U.S. patent application number 09/932942 was filed with the patent office on 2002-02-28 for heat-processing apparatus and method of semiconductor process.
Invention is credited to Kato, Kazuhiko.
Application Number | 20020025688 09/932942 |
Document ID | / |
Family ID | 18741519 |
Filed Date | 2002-02-28 |
United States Patent
Application |
20020025688 |
Kind Code |
A1 |
Kato, Kazuhiko |
February 28, 2002 |
Heat-processing apparatus and method of semiconductor process
Abstract
A vertical heat-processing apparatus includes a surrounding
member, which surrounds a process chamber and a heater. The
surrounding member forms a heating space around the process
chamber. The heating space has zones juxtaposed in a vertical
direction. Temperature sensors are arranged to detect temperatures
respectively representing the zones. Supply pipes are arranged to
respectively supply a cooling gas to the zones. The supply pipes
are respectively provided with valves controlled by a controller.
The controller adjusts opening degrees of the valves such that a
flow velocity of the cooling gas in a first zone having a lower
cooling rate becomes higher than a flow velocity of the cooling gas
in a second zone having a higher cooling rate used as a
reference.
Inventors: |
Kato, Kazuhiko; (Esashi-shi,
JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Family ID: |
18741519 |
Appl. No.: |
09/932942 |
Filed: |
August 21, 2001 |
Current U.S.
Class: |
438/758 ;
432/239; 432/241; 432/247 |
Current CPC
Class: |
H01L 21/67109
20130101 |
Class at
Publication: |
438/758 ;
432/239; 432/241; 432/247 |
International
Class: |
H01L 021/31; H01L
021/469 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 23, 2000 |
JP |
2000-252249 |
Claims
What is claimed is:
1. A heat-processing apparatus for a semiconductor process in which
a plurality of target substrates are simultaneously subjected to a
heat-process, the apparatus comprising: a process chamber, which
accommodates the target substrates; a holder, which holds the
target substrates with a gap therebetween in the process chamber; a
heater disposed around the process chamber, which heats an interior
of the process chamber through a sidewall of the process chamber; a
surrounding member, which surrounds the process chamber and the
heater, and forms a heating space around the process chamber, the
heating space comprising a plurality of zones juxtaposed in a
direction in which the target substrates are arrayed; a plurality
of the temperature sensors, which detect temperatures respectively
representing the zones; a cooling mechanism, which forms flows of a
cooling gas respectively in the zones, and cools the zones; and a
controller, which controls the cooling mechanism on the basis of
temperatures detected by the temperature sensors when the process
chamber is cooled, such that a flow velocity of the cooling gas in
a first zone having a lower cooling rate becomes higher than a flow
velocity of the cooling gas in a second zone having a higher
cooling rate used as a reference, thereby adjusting the cooling
rate of the first zone to be closer to the cooling rate of the
second zone.
2. The apparatus according to claim 1, wherein the cooling
mechanism comprises a plurality of supply pipes, which respectively
supply the cooling gas to the zones to cool the zones, and a
plurality of valves respectively arranged on the supply pipes to
adjust supply rates of the cooling gas to the zones, and the
controller adjusts opening degrees of the valves to control flow
velocities of the cooling gas in the zones.
3. The apparatus according to claim 2, wherein the supply pipes are
connected to a common blower, which supplies the cooling gas to the
supply pipes.
4. The apparatus according to claim 2, wherein the cooling
mechanism comprises a common exhaust pipe, which exhausts the
cooling gas from all the zones.
5. The apparatus according to claim 2, wherein the cooling
mechanism comprises a plurality of exhaust pipes, which
respectively exhaust the cooling gas from the zones.
6. The apparatus according to claim 1, wherein the cooling
mechanism comprises a supply pipe, which supplies the cooling gas
to the zones to cool the zones, a plurality of exhaust pipes, which
respectively exhaust the cooling gas from the zones, and a
plurality of valves respectively arranged on the exhaust pipes to
adjust exhaust rates of the cooling gas from the zones, and the
controller adjusts opening degrees of the valves to control flow
velocities of the cooling gas in the zones.
7. The apparatus according to claim 6, wherein the exhaust pipes
are connected to a common blower, which exhausts the cooling gas
from the exhaust pipes.
8. The apparatus according to claim 6, wherein the cooling
mechanism comprises a plurality of supply pipes, which respectively
supply the cooling gas to the zones to cool the zones.
9. The apparatus according to claim 1, wherein the zones are
separated from each other by partitions disposed in the heating
space.
10. The apparatus according to claim 1, further comprising an liner
tube disposed between the process chamber and the surrounding
member and surrounding the process chamber, such that the heating
space is formed between the liner tube and surrounding member.
11. The apparatus according to claim 10, wherein the temperature
sensors are disposed between the process chamber and the liner tube
to respectively correspond to the zones.
12. The apparatus according to claim 1, wherein the reference value
is inputted into the controller in advance.
13. The apparatus according to claim 1, wherein the reference value
is calculated by the controller on the basis of temperatures
detected by the temperature sensors when the process chamber is
cooled.
14. The apparatus according to claim 1, wherein the holder holds
the target substrates such that they are stacked one on the other
with a gap therebetween in a vertical direction.
15. The apparatus according to claim 1, further comprising a supply
section, which supplies the process gas into the process chamber
and an exhaust section, which exhausts the process chamber.
16. A heat processing method in the apparatus according to claim 1,
comprising: subjecting the target substrates to a heat process, in
which the target substrates are held by the holder in the process
chamber, and heated by the heater; performing, after the heat
process, a cooling operation to cool the process chamber, in which
the controller controls the cooling mechanism on the basis of
temperatures detected by the temperature sensors, such that a flow
velocity of the cooling gas in a first zone having a lower cooling
rate becomes higher than a flow velocity of the cooling gas in a
second zone having a higher cooling rate used as a reference,
thereby adjusting the cooling rate of the first zone to be closer
to the cooling rate of the second zone.
17. The method according to claim 16, wherein the cooling mechanism
comprises a plurality of supply pipes, which respectively supply
the cooling gas to the zones to cool the zones, and a plurality of
valves respectively arranged on the supply pipes to adjust supply
rates of the cooling gas to the zones, and the controller adjusts
opening degrees of the valves to control flow velocities of the
cooling gas in the zones.
18. The method according to claim 16, wherein the cooling mechanism
comprises a supply pipe, which supplies the cooling gas to the
zones to cool the zones, a plurality of exhaust pipes, which
respectively exhaust the cooling gas from the zones, and a
plurality of valves respectively arranged on the exhaust pipes to
adjust exhaust rates of the cooling gas from the zones, and the
controller adjusts opening degrees of the valves to control flow
velocities of the cooling gas in the zones.
19. A vertical heat-processing apparatus for a semiconductor
process in which a plurality of target substrates are
simultaneously subjected to a heat-process, the apparatus
comprising: a process chamber, which accommodates the target
substrates; a supply section, which supplies the process gas into
the process chamber; an exhaust section, which exhausts the process
chamber; a holder, which holds the target substrates in the process
chamber such that they are stacked one on the other with a gap
therebetween in a vertical direction; a heater disposed around the
process chamber, which heats an interior of the process chamber
through a sidewall of the process chamber; a surrounding member,
which surrounds the process chamber and the heater, and forms a
heating space around the process chamber, the heating space
comprising a plurality of zones juxtaposed in a vertical direction;
a plurality of the temperature sensors, which detect temperatures
respectively representing the zones; a cooling mechanism, which
forms flows of a cooling gas respectively in the zones, and cools
the zones, the cooling mechanism comprising a plurality of supply
pipes, which respectively supply the cooling gas to the zones to
cool the zones, a plurality of valves respectively arranged on the
supply pipes to adjust supply rates of the cooling gas to the
zones, and an exhaust pipe, which exhausts the cooling gas from the
zones; and a controller, which adjusts opening degrees of the
valves on the basis of temperatures detected by the temperature
sensors when the process chamber is cooled, such that a flow
velocity of the cooling gas in a first zone having a lower cooling
rate becomes higher than a flow velocity of the cooling gas in a
second zone having a higher cooling rate used as a reference,
thereby adjusting the cooling rate of the first zone to be closer
to the cooling rate of the second zone.
20. The apparatus according to claim 19, further comprising a liner
tube disposed between the process chamber and the surrounding
member and surrounding the process chamber, such that the heating
space is formed between the liner tube and surrounding member.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No.
2000-252249, filed Aug. 23, 2000, the entire contents of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a heat-processing apparatus
and method for a semiconductor process in which a plurality of
target substrates are subjected to a heat-process simultaneously,
i.e., together at the same time. The term "semiconductor process"
used herein includes various kinds of processes which are performed
to manufacture a semiconductor device or a structure having wiring
layers, electrodes, and the like to be connected to a semiconductor
device, on a target substrate, such as a semiconductor wafer or an
LCD substrate, by forming semiconductor layers, insulating layers,
and conductive layers in predetermined patterns on the target
substrate.
[0004] 2. Description of the Related Art
[0005] In the semiconductor process, a vertical heat-processing
apparatus is known as a batch type processing apparatus that
applies heat processes, such as oxidation, diffusion, annealing,
and CVD, to a number of semiconductor wafers together at the same
time. The vertical heat-processing apparatus is used such that a
number of wafers are arrayed and held with a gap therebetween in a
vertical direction in a holder called a wafer boat, and then the
holder is loaded into a process chamber of a vertical type. Then,
the wafers are subjected to a heat process while they are heated by
a heating mechanism disposed around the process chamber.
[0006] The heating mechanism includes a surrounding member formed
of a cylindrical heat-insulating body, which forms a heating space
around the process chamber. A resistance heating wire (heater) is
disposed on the inner surface of the surrounding member.
Preferably, the heating space comprises a plurality of zones
arrayed in a vertical direction, and the heater comprises a
plurality of heater segments corresponding to the zones. The heater
segments can be controlled independently of each other, so that a
heat process is performed uniformly over all the zones.
[0007] The heating mechanism is arranged to perform a cooling
operation by natural cooling or forcible cooling, which is
performed by gas cooling or liquid cooling. As shown in FIG. 5,
when the heating mechanism is cooled, the cooling rates of the
zones tend to be uneven due to heat discharge and the like.
Generally, the cooling rates of the lower and upper zones of the
heating space are higher than that of the middle zone. Such
unevenness in the cooling rate makes the thermal budgets of wafers
in one lot different from each other.
[0008] The cooling rate of the heating space is set when the
heat-processing apparatus is first installed, using a method so as
to adjust the rate of a zone, which tends to have a higher rate, to
be closer to the rate of a zone, which tends to have a lower rate.
In an apparatus of the natural cooling type, the apparatus is set
such that, for example, the heater segments of the lower and upper
zones are supplied with a voltage to decrease their cooling rates
down to a value as low as the middle zone. In this case, the heat
applied to the lower zone warms the middle zone due to convection,
radiation, and conduction of the heat, resulting in a decrease in
the cooling rate as a whole.
[0009] On the other hand, when an apparatus of the forcible cooling
type is installed, supply rates of a cooling gas to the zones are
adjusted in order to set the cooling rate of the heating space such
that the cooling rate of the middle zone becomes almost the same as
those of the lower and upper zones. In this case, it is necessary
to perform a troublesome operation of repeatedly adjusting manual
valves on air supply pipes while confirming the cooling rates of
the zones.
BRIEF SUMMARY OF THE INVENTION
[0010] An object of the present invention is to provide a
heat-processing apparatus and method for a semi-conductor process,
which prevent the cooling rates of the zones of a heating space
from differing from each other, and increase the cooling rate of
the heating space as a whole.
[0011] Another object of the present invention is to provide a
heat-processing apparatus and method for a semiconductor process,
which does not entail the troublesome operation for setting the
cooling rate of a heating space when the apparatus is
installed.
[0012] According to a first aspect of the present invention, there
is provided a heat-processing apparatus for a semiconductor process
in which a plurality of target substrates are simultaneously
subjected to a heat-process, the apparatus comprising:
[0013] a process chamber, which accommodates the target
substrates;
[0014] a holder, which holds the target substrates with a gap
therebetween in the process chamber;
[0015] a heater disposed around the process chamber, which heats an
interior of the process chamber through a sidewall of the process
chamber;
[0016] a surrounding member, which surrounds the process chamber
and the heater, and forms a heating space around the process
chamber, the heating space comprising a plurality of zones
juxtaposed in a direction in which the target substrates are
arrayed;
[0017] a plurality of the temperature sensors, which detect
temperatures respectively representing the zones;
[0018] a cooling mechanism, which forms flows of a cooling gas
respectively in the zones, and cools the zones; and
[0019] a controller, which controls the cooling mechanism on the
basis of temperatures detected by the temperature sensors when the
process chamber is cooled, such that a flow velocity of the cooling
gas in a first zone having a lower cooling rate becomes higher than
a flow velocity of the cooling gas in a second zone having a higher
cooling rate used as a reference, thereby adjusting the cooling
rate of the first zone to be closer to the cooling rate of the
second zone.
[0020] According to a second aspect of the present invention, there
is provided a heat processing method in the apparatus according to
the first aspect, comprising:
[0021] subjecting the target substrates to a heat process, in which
the target substrates are held by the holder in the process
chamber, and heated by the heater;
[0022] performing, after the heat process, a cooling operation to
cool the process chamber, in which the controller controls the
cooling mechanism on the basis of temperatures detected by the
temperature sensors, such that a flow velocity of the cooling gas
in a first zone having a lower cooling rate becomes higher than a
flow velocity of the cooling gas in a second zone having a higher
cooling rate used as a reference, thereby adjusting the cooling
rate of the first zone to be closer to the cooling rate of the
second zone.
[0023] According to a third aspect of the present invention, there
is provided a vertical heat-processing apparatus for a
semiconductor process in which a plurality of target substrates are
simultaneously subjected to a heat-process, the apparatus
comprising:
[0024] a process chamber, which accommodates the target
substrates;
[0025] a supply section, which supplies the process gas into the
process chamber;
[0026] an exhaust section, which exhausts the process chamber;
[0027] a holder, which holds the target substrates in the process
chamber such that they are stacked one on the other with a gap
therebetween in a vertical direction;
[0028] a heater disposed around the process chamber, which heats an
interior of the process chamber through a sidewall of the process
chamber;
[0029] a surrounding member, which surrounds the process chamber
and the heater, and forms a heating space around the process
chamber, the heating space comprising a plurality of zones
juxtaposed in a vertical direction;
[0030] a plurality of the temperature sensors, which detect
temperatures respectively representing the zones;
[0031] a cooling mechanism, which forms flows of a cooling gas
respectively in the zones, and cools the zones, the cooling
mechanism comprising a plurality of supply pipes, which
respectively supply the cooling gas to the zones to cool the zones,
a plurality of valves respectively arranged on the supply pipes to
adjust supply rates of the cooling gas to the zones, and an exhaust
pipe, which exhausts the cooling gas from the zones; and
[0032] a controller, which adjusts opening degrees of the valves on
the basis of temperatures detected by the temperature sensors when
the process chamber is cooled, such that a flow velocity of the
cooling gas in a first zone having a lower cooling rate becomes
higher than a flow velocity of the cooling gas in a second zone
having a higher cooling rate used as a reference, thereby adjusting
the cooling rate of the first zone to be closer to the cooling rate
of the second zone.
[0033] Additional objects and advantages of the invention will be
set forth in the description which follows, and in part will be
obvious from the description, or may be learned by practice of the
invention. The objects and advantages of the invention may be
realized and obtained by means of the instrumentalities and
combinations particularly pointed out hereinafter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0034] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate embodiments of
the invention, and together with the general description given
above and the detailed description of the embodiments given below,
serve to explain the principles of the invention.
[0035] FIG. 1 is a structural view schematically showing a vertical
heat-processing apparatus for processing semiconductor wafers
according to an embodiment of the present invention;
[0036] FIG. 2 is a structural view schematically showing a vertical
heat-processing apparatus for processing semiconductor wafers
according to another embodiment of the present invention;
[0037] FIG. 3 is a structural view schematically showing a vertical
heat-processing apparatus for processing semiconductor wafers
according to still another embodiment of the present invention;
[0038] FIG. 4 is a structural view schematically showing a vertical
heat-processing apparatus for processing semiconductor wafers
according to still another embodiment of the present invention;
and
[0039] FIG. 5 is a graph showing the cooling rate of a heating
space in a vertical heat-processing apparatus.
DETAILED DESCRIPTION OF THE INVENTION
[0040] Embodiments of the present invention will be described
hereinafter with reference to the accompanying drawings. In the
following description, the constituent elements having
substantially the same function and arrangement are denoted by the
same reference numerals, and a repetitive description will be made
only when necessary.
[0041] FIG. 1 is a structural view schematically showing a vertical
heat-processing apparatus for processing semiconductor wafers
according to an embodiment of the present invention. The vertical
heat-processing apparatus includes a vertical furnace 1, which
functions as, e.g., a high-temperature furnace or diffusion
furnace. The furnace 1 has a process chamber or process tube 3, and
a cylindrical heating mechanism 4 with a liner tube
(temperature-unifying tube) 5 interposed between the heating
mechanism 4 and the process tube 3. A holder, such as a boat 2 made
of quartz, is placed in the process tube 3. The boat 2 holds a
number of, e.g., about 150, target substrates, i.e., semiconductor
wafers W, such that they are stacked one on the other with a gap
therebetween in a vertical direction. The heating mechanism 4 is
arranged to surround the process tube 3, and to heat the interior
of the process tube 3 through the sidewall of the tube 3 to a
predetermined temperature of, e.g., from about 600 to 1,200.degree.
C.
[0042] The process tube 3 is made of a material, such as quartz,
which is heat-resistant and corrosion-resistant, and has a
cylindrical shape vertically elongated, with a closed top and an
open bottom. The lower portion of the process tube 3 is connected
to a gas supply line Gi for supplying a process gas or an inactive
gas, and an exhaust line Go for exhausting the interior of the
process tube 3. The gas supply line Gi is connected to a process
gas supply section PS. The exhaust line Go is connected to a vacuum
exhaust section VE including a vacuum pump, a pressure valve, and
so forth. The process tube 3 may have a double-tube structure
formed of inner and outer tubes.
[0043] The bottom end of the process tube 3 is supported by a base
plate 6 through an attachment (not shown) disposed below the base
plate 6. The base plate 6 is made of, e.g., stainless steel, and
disposed horizontally in the casing of the vertical heat-processing
apparatus. The base plate 6 is provided with an opening 7 formed
therein, through which the process tube 3 is inserted in a vertical
direction. A heat-insulating body 8 is attached to the opening 7
around the process tube 3 to prevent the opening 7 from allowing
heat to be discharged.
[0044] A lid 9 made of, e.g., stainless steel is disposed below the
process tube 3, to be movable up and down by an elevating mechanism
(not shown) so as to close and open the bottom opening of the
process tube 3. A boat 2 is mounted on the lid 9 via an insulating
cylinder 10. The elevating mechanism is used to transfer the boat 2
into and out of the process tube 3 and to open and close the lid 9.
The lid 9 is provided with a rotational mechanism (not shown) to
rotate the boat 2 along with the insulating cylinder 10, so that
the semiconductor wafers W are processed with a high planar
uniformity.
[0045] The heating mechanism 4 includes a surrounding member 11,
which is formed of a cylindrical heat-insulating body and forms a
heating space HS around the process tube 3. A heater 12 comprising
resistance heating wires is disposed on the inner face of the
surrounding member 11 such that the wires meanderingly extend in
the angular direction of the member 11 or spirally extend in the
longitudinal direction of the member 11. The heating space HS
consists of a plurality of zones, e.g., five zones Z1 to Z5,
arrayed in a vertical direction, while the heater 12 consists of a
plurality of heater segments respectively corresponding to the
zones. The heater segments can be controlled independently of each
other, so that a uniform heat process is performed over all the
zones. The surrounding member 11 is covered with a water-cooling
jacket (not shown). The heating mechanism 4 is placed on the base
plate 6.
[0046] The liner tube 5 is made of, e.g., silicon carbide (SiC).
The heating space HS is formed as a space substantially closed
between the surrounding member 11 and the liner tube 5. The liner
tube 5 improves uniformity in the heating temperature to the wafers
W placed in the process tube 3. The liner tube 5 also prevents the
wafers W from being contaminated with metals discharged from the
resistance heating wires and the like of the heating mechanism 4.
The liner tube 5 has a cylindrical shape vertically elongated, with
a closed top and an open bottom. The liner tube 5 surrounds the
process tube 3 and is placed on the heat-insulating body 8 of the
base plate 6. The liner tube 5 may be omitted, such that a heating
space HS is formed between the surrounding member 11 and the
process tube (process chamber) 3.
[0047] The heating mechanism 4 is provided with a cooling mechanism
13, which forms a flow of cooling gas in each of the zones Z1 to Z5
of the heating space HS to cool the zones Z1 to Z5. The cooling
mechanism 13 includes supply pipes 15, which respectively supply a
cooling gas, such as air (clean air) to the zones Z1 to Z5 to cool
them. The supply pipes 15 are connected to a common blower (supply
blower) 18 for supplying the cooling gas. The distal ends of the
supply pipes 15 penetrate the sidewall of the surrounding member 11
and come into the respective zones Z1 to Z5 of the heating space
HS. The cooling mechanism 13 also includes a common exhaust pipe 20
connected to a blower (exhaust blower) 19 for exhausting the
cooling gas from the heating space HS.
[0048] The supply pipes 15 are respectively provided with valves 16
to adjust supply rates of the cooling gas into the zones Z1 to Z5.
Each of the valves 16 is formed of, e.g., a valve of the type
driven by an actuator, whose opening degree is controlled by a
controller 17. Temperature sensors 14 are arranged to detect
temperatures respectively representing the zones Z1 to Z5 of the
heating space HS. The temperature sensors 14 consist of, e.g.,
thermocouples, disposed between the process tube 3 and the liner
tube 5 to respectively correspond to the zones Z1 to Z5. Each of
the temperature sensors 14 may be inserted in and covered with a
protection tube made of quartz.
[0049] The controller 17 is set to recognize as a reference value
the cooling rate of a zone that has the highest cooling rate, when
it controls the flow of the cooling gas. The reference value may be
a fixed value, which has been obtained by experiment and the like
in advance, and inputted into the controller 17. Instead, the
reference value may be a non-fixed value, which is calculated at
each time by the controller 17 on the basis of temperatures
detected by the temperature sensors 14 during a cooling
operation.
[0050] The controller 17 controls the opening degrees of the valves
16 of the supply pipes 15, on the basis of the temperatures
corresponding to the zones Z1 to Z5, which are detected by the
temperature sensors 14, so that the cooling rate of the heating
space HS as a whole is adjusted to be the reference value. More
specifically, the controller 17 controls, on the basis of the
detected temperatures, the supply rate of cooling air to a zone
having a lower cooling rate, such as the middle zones Z3, to be
higher than that to a zone having the highest cooling rate, such as
the lower zones Z5, so that the lower cooling rate is adjusted to
be closer to, i.e., approximate, the highest cooling rate. In other
words, the controller 17 controls the cooling mechanism 13 such
that the flow velocity of the cooling gas in a first zone having a
lower cooling rate becomes higher than the flow velocity of the
cooling gas in a second zone having a higher cooling rate, thereby
adjusting the cooling rate of the first zone to be closer to the
cooling rate of the second zone.
[0051] An explanation will be given of a heat processing method in
the vertical heat-processing apparatus shown in FIG. 1.
[0052] First, the boat 2, which has been loaded with wafers W, is
placed on the insulating cylinder 10 supported by the lid 9 at a
loading area below the heating mechanism 4. Then, the lid 9 is
moved up by the elevating mechanism, so that the boat 2 is inserted
into the process tube 3 through the bottom opening, which is then
airtightly closed by the lid 9. Then, while the process tube 3 is
exhausted, the wafers W on the boat 2 are heated up to a
predetermined process temperature by the heating mechanism 4. Then,
while the process tube 3 is exhausted, a predetermined process gas
is supplied into the process tube 3 to subject the wafers W to a
predetermined heat process, such as a diffusion process.
[0053] After the heat process ends, the heater 12 of the heating
mechanism 4 is first turned off. Then, the blower 18 is operated to
supply air used as a cooling gas through the supply pipes 15 into
the heating space HS, so as to forcibly cool the interior of the
heating space HS. At this time, the temperature sensors 14 detect
temperatures representing the zones Z1 to Z5. The controller 17
controls, on the basis of the detected temperatures, the supply
rate of cooling air to a zone having a lower cooling rate, such as
the middle zones Z3, to be higher than that to a zone having the
highest cooling rate, such as the lower zones Z5, so that the lower
cooling rate is adjusted to be closer to the highest cooling rate.
As a result, it is possible to prevent the cooling rates of the
zones Z1 to Z5 from being uneven, and also to cause the cooling
rates to be higher as a whole. Furthermore, as this method allows a
flexible control oriented toward a decrease in temperature, the
thermodynamics of the furnace 1 is improved.
[0054] Accordingly, the vertical heat-processing apparatus shown in
FIG. 1 can automatically control the cooling rates of the zones Z1
to Z5 to be uniform under the control of the controller 17. In
addition, the cooling rate of the heating space HS can be higher as
a whole to improve the thermodynamics.
[0055] FIG. 2 is a structural view schematically showing a vertical
heat-processing apparatus for processing semiconductor wafers
according to another embodiment of the present invention. This
vertical heat-processing apparatus includes a heating space HS,
which comprises zones Z1 to Z5 separated from each other by
partitions 21 made of, e.g., quartz. The zones Z1 to Z5 are
respectively provided with exhaust pipes 22 connected thereto, for
exhausting a cooling gas independently of each other.
[0056] The vertical heat-processing apparatus shown in FIG. 2 can
provide the same effect as the vertical heat-processing apparatus
shown in FIG. 1. Furthermore, since the heating space HS is divided
into the zones Z1 to Z5 by the partitions 21, the zones Z1 to Z5
can be cooled independently of each other. As in this embodiment,
where the heating space HS is partitioned into the zones Z1 to Z5,
it is possible to form a flow of the cooling gas only in a zone
having a lower cooling rate so as to solve a temperature difference
between the zones, in the case of not only the forcible cooling,
but also natural cooling.
[0057] FIG. 3 is a structural view schematically showing a vertical
heat-processing apparatus for processing semiconductor wafers
according to still another embodiment of the present invention.
This vertical heat-processing apparatus includes a heating space
HS, which comprises zones Z1 to Z5 separated from each other by
partitions 21 made of, e.g., quartz. The zones Z1 to Z5 are
respectively provided with supply pipes 27 connected thereto, for
supplying a cooling gas independently of each other, and exhaust
pipes 23 connected thereto, for exhausting the cooling gas
independently of each other. The exhaust pipes 23 are connected to
a common blower (exhaust blower) 25.
[0058] The exhaust pipes 23 are respectively provided with valves
24 to adjust exhaust rates of the cooling gas from the zones Z1 to
Z5. Each of the valves 24 is formed of, e.g., a valve of the type
driven by an actuator, whose opening degree is controlled by a
controller 17. Temperature sensors 14 are arranged to detect
temperatures respectively representing the zones Z1 to Z5 of the
heating space HS.
[0059] The controller 17 controls the opening degrees of the valves
24 of the exhaust pipes 23, on the basis of the temperatures
corresponding to the zones Z1 to Z5, which are detected by the
temperature sensors 14, so that the cooling rate of the heating
space HS as a whole is adjusted to be a reference value
corresponding to the highest cooling rate. More specifically, the
controller 17 controls, on the basis of the detected temperatures,
the exhaust rate of cooling air from a zone having a lower cooling
rate, such as the middle zones Z3, to be higher than that from a
zone having the highest cooling rate, such as the lower zones Z5,
so that the lower cooling rate is adjusted to be closer to, i.e.,
approximate, the highest cooling rate. In other words, the
controller 17 controls the cooling mechanism 13 such that the flow
velocity of the cooling gas in a first zone having a lower cooling
rate becomes higher than the flow velocity of the cooling gas in a
second zone having a higher cooling rate, thereby adjusting the
cooling rate of the first zone to be closer to the cooling rate of
the second zone.
[0060] Accordingly, the vertical heat-processing apparatus shown in
FIG. 3 can automatically control the cooling rates of the zones Z1
to Z5 to be uniform under the control of the controller 17. In
addition, the cooling rate of the heating space HS can be higher as
a whole to improve the thermodynamics.
[0061] FIG. 4 is a structural view schematically showing a vertical
heat-processing apparatus for processing semiconductor wafers
according to still another embodiment of the present invention.
This vertical heat-processing apparatus has a structure combining
the features shown in FIG. 2 and the features shown in FIG. 3 with
each other. More specifically, the vertical heat-processing
apparatus includes a heating space HS, which comprises zones Z1 to
Z5 separated from each other by partitions 21 made of, e.g.,
quartz. The zones Z1 to Z5 are respectively provided with supply
pipes 15 connected thereto, for supplying a cooling gas
independently of each other, and exhaust pipes 23 connected
thereto, for exhausting the cooling gas independently of each
other. The supply pipes 15 are connected to a common blower (supply
blower) 18, and the exhaust pipes 23 are connected to a common
blower (exhaust blower) 25.
[0062] The supply pipes 15 are respectively provided with valves 16
to adjust supply rates of the cooling gas into the zones Z1 to Z5.
The exhaust pipes 23 are respectively provided with valves 24 to
adjust exhaust rates of the cooling gas from the zones Z1 to Z5.
The controller 17 controls the opening degrees of the valves 16 of
the supply pipes 15 and the opening degrees of the valves 24 of the
exhaust pipes 23, on the basis of the temperatures corresponding to
the zones Z1 to Z5, which are detected by the temperature sensors
14, so that the cooling rate of the heating space HS as a whole is
adjusted to be a reference value corresponding to the highest
cooling rate.
[0063] Accordingly, the vertical heat-processing apparatus shown in
FIG. 4 can more reliably achieve the advantages described with
reference to the vertical heat-processing apparatuses shown in
FIGS. 1 to 3, i.e., to prevent the cooling rates of the zones Z1 to
Z5 from being uneven, and to control the cooling rate of the
heating space HS to be higher as a whole.
[0064] In all the embodiments, the liner tube 5 may be omitted,
wherein the heating space HS is formed between the surrounding
member 11 and the process tube (process chamber) 3. A manifold made
of a metal, such as stainless steel, and provided with a gas supply
line and an exhaust line may be airtightly attached to the bottom
of the process tube 3.
[0065] The present invention may be applied to a low-temperature
furnace, such as a CVD furnace. The present invention may also be
applied to a horizontal heat-processing apparatus in place of the
vertical heat-processing apparatus. Furthermore, the present
invention may be applied to a target substrate other than a
semiconductor wafer, such as an LCD substrate, or a glass
substrate.
[0066] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
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