Coating apparatus – Projection or spray type – Rotating work
Reexamination Certificate
1999-01-15
2002-05-21
Crispino, Richard (Department: 1734)
Coating apparatus
Projection or spray type
Rotating work
C118S320000, C118S679000, C118S684000, C118S685000, C118S699000, C118S710000, C239S068000, C239S071000, C239S119000, C222S071000, C222S108000, C222S571000
Reexamination Certificate
active
06391111
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a coating apparatus for coating a coating liquid such as a resist liquid onto a surface of an object to be treated such as a semiconductor wafer or the like.
2. Description of the Related Art
In the photolithography step for instance, in the manufacturing process of a semiconductor device, for instance, the resist coating treatment for forming a resist film on a surface of a semiconductor wafer (hereinafter refers to as “wafer”) is carried out, after an exposing treatment is carried out to the wafer thereon the resist is coated, a developing treatment is carried out.
FIG. 22
is a diagram showing diagrammatically a constitution of a resist liquid supply system of a conventional resist coating apparatus.
When an attention is paid to a device for coating a resist, in the conventional coating apparatus, as shown in
FIG. 22
, a resist liquid stored in a resist tank
201
is pumped out by a supplying pump
202
and stored in a buffer tank
203
once, then the resist liquid stored in the buffer tank
203
is sent by pressure towards a nozzle
205
by a discharging pump
204
, and by switching the flowing course of the resist liquid by a valve
206
disposed between the discharging pump
204
and the nozzle
205
, the timing of discharge of the resist liquid from the nozzle
205
is controlled.
The valve
206
employed here is an air operation valve which is driven through a compressed air and is provided with a structure in which the flowing courses on the sucking side and the discharging side are opened or closed therebetween by a cylinder operated by the compressed air, and switching of flowing in/stoppage of the compressed air is carried out by a solenoid valve
207
disposed between an air compressor which sends the compressed air and the valve
206
. This solenoid valve
207
has a structure that the solenoid is driven based on the electrical signals from a controller
208
to open or close the flowing course of the compressed air.
Further, the switching speed of the valve
206
is controlled by a speed controller
209
disposed between the solenoid valve
207
and the valve
206
. This speed controller
209
has a structure in which the width of the flowing course of the compressed air is adjusted by an amount of projection of a needle and the amount of projection of the needle is adjusted manually.
Incidentally, in order to form a resist film of excellent quality on a wafer, a predetermined amount of a resist liquid is dripped on an wafer revolving with a high speed and diffused due to a centrifugal force over the whole wafer, at the same time, the superfluous resist liquid is required to be removed from on the wafer. Therefore, rotation of the wafer, the discharging pump
204
and the valve
206
are required to be operated with the predetermined timings.
However, in the aforementioned conventional coating apparatus, there tends to occur a time lag between from the sending of the operational signal from the controller
208
up to the actual switching operation of the valve
206
.
This time lag is adjusted by use of the speed controller
209
. However, it varied due to the length of the flowing course or the individual difference of the valves themselves, accordingly the adjustment thereof is very difficult. Therefore, there was a problem that the timing of the discharge of the resist liquid deviated against the revolution of the wafer to induce occurrence of films of bad quality such as the films of the fluctuated thickness.
In addition, as shown in
FIG. 22
, in the case of the resist tank
201
being disposed below the floor, a buffer tank
203
is required to be disposed between from the resist tank
201
to the discharging tank
204
. However, when the buffer tank
203
is disposed, accompanying this, a liquid level sensor
211
becomes necessary. There occur such problems that it leads to the rise of the cost or larger size of foot print, and, due to an increase of the surface area which makes a contact with the air, the resist liquid tends to deteriorate.
SUMMARY OF THE INVENTION
The present invention was made to solve such problems as described above, an objective of the present invention is to provide a coating apparatus which can make as short as possible the time lag up to operation of the valve.
Another objective of the present invention is to provide a coating apparatus in which the discharging pump and the valve can be operated with the best timings.
Still another objective of the present invention is to provide a coating apparatus in which a switching valve and a suck back valve can be operated at the best timing.
The still another objective of the present invention is to provide a coating apparatus in which the rise of the cost and deterioration of the resist liquid can be prevented from occurring.
The coating apparatus of the present invention comprises a nozzle discharging a coating liquid to an object to be treated, a container for storing the coating liquid, a discharging pump which is disposed between the nozzle and the container and sends out the coating liquid in the container to the nozzle, a speed controlling means, disposed between the discharging pump and the nozzle, of controlling electrically the switching speed, and a controlling means for controlling the operation of the discharging pump.
The aforementioned coating apparatus, in which the valve is consisting of a switching valve and a suck back valve, may be provided with a controller exclusively controlling the operation of the switching valve and the suck back valve.
Further, the aforementioned coating apparatus may be further provided with a pressure detecting means for detecting the pressure of the coating liquid on the downstream side of the discharging pump, and the controlling means may be a means which controls the operation of the valve based on the detected pressure of the coating liquid.
Further, the coating apparatus, which is disposed between the container and the discharging pump, may be further provided with a supplying pump for supplying the coating liquid in the container to the discharging pump, and a pressure controlling means for controlling the pressure of the coating liquid of the down stream side of the supplying pump, wherein the controlling means may be a means for controlling the pressure of the supplying pump based on the operation of the discharging pump.
Further, the controlling means may be a means for controlling the pressure of the supplying pump and the timing of the operation of the valve based on the actions of the discharging pump.
The aforementioned device may further comprise a means for detecting the pressure of the coating liquid of the down stream side of the discharging pump, a supplying pump, which is disposed between the container and the discharging pump, for supplying the coating liquid in the container to the discharging pump, and, a means for controlling the pressure of the coating liquid of the down stream side of the supplying pump, wherein the controlling means may be a means which, based on the pressure detected by the pressure detecting means, controls the actions of the discharging pump and the valve, and at the same time, controls the pressure of the supplying pump based on the actions of the discharging pump.
REFERENCES:
patent: 5134962 (1992-08-01), Amada et al.
patent: 5405443 (1995-04-01), Akimoto et al.
patent: 5985357 (1999-11-01), Sanada et al.
patent: 6010740 (2000-01-01), Rutledge
patent: 6056998 (2000-05-01), Fujimoto
patent: 6062442 (2000-05-01), Yang et al.
patent: 63-236559 (1988-10-01), None
patent: 63-250124 (1988-10-01), None
patent: 2-156627 (1990-06-01), None
patent: 04-352316 (1992-12-01), None
patent: 09-253564 (1997-09-01), None
patent: 11-026377 (1999-01-01), None
Fujimoto Akihiro
Hasegawa Izumi
Ishizaka Nobukazu
Sakamoto Kazuo
Crispino Richard
Lorengo J. A.
Rader Fishman & Grauer
Tokyo Electron Limited
LandOfFree
Coating apparatus 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 apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2899567