Ventilation – Clean room
Reexamination Certificate
2000-09-27
2003-04-15
Boles, Derek (Department: 3749)
Ventilation
Clean room
C414S935000, C414S940000
Reexamination Certificate
active
06547660
ABSTRACT:
TECHNICAL FIELD
The present invention relates to semiconductor manufacturing facilities and, more particularly to a semiconductor manufacturing facility including semiconductor manufacturing equipment which generates heat in operation in manufacture of semiconductor devices and a semiconductor manufacturing apparatus installed in the semiconductor manufacturing facility and a semiconductor manufacturing method.
BACKGROUND ART
Semiconductor manufacturing equipment is installed in a clean room in which clean air is circulated, and located in an environment in which a surface of a silicon wafer on which a semiconductor manufacturing circuit is formed is not contaminated. AN air filter is installed on the ceiling of the clean room so that the air filtered by the air filter flows around the semiconductor manufacturing equipment. Supply of air to the air filter is performed by a blower mounted on an upstream side of the air filter. The air in the clean room is introduced into a return passage provided to a floor or a side wall, and a temperature and humidity is adjusted therein. Thereafter, the air returns to a plenum chamber above the ceiling board, and is supplied to the clean room after dust is removed therefrom by the air filter. First, dust having a large particle diameter is removed from the air supplied to the clean room. Thereafter, metal ions such as natrium, negative ions such as sulfate ions and ammonia ions are removed by being subjected to water cleaning or using a chemical filter. The humidity and temperature of the treated is adjusted, and fine dust is removed, and the air is supplied to the plenum chamber.
As mentioned above, a large amount of energy is consumed as a power for cleaning process of air and a power for controlling temperature and humidity so as to produce the air used for a clean room.
Many sets of semiconductor manufacturing equipment use heat for raising temperature of wafers in a manufacturing process. One of those sets of semiconductor manufacturing equipment is a vertical heat treatment apparatus, which is a batch type heat treatment apparatus.
FIG. 1
is a cross-sectional view of a conventional vertical heat treatment apparatus with an air cooling apparatus. The vertical heat treatment apparatus is installed in a clean room
1
.
In
FIG. 1
, a heating furnace
12
, which corresponds to the semiconductor manufacturing equipment, is provided in an upper portion of a housing
11
, which forms an outer covering part of the apparatus. The heating furnace
12
comprises: a cylindrical quartz pipe
13
which is a reaction tube having an open lower end; a heater
14
arranged to surround the quarts pipe
13
; and a heat insulating layer
15
comprising an insulating material provided to surround the heater
14
and a water cooling pipe. The cooling water is supplied trough an inlet pipe
15
a
, and exits from an outlet pipe
15
b
. A lower part of the housing
11
constitutes a wafer loader chamber
10
, and a support tool
17
, on which a wafer is placed, is moved upward by an elevator
16
so that the support tool
17
can be carried in the quartz tube
13
.
In the thus-structured vertical heat treatment apparatus, when an oxidation process is applied to the wafer, for example, since inside the heating furnace
12
reaches a temperature as high as 1000° C., a heat inside the heating furnace
12
is emitted to outside the insulating layer
15
even if the heating furnace
12
is covered by the heat insulating layer
15
. After the oxidation process is completed, the high-temperature wafer placed on the wafer boat in the heating furnace
12
is moved downward by the elevator, and is taken out of the heating furnace
12
. At this time, the high-temperature According to this cause, the air surrounding the heating furnace
12
and the air in the wafer loader chamber
10
, when the wafer is taken out, reach several ten degrees. Due to the heat, the air in the periphery of the heat treatment apparatus is warmed, and the temperature in the clean room
1
is raised. Conventionally, in order to prevent the temperature of the clean room
1
increased from being raised, the air in the clean room is exhausted as follows.
A horizontal separation board
21
is provided between the upper portion and the lower portion of the housing
11
, and, in an area above the separation board
21
, the air in the clean room
1
is taken in between the heating furnace
12
and the housing
11
through air intake ports
22
and
23
, and the air is exhausted through an exhaust duct
24
provided in the upper portion of the housing
11
. Additionally, in an area under the separation board
21
, the air in the clean room
1
is taken in the wafer loader chamber
10
, and the air is exhausted trough an exhaust duct
25
. A fan
18
is provided in the wafer loader chamber
10
. The fan
18
circulates the air in the wafer loader chamber
10
, and the air in the clean room
1
is mixed to the circulated air. It should be noted that the exhaust duct
25
is provided along the ceiling of the clean room, and is connected to an exhaust line of the plant.
As mentioned above, the heat emitted from the heating furnace
12
is released outside the clean room
1
by passing through the exhaust ducts
24
and
25
. However, a part of heat emitted from the heating furnace
12
is released outside the clean room by transmitting walls of the exhaust ducts
24
and
25
. Accordingly, the part of heat emitted from the heating furnace
12
is released outside the clean room by a cooling facility provided in the circulation passage (return passage) in the clean room
1
.
The present inventors took a measurement of an amount of energy consumed by a dry coil (cooling coil), which is the cooling facility for cooling the air in the clean room
1
(the clean room
1
is actually a large room although drawn as a small room in
FIG. 2
) while performing exhaust according to the above-mentioned conventional exhaust method, in a state in which the heating furnace
12
is being operated.
In
FIGS. 2
,
3
indicates a laboratory;
1
indicates the clean room provided in the laboratory
1
;
32
indicates an air introducing pipe;
33
indicates a temperature and humidity adjusting part (external adjusting machine);
34
indicates an air circulation passage formed under the floor and an outer side of a side wall of the clean room; F indicates an air filter;
35
indicates a dry coil;
35
a
indicates a cooling part for cooling a coolant flowing in the dry coil
35
;
36
indicates a separation enclosure (corresponding to the housing
11
of
FIG. 1
) accommodating a vertical heat treatment apparatus;
37
indicates an exhaust duct (corresponding to the exhaust duct
24
of FIG.
1
);
38
indicates an exhaust fan;
39
a
indicates a cooling-water passage for cooing the heating furnace; and
39
b
indicates a facility for cooling the cooling water.
That is, after the outside air is taken in through the air introducing pipe
32
and the temperature and humidity of the air is adjusted by the temperature and humidity adjusting part (external adjusting machine)
33
, the air is supplied to the clean room
1
via the filter F. The temperature of the air in the clean room
1
is maintained, for example, at 23° C. by the dry coil
35
while being circulated through the circulation passage
34
. In side the heating furnace of the vertical heat treatment apparatus is raised to, for example, a predetermined temperature of 1000° C., and the heat released outside the heating furnace is released outside the laboratory through the exhaust duct
37
(the ducts
24
and
25
of
FIG. 1
are collectively indicated by a single path). The heat released outside the heating furnace 1) escapes outside through the exhaust duct
37
; 2) transmits inside the clean room
1
through the wall of the exhaust duct
37
or the separation enclosure
36
and is removed by the dry coil
35
; or 3) is removed by the cooling water of the cooling-water passage
39
a
. In 1), 2) and
39
, an energy consumption for removing the heat transmitted from the h
Kobayashi Sadao
Ohmi Tadahiro
Suenaga Osamu
Boles Derek
Pillsbury & Winthrop LLP
Tokyo Electron Limited
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