Photocopying – Projection printing and copying cameras – Detailed holder for original
Reexamination Certificate
2002-12-03
2004-10-12
Fuller, Rodney (Department: 2851)
Photocopying
Projection printing and copying cameras
Detailed holder for original
C355S030000, C355S071000, C430S005000
Reexamination Certificate
active
06803996
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device manufacturing-related apparatus, gas purge method, and device manufacturing method and, more particularly, to a device manufacturing-related apparatus (e.g., an exposure apparatus, gas purge apparatus, reticle inspection apparatus, or reticle transfer box) having a space for storing a reticle with a pellicle whose pellicle film is supported by a pellicle frame, a gas purge method of purging the pellicle space within the pellicle frame with inert gas, and a device manufacturing method.
BACKGROUND OF THE INVENTION
A manufacturing process for a semiconductor element such as an LSI or VLSI formed from a micropattern uses a reduction type projection exposure apparatus for printing and forming by reduction projection a circuit pattern drawn on a mask onto a substrate coated with a photosensitive agent. With an increase in the packaging density of semiconductor elements, demands have arisen for further micropatterning. Exposure apparatuses are coping with micropatterning along with the development of a resist process.
Methods of increasing the resolving power of the exposure apparatus include a method of changing the exposure wavelength to a shorter one, and a method of increasing the numerical aperture (NA) of the projection optical system.
As for the exposure wavelength, a KrF excimer laser with an oscillation wavelength of 365-nm i-line to recently 248 nm, and an ArF excimer laser with an oscillation wavelength around 193 nm have been developed. A fluorine (F
2
) excimer laser with an oscillation wavelength around 157 nm is also under development.
An ArF excimer laser with an oscillation wavelength around ultraviolet rays, particularly, 193 nm, and a fluorine (F
2
) excimer laser with an oscillation wavelength around 157 nm are known to have an oxygen (O
2
) absorption band around their wavelength band.
For example, a fluorine excimer laser has been applied to an exposure apparatus because of a short oscillation wavelength of 157 nm. The 157-nm wavelength falls within a wavelength region called a vacuum ultraviolet region. In this wavelength region, light is greatly absorbed by oxygen molecules, and hardly passes through the air. The fluorine excimer laser can only be applied in an environment in which the pressure is decreased to almost vacuum and the oxygen concentration is fully decreased. According to reference “Photochemistry of Small Molecules” (Hideo Okabe, A Wiley-Interscience Publication, 1978, p. 178), the absorption coefficient of oxygen to 157-nm light is about 190 atm
−1
cm
−1
. This means when 157-nm light passes through gas at an oxygen concentration of 1% at one atmospheric pressure, the transmittance per cm is only
T=
exp(−190×1 cm×0.01 atm)=0.150
Oxygen absorbs light to generate ozone (O
3
), and ozone promotes absorption of light, greatly decreasing the transmittance. In addition, various products generated by ozone are deposited on the surface of an optical element, decreasing the efficiency of the optical system.
To prevent this, the oxygen concentration in the optical path is suppressed to low level of several ppm order or less by a purge means using inert gas such as nitrogen in the optical path of the exposure optical system of a projection exposure apparatus using a far ultraviolet laser such as an ArF excimer laser or fluorine (F
2
) excimer laser as a light source.
In such an exposure apparatus using an ArF excimer laser with a wavelength around ultraviolet rays, particularly, 193 nm, or a fluorine (F
2
) excimer laser with a wavelength around 157 nm, an ArF excimer laser beam or fluorine (F
2
) excimer laser beam is readily absorbed by a substance. The optical path must be purged to several ppm order or less. This also applies to moisture, which must be removed to ppm order or less.
For this reason, the interior of the exposure apparatus, particularly, the optical path of ultraviolet rays is purged with inert gas. A load-lock mechanism is arranged at a coupling portion between the inside and outside of the exposure apparatus. When a reticle or wafer is to be externally loaded, the interior of the exposure apparatus is temporarily shielded from outside air. After the load-lock mechanism is purged of oxygen or water with inert gas, the reticle or wafer is loaded into the exposure apparatus.
FIG. 1
is a sectional view schematically showing an example of a semiconductor exposure apparatus having a fluorine (F
2
) excimer laser as a light source and a load-lock mechanism.
In
FIG. 1
, reference numeral
1
denotes a reticle stage for setting a reticle bearing a pattern;
2
, a projection optical system for projecting the pattern on the reticle onto a wafer;
3
, a wafer stage which supports the wafer and is driven in the X, Y, Z, &thgr;, and tilt directions;
4
, an illumination optical system for illuminating the reticle with illumination light;
5
, a guide optical system for guiding light from the light source to the illumination optical system
4
;
6
, a fluorine (F
2
) laser serving as a light source;
7
, a masking blade for shielding exposure light so as not to illuminate the reticle except the pattern region;
8
and
9
, housings which cover the exposure optical path around the reticle stage
1
and wafer stage
3
, respectively;
10
, an He air-conditioner for adjusting the interiors of the projection optical system
2
and illumination optical system
4
to a predetermined He atmosphere;
11
and
12
, N
2
air-conditioners for adjusting the interiors of the housings
8
and
9
to a predetermined N
2
atmosphere;
13
and
14
, reticle load-lock chambers and wafer load-lock chambers used to load a reticle and wafer into the housings
8
and
9
, respectively;
15
and
16
, a reticle hand and wafer hand for transferring the reticle and wafer, respectively;
17
, a reticle alignment portion used to adjust the reticle position;
18
, a reticle stocker for stocking a plurality of reticles in the housing
8
; and
19
, a pre-alignment unit for pre-aligning the wafer.
If necessary, the overall apparatus is stored in an environment chamber (not shown). Air controlled to a predetermined temperature is circulated within the environment chamber to keep the internal temperature of the chamber constant.
FIG. 2
is a schematic sectional view showing another example of the semiconductor exposure apparatus having a fluorine (F
2
) excimer laser as a light source and a load-lock mechanism.
The whole exposure apparatus shown in
FIG. 2
is covered with a housing
20
, and the interior of the housing
20
is purged of O
2
and H
2
O with N
2
gas. Reference numeral
21
denotes an air-conditioner for setting the entire housing
20
in an N
2
atmosphere. In this exposure apparatus, the internal spaces of a lens barrel
2
and illumination optical system
4
are partitioned from the internal space (driving system space) of the housing
20
, and independently adjusted to an He atmosphere. Reference numerals
13
and
14
denote a reticle load-lock chamber and wafer load-lock chamber used to load a reticle and wafer into the housing
20
, respectively.
In general, a reticle is equipped with a pattern protection device called a pellicle. The pellicle prevents deposition of a foreign matter onto a reticle pattern surface, and suppresses the occurrence of defects caused by transfer of a foreign matter onto a wafer.
FIG. 3
is a schematic view showing the structure of a reticle with a pellicle. A pellicle
24
is adhered to the pattern surface of a reticle
23
with an adhesive agent or the like. The pellicle
24
is made up of a pellicle support frame (pellicle frame)
25
large enough to surround the reticle pattern, and a pellicle film
26
which is adhered to one end face of the pellicle support frame
25
and transmits exposure light. If a space (to be referred to as a pellicle space hereinafter) defined by the pellicle
24
and reticle
23
is completely closed, the pellicle film
26
may expand or contract due to the difference in atmospheric pressure b
LandOfFree
Device manufacturing-related apparatus, gas purge method,... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device manufacturing-related apparatus, gas purge method,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device manufacturing-related apparatus, gas purge method,... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3329329