JP2004170802A - Reticle drying apparatus, exposure apparatus, semiconductor device and exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate water molecules adsorbed to the reticle substrate and the pellicle of a reticle. <P>SOLUTION: A reticle drying apparatus 3 is disposed in an exposure apparatus. Before the reticle 7 is mounted on a reticle stage in an exposure unit, the reticle 7 is held by using a holding part 35 while avoiding contact with a drying source 32 in the reticle drying apparatus 3, the chamber 31 is evacuated by an evacuating mechanism 33, and the reticle 7 is heated and dried by using a drying source 32 while purging the chamber 31 with a purging mechanism 34. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor manufacturing apparatus, and more particularly to a reticle drying apparatus, an exposure apparatus, and an exposure method for manufacturing a semiconductor device.
[0002]
[Prior art]
Conventionally, a pellicle has been mounted to prevent foreign matter from adhering to a pattern forming surface of a reticle (photomask) (for example, see Patent Document 1). Thus, even if foreign matter adheres to the surface of the pellicle, the image of the foreign matter is defocused and is not formed on the wafer.
[0003]
[Patent Document 1]
JP 2000-305253 A (page 2)
[0004]
[Problems to be solved by the invention]
In recent years, with the miniaturization of patterns in semiconductor processes, the exposure wavelength has been shortened. At present, a main exposure light source used for mass production is a KrF excimer laser having a wavelength of 248 nm, followed by an ArF excimer laser having a wavelength of 193 nm, which is a light source in a vacuum ultraviolet region. Further, research using an F ₂ excimer laser having a wavelength of 157 nm as a light source has been conducted.
[0005]
However, rays of F ₂ excimer laser, is absorbed by the oxygen molecules and water molecules. For example, when the oxygen molecule concentration is 10 ppm, the transmittance decreases to 90% at an optical path length of about 0.7 m. For example, when the water molecule concentration is 10 ppm, the transmittance is reduced to 90% at an optical path length of about 1.1 m.
The concentration of oxygen molecules and water vapor can be sufficiently reduced by purging with an inert gas such as nitrogen or helium. However, the adsorbed water molecules cannot be sufficiently removed only by purging.
A large amount of water molecules are adsorbed on a reticle substrate made of synthetic quartz or a pellicle made of an organic polymer, so that exposure light is absorbed by the reticle substrate and the pellicle. Therefore, when pattern exposure is performed using a reticle, there is a problem that energy of exposure light sufficient for pattern formation on a wafer cannot be obtained.
Further, when the adsorbed water attached to the pellicle absorbs the exposure light, a chemical reaction occurs on the surface and inside of the pellicle, and there is a possibility that the durability of the pellicle to the exposure light is reduced.
[0006]
The present invention has been made to solve the above-mentioned conventional problems, and has as its object to remove water molecules adsorbed on a reticle substrate and a pellicle.
[0007]
[Means for solving the problem]
A reticle drying apparatus according to the present invention includes a chamber for drying a reticle.
[0008]
The reticle drying apparatus according to the present invention is characterized in that the reticle is dried under reduced pressure.
[0009]
The reticle drying apparatus according to the present invention is further characterized by further comprising a holding section for holding the reticle in the chamber so as not to contact a drying source.
[0010]
The reticle drying apparatus according to the present invention further comprises a purge mechanism for purging the inside of the chamber with an inert gas.
[0011]
An exposure apparatus according to the present invention includes the above reticle drying apparatus.
[0012]
A semiconductor device according to the present invention is manufactured using the above exposure apparatus.
[0013]
Exposure method according to the present invention, a drying step of drying the reticle,
An exposure step of exposing a pattern on a substrate using the dried reticle,
It is characterized by including.
[0014]
The exposure method according to the present invention is characterized in that exposure is performed using a vacuum ultraviolet ray having a wavelength of 160 nm or less as a light source.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts have the same reference characters allotted, and description thereof may be simplified or omitted.
[0016]
FIG. 1 is a schematic diagram for explaining an exposure apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining a reticle drying apparatus in the exposure apparatus shown in FIG. FIG. 3 is a view for explaining an example of a reticle loader in the exposure apparatus shown in FIG. More specifically, FIG. 3A is a schematic view showing a reticle loader in the exposure apparatus, and FIG. 3B is a cross-sectional view taken along line AA ′ of FIG. 3A, showing a reticle loader arm. It is. FIG. 4 is a view for explaining an example in which a reticle is mounted on an arm of a reticle loader in the exposure apparatus shown in FIG. 4A is a top view showing a state where the reticle is held by the arm of the reticle loader, and FIG. 4B is a cross-sectional view taken along the line BB ′ of FIG. 4A.
[0017]
As shown in FIG. 1, the exposure apparatus 1 includes a reticle storage 2 in which a plurality of reticles 7 are stored, a reticle drying apparatus 3 for removing water molecules adsorbed on a reticle substrate of the reticle 7 and a pellicle surface, and a reticle. A reticle loader 4 for transporting the reticle 7; and an exposure unit 10 for exposing the pattern of the reticle 7 on the wafer.
[0018]
In the exposure unit 10, reference numeral 5 is F ₂ excimer laser as an exposure light source (beam line), 6 illumination system 7 is a reticle mounted on a reticle stage (not shown), 8 the projection system, 9 on the upper surface 2 shows a wafer stage on which a wafer (not shown) is placed.
[0019]
The reticle 7 includes a reticle substrate 71 having a pattern forming surface, a pellicle frame 72 made of, for example, aluminum, mounted on the reticle substrate 71, and a pellicle 73 attached to an end surface of the pellicle frame 72 with an adhesive. It is configured. The pellicle frame 72 and the pellicle 73 prevent foreign matter from adhering to the pattern formation surface of the reticle substrate 71. The pellicle 73 is, for example, a transparent organic polymer film having a thickness of 600 nm to 1500 nm. The pattern formation surface of the reticle substrate 71 is separated from the pellicle 73 by, for example, about 6 mm. As shown in FIG. 2, a hole 72a that can be opened and closed is formed in the pellicle frame 72. The hole 72a is normally closed, and is opened when drying under reduced pressure in the reticle drying device 3.
[0020]
As shown in FIG. 2, the reticle drying device 3 includes a chamber 31 as a processing chamber, a drying source 32 provided in the chamber 31 such as a heater and an infrared lamp, and an exhaust mechanism 33 for reducing the pressure in the chamber 31. A purge mechanism 34 for introducing dry air or an inert gas such as nitrogen or helium into the chamber 31 as a purge gas, and a holding unit 35 for holding the reticle 7 in the chamber 31 without contact with the drying source 32. .
[0021]
The exhaust mechanism 33 includes an opening / closing valve and a pump (dry pump, turbo molecular pump). In addition to the introduction of the purge gas, the purge mechanism 34 supplies an inert gas for venting.
Note that, as the drying source 32 in the reticle drying device 3, an oscillator that oscillates electromagnetic waves or ultrasonic waves such as microwaves may be used instead of a heater or an infrared lamp. Also in this case, the water molecules adsorbed on the surfaces of the reticle substrate 71 and the pellicle 73 can be removed.
Further, the holding unit 35 is not limited to the one having the arm shape sandwiching the side surface of the reticle substrate 71 as shown in FIG. 2, but holds the peripheral portion of the reticle substrate 71 (around the pattern forming surface) from below. You may. Also in this case, the reticle 7 is held in the chamber 31 so as not to contact the drying source 32.
[0022]
As shown in FIGS. 1 and 3A, the reticle loader 4 is a transfer device that transfers the reticle 7 between the reticle storage 2, the reticle drying device 3, and the exposure unit 10 (reticle stage). The reticle loader 4 has an arm 41, and as shown in FIG. 3B, when the reticle 7 is delivered, the arm 41 expands and contracts.
Further, as shown in FIG. 4, the reticle substrate 71 of the reticle 7 may be held by two arms 41 from below.
Although not shown, the reticle 7 is held on the arm 41 by vacuum suction.
[0023]
Next, the operation of the exposure apparatus will be described.
[0024]
First, a desired reticle 7 is taken out of the reticle storage 2 by the arm 41 of the reticle loader 4, and the taken out reticle 7 is conveyed to the reticle drying device 3 by the reticle loader 4. The reticle with pellicle 7 transported to the reticle drying device 3 is held in the chamber 31 by the holding unit 35 so as not to come into contact with the drying source 32.
[0025]
Next, in the reticle drying device 3, water molecules adsorbed on the surfaces of the reticle substrate 71 and the pellicle 73 of the reticle 7 are removed. In detail, the inside of the chamber 31 is evacuated using the exhaust mechanism 33, or the inside of the chamber 31 is purged with an inert gas by the purge mechanism 34 after the pressure is reduced and the surfaces of the reticle substrate 71 and the pellicle 73 are dried with Heat and dry using No. 32. After the heating and drying, the inside of the chamber 31 is vented to the atmospheric pressure.
[0026]
After the reticle substrate 71 and the pellicle 73 are dried, the reticle 7 is conveyed from the reticle drying device 3 to the exposure unit 10 by the reticle loader 4, and is mounted on a reticle stage (not shown). Then, in the exposure unit 10, a pattern on the wafer on the wafer stage 9 is exposed using the reticle 7 with a pellicle. At this time, even with a F ₂ excimer laser as an exposure light source 5, the absorption of light by the reticle substrate 71 and pellicle 73 does not occur.
[0027]
After the exposure, the reticle 7 is returned to a predetermined position in the reticle storage 2 by the reticle loader 4.
[0028]
As described above, in the present embodiment, the reticle drying apparatus 3 is provided in the exposure apparatus 1, and before the reticle 7 taken out from the reticle storage 2 is mounted on the reticle stage in the exposure unit 10, the reticle drying apparatus 3 is used. In 3, the reticle 7 was dried to remove water molecules adsorbed on the surfaces of the reticle substrate 71 and the pellicle 73. Therefore, the transmittance at a wavelength of 160nm or less in the vacuum ultraviolet region light used for exposure (F ₂ excimer laser beam) is sufficiently obtained, the energy of sufficient exposure light obtained in the pattern formation on the wafer. Further, the photodecomposition reaction between the pellicle 73 and water molecules adsorbed on the surface thereof can be prevented, and the deterioration of the pellicle 73 can be prevented. Further, by manufacturing a semiconductor device using this exposure apparatus, a fine pattern can be formed.
[0029]
In the present embodiment, the reticle drying device 3 is provided inside the exposure device 1, but the reticle drying device 3 may be provided outside the exposure device 1.
[0030]
If the reticle storage 2 is in an environment where the reticle storage 2 is sufficiently dried, the reticle 7 may be dried in the reticle drying device 3 before the reticle 7 is stored in the reticle storage 2, that is, after the exposure is completed. In this case, the reticle 7 taken out of the reticle storage 2 may be directly conveyed to the reticle stage of the exposure unit 10 without passing through the reticle drying device 3.
[0031]
Although the reticle is dried under reduced pressure in the reticle drying device 3, it may be dried at atmospheric pressure.
[0032]
Further, in the present embodiment uses the F ₂ excimer laser as the exposure light source 5, is also applicable to the present invention when using a light source such as a KrF excimer laser or ArF excimer laser.
[0033]
Further, in the present embodiment, reticle 7 having pellicle frame 71 and pellicle 73 has been described, but a reticle including reticle substrate 71 having no reticle may be used.
[0034]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the water molecule adsorbed on the reticle substrate and pellicle of a reticle can be removed.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining an exposure apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic diagram for explaining a reticle drying apparatus in the exposure apparatus shown in FIG.
FIG. 3 is a diagram for explaining an example of a reticle loader in the exposure apparatus shown in FIG.
4 is a diagram for explaining an example in which a reticle is mounted on an arm of a reticle loader in the exposure apparatus shown in FIG.
[Explanation of symbols]
1 exposure apparatus 2 reticle stocker 3 reticle drying device 4 reticle loader 5 light source _{(F 2} excimer laser)
6 Illumination System 7 Reticle 8 Projection System 9 Wafer Stage 10 Exposure Unit 31 Chamber 32 Dry Source 33 Exhaust Mechanism 34 Purge Mechanism 35 Holder 41 Arm 71 Reticle Substrate 72 ぺ Recycle Frame 72 a Hole 73 ぺ Recycle

Claims (8)

A reticle drying device comprising a chamber for drying a reticle. The reticle drying device according to claim 1,
A reticle drying apparatus, wherein the reticle is dried under reduced pressure. The reticle drying device according to claim 1 or 2,
A reticle drying apparatus, further comprising a holding unit for holding the reticle in the chamber so as not to contact a drying source. The reticle drying device according to any one of claims 1 to 3,
A reticle drying apparatus, further comprising a purge mechanism for purging the inside of the chamber with an inert gas. An exposure apparatus comprising the reticle drying apparatus according to claim 1. A semiconductor device manufactured using the exposure apparatus according to claim 5. A drying step of drying the reticle,
An exposure step of exposing a pattern on a substrate using the dried reticle,
An exposure method comprising: The exposure method according to claim 7,
The exposure method, wherein the exposure step uses a vacuum ultraviolet ray having a wavelength of 160 nm or less as a light source.

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