U.S. patent application number 14/530144 was filed with the patent office on 2015-02-19 for substrate processing apparatus and semiconductor device producing method.
This patent application is currently assigned to HITACHI KOKUSAI ELECTRIC INC.. The applicant listed for this patent is HITACHI KOKUSAI ELECTRIC INC.. Invention is credited to Masanori SAKAI, Tomohiro YOSHIMURA.
Application Number | 20150050818 14/530144 |
Document ID | / |
Family ID | 34975858 |
Filed Date | 2015-02-19 |
United States Patent
Application |
20150050818 |
Kind Code |
A1 |
SAKAI; Masanori ; et
al. |
February 19, 2015 |
SUBSTRATE PROCESSING APPARATUS AND SEMICONDUCTOR DEVICE PRODUCING
METHOD
Abstract
Disclosed is a substrate processing apparatus, including: a
processing chamber for processing a substrate; a substrate rotating
mechanism for rotating the substrate; a gas supply unit for
supplying gas to the substrate, at least two kinds of gases A and B
being alternately supplied a plurality of times to form a desired
film on the substrate; and a controller for controlling a rotation
period of the substrate or a gas supply period defined as a time
period between an instant when the gas A is made to flow and an
instant when the gas A is made to flow next time such that the
rotation period and the gas supply period are not brought into
synchronization with each other at least while the alternate gas
supply is carried out predetermined times.
Inventors: |
SAKAI; Masanori; (Toyama,
JP) ; YOSHIMURA; Tomohiro; (Toyama, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HITACHI KOKUSAI ELECTRIC INC. |
TOKYO |
|
JP |
|
|
Assignee: |
HITACHI KOKUSAI ELECTRIC
INC.
TOKYO
JP
|
Family ID: |
34975858 |
Appl. No.: |
14/530144 |
Filed: |
October 31, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13104626 |
May 10, 2011 |
8901011 |
|
|
14530144 |
|
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|
10592348 |
Oct 11, 2007 |
7950348 |
|
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PCT/JP2005/004299 |
Mar 11, 2005 |
|
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13104626 |
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Current U.S.
Class: |
438/791 ;
118/700 |
Current CPC
Class: |
C23C 16/45525 20130101;
H01L 21/67253 20130101; C23C 16/345 20130101; C23C 16/4584
20130101; C23C 16/52 20130101; C23C 16/45546 20130101; H01L 21/0217
20130101; C23C 16/45544 20130101; C23C 16/45563 20130101; H01L
21/67109 20130101; H01L 21/0228 20130101; H01L 21/67017 20130101;
C23C 16/509 20130101 |
Class at
Publication: |
438/791 ;
118/700 |
International
Class: |
H01L 21/02 20060101
H01L021/02; C23C 16/458 20060101 C23C016/458; C23C 16/455 20060101
C23C016/455; C23C 16/52 20060101 C23C016/52 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 12, 2004 |
JP |
2004-070136 |
Claims
1. A method of manufacturing a semiconductor device, comprising:
providing a substrate; and processing the substrate with the
substrate being rotated and processing gas being periodically
supplied to the substrate, wherein a supply cycle of the processing
gas and a rotation period of the substrate do not come into
synchronization with each other at least during a predetermined
period in the processing of the substrate.
2. The method according to claim 1, wherein the processing gas
includes at least two types of gases.
3. The method according to claim 1, wherein the processing gas
includes first processing gas and second processing gas.
4. The method according to claim 3, wherein the processing of the
substrate includes alternately supplying the first processing gas
and the second processing gas to the substrate.
5. The method according to claim 3, wherein the processing of the
substrate includes performing a cycle a predetermined number of
times, the cycle including: supplying the first processing gas to
the substrate; and supplying the second processing gas to the
substrate.
6. The method according to claim 3, wherein the processing of the
substrate includes performing a cycle a predetermined number of
times, the cycle including: supplying the first processing gas to
the substrate; removing the first processing gas from a space in
which the substrate exists; supplying the second processing gas to
the substrate; and removing the second processing gas from the
space in which the substrate exists.
7. The method according to claim 1, wherein the processing gas is
supplied to the substrate from a side of the substrate.
8. The method according to claim 1, wherein the processing gas is
supplied to a center side of the substrate from a peripheral side
of the substrate.
9. A method of manufacturing a semiconductor device, comprising:
providing a substrate; and processing the substrate by performing a
cycle a predetermined number of times with the substrate being
rotated, the cycle including: supplying first processing gas to the
substrate; and supplying second processing gas to the substrate,
wherein a supply cycle of at least one of the first processing gas
or the second processing gas and a rotation period of the substrate
do not come into synchronization with each other at least during a
predetermined period in the processing of the substrate
10. A substrate processing apparatus, comprising: a processing
chamber configured to accommodate a substrate; a rotating mechanism
configured to hold and rotate the substrate in the processing
chamber; a gas supply unit configured to supply processing gas to
the substrate in the processing chamber; and a controller
configured to control the rotating mechanism and the gas supply
unit such that the substrate is processed with the substrate being
rotated and processing gas being periodically supplied to the
substrate, and a supply cycle of the processing gas and a rotation
period of the substrate do not come into synchronization with each
other at least during a predetermined period in the processing of
the substrate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of copending application
Ser. No. 13/104,626, filed on May 10, 2011, which is a Divisional
of Application Ser. No. 10/592,348 (U.S. Pat. No. 7,950,348), filed
on Oct. 11, 2007, which was filed as PCT International Application
No. PCT/JP2005/004299 on Mar. 11, 2005, which claims the benefit
under 35 U.S.C. .sctn.119(a) to Patent Application No. 2004-070136,
filed in Japan on Mar. 12, 2004, all of which are hereby expressly
incorporated by reference into the present application.
TECHNICAL FIELD
[0002] The present invention relates to a substrate processing
apparatus and a producing method of a semiconductor device, and
more particularly, to a substrate processing apparatus and a
producing method of a semiconductor device which process a
semiconductor substrate using gas.
[0003] A general CVD apparatus forms a film on a substrate by
keeping reaction gas flowing for a given time. At that time, the
substrate is rotated in some cases to eliminate influence of a
distance (short or long) from a gas supply port and to enhance the
consistency of film thickness over the entire surface of the
substrate. In such a case, generally, the film forming time is
sufficiently long as compared with the rotation period, and the
substrate is rotated many times when the film is formed because gas
is supplied continuously. Therefore, it is unnecessary to take the
rotation period into consideration strictly.
[0004] On the other hand, when gas is supplied periodically, it is
necessary to take into consideration a relation between gas supply
port and rotation period. For example, according to a film forming
method called ALD (Atomic Layer Deposition), two kinds (or more
kinds) raw material gases used for forming films are alternately
supplied onto a substrate one kind by one kind under given film
forming condition (temperature, time or the like), the gases are
allowed to be adsorbed one atomic layer by one atomic layer, and a
film is formed utilizing surface reaction. According to this ALD
method, when two gases A and B alternately flow, the film forming
process proceeds by repeating the following cycle: supply of gas
A.fwdarw.purge (remove remaining gas).fwdarw.supply of gas
B.fwdarw.purge (remove remaining gas).
[0005] Assume that the time required for one cycle is defined as
gas supply period T (seconds) and a rotation period of a substrate
is defined as P (seconds). If the supplying cycle of gas and the
rotation of a substrate are in synchronization with each other,
i.e., if a numeric value of an integral multiple of T and a numeric
value of an integral multiple of P match with each other, and if
the matched numeric value is defined as L (seconds), gas is
supplied to the same point of the substrate at time L (see FIG. 1),
and a case in which the consistency cannot be enhanced occurs
contrary to the purpose of eliminating the influence of distance
from the gas supply port by means of rotation.
[0006] Hence, it is a main object of the present invention to
provide a substrate processing apparatus capable of preventing or
restraining the reaction gas supply period and the rotation period
of a substrate from being brought into synchronization with each
other, thereby preventing the consistency of thickness of a film
formed on the substrate over its entire surface from being
deteriorated. It is also an object of the invention to provide a
producing method of a semiconductor device.
[0007] According to one aspect of the present invention, there is
provided a substrate processing apparatus, comprising a processing
chamber for processing a substrate; a substrate rotating mechanism
for rotating the substrate; and a gas supply unit for supplying gas
to the substrate, at least two kinds of gases A and B being
alternately supplied a plurality of times to form a desired film on
the substrate, a controller for controlling a rotation period of
the substrate or a gas supply period defined as a time period
between an instant when the gas A is made to flow and an instant
when the gas A is made to flow next time such that the rotation
period and the gas supply period are not brought into
synchronization with each other at least while the alternate gas
supply is carried out predetermined times.
[0008] According to another aspect of the present invention, there
is provided a substrate processing apparatus, comprising a
processing chamber for processing a substrate; a substrate rotating
mechanism for rotating the substrate; a gas supply unit for
supplying gas to the substrate, at least two kinds of gases A and B
being alternately supplied a plurality of times to form a desired
film on the substrate, and a controller for controlling a rotation
period of the substrate or gas supply time such that the alternate
supplying operation of the gases A and B is carried out
predetermined times between the instant when the gas A is supplied
to an arbitrary location of the substrate and the instant when the
gas A is supplied to the arbitrary location of the substrate next
time.
[0009] According to still another aspect of the resent invention,
there is provided a substrate processing apparatus, comprising a
processing chamber for processing a substrate; a substrate rotating
mechanism for rotating the substrate; and a gas supply unit for
supplying gas to the substrate, at least two kinds of gases A and B
being alternately supplied a plurality of times to form a desired
film on the substrate, and a controller for controlling a rotation
period P of the substrate or a gas supply period T defined by a
time period between the instant when the gas A is made to flow and
the instant when the gas A is made to flow next time such that the
gas supply period T and the rotation period P satisfy the following
equation (1):
|mP-nT|>.noteq.0 (n and m are natural numbers) (1)
(wherein>.noteq.0 means that truly greater than 0, and
.parallel. represents an absolute value).
[0010] According to still another aspect of the resent invention,
there is provided a substrate processing apparatus, comprising a
processing chamber for processing a substrate; a substrate rotating
mechanism for rotating the substrate; a gas supply unit for
supplying gas to the substrate; and a controller for controlling
the rotating mechanism and the gas supply system such that a supply
cycle of the reaction gas and a rotation period of the substrate do
not come into synchronization with each other more than a given
time when the reaction gas is supplied to the reaction chamber
periodically.
[0011] According to still another aspect of the resent invention,
there is provided a producing method of a semiconductor device,
comprising with a substrate processing apparatus, comprising: a
processing chamber for processing a substrate; a substrate rotating
mechanism for rotating the substrate; and a gas supply unit for
supplying gas to the substrate, at least two kinds of gases A and B
being alternately supplied a plurality of times to form a desired
film on the substrate, wherein the substrate processing apparatus
further comprises a controller for controlling a rotation period of
the substrate or a gas supply period defined as a time period
between an instant when the gas A is made to flow and an instant
when the gas A is made to flow next time such that the rotation
period and the gas supply period are not brought into
synchronization with each other at least while the alternate gas
supply is carried out predetermined times, processing the
substrate.
[0012] According to still another aspect of the resent invention,
there is provided a producing method of a semiconductor device,
comprising with a substrate processing apparatus, comprising a
processing chamber for processing a substrate; a substrate rotating
mechanism for rotating the substrate; and a gas supply unit for
supplying gas to the substrate, at least two kinds of gases A and B
being alternately supplied a plurality of times to form a desired
film on the substrate, wherein the substrate processing apparatus
further comprises a controller for controlling a rotation period of
the substrate or gas supply time such that the alternate supplying
operation of the gases A and B is carried out predetermined times
between the instant when the gas A is supplied to an arbitrary
location of the substrate and the instant when the gas A is
supplied to the arbitrary location of the substrate next time,
processing the substrate.
[0013] According to still another aspect of the resent invention,
there is provided a producing method of a semiconductor device,
comprising with a substrate processing apparatus, comprising a
processing chamber for processing a substrate; a substrate rotating
mechanism for rotating the substrate; and a gas supply unit for
supplying gas to the substrate, at least two kinds of gases A and B
being alternately supplied a plurality of times to form a desired
film on the substrate, wherein the substrate processing apparatus
further comprises a controller for controlling a rotation period P
of the substrate or a gas supply period T defined by a time period
between the instant when the gas A is made to flow and the instant
when the gas A is made to flow next time such that the gas supply
period T and the rotation period P satisfy the following equation
(1):
|mP-nT|>.noteq.0 (n and m are natural numbers) (1)
(wherein>.noteq.0 means that truly greater than 0, and
.parallel. represents an absolute value), processing the
substrate.
BRIEF DESCRIPTION OF THE FIGURES IN THE DRAWINGS
[0014] FIG. 1 is a diagram used for explaining a gas supply state
when a rotation period of a substrate to be processed and a gas
supply period come into synchronization with each other.
[0015] FIG. 2 is a diagram used for explaining a gas supply state
when a rotation period of a substrate to be processed and a gas
supply period do not come into synchronization with each other.
[0016] FIG. 3A shows a film thickness distribution when the
substrate to be processed is not rotated.
[0017] FIG. 3B shows a film thickness distribution when the
substrate to be processed is rotated and the rotation period of the
substrate to be processed and gas supply period come into
synchronization with each other.
[0018] FIG. 3C shows a film thickness distribution when the
substrate to be processed is rotated and the rotation period of the
substrate to be processed and gas supply period does not come into
synchronization with each other.
[0019] FIG. 4 is a schematic longitudinal sectional view for
explaining a vertical substrate processing furnace of a substrate
processing apparatus according to one embodiment of the present
invention.
[0020] FIG. 5 is a schematic transversal sectional view for
explaining the vertical substrate processing furnace of the
substrate processing apparatus according to the one embodiment of
the present invention.
[0021] FIG. 6 is a schematic perspective view for explaining the
substrate processing apparatus body according to the one embodiment
of the present invention.
PREFERABLE MODE FOR CARRYING OUT THE INVENTION
[0022] In a preferred embodiment of the invention, the rotation
period P and the gas supply period T are finely adjusted to satisfy
the following equation (1):
|mP-nT|>.noteq.0 (n and m are natural numbers) (1)
(wherein>.noteq.0 means that greater than 0, and H represents an
absolute value).
[0023] If the equation (1) is satisfied, it is possible to prevent
the supply start timing of gas A during the gas supply period from
coming into synchronization with a rotation position of the
substrate (see FIG. 2), and the consistency can be improved.
[0024] If the time span during which the equation (1) is satisfied
is taken into consideration, it is of course sufficient if the
equation (1) is satisfied for the entire film forming time, but the
condition may be weakened a little, and it is conceived that there
is no problem in terms of consistency if the synchronization is not
established for a time span corresponding to 10 cycles (10T
(seconds) if the above symbol is used), for example, because the
gas injection timing is sufficiently dispersed.
Embodiment 1
[0025] The following description is based on an example in which
DCS(SiH.sub.2Cl.sub.2, dichlor-silane) and NH.sub.3 (ammonia) are
alternately supplied twice or more, and an SiN (silicon nitride)
film is formed on a silicon wafer by the ALD method.
[0026] When a rotation period P of a wafer is 6.6666 seconds and a
gas supply period T is 20 seconds, since 3.times.6.6666=20, time 20
seconds required for three rotations becomes equal to the gas
supply period T. Therefore, if the wafer is rotated three times,
the rotation period of the wafer and the relative position of a gas
supply nozzle become the same, the gas is adversely supplied to the
same location again, and a thickness of the film at its portion
located upstream of the gas flow is increased. FIG. 3B shows a film
thickness distribution at that time. A left portion of the film is
thick, and a portion of the film from its right side toward the
right lower portion becomes thin. It can be found that when a wafer
is rotated, the distribution becomes concentric and the consistency
is enhanced, but if the rotation period of the wafer and the gas
supply period come into synchronization with each other, such
effect cannot be obtained. If the wafer is not rotated, the
thickness consistency over the entire surface of the wafer is 12%
(see FIG. 3A), and the thickness consistency over the entire
surface of the wafer when the synchronization is established is
about 7% (see FIG. 3B).
[0027] The thicknesses in FIGS. 3A and 3B are different from each
other. This is because that since the wafer in FIG. 3B is rotated,
when the thick portion becomes close to a nozzle of DCS, DCS is
supplied.
[0028] On the other hand, when the rotation period P of the wafer
is 6.6666 seconds and the gas supply period T is 21 seconds, the
DCS injecting timing does not come into synchronization with the
first injection until 1,260 seconds are elapsed. As many as 60
cycles have been carried out so far, the injection of the DCS is
sufficiently dispersed, and concentric film thickness distribution
having no deviation is obtained as shown in FIG. 3C. When the
rotation period of a wafer and the gas supply period are not in
synchronization with each other until so many cycles are carried
out, the consistency of film thickness of the wafer over the entire
surface thereof is improved to 3.7% (see FIG. 3C).
[0029] FIG. 4 schematically shows showing a structure of a vertical
type substrate processing furnace according to this embodiment, and
is a vertical sectional view of a processing furnace portion. FIG.
5 schematically shows showing a structure of the vertical type
substrate processing furnace according to this embodiment, and is a
transverse sectional view of the processing furnace portion. A
reaction tube 203 as a reaction container for processing wafers 200
which are substrates is provided in a heater 207 which is heating
means. A lower end opening of the reaction tube 203 is air-tightly
closed with a seal cap 219 which is a lid through an O-ring 220
which is a hermetic member. At least the heater 207, the reaction
tube 203 and the seal cap 219 form a processing furnace 202. The
reaction tube 203 and the seal cap 219 form a reaction chamber 201.
A boat 217, which is a substrate holding means, stands from the
seal cap 219 through a quartz cap 218. The quartz cap 218 is a
holding member which holds the boat. The boat 217 is inserted into
the processing furnace 202. A plurality of wafers 200 to be
batch-processed are multi-stacked in an axial direction of the tube
in their horizontal attitude. The heater 207 heats the wafers 200
inserted into the processing furnace 202 to a predetermined
temperature.
[0030] The processing furnace 202 is provided with two gas supply
tube 232a and 232b as supply tubes for supplying a plurality of
kinds (here, two kinds) of gases. From the first gas supply tube
232a, reaction gas is supplied into the processing furnace 202
through a first mass flow controller 241a which is flow rate
control means, a first valve 243a which is an open/close valve and
a buffer chamber 237 formed in the later-described processing
furnace 202. From the second gas supply tube 232b, reaction gas is
supplied to the processing furnace 202 through a second mass flow
controller 241b which is flow rate control means, a second valve
243b which is an open/close valve, a gas reservoir 247, a third
valve 243c which is an open/close valve, and a later-described gas
supply unit 249.
[0031] The processing furnace 202 is connected to a vacuum pump 246
which is an exhaust means through a fourth valve 243d by means of a
gas exhaust tube 231 which is an exhaust tube for exhausting gas,
and the processing furnace 202 is evacuated. The fourth valve 243d
is an open/close valve. By opening or closing the fourth valve
243d, the processing furnace 202 can be evacuated or the evacuation
can be stopped. The opening degree of the fourth valve 243d can be
adjusted using pressure.
[0032] A buffer chamber 237 is provided in an arc space between the
wafers 200 and an inner wall of the reaction tube 203 constituting
the processing furnace 202. The buffer chamber 237 is a gas
dispersing space extending in a stacking direction of the wafers
200. The buffer chamber 237 extends along the inner wall from a
lower portion to an upper portion of the reaction tube 203. An end
of a wall of the buffer chamber 237 adjacent to the wafers 200 is
provided with first gas supply holes 248a for supplying gas. The
first gas supply holes 248a are opened toward a center of the
reaction tube 203. The first gas supply holes 248a have the same
opening areas from the lower portion to the upper portion, and the
holes are provided at the same pitch.
[0033] A nozzle 233 is disposed at an end of the buffer chamber 237
opposite from the end at which the first gas supply holes 248a are
provided.
[0034] The nozzle 233 is disposed along the stacking direction of
the wafers 200 from the lower portion to the upper portion of the
reaction tube 203. The nozzle 233 is provided with second gas
supply holes 248b for supplying a plurality of gases. When a
pressure difference between the buffer chamber 237 and the
processing furnace 202 is small, the opening areas of the second
gas supply holes 248b may be the same and the opening pitches may
be the same from its upstream side toward its downstream side, but
if the pressure difference is great, the opening areas may be
increased or the opening pitches may be reduced from the upstream
side toward the downstream side.
[0035] In this invention, if the opening areas or the opening
pitches of the second gas supply holes 248b are adjusted from the
upstream side to the downstream side, gases can be injected
substantially at the same flow rate although flowing speeds of
gases are different from one another among the gas supply holes
248b. Gas injected from each second gas supply hole 248b is
injected to the buffer chamber 237 and is once introduced, and the
flowing speeds of gases are equalized.
[0036] That is, in the buffer chamber 237, gas particle velocity of
gas injected from each second gas supply hole 248b is moderated,
and then the gas is injected into the processing furnace 202 from
the first gas supply holes 248a. During this time, gases injected
from each of the second gas supply holes 248b had equal flow rates
and flowing speeds when the gases were injected from the first gas
supply holes 248a.
[0037] A first rod-like electrode 269 which is a first electrode
having a thin and long structure, and a second rod-like electrode
270 which is a second electrode, are disposed in the buffer chamber
237 such as to extend from an upper portion to a lower portion in
the buffer chamber 237. The first rod-like electrode 269 and the
second rod-like electrode 270 are protected by electrode protection
tubes 275 which are protection tubes for protecting the electrodes.
One of the first rod-like electrode 269 and the second rod-like
electrode 270 is connected to a high frequency power supply 273
through a matching device 272, and the other one is grounded
(reference potential). As a result, plasma is produced in a plasma
producing region 224 between the first rod-like electrode 269 and
the second rod-like electrode 270.
[0038] The electrode protection tubes 275 can be inserted in the
buffer chamber 237 in a state where the first rod-like electrode
269 and the second rod-like electrode 270 are isolated from
atmosphere in the buffer chamber 237. If the atmosphere in the
electrode protection tube 275 is the same as outside air
(atmosphere), the first rod-like electrode 269 and the second
rod-like electrode 270 respectively inserted into the electrode
protection tubes 275 are oxidized by heat from the heater 207.
Thus, there is provided an inert gas purge mechanism which charges
or purges inert gas such as nitrogen into and from the electrode
protection tube 275, reduces the oxygen concentration to a
sufficiently low value, and prevents the first rod-like electrode
269 or the second rod-like electrode 270 from being oxidized.
[0039] A gas supply unit 249 is provided on an inner wall of the
reaction tube 203 at a location away from the first gas supply
holes 248a through 120.degree.. When a plurality of kinds of gases
are supplied to the wafers 200 alternately one kind by one kind by
the ALD method to form films, the gas supply unit 249 and the
buffer chamber 237 alternately supply the gases to the wafers
200.
[0040] Like the buffer chamber 237, the gas supply unit 249 also
includes third gas supply holes 248c for supplying gas at the same
pitch to a position adjacent to the wafer. The second gas supply
tube 232b is connected to the gas supply unit 249.
[0041] When the pressure difference between the buffer chamber 237
and the processing furnace 202 is small, it is preferable that the
opening areas of the third gas supply holes 248c are equal to each
other from the upstream side to the downstream side and the holes
are arranged at the same opening pitch, but when the pressure
difference is great, it is preferable that the opening areas are
increased or the opening pitch is reduced from the upstream side to
the downstream side.
[0042] The boat 217 is provided at the central portion in the
reaction tube 203. The plurality of wafers 200 are placed on the
boat 217 at the multi-stacked manner at equal distances from one
another. The boat 217 is brought into and out from the reaction
tube 203 by a boat elevator mechanism (not shown). To enhance the
consistency of processing, a boat rotating mechanism 267, which is
a rotating means for rotating the boat 217, is provided. If the
boat rotating mechanism 267 is rotated, the boat 217 held by the
quartz cap 218 is rotated.
[0043] A controller 121 is a control means. The controller 121 is
connected to the first and second mass flow controllers 241a and
241b, first to fourth valves 243a, 243b, 243c and 243d, the heater
207, the vacuum pump 246, the boat rotating mechanism 267, a boat
vertically moving mechanism (not shown), the high frequency power
supply 273 and the matching device 272. The controller 121 adjusts
the flow rates of the first and second mass flow controllers 241a
and 241b, opens and closes first to third valves 243a, 243b and
243c, opens and closes the fourth valve 243d and adjusts the
pressure of the fourth valve 243d, adjusts the temperature of the
heater 207, starts and stops the vacuum pump 246, adjusts the
rotation speed of the boat rotating mechanism 267, controls the
vertical motion of the boat vertically moving mechanism, controls
the electricity supply to the high frequency power supply 273, and
controls impedance by the matching device 272.
[0044] Next, an example of forming a nitride film (SiN film) using
DCS (SiH.sub.2Cl.sub.2, dichlor-silane) and NH.sub.3 gas by the ALD
method will be explained.
[0045] First, wafers 200 on which films are to be formed are placed
on the boat 217, and the boat 217 is brought into the processing
furnace 202. Then, the following three steps are carried out.
[0046] Although DCS is first allowed to flow into the furnace in
the following example, a method in which NH.sub.3 is allowed to
flow first is also substantially the same.
[0047] (1) A desired amount of DCS is previously stored in a state
where 243b is opened and 243c is closed (it is preferable that raw
material is stored in the gas reservoir 247 previously at the first
cycle, and after the second cycle, the raw material is stored in
the gas reservoir 247 at any time except at event in which the raw
material from the gas reservoir 247 is discharged so as not to
waste the time).
[0048] (2) Before DCS stored in the gas reservoir 247 is
discharged, it is preferable to previously flow inert gas such as
N.sub.2 from the buffer chamber 237. This avoids an adverse case in
which DCS stored in the gas reservoir 247 flows into the reaction
tube 203 in a rush due to the pressure difference between the gas
reservoir 247 and the reaction tube 203 in the next event, and the
DCS back flows into the buffer chamber 237 from the gas supply port
248a of the buffer chamber 237.
[0049] (3) By opening the valve 243c located downstream from the
gas reservoir 247, DCS stored in the gas reservoir 247 is supplied
to the wafers 200 which are substrates to be processed, from the
gas supply ports 248c formed in the buffer chamber (gas supply
unit) 249, each provided between the substrates through the buffer
chamber (gas supply unit) 249. The pressure of the adjusting means
(valve 243d such as a butterfly valve provided in an intermediate
portion of an exhaust tube) of pressure in the furnace is set high
so that the partial pressure of DCS becomes high so as to
facilitate the adsorption of raw material. In this case also, it is
preferable to keep flowing inert gas such as N.sub.2 from the
buffer chamber 237. The wafer temperature at that time is 300 to
600.degree. C.
[0050] (4) The valve 243c is closed and the supply of DCS to the
gas reservoir 247 is stopped. After the valve 243c is closed, the
time elapsed until the next supply starts can be used for storing
DCS (that is, since DCS gas can be stored in the gas reservoir 247
while another event is being carried out, it is unnecessary to
prepare extra time for an event of only storing).
[0051] (5) Next, DCS is removed from the reaction tube 203 and the
buffer chamber (gas supply unit) 249 by the vacuum exhaust means
243. At that time, it is effective for replacing gas by adding an
inert gas line between the valve 243c and the buffer chamber (gas
supply unit) 249, and combining a push-out operation by means of
inert gas and an evacuation operation.
[0052] (6) Next, NH.sub.3 is supplied into the buffer chamber 237
from the gas supply tube 232a through the nozzle 233 connected to
the buffer chamber 237. At that time also, it is preferable to flow
inert gas from the buffer chamber (gas supply unit) 249 for the
same reason as that described above.
[0053] (7) The NH.sub.3 is supplied to the buffer chamber 237 from
the nozzle 233 such that the pressure in the buffer chamber 237
becomes uniform. The NH.sub.3 is supplied to the wafers 200 as the
substrates to be processed from the gas supply holes 248b formed in
the buffer chamber 237 such that each gas supply hole is located
between the adjacent substrates. If this embodiment is used, it is
possible to supply NH.sub.3 to the plurality of wafers 200 as the
substrates to be processed in the same manner.
[0054] The temperature of the heater 207 at that time is set such
that the wafers 200 are heated to 300 to 600.degree. C. Since the
NH.sub.3 has high reaction temperature, the NH.sub.3 does not react
at the wafer temperature. Therefore, the NH.sub.3 is plasma-excited
and allowed to flow as active species. Therefore, the reaction can
be carried out in the set low wafer temperature range.
[0055] (8) The supply of NH.sub.3 into the reaction tube 203 is
stopped.
[0056] (9) Next, the removing operation of the NH.sub.3 from the
reaction tube 203 and the buffer chamber 237 is carried out by an
exhausting operation carried out using the vacuum exhausting means
243. In this case also, it is effective to combine a push-out
operation by means of inert gas and an evacuation operation.
[0057] The operations (1) to (9) correspond to one cycle, and by
repeating the operations (1) to (9), the film forming process
proceeds.
[0058] In an ALD apparatus, gas is adsorbed on a backing film
surface. An adsorption amount of gas is proportional to the
pressure of gas and exposed time of gas. Therefore, in order to
allow a desired given amount of gas to be adsorbed in a short time,
it is necessary to increase the gas pressure in a short time. In
this aspect, in the embodiment, the valve 243d is closed and DCS
stored in the gas reservoir 247 is supplied instantaneously.
Therefore, the pressure of DCS in the reaction tube 203 can be
increased abruptly, and a desired given amount of gas can be
adsorbed instantaneously.
[0059] In this embodiment, while DCS is stored in the gas reservoir
247, NH.sub.3 is plasma-excited and is supplied as the active
species and gas is exhausted from the processing furnace 202. These
operations are necessary steps in the ALD method. Therefore, a
special step for storing DCS is not required. Gas is exhausted from
the processing furnace 202, NH.sub.3 gas is removed and then DCS is
allowed to flow. Therefore, NH.sub.3 gas and DCS do not react with
each other on the way to the wafers 200. The supplied DCS can
effectively react only with NH.sub.3 which are adsorbed on the
wafer 200.
[0060] Next, referring to FIG. 6, an outline of the semiconductor
producing apparatus, which is one example of the semiconductor
producing apparatus to which the present invention is applied, will
be explained.
[0061] A cassette stage 105, which functions as a holding tool
delivery member which delivers a cassette 100 (a substrate
accommodating container) between a casing 101 and an external
transfer apparatus (not shown), is provided on a front surface side
in the casing 101. A cassette elevator 115 which functions as an
elevator means is provided on a rear side of the cassette stage
105. A cassette loader 114 which functions as a transfer means is
mounted on the cassette elevator 115. A cassette shelf 109 which
functions as a placing means of the cassette 100 is provided on the
rear side of the cassette elevator 115, and an auxiliary cassette
shelf 110 is provided also above the cassette stage 105. A clean
unit 118 is provided above the auxiliary cassette shelf 110 so that
clean air can flow into the casing 101.
[0062] The processing furnace 202 is provided above a rear portion
of the casing 101. A boat elevator 121 which functions as an
elevator means is provided below the processing furnace 202. The
boat elevator 121 vertically moves the boat 217, which functions as
the substrate holding means, to and from the processing furnace
202. The boat 217 holds the wafers 200 as substrates in the
multi-stacked manner in their horizontal attitudes. The seal cap
219 is mounted as a lid on a tip end of a vertically moving member
122 which is mounted on the boat elevator 121, and the seal cap 219
vertically supports the boat 217. A loading elevator 113 is
provided as an elevator means between the boat elevator 121 and the
cassette shelf 109. A wafer loader 112 which functions as a
transfer means is mounted on the loading elevator 113. A furnace
opening shutter 116 which functions as a shielding member is
provided by the side of the boat elevator 121. The furnace opening
shutter 116 has an opening/closing mechanism and closes a lower
surface of the processing furnace 202.
[0063] In the cassette 100, the wafers 200 are rotated through
90.degree. by the cassette stage 105 such that wafers 200 are
brought into the cassette stage 105 from an external transfer
apparatus (not shown) and the wafers 200 assume the horizontal
attitudes. The cassette 100 is transferred to the cassette shelf
109 or the auxiliary cassette shelf 110 from the cassette stage 105
by cooperation of vertical movement and lateral movement of the
cassette elevator 115 and forward and backward movement and
rotational movement of the cassette loader 114.
[0064] The cassette shelf 109 includes a transfer shelf 123 in
which cassette 100 to be transferred by the wafer loader 112 is
accommodated. The cassette 100 on which the wafers 200 are set is
transferred to the transfer shelf 123 by the cassette elevator 115
and the cassette loader 114.
[0065] If the cassette 100 is transferred to the transfer shelf
123, the wafers 200 are loaded on the boat 217, which is lowered
from the transfer shelf 123 by cooperation of forward and backward
motion and rotational motion of the wafer loader 112 and vertical
motion of the loading elevator 113.
[0066] If a necessary number of wafers 200 are loaded on the boat
217, the boat 217 is inserted into the processing furnace 202 by
the boat elevator 121, and the processing furnace 202 is
air-tightly closed with the seal cap 219. In the air-tightly closed
processing furnace 202, the wafers 200 are heated, processing gas
is supplied into the processing furnace 202, and the wafers 200 are
processed.
[0067] If the processing of the wafers 200 is completed, the wafers
200 are moved to the cassette 100 of the transfer shelf 123 from
the boat 217 following the above procedure in reverse, the cassette
100 is moved to the cassette stage 105 from the transfer shelf 123
by the cassette loader 114, and is transferred out from the casing
101 by the external transfer apparatus (not shown). In the state in
which the boat 217 is lowered, the furnace opening shutter 116
closes the lower surface of the processing furnace 202 to prevent
outside air from entering into the processing furnace 202.
[0068] The transfer motions of the cassette loader 114 and the like
are controlled by transfer control means 124.
[0069] The entire disclosure of Japanese Patent Application No.
2004-70136 filed on Mar. 12, 2004 including specification, claims,
drawings and abstract are incorporated herein by reference in its
entirety.
[0070] Although various exemplary embodiments have been shown and
described, the invention is not limited to the embodiments shown.
Therefore, the scope of the invention is intended to be limited
solely by the scope of the claims that follow.
INDUSTRIAL APPLICABILITY
[0071] As explained above, according to the preferred embodiment of
the present invention, there is proposed a substrate processing
apparatus and a producing method of a semiconductor device both
capable of preventing or restraining the reaction gas supply period
and the rotation period of a substrate from being brought into
synchronization with each other, thereby preventing the consistency
of thickness of a film formed on the substrate over its entire
surface from being deteriorated.
[0072] As a result, the present invention can especially preferably
be utilized for a substrate processing apparatus and a producing
method of a semiconductor device which process a semiconductor
substrate, such as a semiconductor Si wafer, using gas.
* * * * *