Viscous fluid discharging apparatus for manufacturing semiconductors having a removable bubble capturing portion

A viscous fluid discharging apparatus is provided for removing air bubbles introduced during the passing of the viscous fluid before being supplied to the substrate. A viscous fluid discharging apparatus according to the present invention includes a viscous fluid storing container, a viscous fluid supplying pump, a viscous fluid filter, and a viscous fluid discharging mechanism provided with a final air bubble filtering means. The fluid material discharging mechanism includes a connecting portion formed on an end of a temperature adjusting mechanism connected to an outlet of the fluid material supplying pump, and a discharging gun. The discharging gun has a sealed joining portion for being sealed and joined to the connecting portion, an air bubble capturing portion for capturing air bubbles from within the viscous fluid, and a viscous fluid path for moving the viscous fluid to an outlet in a sealed state.

FIELD OF THE INVENTION 
The present invention relates to viscous fluid discharging apparatus in 
which air bubbles are restrained during the discharging of a viscous 
fluid. 
BACKGROUND OF THE INVENTION 
Semiconductor manufacturing equipment, for example a photoresist coating 
apparatus, has a discharging gun for discharging a fluid having a certain 
level of viscosity. If a fluid having a viscosity such as a photoresist 
contains air bubbles during discharging, the fluid may cause a coating 
defect. As illustrated in FIG. 1, a conventional viscous fluid discharging 
apparatus includes storage container 1 for containing and storing a 
viscous fluid, viscous fluid pump 2 for supplying the viscous fluid from 
storage container 1, viscous fluid filter 3 connected to an outlet of 
viscous fluid pump 2 for filtering off impurity materials and air bubbles 
contained in the viscous fluid, and viscous fluid discharging mechanism 4 
for supplying the viscous fluid to relevant regions. 
Particularly, viscous fluid discharging mechanism 4 typically has a 
sectional constitution as illustrated in FIG. 2. Viscous fluid discharging 
mechanism 4 includes a temperature adjusting means having path 21 for 
temperature adjusting fluid 22 on the outside of discharging gun 20, for 
maintaining the viscous fluid at a certain temperature range when it is 
discharging from discharging gun 20. 
For example, to look into a process for spreading photoresist onto a 
substrate, if a carrier containing a wafer is loaded to a wafer supplying 
portion, then the wafer automatically is moved to a photoresist coating 
section, with the result that the wafer is mounted on a vacuum chuck. 
Consequently, the wafer is rotated, while the viscous fluid supplying pump 
is activated. Sometimes, the pump is activated in a state with the wafer 
being stopped without rotation. When the viscous fluid supplying pump is 
activated, the viscous fluid is sucked up from the viscous fluid storing 
container to pass through the viscous fluid supplying pump, the viscous 
fluid filter and the final viscous fluid discharging mechanism to be 
discharged so as to coat the wafer. 
In this process, when the viscous fluid together with residue air bubbles 
passes through the viscous fluid supplying pump, most of the air bubbles 
are removed by the viscous fluid filter. However, part of air bubbles 25 
pass through the viscous fluid filter, or air can be introduced into the 
viscous fluid due to the fact that the sealing of the joining portion of 
the viscous fluid discharging apparatus is not perfect. In this case, 
there is no further means for removing the air bubbles, and, therefore, 
the viscous fluid containing the air bubbles is discharged to the wafer, 
with the result that coating defects are produced. 
SUMMARY OF THE INVENTION 
The present invention is intended to address the above-described 
disadvantages of the conventional technique. 
Therefore, it is an object of the present invention to provide a viscous 
fluid discharging apparatus in which an additional means is installed for 
removing air bubbles introduced during the passing of the viscous fluid 
before being supplied to the substrate, so that the finally supplied 
viscous fluid contains minimal air bubbles. 
In achieving the above and other objects, a viscous fluid discharging 
apparatus according to the present invention includes a viscous fluid 
storing container, a viscous fluid supplying pump, a viscous fluid filter, 
and a viscous fluid discharging mechanism provided with a final air bubble 
filtering means. 
The fluid material discharging mechanism includes a connecting portion 
formed on an end of a temperature adjusting mechanism connected to an 
outlet of the fluid material supplying pump, and a discharging gun. The 
discharging gun has a sealed joining portion for being sealed and joined 
to the connecting portion, an air bubble capturing portion for capturing 
air bubbles from within the viscous fluid, and a viscous fluid path for 
moving the viscous fluid to an outlet in a sealed state. 
The sealed joining portion includes a tightening band for joining the 
viscous fluid path to the viscous fluid outlet, and the air bubble 
capturing portion includes a space forming portion on the upper portion of 
the viscous fluid path to form a plurality of small spaces.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 3 is a sectional view of a viscous fluid discharging mechanism of a 
viscous fluid discharging apparatus according to the present invention. 
A viscous fluid discharging mechanism according to the present invention is 
constituted such that there is formed connecting portion 31 for connecting 
discharging gun 30 to the end of temperature adjusting mechanism 21. 
Discharging gun 30 includes a sealed joining portion for being sealed and 
joined to connecting portion 31, an air bubble capturing portion for 
capturing air bubbles from within the viscous fluid, and a viscous fluid 
path for moving the viscous fluid to the outlet in a sealed state. 
The viscous fluid discharging mechanism is connected to the viscous fluid 
discharging outlet which is connected to a fluid material filter, a fluid 
material supplying pump and a fluid material storing container in the 
upstream direction. The fluid material having a certain degree of 
viscosity may be used in the manufacture of semiconductor devices. 
Particularly, the apparatus of the present invention may be used in 
spreading photoresist. 
For the sealed joining portion for sealing and joining the viscous fluid 
path to the viscous fluid outlet, there is used tightening band 32 which 
is tightened by means of screw 33. In alternative embodiments, other 
sealed joining mechanisms such as a threadable joining, a flange joining 
or the like are used. 
Since air bubbles tend to move upward during the moving of the viscous 
fluid, an air bubble capturing portion is disposed upon the viscous fluid 
path. This air bubble capturing portion consists of pore forming portion 
39 which includes small pores 38. 
This air bubble capturing portion may be provided in various forms, and may 
be conveniently provided in the form of a furrowed tube which performs a 
role as a viscous fluid path and an air bubble capturer. If the furrowed 
tube is flexible, it is convenient to move the discharging outlet during 
the semiconductor manufacturing process. 
The shape of the furrows may be an angled type or a round type. Even if 
furrows are not provided, pockmarks may be provided, so that the air 
bubbles may be captured within the pits of the pockmarks. 
The process of coating photoresist (which is a viscous fluid) on a wafer 
using a viscous fluid discharging apparatus of the present invention will 
now be described. 
First, a carrier loaded with a plurality of wafers is installed on a wafer 
supplying portion. 
Then the wafers move one by one into the coating portion. A wafer is placed 
on a vacuum chuck so as for the wafer to be firmly secured by the vacuum 
chuck, the wafer being rotated or in a still state. The viscous fluid 
supplying pump is activated so that photoresist is discharged, and that 
the wafer is coated with photoresist. When photoresist is discharged, if 
the air bubbles are not completely removed but partly remain to move 
toward the viscous fluid outlet, or if the joining portion of the viscous 
fluid is not perfectly sealed so as for air to be introduced to form air 
bubbles, then the air bubbles are inhibited from moving forward, because 
the viscous fluid discharging mechanism is provided in the form of a 
furrowed tube. That is, the originally included air bubbles and newly 
introduced air bubbles due to a defect in the viscous fluid discharging 
mechanism tend to float on the viscous fluid during the flow of the 
viscous fluid due to the difference in specific gravity between the 
viscous fluid and the air bubbles. Therefore, the furrowed spaces of the 
furrowed tube tend to capture floating air bubbles 25, and only viscous 
fluid 24 with air bubbles removed is discharged. 
The furrowed viscous fluid discharging mechanism may be detached from the 
joined portion, and disassembled, assembled and replaced. Therefore, it 
may be periodically cleaned, and accordingly, it is very convenient. 
According to the present invention as described above, the viscous fluid 
discharging mechanism finally removes the air bubbles from the viscous 
fluid prior to discharge, with the result that coating defects are 
reduced. Further, the viscous fluid discharging mechanism may be 
disassembled, assembled and replaced after being used for a certain period 
of time, and, therefore, the formation of particles may be inhibited. 
Further, the phenomenon of the viscous fluid discharging mechanism being 
clogged is improved, and the undesirable variation in the discharge rate 
and discharge pressure also are improved. 
Although various preferred embodiments of the present invention have been 
disclosed for illustrative purposes, those skilled in the art will 
appreciate that various modifications, additions and/or substitutions are 
possible without departing from the scope and spirit of the present 
invention as disclosed in the claims.