Fluent material handling – with receiver or receiver coacting mea – With material treatment – Heating or cooling
Reexamination Certificate
2003-04-15
2004-11-16
Maust, Timothy L. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
With material treatment
Heating or cooling
C141S065000, C141S069000, C141S085000
Reexamination Certificate
active
06817387
ABSTRACT:
BACKGROUND OF THE INVENTION
This application claims the priority of Korean Patent Application No. 2002-22205, filed on Apr. 23, 2002, and Korean Patent Application No. 2002-22700, filed on Apr. 25, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a fluid supplying system for LCD (liquid crystal display) manufacturing equipment, and more particularly, to a wet processing bath for LCD manufacturing equipment and a fluid supplying system including the wet processing bath.
2. Description of the Related Art
Recently, sizes of LCD panels have been becoming larger and resolutions thereof have been becoming higher. As technical problems concerning, e.g., higher contrast, wider viewing angle, etc., are being solved, conventional CRT (Cathode Ray Tube) devices are rapidly being replaced by LCD devices. Particularly, such a trend is accelerated in relation to the development of active matrix type TFT-LCD (Thin Film Transistor Liquid Crystal Display) devices and wider applications thereof. The active matrix type TFT-LCD is characterized in that switching elements called TFT's are formed in correspondence to each pixel and the pixels are individually controlled.
Generally, glass is used as a substrate material in a process for fabricating transistors formed in correspondence to each pixel of a TFT-LCD device, i.e., a thin film transistor fabrication process. Since the melting point of glass is relatively low, a processing temperature of the thin film transistor fabrication process is limited to the range of 300 to 500° C. Further, in order to embody a circuit on the glass substrate, unit processes of a typical semiconductor fabrication process are applied to the thin film transistor fabrication process. Therefore, lots of wet processes using fluid are adapted to the thin film transistor fabrication process. In the wet processes, such as cleaning, stripping, wet etching, or developing, a fluid such as a chemical solution or deionized water is used.
FIG. 1
is a schematic diagram of a conventional fluid supply system used in manufacturing LCD devices.
Referring to
FIG. 1
, the fluid supplying system includes a plurality of baths
121
,
122
,
123
having fluid collection units (not shown), a storage tank
130
, a pump
140
, a fluid supplement unit
150
, and pipelines (not shown) for connecting the foregoing elements. Unit process, e.g., cleaning, etching, or developing, is performed in the baths
121
,
122
, and
123
and is referred to 1
st
, 2
nd
, or 3
rd
process unit in FIG.
1
. The baths
121
,
122
, and
123
are connected to the storage tank
130
and the pump
140
via the pipelines.
Although three baths
121
,
122
, and
123
are shown in
FIG. 1
, there is no limit in the number of baths connected to the pump
130
. While the size of the storage tank
130
and the arrangement of the baths are determined according to the number of the baths
121
,
122
, and
123
equipped in the system, the baths
121
,
122
, and
123
are generally arranged in a structure where minimum pipelines are used so that a loss of pressure or heat of the fluid can be minimized.
The fluid is supplied to the process units
111
,
112
, and
113
included in the baths via the pump
140
, and the used fluid is collected in the baths
121
,
122
, and
123
. The fluid drained from the baths
121
,
122
, and
123
includes by-products of each process, such as contaminants, etching residuals, or developing residuals. The fluid collected in the baths
121
,
122
, and
123
is recollected and stored in the storage tank
130
via the pipelines. During this process, some of the residual materials can be filtered.
As shown in
FIG. 1
, since a single storage tank
130
is used in connection with a plurality of baths
121
,
122
, and
123
, the size of the storage tank
130
should be large in that a huge amount of fluid can be stored therein. Typically, the storage tank
130
may include a heater (not shown). The heater adequately raises the temperature of the fluid so that the unit processes can be performed efficiently in the process units
111
,
112
, and
113
.
The fluid stored in the storage tank
130
is supplied again to the process units
111
,
112
, and
113
in the baths via the pump
140
. The pipelines connecting the pump and the baths
121
,
122
, and
123
include valves (not shown), filters (not shown), and regulators (not shown). Fluid is supplied from the fluid supplement unit
150
in addition to the storage tank
130
. Since the fluid is adhered to the substrates and drained together with the substrates outside the baths
121
,
122
, and
123
during the processes, the fluid supplement unit
150
supplements the drained fluid. The fluid supplement unit
150
may also include a heater (not shown).
FIG. 2
is a more detailed diagram of the conventional fluid supply system that is applied to cleaning equipment, in which only one bath
221
is represented.
FIG. 2
simply and schematically shows the structure of a cleaning unit
211
placed in the bath
221
, as well as valves
261
, filters
262
, regulators
263
, and flow meters
264
included in pipelines, and may be different from the structure of a cleaning unit and the arrangements of pipelines used in actual cleaning equipment.
Apparent from
FIGS. 1 and 2
, the conventional fluid supplying system is characterized in that a bath is provided for each process unit and only one storage tank is used for a plurality of baths. Accordingly, the distance between the baths and the storage tank and that between the pump and baths are fairly long. Thus, the temperature and the pressure of fluid can be lowered while passing through the long pipelines.
Due to the thermal loss in the conventional fluid supplying system, additional costs are required in equipping large-capacity pumps to reduce the thermal loss. Further, it is hard to supply fluid at an optimum temperature. In addition, since a great amount of fluid should be supplied to each bath, a pump having a large capacity is required.
Furthermore, long pipelines are required for connecting each element of the conventional fluid supplying system, and the arrangements of the pipelines and the structure of the system are very complex. For example, numerous connecting elements, such as filers, valves, elbows, reducers, T's, etc., should be used and be arranged in a complicated manner. Particularly, in a case where the processing fluid is a highly toxic chemical, such as hydrochloric or nitric acid, the connecting elements used in the pipelines are very expensive, and accordingly, the cost and expenses for manufacturing and maintaining the fluid supplying system are increased.
Moreover, in the conventional fluid supplying system, the amount of fluid supplemented from the fluid supplement unit is very small in comparison to the amount of the fluid used in the process units. If the amount of the processing fluid is great, it is difficult to prevent the gradual increase in the opacity of the fluid even though clean fluid is supplemented from the outside. If the opacity of the fluid increases, the substrates may be contaminated and, thus, the production yield of the LCD devices will be decreased. In order to prevent the contamination of the substrates and the decrease of the production yield, it is required to periodically replace all of the fluid stored in the storage tank with fresh fluid.
Meanwhile, the body of the bath
221
used in the fluid supplying system is generally made of durable materials such as steel, namely, SUS metal or Polyvinyl Chloride (PVC), through welding or coupling since wet processes should be performed to remove organic or inorganic substances, metal ion surface films, corpuscles, or contaminants adhered on the surface of the LCD device.
In order to reduce the process time, the concentration of the chemical fluid used in the wet processes for manufacturing the LCD devices is becoming higher. However, due to the high concentr
Kim Sang-Ho
Lee Sok-Joo
Park Yong-Seok
Display Manufacturing Service Co., Ltd.
Maust Timothy L.
Rothwell Figg Ernst & Manbeck
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