U.S. patent application number 12/047691 was filed with the patent office on 2008-09-18 for substrate processing apparatus, substrate processing method and storage medium.
This patent application is currently assigned to TOKYO ELECTRON LIMITED. Invention is credited to Tadashi Onishi.
Application Number | 20080223825 12/047691 |
Document ID | / |
Family ID | 39472598 |
Filed Date | 2008-09-18 |
United States Patent
Application |
20080223825 |
Kind Code |
A1 |
Onishi; Tadashi |
September 18, 2008 |
SUBSTRATE PROCESSING APPARATUS, SUBSTRATE PROCESSING METHOD AND
STORAGE MEDIUM
Abstract
A substrate processing apparatus includes: a gas supply
mechanism supplying gas containing a halogen element and basic gas
into a process chamber; and a first temperature adjusting member
and a second temperature adjusting member adjusting a temperature
of the substrate in the process chamber, wherein the second
temperature adjusting member adjusts the temperature of the
substrate to a higher temperature than the first temperature
adjusting member.
Inventors: |
Onishi; Tadashi;
(Nirasaki-shi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
TOKYO ELECTRON LIMITED
Tokyo
JP
|
Family ID: |
39472598 |
Appl. No.: |
12/047691 |
Filed: |
March 13, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60941842 |
Jun 4, 2007 |
|
|
|
Current U.S.
Class: |
216/58 ;
156/345.37 |
Current CPC
Class: |
H01L 21/68721 20130101;
H01L 21/67248 20130101; H01L 21/02057 20130101; H01L 21/68742
20130101; H01L 21/67126 20130101; H01L 21/67109 20130101 |
Class at
Publication: |
216/58 ;
156/345.37 |
International
Class: |
C23F 1/00 20060101
C23F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 16, 2007 |
JP |
2007-068179 |
Claims
1. A substrate processing apparatus removing an oxide film on a
surface of a substrate by chemical processing and heat treatment,
the apparatus comprising: a gas supply mechanism supplying gas
containing a halogen element and basic gas into a process chamber;
and a first temperature adjusting member and a second temperature
adjusting member adjusting a temperature of the substrate in the
process chamber, wherein said second temperature adjusting member
adjusts the temperature of the substrate to a higher temperature
than said first temperature adjusting member.
2. The substrate processing apparatus according to claim 1, wherein
the inside of the process chamber is airtightly closable.
3. The substrate processing apparatus according to claim 1, further
comprising an exhaust mechanism exhausting the inside of the
process chamber.
4. The substrate processing apparatus according to claim 1, further
comprising a support member supporting the substrate in the process
chamber, wherein said second temperature adjusting member is
thermally in contact with said support member, and said first
temperature adjusting member is capable of thermally coming into
contact with and separating from said support member.
5. The substrate processing apparatus according to claim 4, wherein
a rear surface of said support member is exposed to an external
part of the process chamber, and said first temperature adjusting
member is capable of thermally coming into contact with or
separating from the rear surface of said support member, in the
external part of the process chamber.
6. The substrate processing apparatus according to claim 4, wherein
a rear surface of said support member is covered by said second
temperature adjusting member, and said first temperature adjusting
member comes into contact with said second temperature adjusting
member.
7. The substrate processing apparatus according to claim 4, wherein
said second temperature adjusting member is buried in said support
member, and said first temperature adjusting member comes into
contact with said support member.
8. The substrate processing apparatus according to claim 4, wherein
total heat capacity of said support member and said second
temperature adjusting member is smaller than heat capacity of said
first temperature adjusting member.
9. The substrate processing apparatus according to claim 1, wherein
said first temperature adjusting member is a mounting table on
which the substrate is placed in the process chamber, and the
apparatus further comprising a lifter mechanism lifting up the
substrate from the mounting table in the process chamber, wherein
the temperature of the substrate which has been lifted up from said
mounting table by said lifter mechanism is adjusted by said second
temperature adjusting member.
10. The substrate processing apparatus according to claim 9,
further comprising a partition member disposed around the substrate
which has been lifted up from said mounting table by said lifter
mechanism; a first exhaust mechanism exhausting the inside of the
process chamber above said partition member; and a second exhaust
mechanism exhausting the inside of the process chamber under said
partition member.
11. The substrate processing apparatus according to claim 9,
wherein said gas supply mechanism supplies the gas containing the
halogen element and the basic gas to the inside of the process
chamber above the substrate which has been lifted up from said
mounting table by said lifter mechanism.
12. A substrate processing method of removing an oxide film on a
surface of a substrate by chemical processing and heat treatment,
the method comprising the steps of: supplying gas containing a
halogen element and basic gas to the inside of a process chamber
and adjusting a temperature of the substrate by a first temperature
adjusting member, thereby turning the oxide film on the surface of
the substrate into a reaction product; and adjusting the
temperature of the substrate to a higher temperature by the second
temperature adjusting member than the first temperature adjusting
member, thereby vaporizing the reaction product.
13. The substrate processing method according to claim 12, wherein
the inside of the process chamber is exhausted.
14. The substrate processing method according to claim 12, wherein
the substrate is supported by a support member including the second
temperature adjusting member, and wherein, in said step of turning
the oxide film on the surface of the substrate into the reaction
product, the first temperature adjusting member is brought into
thermal contact with the support member, and wherein, in said step
of vaporizing the reaction product, the first temperature adjusting
member is thermally separated from the support member.
15. The substrate processing method according to claim 14, wherein
the first temperature adjusting member is thermally brought into
contact with or separated from the support member, in an external
part of the process chamber.
16. The substrate processing method according to claim 14, wherein
total heat capacity of the support member and the second
temperature adjusting member is smaller than heat capacity of the
first temperature adjusting member.
17. The substrate processing method according to claim 12, wherein,
in said step of turning the oxide film on the surface of the
substrate into the reaction product, the temperature of the
substrate is adjusted while the substrate is placed on a mounting
table as the first temperature adjusting member, and wherein, in
said step of vaporizing the reaction product, the temperature of
the substrate is adjusted by the second temperature adjusting
member while the substrate is lifted up from the mounting table in
the process chamber.
18. A storage medium containing a recorded program executable by a
control unit of a substrate processing apparatus, the program
causing the substrate processing apparatus to perform the substrate
processing method according to claim 12 when executed by the
control unit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a substrate processing
apparatus and a substrate processing method for removing an oxide
film on a surface of a substrate by chemical processing and heat
treatment.
[0003] 2. Description of the Related Art
[0004] In manufacturing processes of semiconductor devices, for
instance, various processing steps are performed while the inside
of a process chamber housing a semiconductor wafer (hereinafter,
referred to as a "wafer") is set in a low-pressure state close to a
vacuum state. As an example of the processing utilizing such a
low-pressure state, there has been known COR (Chemical Oxide
Removal) processing for chemically removing an oxide film (silicon
dioxide (SiO.sub.2)) existing on a surface of a silicon wafer (see,
the specification of US Patent Application Publication No.
2004/0182417 and the specification of US Patent Application
Publication No. 2004/0184792). In this COR processing, under the
low-pressure state, mixed gas of gas containing a halogen element
and basic gas is supplied while the temperature of the wafer is
adjusted to a predetermined value, thereby turning the oxide film
into a reaction product mainly containing ammonium fluorosilicate,
and then the reaction product is vaporized (sublimated) by heating
to be removed from the wafer. In this case, hydrogen fluoride gas
(HF) is used as the gas containing the halogen element, for
instance, and ammonia gas (NH.sub.3) is used as the basic gas, for
instance.
SUMMARY OF THE INVENTION
[0005] As an apparatus for such COR processing, there has been
generally known an apparatus including: a chemical processing
chamber in which the step of turning an oxide film on a surface of
a wafer into a reaction product is performed under a relatively low
temperature; and a heat treatment chamber in which the step of
removing the reaction product from the wafer by heating and
sublimating the reaction product is performed under a relatively
high temperature. However, such a processing apparatus in which the
chemical processing chamber and the heat treatment chamber are
separately provided has a disadvantage that the apparatus becomes
large, leading to an increase in footprint since the number of
process chambers increases. Further, separately providing the
chemical processing chamber and the heat treatment chamber
necessitates the transfer of a wafer therebetween, which requires a
complicated carrier mechanism and further may cause a problem that
during the transfer, the wafer is contaminated and contaminants are
released from the wafer.
[0006] The present invention was made in view of the above and its
object is to provide a substrate processing apparatus and a
substrate processing method capable of performing chemical
processing and heat treatment in the same process chamber.
[0007] To solve the above problems, according to the present
invention, there is provided a substrate processing apparatus
removing an oxide film on a surface of a substrate by chemical
processing and heat treatment, the apparatus including: a gas
supply mechanism supplying gas containing a halogen element and
basic gas into a process chamber; and a first temperature adjusting
member and a second temperature adjusting member adjusting a
temperature of the substrate in the process chamber, wherein the
second temperature adjusting member adjusts the temperature of the
substrate to a higher temperature than the first temperature
adjusting member.
[0008] In this substrate processing apparatus, the inside of the
process chamber may be airtightly closable. The substrate
processing apparatus may further include an exhaust mechanism
exhausting the inside of the process chamber.
[0009] For example, the substrate processing apparatus further
includes a support member supporting the substrate in the process
chamber, wherein the second temperature adjusting member is
thermally in contact with the support member, and the first
temperature adjusting member is capable of thermally coming into
contact with and separating from the support member. In this case,
a rear surface of the support member may be exposed to an external
part of the process chamber, and the first temperature adjusting
member may be capable of thermally coming into contact with or
separating from the rear surface of the support member, in the
external part of the process chamber. Further, a rear surface of
the support member may be covered by the second temperature
adjusting member, and the first temperature adjusting member may
come into contact with the second temperature adjusting member.
Further, the second temperature adjusting member may be buried in
the support member, and the first temperature adjusting member may
come into contact with the support member. Further, for example,
total heat capacity of the support member and the second
temperature adjusting member is smaller than heat capacity of the
first temperature adjusting member.
[0010] For example, in the substrate processing apparatus, the
first temperature adjusting member is a mounting table on which the
substrate is placed in the process chamber, and the apparatus
further includes a lifter mechanism lifting up the substrate from
the mounting table in the process chamber, wherein the temperature
of the substrate which has been lifted up from the mounting table
by the lifter mechanism is adjusted by the second temperature
adjusting member. In this case, the substrate processing apparatus
may further include: a partition member disposed around the
substrate which has been lifted up from the mounting table by the
lifter mechanism; a first exhaust mechanism exhausting the inside
of the process chamber above the partition member; and a second
exhaust mechanism exhausting the inside of the process chamber
under the partition member. Further, the gas supply mechanism may
supply the gas containing the halogen element and the basic gas to
the inside of the process chamber above the substrate which has
been lifted up from the mounting table by the lifter mechanism.
[0011] Further, according to the present invention, there is
provided a substrate processing method of removing an oxide film on
a surface of a substrate by chemical processing and heat treatment,
the method including the steps of: supplying gas containing a
halogen element and basic gas to the inside of a process chamber
and adjusting a temperature of the substrate by a first temperature
adjusting member, thereby turning the oxide film on the surface of
the substrate into a reaction product; and adjusting the
temperature of the substrate to a higher temperature by the second
temperature adjusting member than the first temperature adjusting
member, thereby vaporizing the reaction product. The inside of the
process chamber may be exhausted.
[0012] In the substrate processing method, for example, the
substrate may be supported by a support member including the second
temperature adjusting member, and in the step of turning the oxide
film on the surface of the substrate into the reaction product, the
first temperature adjusting member may be brought into thermal
contact with the support member, and in the step of vaporizing the
reaction product, the first temperature adjusting member may be
thermally separated from the support member. In this case, the
first temperature adjusting member may be thermally brought into
contact with or separated from the support member, in an external
part of the process chamber. Further, for example, total heat
capacity of the support member and the second temperature adjusting
member is smaller than heat capacity of the first temperature
adjusting member.
[0013] Further, in the substrate processing method, for example, in
the step of turning the oxide film on the surface of the substrate
into the reaction product, the temperature of the substrate is
adjusted while the substrate is placed on a mounting table as the
first temperature adjusting member, and in the step of vaporizing
the reaction product, the temperature of the substrate may be
adjusted by the second temperature adjusting member while the
substrate is lifted up from the mounting table in the process
chamber.
[0014] Further, according to the present invention, there is
provided a storage medium containing a recorded program executable
by a control unit of a substrate processing apparatus, the program
causing the substrate processing apparatus to perform the above
substrate processing method when executed by the control unit.
[0015] According to the present invention, since it is possible to
remove the oxide film on the surface of the substrate by the
chemical processing and the heat treatment in the same process
chamber, the substrate processing apparatus can be compact and a
complicated transfer sequence for substrate transfer is not
required. Further, the processing time can be shortened, which can
improve a throughput. Further, since the temperature of the
substrate is adjusted by the first temperature adjusting member and
the second temperature adjusting member, it is possible to rapidly
heat and cool the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a plane view showing a rough configuration of a
processing system;
[0017] FIG. 2 is an explanatory view of a COR apparatus according
to a first embodiment of the present invention, showing a state
where a cooling block is raised;
[0018] FIG. 3 is an explanatory view of the COR apparatus according
to the first embodiment of the present invention, showing a state
where the cooling block is lowered;
[0019] FIG. 4 is an explanatory view of a lifter mechanism;
[0020] FIG. 5 is an enlarged partial sectional view showing the
structure for attaching a peripheral edge portion of a face plate
to an upper surface of a base portion;
[0021] FIG. 6 is an enlarged partial sectional view showing the
structure for attaching the peripheral edge portion of the face
plate, which is different from the structure in FIG. 5;
[0022] FIG. 7 is a vertical sectional view used to explain the
cooling block;
[0023] FIG. 8 is a rough vertical sectional view showing the
structure of a surface of a wafer before a Si layer is etched;
[0024] FIG. 9 is a rough vertical sectional view showing the
structure of the surface of the wafer after the Si layer is
etched;
[0025] FIG. 10 is a rough vertical sectional view showing a state
of the surface of the wafer after the wafer undergoes COR
processing;
[0026] FIG. 11 is a rough vertical sectional view showing a state
of the surface of the wafer after the wafer undergoes film forming
processing for forming a SiGe layer;
[0027] FIG. 12 is an explanatory view of a COR apparatus according
to a second embodiment of the present invention, showing a state
where a wafer is placed on a mounting table (first processing
position);
[0028] FIG. 13 is an explanatory view of the COR apparatus
according to the second embodiment of the present invention,
showing a state where the wafer is lifted up from the mounting
table (second processing position); and
[0029] FIG. 14 is an explanatory view of a face plate with whose
lower surface a cooling block comes into direct contact.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Hereinafter, embodiments of the present invention will be
described, taking a case in which an oxide film (silicon dioxide
(SiO.sub.2)) formed on a surface of a silicon wafer (hereinafter,
referred to as a "wafer") is removed by COR processing, as an
example of a method and an apparatus for removing an oxide film on
a surface of a substrate by chemical processing and heat treatment.
In the specification and drawings, constituent elements having
substantially the same functions and structures are denoted by the
same reference numerals and symbols, and redundant description
thereof will be omitted.
(Overall Description of Processing System 1)
[0031] FIG. 1 is a plane view showing a rough configuration of a
processing system 1 including COR apparatuses 22. The COR apparatus
22 is a COR apparatus 22a according to a first embodiment of the
present invention or a COR apparatus 22b according to a second
embodiment of the present invention which will be described later.
The processing system 1 is configured to apply COR (Chemical Oxide
Removal) processing and film forming processing to a wafer W. In
the COR processing, a chemical processing step to turn a natural
oxide film (silicon dioxide (SiO.sub.2)) on a surface of the wafer
W into a reaction product and a heat treatment step to heat and
sublimate the reaction product are performed. In the chemical
processing step, gas containing a halogen element and basic gas are
supplied as process gases to the wafer W, thereby causing a
chemical reaction of the natural oxide film on the surface of the
wafer W and gas molecules of the process gases, so that the
reaction product is produced. The gas containing the halogen
element is, for example, hydrogen fluoride gas and the basic gas
is, for example, ammonia gas. In this case, the reaction product
mainly containing ammonia fluorosilicate is produced. The heat
treatment step is a PHT (Post Heat Treatment) step to heat the
wafer W having undergone the chemical processing to vaporize the
reaction product, thereby removing the reaction product from the
wafer. In the film forming processing, a film of SiGe or the like,
for instance, is epitaxially grown on the surface of the wafer W
from which the natural oxide film has been removed.
[0032] The processing system 1 shown in FIG. 1 includes: a
load/unload unit 2 loading/unloading the wafer W to/from the
processing system 1; a processing unit 3 applying the COR
processing and the film forming processing to the wafer W; and a
control unit 4 controlling the load/unload unit 2 and the
processing unit 3.
[0033] The load/unload unit 2 has a carrier chamber 12 in which a
first wafer carrier mechanism 11 carrying the wafer W in a
substantially disk shape is provided. The wafer carrier mechanism
11 has two carrier arms 11a, 11b each holding the wafer W in a
substantially horizontal state. On a side of the carrier chamber
12, there are, for example, three mounting tables 13 on which
carriers C each capable of housing the plural wafers W are mounted,
In each of the carriers C, the maximum of, for example, 25 pieces
of the wafers W can be horizontally housed in multi tiers at equal
pitches, and the inside of the carriers C is filled with an N.sub.2
gas atmosphere, for instance. Between the carriers C and the
carrier chamber 12, gate valves 14 are disposed, and the wafer W is
transferred between the carriers C and the carrier chamber 12 via
the gate valves 14. On sides of the mounting tables 13, provided
are: an orienter 15 which rotates the wafer W and optically
calculates its eccentricity amount to align the wafer W; and a
particle monitor 16 measuring an amount of particles of extraneous
matters and the like adhering on the wafer W. In the carrier
chamber 12, a rail 17 is provided, and the wafer carrier mechanism
11 is capable of approaching the carriers C, the orienter 15, and
the particle monitor 16 by moving along the rail 17.
[0034] In the load/unload unit 2, the wafer W is horizontally held
by either of the carrier arms 11a, 11b of the wafer carrier
mechanism 11, and when the wafer carrier mechanism 11 is driven,
the wafer W is rotated and moved straight in a substantially
horizontal plane or lifted up/down. Consequently, the wafer W is
carried to/from the carriers C, the orienter 15, and the particle
monitor 16 from/to later-described two load lock chamber 24.
[0035] At the center of the processing unit 3, a common carrier
chamber 21 formed in a substantially polygonal shape (for example,
a hexagonal shape) is provided. In the shown example, two COR
apparatuses 22 (the COR apparatuses 22a according to the first
embodiment of the present invention or the COR apparatuses 22b
according to the second embodiment of the present invention)
applying the COR processing to the wafer W, four epitaxial growth
apparatuses 23 applying the SiGe layer film forming processing to
the wafer W, and the two load lock chambers 24 which can be
evacuated are provided around the common carrier chamber 21.
Between the common carrier chamber 21 and the COR apparatuses 22
and between the common carrier chamber 21 and the epitaxial growth
apparatuses 23, openable/closable gate vales 25 are provided
respectively.
[0036] The two load lock chambers 24 are disposed between the
carrier chamber 12 of the load/unload unit 2 and the common carrier
chamber 21 of the processing unit 3, and the carrier chamber 12 of
the load/unload unit 2 and the common carrier chamber 21 of the
processing unit 3 are coupled to each other via the two load lock
chambers 24. Openable/closable gate valves 26 are provided between
the load lock chambers 24 and the carrier chamber 12 and between
the load lock chambers 24 and the common carrier chamber 21. One of
the two load lock chambers 24 may be used when the wafer W is
carried out of the carrier chamber 12 to be carried into the common
carrier chamber 21, and the other may be used when the wafer W is
carried out of the common carrier chamber 21 to be carried into the
carrier chamber 12.
[0037] A second wafer carrier mechanism 31 carrying the wafer W is
provided in the common carrier chamber 21. The wafer carrier
mechanism 31 has two carrier arms 31a, 31b each holding the wafer W
in a substantially horizontal state.
[0038] In such a common carrier chamber 21, the wafer W is
horizontally held by either of the carrier arms 31a, 31b, and when
the wafer carrier mechanism 31 is driven, the wafer W is rotated
and moved straight in a substantially horizontal plane or lifted
up/down to be carried to a desired position. Then, by the carrier
arms 31a, 31b entering and exiting from the load lock chambers 24,
the COR apparatuses 22, and the epitaxial growth apparatuses 23,
the wafers W are loaded/unloaded thereto/therefrom.
(Structure of COR Apparatus 22a According to First Embodiment)
[0039] FIG. 2 and FIG. 3 are explanatory views of the COR apparatus
22a according to the first embodiment of the present invention.
FIG. 2 shows a state where a cooling block 80 is raised. FIG. 3
shows a state where the cooling block 80 is lowered.
[0040] The COR apparatus 22a includes a casing 40, and the inside
of the casing 40 is an airtight process chamber (processing space)
41 housing the wafer W. The casing 40 is made of metal such as
aluminum (Al) or an aluminum alloy which has been surface-treated,
for instance, anodized. The casing 40 has on its one side surface a
load/unload port 42 through which the wafer W is loaded/unloaded
to/from the process chamber 41, and the aforesaid gate valve 25 is
provided on the load/unload port 42.
[0041] In the process chamber 41, a mounting table 45 is provided
to have the wafer W placed thereon in a substantially horizontal
state. The mounting table 45 is structured such that a face plate
47 as a support member supporting the wafer W is horizontally
attached on an upper surface of a cylindrical base portion 46
formed on a bottom surface of the casing 40. The face plate 47 is
in a disk shape slightly larger than the wafer W. Further, the face
plate 47 is made of a material excellent in heat transfer property,
and is made of, for example, SiC or AlN.
[0042] On an upper surface of the mounting table 45 (an upper
surface of the face plate 47), a plurality of abutting pins 48 as
abutting members abutting on a lower surface of the wafer W are
provided so as to protrude upward. The abutting pins 48 are made of
the same material as that of the face plate 47 or made of ceramics,
resin, or the like. The wafer W is supported substantially
horizontally on the upper surface of the mounting table 45 while a
plurality of points of its lower surface are set on upper end
portions of the abutting pins 48 respectively.
[0043] Further, around the wafer W, a lifter mechanism 50 is
provided to place the wafer W carried into the process chamber 41
on the upper surface of the mounting table 45 (the upper surface of
the face plate 47) and lift up the wafer W placed on the upper
surface of the mounting table from the mounting table 45. As shown
in FIG. 4, the lifter mechanism 50 is structured such that three
lifter pins 52 are attached to an inner side of a support member 51
in a substantially C shape disposed outside the wafer W. In FIG. 2
and FIG. 3, only the lifter pins 52 of the lifter mechanism 50 are
shown.
[0044] As shown in FIG. 4, the three lifter pins 52 support a lower
surface of a peripheral edge portion of the wafer W, and lines
connecting positions at which the lifter pins 52 support the wafer
W form an isosceles triangle (including an equilateral triangle).
In a case where the lines connecting the positions at which the
lifter pins 52 support the wafer W form an equilateral triangle as
an example, each center angle .theta. made by the lifter pins 52 is
120.degree.. The support member 51 is attached to an upper end of a
lifter rod 53 penetrating through the bottom surface of the casing
40. A lifter device 55 such as a cylinder disposed outside the
process chamber 41 is attached to a lower end of the lifter rod 53
via a bracket 56. Further, around the lifter rod 53, a bellows 57
is provided to allow the upward and downward movement of the lifter
rod 53 while keeping the inside of the process chamber 41
airtight.
[0045] The lifer mechanism 50 as structured above is capable of
lifting up/down the wafer W supported by the lifter pins 52 in the
process chamber 41 when the lifter device 55 is operated. When the
wafer W is carried into the COR apparatus 22a by either of the
carrier arms 31a, 31b of the aforesaid wafer carrier mechanism 31,
the lifter pins 52 of the lifter mechanism 50 move up to receive
the wafer W from the carrier arm 31a, 31b, and thereafter, the
lifter pins 52 move down to place the wafer W on the upper surface
of the mounting table 45 (the upper surface of the face plate 47).
Further, when the wafer W is to be carried out of the COR apparatus
22a, the lifter pins 52 first move up, so that the wafer W is
lifted up to a position above the mounting table 45 Thereafter,
either of the carrier arms 31a, 31b of the aforesaid wafer carrier
mechanism 31 receives the wafer W from the lifter pins 55 to carry
the wafer W out of the COR apparatus 22a.
[0046] FIG. 5 is an enlarged partial sectional view showing the
structure for attaching a peripheral edge portion of the face plate
47 to the upper surface of the base portion 46. A heat insulating
member 60 in a ring shape such as, for example, VESPEL (registered
trademark) is disposed between the upper surface of the base
portion 46 and a lower surface of the peripheral edge portion of
the face plate 47. Further, on an upper surface of the peripheral
edge portion of the face plate 47, a heat insulating member 61 in a
ring shape such as, for example, VESPEL (registered trademark) is
similarly disposed, and the face plate 47 is further pressed by a
fixing member 62 from above the insulating member 61, so that the
face plate 47 is fixed to the upper surface of the base portion 46.
The heat insulating members 60, 61 are thus disposed between the
peripheral edge portion of the face plate 47 and the upper surface
of the base portion 46 to thermally insulate the peripheral edge
portion of the face plate 47 and the upper surface of the base
portion 46 from each other.
[0047] Sealing members 63 such as O-rings are disposed between the
lower surface of the peripheral edge portion of the face plate 47
and the heat insulating member 60 and between the heat insulating
member 60 and the upper surface of the base portion 46. Therefore,
the inside of the process chamber 41, that is, an area above the
face plate 47, is kept airtightly closed relative to the outside of
the process chamber 41, that is, an area under the face plate 47.
On the other hand, the rear surface (lower surface) of the face
plate 47 is exposed to the outside of the process chamber 41 via
the inside of the base portion 46.
[0048] FIG. 6 is an enlarged partial sectional view showing the
structure for attaching the peripheral edge portion of the face
plate 47, which is different from the structure in FIG. 5. In this
attachment structure in FIG. 6, an upper gasket 65 in a ring shape,
a heat insulating member 66 in a ring shape such as, for example,
VESPEL (registered trademark), and a lower gasket 67 in a ring
shape are disposed between the lower surface of the peripheral edge
portion of the face plate 47 and the upper surface of the base
portion 46. A gap between the peripheral edge portion of the face
plate 47 and the upper gasket 65, a gap between the upper gasket 65
and the heat insulating member 66, and a gap between the heat
insulating member 66 and the lower gasket 67 are all sealed by
metal sealing structures. A sealing member 68 such as an O-ring is
provided between the lower gasket 67 and the upper surface of the
base portion 46. Therefore, the inside of the process chamber 41,
that is, an area above the face plate 47, is kept airtightly closed
relative to the outside of the process chamber 41, that is, an area
under the face plate 47.
[0049] A heat insulating member 70 in a ring shape such as, for
example, VESPEL (registered trademark) is further disposed on the
upper surface of the peripheral edge portion of the face plate 47,
and the face plate 47 is further pressed from above the heat
insulating member 70, so that the face plate 47 is fixed to the
upper surface of the base portion 46. In the attachment structure
in FIG. 6, a focus ring 72 is disposed around the wafer W placed on
the face plate 47. The attachment structure in FIG. 6 can also
maintain the heat insulation state between the peripheral edge
portion of the face plate 47 and the upper surface of the base
portion 46 while keeping the inside of the process chamber 41
airtight.
[0050] As shown in FIG. 2 and FIG. 3, a heater 75 as a second
temperature adjusting member is provided in close contact with a
rear surface (lower surface) of the face plate 47. The heater 75 is
made of a material having an excellent heat transfer property and
generating heat when supplied with electricity, and is made of, for
example, SiC. By the heat generated from the heater 75, it is
possible to heat the wafer W placed on the upper surface of the
face plate 47. The heater 75 has a disk shape substantially equal
in diameter to the wafer W, and by transferring the heat of the
heater 75 to the whole wafer W via the face plate 47, it is
possible to heat the whole wafer W uniformly.
[0051] The cooling block 80 as a first temperature adjusting member
is disposed under the heater 75. The cooling block 80 is disposed
on a rear surface (lower surface) side of the face plate 47, that
is, outside the process chamber 41. The cooling block 80 is movable
up/down by the operation of a lifter device 82 such as a cylinder
supported by a bracket 81 fixed to a lower surface of the casing
40, and a state where the cooling block 80 is moved up to be in
contact with the lower surface of the heater 75 (a state where the
cooling block 80 is in thermal contact with the face plate 47) as
shown in FIG. 2 and a state where the cooling block 80 is moved
down to be separated from the lower surface of the heater 75 (a
state where the face plate 47 is thermally separated from the face
plate 47) as shown in FIG. 3 are switched. The cooling block 80 has
a columnar shape substantially equal in diameter to the wafer W,
and the whole upper surface of the cooling block 80 comes into
contact with the rear surface of the heater 75 when the cooling
block 80 is moved up as shown in FIG. 2.
[0052] As shown in FIG. 7, a refrigerant channel 85 through which a
refrigerant, for example, a fluorine-based inert chemical solution
(Galden) flows is provided in the cooling block 80. By
circulatingly supplying the refrigerant to the refrigerant channel
85 from the outside of the casing 40 through a refrigerant feed
pipe 86 and a refrigerant drain pipe 87, it is possible to cool the
cooling block 80 to about 25.degree. C., for instance. The
refrigerant feed pipe 86 and the refrigerant drain pipe 87 are
formed of bellows, flexible tubes, or the like so that the feeding
of the refrigerant is not prevented when the cooling block 80 moves
up/down by the operation of the aforesaid lifter device 82.
[0053] A cushion plate 90 for bringing the cooling block 80 into
close contact with the lower surface of the heater 75 is provided
between the cooling block 80 and the lifter device 82.
Specifically, as shown in FIG. 7, a plurality of coil springs 91
are provided between the lower surface of the cooling block 80 and
an upper surface of the cushion plate 90, and the cooling block 80
can be inclined in a desired direction relative to the cushion
plate 90. Further, a lower surface of the cushion plate 90 is
connected to a piston rod 92 of the lifter device 82 via a floating
joint 93, so that the cushion plate 90 itself can also be inclined
in a desired direction relative to the piston rod 92. With this
structure, when the cooling block 80 is moved up by the operation
of the lifter device 82 as shown in FIG. 2, the upper surface of
the cooling block 80 comes into close contact with the whole lower
surface of the heater 75. By thus bringing the cooling block 80
into close contact with the lower surface of the heater 75, it is
possible to rapidly cool the wafer W placed on the upper surface of
the face plate 47. The cooling block 80 has a disk shape
substantially equal in diameter to the wafer W, and by transferring
the cold heat of the cooling block 80 to the whole wafer W via the
heater 75 and the face plate 47, it is possible to cool the whole
wafer W uniformly.
[0054] Total heat capacity of the face plate 47 and the heater 75
is set smaller than heat capacity of the cooling block 80.
Specifically, the aforesaid face plate 47 and heater 75 each have,
for example, a thin plate shape with relatively small heat capacity
and are made of a material excellent in heat transfer property such
as SiC. On the other hand, the cooling block 80 has a columnar
shape whose thickness is sufficiently larger than the total
thickness of the face plate 47 and the heater 75. Therefore, in the
state where the cooling block 80 is moved up to be in contact with
the lower surface of the heater 75 as shown in FIG. 2, it is
possible to rapidly cool the face plate 47 and the heater 75 by
transferring the heat of the cooling block 80 to the face plate 47
and the heater 75. This enables rapid cooling of the wafer W placed
on the upper surface of the face plate 47. On the other hand, in
the state where the cooling block 80 is moved down to be separated
from the lower surface of the heater 75 as shown in FIG. 3, the
face plate 47 and the heater 75 can be heated when the heater 75 is
supplied with electricity. In this case, the face plate 47 and the
heater 75 can be rapidly heated to a predetermined temperature
owing to their relatively small heat capacity, which enables rapid
heating of the wafer W placed on the upper surface of the face
plate 47.
[0055] As shown in FIG. 2 and FIG. 3, the COR apparatus 22a has a
gas supply mechanism 100 supplying predetermined gases into the
process chamber 41. The gas supply mechanism 100 includes an HF
supply path 101 through which hydrogen fluoride gas (HF) as the
process gas containing the halogen element is supplied into the
process chamber 41, an NH.sub.3 supply path 102 through which
ammonia gas (NH.sub.3) as the basic gas is supplied into the
process chamber 41, an Ar supply path 103 through which argon gas
(Ar) as inert gas is supplied into the process chamber 41, an
N.sub.2 supply path 104 through which nitrogen gas (N.sub.2) as
inert gas is supplied into the process chamber 41, and a showerhead
105. The HF supply path 101 is connected to a supply source 111 of
the hydrogen fluoride gas. Further, the HF supply path 101 has in
its middle a flow rate regulating valve 112 capable of
opening/closing the HF supply path 101 and adjusting a supply flow
rate of the hydrogen fluoride gas. The NH.sub.3 supply path 102 is
connected to a supply source 113 of the ammonia gas. Further, the
NH.sub.3 supply path 102 has in its middle a flow rate regulating
valve 114 capable of opening/closing the NH.sub.3 supply path 102
and adjusting a supply flow rate of the ammonia gas. The Ar supply
path 103 is connected to a supply source 115 of the argon gas.
Further, the Ar supply path 103 has in its middle a flow rate
regulating valve 116 capable of opening/closing the Ar supply path
103 and adjusting a supply flow rate of the argon gas. The N.sub.2
supply path 104 is connected to a supply source 117 of the nitrogen
gas. Further, the N.sub.2 supply path 104 has in its middle a flow
rate regulating valve 118 capable of opening/closing the N.sub.2
supply path 104 and adjusting a supply flow rate of the nitrogen
gas. The supply paths 101, 102, 103, 104 are connected to the
showerhead 105 provided in a ceiling portion of the process chamber
41, and the hydrogen fluoride gas, the ammonia gas, the argon gas,
and the nitrogen gas are diffusively jetted from the showerhead 105
into the process chamber 41.
[0056] In the COR apparatus 22a, an exhaust mechanism 121
exhausting the gas out of the process chamber 41 is provided. The
exhaust mechanism 121 includes an exhaust path 125 having in its
middle an opening/closing valve 122 and an exhaust pump 123 for
forced exhaust.
(Control Unit 4)
[0057] The functional elements of the processing system 1 and the
COR apparatuses 22a are connected via signal lines to the control
unit 4 automatically controlling the operation of the whole
processing system 1. Here, the functional elements refer to all the
elements which operate for realizing predetermined process
conditions, such as, for example, the first wafer carrier mechanism
11, the gate valves 14, 25, 26, and the second wafer carrier
mechanism 31 which are provided in the processing system 1, and the
lifter mechanism 50, the heater 75, the lifter device 82,
refrigerant supply to the cooling block 80, the gas supply
mechanism 100, the exhaust mechanism 121, and so on which are
provided in the COR apparatus 22a. The control unit 4 is typically
a general-purpose computer capable of realizing an arbitrary
function depending on software that it executes.
[0058] As shown in FIG. 1, the control unit 4 has an arithmetic
part 4a including a CPU (central processing unit), an input/output
part 4b connected to the arithmetic part 4a, and a storage medium
4c storing control software and inserted in the input/output part
4b. The control software (program) recorded in the storage medium
4c causes the processing system 1 and the COR apparatus 22a to
perform a predetermined substrate processing method to be described
later when executed by the control unit 4. By executing the control
software, the control unit 4 controls the functional elements of
the processing system 1 and the COR apparatus 22a so that various
process conditions (for example, pressure of the process chamber 41
and so on) defined by a predetermined process recipe are
realized.
[0059] The storage medium 4c may be the one fixedly provided in the
control unit 4, or may be the one removably inserted in a not-shown
reader provided in the control unit 4 and readable by the reader.
In the most typical embodiment, the storage medium 4c is a hard
disk drive in which the control software has been installed by a
serviceman of a maker of the processing system 1. In another
embodiment, the storage medium 4c is a removable disk such as
CD-ROM or DVD-ROM in which the control software is written. Such a
removable disk is read by an optical reader (not shown) provided in
the control unit 4. Further, the storage medium 4c may be either of
a RAM (random access memory) type or a ROM (read only memory) type.
Further, the storage medium 4c may be a cassette-type ROM. In
short, any medium known in a computer technical field is usable as
the storage medium 4c. In a factory where the plural processing
systems 1 are disposed, the control software may be stored in a
management computer centrally controlling the control units 4 of
the processing systems 1. In this case, each of the processing
systems 1 is operated by the management computer via a
communication line to execute a predetermined process.
(Processing of Wafer W in Processing System 1 Including COR
Apparatus 22a according to First Embodiment)
[0060] Next, a method of processing the wafer W using the
processing system 1 including the COR apparatus 22a according to
the first embodiment of the present invention will be described. To
begin with, the structure of the wafer W will be described. The
following will describe a case, as an example, where natural oxide
films 156 formed on the surface of the wafer W having undergone an
etching process are removed by the COR processing, and SiGe is
epitaxially grown on a surface of a Si layer 150. It should be
noted that the structure of the wafer W and the processing of the
wafer W described below are only an example, and the present
invention is not limited to the embodiment below.
[0061] FIG. 8 is a rough sectional view of the wafer W which has
not yet undergone the etching process, showing part of the surface
of the wafer W (device formation surface). The wafer W is, for
example, a thin-plate silicon wafer formed in a substantially disk
shape, and on the surface of the wafer W, formed is a structure
composed of the Si (silicon) layer 150 as a base material of the
wafer W, an oxide layer (silicon dioxide: SiO.sub.2) 151 used as an
interlayer insulation layer, a Poly-Si (polycrystalline silicon)
layer 152 used as a gate electrode, and, for example, TEOS
(tetraethylorthosiicate: Si(OC.sub.2H.sub.5).sub.4) layers 153 as
sidewall portions made of an insulator. A surface (upper surface)
of the Si layer 150 is substantially flat, and the oxide layer 151
is stacked to cover the surface of the Si layer 150. Further, the
oxide layer 151 is formed in, for example, a diffusion furnace
through a thermal CVD reaction. The Poly-Si layer 152 is formed on
a surface of the oxide layer 151 and is etched along a
predetermined pattern shape. Therefore, some portions of the oxide
layer 151 are covered by the Poly-Si layer 152, and other portions
thereof are exposed. The TEOS layers 153 are formed to cover side
surfaces of the Poly-Si layer 152. In the shown example, the
Poly-Si layer 152 has a substantially prismatic cross section and
is formed in a long and thin plate shape extending in a direction
from the near side toward the far side in FIG. 8, and the TEOS
layers 153 are provided on the right and left side surfaces of the
Poly-Si layer 12 to extend along the direction from the near side
toward the far side and to cover the Poly-Si layer 152 from its
lower edge to upper edge. On the right and left sides of the
Poly-Si layer 152 and the TEOS layers 153, the surface of the oxide
layer 151 is exposed.
[0062] FIG. 9 shows a state of the wafer W having undergone the
etching process. After the oxide layer 151, the Poly-Si layer 152,
the TEOS layers 153, and so on are formed on the Si layer 150 as
shown in FIG. 8, the wafer W is subjected to, for example, dry
etching. Consequently, as shown in FIG. 9, on the surface of the
wafer W, the exposed oxide layer 151 and the Si layer 150 covered
by the oxide layer 151 are partly removed. Specifically, on the
right and left sides of the Poly-Si layer 152 and the TEOS layers
153, recessed portions 155 are formed respectively by the etching.
The recessed portions 155 are formed so as to sink into the Si
layer 150 from the height of the surface of the oxide layer 151,
and the Si layer 150 is exposed on inner surfaces of the recessed
portions 155. However, if oxygen in the atmosphere adheres to the
surface of the Si layer 150 thus exposed in the recessed portions
155, the natural oxide films (silicon dioxide: SiO.sub.2) 156 are
formed on the inner surfaces of the recessed portions 155 since the
Si layer 150 is easily oxidized.
[0063] The wafer W thus subjected to the etching process by a dry
etching apparatus (not shown) or the like and having the natural
oxide films 156 formed on the inner surfaces of the recessed
portions 155 as shown in FIG. 9 is housed in the carrier C to be
carried to the processing system 1.
[0064] In the processing system 1, as shown in FIG. 1, the carrier
C housing the plural wafers W is placed on the mounting table 13,
and one of the wafers W is taken out of the carrier C by the wafer
carrier mechanism 11 to be carried into the load lock chamber 24.
When the wafer W is carried into the load lock chamber 24, the load
lock chamber 24 is airtightly closed and pressure-reduced.
Thereafter, the load lock chamber 24 and the common carrier chamber
21 whose pressure is reduced below the atmospheric pressure are
made to communicate with each other. Then, the wafer W is carried
out of the load lock chamber 24 to be carried into the common
carrier chamber 21 by the wafer carrier mechanism 31.
[0065] The wafer W carried into the common carrier chamber 21 is
first carried into the process chamber 41 of the COR apparatus 22a.
The wafer W is carried into the process chamber 41 of the COR
apparatus 22a by either of the carrier arms 31a, 31b of the wafer
carrier mechanism 31, with its surface (device formation surface)
facing upward. Then, the lifter pins 52 of the lifter mechanism 50
move up and receive the wafer W. Thereafter, the lifter pins 52
move down to place the wafer W on the upper surface of the mounting
table 45 (the upper surface of the face plate 47). After the
carrier arm 31a, 31b exits from the inside of the process chamber
41, the load/unload port 42 is closed to make the inside of the
process chamber 41 airtight. Incidentally, when the wafer W is thus
carried into the process chamber 41, the pressure of the process
chamber 41 has been reduced to a pressure close 5 to vacuum.
[0066] Then, the cooling block 80 is moved up by the operation of
the lifter device 82 as shown in FIG. 2 to bring the upper surface
of the cooling block 80 into close contact with the whole lower
surface of the heater 75. In this case, the cold heat of the
cooling block 80 cooled in advance by the refrigerant which is
circulatingly supplied to the refrigerant channel 85 is transferred
to the face plate 47 and the heater 75, so that the face plate 47
and the heater 75 can be rapidly cooled since the total heat
capacity of the face plate 47 and the heater 75 is smaller than the
heat capacity of the cooling block 80. Consequently, the wafer W
placed on the upper surface of the face plate 47 is cooled to, for
example, about 25.degree. C. Incidentally, in the state where the
cooling block 80 is thus moved up, the heat generation of the
heater 75 is not required.
[0067] Then, the hydrogen fluoride gas, the ammonia gas, the argon
gas, and the nitrogen gas are supplied into the process chamber 41
through the respective supply paths 101, 102, 103, 104, followed by
the chemical processing step for turning the natural oxide films
156 on the surface of the wafer W into the reaction products. In
this case, through forced exhaust of the inside of the process
chamber 41 by the exhaust mechanism 121, the pressure in the
process chamber 41 is reduced to about 0.1 Torr (about 13.3 Pa) or
lower, for instance. In such a low-pressure processing atmosphere,
the natural oxide films 156 existing on the surface of the wafer W
chemically react with molecules of the hydrogen fluoride gas and
molecules of the ammonia gas to be turned into the reaction
products.
[0068] When the chemical processing step is finished, the PHT step
(heat treatment step) is started. In the heat treatment step, the
cooling block 80 is moved down by the operation of the lifter
device 82 as shown in FIG. 3 to be separated from the lower surface
of the heater 75. Then, by the electricity supply to the heater 75,
the face plate 47 and the heater 75 are heated to, for example,
about 100.degree. C. or higher. In this case, the face plate 47 and
the heater 75 can be rapidly heated to the target temperature owing
to their relatively small heat capacity, which enables rapid
heating of the wafer W placed on the upper surface of the face
plate 47. Further, the inside of the process chamber 41 is forcedly
exhausted by the exhaust mechanism 121 along with the supply of the
argon gas and the nitrogen gas into the process chamber 41 through
the respective supply paths 103, 104, and reaction products 156'
produced by the above chemical processing step are heated and
vaporized to be removed from the inner surfaces of the recessed
portions 155. Through the above processes, the surface of the Si
layer 150 is exposed (see FIG. 10). Such a heat treatment step
following the chemical processing step makes it possible to
dry-clean the wafer W and remove the natural oxide films 156 from
the Si layer 150 by dry etching.
[0069] When the COR processing including the chemical processing
step and the heat treatment step is thus finished, the supply of
the argon gas and the nitrogen gas is stopped and the load/unload
port 42 (gate valve 25) of the COR apparatus 22a is opened.
Thereafter, the wafer W is carried out of the process chamber 41 by
the wafer carrier mechanism 31 to be carried into the epitaxial
growth apparatus 23.
[0070] When the wafer W with the surface of the Si layer 150 being
exposed by the COR processing is thus carried into the epitaxial
growth apparatus 23, the SiGe film forming processing step is then
started. In the film forming processing step, reaction gas supplied
to the epitaxial growth apparatus 23 and the Si layer 150 exposed
in the recessed portions 155 of the wafer W chemically react with
each other, so that SiGe layers 160 are epitaxially grown on the
recessed portions 155 (see FIG. 11). Here, since the natural oxide
films 156 have been removed by the aforesaid COR processing from
the surface of the Si layer 150 exposed in the recessed portions
155, the SiGe layers 160 are suitably grown with the surface of the
Si layer 150 serving as their base.
[0071] When the SiGe layers 160 are thus formed on the recessed
portions 155 on the both sides, a portion of the Si layer 150
sandwiched by the SiGe layers 160 is given a compressive stress
from both sides. That is, under the Poly-Si layer 152 and the oxide
layer 151, a strained Si layer 150' having a compressive strain is
formed in the portion sandwiched by the SiGe layers 160.
[0072] When the SiGe layers 160 are thus formed, that is, when the
film forming processing step is finished, the wafer W is carried
out of the epitaxial growth apparatus 23 by the wafer carrier
mechanism 31 to be carried into the load lock chamber 24. When the
wafer W is carried into the load lock chamber 24, the load lock
chamber 24 is airtightly closed and thereafter the load lock
chamber 24 and the carrier chamber 12 are made to communicate with
each other. Then, the wafer W is carried out of the load lock
chamber 24 to be returned to the carrier C on the mounting table 13
by the wafer carrier mechanism 11. In the above-described manner, a
series of processes in the processing system 1 is finished.
[0073] In such a COR apparatus 22a according to the first
embodiment of the present invention, it is possible to rapidly cool
the wafer W placed on the upper surface of the face plate 47 by
bringing the cooling block 80 as the first temperature adjusting
member into thermal contact with the face plate 47 as the support
member. Further, when the cooling block 80 is separated from the
face plate 47, the wafer W placed on the upper surface of the face
plate 47 can be rapidly heated by the heat generated from the
heater 75 as the second temperature adjusting member. This enables
rapid heat treatment of the wafer W, which can shorten the
processing time to improve a throughput. Further, since the wafer W
can be COR-processed in the same process chamber 41, the COR
apparatus 22a can be compact and a complicated transfer sequence
for transferring the wafer W is not required.
[0074] Further, since the cooling block 80 is disposed outside the
pressure-reduced process chamber 41 and comes into thermal contact
with the rear surface (lower surface) side of the face plate 47,
the cooling block 80 is prevented from coming into a so-called
vacuum heat insulation state and thus is capable of efficiently
cooling the face plate 47. In this case, since the cooling block 80
is supported via the cushion plate 90 and the coil springs 91, the
whole upper surface of the cooling block 80 can be in contact with
the rear surface of the heater 75, which makes it possible to cool
the whole face plate 47 to uniformly cool the wafer W.
(Structure of COR Apparatus 22b According to Second Embodiment)
[0075] Next, the COR apparatus 22b according to the second
embodiment of the present invention will be described. FIG. 12 and
FIG. 13 are explanatory views of the COR apparatus 22b according to
the second embodiment of the present invention. FIG. 12 shows a
state where the wafer W is placed on a mounting table 245 (first
processing position). FIG. 13 shows a state where the wafer W is
lifted up from the mounting table 245 (second processing
position).
[0076] The COR apparatus 22b includes a casing 240, and the inside
of the casing 240 is an airtight process chamber (processing space)
241 housing the wafer W. The casing 240 is made of metal such as
aluminum (Al) or an aluminum alloy which has been surface-treated,
for instance, anodized. The casing 240 has on its one side surface
a load/unload port 242 through which the wafer W is loaded/unloaded
to/from the process chamber 241, and the aforesaid gate valve 25 is
provided on the load/unload port 242.
[0077] On a bottom of the process chamber 241, a mounting table 245
is provided to have the wafer W placed thereon in a substantially
horizontal state. The mounting table 245 functions as a first
temperature adjusting member temperature-adjusting the wafer W
placed on the mounting table 245. The mounting table 245 has a
columnar shape substantially equal in diameter to the wafer W and
is made of a material excellent in heat transfer property, for
example, metal such as aluminum (Al) or an aluminum alloy.
[0078] On an upper surface of the mounting table 245, a plurality
of abutting pins 246 as abutting members abutting on a lower
surface of the wafer W are provided so as to protrude upward. The
abutting pins 246 are made of the same material as that of the
mounting table 245 or made of ceramics, resin, or the like. The
wafer W is supported substantially horizontally on the upper
surface of the mounting table 245 while a plurality of points of
its lower surface are set on upper end portions of the abutting
pins 246 respectively. For convenience of the description, the
position (height) of the wafer W placed on the upper surface of the
mounting table 245 as shown in FIG. 12 is defined as a "first
processing position".
[0079] In the mounting table 245, a refrigerant channel 250 is
provided. By circulatingly supplying a refrigerant to the
refrigerant channel 250 from the outside of the casing 240 through
a refrigerant feed pipe 251 and a refrigerant drain pipe 252, it is
possible to cool the mounting table 245 to about 25.degree. C., for
instance, and to cool the wafer W placed on the mounting table 245.
A refrigerant such as, for example, a fluorine-based inert chemical
solution (Galden) is supplied to the refrigerant channel 250.
[0080] In the mounting table 245, lifter pins 255 are provided
which receive/deliver the wafer W from/to either of the carrier
arms 31a, 31b of the aforesaid wafer carrier mechanism 31 when the
wafer W is loaded/unloaded. The lifter pins 255 move up/down by the
operation of a cylinder device 256 disposed outside the casing 240.
When the wafer W is carried into the COR apparatus 22b by either of
the carrier arms 31a, 31b of the aforesaid wafer carrier mechanism
31, the lifter pins 255 move up so that the upper ends thereof
reach the height of the load/unload port 242 as shown by the dashed
line in FIG. 12, to receive the wafer W from the carrier arm 31a,
31b, and thereafter, the lifter pins 255 move down, so that the
wafer W is placed on the upper surface of the mounting table 245.
Further, when the wafer W is carried out of the COR apparatus 22b,
the lifter pins 255 first move up, so that the wafer W is lifted up
to the height of the load/unload port 242 as shown by the dashed
line in FIG. 12. Thereafter, either of the carrier arms 31a, 31b of
the aforesaid wafer carrier mechanism 31 receives the wafer W from
the lifter pins 255 to carry the wafer W out of the COR apparatus
22b. For convenience of the description, the position (height) of
the wafer W lifted up to the height of the load/unload port 242 by
the lifter pins 255 as shown by the dashed line in FIG. 12 is
defined as a "load/unload position".
[0081] Further, around the wafer W, a lifter mechanism 260 is
provided to lift the wafer W placed on the upper surface of the
mounting table 245 up to a position still higher than the aforesaid
load/unload position. The lifter mechanism 260 is structured such
that a ring-shaped support member 261 surrounding an outer side of
the wafer W is attached via a bracket 264 to an upper end of a
piston rod 263 of the cylinder device 262 disposed outside the
casing 240. By the extension/contraction operation of the cylinder
device 262, it is possible to change between the state where the
wafer W is placed on the mounting table 245 as shown in FIG. 12 and
the state where the wafer W is lifted up from the mounting table
245 as shown in FIG. 13. Around the piston rod 263, a bellows 265
is attached to allow the upward/downward movement of the piston rod
263 while keeping the inside of the process chamber 241
airtight.
[0082] On an inner side of an upper surface of the support member
261, a stepped portion 261' capable of housing an outer edge
portion of the lower surface of the wafer W is formed, and when the
piston rod 263 is extended by the operation of the cylinder device
262, the wafer W is lifted up to the position still higher than the
load/unload position while the outer edge portion of the lower
surface of the wafer W is housed in the stepped portion 261' of the
support member 261, as shown in FIG. 13. For convenience of the
description, the position (height) of the wafer W lifted up from
the upper surface of the mounting table 245 by the lifter mechanism
260 as shown in FIG. 13 is defined as a "second processing
position".
[0083] On the other hand, when the piston rod 263 is contracted by
the operation of the cylinder device 262, the stepped portion 261'
of the support member 261 moves down to a position slightly lower
than the upper ends of the abutting pins 246 on the upper surface
of the mounting table 245, so that the wafer W comes to be
supported by the abutting pins 246 on the upper surface of the
mounting table 245 (first processing position).
[0084] Around the wafer W lifted up to the second processing
position by the lifter mechanism 260 as shown in FIG. 13, a
partition member 270 is disposed. The partition member 270 is fixed
to an inner peripheral surface of the casing 240 and is
horizontally disposed so as to partition an area around the support
member 261 which has been lifted up to the second processing
position while the outer edge portion of the lower surface of the
wafer W is housed in the stepped portion 261'. The partition member
270 is made of a heat insulating material such as, for example,
VESPEL (registered trademark). When the wafer W is lifted up to the
second processing position by the lifter mechanism 260 as shown in
FIG. 13, the wafer W, the support member 261, and the partition
member 270 partition the inside of the process chamber 241 into a
space 241 a above the wafer W and a space 241b under the wafer
W.
[0085] Above the partition member 270, the casing 240 has, on its
side surface, a transparent window portion 271. Further, a lamp
heater 272 as a second temperature adjusting member is disposed on
an outer side of the window portion 271 to emit infrared rays from
the outside of the process chamber 241 into the process chamber 241
through the window portion 271. As will be described later, when
the wafer W is lifted up to the second processing position by the
lifter mechanism 260, the infrared rays are emitted into the
process chamber 241 from the lamp heater 272 through the window
portion 271, so that the wafer W at the second processing position
is heated.
[0086] A gas supply mechanism 280 supplying predetermined gases
into the process chamber 241 is provided. The gas supply mechanism
280 includes an HF supply path 281 through which hydrogen fluoride
gas (HF) as the process gas containing the halogen element is
supplied into the process chamber 241, an NH.sub.3 supply path 282
through which ammonia gas (NH.sub.3) as the basic gas is supplied
into the process chamber 241, an Ar supply path 283 through which
argon gas (Ar) as inert gas is supplied into the process chamber
241, an N.sub.2 supply path 284 through which nitrogen gas
(N.sub.2) as inert gas is supplied into the process chamber 241,
and a showerhead 285. The HF supply path 281 is connected to a
supply source 291 of the hydrogen fluoride gas. Further, the HF
supply path 281 has in its middle a flow rate regulating valve 292
capable of opening/closing the HF supply path 281 and adjusting a
supply flow rate of the hydrogen fluoride gas. The NH.sub.3 supply
path 282 is connected to a supply source 293 of the ammonia gas.
Further, the NH.sub.3 supply path 282 has in its middle a flow rate
regulating valve 294 capable of opening/closing the ammonia supply
path 282 and adjusting a supply flow rate of the ammonia gas. The
Ar supply path 283 is connected to a supply source 295 of the argon
gas. Further, the Ar supply path 283 has in its middle a flow rate
regulating valve 296 capable of opening/closing the Ar supply path
283 and adjusting a supply flow rate of the argon gas. The N.sub.2
supply path 284 is connected to a supply source 297 of the nitrogen
gas. Further, the N.sub.2 supply path 284 has in its middle a flow
rate regulating valve 298 capable of opening/closing the N.sub.2
supply path 284 and adjusting a supply flow rate of the nitrogen
gas. The supply paths 281, 282, 283, 284 are connected to the
showerhead 285 provided in a ceiling portion of the process chamber
241, and the hydrogen fluoride gas, the ammonia gas, the argon gas,
and the nitrogen gas are difusively jetted from the showerhead 285
into the process chamber 241.
[0087] In the COR apparatus 22b, provided are: a first exhaust
mechanism 300 exhausting the inside of the process chamber 241
under the aforesaid partition member 270; and a second exhaust
mechanism 301 exhausting the inside of the process chamber 241
above the partition member 270. The first exhaust mechanism 300
includes an exhaust path 304 having in its middle an
opening/closing valve 302 and an exhaust pump 303 for forced
exhaust. An upstream end portion of the exhaust path 304 is opened
at a bottom surface of the casing 240. The second exhaust mechanism
301 includes an exhaust path 307 having in its middle an
opening/closing valve 305 and an exhaust pump 306 for forced
exhaust. An upstream end portion of the exhaust path 307 is opened
at a side surface of the casing 240 above the partition member
270.
[0088] In the case of the processing system 1 including the COR
apparatuses 22b, the functional elements controlled by the control
unit 4 refer to all the elements which operate for realizing
predetermined process conditions, for example, the first wafer
carrier mechanism 11, the gate valves 14, 25, 26, and the second
wafer carrier mechanism 31 which are provided in the processing
system 1, and refrigerant supply to the mounting table 245, the
cylinder device 256, the lifter mechanism 260, the lamp heater 272,
the gas supply mechanism 280, the exhaust mechanisms 300, 301, and
so on which are provided in the COR apparatus 22b.
(Processing of Wafer W in Processing System 1 Including COR
Apparatus 22b According to Second Embodiment)
[0089] Next, a method of processing the wafer W using the
processing system 1 including the COR apparatus 22b according to
the second embodiment of the present invention will be described.
Similarly to the above description, the following will describe a
case, as an example, where natural oxide films 156 formed on the
surface of the wafer W having undergone an etching process are
removed by the COR processing, and SiGe is epitaxially grown on a
surface of a Si layer 150.
[0090] In the processing system 1, as shown in FIG. 1, the carrier
C housing the plural wafers W is placed on the mounting table 13,
and one of the wafers W is taken out of the carrier C by the wafer
carrier mechanism 11 to be carried into the load lock chamber 24.
When the wafer W is carried into the load lock chamber 24, the load
lock chamber 24 is airtightly closed and pressure-reduced.
Thereafter, the load lock chamber 24 and the common carrier chamber
21 whose pressure is reduced below the atmospheric pressure are
made to communicate with each other. Then, the wafer W is carried
out of the load lock chamber 24 to be carried into the common
carrier chamber 21 by the wafer carrier mechanism 31.
[0091] The wafer W carried into the common carrier chamber 21 is
first carried into the process chamber 241 of the COR apparatus
22b. The wafer W is carried into the process chamber 241 of the COR
apparatus 22b by either of the carrier arms 31a, 31b of the wafer
carrier mechanism 31, with its surface (device formation surface)
facing upward. Then, the lifter pins 255 move up and receive the
wafer W from the carrier arm 31a, 31b which has lifted up the wafer
W to the load/unload position. Thereafter, the lifter pins 255 move
down to place the wafer W on the upper surface of the mounting
table 245, so that the wafer W is moved to the first processing
position as shown in FIG. 12.
[0092] After the carrier arm 31a, 31b exits from the inside of the
process chamber 241, the load/unload port 242 is closed to make the
inside of the process chamber 241 airtight. Incidentally, when the
wafer W is thus carried into the process chamber 241, the support
member 261 is in a lowered s state. Further, the pressure of the
process chamber 241 has been reduced to a pressure close to vacuum
(for example, several Torr to several tens Torr) by both of the
exhaust mechanisms 300, 301 or one of the exhaust mechanisms 300,
301.
[0093] Then, the refrigerant is circulatingly supplied to the
refrigerant channel 250 through the refrigerant feed pipe 251 and
the refrigerant drain pipe 252 to cool the mounting table 245 to
about 25.degree. C., for instance. In this manner, the wafer W
placed on the mounting table 245 is cooled to about 25.degree. C.,
for instance. In this case, by starting the supply of the
refrigerant before the wafer W is placed on the mounting table 245,
it is possible to cool the wafer W to a target temperature
immediately after the wafer W is placed on the upper surface of the
mounting table 245.
[0094] Then, the hydrogen fluoride gas, the ammonia gas, the argon
gas, and the nitrogen gas are supplied into the process chamber 241
through the respective supply paths 281, 282, 283, 284, and the
wafer W at the first processing position is subjected to the
chemical processing step for turning the natural oxide films 156 on
the surface of the wafer W into the reaction products. In this
case, through forced exhaust of the inside of the process chamber
241 by both of the exhaust mechanisms 300, 301 or one of the
exhaust mechanisms 300, 301, the pressure in the process chamber
241 is reduced to about several tens mTorr to about several Torr,
for instance. In such a low-pressure processing atmosphere, the
natural oxide films 156 existing on the surface of the wafer W
chemically react with molecules of the hydrogen fluoride gas and
molecules of the ammonia gas to be turned into the reaction
products.
[0095] When the chemical processing step is finished, the supply of
the hydrogen fluoride gas and the ammonia gas through the supply
paths 281, 282 is stopped. Incidentally, the supply of the argon
gas and the nitrogen gas through the supply paths 283, 284 may be
stopped at the same time, but the supply of the argon gas and the
nitrogen gas into the process chamber 241 through the supply paths
283, 284 may be continued even after the chemical processing step
is finished.
[0096] Then, the wafer W is moved from the first processing
position to the second processing position. Specifically, the
piston rod 263 is extended by the operation of the cylinder device
262 of the lifter mechanism 260, so that the wafer W is lifted up
to the second processing position while the outer edge portion of
the lower surface of the wafer W is housed in the stepped portion
261' of the support member 261 as shown in FIG. 13. Consequently,
the wafer W, the support member 261, and the partition member 270
partition the inside of the process chamber 241 into a space 241a
above the wafer W and a space 241b under the wafer W. Incidentally,
during this transfer of the wafer W from the first processing
position to the second processing position, the inside of the
process chamber 241 is also forcedly exhausted by both of the
exhaust mechanisms 300, 301 or one of the exhaust mechanisms 300,
301 so that the pressure in the process chamber 241 is reduced to
about several tens mTorr to about several Torr, for instance.
[0097] Next, the PHT step (heat treatment step) is started. In this
heat treatment step, the infrared rays are emitted from the lamp
heater 272 into the process chamber 241 through the window portion
271 to heat the wafer W at the second processing position to a
temperature equal to or higher than about 100.degree. C., for
instance. In this case, the wafer W can be rapidly heated to the
target temperature since heat capacity of the wafer W itself is
relatively small. Incidentally, the emission of the infrared rays
by the lamp heater 272 may be started before the wafer W is moved
to the second processing position.
[0098] Further, during the heat treatment, the upper space 241a in
the process chamber 241 is forcedly exhausted by the exhaust
mechanism 301 while the argon gas and the nitrogen gas are supplied
into the process chamber 241 through the supply paths 283, 284, and
reaction products 156' produced by the aforesaid chemical
processing are heated and vaporized to be removed from the inner
surfaces of the recessed portions 155. In this case, since the
inside of the process chamber 241 is partitioned by the wafer W,
the support member 261, and the partition member 270 into the upper
space 241a and the lower space 241b, the pressure of the upper
space 241a is reduced to about several Torr to about several tens
Torr, for instance, and the pressure of the lower space 241b is
reduced to about several hundreds mTorr to about several Torr, for
instance.
[0099] Through the above processes, the surface of the Si layer 150
is exposed by the heat treatment (see FIG. 10). Such heat treatment
following the chemical processing makes it possible to dry-clean
the wafer W and remove the natural oxide films 156 from the Si
layer 150 by dry-etching.
[0100] When the COR processing including the chemical processing
and the heat treatment is finished, the supply of the argon gas and
the nitrogen gas is stopped and the load/unload port 242 (gate
valve 25) of the COR apparatus 22b is opened. Incidentally, the
supply of the argon gas and the nitrogen gas into the process
chamber 241 through the supply paths 283, 284 may be continued even
after the COR processing is finished.
[0101] When the COR processing is finished, the lifter pins 255
move up from the mounting table 245, and the piston rod 263 is
contracted by the operation of the cylinder device 262 of the
lifter mechanism 260, so that the wafer W is moved down from the
second processing position. Then, the wafer W is delivered to the
lifter pins 255 from the support member 261 on its way downward.
Thus, the wafer W is moved to the load/unload position.
[0102] Thereafter, the wafer W is carried out of the process
chamber 241 by the wafer carrier mechanism 31, and then carried
into the epitaxial growth apparatus 23. Incidentally, when the
wafer W is carried out of the process chamber 241, the supply of
the argon gas and the nitrogen gas into the process chamber 241
through the supply paths 283, 284 may be continued and the inside
of the process chamber 241 may be forcedly exhausted by both of the
exhaust mechanisms 300, 301 or one of the exhaust mechanisms 300,
301 so that the pressure in the process chamber 241 is reduced to
about several Torr to about several tens Torr, for instance.
[0103] When the wafer W with the surface of the Si layer 150 being
exposed by the COR processing is thus carried into the epitaxial
growth apparatus 23, the SiGe film forming processing is then
started. In the film forming processing, reaction gas supplied to
the epitaxial growth apparatus 23 and the Si layer 150 exposed in
the recessed portions 155 of the wafer W chemically react with each
other, so that SiGe layers 160 are epitaxially grown on the
recessed portions 155 (see FIG. 11). Here, since the natural oxide
films 156 have been removed by the aforesaid COR processing from
the surface of the Si layer 150 exposed in the recessed portions
155, the SiGe layers 160 are suitably grown with the surface of the
Si layer 150 serving as their base.
[0104] When the SiGe layers 160 are thus formed on the recessed
portions 155 on the both sides, a portion of the Si layer 150
sandwiched by the SiGe layers 160 is given a compressive stress
from both sides. That is, under the Poly-Si layer 152 and the oxide
layer 151, a strained Si layer 150' having a compressive strain is
formed in the portion sandwiched by the SiGe layers 160.
[0105] When the SiGe layers 160 are thus formed, that is, when the
film forming processing is finished, the wafer W is carried out of
the epitaxial growth apparatus 23 by the wafer carrier mechanism 31
to be carried into the load lock chamber 24. When the wafer W is
carried into the load lock chamber 24, the load lock chamber 24 is
airtightly closed and thereafter the load lock chamber 24 and the
carrier chamber 12 are made to communicate with each other. Then,
the wafer W is carried out of the load lock chamber 24 to be
returned to the carrier C on the mounting table 13 by the wafer
carrier mechanism 11. In the above-described manner, a series of
processes in the processing system 1 is finished.
[0106] According to the COR apparatus 22b according to the second
embodiment of the present invention, in the process chamber 241,
the wafer W can be cooled and chemically processed on the mounting
table 245 when it is at the first processing position, and the
wafer W can be heated by the lamp heater 272 and heat-treated when
it is at the second processing position. By thus moving the wafer W
to the first processing position and to the second processing
position in the process chamber 241, it is possible to rapidly heat
and cool the wafer W. This enables rapid heat treatment, which can
shorten the processing time to improve a throughput. Further, since
the wafer W can be COR-processed in the same process chamber 241,
the COR apparatus 22b can be compact and a complicated transfer
sequence for transferring the wafer W is not required.
[0107] Further, during the heat treatment, the inside of the
process chamber 241 is partitioned into the space 241a above the
wafer W and the space 241b under the wafer W, and consequently,
heat by the lamp heater 272 is not easily transferred to the lower
space 241b, which can prevent a temperature increase of the
mounting table 245 set in a lower area (an area under the partition
member 270) in the process chamber 241. Accordingly, the mounting
table 245 is kept in a state where it can easily cool the wafer W
placed thereon next. In this case, if the partition member 270 is
made of a heat insulating material, it is possible to more
effectively prevent the temperature increase of the mounting table
245.
[0108] Since the upper space 241a in the process chamber 241 is
forcedly exhausted by the exhaust mechanism 301 during the heat
treatment, vapor of the reaction products 156' vaporized from the
surface of the wafer W can be discharged without entering the lower
space 241b, which can prevent the reaction products 156' from
adhering again to a rear surface of the wafer W and the lower area
in the process chamber 241 (the area under the partition member
270). In this case, the upper area in the process chamber 241 (the
area above the partition member 270) becomes higher in temperature
than the lower area in the process chamber 241 since the upper area
is heated by the lamp heater 272, and therefore the reaction
products 156' are difficult to adhere to the upper area.
Accordingly, the reaction products 156' do not easily adhere to the
entire process chamber 241, which makes it possible to keep the
inside of the process chamber 241 clean.
[0109] In the foregoing, preferred embodiments of the present
invention are described, but the present invention is not limited
to such examples. It is obvious that those skilled in the art could
think of various modified examples and corrected examples within a
range of the technical idea described in the claims, and it is
understood that such examples naturally belong to the technical
scope of the present invention.
[0110] In the COR apparatus 22a according to the first embodiment,
the rear surface of the face plate 47 is covered by the heater 75
so that the cold heat of the cooling block 80 is transferred to the
face plate 47 via the heater 75, but the cooling block 80 may come
into direct contact with the face plate 47. As shown in FIG. 14,
for instance, in the rear surface of the face plate 47 as the
support member, grooves may be provided in which heaters 75 as the
first temperature adjusting members are buried, thereby allowing
the cooling block 80 as the second temperature adjusting member to
come into direct contact with the lower surface of the face plate
47. In this case, the heaters 75 are held with, for example, a
metallized stud of the face plate 47 or an adhesive. By the cooling
block 80 thus coming into direct contact with the face plate 47,
more rapid cooling is possible. Further, depending on the depth and
width of the grooves, the contact area of the heaters 75 and the
face plate 47 can be increased, which can realize more rapid
temperature increase. Further, for improved heat transfer
efficiency to the face plate 47, the upper surface of the cooling
block 80 may be coated with grease, gelatinous substance, or the
like high in heat transfer property. Further, a sheet or the like
with a high heat transfer property may be provided on the upper
surface of the cooling block 80. Further, for decreased thermal
resistance between the heaters 75 and the face plate 47, a filler
such as an adhesive or a heat transfer material may be provided
between the heaters 75 and the face plate 47.
[0111] In the COR apparatus 22b according to the second embodiment,
the mounting table 245 including the refrigerant channel 250 is
shown as an example of the first temperature adjusting member, and
the lamp heater 272 is shown as an example of the second
temperature adjusting member. However, as these first and second
temperature adjusting mechanisms, any temperature adjusting
mechanisms capable of heating or cooling can be used. In
particular, the second temperature adjusting mechanism may be a
heating mechanism provided in the middle of the N.sub.2 supply path
284 in order to increase the temperature of the nitrogen gas. The
nitrogen gas whose temperature has been increased may be jetted to
the upper space 241a of the process chamber 241 from the showerhead
285 to heat the wafer W. Further, a heating mechanism may be
provided in the Ar supply path 283. Further, the wafer W may be
heated by the combination of the lamp heater 272 described in the
above embodiment and the above heating mechanism.
* * * * *