Photography – Fluid-treating apparatus – Gaseous-treating
Reexamination Certificate
2000-08-09
2001-11-06
Rutledge, D. (Department: 2851)
Photography
Fluid-treating apparatus
Gaseous-treating
C396S611000
Reexamination Certificate
active
06312171
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-228671, filed Aug. 12, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing apparatus for performing substrate processing such as developing processing and the like, for example, for a substrate and a method thereof.
A mask for forming a predetermined pattern on a front face of a semiconductor wafer (hereinafter, referred to as “wafer”) or a glass substrate (LCD substrate) of a liquid crystal display is obtained by applying a resist to a front face of a substrate such as a wafer or the like and then irradiating rays of light, electron rays, ion beams, or the like to the resist surface, and performing developing. The developing processing here is performed by dissolving portions irradiated with light or the like or portions without such irradiation in an exposure process with use of an alkaline water solution or the like, and conventionally it has been performed by a method shown in FIG.
18
.
In the conventional method, a substrate, for example, a wafer W is suction-held, for example, on a spin chuck
11
having a vacuum suction function, and a supply nozzle
13
in which many discharge holes
12
are arranged along a length corresponding to a diameter of the wafer W is positioned so that the discharge holes
12
are placed above the wafer surface by 1 mm at the central portion of the wafer W. Then, a developing solution
10
is supplied to the center of the wafer surface from the discharge holes
12
to thereby perform solution heaping as shown in FIG.
18
. Subsequently, the wafer W is made to half-rotation (180-degree rotation) while the developing solution
10
is supplied from the discharge holes
12
.
Thus, the developing solution which has been first heaped at the central portion of the wafer is spread out and simultaneously the developing solution
10
is newly supplied, resulting in formation of a solution film of the developing solution
10
with a predetermined thickness over the entire wafer surface. After the heaping of the developing solution
10
is performed, the wafer W is left standing, for example, for 60 seconds, and then a rinse solution is supplied onto the wafer surface to rinse away the developing solution, whereby the developing is performed.
Explaining briefly a conventional developing apparatus in which the above-described developing processing is performed with reference to
FIG. 19
, the spin chuck
11
is surrounded by a cup
14
for preventing the developing solution
10
from splashing out. A filter unit
15
formed by combination of a filter and a fan is provided above the cup
14
and a current plate
16
in which many air holes
16
a
are formed is provided between the filter unit
15
and the cup
14
.
An exhaust passage
17
is connected to the cup
14
, and part of air which has been exhausted by the exhaust passage
17
is circulated to be supplied to the filter unit
15
via a filter apparatus not shown for eliminating impurities and performing adjustment to a predetermined temperature and humidity to be supplied from the filter unit
15
toward the cup
14
while forming downflow. The air from the filter unit
15
from which impurities have been eliminated and which has been adjusted to the predetermined temperature and humidity passes through the current plate
16
, thereby being supplied to the cup
14
side with being increased in uniformity. The downflow of air, which is adjusted with high accuracy, is formed to make developing solution temperatures and evaporation speeds uniform.
However, for example, in the case of using an ion beam resist, developing unevenness occurs in the above-described developing method, whereby developed line width varies depending on the position, which causes a disadvantage of, for example, an irregularity in line width of about 4 nm between an area close to the center of the wafer and a rim portion thereof. From a study of a cause of the above, it is conceivable that temperature distribution occurs in the developing solution
10
within the plane of the wafer because degrees of proceeding of the developing depends on the temperature of the developing solution
10
.
In other words, the developing solution
10
is adjusted to a temperature of, for example, about 23° C., but water contained in the developing solution
10
evaporates while the wafer W is subjected to the solution heaping and then left standing, whereby latent heat in the developing solution
10
is lost, and thus the temperature of the developing solution
10
falls with time. Meanwhile, it is conceivable that the temperature of the rim area falls to be lower than that of the area close to the center of the wafer W within the plane due to the formation of the downflow of the aforesaid air which has been adjusted with high accuracy. More specifically, by the formation of the downflow, air currents flow from above seeing from the wafer W. The air currents which have blown against the wafer W flow toward the outer periphery side thereof along the wafer face as shown in
FIG. 20
, whereby an airflow amount to the rim area becomes larger than that to the area close to the center. Therefore, it is presumed that heat of evaporation in the rim area is larger than that in the area close to the center within the plane of the wafer W, so that an amount of heat radiation in the rim area becomes larger than that in the area close to the center, resulting in a high degree of fall in temperature of the rim area.
Therefore, it is presumed that temperature difference in the developing solution
10
of about 1° C. occurs between the area close to the center of the wafer and the rim portion at the start of a rinse, whereby there occurs unevenness in the developing state, resulting in occurrence of a bad influence of variations in finished measurements.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a developing apparatus for enhancing uniformity of processing by making temperatures in a developing solution uniform within a plane of a substrate during developing to thereby prevent occurrence of developing unevenness because of temperature difference in the developing solution and a method thereof.
To solve the aforesaid disadvantages, a developing apparatus of the present invention is a developing apparatus for heaping a developing solution to a front face of a substrate to perform developing in an atmosphere in which an air stream toward the front face of the substrate is formed, comprising: a substrate holding section for holding the substrate; a supply section for supplying the developing solution to the substrate; a first current plate provided on the front face side of the substrate held by the substrate holding section to oppose the substrate and in which first air holes are formed; and a second current plate provided to oppose the first current plate to move in a plane direction relative to the first current plate and in which second air holes are formed, wherein the first current plate and the second current plate are moved relative to each other in the plane direction to overlap the first air holes and an area of the second current plate where the second air holes are not formed in a direction orthogonal to the plane direction to thereby adjust sizes of the first air holes and control an airflow amount of an air current blowing against the front face of the substrate.
In such a developing apparatus, the airflow amount of air an current blowing against the front face of the substrate can be adjusted, whereby heat of evaporation of the developing solution on the substrate which changes in accordance with the amount of airflow to the front of the substrate can be adjusted, with the result that the temperature of the developing solution on the substrate can be controlled.
Concretely, making the sizes of the first air holes smaller while the developing of the front fac
Hamada Masahito
Matsuyama Yuji
Rader & Fishman & Grauer, PLLC
Rutledge D.
Tokyo Electron Limited
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