Coating apparatus – Projection or spray type – With mask or stencil
Reexamination Certificate
2002-09-13
2004-07-13
Crispino, Richard (Department: 1734)
Coating apparatus
Projection or spray type
With mask or stencil
C118S504000, C118S323000
Reexamination Certificate
active
06761125
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a system for supplying a coating liquid to various substrates, such as reticle substrates for photomasks, semiconductor wafers, or glass substrates for liquid crystal displays, to form a liquid film by the coating liquid.
DESCRIPTION OF RELATED ART
In a process for producing semiconductor devices and LCDs, a resist processing on a substrate to be processed is carried out by a technique called photolithography. In this processing, an exposure processing is carried out using a reticle substrate on which a predetermined mask pattern is formed. The formation of the mask pattern on the surface of the reticle substrate is carried out by a series of processes for applying a predetermined chemical (coating liquid) on the surface of a glass substrate to form a liquid film, and thereafter, exposing the liquid film to carry out a development to obtain a desired pattern.
As a conventional method for forming the above described liquid film, there has been adopted the spin coating method for holding a substrate in a horizontal state and rotating the substrate about a vertical axis and for supplying a coating liquid toward the center of the substrate from top to diffuse the coating liquid over the whole surface of the substrate by centrifugal force. However, in this method, there is a problem in that the periphery of the substrate easily becomes dirty since the coating liquid extends outwards, so that particles are easily produced from the coating liquid adhering to the peripheral portion. If particles adhere to the reticle substrate, the shadow of the particles becomes the shape of a circuit pattern as it is, so that it is required to avoid the adhesion of particles. As this measure, for a reticle substrate
11
having a zinc oxide layer
12
and a coating liquid layer
13
for forming a mask pattern as shown in
FIG. 20
, it is considered that it is effective to expose zinc oxide at the peripheral portion
14
of the substrate to be grounded, for example, in order to prevent the substrate from being charged during exposure by electron beams. However, the grounding method can not be adopted since the coating film is formed on the whole surface of the substrate in the case of the spin coating method.
Therefore, the inventor has studied that a coating device shown in
FIG. 21
is used for carrying out a coating process. In the figure, reference number
11
denotes a rectangular reticle substrate which is horizontally held by a substrate holding portion (not shown) movable in Y directions. Above the reticle substrate
11
, there are provided a plate
16
formed with a slit
15
extending in X directions, and a nozzle portion
17
for supplying a mask pattern forming coating liquid to the reticle substrate
11
, which is arranged below the plate
16
, via the slit
15
. Reference numbers
18
a
and
18
b
are a pair of shutters which are provided on both sides of a slit
14
above the plate
16
and which have, e.g., a tray shape, so as to be capable of recovering the coating liquid dropping from the nozzle portion
17
moving above the shutters.
During a coating process, the nozzle portion
17
is reciprocated (scanned) in X direction from above the shutter
18
a
to above the shutter
18
b
, and the reticle substrate
11
arranged below the nozzle portion
17
is intermittent-fed in Y directions, so that the lines of the coating liquid having a length corresponding to the slit
15
are closely arranged on the surface of the reticle substrate
11
as shown in FIG.
22
. The length of the slit
15
is determined so as to prevent the coating liquid from being supplied to the periphery of the reticle substrate
11
and so as to expose the underlaying zinc oxide. The coating liquid which should be originally coated on the periphery of the reticle substrate is recovered by the shutters
18
a
and
18
b.
In the method for scanning the nozzle portion to coat the coating liquid, the reticle substrate is not rotated, so that there are advantages in that it is possible to inhibit the peripheral portion from being contaminated, that it is possible to apply the coating liquid on the whole surface of the reticle substrate while exposing zinc oxide, and that it is possible to make good use of the coating liquid. However, during the supply of the coating liquid, there are some cases where part of the coating liquid hitting on the surface of the reticle substrate and the top face (liquid receiving face) and side faces (the faces of the shutters
18
a
and
18
b
facing each other) of the shutters splashes to fly off as mist, which becomes particles adhering to the surface of the reticle substrate. Particularly on the side face portions of the shutters on which the coating liquid first hits during the scanning of the nozzle portion, mist is easily produced by the shock of the hitting of the coating liquid. In addition, the downward flow of clean air is formed in the coating device, so that there is also a problem in that the mist produced around the shutters, together with the downward flow, easily flows toward the reticle substrate via the slit.
In addition, the thickness of the thin film of the coating liquid formed on the surface of the shutters gradually increases by repeating the coating process, and a part thereof is peeled off to cause particles. Therefore, the shutters must be removed in predetermined timing. For example, the shutters must be replaced with cleaned shutters, and the removed shutters must be cleaned, so that there is a problem in that work is troublesome. In addition, it is required to ensure a space required to clean the shutters, so that there is also a problem in that the system increase in size.
SUMMARY OF THE INVENTION
The present invention has been made in the circumstances, and it is an object of the present invention to provide a technique for scanning a nozzle portion in lateral directions and moving a substrate in longitudinal directions to inhibit particles from adhering to the surface of the substrate in a system for forming a liquid film of a coating liquid on the surface of the substrate. It is another object of the present invention to provide a technique for improving the yields of a coating film formed on the surface of a substrate.
According to one aspect of the present invention, a coating film forming system comprises: a substrate holding portion for horizontally holding a substrate; a first driving part for moving the substrate holding part in longitudinal directions; a nozzle portion, provided so as to face the substrate held on the substrate holding portion, for discharging a coating liquid to the substrate; a second driving part for moving the nozzle portion in lateral directions; a plate which has a slit being open so as to have a width corresponding to a lateral width of a coating region of the substrate and which is provided between the nozzle portion and the substrate; and a suction mechanism for sucking a suspended matter over a range corresponding to the width of the slit via a suction port which is provided in the vicinity of the slit, wherein the nozzle portion is moved in the lateral directions to linearly apply the coating liquid in linear coating regions on the substrate via the slit, and thereafter, the substrate is intermittently moved so as to closely arrange the linear coating regions in the longitudinal directions, to form a coating film.
With this construction, fine suspended matters, such as the mist of the coating liquid flying during a coating process, can be recovered by the slit, so that it is difficult to contaminate the substrate when the coating film is formed. If the suction port is provided above the plate in the vicinity of the slit, fine suspended matters, such as the mist of the coating liquid, can be recovered by the slit before flowing into the slit, so that it is difficult to contaminate the substrate when the coating film is formed. If the suction ports are provided above and below the plate in the vicinity of the slit, fine suspended matters, such as the mist of
Kawafuchi Yoshiyuki
Kitano Takahiro
Koga Norihisa
Takei Toshichika
Crispino Richard
Tadesse Yewebdar
Tokyo Electron Limited
LandOfFree
Coating film forming system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Coating film forming system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating film forming system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3204629