JP2004302107A - Purging system and purging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To rapidly purge the atmosphere in a pellicle space while suppressing damages given to the pellicle or the like. <P>SOLUTION: A photomask has a pattern formed face of a substrate protected by a pellicle stretched over a frame and has at least one aeration hole in each of two opposing faces of the frame. When the atmosphere in the space enclosed by the substrate, the frame and the pellicle of the photomask is to be displaced, the photomask is housed in a chassis with the above two opposing faces vertically opposing to each other, and a purging gas lighter than the atmosphere in the space of the photomask is supplied from upside to the chassis. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a purge device and a purge method. More specifically, the present invention relates to a purge device and a purge mechanism for purging a space in a photomask protected by a pellicle.
[0002]
[Prior art]
In a lithography process in semiconductor manufacturing, a pattern formed on a reticle serving as a mask master is irradiated with light, and light transmitted through the photomask is imaged on a wafer to expose a photosensitive agent on the wafer. Thus, a predetermined pattern is transferred to the wafer.
[0003]
If foreign matter directly adheres to the pattern of the reticle used here, the foreign matter is directly transferred together with the pattern, which may lead to a defect of the semiconductor chip. In order to prevent this, a method is generally employed in which a reticle on which a pattern is formed is protected by a thin film called a pellicle.
[0004]
Specifically, the pellicle is stretched over a pellicle frame arranged so as to surround the outside of the pattern forming surface of the reticle, and is arranged at a predetermined interval from the pattern forming surface of the reticle. That is, the portion where the reticle pattern is formed is protected by the pellicle structure composed of the pellicle frame and the pellicle extended from the pellicle frame so that foreign matter does not adhere.
[0005]
Further, the pellicle frame is provided with a ventilation hole to prevent deformation of the pellicle due to a pressure change or the like in a space closed by the reticle and the pellicle structure (hereinafter, referred to as a pellicle space). . In addition, a filter that captures foreign matter is provided in the ventilation hole to prevent foreign matter from entering the pellicle space.
[0006]
By the way, with the recent miniaturization of semiconductor integrated circuits, the wavelength of exposure light has been shortened in the lithography process, and accordingly, the transparency of the atmosphere through which the exposure light passes has become a problem. Specifically, for example, as next-generation exposure light, F ₂ Exposure technology using excimer laser light is being developed. ₂ When excimer laser light is used, light absorption by oxygen or moisture cannot be ignored. For this reason, a technique is employed in which the inside of the exposure apparatus is purged with an inert gas such as nitrogen which absorbs little laser light.
[0007]
In the exposure, as described above, when used as a mask in which the reticle pattern formation surface is protected by the pellicle structure, the exposure light may be absorbed by the gas in the pellicle space. For this reason, a method is employed in which the pellicle space is filled with an inert gas through a vent hole provided in the pellicle frame, and thereby the gas in the pellicle space is replaced with a high-purity inert gas and purged. (For example, refer to Patent Document 1).
[0008]
[Patent Document 1]
JP 2001-133961 A
[0009]
[Problems to be solved by the invention]
When replacing the gas in the pellicle space, a process that relies on natural replacement from the vent hole requires a great deal of time. The filter is provided in the vent hole of the pellicle frame as described above. This filter is necessary in order to prevent particles from adhering to the pattern forming surface of the reticle. However, this filter basically makes the pellicle space a closed space, so that the replacement of gas in the pellicle space is more difficult. For this reason, the gas replacement requires a longer time, which leads to a decrease in throughput.
[0010]
Further, it is conceivable that the gas in the pellicle space is replaced in a short time by evacuation. However, a process involving a large change in atmospheric pressure between the inside and outside of the pellicle space is not preferable because it damages the pellicle structure such as deformation of the pellicle.
[0011]
Accordingly, the present invention proposes an improved purging apparatus and a purging method for solving the above-mentioned problems and for suppressing the damage to the pellicle structure and quickly replacing and purging the atmosphere in the pellicle space. Things.
[0012]
[Means for Solving the Problems]
Therefore, in the purging apparatus according to the present invention, the pattern forming surface of the substrate is protected by the pellicle stretched over the frame, and at least two ventilation holes are provided on two opposing surfaces of the frame. A purge device for replacing an atmosphere in a space closed by the substrate, the frame, and the pellicle through the ventilation hole,
A housing for housing the photomask,
A holding unit that holds the photomask in such a manner that one of the two opposing surfaces of the photomask is on the lower side and the other is on the upper side;
Inside the housing, an upper supply port for supplying a purge gas from above,
A lower exhaust port for exhausting the atmosphere in the housing from below,
In the housing, from below, a lower supply port for supplying a heavy purge gas heavier than the purge gas from above,
An upper exhaust port for exhausting the atmosphere in the housing from above,
It is provided with.
[0013]
Further, in the purging method according to the present invention, the pattern forming surface of the substrate may be protected by a pellicle stretched over a frame, and the opposing two surfaces of the frame may include at least one ventilation hole. A purge method for replacing an atmosphere in a space enclosed by the substrate, the frame, and the pellicle,
A photomask accommodating step of disposing the opposing two surfaces in a housing for accommodating the photomask so as to face up and down;
A purge gas supply step of supplying a purge gas lighter than the atmosphere in the space from above to the housing;
A heavy purge gas supply step of supplying a heavy purge gas that is heavier than the purge gas from above, from below, in the housing;
It is provided with.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In each of the drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will be omitted or simplified. In this embodiment, the atmosphere for purging is N ₂ The case of an atmosphere will be described.
[0015]
Embodiment 1 FIG.
FIG. 1 is a schematic cross-sectional view for explaining a photomask 100 according to Embodiment 1 of the present invention. FIG. 2 is a bottom view of the photomask 100.
[0016]
As shown in FIGS. 1 and 2, the photomask 100 includes a reticle 2, a pellicle 4, and a pellicle frame 6.
A predetermined pattern is formed on the reticle 2. Reticle 2 is 152.4 mm square, thickness d ₂ Is a plate made of synthetic quartz glass with a high transmittance of about 6.35 mm. That is, this plate is 6 inches square and 0.25 inches thick when the size is expressed in inches, and is generally called 6025 blanks. In addition, this high transmittance fluorine-added synthetic quartz glass has a wavelength of 157.6 nm. ₂ It has high transparency to light in a short wavelength region such as an excimer laser.
[0017]
Pellicle 4 is 122 mm × 149 mm square, thickness d ₄ Is a synthetic quartz glass plate of about 0.8 mm. The pellicle 4 is arranged so as to face the pattern forming surface of the reticle 2, and is stretched over the pellicle frame 6.
[0018]
The pellicle frame 6 is arranged so as to surround the outside of the pattern of the reticle 2, as shown in FIG. The pellicle frame 6 is formed of glass having a thermal expansion coefficient substantially equal to that of the 6025 blank. As shown in FIG. 2, the pellicle frame 6 is a hollow rectangular frame, and its size is 122 mm × 149 mm square in outer dimension and the width W of the frame portion. ₆ Is 2.0 mm, height d ₆ Is 3.2 mm. The pellicle frame 6 can hold the pellicle 4 and the reticle 2 at a predetermined interval.
[0019]
In this specification, a pellicle structure in which the pellicle 4 is mounted on the pellicle frame 6 is referred to as a pellicle structure. The pellicle structure has an outer dimension of 122 mm x 149 mm square, and the thickness (height) d of the frame portion is about 4.0 mm in total. In this specification, a pellicle structure attached to the reticle 2 to protect the pattern forming surface is referred to as a photomask, and a space of the photomask closed by the reticle 2 and the pellicle structure is defined as: It is referred to as pellicle space 8.
[0020]
Ventilation holes 10 are provided in the two long sides of the four sides of the pellicle frame 6 that face each other, that is, the frame on the long side of the outer dimension of 149 mm. Further, a filter 12 is provided in the ventilation hole 10. FIG. 1 shows a cross section in a state crossing the long side direction.
[0021]
FIG. 3 is a schematic cross-sectional view illustrating a purge device 200 according to Embodiment 1 of the present invention. FIG. 4 is a schematic cross-sectional view for explaining each member of the purge device 200, and FIG. 4A illustrates a holding unit 210 of the purge device 200. FIG. 4B shows the storage section 220 of the purge device 200. FIG. 5 shows a state when the photomask 100 is taken out from the purge device 200.
[0022]
As shown in FIG. 3, the purging apparatus 200 is configured such that the holding unit 210 and the storage unit 220 are combined to store the photomask 100 in a sealed state.
[0023]
As shown in FIGS. 3 and 4A, the holding unit 210 includes a holding table 22. The holding base 22 has an L-shaped cross section. The holding table 22 vertically holds the photomask 100 in a state where the side of the reticle 2 and one side of the frame 6 are in contact with each other so that the surface of the frame 6 where the ventilation holes 10 are formed faces down. I do. The holding table 22 has fine transmission holes, allows gas to pass therethrough, and also serves as a filter.
[0024]
A supply pipe 24 is provided below the holding table 22. The supply pipe 24 is N ₂ It is connected to a supply source 26 via a valve 28. A lower exhaust pipe 30 is provided alongside the supply pipe 24 provided below the holding table 22. The lower exhaust pipe 30 is provided with a valve 32.
[0025]
As shown in FIGS. 3 and 4B, in the housing section 220, the rear plate 40 and the front plate 42 are arranged to face each other with a width that allows the photomask 100 to be sandwiched therebetween. In addition, a filter section 44 is provided above, sandwiched between the back plate 40 and the front plate 42. One surface below the housing portion 220 is an open surface, and the holding portion 210 fits into this portion as shown in FIG.
[0026]
Further, an opening / closing door 46 is provided on the front plate 42. As shown in FIG. 5, the opening / closing door 46 can be rotated upward by 180 degrees and opened. Further, the opening / closing door 46 is slightly larger than the reticle 2, and the photomask 100 can be pulled out in the horizontal direction when the opening / closing door 46 is open.
[0027]
Referring again to FIG. 4B, a supply pipe 50 is provided above the filter unit 44, and the supply pipe 50 is connected to a He supply source 52 via a valve 54. An upper exhaust pipe 56 is provided alongside the supply pipe 50, and an exhaust valve 58 is provided in the upper exhaust pipe 56.
[0028]
In the purge device 200 configured as described above, as shown in FIG. 3, when the holding unit 210 and the storage unit 220 are combined with each other, ₂ From the supply source 26, N gas is supplied into the purge device 200 through the supply pipe 24. ₂ Gas can be supplied. In addition, He gas can be supplied into the purge device 200 from the He supply source 52 above the purge device 200 via the supply pipe 50. Further, by opening the valves 32 and 58 provided respectively from the lower exhaust pipe 30 and the upper exhaust pipe 56, the gas in the purge device 200 can be exhausted.
[0029]
Here, the He gas is air or N 2 under the same pressure. ₂ Lighter than gas. Therefore, when He gas is supplied into the purge device 200 from the supply pipe 50 disposed above the purge device 200, air that is heavier than He gas, N ₂ The gas naturally moves downward, and is pushed out and discharged from the lower exhaust pipe 30 in which the valve 32 is opened before the He gas.
[0030]
Also, N ₂ The gas is heavier than He gas. Therefore, N is introduced into the purge device 200 from the supply pipe 24 disposed below the purge device 200. ₂ When gas is supplied, N ₂ He gas, which is lighter than gas, naturally moves upward, and N gas flows from the upper exhaust pipe 56 with the valve 58 opened. ₂ It will be pushed out and exhausted before the gas.
[0031]
When the photomask 100 is disposed in the purge device 200, the gas flows in the pellicle space 8 in the same manner. That is, when He gas is supplied into the purge device 200 from above, the He gas enters the pellicle space 8 from the ventilation hole 10 above the photomask 100. At this time, a gas, air or N 2 which is heavier than He gas in the pellicle space 8 ₂ The gas or the like naturally moves downward, and is pushed out and discharged from the lower ventilation hole 10 earlier than the He gas.
[0032]
In the purge device 200, N ₂ When the gas is supplied, N is introduced into the pellicle space 8 through the ventilation hole 10 below the photomask 100. ₂ Gas enters. At this time, N in the pellicle space 8 ₂ Gas, He gas, etc., which is lighter than the gas, naturally moves upward, and N ₂ It will be pushed out and exhausted before the gas.
[0033]
As described above, the purging apparatus 200 secures a flow path in the vertical direction, and uses the natural movement of the gas due to the weight difference of the gas to replace and purge the atmosphere in the pellicle space 8 of the photomask 100. Things. In the present embodiment, finally N ₂ Realize gas atmosphere.
[0034]
FIG. 6 is a flowchart for explaining the purge method according to the first embodiment of the present invention. FIGS. 7 to 11 are schematic cross-sectional views illustrating the state of each step when purging the atmosphere in the pellicle space 8.
Hereinafter, a method of purging the inside of the pellicle space 8 in the photomask 100 using the purge device 200 will be described with reference to FIGS.
[0035]
First, as shown in FIG. 7, the photomask 100 is placed on the holding table 22 of the purge device 200 with the surface on which the ventilation holes 10 are formed facing downward (step S2). Next, the valve 54 is opened, and He gas is supplied from the He supply source 52 into the storage unit 220 via the supply pipe 50 above the storage unit 220 (Step S4). Here, the supply of the He gas sufficiently drives out the residual gas inside the storage section 220 and sufficiently replaces the inside of the storage section 220 with the He gas.
[0036]
Thereafter, as shown in FIG. 8, the photomask 100 is inserted into the accommodating section 220 together with the holding section 210 (Step S6). At this time, the holding unit 210 moves at a moving speed of 0.5 cm / sec while holding the photomask 100. In addition, the supply of He gas to the inside of the accommodating section 220 is in a state of being continued. Therefore, as the holding unit 210 is inserted into the accommodation unit 220, He gas flows into the pellicle space 8 from the upper ventilation hole 10. During this series of operations, the valve 32 connected to the lower exhaust pipe 30 of the holding unit 210 is open. As a result, the atmosphere in the purge device 200 or the pellicle space 8, which is pushed out by the He gas supplied from the supply pipe 50 above the purge device 200, causes the lower vent hole 10, the lower exhaust pipe 30, It is designed to be exhausted from.
[0037]
As shown in FIG. 9, after the holding unit 210 and the housing unit 220 are completely combined and the purge device 200 is closed, a part of the gas exhausted from the lower exhaust pipe 30 is collected, and the gas is collected. Is measured (step S8). After confirming that the oxygen concentration of this gas has become 0.1%, the valve 58 of the upper exhaust pipe 56 on the upper side of the purge device 200 is opened (step S10), so that the gas can be exhausted from above the purge device. I do. Thereafter, the valve 32 connected to the lower exhaust pipe 30 is closed (Step S12), and the exhaust path from the lower side of the purge device is closed.
[0038]
In this state, as shown in FIG. 10, the valve 54 is closed, the supply of He gas is stopped (step S14), and N ₂ The supply of gas is started (step S16). Here, the valve 28 connected to the supply pipe 24 is opened to ₂ The supply of gas from the supply source 26 is started. Here, the valve 58 already connected to the upper exhaust pipe 56 has been opened and is in a state capable of exhausting. N ₂ When the gas supply is started, the He gas already filled in the pellicle space 8 or the purge device 200 becomes N gas. ₂ Prior to the gas, the gas first moves upward and is exhausted from the vent hole 10 and the upper exhaust pipe 56.
[0039]
Thereafter, as shown in FIG. ₂ After the gas is sufficiently filled in the pellicle space 8 and the purge device 200, a part of the gas exhausted from the upper exhaust pipe 56 is collected and ₂ The concentration is measured (Step S18). O ₂ If the concentration is less than 0.03%, the door 46 is opened and the photomask 100 is taken out (step S20). At this time, prior to opening and closing, the atmosphere outside the door is prepared to be a nitrogen atmosphere. Thereafter, the photomask 100 is moved to the transfer section while being kept in a nitrogen atmosphere, and then used for exposure processing.
[0040]
In the exposure apparatus, the photomask 100 is placed on a mask stage, and after the alignment is performed, a transfer process is performed, and a normal process such as a post-exposure bake process and a development process is performed. Then, a resist pattern is formed. Here, the size distribution of the formed resist pattern in the substrate was measured using CD-SEM. The measurement pattern is a line pattern having a design value of 100 nm. The inside of the substrate was measured at 11 mm intervals, and an average value of 98.4 nm and a distribution of 3σ 6.7 nm were obtained. The distribution did not particularly depend on the distribution of transmittance in the illumination or mask portion.
[0041]
As described above, according to the first embodiment, the photomask is arranged in the vertical direction, and the ventilation paths are secured vertically. Then, from the upper supply pipe 50, N ₂ Alternatively, a gas He gas having a specific gravity lighter than air is supplied. Therefore, the atmosphere in the pellicle space 8 naturally moves downward and is exhausted from the lower exhaust pipe 30 before the He gas. In other words, the pellicle space 8 can be replaced with He gas while leaving the flow of natural gas. After that, N, which is a gas heavier than He, ₂ Gas is supplied from the lower supply pipe 24. Therefore, the atmosphere replaced with the He gas in the pellicle space 8 naturally moves upward and becomes N ₂ The gas is exhausted from the upper exhaust pipe 56 before the gas. Here, the pellicle space 8 is filled with N while leaving the flow of natural gas. ₂ It can be replaced by gas. In this way, the pellicle space 8 can be quickly purged without imposing a burden on the pellicle or the like at the time of purging. In the first embodiment, replacement with He gas and N 2 ₂ Gas replacement is performed. Thereby, the replacement with the inert gas is performed twice, so that the concentration of the active gas such as oxygen can be further reduced.
[0042]
In the first embodiment, replacement with He gas from above and N 2 ₂ The case where each replacement with gas is performed once has been described. However, the present invention is not limited to one-time replacement, and the He gas is replaced with N gas until the desired purity is reached in the pellicle space. ₂ The replacement with the gas may be repeatedly performed a plurality of times. The number of such replacements may be determined in consideration of the required purity in the pellicle space, the processing time required for the replacement, and the like.
[0043]
In the first embodiment, the He gas supply source 52 and the N ₂ The gas supply sources 26 are respectively arranged, and He gas is supplied from above, and N gas is supplied from below. ₂ The case where the gas can be supplied has been described. As described above, it is possible to perform two replacements of the replacement with the inert gas supplied from above and the replacement with the inert gas supplied from below, and to remove the active gas such as oxygen gas in the pellicle space 8. This is because the concentration can be made lower. However, the present invention is not limited to such a case. For example, the present invention may include only the upper He gas supply source 52 and the supply pipe 50. Even if these are provided only above the purging device, if an inert gas having a specific gravity lighter than the atmosphere in the pellicle space 8, such as He gas, is supplied, this atmosphere is lowered by natural flow. Therefore, the inside of the pellicle space 8 can be quickly purged to a certain concentration. In this case, the purge gas is not limited to He gas, but may be N ₂ An inert gas lighter than the atmosphere in the pellicle space 8, such as a gas, may be used. Alternatively, an inert gas that is heavier than the atmosphere in the pellicle space 8 may be used, and only the lower gas supply source and the supply pipe 24 may be used. In particular, in this case, the method is suitable as a simple means that can be used for a process for reducing the concentration of an active gas such as oxygen to a target concentration or less, instead of a process for a special atmosphere or the like such as an exposure process.
[0044]
In the first embodiment, the purge device 200 ₂ The case where the gas supply source 26 and the He gas supply source 52 are provided has been described. However, the present invention is not limited to this. For example, the present invention may include only the supply pipes 24 and 50 so as to be connectable to an external supply source. Moreover, the supply pipes 24 and 50 may not be provided, and only the passage opening may be provided above and below.
[0045]
In the first embodiment, the lower exhaust pipe 30 and the upper exhaust pipe 56 of the purge device 200 are provided with only the valves 32 and 58, respectively, and the case where the exhaust means is not particularly provided has been described. This is because, according to the first embodiment, it is possible to easily perform the evacuation by relying on the natural flow of the gas even without having the evacuation means. A sudden change in pressure is not preferable because it causes damage to the pellicle and the like. However, the present invention is not limited to this, and the exhaust pipes 30 and 56 may be provided with exhaust means such as an exhaust pump. However, in this case, the supplied He gas or N ₂ It is necessary to adjust the exhaust amount in consideration of the gas flow rate so as to avoid a sudden pressure change. In the first embodiment, the exhaust device of the purge device 200 in which the exhaust pipes 30 and 56 are provided with the valves 32 and 58 has been described. However, in the present invention, the exhaust means is not limited to the above-described one, and the exhaust means is not provided with the valves 32, 58, or, for example, does not have the exhaust pipes 30, 56, and has an exhaust opening. It may have only one.
[0046]
Further, in the present invention, the shape and material such as the size and thickness of the reticle and the pellicle structure are not limited to those described in the first embodiment. What is necessary is just to be able to replace. Further, in the present invention, the shape and the like of the purging device 200 are not limited to those described in the first embodiment, and the purging apparatus 200 can house a photomask to be purged and perform purging by the same function. If so, other shapes may be used.
[0047]
Embodiment 2 FIG.
FIG. 12 is a schematic sectional view illustrating a purge device according to Embodiment 2 of the present invention.
As shown in FIG. 12, a purge device 300 according to the second embodiment is similar to the purge device 200 according to the first embodiment.
[0048]
However, the purging apparatus 300 includes the supply pipe 60 penetrating the holding table 22 in the holding section 310. The supply pipe 60 is provided at a position directly in contact with the lower ventilation hole 10. The supply pipe 60 is connected to the same N as the supply pipe 24 through a valve 62. ₂ It is connected to a supply source 26. Further, the holding table 22 includes an exhaust pump 64 connected to the lower exhaust pipe 30.
[0049]
Further, the purging apparatus 300 includes a supply pipe 66 that penetrates the filter section 44 in the storage section 320. The supply pipe 66 is provided so as to directly contact the upper ventilation hole 10. The supply pipe 66 is connected to the He supply source 52 via a valve 68. Further, the filter section 44 includes an exhaust pump 70 connected to the upper exhaust pipe 56.
[0050]
With such a structure, when the purge device 300 is used, N is directly supplied from the supply pipes 60 and 66 provided at positions that directly contact the air holes 10 of the photomask 100 into the pellicle space 8 of the photomask. ₂ Gas or He gas can flow in. Thus, as described in the first embodiment, the atmosphere in the pellicle space 8 can be easily replaced by a natural gas flow utilizing the difference in specific gravity. At this time, at the same time, N is also supplied from the supply pipes 24 and 50 to the storage section 320 of the purge device 300. ₂ Gas or He gas is supplied. Therefore, the atmosphere outside the photomask 100 and the atmosphere inside the pellicle space 8 can be individually controlled, and a quick replacement process can be performed under optimal conditions.
[0051]
In addition, in the purge device 300, when supplying He gas from above, the valve 32 provided in the lower exhaust pipe 30 is opened, and exhaust by the exhaust pump 64 is performed simultaneously. In addition, N ₂ When supplying the gas, the valve 58 provided in the upper exhaust pipe 56 is opened, and the exhaust pump 70 performs the exhaust simultaneously. Here, in the exhaust pumps 64 and 70, the exhaust amount is adjusted so as not to give a sudden pressure change in the pellicle space 8.
[0052]
It should be noted that unlike the first embodiment, the purge device 300 uses the supplied He gas or N 2 gas. ₂ The gas does not pass through the filter unit 44 or the holding unit 22 serving as a filter. However, since the filter 12 is provided in the ventilation hole 10, even in this case, it is possible to prevent foreign matter from entering the pellicle space 8 during gas supply.
[0053]
As described above, according to the second embodiment, He gas or N ₂ The gas can flow directly into the photomask from the upper and lower vents 10, respectively. Thus, the atmosphere in the pellicle space 8 can be quickly and easily purged.
[0054]
In the second embodiment, a case has been described in which the lower exhaust pipe 30 and the upper exhaust pipe 56 are provided with the exhaust pumps 64 and 70, respectively, and the exhaust is performed by these. However, the present invention is not limited to this, and may not use the exhaust means as in the first embodiment.
The other parts are the same as those in the first embodiment, and a description thereof will not be repeated.
[0055]
In the present invention, the substrate corresponds to, for example, the reticle of the first or second embodiment, the frame corresponds to, for example, the pellicle frame 6, and the space corresponds to the pellicle space 8. In the present invention, the housing corresponds to, for example, the housing section 220 of the first and second embodiments. In the present invention, the upper supply port corresponds to, for example, the supply pipe 50 of the first and second embodiments, and the lower supply port corresponds to, for example, the supply pipe 24. In the present invention, the upper supply pipe and the lower supply pipe correspond to, for example, the supply pipe 66 and the supply pipe 60 of the second embodiment, respectively. In the present invention, the upper supply source and the lower supply source are, for example, the He supply sources 52 and N of the first and second embodiments, respectively. ₂ The supply source 26 corresponds to the lower exhaust unit and the upper exhaust unit, for example, the exhaust pumps 64 and 70 of the second embodiment, respectively.
[0056]
Further, for example, in the first embodiment, by executing steps S2 and S6, the photomask housing step of the present invention is executed, and by executing step S6, the purge gas supply step is executed. Further, for example, in the first embodiment, by executing step S16, the heavy purge gas supply step of the present invention is executed. In the present invention, the heavy purge gas includes, for example, N 2 in the embodiment. ₂ Gas is applicable. N ₂ By purging with gas, N ₂ The atmosphere required for the exposure atmosphere is secured.
[0057]
【The invention's effect】
As described above, according to the present invention, the purge gas is supplied from above the purge device, the atmosphere in the housing is exhausted from below, and the heavy purge gas that is heavier than the purge gas supplied from above is supplied from below. Then, the atmosphere in the housing can be exhausted from above. In this device, the air holes of the photomask frame are arranged up and down, and a purge gas lighter than the atmosphere in the space of the photomask is supplied from above the purging device, so that the natural gas flow is used. Thus, the atmosphere in the space of the photomask can be easily and quickly extruded. Further, a heavy purge gas heavier than the purge gas can be supplied from below the purge device to extrude the atmosphere in the photomask space. Thus, the atmosphere in the space of the photomask can be purged so as to have a high purity atmosphere. In this case, since a light gas can be supplied from above and a heavy gas can be supplied from below, rapid purging can be performed while suppressing damage to a pellicle or the like by using a natural gas flow.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view for explaining a photomask according to Embodiment 1 of the present invention.
FIG. 2 is a bottom view for explaining the photomask according to the first embodiment of the present invention.
FIG. 3 is a schematic sectional view illustrating a purge device according to Embodiment 1 of the present invention.
FIG. 4 is a schematic cross-sectional view for explaining each member of the purge device according to the first embodiment of the present invention.
FIG. 5 shows a state when the photomask is taken out from the purge device according to the first embodiment of the present invention.
FIG. 6 is a flowchart illustrating a purge method according to the first embodiment of the present invention.
FIG. 7 is a schematic cross-sectional view for explaining a state in each step when purging the inside of the photomask in the first embodiment of the present invention.
FIG. 8 is a schematic cross-sectional view for explaining a state in each step when purging the inside of the photomask in the first embodiment of the present invention.
FIG. 9 is a schematic cross-sectional view for explaining a state in each step when purging the inside of the photomask in the first embodiment of the present invention.
FIG. 10 is a schematic cross-sectional view for explaining a state in each step when purging the inside of the photomask in the first embodiment of the present invention.
FIG. 11 is a schematic cross-sectional view for explaining a state in each step when purging the inside of the photomask in the first embodiment of the present invention.
FIG. 12 is a schematic sectional view illustrating a purge device according to a second embodiment of the present invention.
[Explanation of symbols]
100 Photomask
200, 300 Purge device
210, 310 Holder
220, 320 accommodation section
2 reticle
4 Pellicle
6 pellicle frame
8 pellicle space
10 Vent
12 Filter
22 Holder
24 Supply pipe
26 N ₂ supply source
28 valve
30 exhaust pipe
32 valves
40 back plate
42 front panel
44 Filter section
46 Door
50 supply pipe
52 He source
54 valve
56 exhaust pipe
58 valve
60 supply pipe
62 valve
64 exhaust pump
66 Supply pipe
68 valve
70 Exhaust pump

Claims (16)

The pattern forming surface of the substrate is protected by a pellicle stretched over a frame, and, on two opposing surfaces of the frame, at least one vent hole, of a photomask including at least one, the substrate, the frame, A purge device for replacing an atmosphere in a space closed by the pellicle through the vent hole,
A housing for housing the photomask,
A holding unit that holds the photomask in such a manner that one of the two opposing surfaces of the photomask is on the lower side and the other is on the upper side;
Inside the housing, an upper supply port for supplying a purge gas from above,
A lower exhaust port for exhausting the atmosphere in the housing from below,
In the housing, from below, a lower supply port for supplying a heavy purge gas heavier than the purge gas from above,
An upper exhaust port for exhausting the atmosphere in the housing from above,
A purge device comprising: The purging apparatus according to claim 1, wherein the upper supply port includes an upper supply pipe that can be directly connected to an upper ventilation hole formed in the upper surface of the ventilation holes. The purging device further comprises:
3. The purge device according to claim 1, further comprising an upper supply source connected to the upper supply port and configured to supply a purge gas into the housing. 4. The purging device further comprises:
4. The purge device according to claim 1, further comprising a lower exhaust unit connected to the lower exhaust port for exhausting an atmosphere in the housing. The lower supply port includes a lower supply pipe that can be directly connected to a lower ventilation hole formed in the lower surface of the ventilation holes. A purging apparatus according to claim 1. The purging device further comprises:
The purge device according to claim 1, further comprising a lower supply source connected to the lower supply port and configured to supply the heavy purge gas into the housing space. The purging device further comprises:
The purging apparatus according to claim 1, further comprising an upper exhaust unit connected to the upper exhaust port and exhausting an atmosphere from the inside of the housing. The purging apparatus according to claim 1, wherein the housing includes an opening / closing door for taking the photomask in and out. The purging apparatus according to any one of claims 1 to 8, wherein the purge gas is a helium gas. The purging apparatus according to any one of claims 1 to 9, wherein the heavy purge gas is a nitrogen gas. The pattern forming surface of the substrate is protected by a pellicle stretched over a frame, and, on two opposing surfaces of the frame, at least one vent hole, of a photomask including at least one, the substrate, the frame, A purge method for replacing an atmosphere in a space closed by the pellicle,
A photomask accommodating step of disposing the opposing two surfaces in a housing for accommodating the photomask so as to face up and down;
A purge gas supply step of supplying a purge gas lighter than the atmosphere in the space from above to the housing;
A heavy purge gas supply step of supplying a heavy purge gas that is heavier than the purge gas from above, from below, in the housing;
A purging method comprising: The purge gas supply step may include a supply performed by directly connecting an upper supply pipe for supplying the purge gas to a ventilation hole formed on a surface of the ventilation hole disposed above the ventilation hole. Item 12. The purging method according to Item 11. The heavy purge gas supply step includes a supply that is performed by directly connecting a lower supply pipe for supplying the heavy purge gas to a vent formed on a lower surface of the vent. The purging method according to claim 11 or 12, wherein 14. The purge method according to claim 11, wherein a helium gas is used as the purge gas. The purge method according to any one of claims 11 to 14, wherein a nitrogen gas is used as the heavy purge gas. The purging method according to any one of claims 11 to 15, wherein a process of performing the heavy purge gas supplying step is repeated a plurality of times after performing the purge gas supplying step.

Images