environment outside the clean room or outside the factory. V1 to V10
Is a solenoid valve whose opening and closing can be freely controlled by a purge control device (see FIG. 5).

The solenoid valves V1 to V10 are all opened to supply pipes 42, 39 (39A, 3
9B, 39C, 39D), the first case 14, the first sub-chamber 20A,
The gas in the second sub-chamber 20B and in the lens barrel of the projection optical system PL is discharged through a discharge pipe 40 (40A, 40B, 40C, 4).
0D), the first case 14, the first sub-chamber 20A, the second sub-chamber 20B, and the inside of the lens barrel of the projection optical system PL are replaced with clean nitrogen gas. The supply of the nitrogen gas may be a flow supply in which a constant amount is constantly flowed, or the supply is stopped by closing the solenoid valves V1 to V10 when a sufficient time has elapsed to replace the clean nitrogen. This may be repeatedly performed at regular intervals or as needed.

By selectively operating the solenoid valves V1 to V10, any one of the first case 14, the first sub-chamber 20A, the second sub-chamber 20B, and the lens barrel of the projection optical system PL can be used. Alternatively, the purge gas may be selectively supplied to two or more.

The inside of the first case 14, the first sub-chamber 20A and the second sub-chamber 20B is divided into a plurality of chambers by partition walls or the like, and one or more of the chambers are purged with nitrogen. Is also good. Further, the projection optical system P
One or more of the lens chambers in the lens barrel L or in the lens barrel holding the optical element constituting the illumination optical system may be purged with nitrogen. In addition, a reticle chamber is defined so as to include reticle stage 35, a wafer chamber is defined so as to include wafer stage 38, and a reticle preliminary chamber adjacent to reticle chamber where reticle R is temporarily on standby. Alternatively, a wafer spare chamber in which the wafer W temporarily waits adjacent to the wafer chamber may be defined, and one or more of these may be purged with nitrogen.

Next, the dry air purge system will be described. One end of a pipe 45 for supplying purge gas (clean dry air) is connected to the second case 34.
The other end of 5 is via a second line filter unit 46,
The other end of the factory piping 47 is connected to a dry air supply device 48 including a compressor, a dryer, a purification filter, and the like. V11
Is a solenoid valve whose opening and closing can be freely controlled by a purge control device (see FIG. 5).

By opening the solenoid valve V11 and supplying clean dry air from the dry air supply device 48 via supply pipes 47 and 45, the gas in the second case 34 is replaced with clean dry air. The supply of the clean dry air can be a flow supply in which a constant amount is constantly flowed, or when a sufficient time for replacing the clean dry air has elapsed, the supply is stopped by closing V11 and the supply is stopped for a certain period. It may be performed every time or as needed.

In this embodiment, no special exhaust system is provided for purging the second case 34 with clean dry air. However, the same exhaust system (40, 44, etc.) as the nitrogen gas purge system described above is used. May be provided.

The inside of the second case 34 may be further divided into a plurality of chambers by partition walls or the like, and clean dry air may be independently supplied to each of the chambers. Further, another case similar to the second case 34 may be provided so as to cover a part or all of the first sub-chamber 20B and other parts, and clean dry air may be supplied to the other case. Good. Also, the reticle chamber described above,
When a wafer chamber, a reticle preparatory chamber, or a wafer preparatory chamber is defined, one or more of these may be purged with clean dry air.

As shown in FIG. 2, the interior of the environmental chamber 17 is provided with an air conditioning unit 4 attached to the exposure apparatus.
9 for air conditioning. That is, the air conditioner 49 includes a fan 50 that takes in air in a clean room, a chemical filter, and a HEPA (High Ef).
Purification filter 51 such as a fissiony particle air (FIR) filter and a temperature controller (not shown)
The temperature-controlled and purified air is supplied to the environment chamber 17 through the duct 52 and the like.

More specifically, as shown in FIG. 3, the inside of the environmental chamber 17 is divided into four spaces by partition walls. These four spaces are defined by the projection optical system P
First including reticle stage RS (35) above L
A space SP1, a second space SP2 including a wafer stage WS (38) below the projection optical system PL, a third space SP3 in which a reticle loader system RL for transferring a reticle R is arranged, and a wafer W are transferred. This is a fourth space SP4 in which a wafer loader system WL for performing the operation is arranged.

Air in air-conditioning unit 49 (air inhaled from external clean room and air circulated internally)
Is supplied to each of the first space SP1 to the fourth space SP4 via the upper duct 52A and the like, and the air from each of the first space SP1 to the fourth space SP4 is returned to the air conditioning unit 49 via the lower duct 52B and the like. Is circulated. A plurality of chemical filters 51A and HEPA filters 51B are appropriately arranged on the air flow path, and
Clean air whose temperature has been adjusted is circulated and supplied to the SP4.

In FIG. 2, the nitrogen gas (N ₂ ) for purging and the clean dry air (CDA) correspond to each other via the line filter units 41 and 46.
4, 20A, 20B, PL, and 34. Also,
In this embodiment, the air supplied to the air bearing of the reticle stage 35 or the wafer stage 38 also uses the same clean dry air (CDA) as that for purging.
Purified by a separately provided line filter unit 55 and supplied through a pipe 56. Although not particularly limited, the air filter line filter unit 55 of this embodiment can employ the same as a purge line filter unit (details will be described later). Reference numeral 53 denotes a control signal line connecting the main control device of the exposure apparatus and the control device of the air conditioning unit 49, and reference numeral 54 denotes a power supply line for the air conditioning unit 49.

Next, the most characteristic line filter units 41 and 46 of the present invention will be described. As shown in FIG. 4, the line filter units 41 and 46 house the unit in which the output side of the first filter 57 and the input side of the second filter 58 are connected by the connection pipe 59 in the housing 60. It is configured. Factory pipes 42 and 47 are connected to the input side of the first filter 57, and pipes 39 and 40 are connected to the output side of the second filter 58. The first line filter unit 41 and the second line filter unit 4
6 may be configured independently of each other as shown in FIG. 1 or may be configured to be housed in the same housing as shown in FIG.

The first filter 57 disposed on the upstream side (the supply devices 43 and 48 side) in the supply direction of the purge gas (nitrogen gas or clean dry air) is a filter for mainly removing inorganic substances in the purge gas by physical adsorption. . Here, the physical adsorption refers to an action of adsorbing by attractive force due to interaction of a dipole moment between a substance to be adsorbed and an adsorbed substance, and does not include a removal method such as filtration.
As the first filter 57, a filter (ceramic honeycomb filter) formed by attaching an inorganic material to a ceramic material formed in a honeycomb shape and firing the ceramic material can be used. GIO Co., Ltd. TIOS-DA (trade name) can be employed.

As the inorganic substance in the purge gas to be removed by the first filter 57, ammonia (N
H ₃ ), sulfur dioxide (SO ₂ ), nitric oxide (NO),
Nitrogen dioxide (NO ₂ ), nitrous oxide (N ₂₀ ), H ₂
O (water), silicon (Si) based materials, and the like. When the above-mentioned ceramic honeycomb filter is used as the first filter 57, as the organic substance in the purge gas, DEP (phthalic ester), NMP (n-methylpyrrolidone), n-octanol, ethanol, toluene, oxirene, etc. Can also be removed.

The first filter 57 utilizes physical adsorption. When water is contained in the purge gas, the dipole moment of water is relatively large, so that the dipole moment of water is larger than that of water. Although the ability to remove small substances may be reduced, the purge gas is high-purity nitrogen gas or clean dry air, so that the amount of water in the gas is extremely small, so that sufficient removal performance can be exhibited.

The first filter 57 in the purge gas supply direction
Second filter 58 disposed downstream (exposure apparatus side)
Is used for physical adsorption of mainly organic substances in the purge gas.
Therefore, it is a filter to be removed. In this embodiment, the main
Activated carbon for removing organic substances as inorganic
A filter composed of an impregnating agent to remove substances
Using ruta. As the impregnating agent,
Removal of mechanical system substances (acid or alkali) by neutralization reaction
Counter ion such as ammonia (NH ₃)
Use orthophosphoric acid, sulfonic acid, etc.
Can be. However, such a neutralization reaction
Some amount of water (about 5% or more)
Purge gas should be high purity nitrogen gas or
Because it is dry air, so high removal capacity is expected
I can't. In the present embodiment, the inorganic substance is
Most of them can be removed by the first filter 57,
The second filter 58 is activated for the purpose of removing organic substances.
You may comprise only by the charcoal.

As the second filter 58, activated carbon to which an impregnating agent is added and activated carbon to which no impregnating agent is added may be arranged along the gas flow direction. In this case, the activated carbon to which the impregnating agent is added can remove alkali and acid,
Only activated carbon can remove organic matter. Therefore, it is desirable to arrange a plurality of activated carbons to which an impregnating agent is added and activated carbons to which no impregnating agent is added.

In this embodiment, the first filter 5
7 on the upstream side in the purge gas supply direction, and a second filter 58.
Is also arranged on the downstream side for the following reason. In the case where the external air enters into the purge gas due to the aging of the packing at the pipe connection portion or the like or the failure of the supply devices 43 and 48, but not to the rupture or the rupture of the factory piping 42 or 47, Although the amount of moisture (humidity) in the purge gas increases, the dipole moment of the moisture is large. Therefore, there is a possibility that the substance containing the inorganic substance once adsorbed may be released from the first filter 57. In this case, the second filter This is because it is possible to remove a certain amount of substances including the substances released by 59 (an additive that removes inorganic substances by a neutralization reaction), and it may be possible to supply a purge gas satisfying the specifications. However, the second filter 58 may be arranged on the upstream side in the purge gas supply direction, and the first filter 57 may be arranged on the downstream side.

As described above, the nitrogen gas supplied from the nitrogen supply device 43 via the factory piping 42 is not restricted to the first gas even if impurities enter due to the entry of air from the external environment on the way. First of line filter unit 41
Since mainly inorganic impurities are removed by the filter 57 and mainly organic impurities are removed by the second filter 58, high-purity nitrogen gas having a small amount of impurities is supplied to the first case 14, the first sub-chamber 20A, It can be supplied to the two sub-chambers 20B and the lens barrel of the projection optical system PL.

The dry air supplied from the dry air supply device 48 via the factory piping 47 can be supplied to the second line filter unit even if impurities enter due to the entry of air from the external environment on the way. Similarly, the inorganic and organic impurities are removed by 46, so that clean dry air with less impurities can be supplied into the second case 34, and the first sub-chamber 20A
Even if air enters inside from the outside, the air is clean dry air in the second case 34, so that the exposure process can be continued without so much adverse effect.

When the factory pipes 42 and 47 are broken or the supply devices 43 and 48 are broken, the first line filter unit 41 and the second line filter unit 46 are broken.
Then, when it is no longer possible to supply a purge gas satisfying the specifications, continuing to supply the purge gas containing such an unacceptable impurity not only adversely affects the exposure process, but also causes a problem such as an optical element. This may cause contamination and the like, and in some cases, maintenance of each part of the exposure apparatus is required, which is not preferable.

In this embodiment, the following countermeasures are taken. That is, in FIG. 1, a first dew point meter (detection device) 61 for detecting the amount of water contained in the supplied nitrogen gas is provided downstream of the first line filter unit 41 and the second line filter unit 46 On the downstream side, a second dew point meter (detection device) 62 for detecting the amount of moisture contained in the supplied dry air is provided. The detection values of the first and second dew point meters 61 and 62 are supplied to a purge control device 63 as shown in FIG. The purge control device 63 is a circuit unit including a microcomputer or the like that controls the entire purge system using nitrogen gas and dry air, and includes a storage device (memory) 64.

Further, a first organic substance concentration sensor 66 (such as an oxygen detection sensor) for detecting the concentration of an organic substance contained in the supplied nitrogen gas is provided downstream of the first filter unit 41, and a second line filter is provided. Unit 46
A second organic substance concentration sensor 68 for detecting the concentration of the organic substance contained in the supplied dry air may be provided on the downstream side. Then, the detection values of these organic substance concentration sensors 66 and 67 are supplied to the purge control device 63. And
This detection value is stored in the storage device (memory) 64, similarly to the detection values of the first and second dew point meters 61 and 62.

A predetermined threshold value relating to the amount of water contained in the purge gas based on the specifications is stored in advance in the storage device 64 for each of the nitrogen purge system and the dry air purge system. The detection values of the first dew point meter 61, the second dew point meter 62, the first organic substance concentration sensor 66, and the second organic substance concentration sensor 67 are compared with corresponding threshold values, and the detected value exceeds the threshold value. If so, part or all of the solenoid valves V1 to V11 are switched to the closed state, and the supply of the purge gas is stopped. At this time, the purge control device 63 also notifies the main control device 65 that controls the entire exposure apparatus of the fact. The main controller 65 of the exposure apparatus immediately stops the operation of the exposure apparatus according to the notification, stops the operation at the time when the processing for the lot being processed is completed, or performs a predetermined operation in accordance with the type of the notification. Perform the necessary processing.

Dew point meters 61 and 62 and organic substance concentration sensor 6
As the position where the 6, 67 is provided, as in the present embodiment,
It may be provided not on the downstream side of the first or second line filter unit 41, 46 but on the upstream side. Further, the device for detecting the moisture content is not limited to the dew point meter, and another detecting device may be used.

In the present embodiment, the dew point meters 61 and 62
And a configuration in which two types of sensors whose measurement targets are different from those of the organic substance concentration sensors 66 and 67 are arranged, but a configuration including any one of them may be employed.

Next, the environmental specifications of the exposure apparatus according to the present embodiment are as follows. Note that, in the following description, T.A. O. C means total organic content (total amount of organic components).

(1) The amount of impurities contained in the air in the clean room installed in the factory where the exposure apparatus according to the present embodiment is housed is described in T.S. O. C: <100 μg / m ³ , Si-based substance: <0.1 μg / m ³ , NH ₃ : <10 μg / m ³ , SOx: <1 μg / m ³ , NOx: <1 μg / m ³ , amines: <0 0.1 μg / m ³ .

(2) The amount of impurities contained in the air in the second case 34 is described in T.S. O. C: <5 μg / m ³ , Si-based substance: <0.1 μg / m ³ , NH ₃ : <0.2 μg / m ³ , SOx: <0.2 μg / m ³ , NOx: <0.2 μg / m ³ Amine: <0.1 μg / m ³ , Dew point: <−30 ° C.

(3) First case 14, first sub-chamber 20A, second sub-chamber 20B, and projection optical system PL
Regarding the amount of impurities contained in the nitrogen gas in the lens barrel of T. O. C: <1 μg / m ³ , Si-based substance: <0.1 μg / m ³ , NH ₃ : <0.2 μg / m ³ , SOx: <0.2 μg / m ³ , NOx: <0.2 μg / m ³ Amine: <0.1 μg / m ³ , Dew point: <−70 ° C.

As described above, according to the present embodiment, most of the optical path of the illumination light IL includes the first filter 57 for mainly removing inorganic substances and the second filter 58 for mainly removing organic substances. Since it is filled with the extremely high purity nitrogen gas purified by the first line filter unit 41, the transmittance of the illumination light IL is extremely high. In particular, this is a case where the distance from the nitrogen supply device 43 to the exposure device is long, and there is a high possibility that outside air (air containing a large amount of impurities in the factory) enters while flowing through the factory piping 42. However, the first line filter unit 4
Since it is purified by the method (1), it is possible to continuously realize the environmental specifications as described in (4) above for a long period of time.

The portion of the optical path of the illumination light IL including the portion where the first subchamber 20A is provided is doubled by the second case 34, and the inside of the second case 34 contains mainly an inorganic substance. First filter 57 to be removed
And a second filter 58 for mainly removing organic substances
Is filled with the clean dry air (CDA) that has been purified by the second line filter unit 46 having the following characteristics. Therefore, even if outside air enters the first sub-chamber 20A, the transmission characteristics of the illumination light IL are reduced. It does not have much adverse effect. In particular, the dry air supply device 48
Even if the distance from the exposure apparatus to the exposure apparatus is long and there is a high possibility that outside air (air containing a lot of impurities in the factory) enters while flowing through the factory piping 47, the second line Since purification is performed by the filter unit 46, it is possible to continuously realize the environmental specifications as described in (3) above for a long period of time.

Further, in this embodiment, the first and second dew point meters 61 and 62 and the first and second organic substance concentration sensors 6 are used.
6, 67, the amount of water and the amount of organic substances contained in the supplied purge gas (nitrogen gas, dry air) are measured. If the amount exceeds a predetermined value, the electromagnetic valves V1 to V11 are appropriately closed to purge the purge gas. Since the supply is stopped, the first or second line filter unit 4 may be disabled, for example, a failure may occur in the factory pipes 42, 47 or the supply devices 43, 48.
Exposure processing can be continued for a certain period of time even if the removal cannot be completed anymore in the steps 1 and 46. That is, the first case 14, the first sub-chamber 20
A, Even if a new purge gas is not supplied into the second sub-chamber 20B and the projection optical system PL, those spaces are not immediately contaminated by contaminants naturally generated from, for example, an adhesive or the like. Since it takes a certain amount of time before the treatment becomes contaminated so that the treatment cannot be carried out, if the supply of the purge gas containing a large amount of impurities is immediately stopped, it is not complete but a good one until a certain amount of time elapses. In this state, the exposure processing can be continued.

In the embodiment described above, the first case 14, the first sub-chamber 20A, and the second sub-chamber 20
Although B and the inside of the projection optical system PL are purged with a high-purity nitrogen gas, a gas such as helium, argon, neon, or krypton, or a mixed gas of two or more of them may be used. Although the inside of the second case 34 is purged with clean dry air, the inside of the second case 34 may be purged with nitrogen gas or the like as in the first case 14 or the like. Further, the inside of the environment chamber 17 may be purged with clean dry air or nitrogen gas in the same manner as in the second case 34 or the first case 14 or the like.
Also in these cases, the purge gas sent from the purge gas supply device via the factory piping includes a first filter 57 for mainly removing inorganic substances and a second filter 58 for mainly removing organic substances in series. By using the connected line filter unit, purification is performed at a position immediately before being supplied to the exposure apparatus.

Further, in addition to the dew point meter and the organic substance concentration sensor, a sensor for detecting the concentration of the inorganic substance contained in the purge gas may be provided.

The embodiments described above are described for facilitating the understanding of the present invention, but are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, in the above-described embodiment, an exposure apparatus employing a device that emits ArF excimer laser light (wavelength: 193 nm) as a light source has been described. However, there is no particular limitation, and g-line (436 nm), i-line Line (36
5 nm), KrF excimer laser (248 nm), F
_Two lasers (157 nm) or the like can be employed.

A single-wavelength laser in the infrared or visible range oscillated from a DFB semiconductor laser or a fiber laser as exposure illumination light is amplified by, for example, a fiber amplifier doped with erbium (or both erbium and yttrium). Alternatively, a harmonic converted to ultraviolet light using a nonlinear optical crystal may be used.

For example, the oscillation wavelength of a single wavelength laser is set to 1.
When the wavelength is in the range of 51 to 1.59 μm, the generated wavelength is 18
An eighth harmonic having a wavelength in the range of 9 to 199 nm or a tenth harmonic having a generation wavelength in the range of 151 to 159 nm is output. In particular, the oscillation wavelength is 1.544 to 1.553 μm.
m, 8 in the range of 193 to 194 nm.
A harmonic wave, that is, ultraviolet light having substantially the same wavelength as the ArF excimer laser is obtained, and the oscillation wavelength is set to 1.57 to 1.58 μm.
m, 1 in the range of 157 to 158 nm.
0 harmonic, i.e., ultraviolet light having almost the same wavelength as the F ₂ laser is obtained.

The oscillation wavelength is set to 1.03 to 1.12 μm.
, A 7th harmonic whose output wavelength is in the range of 147 to 160 nm is output.
Assuming that the wavelength is in the range of 099 to 1.106 μm, the generated harmonic is the seventh harmonic in the range of 157 to 158 μm, that is, F _2.
Ultraviolet light having substantially the same wavelength as the laser is obtained. In addition,
As a single-wavelength oscillation laser, ytterbium-doped
A fiber laser is used.

In the above description, the step-and-scan type reduction projection type exposure apparatus (scanning
Stepper) has been described, but the entire surface of the reticle pattern is irradiated with exposure light in a state where the reticle and the wafer are stationary, and one section area (shot area) on the wafer where the reticle pattern is to be transferred. The present invention can be applied to a reduction projection type exposure apparatus (stepper) of a step-up / repeat type for static exposure. Further, the present invention can be applied to a step-and-stitch type reduction projection exposure apparatus, a mirror projection aligner, and the like.

Further, not only an exposure apparatus used for manufacturing a semiconductor element and a liquid crystal display element, but also an exposure apparatus used for manufacturing a plasma display, a thin-film magnetic head, an imaging device (such as a CCD), a micromachine, a DNA chip, and the like. The present invention is also applicable to an exposure apparatus that transfers a circuit pattern onto a glass substrate, a silicon wafer, or the like in order to manufacture a reticle or a mask. That is, the present invention is applicable irrespective of the exposure method and application of the exposure apparatus.

The above-described exposure apparatus (FIG. 1) according to the embodiment of the present invention includes a light source 11, illumination optical systems 21 to 33 including various optical elements or optical devices, and a reticle movement including a reticle stage 35. System, wafer stage 38
The elements shown in FIG. 1 such as a wafer moving system and a projection optical system PL including the first case 14, the second case 34,
Factory pipes appropriately housed in the sub-chamber 20A, the second sub-chamber 20B, and the environment chamber 17 and connected to the supply devices 43, 48 via pipes 39, 40 and filter units 41, 46 in these cases and the like. It is manufactured by connecting to the terminals 42 and 47 to realize a predetermined environmental specification, and then assembling them by connecting them electrically, mechanically or optically, and then performing comprehensive adjustment (electrical adjustment, operation check, etc.). You.
It is desirable that the manufacture of the exposure apparatus be performed in a clean room in which the temperature, cleanliness, and the like are controlled.

To produce devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.) using the exposure apparatus according to the embodiment of the present invention, first, in the design step, (For example, circuit design of a semiconductor device) and a pattern design for realizing the function. Subsequently, in a mask manufacturing step, a mask on which the designed circuit pattern is formed is manufactured. On the other hand, in a wafer manufacturing step, a wafer is manufactured using a material such as silicon.

Next, in the wafer process step,
Using the mask and wafer prepared in the above steps, an actual circuit or the like is formed on the wafer by lithography technology. Next, in an assembling step, chips are formed using the wafer processed in the wafer process step. This assembling step includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). Finally, in an inspection step, inspections such as an operation confirmation test and a durability test of the device manufactured in the assembly step are performed. After these steps, the device is completed and shipped.

[0081]

According to the present invention, as described in detail above, a gas from which impurities are sufficiently removed can be supplied to the optical path of the exposure beam, so that the illuminance of the illumination light decreases or the illuminance distribution becomes uneven. This has the effect of preventing the situation from occurring. Further, in the event that a gas that satisfies the specification regarding the content of gaseous impurities cannot be supplied, the supply of the gas is immediately stopped, so that the exposure process can be continued for a certain period of time. This has the effect that contamination of the exposure apparatus can be prevented. Therefore, a decrease in throughput and a decrease in exposure accuracy can be suppressed.

[Brief description of the drawings]

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

FIG. 2 is a diagram schematically illustrating an air conditioning system and a purge system of the exposure apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram for explaining air conditioning in an environment chamber of the exposure apparatus according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a schematic configuration of a line filter unit employed in the exposure apparatus according to the embodiment of the present invention.

FIG. 5 is a block diagram illustrating a configuration of a purge control system of the exposure apparatus according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Illumination light source 12 ... Exposure main body part 14 ... 1st case 17 ... Environmental chamber 20A ... 1st subchamber 20B ... 2nd subchamber 21-33 ... Illumination optical system 34 ... 2nd case 39, 39A-39D, 40, 40A-40D, 45 ...
Piping 41: First line filter unit 42, 47 ... Factory piping 43 ... Nitrogen supply unit 46 ... Second line filter unit 48 ... Dry air supply unit 49 ... Air conditioning unit 57 ... First filter 58 ... Second filter 61 ... First dew point Total 62 62nd dew point meter 63 Purge control device V1-V11 Solenoid valve IL Illumination light PL Projection optical system R Reticle W Wafer

Claims (10)

[Claims] 1. An exposure apparatus for exposing a substrate with an exposure beam, wherein the exposure apparatus is defined to include at least one of a space including at least a part of an optical path of the exposure beam or a space disposed adjacent to the space. A gas supply chamber, a supply device for supplying a gas through which the exposure beam passes, provided in a gas supply path from the supply device to the gas supply chamber, and at least an inorganic substance contained in the gas. An exposure apparatus comprising: a first filter for removing; and a second filter provided in a supply path of the gas and for removing at least an organic substance contained in the gas. 2. The exposure apparatus according to claim 1, wherein the first filter is a ceramic honeycomb filter to which an inorganic material is attached, and the second filter is an activated carbon filter. 3. The filter according to claim 1, wherein the first filter and the second filter are arranged such that the first filter is located upstream and the second filter is located downstream with respect to the flow direction of the gas. 3. The exposure apparatus according to 2. 4. A detection device for detecting the concentration of at least one of an organic substance and moisture contained in a gas flowing through the supply path, and when a detection result by the detection device exceeds a predetermined value. 4. The exposure apparatus according to claim 1, further comprising: a control device configured to stop supply of gas from the supply device to the gas supply chamber. 5. 5. The inorganic material removed by the first filter includes at least one of ammonia, sulfur dioxide, nitrogen monoxide, nitrogen dioxide, and nitrous oxide. The exposure apparatus according to any one of claims 1 to 4. 6. The high pressure gas supplied to the gas supply chamber.
The first filter and the second filter are pure nitrogen gas.
Amount of impurities contained in the nitrogen gas that has passed through the filter
However, the total amount of organic components is 1 μg / m³Below, Silico
0.1 μg / m³Below, ammonia
0.2 μg / m³Below, about sulfur oxide
Is 0.2 μg / m³Hereinafter, for nitrogen oxides, 0.2
μg / m ³Hereinafter, the dew point of moisture is -70 ° C or less.
The method according to any one of claims 1 to 5, wherein
Exposure equipment. 7. The method according to claim 7, wherein the gas supplied to the gas supply chamber is dry air, and the amount of impurities contained in the dry air that has passed through the first filter and the second filter is 5 μg / organic component total amount. m ³ or less, 0.1 μg / m ³ or less for silicon-based material, 0.2 μg / m ³ or less for ammonia, and 0.2 μg for sulfur oxide.
g / m ³ or less, and 0.2 μg / m ³ for nitrogen oxides
The exposure apparatus according to any one of claims 1 to 5, wherein the moisture has a dew point of -30C or less. 8. An exposure apparatus for exposing a substrate with an exposure beam, comprising: a gas supply defined to include at least one of an optical path of at least a part of the exposure beam or a space disposed adjacent to the optical path. A supply device for supplying a gas through which the exposure beam passes, provided in a gas supply path from the supply device to the gas supply chamber, and an organic substance or moisture contained in the gas in the supply path. A detection device for detecting at least one concentration, and a control device for stopping supply of the gas by the supply device to the gas supply chamber when a detection result by the detection device exceeds a predetermined value. An exposure apparatus comprising: 9. A filter provided in a gas supply path from the supply device to the gas supply chamber and removing a light-absorbing substance contained in the gas and absorbing the exposure beam. 9. The exposure apparatus according to 8. 10. A device manufacturing method comprising a step of transferring an image of a mask pattern onto a substrate using the exposure apparatus according to claim 1. Description: