U.S. patent application number 11/987891 was filed with the patent office on 2008-07-24 for substrate processing apparatus, method of manufacturing semiconductor device, and reaction vessel.
This patent application is currently assigned to HITACHI KOKUSAI ELECTRIC INC.. Invention is credited to Yukinori Aburatani, Seiyo Nakashima.
Application Number | 20080173238 11/987891 |
Document ID | / |
Family ID | 39640033 |
Filed Date | 2008-07-24 |
United States Patent
Application |
20080173238 |
Kind Code |
A1 |
Nakashima; Seiyo ; et
al. |
July 24, 2008 |
Substrate processing apparatus, method of manufacturing
semiconductor device, and reaction vessel
Abstract
A substrate processing apparatus that affords improved
uniformity to in-plane wafer and interwafer film thickness of a
large number of wafers on which a film is simultaneously formed,
having: a reaction tube having in an interior thereof a processing
chamber in which a plurality of substrates disposed in a direction
perpendicular to a substrate processing surface can be processed;
and a heating device provided to surround an outer circumference of
the reaction tube, a gas inlet tube being provided on a side face
of the reaction tube in a region for processing a substrate inside
the reaction tube, so as to reach at least an outside of the
heating device; and a gas spouting port being disposed in this gas
inlet tube in a slit form so as to straddle at least a plurality of
the substrates in a direction perpendicular to the substrate
processing surface, for spouting gas from the gas inlet tube into
the processing chamber.
Inventors: |
Nakashima; Seiyo;
(Toyama-shi, JP) ; Aburatani; Yukinori;
(Toyama-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 320850
ALEXANDRIA
VA
22320-4850
US
|
Assignee: |
HITACHI KOKUSAI ELECTRIC
INC.
TOKYO
JP
|
Family ID: |
39640033 |
Appl. No.: |
11/987891 |
Filed: |
December 5, 2007 |
Current U.S.
Class: |
118/723R ;
118/715; 257/E21.159; 438/758 |
Current CPC
Class: |
C23C 16/345 20130101;
C23C 16/4584 20130101; C23C 16/4412 20130101; C23C 16/44 20130101;
C23C 16/45519 20130101; C23C 16/45502 20130101 |
Class at
Publication: |
118/723.R ;
438/758; 118/715; 257/E21.159 |
International
Class: |
C23C 16/513 20060101
C23C016/513; H01L 21/283 20060101 H01L021/283; C23C 16/44 20060101
C23C016/44 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 12, 2006 |
JP |
2006-334990 |
Dec 27, 2006 |
JP |
2006-350882 |
Nov 22, 2007 |
JP |
2007-303489 |
Claims
1. A substrate processing apparatus comprising: a reaction tube
having in an interior thereof a processing chamber in which a
plurality of substrates disposed in a direction perpendicular to a
substrate processing surface can be processed; and a heating device
provided to surround an outer circumference of the reaction tube, a
gas inlet tube being provided on a side face of said reaction tube
in a region for processing a substrate inside said reaction tube,
so as to reach at least an outside of said heating device, and a
gas spouting port being disposed in the gas inlet tube in a slit
form so as to straddle at least a plurality of the substrates in a
direction perpendicular to said substrate processing surface, for
spouting gas from said gas inlet tube into said processing
chamber.
2. The substrate processing apparatus as claimed in claim 1,
wherein said gas inlet tube comprises a plurality of gas
introduction partition portions partitioned in a direction
perpendicular to a processing surface of said substrates, and said
gas spouting port is formed in each of said gas introduction
partition portions.
3. The substrate processing apparatus as claimed in claim 2,
wherein said gas spouting port is formed one for each of said gas
introduction partition portions.
4. The substrate processing apparatus as claimed in claim 2,
wherein an opening area of said gas spouting port is identical to a
cross-sectional area of said gas introduction partition portion in
a direction perpendicular to said substrate processing surface.
5. The substrate processing device as claimed in claim 1, wherein
said gas inlet tube is formed so that a distance from at least said
gas spouting port to an upstream tip-end portion of the gas inlet
tube is greater than a distance between two ends of said gas
spouting port in a circumferential direction of the substrates.
6. The substrate processing apparatus as claimed in claim 1,
wherein said gas inlet tube is formed along an entire side along
said substrate processing region.
7. The substrate processing apparatus as claimed in claim 1,
further comprising: a gas exhaust tube being provided on a side
face of said reaction tube in a region for processing a substrate
inside said reaction tube so as to reach at least an outside of
said heating device; and a gas exhaust port being disposed in the
gas exhaust tube in a slit form so as to straddle at least a
plurality of the substrates in a direction perpendicular to said
substrate processing surface, for exhausting gas into said gas
exhaust tube from said processing chamber.
8. The substrate processing apparatus as claimed in claim 7,
wherein said gas exhaust tube comprises a plurality of gas exhaust
partition portions partitioned in a direction perpendicular to a
processing surface of said substrates, and said gas exhaust port is
formed in each of said gas exhaust partition portions.
9. The substrate processing apparatus as claimed in claim 2,
wherein a process gas supply portion and a first inert gas supply
portion are connected to an upstream side of said gas introduction
partition portions, the substrate processing apparatus further
comprising a gas supply control portion for, when processing the
substrates in said reaction tube, supplying a process gas from the
process gas supply portion when the substrates are disposed in
positions opposing the gas introduction partition portions, and
supplying an inert gas from the inert gas supply portion when no
substrate is disposed in positions opposing the gas introduction
partition portions.
10. The substrate processing apparatus as claimed in claim 1,
further comprising a plasma generating device constituted from
electrodes disposed outside the processing chamber, with said gas
inlet tube placed between these electrodes, for creating plasma of
a gas in said gas inlet tube.
11. The substrate processing apparatus as claimed in claim 1,
further comprising a second inert gas supply portion for supplying
an inert gas from above said reaction tube into the reaction
tube.
12. The substrate processing apparatus as claimed in claim 11,
further comprising a third inert gas supply portion for supplying
an inert gas from below said reaction tube into the reaction
tube.
13. The substrate processing apparatus as claimed in claim 1,
further comprising a gas interrupting portion above said reaction
tube.
14. The substrate processing apparatus as claimed in claim 13,
wherein said gas interrupting portion is provided in an inner wall
of said reaction tube.
15. The substrate processing apparatus as claimed in claim 1,
comprising protruding portions provided to protrude inward from an
inner wall surface of said reaction tube at, at least, an upper and
a lower end of said gas inlet tube and said gas exhaust tube.
16. The substrate processing apparatus as claimed in claim 15,
comprising notched portions provided in the same positions as in
said protruding portions in a circumferential direction with
respect to a processing surface of said substrates.
17. The substrate processing apparatus as claimed in claim 16,
wherein a temperature detector for detecting a temperature within a
processing chamber is housed in said notched portions of said
protruding portions.
18. The substrate processing apparatus as claimed in claim 1,
wherein a width of said spouting port in a direction horizontal to
said substrate surface is 1/2 or less of a diameter of said
substrates.
19. A method of manufacturing a semiconductor device for processing
in use of the substrate processing apparatus as claimed in claim 1,
the method comprising the steps of: conveying substrates into said
reaction tube; processing the substrates by introducing a gas from
said gas spouting port across the substrates within said reaction
tube while maintaining a gas flow velocity in said gas inlet tube,
and heating said reaction tube by means of said heating device; and
conveying the substrates out of said reaction tube.
20. A reaction vessel in a cylindrical shape having in an interior
thereof a processing chamber in which a plurality of substrates
disposed in a direction perpendicular to a substrate processing
surface can be processed, comprising: a gas inlet tube and a gas
exhaust tube being provided on a side face of said reaction tube in
a region for processing a substrate inside said reaction tube, said
gas inlet tube and said gas exhaust tube extending in a direction
perpendicular to said side face of said reaction tube, and a gas
spouting port being disposed in at least said gas inlet tube in a
form so as to straddle at least a plurality of the substrates in a
direction perpendicular to said substrate processing surface, for
spouting gas from said gas inlet tube into said processing chamber.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a substrate processing
apparatus and method of manufacturing a semiconductor device, and
more particularly to the effective utilization thereof in a
substrate processing technology in which, in a process for
manufacturing a semiconductor device, a thermochemical reaction is
utilized to administer a desired processing such as the fabrication
of an oxide film or metal film on a substrate such as a
semiconductor wafer (hereinafter also referred to as a wafer).
[0003] 2. Description of the Related Art
[0004] In a process for manufacturing a semiconductor device,
vertical-type semiconductor manufacturing apparatuses are sometimes
employed as substrate processing apparatuses for fabricating an
oxide film or metal film on a wafer.
[0005] Conventional vertical-type semiconductor manufacturing
apparatuses of this type comprise a processing furnace configured
from a reaction vessel and a heater in which a gas is introduced
into the heated reaction vessel while being exhausted therefrom.
Various methods are employed for introducing the gas into the
reaction vessel.
[0006] For example, in the vertical-type semiconductor
manufacturing apparatus shown in FIG. 18, a cylindrical reaction
tube 2 serving as an outer tube configured from a heat-resistant
material such as quartz glass is disposed roughly perpendicularly
on a manifold 5 constituted from, for example, a metal material
such as stainless steel. A cylindrical tube 3 serving as an inner
tube is provided on the inner side of the reaction tube 2. A port 4
for holding a plurality of wafers W is provided in the inner side
of the cylindrical tube 3. A gas introduction inlet 6 and an
exhaust outlet 7 are provided in the manifold 5. In addition, a
heater 1 is provided to surround the outer circumference of the
reaction tube 2, the interior of the reaction tube 2 being able to
be thermally processed thereby to a predetermined temperature. The
reaction vessel is constituted from the aforementioned reaction
tube 2, cylindrical tube 3 and manifold 5.
[0007] In a process of film formation, a predetermined film
formation gas is introduced as indicated by the arrows through the
introduction inlet 6 provided in the manifold 5 into the interior
of the reaction tube 2 maintained to a predetermined pressure. The
gas introduced from below the reaction tube 2 into the interior of
the reaction tube is exhausted above the reaction tube 2 by way of
a wafer processing space 10 and, after passing through a
cylindrical space formed between the reaction tube 2 and the
cylindrical tube 3, is exhausted from the exhaust outlet 7 provided
in the manifold 5. By provision of the introduction inlet 6 in the
manifold 5 in the manufacturing apparatus shown in FIG. 18 in this
way, a film formation gas is introduced from below the wafer
processing space 10 and exhausted thereabove.
[0008] In addition, while the vertical-type semiconductor
manufacturing apparatus shown in FIG. 19 has the same basic
configuration as the apparatus shown in FIG. 18, the following
points of difference exist therebetween. For the purpose of
extending the introduction inlet 6 to the wafer processing space
10, a plurality of gas nozzles 16 of different length are provided
upright from the manifold 5 into the wafer processing space 10. As
shown by the arrows, a film formation gas is introduced through
apex portions of the gas nozzles 16 located to the side of the
wafers W, and exhausted therebelow through the gas exhaust outlet 7
(for example, see Japanese Unexamined Patent Application
Publication No. 2000-68214).
[0009] In addition, while the vertical-type semiconductor apparatus
shown in FIG. 20 has the same basic configuration as the apparatus
shown in FIG. 18, the following points of different exist
therebetween. For the purpose of extending the introduction inlet 6
to the wafer processing space 10, a gas nozzle 26 is provided
upright from the manifold 5. A large number of holes opposing the
plurality of wafers W are provided in the gas nozzle 26, a film
formation gas being introduced from the side of the wafers W and
exhausted therebelow through the gas exhaust outlet 7 as shown by
the arrows.
[0010] If the size of the diameters of the large number of holes
provided in the gas nozzle 26 are the same, the flow rate of the
film formation gas through these holes cannot be made uniform due
to the gas pressure difference between holes provided in the lower
part (gas upstream side) and the holes provided in the upper part
(gas downstream side). Thereupon, in order to ensure uniformity of
the flow rate of the film formation gas using a gas nozzle of this
kind, the size of the diameter of the holes between the lower and
upper parts is made different.
[0011] In addition, the reaction vessel of the vertical-type
semiconductor manufacturing apparatus shown in FIG. 21 is a single
tube configuration constituted from the reaction tube 2 alone, and
does not comprise either a cylindrical tube or a manifold. A gas
nozzle 36 that communicates with the introduction inlet 6 is
provided along the outer side wall of the reaction tube 2 from
below the reaction tube 2 to a ceiling portion of the reaction tube
2, a film formation gas being supplied from above the wafer
processing space 10 and exhausted therebelow through the gas
exhaust outlet 7 as shown by the arrows.
[0012] The following various problems are inherent to the
conventional vertical-type semiconductor manufacturing apparatuses
as described above.
[0013] For example, there is a problem inherent to the apparatus
shown in FIG. 18 in that, because the film formation gas is
introduced from below and exhausted thereabove, the film formation
gas is less likely to flow to the center of the wafers W and,
accordingly, differences in film thickness between the center and
outer circumferential portions of the wafers are generated and the
wafer in-plane film thickness uniformity is affected. There is a
further problem inherent thereto in that, comparing the wafers W of
positions in the lower part and the upper part of the wafer
processing space 10, film formation differences between wafers
located in the upper part and those in the lower part are generated
due to consumption of the film formation gas occurring at the lower
part and, accordingly, the wafers of the lower part are formed
thicker and the wafer in-plane film thickness uniformity is
affected.
[0014] In addition, in the apparatus shown in FIG. 19, even though
the in-plane and interwafer film thickness uniformity are by and
large satisfactory, the necessity for a plurality of gas nozzles of
differing length translates to poor maintenance characteristics. In
addition, because the gas nozzles 16 are provided in the wafer
processing space 10, reaction product attaches to and accumulates
thereon. This attachment and accumulation of a reaction product is
particularly marked in the process for the formation of, for
example, a Si.sub.3N.sub.4 film. There is an additional problem in
that, if the film formation conditions are altered, in most
instances the changes in the film formation conditions cannot be
accommodated without altering length and the number of the gas
nozzles 16, while not altering the type of gas nozzles 16 restricts
the conditions at which a film is able to be formed.
[0015] There is a problem inherent to the apparatus shown in FIG.
20 in that, because the gas nozzle 26 is provided in the wafer
processing space 10, reaction product attaches to and accumulates
thereon. More specifically, this problem resides in the necessity
for a maintenance operation to be performed on the holes of the gas
nozzle 26 when a reaction product attaches to and accumulates
thereon. For example, when the attachment and accumulation of a
reaction product is likely to occur such as in the process for the
formation of a Si.sub.3N.sub.4 film, the holes block quickly and a
maintenance operation on these holes must be frequently performed.
There is an additional problem in that, if the film formation
conditions are altered, the gas nozzle type must be altered in
order to alter the holes, and not altering the type of gas nozzle
restricts the conditions in which film formation is possible. A
further problem resides in the increase in the size of the holes of
the gas nozzle 26 caused by an etching processing performed to
clean the reaction product and, accordingly, the need for the gas
nozzle to be replaced to control the hole size.
[0016] In addition, there is a problem inherent to the apparatus
shown in FIG. 21 in that the in-plane and interwafer film thickness
uniformity are affected in the same way as described for the
apparatus of FIG. 18.
A problem inherent to conventional substrate processing apparatuses
in which a gas is introduced from below a reaction tube and
exhausted thereabove as described above resides in the gas not
being able to pass properly across the substrates and, in turn, the
in-plane and intersubstrate film thickness uniformity being unable
to be improved. An additional problem inherent to conventional
substrate processing apparatuses in which a gas is supplied via a
gas nozzle from the side of a reaction tube and exhausted
thereabove resides in the in-plane and interwafer film thickness
uniformity being unable to be improved without the gas inlet tube
being frequently maintained and replaced.
[0017] With the problems of the conventional art described above in
mind, it is an object of the present invention to provide a
substrate processing apparatus and method of manufacturing a
semiconductor device that, eliminating the need for the gas supply
pipe to be frequently maintained and replaced, affords improved
wafer in-plane and interwafer film thickness uniformity of a
plurality of wafers on which a film is simultaneously formed.
SUMMARY OF THE INVENTION
[0018] A first aspect of the present invention provides a substrate
processing apparatus comprising: a reaction tube having in an
interior thereof a processing chamber in which a plurality of
substrates disposed in a direction perpendicular to a substrate
processing surface can be processed; and a heating device provided
to surround an outer circumference of the reaction tube,
[0019] a gas inlet tube being provided on a side face of the
abovementioned reaction tube in a region for processing a substrate
inside the abovementioned reaction tube, so as to reach at least an
outside of the abovementioned heating device, and
[0020] a gas spouting port being disposed in this above-mentioned
gas inlet tube in a slit form so as to straddle at least a
plurality of the substrates in a direction perpendicular to the
abovementioned substrate processing surface, for spouting gas from
the gas inlet tube into the abovementioned processing chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a schematic side view of a vertical-type
semiconductor manufacturing apparatus of a first embodiment of the
present invention;
[0022] FIG. 2 is a schematic side view of the vertical-type
semiconductor manufacturing apparatus of the first embodiment of
the present invention;
[0023] FIG. 3 is a schematic side view of a gas inlet tube and a
gas exhaust tube of a reaction tube of the first embodiment of the
present invention;
[0024] FIG. 4 is a schematic view of a gas inlet tube and a gas
exhaust tube of a reaction tube of a first modification of the
first embodiment;
[0025] FIG. 5 is a schematic view of a gas inlet tube and a gas
exhaust tube of a reaction tube of a second and a third
modification of the first embodiment;
[0026] FIG. 6 is a schematic plan view of a plasma vertical-type
semiconductor manufacturing apparatus of a fourth modification of
the first embodiment;
[0027] FIG. 7 is a plasma generation circuit diagram of the fourth
modification of the first embodiment;
[0028] FIG. 8 is a schematic side view of a reaction tube upper
part of a fifth modification of the first embodiment;
[0029] FIG. 9 is a schematic side view of a reaction tube upper
part of a sixth modification of the first embodiment;
[0030] FIG. 10 is a schematic side view of a reaction tube upper
part of a seventh modification of the first embodiment;
[0031] FIG. 11 is a schematic side view of means for preventing
film formation gas flowing into the reaction tube upper part of an
eighth modification of the first embodiment;
[0032] FIG. 12 is a schematic side view of means for preventing
film formation gas flowing into the reaction tube upper part of a
ninth modification of the first embodiment;
[0033] FIG. 13 is a schematic side view of means for preventing
film formation gas flowing into the reaction tube upper part of a
tenth modification of the first embodiment;
[0034] FIG. 14 is a schematic side view of means for preventing
film formation gas flowing into the reaction tube upper part of an
eleventh modification of the first embodiment;
[0035] FIG. 15 is a schematic side view of means for preventing
film formation gas flowing into the reaction tube upper part of a
twelfth modification of the first embodiment;
[0036] FIG. 16 is a schematic side view of means for preventing
film formation gas flowing into the reaction tube upper part of a
thirteenth modification of the first embodiment;
[0037] FIG. 17 is a schematic side view of a vertical-type
semiconductor manufacturing apparatus as one embodiment of the
present invention;
[0038] FIG. 18 is a schematic side view of a conventional
vertical-type semiconductor manufacturing apparatus;
[0039] FIG. 19 is a schematic side view of a conventional
vertical-type semiconductor manufacturing apparatus;
[0040] FIG. 20 is a schematic side view of a conventional
vertical-type semiconductor manufacturing apparatus;
[0041] FIG. 21 is a schematic side view of a conventional
vertical-type semiconductor manufacturing apparatus;
[0042] FIG. 22 is a schematic side view of a vertical-type
semiconductor manufacturing apparatus of a second embodiment of the
present invention;
[0043] FIG. 23 is a main part expanded view of the vertical-type
semiconductor manufacturing apparatus of the second embodiment of
the present invention;
[0044] FIG. 24 is a schematic plan view of the vertical-type
semiconductor manufacturing apparatus of the second embodiment of
the present invention;
[0045] FIG. 25 is a main part expanded view of the vertical-type
semiconductor manufacturing apparatus of the second embodiment of
the present invention;
[0046] FIG. 26 is a schematic side view of a port of a first
modification of the second embodiment;
[0047] FIG. 27 is a main part expanded view of a vertical-type
semiconductor manufacturing apparatus of a second modification of
the second embodiment;
[0048] FIG. 28 is a main part expanded view of the vertical-type
semiconductor manufacturing apparatus of a third modification of
the second embodiment;
[0049] FIG. 29 is a schematic side view of a vertical-type
semiconductor manufacturing apparatus of a third embodiment of the
present invention;
[0050] FIG. 30 is a lateral cross-sectional view of a processing
furnace prior to a temperature detector being housed therein of the
third embodiment of the present invention;
[0051] FIG. 31 is a longitudinal cross-sectional view along the
line A-A' of FIG. 30;
[0052] FIG. 32 is a lateral cross-sectional view of a processing
furnace subsequent to a temperature detector being housed therein
of the third embodiment of the present invention;
[0053] FIG. 33 is a simulation model diagram of gas flow velocity
using the slit formed gas spouting port of the embodiments of the
present invention;
[0054] FIG. 34 is an explanatory diagram of the simulation results
for a 300 mm wafer using the slit formed gas spouting port of the
embodiments of the present invention; and
[0055] FIG. 35 is an explanatory diagram of the simulation results
for a 450 mm wafer using the slit formed gas spouting port of the
embodiments of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0056] According to the present invention, the wafer in-plane and
intersubstrate film thickness uniformity of a plurality of
substrates on which a film is formed simultaneously is improved
without need for the gas supply pipe to be frequently maintained
and replaced.
[0057] The embodiments of the present invention will be hereinafter
described with reference to the attached drawings.
<<Processing Furnace>>
[0058] FIG. 1 is a schematic longitudinal cross-sectional view of a
processing furnace 202 of a vertical-type semiconductor
manufacturing apparatus serving as a substrate processing apparatus
ideal for employment in a first embodiment of the present
invention. FIG. 2 is a lateral cross-sectional view of the
processing furnace 202.
<<Outline of Processing Furnace>>
[0059] The vertical-type semiconductor apparatus comprises a
processing furnace 202 constituted from a cylindrical reaction tube
203 and a cylindrical heater 206 serving as a heating device. The
cylindrical reaction tube 203 has in its interior a processing
chamber 201 in which a plurality of wafers 200 disposed in a
direction perpendicular to the processing wafer surface which
constitutes serving as the substrate processing surface are
processable. The cylindrical heater 206 is provided to surround the
outer circumference of the reaction tube 203. A gas inlet tube 230
and a gas exhaust tube 231 are provided in the side of the reaction
tube 203 to extend to at least the outer side of the heater
206.
[0060] More particularly, the gas inlet tube 230 is partitioned in
plurality in a direction perpendicular to the processing surface
(main surface) of the wafers 200. In addition, the gas exhaust tube
231 is also partitioned in plurality in a direction perpendicular
to the processing surface of the wafers 200. In addition, the gas
inlet tube 230 and gas exhaust tube 231 are disposed along a
straight line that passes through the diameter of the wafers 200
disposed in the reaction tube 203.
<<Reaction Tube>>
[0061] As shown in FIG. 1, the processing furnace 202 comprises a
reaction tube 203. The reaction tube 203 is installed vertically.
The reaction tube 203 is constituted from, for example, a
heat-resistant glass material such as quartz (SiO.sub.2) or silicon
carbide (SiC) or the like formed in a cylindrical shape with a
closed upper end and open lower end. The processing chamber 201 is
formed in the interior of the reaction tube 203. The reaction tube
203 is configured to be able to process the wafers 200 with the
wafers 200 disposed in a wafer processing space 204 in a state of
horizontal alignment in a multiple number of regular stages in the
vertical direction by means of a later-described substrate-holding
tool. The wafer processing space 204 referred to here describes the
space within the processing chamber 201 in which the wafers 200 are
actually processable.
<<Gas Introduction Pipe Gas Discharge Pipe>>
[0062] A gas inlet tube 230 for introducing gas into the reaction
tube 203 and a gas exhaust tube 231 for exhausting gas from the
reaction tube 203 are provided in the side of the reaction tube
203. The gas inlet tube 230 and gas exhaust tube 231 are formed
from a material identical to that used for the reaction tube 203,
and are horizontally disposed in a straight line that passes
through the center of the wafers 200 disposed in the reaction tube
203. The gas inlet tube 230 and gas exhaust tube 231 are provided
along the outer side of the later-described heater 206 for the
purpose of introducing and exhausting the introduced gas and
exhaust gas in a horizontal direction to and from the wafer
processing space 204, and to provide a gas entrance region parallel
to the processing surface of the wafers 200 prior to the gas
reaching the interior of the reaction tube 203. In addition,
a gas spouting port 212 is disposed in the gas inlet tube 230 in a
slit form so as to straddle at least a plurality of wafers 200 in a
direction perpendicular to the processing wafer surface, for
spouting gas from the gas inlet tube 230 into the wafer processing
space 204. In addition, a gas exhaust port 213 is disposed in the
gas exhaust tube 231 a slit form so as to straddle at least a
plurality of wafers 200 in a direction perpendicular to the
processing wafer surface, for exhausting gas from the wafer
processing space 204 into the gas exhaust tube 231.
[0063] Here, employing the gas inlet tube 230 and the gas exhaust
tube 231 of the reaction tube 203 provided lengthwise along the
side thereof, and a slit formed gas spouting port 212 formed to
straddle at least a plurality of wafers 200 in a direction
perpendicular to the processing wafer surface, for spouting gas
from the gas inlet tube 230 to the processing chamber 201, a more
streamlined gas flow is more likely to be produced and, in
addition, a single direction gas flow can be produced, and the
amount of gas flowing across the wafers 200 can be made uniform.
Accordingly, a gas of uniform density and velocity can be fed
across the wafers, and the in-plane and interwafer film thickness
uniformity improved. In addition, gas can be supplied to the wafers
without a drop in velocity of the gas occurring between the
upstream side tip-end portion of the gas supply pipe and the
substrate.
[0064] The gas inlet tube 230 and gas exhaust tube 231 of the first
embodiment describe a flat body shape. For example, as shown in
FIG. 3, they describe a long, narrow elliptical shape that traces
the axial direction of the reaction tube 203. The gas inlet tube
230 and gas exhaust tube 231 are provided in positions in the side
of the reaction tube 203 opposing the wafer processing space 204.
The gas inlet tube 230 and the gas exhaust tube 231 are connected
to the sides of the reaction tube 203 horizontally. The gas inlet
tube 230 and gas exhaust tube 231 are integrally connected to the
reaction tube 203 in such a way that the axes of the two pipes lie
along a straight line. This integrated connection may be provided
by, for example, a solder connection. By provision of the gas inlet
tube 230 and gas exhaust tube 231 in the side of the reaction tube
203 in this way, the flow of gas into the processing chamber 201 is
produced as a side flow.
[0065] The gas inlet tube 230 comprises gas introduction partition
portions obtained by the partition thereof in plurality in a
direction perpendicular to the processing surface of the wafers
200, gas being caused to flow to each of these gas introduction
partition portions. In addition, a gas spouting port 212 is formed
in each of these gas introduction partition portions. In the
example shown in this diagram, the gas inlet tube 230 comprises
eight gas introduction partition portions 230a to 230h partitioned
by partition walls 228.
[0066] In addition, process gas supply portions 249a to 249h and
first inert gas supply portions 250a to 250h connect to the
upstream side of the plurality of gas introduction partition
portions 230a to 230h respectively of the gas inlet tube 230.
[0067] By virtue of this, in the processing of wafers 200 in the
reaction tube 203, a process gas can be supplied to the process gas
supply portions 249a to 249h if wafers 200 are arranged in any of
the positions of the wafer processing space 204 opposing the gas
introduction partition portions 230a to 230h, and an inert gas, for
example an N.sub.2 gas, can be supplied from the first inert gas
supply portions 250a to 250h if there are no wafers 200 disposed in
any of the positions of the wafer processing space 204 opposing the
gas introduction partition portions 230a to 230h.
[0068] The gas exhaust tube 231 comprises gas exhaust partition
portions partitioned in plurality in a direction perpendicular to
the processing surface of the wafers 200, exhaust from the wafer
processing space 204 occurring through these gas exhaust partition
portions. In addition, gas exhaust ports 213 are formed in each of
the gas exhaust partition portions. In the example shown in this
diagram, the gas exhaust tube 231 comprises eight gas exhaust tubes
231a to 231h partitioned by partitioned walls 229. The gas exhaust
partition portions 231a to 231h and gas introduction partition
portions 230a to 230h of the gas exhaust tube denoted by equivalent
symbols are opposingly provided horizontally about the reaction
tube 203.
[0069] As a result, in the processing of the wafers 200 in the
reaction tube 203, a process gas can be exhausted from the gas
exhaust tubes 231a to 231h if wafers 200 are arranged in any of the
positions of the wafer processing space 204 opposing the gas
introduction partition portions 231a to 231h, and an inert gas can
be exhausted from the gas exhaust tubes 231a to 231h if there are
no wafers 200 disposed in any of the positions of the wafer
processing space 204 opposing the gas exhaust tubes 231a to
231h.
[0070] The abovementioned gas spouting ports 212 are provided only
on the downstream side of the gas inlet tube 230, and preferably
none of the abovementioned gas spouting ports 212 are segmented.
That is to say, only one gas spouting port 212 needs to be provided
at each location of a gas introduction partition of the gas inlet
tube 230. While from the viewpoint of the strength of the gas inlet
tube 230 the gas spouting ports 212 are preferably segmented, the
provision of such segments results in greater likelihood of the gas
flowing along the gas inlet tube 230 and colliding with these
segments. This results in, for example, blockage of these segmented
areas by the reaction product generated by pre-heating and so on of
the process gas and, as these uniformly segmented areas cannot be
cleaned during the cleaning process, changes over time in these
segmented areas are unavoidable. A particular drawback associated
with a change in size of these segmented areas over time resides in
the differences in film state of films formed subsequent to these
changes having occurred over time.
[0071] In contrast, the employment of non-segmented gas spouting
ports 212 means that a single gas spouting port is provided for
each gas introduction partition portions of the gas inlet tube 230,
and that the flow rate flowing in each gas introduction partition
portions is spouted through a single gas spouting port. In
addition, while during rotation of the wafers 200 in which the area
across the wafers 200 is regarded as the target there is tendency
for the flow velocity to be slower at the center portion of the
wafers 200 due to the distance from the gas spouting ports 212 to
the center portion of the wafers 200 being the longest, no drop in
gas flow velocity occurs when the flow rate flowing into individual
gas introduction partition portions is spouted through individual
gas spouting ports 212 and, furthermore, the gas caused to reach
the center of the wafers 200 is of a uniform heat quantity
state.
[0072] The opening area of the aforementioned gas spouting ports
212 is preferably the same as the cross-sectional area of the gas
introduction partition portions in a direction perpendicular to the
processing wafer surface. By virtue of this, the supply of gas can
be smoothly implemented and, furthermore, the drawbacks described
above can be avoided. A diaphragm portion may be provided in one of
the gas spouting ports 212 to ensure the opening area of the gas
spouting port 212 is less than the cross-sectional area of the gas
introduction partition in a direction perpendicular to the wafer
processing surface. The gas flow velocity can be further increased
as a result. In this case, a change in the cross-sectional area A'
of the gas spouting port 212 of the inner wall portion of the
reaction tube 203 from the cross-sectional area A of the gas
introduction orifice 211 of the gas inlet tube 230 of A=A' or
A>A' should be established.
<<Heater>>
[0073] The processing furnace 202 comprises a heater 206 serving as
a heating device. The heater 206 is cylindrical in shape and is
provided to cover the outer circumference of the reaction tube 203.
The heater 206 is vertically installed and supported by a heater
base 251 serving as a holding plate. The reaction tube 203 is
formed in a vertically-installed state supported by the heater base
251.
[0074] The heater 206 comprises a cylindrical heat-insulating body
260 of which the upper part thereof is closed and the lower part is
open, a gas inlet tube introduction inlet 261 formed to lead the
gas inlet tube 230 horizontally to the outer side of the heater 206
from the side of the reaction tube 203, and a gas exhaust tube
exhaust outlet 262 formed to lead the gas exhaust tube 231
horizontally from the side of the reaction tube 203 to the outer
side of the heater 206.
[0075] The introduction inlet 261 and exhaust outlet 262 are
provided as, for example, groove-shaped notch portions formed
upward from the lower end of the heat insulating body 260.
[0076] By virtue of this, when the heater 206 is mounted on the
reaction tube 203 from above to cover the reaction tube 203, the
outer circumference of the reaction tube 203 can be covered in the
absence of any interference by the heater 206 with the gas inlet
tube 230 and the gas exhaust tube 231 provided in the side of the
reaction tube 203.
[0077] A result of the heater 206 covering the outer circumference
of the reaction tube 203 is to cause end portions on the opposing
side to the connection portion with the reaction tube of the gas
inlet tube 230 and the gas exhaust tube 231 that extend to the
outer side of the heater 206 to protrude outward from two sides of
the heater 206.
[0078] The following advantages comparative to the case of the
prior art are afforded by the formation of the introduction inlet
261 and exhaust outlet 262 as groove-like notch portions from the
lower end upward of the heat-insulating body 260 as described
above. When a gas nozzle or the like is provided upright from the
lower end within the heater to supply gas as is the case in the
prior art, gas is heated within the gas nozzle and, depending on
the height of the gas nozzle and the height of the wafers arranged
in the perpendicular direction, differences in the temperature of
the process gas across the plurality of wafers are produced.
However, as a result of notch portions that extend along the entire
wafer processing region being formed in the heater and the gas
inlet tube 230 and gas exhaust tube 231 being inserted in these
notch portions, when the gas inlet tube 230 and the gas exhaust
tube 231 are disposed horizontally to the wafers 200, the
temperature of the process gas between wafer surfaces, that is to
say, between a plurality of wafers being simultaneously processed,
can be made uniform.
[0079] A heat-emitting body is provided in the heat-insulating body
260. As shown in FIG. 2, the heat-emitting body is configured from
a first heat-emitting body 266 for heating the reaction tube 203, a
second heat-emitting body 267 for heating the gas inlet tube 230,
and a third heat-emitting body 268 for heating the gas exhaust tube
231.
[0080] The first heat-emitting body 266 is provided between the
inner wall of the heat-insulating body 260 and the reaction tube
203. Similarly to the prior art, the first heat-emitting body 266
is segmentally provided in two areas between the inner wall of the
heat-insulating body 260 and the reaction tube 203 along the inner
wall of zonally divided zones in the vertical direction, and is not
provided in the introduction inlet 261 and the exhaust outlet 262.
The second heat-emitting body 267 is provided between the
introduction inlet 261 and the gas inlet tube 230 using a fastening
bracket 271. The third heat-emitting body 268 is provided between
the exhaust outlet 262 and the gas exhaust tube 231 using a
fastening bracket 272. The first heat-emitting body 266 is
configured from, for example, a resistance-heating heater, and the
second heat-emitting body 267 and third heat-emitting body 268 are
configured from, for example, an infrared lamp.
<<Mechanism>>
[0081] A seal cap 219 is provided below the reaction tube 203 as a
furnace opening cover for airtight-closing the lower-end opening of
the reaction tube 203. A rotary mechanism 254 for rotating a
later-described port 217 serving as a substrate holding tool is
disposed in the opposite side of the processing chamber 201 to the
seal cap 219. A rotating shaft 255 of the rotary mechanism 254
passes through the seal cap 219 and connects to the port 217, and
is configured to rotate the wafers 200 as a result of the port 217
being rotated. While not shown in FIG. 1, the port 217 is able to
be conveyed in and out of the processing chamber 201 by a port
elevator serving as an elevating mechanism.
<<Port>>
[0082] The port 217 serving as the substrate holding tool is
constituted from a heat-resistant glass material such as quartz
(SiO.sub.2) or silicon carbide (SiC), and is configured to hold a
plurality of wafers 200 in a multiple number of regular stages in
the vertical direction in a state of horizontal alignment with
centers thereof aligned. More specifically, the port 217 comprises
a plurality of supports 217a arranged in a cylindrical shape to
support the outer circumferential portion of the wafers 200, and a
ceiling plate 217b for closing an upper part between the plurality
of supports 217a, and a bottom plate 217c for closing a lower part
between the plurality of supports 217a. A plurality of
heat-insulating plates, in the same shape as the wafers 200,
constituted from a heat-resistant glass material such as quartz
(SiO.sub.2) or silicon carbide (SiC) or the like serving as
heat-insulating portions 216 are disposed in a lower part of the
port 217, and are configured to inhibit the transfer of heat from
the heater 206 below the reaction tube 203.
[0083] The processing furnace 202 of the present embodiment is
configured as described above.
<<Method of Thin Film Formation>>
[0084] As one process for manufacturing a semiconductor device, a
method for forming a thin film on the wafers 200 at a reduced
pressure using a CVD method employing the processing furnace 202 of
the configuration described above will hereinafter described.
<<Inward Conveyance Process>>
[0085] A plurality of wafers 200 are packed into the port 217
(wafer charge) and, as shown in FIG. 1, the port 217 on which the
plurality of wafers 200 are held is lifted up by the port elevator
and conveyed inward into the processing chamber 201 (port loading).
In this state, the seal cap 219 forms a state in which it seals the
lower end of the reaction tube 203. In addition, as a result of
this port loading, wafers 200 are disposed in predetermined
positions of the wafer processing space 204 opposing the gas
introduction partition portions 230a to 230h. In this case, in
order to more reliably ensure the establishment of a side flow into
the wafer processing space 204 from each of the gas introduction
partition portions 230a to 230h, the wafer processing space 204 is
preferably partitioned to conform to the partition portions of the
gas inlet tube 230 and the gas exhaust tube 231, and the wafers 200
are preferably disposed in positions opposing the partition walls
228 of the gas inlet tube 230 and the partition walls 229 of the
gas exhaust tube 231. <<Pressure, Temperature Stabilization
Process>>
[0086] A vacuum exhausting is performed in the processing chamber
201 by way of the gas exhaust tube 231 to establish a desired
pressure (vacuum degree) thereof. In addition, the processing
chamber 201 is heated by the heater 206 to establish a desired
temperature thereof. Thereafter, the wafers 200 are rotated as a
result of the port 217 being rotated by the rotary mechanism
254.
<<Gas Introduction Process, Substrate Processing Process, Gas
Discharging Process>>
[0087] Next, process gas is supplied from the process gas supply
portions 249a to 249h and introduced into the wafer processing
space 204 by way of the gas introduction partition portions 230a to
230h of the gas inlet tube 230. In this case, if wafers 200 are
disposed in any position in the wafer processing space opposing the
gas introduction partition portions 230a to 230h, a process gas is
supplied through the process gas supply portions 249a to 249h.
[0088] If there are no wafers 200 disposed in any position in the
wafer processing space opposing the gas introduction partition
portions 230a to 230h, an inert gas is introduced through first
inert gas supply portions 250a to 250h.
[0089] The introduced gas passes through the processing chamber 201
in the horizontal direction, and is exhausted from gas exhaust
partition portions 231a to 231h of the gas exhaust tube 231. The
gas passing through the processing chamber 201 comes into parallel
contact with the processing surface of the rotating wafers 200, an
accumulation (deposition) of the thin film on the surface of the
wafers 200 occurring at this time as a result of a thermal CVD
reaction.
<<Normal Pressure Restoration Process>>
[0090] Subsequent to a pre-set processing time having elapsed, an
inert gas is supplied from the first inert gas supply portions 250a
to 250h, the interior of the processing chamber 201 is substituted
with the inert gas, and the pressure of the processing chamber 201
is restored to normal pressure.
<<Outward Conveyance Process>>
[0091] Subsequently, the seal cap 219 is lowered to open the lower
end of the reaction tube 203 whereupon the processed wafers 200, in
a held state on the port 217, are conveyed outward through the
lower end of the reaction tube 203 (port unloading). The processed
wafers 200 are then removed from the port 217 (wafer exhaust).
Effects of the First Embodiment
[0092] One or more of the following effects are exhibited by the
first embodiment described above.
<<Improved In-Plane and Interwafer Processing
Uniformity>>
[0093] According to the first embodiment, because the gas inlet
tube 230 and the gas exhaust tube 231 are horizontally connected to
the side of the reaction tube 203, gas can be supplied to and
exhausted from the reaction tube 203 in the horizontal direction (a
side flow can be established). Accordingly, the gas supplied via
the gas inlet tube 230 is supplied in a direction that is parallel
to the processing surface of the wafers 200 and, accordingly, the
gas flows more readily across the wafers 200.
[0094] Because the gas inlet tube 230 and the gas exhaust tube 231
are provided to extend to the outer side of the heater 206 from the
side of the reaction tube 203, compared to examples when the gas
inlet tube 230 and the gas exhaust tube 231 are not provided to
extend to the outer side of the heater 206 such as when they are
provided in the interior of the reaction tube 203 or when they are
provided between the heater 206 and the reaction tube 203, the
diameter of the reaction tube 203 can be reduced. Because the gas
flows through a space through which gas flows readily, reducing the
diameter of the reaction tube 203 results in a more ready flow of
film formation gas across the wafers 200.
[0095] Furthermore, the gas inlet tube 230 and gas exhaust tube 231
are symmetrically provided about the wafers 200 disposed in the
processing chamber 201. Accordingly, the in-plane and interwafer
processing uniformity of the wafers 200 disposed in the processing
chamber 201 is improved.
[0096] More particularly, because the gas inlet tube 230 and the
gas exhaust tube 231 are disposed in a straight line to pass
through the diameter of the wafers 200 disposed in the reaction
tube 203 so that the gas introduction partition portions 230a to
230h that serve as gas entrance regions prior to the gas arriving
into the reaction tube 203 are established in a direction parallel
to the processing surface of the wafers 200, the gas flows even
more readily across the wafers 200, and the in-plane processing
uniformity of the simultaneously processed plurality of wafers 200
is further improved.
[0097] In addition, the gas inlet tube 230 and the gas exhaust tube
231 are partitioned in plurality in a direction perpendicular to
the processing surface of the wafers 200 into gas introduction
partition portions 230a to 230h into which the film formation gas
flows. In addition, by virtue of the process gas introduced from
each of the plurality of gas introduction partition portions 230a
to 230h of the gas inlet tube 230 being exhausted through the
plurality of gas exhaust partition portions 231a to 231h of the gas
exhaust tube 231, the film formation gas flows in parallel as shown
by the arrows into a plurality of areas of the wafer processing
space 204 in a direction perpendicular thereto. Because, as a
result, the process gas is supplied in a horizontal direction to
the wafers 200 and exhausted in a horizontal direction therefrom,
the process gas is smoothly supplied across the wafers 200.
Accordingly, the interwafer processing uniformity of a plurality of
simultaneously processed wafers 200 is further improved.
[0098] The similar provision of the gas introduction partition
portions 231a to 231h in the direction of lamination of the wafers
200 in the gas exhaust tube 231 in addition to the partition
portions provided in the gas inlet tube 230 ensures further
improvement in the in-plane and interwafer processing uniformity of
the plurality of wafers 200.
<<Loading Effect>>
[0099] In addition, by virtue of the film formation gas being
introduced in a direction parallel to the processing surface of the
wafers 200 and the film formation gas being caused to flow
uniformly between the large number of wafers 200 on which a film is
being simultaneously performed, a loading effect (a phenomenon in
which the gas amount decreases accompanying the advancement of, for
example, the film formation gas through the processing chamber due
to the film formation gas reacting with the wafers in the
processing chamber and, comparing the wafers on the film formation
gas upstream side with those on the downstream side, the film
formed on the wafers on the upstream side is thicker than the film
formed on the wafers on the downstream side) can be prevented.
<<Dummyless>>
[0100] In addition, a dummyless processing is facilitated by the
absence of a loading effect. This dummyless processing will be
hereinafter described.
[0101] A shift in recent years in the production mode employed in
methods of manufacturing IC from the large-volume production of a
small number of article types to the small-volume production of a
large number of article types has led to a demand for reduced time
from the start to the completion of the manufactured article. For
example, in CVD apparatuses employed for the large-volume
manufacture of a single manufactured article such as a DRAM, the
number of wafers 200 loaded on the port 217 is referred to as the
port maximum loading number. However, for small-volume production
of a large number of article types such as for system LSI, it is
difficult to maintain the number of wafers 200 loaded on the port
to the port maximum loading number and, because this number is
sometimes only 50 to 70% of the port maximum loading number and, in
extreme cases, a mere 2 or 3 wafers may be loaded, there need for
some kind of processing to be implemented.
[0102] In such cases, in order for variations between films of a
single processing operation (hereinafter referred to as a batch), a
uniformity control of the processing conditions between batches is
normally executed. For example, if the number of wafers
(hereinafter referred to as manufactured wafers) processed in a
single batch is reduced, a control for replacing the manufactured
wafers in a number equivalent to the number of wafers not formed as
manufactured wafers (hereinafter referred to as dummy wafers) based
on the batch processing conditions at which a reduction in number
occurred being made identical to batch processing conditions in
which no reduction in number occurs is executed.
[0103] According to the present embodiment, because the amount of
film formation gas supplied is made uniform for all wafers, the
need for a dummy wafer to be packed into the processing chamber 201
when the film formation processing is performed is eliminated
(dummyless processing), the film formation gas flows into only the
gas introduction partition portions in which manufactured wafers on
which a film formation processing is to be performed are present, a
purge gas flows from the gas introduction partition portions into
the other gas introduction partition portions in which there are no
dummy wafers packed, and the overall gas flow rate is regulated for
film formation. In addition, gas is introduced into each gas
introduction partition portion and, by provision of flow rate
control means for the control of the gas introduction flow rate of
each gas introduction partition portion, the film formation at each
partition can be better controlled.
[0104] By virtue of this, the film formation gas usage amount can
be suppressed and, because the need for a dummy wafer to be
provided for packing into the partition portions is eliminated, the
operating costs (running costs) and so on thereof can be markedly
reduced. In addition, exhausting is performed from each gas exhaust
partition portion and, by provision of automatic pressure control
means and implementation of an automatic pressure control (APC) for
each, the film formation of each partition can be better
controlled.
[0105] In addition, when the loading percentage of the wafers 200
on the port is low, because a process gas is supplied through the
process gas supply portions 249a to 249h if the wafers 200 are
disposed in any position in the wafer processing space opposing the
gas introduction partition portions 230a to 230h, and an inert gas
is supplied through the first inert gas supply portions 250a to
250h if the wafers 200 are disposed in any position in the wafer
processing space opposing the gas introduction partition portions
230a to 230h, the amount of process gas used can be reduced. That
is to say, as an inert gas rather than a process gas is supplied
through the partition portions of the gas supply pipe to positions
in the wafer processing space in which there are no wafers
disposed, attachment and accumulation of a reaction product at
these partition portions in the reaction tube can be
suppressed.
<<Heater Heating >>
[0106] In addition, because the process gas is heated by a first
heat-emitting body 266 and a second heat-emitting body 267 at
entrance regions of the gas introduction partition portions 230a to
230h of the gas inlet tube 230, the process gas can be sufficiently
pre-heated to a temperature at which is reactable whereupon, in
turn, the wafer processing can be efficiently performed. In
addition, liquefaction in the gas inlet tube 230 when starting
materials and so on that liquefy easily at room temperature and
normal pressure are employed as the gas starting materials can be
prevented. In addition, because the third heat-emitting body 268
heats the exhaust gas exhausted from the gas exhaust tube 231,
attachment of the reaction product to the gas exhaust tube 231 can
be prevented.
[0107] Furthermore, even when gas introduction notched portions for
the gas inlet tube 230 and the gas exhaust tube 231 are formed in
the heater 206 by virtue of the second heat-emitting body 267 and
the third heat-emitting body 268 being provided in addition to the
first heat-emitting body 266 as heat-emitting bodies, because the
second heat-emitting body 267 and the third heat-emitting body 268
are separately controllable to the main first heat-emitting body
266 with respect to the heat that escapes from the introduction
port and the exhaust port are provided, the generation of cold
spots in these gas supply pipe notched portions can be effectively
suppressed.
<<Pressure Resistance, Heat Resistance
Improvement>>
[0108] In addition, because partition walls 228, 229 are provided
in a vertical direction in the interior of the gas inlet tube 230
and the gas exhaust tube 231, the pressure resistance and heat
resistance of the gas inlet tube 230 and the gas exhaust tube 231
and, in turn, the reaction tube 203 connected thereto is
improved.
First Embodiment Modifications
[0109] The following range of modifications can be made to the
first embodiment of the present invention described above.
<<Gas Introduction Pipe and Gas Discharge Pipe
Modifications>>
[0110] While the first embodiment described above describes, as
shown in FIG. 3, a case in which a plurality of gas introduction
partition portions 230a to 230h and gas exhaust partition portions
231a to 231h are integrally provided in a single gas inlet tube 230
and a single gas exhaust tube 231a as a result of these long,
elliptically-shaped pipes being partitioned in the vertical
direction by partition walls 228, 229, the present invention is not
limited thereto.
[0111] For example, as in a first modification thereof shown in
FIG. 4, on the basis of a plurality of gas inlet tubes 230 and gas
exhaust tubes 231 of a cylindrical shape being arranged in rows in
the vertical direction of the reaction tube 203 and joined by way
of common flanges 232, 233, the plurality of gas introduction
partition portions 230a to 230h and gas exhaust partition portions
231a to 231h may be independently provided.
[0112] In addition, as in the modification shown in FIG. 5, an
arrangement in which a plurality of partition portions are
integrally provided in one of either the gas inlet tube 230 or the
gas exhaust tube 231, and in which a plurality of partition
portions are independently provided in the other may be employed.
FIG. 5A shows a second modification which describes an arrangement
in which a plurality of gas introduction partition portions 230a to
230h are integrally provided in the gas inlet tube 230 and a
plurality of gas exhaust partition portions 231a to 231h are
independently provided in the gas exhaust tube 231. FIG. 5B shows a
third modification which describes an arrangement in which a
plurality of gas introduction partition portions 230a to 230h are
independently provided in the gas inlet tube 230 and a plurality of
gas exhaust partition portions 231a to 231h are integrally provided
in the gas exhaust tube 231.
[0113] Furthermore, the shape of the gas inlet tube 230 and the gas
exhaust tube 231 is not limited to the shape shown in the examples
of FIG. 3 to FIG. 5. In addition, the arrangement and number of
partition portions is not limited to the arrangement and number
shown in the examples of these drawings.
<<Plasma Excitation>>
[0114] In some CVD methods the process gas introduced into the
reaction tube is subject to plasma excitation to promote the
reactivity thereof. FIG. 6 is a lateral cross-sectional view of a
processing furnace of a fourth modification that comprises this
plasma excitation function.
[0115] As shown in FIG. 6, a plasma excitation source 274 is
provided in the gas inlet tube 230. In order to avoid interference
between the gas inlet tube 230 and the second heat-emitting body
267 provided in the reaction tube connecting portion side, the
plasma excitation source 274 is provided in a side opposing the
reaction pipe connection portion side of the gas inlet tube 230.
The plasma excitation source 274 comprises, for example, parallel
flat plate electrodes 275.
The parallel flat plate electrodes 275 are provided along the flat
two side walls of the gas inlet tube 230 to sandwich therebetween
the left and right faces of the gas inlet tube 230.
[0116] As shown in FIG. 7, the plasma excitation source 274 is
configured from, for example, an alternating current power supply
277, an LC circuit 279 for generating an oscillating voltage signal
of the alternating current power supply 277 of which the voltage
rise thereof is produced by a transistor 278, and the parallel flat
plate electrodes 275 to which an oscillating power from the LC
circuit 279 is imparted.
[0117] Plasma is generated in gas entrance regions of the gas
introduction partition portions of the gas inlet tube 230 by the
plasma excitation source 274 described above. The plasma generated
in the gas entrance regions excites the gas introduced through the
gas inlet tube 230. This excitation gas of increased reactivity
affords the formation of a film on the wafers 200, and is then
exhausted from the gas exhaust tube 231.
[0118] Because the parallel flat plate electrodes 275 are disposed
outside the processing chamber and provided to surround the long,
narrow elliptically-shaped gas inlet tube 230 in this way, the gas
in the gas inlet tube 230 is created as a plasma, and then the
plasma-excited gas can be easily supplied to the substrate.
<<Reduction in Film Formation Gas Usage Amount>>
[0119] However, as in the fifth modification shown in FIG. 8, to
ensure the satisfactory pressure resistance of the reaction tube
203, the upper part of the cylindrical reaction tube 203 having a
processing chamber in its interior in which a plurality of wafers
200 are processable is normally configured as a dome shape. A
problem inherent thereto resides in the film formation gas flowing
into the dome-shaped upper space 208 of the reaction tube 203 and
being exhausted without contributing to film formation. There is a
particular problem inherent to the employment of a side-flow type
reaction tube 203 in that, because a flow of film formation gas
into the uppermost level partition is produced, there is an
increased film formation gas usage amount at this partition which
creates a flow rate imbalance with respect to the gas flow rate
flowing through the other partition levels. An additional problem
resides in the attachment and accumulation of reaction product on
the inner wall of the upper space 208 when the film formation gas
flows into the upper space 11.
[0120] Thereupon, in the fifth modification shown in FIG. 8, the
ceiling plate 217b of the port 217 is disposed at the same height
as the upper end of the gas inlet tube 230. By virtue of the
ceiling plate 217b of the port 217 being disposed at the same
height as the upper end of the gas inlet tube 230, the side flow of
the process gas supplied from the gas inlet tube 230 into the
reaction tube 203 is undisturbed and, accordingly, readily flow of
the process gas from above the ceiling plate 217b of the gas inlet
tube 230 is inhibited.
[0121] However, the configuration of the fifth modification as
shown in FIG. 8 does not imply that the path (gas flow-passing
space) to the upper space 208 of the reaction tube 203 is
interrupted, and there remains scope for further improvement
thereto.
[0122] Thereupon, in an improved mode thereof, a gas interrupting
portion for interrupting the flow of gas into the upper space 208
is provided above the wafer processing space 204 of the reaction
tube 203 in addition to the ceiling plate 217b of the port 217
disposed at the same height as the upper end of the gas inlet tube
230. In this case, the gas interrupting portion may be either
provided in the interior of the reaction tube 203, or configured as
the outer wall of the reaction tube 203. The provision of the gas
interrupting portion above the wafer processing space 204 of the
reaction tube 203 prevents flow of the process gas above the wafer
processing space 204 of the reaction tube 203 and, accordingly,
resolves the problems described above.
[0123] When a gas interrupting portion is provided above the wafer
processing space 204 of the reaction tube 203, a reinforcing member
extending in a direction perpendicular to the processing surface of
the wafers 200 for reinforcing the pipe wall of the reaction tube
203 is provided. The provision of a reinforcing member in the gas
interrupting portion improves the pressure resistance of the
reaction tube 203.
[0124] In a configuration in which the abovementioned gas
interrupting portion is provided above the wafer processing space
204 of the reaction tube 203 as in, for example, a sixth
modification shown in FIG. 9, a partition panel 282 is provided as
a gas interrupting portion between the upper space 208 (upper
region) of the reaction tube 203 and the wafer processing space 204
(wafer processing region). A plurality of ribs 283 serving as
reinforcing members for reinforcing the wall of the reaction tube
203 extending in a direction perpendicular to the processing
surface of the wafers 200 are provided between the partition panel
282 and the wall of the reaction tube 203 for reinforcing the wall
of the reaction tube 203. The provision of a partition panel 282 in
the inner side of the reaction tube 203 in this way allows for the
effective utilization of a known dome-shaped upper part reaction
tube 203.
[0125] In a configuration in which the gas interrupting portion is
configured as the outer wall of the reaction tube 203 as in, for
example, a seventh modification shown in FIG. 10, the upper part of
the reaction tube 203 is formed in a flat shape, and a flat upper
part 284 thereof serves as the gas interrupting portion. Ribs 285
serving as reinforcing members are provided upright in the outer
side of the flat upper part 284. Configuring the wall of the
reaction tube 203 with a flat upper part 284 in this way affords a
reaction tube 203 of simpler configuration than the configuration
thereof shown in FIG. 9.
[0126] The employment of a reaction tube 203 in which ribs 283, 285
are employed to afford satisfactory pressure resistance of the
sixth and seventh modifications described above inhibits the flow
of the process gas supplied from the gas inlet tube 230 into the
reaction tube 203 upward from the ceiling plate 217b of the
reaction tube 203. Accordingly, the film formation gas usage amount
and the frequency of implementation of a cleaning process for
cleaning the reaction product that attaches to the wall surface
facing the upper space 208 can be reduced. In addition, the
cleaning gas usage amount can be reduced.
[0127] While in the sixth and seventh modifications shown in FIG. 9
and FIG. 10 described above the partition panel 282 and flat upper
part 284 reinforced by the ribs 283, 285 are provided as means for
preventing the flow of film formation gas into the upper space 208
of the reaction tube 203, the configuration is not limited
thereto.
[0128] For example, in an eighth modification shown in FIG. 11, in
addition to the ceiling plate 217b of the port 217 being disposed
at the same height as the upper end of the gas inlet tube 230, as
indicated by the circle symbols, the outer diameter of the ceiling
plate 217b of the port 217 is formed in a size that is at least the
size of the wafers 200 in order to reduce the gap between the
ceiling plate 217b and the reaction tube 203. More preferably, the
gap with the reaction tube 203 inner wall is further reduced by
increasing the outer diameter of the ceiling plate 217b beyond the
cylindrical diameter of the cylindrical shape defined by the
plurality of supports 217a.
[0129] In addition, in a ninth modification shown in FIG. 12, in
addition the ceiling plate 217b of the port 217 being disposed at
the same height as the upper end of the gas inlet tube 230, as
indicated by the circle symbols, the upper end of the gas inlet
tube 230 comprises a protruding portion 234 that protrudes in a
diametric direction from the inner wall surface of the reaction
tube 203 in order to reduce the gap with the ceiling plate
217b.
[0130] While there is no comparative improvement in pressure
resistance of the reaction tube 203 afforded by the eighth and
ninth modifications with respect to the sixth and seventh
modifications, these embodiments afford the prevention of the flow
of the film formation gas into the upper space 208 of the reaction
tube 203 in a comparative simpler configuration.
[0131] In addition, as shown in FIG. 12, a protruding portion 234
that protrudes inward from the inner wall surface of the reaction
tube 203 provided in the upper end of the gas exhaust tube 231
inhibits the process gas being exhausted from the reaction tube 203
into the gas exhaust tube 231 from flowing readily into the upper
space 208 of the reaction tube 203.
[0132] While the embodiments described above address the problem of
gas flowing into the upper space 208 of the reaction tube 203, gas
flows not only into the upper space 208 but also into a lower space
210 of the reaction tube 203.
[0133] Thereupon, as in a tenth modification shown in FIG. 13, a
bottom plate 217c of the port is disposed at an equivalent height
to the lower end of the gas inlet tube 230. By virtue of the bottom
plate 217c of the port 217 being disposed at equivalent height to
the lower end of the gas inlet tube 230, the flow of a process gas
supplied from the gas inlet tube 230 to the reaction tube 203 below
the bottom plate 217c of the reaction tube 203 is inhibited.
[0134] However, the tenth modification shown in FIG. 13 does not
imply that the path (gas flow-passing space) to the lower space 210
of the reaction tube 203 is interrupted, and there remains scope
for further improvement thereto.
[0135] Thereupon, as in an eleventh modification shown in FIG. 14,
the outer diameter of the bottom plate 217c of the port 217 is
formed of a size that is at least the size of the wafers 200 in
order to reduce the gap between the bottom plate 217c and the
reaction tube 203. More preferably, the gap with the reaction tube
203 inner wall is further reduced by increasing the outer diameter
of the bottom plate 217c beyond the cylindrical diameter of the
cylindrical shape defined by the plurality of supports 217a.
[0136] In addition, in a twelfth modification shown in FIG. 15, in
addition to the bottom plate 217c of the port 217 being disposed at
the same height as the upper end of the gas inlet tube 230, the
lower end of the gas inlet tube 230 comprises a protruding portion
244 that protrudes in a diametric direction from the inner wall
surface of the reaction tube 203 to reduce the gap with the bottom
plate 217b. Accordingly, the flow of process gas supplied from the
gas inlet tube 230 into the reaction tube 203 below the bottom
plate 217c of the port 217 of the reaction tube 203 can be
inhibited.
[0137] In addition, as shown in FIG. 15, a protruding portion 244
that protrudes inward from the inner wall surface of the reaction
tube 203 provided in the lower end of the gas exhaust tube 231
inhibits the process gas being exhausted from the gas inlet tube
230 into the gas exhaust tube 231 from flowing readily below the
bottom plate 217c of the reaction tube 203.
[0138] Accordingly, the film formation gas usage amount and the
frequency of implementation of a cleaning process for cleaning the
reaction product that attaches to the wall surface facing the lower
space 210 can be reduced. In addition, the cleaning gas usage
amount can be reduced. Furthermore, compared to the formation of a
port 217 on which wafers 200 are disposed in plurality in a
direction perpendicular to the wafer processing surfaces, the
provision of a protruding portion 244 that protrudes inward from
the inner wall surface of the reaction tube 203 in the upper end
and lower end of the gas inlet tube 230 and gas exhaust tube 231
affords a simpler structure.
<<Purge Gas>>
[0139] According to the embodiments described above, flow of gas
into the upper space 208 and lower space 210 of the reaction tube
203 can be reliably prevented. However, there is scope for
improvement in terms of more reliably preventing the flow of gas
into the upper space 208 and lower space 210 of the reaction tube
203.
[0140] Thereupon, in a thirteenth modification shown in FIG. 16, a
purge gas-introducing gas nozzle 247 serving as a second inert gas
supply portion is provided separately to the gas inlet tube 230 for
film formation gas. This gas nozzle 247 is provided to extend
upward from below the reaction tube 203 along the outer side wall
of the reaction tube 203 to communicate with the upper space 208 of
the dome-shaped apex portion. A shower plate 243 in which a large
number of holes are formed is provided in the upper space 208 of
the reaction tube 203. An inert gas, for example an N.sub.2 gas, is
introduced through the gas nozzle 247 as shown by the arrows into
the upper space 208 of the reaction tube 203, supplied above the
ceiling plate 217b of the port 217 by way of the large number of
holes provided in the shower plate 243, and prevents flow of film
formation gas above the ceiling plate 217b. While the second inert
gas supply portion is provided to supply gas by way of the shower
plate 243 into the upper space 208 within the reaction tube 203,
this gas supply system is not limited thereto. That is, the
provision of the second inert gas supply portion need only ensure
the supply of an inert gas above the wafer processing space of the
reaction tube 203.
[0141] It is preferable that a gas supply pipe 248 serving as a
third inert gas supply portion is connected to a seal cap 219 in
such a way as to communicate with the processing chamber 201 and,
as shown by the arrows, that an inert gas such as an N.sub.2 gas is
introduced through the gas supply pipe 248 to prevent flow of film
formation gas into the lower space 210 of the bottom plate 217c of
the port 217. While the third inert gas supply portion is provided
so that a gas is supplied from the gas supply pipe 248 connected to
the seal cap 219, this gas supply system is not limited thereto.
That is, the provision of the third inert gas supply portion need
only ensure the supply of an inert gas below the wafer processing
space of the reaction tube 203.
[0142] Because the introduction of a purge gas through these upper
and lower parts of the reaction tube 203 affords the supply of a
purge gas from the opposite direction to the direction of film
formation gas supply and exhaust and interruption to the supply of
film formation gas to regions other than the wafer processing
regions and, because the film formation gas flow rate is adjusted
for film formation, the film formation gas usage amount, the
frequency of implementation of the cleaning process for cleaning
the reaction product attached to the side wall and, in turn, the
cleaning gas usage amount can be further reduced.
[0143] It is preferable that a purge gas be introduced through the
upper part and/or lower part of the reaction tube 203 at times
other than during film formation and, when a purge gas is used for
purging following film formation or atmosphere restoration, the
film formation time can be shortened. In addition, while the
embodiments described above describe examples of film formation
performed under a reduced pressure, the pressure produced in the
furnace is not limited to the pressure employed for thermal
processing and, for example, film formation, oxidation and
annealing treatments may be performed under atmospheric
pressure.
[0144] FIG. 22 is a schematic longitudinal cross-sectional view of
a processing furnace 202 of a vertical-type semiconductor
manufacturing apparatus serving as a substrate processing apparatus
ideal for employment in the second embodiment of the present
invention.
<<Processing Furnace>>
[0145] The processing furnace shown in FIG. 22 describes a separate
mode of processing furnace to the processing furnace shown in FIG.
1. The basic configuration of the processing furnaces is the same,
and the constituent elements of this processing furnace correspond
to those of the processing furnace of the first embodiment
described earlier with reference to FIG. 1. The processing furnace
shown in FIG. 22 differs from the processing furnace shown in FIG.
1 in the point that partition walls equivalent to those provided in
the gas inlet tube and the gas exhaust tube are provided in the
port. FIG. 23 is an expanded view of the main part of this
processing furnace 202. FIG. 24 is a lateral cross-sectional view
of the processing furnace 202 thereof.
<<Partition Walls>>
[0146] Processing partition walls 221 for partitioning the port 217
in plurality in a direction perpendicular to the processing surface
of the wafers 200 are provided in the abovementioned port 217. The
processing partition walls 221 of the port 217 are, for example,
uniformly disposed in a direction perpendicular to the processing
surface of the wafers 200. The processing partition walls 221 are
formed in a disc shape of diameter equivalent to, for example, the
bottom plate 217c and the ceiling plate 217b of the port 217.
[0147] More specifically, as shown in FIG. 23, the processing
partition walls 221 protrude outward toward the inner wall of the
cylindrical reaction tube 203 in a diametric direction from the
plurality of supports 217a disposed in a cylindrical shape. Because
of these processing partition walls 221, the port 217, or to put
this another way, the wafer processing space 204, is partitioned
into a plurality of processing partition portions 220 in the
perpendicular direction, and gas flows into each of these
processing partition portions 220. In the example shown in the
diagram, the wafer processing space 204 comprises eight processing
partition portions 220a to 220h partitioned by the processing
partition walls 221 and, as a result, the flow of film formation
gas from a first processing partition portion 220 into a second
processing partition portion 220, or from the second processing
partition portion 220 into the first processing partition portion
220 can be suppressed. This facilitates a processing of a large
number of more uniform wafers 200.
[0148] The plurality of wafers 200 are supported in a horizontal
state by a plurality of grooves 217d serving as substrate holding
portions formed in each of the plurality of supports 217a of the
port 217.
[0149] For example, as shown in FIG. 25, a plurality of grooves
217d are formed in each of the plurality of supports 217a in such a
way that a plurality of wafers 200 are supportable in each of the
vertically adjacent processing partition portions 220. To ensure a
uniform gap between the plurality of wafers 200, the gap between
the plurality of grooves 217d provided in each of the plurality of
supports 217a of the vertically adjacent processing partition
portions 220 is preferably uniform.
[0150] In addition, the plurality of grooves 217d are formed in
each of the plurality of supports 217a in such a way that a
plurality of wafers 200 are supportable in each of the vertically
adjacent processing partition walls 221 in a direction
perpendicular to the processing surface of the wafers 200 (the
vertical direction in FIG. 25). To ensure a uniform gap across the
plurality of wafers 200 supported in the vertically adjacent
processing partition walls 221 in a direction perpendicular to the
processing surface of the wafers 200 (the vertical direction in
FIG. 25), the gap between the plurality of grooves 217d provided in
each of the plurality of supports 217a of the vertically adjacent
processing partition walls 221 in a direction perpendicular to the
processing surface of the wafers 200 (the vertical direction in
FIG. 25) is preferably uniform.
[0151] The grooves serving as substrate holding portions are not
limited to being formed to recess internally from the surface of
the supports 217a and may be provided as protruding portions or
convex portions formed to protrude from the surface of the supports
217a.
[0152] In addition, in order to ensure gas flows into each of the
partitions, the respective processing partition walls 221 of the
port 217 and gas introduction partition walls 228 corresponding to
the processing partition walls 221 are disposed at an equivalent
height. In addition, to as far as possible ensure a leak-free flow
of gas into the partition portions, the respective processing
partition walls 221 and gas introduction partition walls 228 of the
port 217 are formed in an equivalent thickness. By the
establishment of the processing partition walls 221 and the gas
introduction partition walls 228 of the port 217 of equivalent
height and equivalent thickness in this way, the gas introduction
partition portions are more easily partitioned.
[0153] As a result of the respective process gas supply portions
249a to 249h and inert gas supply portions 250a to 250h being
disposed in a central section of the gas introduction partition
portions 230a to 230h in this way, that is to say, in the middle
between the gas introduction partition walls 228, gas can be more
reliably supplied to the plurality of wafers 200 between the
respective processing partition walls 221.
[0154] In addition, in order to ensure the gas can be exhausted
from each of the partition portions, the respective processing
partition walls 221 of the port 217 and gas exhaust partition walls
229 corresponding to the processing partition walls 221 are
disposed at an equivalent height. In addition, to as far as
possible ensure the leak-free exhaust of gas from the partition
portions, the processing partition walls 221 and gas exhaust
partition walls 229 of the port 217 are formed of equivalent
thickness.
[0155] In addition, the need for all wafers 200 disposed in the
perpendicular direction in the partitioned substrate processing
region 224 between the processing partition walls 221 to be
produced as manufactured wafers is eliminated. For example, the
wafers 200 of the uppermost part and lower most part of the
substrate processing region 224 need not be formed as manufactured
wafers and may be used as dummy wafers. The provision of dummy
wafers ensures uniform manufacture of the wagers of the middle
section and eliminates manufactured wafer waste.
Effects of the Second Embodiment
[0156] One or more of the following effects are exhibited by the
second embodiment described above.
<<Improved In-plane and Interwafer Processing
Uniformity>>
[0157] Because processing partition walls 221 that partition the
port 217 in plurality are provided in the port 217 in a direction
perpendicular to the processing surface of the wafers 200, a film
formation gas can flow through the processing partition walls 221
into each of the partitioned processing partition portions 220. In
addition, because the flow of an unnecessary gas into and out of
the processing partition portions 220 is suppressed by virtue of a
first processing partition portion 220 being partitioned from a
second processing partition portion 220 by a processing partition
wall 221, the appropriate usage gas flow rate in terms of film
formation can be obtained. Accordingly, a loading effect can be
prevented, and the in-plane and interwafer processing uniformity of
the simultaneously processed plurality of wafers 200 is further
improved.
[0158] In addition, because gas introduction partition walls 228
and gas exhaust partition walls 229 for partitioning the gas inlet
tube 230 and the gas exhaust tube 231 into plurality are provided
in the gas inlet tube 230 and gas exhaust tube 231 respectively in
a direction perpendicular to the processing surface of the wafers
200, the introduction and exhaust of gas in a direction horizontal
to the processing partition portions 220 (a side flow) can be
established.
[0159] That is to say, the gas inlet tube 230 and gas exhaust tube
231 are partitioned into plurality in a direction perpendicular to
the processing surface of the wafers 200, and film formation gas
flows into these partitioned gas introduction partition portions
230a to 230h. In addition, by virtue of a process gas introduced
through each of the plurality of gas introduction partition
portions 230a to 230h of the gas inlet tube 230 being exhausted
through each of the plurality of gas exhaust partition portions
231a to 231h of the gas exhaust tube 231, a flow of film formation
gas in parallel to a plurality of areas in a perpendicular
direction of the wafer processing space 204 as shown by the arrows
is formed. Because, as a result, a process gas is supplied from the
direction horizontal to the wafers 200 and exhausted in a direction
horizontal thereto, the process gas can be smoothly supplied across
the wafers 200. Accordingly, a loading effect can be prevented, and
the in-plane and interwafer processing uniformity of the
simultaneously processed plurality of wafers 200 is further
improved.
[0160] In addition, because the partition walls are provided in a
direction perpendicular to the processing surface of the wafers
200, the gas introduced through the gas inlet tube 230 is
introduced in a direction parallel to the processing surface of the
wafers 200 and, accordingly, flows more readily across the wafers
200. Furthermore, because the gas inlet tube 230 and the gas
exhaust tube 231 are disposed on a straight line that passes
through the diameter of the wafers 200 disposed in the reaction
tube 203, the gas introduction partition portions 230a to 230h that
serve as gas entrance regions prior to the gas arriving at the
interior of the reaction tube 203 are established in a direction
parallel to the processing surface of the wafers 200 and,
accordingly, the gas flows even more readily across the wafers 200.
Accordingly, a loading effect can be prevented, and the in-plane
and interwafer processing uniformity of the simultaneously
processed plurality of wafers 200 is further improved.
[0161] In addition, because the processing partition walls 221, gas
introduction partition walls 228 and gas exhaust partition walls
229 of the port 217 are opposingly provided in the same number and
at the same height, the film formation gas can flow uniformly
between the processing partition portions. In addition, because the
wafers 200 are uniformly disposed in the processing partition
portions 220 formed in the port 217, the film formation gas flows
uniformly across the wafers 200 in the processing partition
portions. Accordingly, a loading effect can be prevented, and the
in-plane and interwafer processing uniformity of the simultaneously
processed plurality of wafers 200 is further improved.
[0162] According to this second embodiment, because processing
partition walls 221 are also provided in the port 217, the in-plane
and interwafer processing uniformity of the simultaneously
processed plurality of wafers 200 is improved. However, for example
when there are no processing partition walls 221 provided in the
port 217, there is concern that a flow passage 227 will be formed
between the reaction tube 203 and the port 217 in a direction
perpendicular to the wafer processing surface. For this reason, in
addition to a flow of gas in the horizontal direction in the
processing chamber 201, a flow of gas in a vertical direction that
passes through the flow passage 227 is also formed. That is to say,
when there are no processing partition walls 221 provided in the
port 217, neither the flow of a film formation gas from a first
processing partition portion 220 out to a second processing
partition portion 220 or the introduction of a film formation gas
from the second processing partition portion 220 to the first
processing partition portion 220 within the processing chamber 201
can be suppressed. This creates differences in the flow rate of the
film formation gas between processing partition portions 220 and
affects the in-plane wafer uniformity in the processing partitions
and the interwafer thickness uniformity in the processing partition
portions. These problems are resolved by the embodiment described
above.
[0163] In addition, according to the second embodiment, because the
gas inlet tube is provided in the side of the reaction tube in
order to establish the gas flow as a side flow, the maintenance
characteristics are markedly better than when a gas nozzle is
provided. In addition, because the gas inlet tube is provided on
the outside of the wafer processing space, there is much reduced
attachment and accumulation of reaction product compared to when
the gas inlet tube is provided in the wafer processing space. In
addition, according to the second embodiment, because selective
introduction of either a process gas or an inert gas through the
partitions of the gas inlet tube is possible, altered film
formation conditions can be accommodated without need to alter the
gas inlet tube, and there are no limitations to the conditions in
which a film is formable. Accordingly, by simply carrying out a
desired maintenance or replacement of the gas inlet tube, the
in-plane and inter substrate processing uniformity of a
simultaneously processed plurality of substrates is improved.
Second Embodiment Modifications
[0164] The following range of modifications can be made to the
second embodiment of the present invention described above.
<<Processing Partition Wall Shape, Arrangement and
Number>>
[0165] While the embodiment described above describes an example in
which the processing partition walls provided in the port describe
a disc shape and are formed in a certain arrangement and number in
the port, the shape, arrangement and number of these processing
partition walls is not limited thereto.
<<Assembled Port>>
[0166] In addition, while the port 21 of the embodiment described
above is integrated, an assembled body that is disassemblable into
processing partition units may be adopted. For example, a port 217
formed as a laminate of port constituent elements may be adopted.
The assembly of this port is based on a plurality of port
constituent elements being disposed in an arrangement in which one
port constituent element is placed on another port constituent
element in sequence.
[0167] For example, as in a first modification shown in FIG. 26,
the basic configuration of the port 217 is the same as that of the
previously described configuration. The port 217 is constituted
from port constituent element 290 of equivalent shape that divide
the port 217 in plurality in the height direction thereof. The port
constituent elements comprise a plurality of short supports 290a
arranged in a cylindrical shape to support the outer
circumferential portion of the wafers 200, a cylindrical ceiling
plate 290b for closing the upper part between the plurality of
short supports 290a, and a disc-shaped bottom plate 290c for
closing the lower part between the plurality of short supports
290a. A plurality of grooves serving as substrate holding portions
that support the outer circumferential portion of the wafers 200
are cut into the side of the plurality of short supports 290a.
[0168] A protruding engaging portion 291 is provided in the ceiling
plate 290b and a recessed engaged portion 292 is provided in the
bottom plate 290c so that when a second port constituent element is
placed on a first port constituent element 290 the ceiling plate
290b of the first port constituent element 290 and the bottom plate
290c of the second port constituent element engage. The engaged
portion 292 may be provided in the ceiling plate 290b and the
engaging portion 291 provided in the bottom plate 290c. In
addition, in order for the short supports 290a of the port
constituent element 290 to be sequentially linked, a fit-insertion
mode in which a drill hole is provided in the upper part of the
short supports 290a and a protruding portion that fits into the
drill hole and that protrudes from the lower face of the bottom
plate 290c is provided in the lower part of the short supports 290a
is established between the upper part of the short supports 290a of
a first port constituent element and the lower part of the short
supports 290a of a second port constituent element. The protruding
portion may be provided in the upper part of the short supports
290a and the drill hole provided in the lower part of the short
supports 290a.
[0169] Processing partition walls are constituted from the ceiling
plate 290b and bottom plate 290c described above. This sequentially
placing of one port constituent element 290 on another port
constituent element 290 affords the assembly of a port of a
laminated structure. The processing partition walls of the center
portion of the port excluding the bottom plate 290c and ceiling
plate 290b of the assembled port form a double-layer structure
comprising the ceiling plate 290b of one port constituent element
290 and the bottom plate 290c of another port constituent element
290 placed thereon.
[0170] By virtue of the port being configured from a plurality of
port constituent elements 290 and the port constituent elements 290
being laminated in this way, the port can also be partitioned by
the ceiling plate 290b and the bottom plate 290c that serve as
boundaries between the port constituent elements 290. According to
this embodiment, the laminated number of port constituent elements
can be easily altered in accordance with the number of wafers to be
processed.
<<Gas Discharge Pipe>>
[0171] In addition, while the embodiment described above describes
the provision of not only a gas inlet tube but also a gas exhaust
tube in the side of the reaction tube along the substrate
processing region thereof, the present invention is not limited
thereto. Even though the in-plane and interwafer uniformity is
somewhat worse than when the gas exhaust tube is provided in the
side of the reaction tube along the substrate processing region
thereof, when the reaction vessel is configured from a reaction
tube 203 and a manifold 209, the gas inlet tube 230 may be provided
in the side of the reaction tube 203 and the gas exhaust tube 231
provided in the manifold 209 as in, for example, the second
modification shown in FIG. 27. In this case it is preferable that
gas introduction partition walls 228 that partition the gas inlet
tube 230 in plurality are provided in the side of the reaction tube
203 in a direction perpendicular to the processing surface of the
wafers 200. This modification is applicable to the first to third
embodiments.
<<Processing Partition Walls>>
[0172] In addition, while in the embodiment described above the
processing partition walls 221 provided in the port 217 are formed
in a disc shape of diameter equivalent to the bottom plate 217c and
ceiling plate 217b of the port 217, this is not limited thereto.
The processing partition walls should be at least the size of the
wafers, and more preferably should be formed larger than the outer
circumferential side of the supports in such a way as to enclose
the port supports. In this case, instead of the diameter of the
processing partition walls of the port being increased in size, the
partition walls of the gas inlet tube 230 and/or gas exhaust tube
231 may protrude therefrom.
[0173] FIG. 28 shows a third modification in which the partition
walls of the gas inlet tube 230 and/or gas exhaust tube 231
protrude in this way.
[0174] Apart from the processing partition walls 221 and gas
introduction partition walls 228 of the port being disposed at an
equivalent height, the gas introduction partition walls 228
comprise protruding portions 228a that protrudes inward from the
inner wall surface of the reaction tube 203. In addition, apart
from the processing partition walls 221 and gas exhaust partition
walls 229 of the port 217 being disposed at an equivalent height,
the gas exhaust partition walls 229 comprises protrusions 229a that
protrudes outward in the diametric direction from the inner wall
surface of the reaction tube 203.
[0175] While the processing partition walls 221 provided in the
port 217 may be formed to extend from the outer circumferential
side of the plurality of supports 217a to the exterior, provision
in the gas introduction partition walls 228 and/or gas exhaust
partition walls 229 of protrusions 228a, 229a that protrude in the
diametric direction from the inner wall surface of the reaction
tube 203 affords a reaction tube of a simplified structure.
[0176] A third embodiment of the substrate processing apparatus of
the present invention will be hereinafter described with reference
to FIG. 29. The processing furnace shown in FIG. 29 describes a
separate mode of processing furnace to the processing furnace shown
in FIG. 22. The basic configuration of the processing furnaces is
the same, and the constituent elements of this processing furnace
correspond to those of the processing furnace of the second
embodiment described earlier with reference to FIG. 22. The
processing furnace shown in FIG. 29 differs from the processing
furnace shown in FIG. 22 in the point whereby a temperature sensor
270 serving as a temperature detector is housed in a protruding
portion 244 provided in the gas inlet tube 230 and gas exhaust tube
231. FIG. 30 is a lateral cross-sectional view of the processing
furnace prior to the temperature sensor being housed therein, FIG.
31 is a vertical cross sectional view along the line A-A' of FIG.
30, and FIG. 32 is a horizontal cross-sectional view of the
processing furnace subsequent to the temperature sensor being
housed therein.
[0177] The temperature sensor 270 serving as a temperature detector
for measuring the temperature of the wafer processing space 204 is
arranged in the reaction tube 203 of this processing furnace. The
temperature sensor extends in the direction perpendicular to the
wafer processing surface of the wafers 200 which are disposed in
plurality. A temperature control unit (see symbol 238 of FIG. 17)
is electrically connected to the temperature sensor 270. The
temperature control unit is configured to control zones of the
heater 206 zonally divided in the longitudinal direction. The
temperature control unit is configured to execute control at a
desired timing based on the current load to the heater 206 being
adjusted in accordance with temperature information detected by the
temperature sensor 270 to establish the desired temperature of the
temperature of the wafer processing space 204.
[0178] In addition, a protruding portion 244 that protrudes inward
in the diametric direction from the inner wall surface of the
reaction tube 203 is provided in at least the upper end and lower
end of the gas inlet tube 230 and gas exhaust tube 231. In the
example illustrated in FIG. 30 and FIG. 31, this protruding portion
244 is configured from a ring 244a integrally provided along the
inner wall surface of the reaction tube 203. This ring 244a is
provided not only in the upper end and lower end of the gas inlet
tube 230 and gas exhaust tube 231 but also the center portion
thereof. These rings 244a are disposed in such a way as to link the
gas introduction partition walls 228 of the gas introduction
partition portions including the upper end and lower end of the gas
inlet tube 230 and the gas exhaust partition walls 229 of the gas
exhaust partition portions including the upper end and lower end of
the gas exhaust tube 231 correspondent thereto in the horizontal
direction in the same plane.
[0179] In addition, a plurality of notched portions 252 for housing
temperature sensors 270 for detecting the temperature of the
processing chamber 201 are provided in an equivalent position in
the circumferential direction in the rings 244a in a direction
perpendicular to the processing surface of the wafers. In such a
way as to ensure the temperature sensors housed in the notched
portions 252 do not obstruct the gas flow, the plurality of notched
portions 252 are provided in a plurality of areas excluding
positions along a center line between the gas inlet tube 230 and
gas exhaust tube 231.
[0180] As shown in FIG. 32, the plurality of temperature sensors
270 are housed in the notched portions 252 in an equivalent
position in the perpendicular direction in the plurality of rings
244a provided in the vertical direction.
[0181] In the processing furnace pertaining to the third embodiment
described above, rings 244a that protrude inward from the inner
side wall of the reaction tube 203 are provided in partition
portions, these rings 244a being uniformly disposed in the
perpendicular direction of the reaction tube 203. Accordingly, gas
introduced through the gas spouting ports 212 into the reaction
tube 203 flows uniformly to the wafers 200. In addition, because
the rings 244a protrude inward of the reaction tube 203 to occupy a
portion of an unnecessary flow space 215 between the wafers 200 and
the reaction tube 203, this unnecessary flow space 215 is reduced
and unnecessary gas flow into and out of the partitions is
suppressed by the rings 244a. Accordingly, an introduced gas flow
rate of appropriate flow rate for film formation is
established.
[0182] Furthermore, because the rings 244a comprise the notched
portions 252 and the temperature sensors 270 are housable in these
notched portions 252, tilt and positional displacement of the
temperature sensors 270 can be prevented, and the reproducibility
of the position in which the temperature sensor is arranged is
improved. Accordingly, the temperature can be accurately detected
by the temperature sensors 270.
[0183] The gas spouting ports 212 for spouting gas from the gas
inlet tube 230 into the processing chamber 201 of the embodiment
described above are provided in a slit form. The slit is provided
so as to straddle at least of plurality of wafers 200 in the
perpendicular direction to the wafer processing surface. It is
clear that the gas flow conditions and the gas temperature
distribution and so on are altered by the ratio of the length,
width and breadth of the gas spouting port 212 and the ratio of the
width of the gas spouting port 212 to the length of the gas inlet
tube 230. Accordingly, the optimum slit formed gas spouting port
212 mode is preferably able to be specified. Thereupon, a
simulation of gas flow within a reaction tube using the shape of
the gas spouting port 212 as a parameter was conducted with a view
to specifying the optimum slit formed gas spouting port 212
mode.
[0184] FIG. 33 is a simulation model diagram, and FIGS. 34 and 35
are explanatory diagrams of the simulation results thereof.
[0185] The model shown in FIG. 33 constitutes a reaction tube model
based on extraction of a single gas introduction partition (for
example 230a) and gas exhaust partition (for example 231a) alone
from the gas inlet tube 230 and gas exhaust tube 231. A slit formed
gas spouting port 212 and gas exhaust port 213 are disposed in the
gas introduction partition portion 230a and gas exhaust partition
portion 231a so as to straddle eight wafers 200. Two gas inlet
tubes 214 are connected to the gas introduction partition portion
230a. The distance between the wafers 200 and the inner wall of the
reaction tube 203 is 5 mm, and the height of the side of the
reaction tube 203 in which the gas introduction partition portion
230a and gas exhaust partition portion 231a are provided is fixed
to a height b=90 mm. Dimensions a and c are used as parameters.
Dimension a denotes either the inner lateral width of the gas inlet
tube 230 or the gas exhaust tube 231, or the lateral width of the
gas spouting port 212 or lateral width of the gas exhaust port 213,
while the dimension c denotes the length of the gas inlet tube
230.
[0186] FIG. 34 and FIG. 35 are side cross-sectional views of the
gas flow velocity results taken at the center portion in the
vertical direction (height 45 mm from bottom) of the reaction tube
203. The gas flow velocity is displayed using a Dithering method.
As illustrated in FIG. 35 serving as an example thereof, of the
plurality of zones indicated by this Dithering method, the nearer
the zone to the darker zone B the faster the gas flow velocity, the
grey colored zones G1, G2, G3, G4 of different shades indicating a
slowing of gas flow velocity toward the wall of the reaction tube
(B>G1>G2>G3>G4). The gas flow velocity is scalar
displayed.
[0187] FIG. 34 is a diagram of simulation results obtained for
processing a 300 mm diameter wafer. The gas flow rate supplied from
each of two pipes was 0.5 L/min, and the gas pressure of the gas
exhausted through the gas exhaust tubes was 30 Pa.
[0188] In FIG. 34A, a length of both the gas inlet tube and the gas
exhaust tube of 190 mm, and an inner width of the gas inlet tube
and gas exhaust tube and a width of the gas spouting port and gas
exhaust port of 20 mm was adopted with respect to the 300 mm wafer.
In other words, the width of the gas spouting port and the gas
exhaust port was 1/15 the wafer diameter.
[0189] In this mode, the dark-colored section corresponds to the
gas inlet tube, the gas exhaust tube and the wafer center. In other
words, the gas spouted from the gas spouting port passes across the
wafer center and arrives at the gas exhaust tube at a flow velocity
equivalent to the flow velocity at which it flows through the gas
inlet tube.
[0190] That is to say, taking the inner width of the gas inlet tube
and the gas exhaust tube and a width of the gas spouting port and
gas exhaust port as being 1/15 the wafer diameter, the gas flow is
more readily able to be generated as a laminar flow in one
direction, and the amount of gas passing across the wafers can be
made uniform. Accordingly, a gas of uniform density and velocity
can be fed across the wafers, and the wafer in-plane interwafer
film thickness uniformity improved. In addition, the gas can be
supplied from the upstream tip-end portion of the gas inlet tube to
the wafer without a drop in the gas flow velocity occurring.
[0191] In FIG. 34B, a length of both the gas inlet tube and the gas
exhaust tube of 190 mm, and an inner width of the gas inlet tube
and gas exhaust tube and a width of the gas spouting port and gas
exhaust port of 100 mm was adopted with respect to the 300 mm
wafer. In other words, the width of the gas spouting port and the
gas exhaust port was 1/3 the wafer diameter.
[0192] In this mode as well, similarly to FIG. 34A, and even though
the range of the dark zone region is less than in FIG. 34A, the
dark-colored section corresponds to the gas inlet tube, the gas
exhaust tube and the wafer center. In other words, the gas spouted
from the gas spouting port passes across the wafer center and
reaches the gas exhaust tube at a flow velocity equivalent to the
flow velocity at which it flows through the gas inlet tube.
[0193] In FIG. 34C, a length of both the gas inlet tube and the gas
exhaust tube of 190 mm, and an inner width of the gas inlet tube
and gas exhaust tube and a width of the gas spouting port and gas
exhaust port of 150 mm was adopted with respect to the 300 mm
wafer. In other words, the width of the gas spouting port and the
gas exhaust port was 1/2 the wafer diameter.
[0194] In this mode as well, similarly to FIGS. 34A and 34B, and
even though the range of the dark zone region is less than in FIG.
34A, the dark-colored section corresponds to the gas inlet tube,
the gas exhaust tube and the wafer center. In other words, the gas
spouted from the gas spouting port passes across the wafer center
and reaches the gas exhaust tube at a flow velocity equivalent to
the flow velocity at which it flows through the gas inlet tube.
[0195] In FIG. 34D, a length of both the gas inlet tube and the gas
exhaust tube is 190 mm, and an inner width of the gas inlet tube
and gas exhaust tube and a width of the gas spouting port and gas
exhaust port of 200 mm was adopted with respect to the 300 mm
wafer. In other words, the width of the gas spouting port and gas
exhaust port was 2/3 the wafer diameter.
[0196] In this mode, the dark-colored section does not correspond
with the wafer center. In other words, the gas spouted from the gas
spouting port passes across the wafer center at a lower flow
velocity to the flow velocity at which it flows in the gas inlet
tube. For this reason, compared to FIGS. 34A to 34C described
above, the desired film thickness uniformity is much more difficult
to ensure.
[0197] In FIG. 34E, a length of both the gas inlet tube and the gas
exhaust tube of 285 mm, and an inner width of the gas inlet tube
and gas exhaust tube and a width of the gas spouting port and gas
exhaust port of 20 mm was adopted with respect to the 300 mm
wafer.
[0198] In this mode as well, similarly to FIG. 34A, and even though
the range of the dark zone region is less than in FIG. 34A, the
dark-colored section corresponds to the gas inlet tube, the gas
exhaust tube and the wafer center. In other words, the gas spouted
from the gas spouting port passes across the wafer center and
reaches the gas exhaust tube at a flow velocity equivalent to the
flow velocity at which it flows through the gas inlet tube.
[0199] In FIG. 34F, a length of both the gas inlet tube and the gas
exhaust tube of 95 mm, and an inner width of the gas inlet tube and
gas exhaust tube and a width of the gas spouting port and gas
exhaust port of 20 mm with respect to the 300 mm wafer was
adopted.
[0200] In this mode as well, similarly to FIG. 34A, and even though
the range of the dark zone region is less than in FIG. 34A, the
dark-colored section corresponds to the gas inlet tube, the gas
exhaust tube and the wafer center. In other words, the gas spouted
from the gas spouting port passes across the wafer center and
reaches the gas exhaust tube at a flow velocity equivalent to the
flow velocity at which it flows through the gas inlet tube.
[0201] In FIG. 34G, a length of both the gas inlet tube and the gas
exhaust tube of 190 mm, and an inner width of the gas inlet tube
and width of the gas introduction orifice of 150 mm with respect to
the 300 mm wafer was adopted. In addition, an inner width of the
gas exhaust tube and the gas exhaust port of 20 mm was adopted.
[0202] In this mode as well, similarly to FIG. 34A, and even though
the range of the dark zone region is less than in FIG. 34A, the
dark-colored section corresponds to the gas inlet tube, the gas
exhaust tube and the wafer center. In other words, the gas spouted
from the gas spouting port passes across the wafer center and
reaches the gas exhaust tube at a flow velocity equivalent to the
flow velocity at which it flows through the gas inlet tube.
[0203] In FIG. 34H, a length of both the gas inlet tube and the gas
exhaust tube of 190 mm, and an inner width of the gas inlet tube
and gas introduction orifice of 20 mm with respect to the 300 mm
wafer was adopted. In addition, an inner width of the gas exhaust
tube and width of the gas exhaust port of 150 mm was adopted.
[0204] In this mode as well, similarly to FIG. 34A, and even though
the range of the dark zone region is less than in FIG. 34A, the
dark-colored section corresponds to the gas inlet tube, the gas
exhaust tube and the wafer center. In other words, the gas spouted
from the gas spouting port passes across the wafer center and
reaches the gas exhaust tube at a flow velocity equivalent to the
flow velocity at which it flows through the gas inlet tube.
[0205] FIG. 35 is a diagram of simulation results obtained for
processing a 450 mm diameter wafer. The gas flow rate from the
pipes was set at 1.125 L/min or approximately 2.25 times the gas
flow rate employed for processing the 300 mm wafer, and the gas
pressure of the gas exhausted from the gas exhaust tube was set to
a pressure equivalent to the pressure employed for processing the
300 mm wafer of 30 Pa.
[0206] In FIG. 35A, a length of both the gas inlet tube and the gas
exhaust tube of 285 mm, and an inner width of the gas inlet tube
and gas exhaust tube and width of the gas spouting port and gas
exhaust port of 30 mm with respect to the 450 mm wafer was adopted.
In other words, the width of the gas spouting port and the gas
exhaust port was 1/15 the wafer diameter.
[0207] In this mode, the dark-colored section corresponds to the
gas inlet tube, the gas exhaust tube and the wafer center. In other
words, the gas spouted from the gas spouting port passes across the
wafer center and reaches the gas exhaust tube at a flow velocity
equivalent to the flow velocity at which it flows through the gas
inlet tube.
[0208] In FIG. 35B, a length of both the gas inlet tube and the gas
exhaust tube of 285 mm, and an inner width of the gas inlet tube
and gas exhaust tube and a width of the gas spouting port and gas
exhaust port of 225 mm with respect to the 450 mm wafer was
adopted. In other words, the width of the gas spouting port and gas
exhaust port was set to 1/2 the wafer diameter.
[0209] In this mode as well, similarly to FIG. 34A, and even though
the range of the dark zone region is less than in FIG. 34A, the
dark-colored section corresponds to the gas inlet tube, the gas
exhaust tube and the wafer center. In other words, the gas spouted
from the gas spouting port passes across the wafer center and
reaches the gas exhaust tube at a flow velocity equivalent to the
flow velocity at which it flows through the gas inlet tube.
[0210] Here, it is preferable that the minimum size at which a gas
pipe can be connected of 6.35 mm be adopted as the minimum width of
the gas inlet tube.
[0211] The following can be inferred from the simulation results
described above.
[0212] The lateral width a of the gas spouting port is preferably
less than the wafer diameter. If this is the case, the gas can be
supplied from the upstream side tip-end portion of the gas inlet
tube to the wafer without a drop in gas flow velocity
occurring.
[0213] Taking the lateral width of the gas spouting port as a and
the height thereof as b, it is preferable that a<b. Assuming
a<b, gas can be supplied from the upstream tip-end portion of
the gas inlet tube to the wafer without a drop in gas flow velocity
occurring. In addition, assuming a change in the height b of the
gas spouting port for processing a plurality of wafers, it is
preferable from the viewpoint of pressure resistance that the width
a thereof is reduced.
[0214] Taking the lateral width of the gas spouting port as a and
the length of the gas spouting port as c, it is preferable that
a<c. Attempts to impart as large an amount of heat as possible
in the pre-heating range under fixed heater (heating device)
temperature, gas pressure and gas flow rate conditions necessitate
an increase in the length c in the direction in which the gas
advances with respect to the heating source, and the width a should
be reduced by that amount.
[0215] It is preferable that the lateral width of the gas spouting
port and/or gas exhaust port is no more than 1/2 the wafer
diameter, and more preferably that the lateral width of the gas
spouting port and/or gas exhaust port is no more than 1/3 the wafer
diameter, and even more preferably that the lateral width of the
gas spouting port and/or gas exhaust port is no more than 1/15 the
wafer diameter.
[0216] Preferred modes of the present invention will be hereinafter
described.
[0217] A first mode of the substrate processing apparatus provides
a substrate processing apparatus comprising: a reaction tube having
in an interior thereof a processing chamber in which a plurality of
substrates disposed in a direction perpendicular to a substrate
processing surface can be processed; and a heating device provided
to surround an outer circumference of the reaction tube, a gas
inlet tube being provided on a side face of the above-mentioned
reaction tube in a region for processing a substrate inside the
abovementioned reaction tube, so as to reach at least an outside of
the abovementioned heating device, and a gas spouting port being
disposed in this gas inlet tube in a slit form so as to straddle at
least a plurality of the substrates in a direction perpendicular to
the abovementioned substrate processing surface, for spouting gas
from the abovementioned gas inlet tube into the abovementioned
processing chamber.
[0218] Because a gas inlet tube is disposed on a side face of the
abovementioned reaction tube in a region for processing a substrate
inside the abovementioned reaction tube, the gas flow supplied from
the gas inlet tube into the reaction tube forms a side flow and, as
a result, the substrate processing efficiency is improved.
[0219] Because a gas spouting port being disposed in this gas inlet
tube in a slit form so as to straddle at least a plurality of the
substrates in a direction perpendicular to the abovementioned
substrate processing surface for spouting gas from the
abovementioned gas inlet tube into the abovementioned processing
chamber, the amount of gas flowing across the substrates is
improved, and the in-plane and intersubstrate film thickness
uniformity improved.
[0220] It is preferable in this first mode that the abovementioned
gas inlet tube comprise a plurality of gas introduction partition
portions partitioned in a direction perpendicular to the processing
surface of the abovementioned substrates, and that the
abovementioned gas spouting port be formed in each of the
abovementioned gas introduction partition portions.
[0221] When the gas inlet tube comprises a plurality of gas
introduction partition portions partitioned in a direction
perpendicular to the processing surface of the abovementioned
substrates and the abovementioned gas spouting port is formed in
each of the gas introduction partition portions, a reliable and
uniform flow of gas across the substrates is produced, and a
loading effect can be prevented. In addition, because an
unnecessary gas flow into and out of the partitions is suppressed,
the proper usage gas flow rate for processing can be obtained.
Accordingly, the in-plane and intersubstrate film thickness
uniformity of a large number of substrates on which a film is being
simultaneously formed is improved.
[0222] In addition, the abovementioned gas spouting port is
preferably formed one for each of the abovementioned gas
introduction partition portions. Because a single introduction flow
rate can be spouted from a single gas spouting port by formation of
a single gas spouting port in each of the gas introduction
partition portions in this way, gas of a state having equivalent
heat quantity and in which there is no drop in gas flow velocity at
the center portion of the substrates arrives at the center of the
substrates.
[0223] In addition, the opening area of the above-mentioned gas
introduction orifice is preferably equivalent to the
cross-sectional area of the abovementioned gas introduction
partition portion in a direction perpendicular to the
abovementioned substrate processing surface. When the opening area
of the gas introduction orifice is equivalent to the
cross-sectional area of the gas introduction partition portion in a
direction perpendicular to the substrate processing surface, gas
can be supplied more smoothly to the substrate processing
surface.
[0224] In addition, in this first mode the abovementioned gas inlet
tube is preferably formed so that a distance from at least the
abovementioned gas spouting port to an upstream tip-end portion of
the gas inlet tube is greater than a distance between two ends of
the abovementioned gas spouting port in a circumferential direction
of the substrates.
[0225] In addition, in a configuration such as this when the gas
introduction portion is provided lengthways along the side of the
reaction tube, gas can be supplied to the substrate processing
surface without drop in gas flow velocity from the upstream tip-end
portion of the gas inlet tube to the substrates.
[0226] In addition, in this first mode the abovementioned gas inlet
tube is preferably formed along an entire side along the
abovementioned substrate processing region. When the gas inlet tube
is formed along an entire side along the substrate processing
region, the substrate processing region is covered by a side
flow.
[0227] In addition, in this first mode it is preferable that a gas
exhaust tube is further provided on the side face of the reaction
tube in a region for processing a substrate inside the
abovementioned reaction tube so as to reach at least an outside of
the heating device, and that a gas exhaust port disposed is
provided in the gas exhaust tube in a slit form so as to straddle
at least a plurality of the substrates in a direction perpendicular
to the abovementioned substrate processing surface for exhausting
gas into the abovementioned gas exhaust tube from the
abovementioned processing chamber.
[0228] Because both a gas introduction and a gas exhaust side flow
are formed, when a gas exhaust tube is disposed on the side face of
the reaction tube and the gas exhaust port is provided in a slit
form in this gas exhaust tube in a direction perpendicular to the
substrate processing surface so as to straddle at least a plurality
of substrates, for exhausting gas into the gas inlet tube from the
processing chamber, the substrate processing efficiency can be
further improved. In addition, the amount of gas flowing across the
substrates can be made uniform, and the in-plane and intersubstrate
film thickness uniformity further improved.
[0229] It is preferable that the abovementioned gas inlet tube
comprise a plurality of gas introduction partition portions
partitioned in a direction perpendicular to the processing surface
of the abovementioned substrates, and that the abovementioned gas
spouting port be formed in each of the abovementioned gas
introduction partition portions.
[0230] Apart from the gas inlet tube, when the gas exhaust tube
comprises gas exhaust partition portions and a gas spouting port is
formed in each of the gas exhaust partition portions, a reliable
and uniform flow of gas across the substrates is produced, and a
loading effect can be prevented. In addition, because an
unnecessary gas flow into and out of the partitions is suppressed,
the proper usage gas flow rate for processing can be obtained.
Accordingly, the in-plane and intersubstrate film thickness
uniformity of a large number of substrates on which a film is being
simultaneously formed is improved.
[0231] It is preferable that a process gas supply portion and a
first inert gas supply portion are connected to an upstream side of
the abovementioned gas introduction partition portions, and that a
gas supply portion is further provided for, when processing the
substrates in the abovementioned reaction tube, supplying a process
gas from the process gas supply portion when the substrates are
disposed in positions opposing the gas introduction partition
portions, and supplying an inert gas from the inert gas supply
portion when no substrate is disposed in positions opposing the gas
introduction partition portions.
[0232] Because an inert gas rather than a process gas is supplied
by means of a gas control unit from the gas introduction partition
portions of the position in which there are no substrates disposed,
that attachment and accumulation of reaction product in the
reaction tube can be suppressed.
[0233] In addition, the first mode is preferably further provided
with a plasma generating device constituted from electrodes
disposed outside the processing chamber, with the abovementioned
gas inlet tube between these electrodes, for creating plasma of a
gas in the abovementioned gas inlet tube.
[0234] Because a remote plasma system can be established when a
plasma generating device constituted from electrodes disposed
externally of a processing chamber about the abovementioned gas
inlet tube for creating a plasma of a gas of the abovementioned gas
inlet tube is further provided, damage to the substrates can be
avoided, and the in-plane and intersubstrate film thickness
uniformity of a plurality of substrates on which a film is
simultaneously formed is improved.
[0235] In addition, the first mode preferably further comprises a
second inert gas supply portion for supplying an inert gas from
above the abovementioned reaction tube into the reaction tube.
[0236] When a second inert gas supply portion for supplying an
inert gas from above the reaction tube into the reaction tube is
provided, the flow of process gas above the reaction tube can be
prevented.
[0237] In addition, the first mode preferably further comprises a
third inert gas supply portion for supplying an inert gas from
below the abovementioned reaction tube into the reaction tube. When
a third inert gas supply portion for supplying an inert gas from
below the reaction tube into the reaction tube is provided, the
flow of process gas below the reaction tube can be prevented.
[0238] In addition, the first mode preferably further comprises a
gas interrupting portion above the abovementioned reaction tube.
When a gas interrupting portion is provided above the reaction
tube, the flow of process gas above the reaction tube can be
prevented.
[0239] In addition, it is preferable that a reinforcing member for
reinforcing the wall of the reaction tube and which extends in a
direction perpendicular to the processing surface of the
abovementioned substrates is further provided in the abovementioned
gas interrupting portion. When a reinforcing member is provided in
the gas interrupting portion, the pressure resistance of the
reaction tube is improved.
[0240] In addition, it is preferable that the abovementioned gas
interrupting portion is constituted from the wall of the
abovementioned reaction tube. When the gas interrupting portion is
constituted from the wall of the reaction tube, the configuration
thereof is simplified.
[0241] In addition, it is preferable that the abovementioned gas
interrupting portion is provided in the inner wall of the
abovementioned reaction tube. Provision of the gas interrupting
portion in the inner wall of the reaction tube allows for the
effective utilization of known reaction tubes.
[0242] In addition, it is preferable that protruding portions is
provided to protrude inward from an inner wall surface of the
abovementioned reaction tube at, at least, an upper and a lower end
of the abovementioned gas inlet tube and the abovementioned gas
exhaust tube comprise.
[0243] When the upper end of the gas inlet tube comprises a
protruding portion that protrudes inward from the inner wall
surface of the reaction tube, flow of the process gas supplied from
the gas inlet tube into the reaction tube above the reaction tube
ceiling plate is inhibited. In addition, when the lower end of the
gas inlet tube comprises a protruding portion that protrudes inward
from the inner wall surface of the reaction tube, flow of the
process gas supplied from the gas inlet tube into the reaction tube
below the reaction tube bottom plate is inhibited. In addition,
when both the upper end and the lower end of the gas inlet tube
comprise protruding portions that protrude inward from the inner
wall surface of the reaction tube, the structure is comparatively
more simplified than when formed in a substrate holding tool in
which substrates are disposed in plurality in a perpendicular
direction to the substrate processing surface.
[0244] In addition, it is preferable that notched portions are
provided in the same positions as in the protruding portions in a
circumferential direction with respect to a processing surface of
the substrates. The provision of notched portions in the same
positions as in the protruding portions in a circumferential
direction with respect to a processing surface of the substrates
allows for a temperature detector to be housed in these notched
portions.
[0245] In addition, it is preferable that a temperature detector
for detecting a temperature within a processing chamber is housed
in the abovementioned notched portions of the abovementioned
protruding portions. Because a temperature detector for detecting a
temperature within a processing chamber is housed in the notched
portions of the protruding portions, the reproducibility of the
positions in which the temperature detectors are provided is good,
and stable temperature detection can be performed.
[0246] In addition, a second mode thereof provides a substrate
processing apparatus comprising a cylindrical reaction tube having
in an interior thereof a processing chamber in which a plurality of
substrates disposed in a direction perpendicular to a substrate
processing surface can be processed and a cylindrical heating
device provided to surround an outer circumference of the reaction
tube, a gas inlet tube and a gas exhaust tube being disposed on a
side face of the abovementioned reaction tube so as to reach at
least an outside of the abovementioned heating device.
[0247] Because both the reaction tube and the heating device are
cylindrical in shape, improved uniformity of heating is achieved,
and the substrate processing efficiency can be further improved. In
addition, because the gas inlet tube and the gas exhaust tube are
disposed on the side face of the reaction tube to reach at least
the outside of the heating device, the diameter of the reaction
tube is reduced, and a more reliable and ready flow of the gas
across the substrates is produced. Accordingly, the in-plane and
intersubstrate film thickness uniformity of a large number of
substrates on which a film is being simultaneously formed is
improved.
[0248] In addition, a third mode thereof provides a substrate
processing apparatus comprising: a cylindrical reaction tube having
in an interior thereof a processing chamber in which a plurality of
substrates disposed in a direction perpendicular to a substrate
processing surface can be processed; and a cylindrical heating
device provided to surround an outer circumference of the reaction
tube,
[0249] a gas inlet tube being provided on a side face the
abovementioned reaction tube in a region for processing a substrate
inside the abovementioned reaction tube so as to reach at least the
outside of the abovementioned heating device, and
[0250] a gas spouting port being disposed in this gas inlet tube in
a slit form so as to straddle at least a plurality of substrates in
a direction perpendicular to the abovementioned substrate, for
spouting gas from the gas inlet tube into the abovementioned
processing chamber.
[0251] Because a gas inlet tube is disposed on a side face of the
reaction tube in the region for processing the substrate inside the
reaction, the gas flow supplied from the gas inlet tube into the
reaction tube is formed as a side flow and, as a result, the
substrate processing efficiency is improved.
[0252] Because a gas spouting port is disposed in the gas inlet
tube in a slit form so as to straddle at least a plurality of the
substrates in a direction perpendicular to the substrate processing
surface for spouting gas from the gas inlet tube into the
processing chamber, the amount of gas flowing across the substrates
can be made uniform, and the in-plane and intersubstrate film
thickness uniformity improved. In addition, because both the
reaction tube and the heating device are cylindrical in shape,
improved uniformity of heating is achieved, and the substrate
processing efficiency can be further improved.
[0253] In addition, a method of manufacturing a semiconductor
device for processing in use of the substrate processing apparatus
of the first mode provides a method of manufacturing a
semiconductor device comprising the steps of: conveying substrates
into the abovementioned reaction tube; processing the substrates by
introducing a gas from the abovementioned gas spouting port across
the substrates within the abovementioned reaction tube while
maintaining the gas flow velocity in the abovementioned gas inlet
tube, and heating the abovementioned reaction tube by means of the
abovementioned heating device; and conveying substrates out of the
abovementioned reaction tube. Accordingly, the amount of gas
flowing across the substrates can be made uniform, a uniform
in-plane gas density and gas velocity can be supplied to the
substrates, and the in-plane and intersubstrate film thickness
uniformity improved.
[0254] In addition, a fourth mode provides a reaction vessel in
cylindrical shape having in an interior thereof a processing
chamber in which a plurality of substrates disposed in a direction
perpendicular to a substrate processing surface can be processed, a
gas inlet tube and a gas exhaust tube being provided on a side face
of the abovementioned reaction tube in a region for processing the
substrate inside the reaction tube, the gas inlet tube and the gas
exhaust tube extending in a direction perpendicular to the side
face of the reaction tube, and a gas spouting port being disposed
in at least the gas inlet tube in a slit form so as to straddle at
least a plurality of the substrates in a direction perpendicular to
said substrate processing surface, for spouting gas from the
abovementioned gas inlet tube into the abovementioned processing
chamber.
[0255] Because the reaction tube is cylindrical in shape, the
uniformity of the heating is improved, and the substrate processing
efficiency is further improved. In addition, because a gas inlet
tube and a gas exhaust tube are provided on the side face of the
reaction tube, the diameter of the reaction tube is reduced, and
the gas flows more readily and reliably across the substrates.
Accordingly, the in-plane and intersubstrate film thickness
uniformity of a plurality of substrates on which a film is
simultaneously formed is improved.
[0256] In addition, because a gas spouting port is disposed in at
least the gas inlet tube in a slit form so as to straddle at least
a plurality of substrates in a direction perpendicular to said
substrate processing surface, for spouting gas from the gas inlet
tube into the processing chamber, the amount of gas flowing across
the substrates can be made uniform, and the in-plane and
intersubstrate film thickness uniformity improved.
[0257] In addition, it is preferable that in the first mode the
width of the abovementioned spouting port in a direction horizontal
to the abovementioned substrate processing surface is formed to be
no more than 1/2 a diameter of the abovementioned substrates. The
adoption of this configuration allows the gas to be spouted from
the gas spouting port to pass across the center of the substrates
at a velocity equivalent to the velocity at which the gas flows
through the gas inlet tube.
[0258] In addition, it is preferable that in the first mode the
width of the abovementioned spouting port in a direction horizontal
to the abovementioned substrate processing surface is formed to be
no more than 1/15 a diameter of the abovementioned substrates. The
adoption of this configuration ensures the amount of gas flowing
across the substrates is made uniform, a uniform in-plane gas
density and gas velocity is supplied to the substrates, and the
in-plane and intersubstrate film thickness uniformity is
improved.
[0259] In addition, a fifth mode provides a method of manufacturing
a semiconductor device comprising the steps of: conveying a
plurality of substrates disposed in a direction perpendicular to
the substrate processing surface into the processing chamber; and
processing the substrates by, in a substrate processing based on a
gas flowing from a gas inlet tube across substrates being rotated
in said processing chamber, causing the gas to arrive at a center
portion of the abovementioned substrate processing surface of said
substrates while maintaining the gas flow velocity of the
abovementioned gas inlet tube. Accordingly, the amount of gas
flowing across the substrates can be made uniform, a uniform
in-plane gas density and gas velocity can be supplied to the
substrates, and the in-plane and intersubstrate film thickness
uniformity improved.
Description of an Embodiment in which the Processing Furnace of
these Embodiments has Application
[0260] FIG. 17 is a schematic cross-sectional diagram of the
processing furnace 202 of one embodiment of a substrate processing
apparatus preferably employed in the embodiments of the present
invention. The basic constituent elements of the processing furnace
are the same as the corresponding constituent element of the
processing furnace of the first embodiment described with reference
to FIG. 1 and, accordingly, to avoid a repetition of the
description thereof, the description given hereinafter pertains
chiefly to the gas introduction system/gas exhaust system, the
heater system and the control system thereof.
<<Gas Introduction System>>
[0261] Process gas supply portions 249a to 249h for supplying a
process gas such as a film formation gas and first inert gas supply
portions 250a to 250h for supplying a first inert gas such as an
N.sub.2 gas are connected by way of MFC (mass flow control units)
241a to 241h serving as gas flow rate control devices to the
upstream side of each of a plurality of gas introduction partition
portions 230a to 230h of a gas inlet tube 230. A gas flow rate
control unit 235 is electrically connected to the MFC 241a to
241h.
[0262] The processing of wafers 200 within a reaction tube 203
involves supply of a process gas from the process gas supply
portions 249a to 249h when the wafers 200 are disposed in a
position opposing the gas introduction partition portions 230a to
230h and supply of an inert gas supplied from the first inert gas
supply portions 250a to 250h when there are no wafers 200 disposed
opposing the gas introduction partition portions 230a to 230h by
the MFC 241a to 241h. The previously described gas control unit is
constituted from the MFC 241a to 241h.
<<Gas Discharge System>>
[0263] Pressure sensors 245a to 245h serving as pressure detectors
and, by way of pressure adjusting devices 242a to 242h, vacuum
exhaust devices 246a to 246h such as vacuum pumps configured to
vacuum exhaust the pressure of a processing chamber 201 to a
predetermined pressure (vacuum degree) are connected to the
downstream side of each of a plurality of gas exhaust partition
portions 231a to 231h of a gas exhaust tube 231. A pressure control
unit 236 is electrically connected to the pressure adjusting
devices 242a to 242h and the pressure sensors 245a to 245h, the
pressure control unit 236 being configured so that the pressure in
the processing chamber 201 is controlled by the pressure adjusting
devices 242a to 242h in response to the pressure detected by the
pressure sensors 245a to 245h at a predetermined timing.
<<Heater System>>
[0264] A heat-insulating body 260 of a heater 206 is constituted
from a cylindrical side wall heat-insulating member 264, and a
circular ceiling heat-insulating member 265 for closing an upper
part of the side wall heat-insulating member 264.
[0265] A heater wire 266a serving as a first heat-insulating body
266 is provided between the side wall heat-insulating member 264
and the reaction tube 203. The heater wire 266a describes a zigzag
shape and, similarly to the prior art, is provided in a ring shape
that traces the inner wall of zones of the side wall
heat-insulating member 264 which is zonally divided in the
longitudinal direction.
[0266] A gas inlet tube side wall heat-insulating body 267a serving
as a second heat-insulating body 267 is provided between a gas
inlet tube notched portion 261a and the gas inlet tube 230. The gas
inlet tube side wall heat-insulating body 267a is provided to trace
the inner side wall of the gas inlet tube notched portion 261a.
[0267] A gas inlet tube side wall heat-insulating body 267a (sic)
serving as a third heat-insulating body 268 is provided between a
gas exhaust tube notched portion 262a and the gas exhaust tube 231.
The gas exhaust tube side wall heat-insulating body 268a is
provided to trace the inner side wall of the gas exhaust tube
notched portion 262a.
[0268] The gas inlet tube side wall heat-insulating body 267a and
gas exhaust tube side wall heat-insulating body 268a are provided
to cover at least inner wall notched portions in the vicinity of
the gas inlet tube 230 and the gas exhaust tube 231. The provision
of these side wall heating members in the two opposing inner side
walls of the gas inlet tube notched portion 261a and gas exhaust
tube notched portion 262a rather that a single side wall is
preferred, and the provision thereof in the inner upper wall of the
gas inlet tube notched portion 261a or gas exhaust tube notched
portion 262a is more preferred.
[0269] When the gas inlet tube side wall heat-insulating body 267a
and gas exhaust tube side wall heat-insulating body 268a are
preferably provided to span the zonally divided zones of the heater
wire 266a, a more precise controllability is produced. A power
supply for supplying power to the gas inlet tube side wall
heat-insulating body 267a and the gas exhaust tube side wall
heat-insulating body 268a provided as a separate power supply to
the power supply for supplying power to the heater wire 266a.
<<Control System>>
[0270] The processing furnace control system executes the
temperature control and other controls described hereinafter.
<<Temperature Control>>
[0271] A temperature sensor 263 serving as a temperature detector
is disposed in the vicinity of the outer side of the reaction tube
203. A temperature control unit 238 electrically connected to the
heater 206 and the temperature sensor 263 is configured to control
the temperature in the processing chamber 201 at a predetermined
timing to produce a desired temperature distribution by adjusting
the current flowing to the heater 206 in accordance with
temperature information detected by the temperature sensor 263. The
temperature sensor 263 may employ a temperature sensor 270 as
described in the third embodiment.
[0272] In addition, a temperature sensor 269 serving as a
temperature detector is disposed in the gas inlet tube notched
portion 261a (see FIG. 2 and FIG. 6). The temperature control unit
238 electrically connected to the gas inlet tube side wall
heat-insulating body 267a and the temperature sensor is configured
to control the temperature in the gas inlet tube 230 at a
predetermined timing to produce a desired temperature distribution
by adjusting the current flowing to the gas inlet tube side wall
heat-insulating body 267a in accordance with temperature
information detected by the temperature sensor.
[0273] Furthermore, a temperature sensor 270 serving as a
temperature detector is disposed in the gas exhaust tube notched
portion 262a (see FIG. 2 and FIG. 6). The temperature control unit
238 electrically connected to the gas exhaust tube side wall
heat-insulating body 268a and the temperature sensor is configured
to control the temperature in the gas exhaust tube 231 at a
predetermined timing to produce a desired temperature distribution
by adjusting the current flowing to the gas exhaust tube side wall
heat-insulating body 268a in accordance with temperature
information detected by the temperature sensor.
[0274] The temperature control unit 238 is configured to control
each of the above-described heater wire 266a, gas inlet tube side
wall heat-insulating body 267a and gas exhaust tube side wall
heat-insulating body 268a using different systems.
[0275] A drive control unit 237 electrically connected to a rotary
mechanism 254 and port elevator is configured to execute a control
for implementing desired operations at desired timings.
<<Other Controls>>
[0276] The gas flow rate control unit 235, pressure control unit
236, drive control unit 237 and temperature control unit 238 are
electrically connected to a main control unit 239 constituted
additionally from an operating unit and an input/output unit for
controlling the substrate processing apparatus in its entirety. The
gas flow rate control unit 235, pressure control unit 236, drive
control unit 237, temperature control unit 238 and main control
unit 239 are configured as a controller 240.
[0277] The processing furnace 202 of the embodiments is configured
as described above.
Example Processing Conditions
[0278] As an example of the processing conditions for processing
wafers in the processing furnace of the embodiments for the film
formation of a Si.sub.3N.sub.4 film includes a processing pressure
of 30 Pa, the employment of dichlorosilane gas (SiH.sub.2Cl.sub.2)
and ammonia gas (NH.sub.3) as the gas types, and a gas supply flow
rate to the partition portions of SiH.sub.2Cl.sub.2 0.1 sccm and
NH.sub.3 0.5 sccm may be employed. The conditions additionally
include a processing temperature in the reaction tube 203 heated by
the heater wire 266a of 760.degree. C., a temperature in the gas
inlet tube 230 heated by the gas inlet tube side wall heating body
267a of 300.degree. C., and a temperature of the gas exhaust tube
231 heated by the gas exhaust tube side wall heating body 268a of
300.degree. C.
[0279] The wafer processing is administered p with each of these
respective processing conditions maintained to a constant value
within a respective range thereof.
* * * * *