U.S. patent application number 11/623931 was filed with the patent office on 2007-05-24 for substrate processing method and substrate processing apparatus.
Invention is credited to Akira Izumi, Katsuhiko Miya.
Application Number | 20070113874 11/623931 |
Document ID | / |
Family ID | 29217986 |
Filed Date | 2007-05-24 |
United States Patent
Application |
20070113874 |
Kind Code |
A1 |
Izumi; Akira ; et
al. |
May 24, 2007 |
SUBSTRATE PROCESSING METHOD AND SUBSTRATE PROCESSING APPARATUS
Abstract
Disclosed is a substrate processing method including a substrate
rotating step for rotating a substrate with the substrate held
almost horizontally within a chamber; a peripheral edge processing
step for discharging a processing liquid to a lower surface of the
substrate rotated in the substrate rotating step and causing the
processing liquid to flow around an upper surface of the substrate
at a peripheral edge thereof from the lower surface of the
substrate to process the peripheral edge of the upper surface of
the substrate in the chamber; and a both-surface processing step
for discharging the processing liquid to both the surfaces of the
substrate rotated in the substrate rotating step to process both
the surfaces of the substrate in the chamber.
Inventors: |
Izumi; Akira; (Kyoto,
JP) ; Miya; Katsuhiko; (Kyoto, JP) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
US
|
Family ID: |
29217986 |
Appl. No.: |
11/623931 |
Filed: |
January 17, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10413608 |
Apr 14, 2003 |
7182821 |
|
|
11623931 |
Jan 17, 2007 |
|
|
|
Current U.S.
Class: |
134/33 ;
156/345.1; 257/E21.228 |
Current CPC
Class: |
Y10S 438/906 20130101;
H01L 21/6708 20130101; B08B 3/08 20130101; H01L 21/02052
20130101 |
Class at
Publication: |
134/033 ;
156/345.1 |
International
Class: |
B08B 7/00 20060101
B08B007/00; H01L 21/306 20060101 H01L021/306 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 19, 2002 |
JP |
2002-118129 |
Feb 25, 2003 |
JP |
2003-047855 |
Claims
1-3. (canceled)
4. The substrate processing method comprising: a substrate rotating
step for rotating a substrate with the substrate held almost
horizontally within a chamber; a peripheral edge processing step
for discharging a processing liquid to a lower main surface of the
substrate rotated in the substrate rotating step and causing the
processing liquid to flow around to an upper main surface of the
substrate at a peripheral edge thereof around a peripheral end
surface of the substrate which is defined between the upper surface
and the lower surface of the substrate, to process the peripheral
edge of the upper surface of the substrate in the chamber; and a
both-surface processing step for discharging a processing liquid to
both the main surfaces of the substrate rotated in the substrate
rotating step to process both the main surfaces of the substrate in
the chamber; wherein the both-surface processing step comprises a
pre-cleaning step for discharging a cleaning liquid to both the
main surfaces of the substrate rotated in the substrate rotating
step to clean the substrate before the peripheral edge processing
step.
5-10. (canceled)
11. The substrate processing method according to claim 4, wherein
the substrate processed in the peripheral edge processing step and
the both-surface processing step has a metal thin film formed on
one of its main surfaces and its end surface.
12. The substrate processing method according to claim 4, wherein
the cleaning liquid used in the pre-cleaning step is a particle
removing liquid for removing particles adhering to the surface of
the substrate.
13. The substrate processing method according to claim 4, wherein
the cleaning liquid used in the pre-cleaning step is a mixed
solution of aqueous ammonia, hydrogen peroxide and water.
14. The substrate processing method according to claim 4, wherein
the processing liquid used in the peripheral edge processing step
is an etchant.
15. The substrate processing method according to claim 4, wherein
the both-surface processing step comprises a post-cleaning step for
discharging a cleaning liquid to both the main surfaces of the
substrate rotated in the substrate rotating step to clean both the
main surfaces of the substrate after the peripheral edge processing
step.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a substrate processing
method and a substrate processing apparatus, in which a peripheral
edge of a substrate such as a substrate for a semiconductor wafer,
a substrate for an optical disk, a substrate for a magnetic disk,
or a substrate for a magnetooptic disk can be subjected to
processing using a processing liquid.
[0003] 2. Description of the Related Art
[0004] In the steps of manufacturing a semiconductor device,
so-called bevel etching for rotating a semiconductor wafer
(hereinafter merely referred to as "wafer") having a thin film
formed on its one surface with the wafer held approximately
horizontally, supplying an etchant to the other surface of the
wafer, and causing a part of the etchant to flow around to the one
surface at a peripheral edge of the wafer to etch a peripheral edge
of the thin film is carried out.
[0005] FIGS. 11 (a), 11 (b), and 11 (c) are schematic
cross-sectional views for explaining a conventional method of bevel
etching.
[0006] A wafer W to be processed has a thin film F such as a metal
film, for example, formed from its one surface to its end surface
(peripheral surface), and particles P produced at the time of
forming the thin film F adhere to a surface of the thin film F.
[0007] First, the wafer W is held approximately horizontally with
the surface on which the thin film F is formed directed upward, and
is rotated around its central axis C. An etchant L is discharged
toward the vicinity of the center of a lower surface of the wafer
W. The etchant L expands along the lower surface of the wafer W by
a centrifugal force caused by the rotation of the wafer W, to be
spun off sideward at a peripheral edge of the wafer W. Each of the
surfaces of the wafer W and the thin film F has a wettability with
the etchant L. Accordingly, a part of the etchant L flows around to
the upper surface of the wafer W at the peripheral edge thereof
(see FIG. 11 (a)). Consequently, the thin film F on the end surface
of the wafer W and at the peripheral edge of the upper surface
thereof is etched away.
[0008] Thereafter, deionized water D is supplied from the center of
the lower surface of the wafer W, thereby cleaning the lower
surface of the wafer W. At this time, a part of the deionized water
D flows around to the peripheral edge of the upper surface of the
wafer W as at the time of etching (see FIG. 11 (c)). Consequently,
the end surface of the wafer W and the peripheral edge of the upper
surface thereof are also cleaned.
[0009] However, the following problems occur in such a method.
[0010] The first problem is that contaminants caused by processing
with the etchant L are produced at the peripheral edge of the wafer
W. The wettability of the thin film F with the etchant L differs
from the wettability of the wafer W with the etchant L. For
example, even if the thin film F has a suitable wettability with
the etchant L, the exposed wafer W may, in some cases, have water
repellency to the etchant L. When the thin film F is removed by
etching, therefore, a width along which the etchant L flows around
to the upper surface of the wafer W may, in some cases, be
reduced.
[0011] In a region where the width along which the etchant L flows
around to the upper surface of the wafer W is reduced (hereinafter
referred to as "retreat region") B, an etching residue R is
produced. Further, a crystallized product S obtained by
crystallizing a component of the etchant L may, in some cases, be
produced in the retreat region B (see FIG. 11 (b)). The etching
residue R and the crystallized product S may cause particle
contamination and metal contamination, to contaminate another
apparatus or cause a device obtained from the wafer W to develop a
fault.
[0012] The second problem is that it is difficult to completely
remove such contaminants produced in the retreat region B of the
wafer W. When an attempt to remove the etching residue R and the
crystallized product S by cleaning processing, a cleaning liquid
must be efficiently supplied to the retreat region B.
[0013] Particularly when the surface of the wafer W is a
hydrophobic (water-repellent) surface, however, the retreat region
B (the exposed wafer W) may, in many cases, have a low wettability
with not only the etchant L but also the cleaning liquid such as
the deionized water D. Even if the cleaning liquid is supplied from
the reverse surface of the wafer W, therefore, the cleaning liquid
does not flow around to all portions of the retreat region B.
[0014] It is possible to adjust an amount in which the cleaning
liquid flows around to the upper surface of the wafer W by changing
conditions such as the number of revolutions of the wafer W. Even
by such a method, however, it is difficult to completely remove the
etching residue R and the crystallized product S. In order to
completely remove the etching residue R and the crystallized
product S, a long time period is required to clean the wafer W.
[0015] When an attempt to efficiently supply the cleaning liquid to
the retreat region B is made, because the step of removing the
etching residue R and the crystallized product S must be carried
out using an apparatus other than an apparatus for performing
etching processing, the whole step is complicated.
[0016] The third problem is that the cross-sectional shape of a
peripheral edge of the thin film F is rounded. Even if the supply
of the etchant L to the wafer W is stopped upon completion of the
etching processing, a part of the etchant L remains at the
peripheral edge of the wafer W, an end of the thin film F, and so
on. In this state, when the deionized water D is supplied to the
lower surface of the wafer W by adjusting the conditions such that
an amount in which the deionized water D flows around to the upper
surface of the wafer W is increased, the deionized water D flows
around to the upper surface of the wafer W while dissolving the
etchant L at the peripheral edge of the wafer W.
[0017] Therefore, a front end (a portion in contact with the thin
film F, which is indicated by hatching in FIG. 11 (c)) J of the
deionized water D flowing around to the upper surface of the wafer
W contains the etchant L at a high concentration. Therefore, the
peripheral edge of the thin film F is etched, so that the
cross-sectional shape of the peripheral edge of the thin film F is
rounded.
[0018] The fourth problem is that the contaminants such as the
particles P adhering to the surface of the thin film F cannot be
removed. In the above-mentioned method, the deionized water
(cleaning liquid) is not supplied to a large part, on the upper
surface of the thin film F, of the wafer W. Accordingly, the
particles P on the thin film F remain without being removed. In
order to remove the particles P, the wafer W must be cleaned by
another apparatus before or after the bevel etching is carried
out.
SUMMARY OF THE INVENTION
[0019] A first object of the present invention is to provide a
substrate processing method in which contaminants on a substrate
can be simply removed before or after processing of a peripheral
edge of the substrate.
[0020] A second object of the present invention is to provide a
substrate processing method in which peripheral edge processing for
supplying a processing liquid from one surface of a substrate to
process a peripheral edge of the substrate and cleaning of the
other surface of the substrate using a cleaning liquid can be
simply performed.
[0021] A third object of the present invention is to provide a
substrate processing apparatus capable of simply removing
contaminants on a substrate before or after processing of a
peripheral edge of the substrate.
[0022] A fourth object of the present invention is to provide a
substrate processing apparatus capable of simply performing
peripheral edge processing for supplying a processing liquid from
one surface of a substrate to process a peripheral edge of the
substrate and processing of the other surface of the substrate
using the processing liquid.
[0023] A substrate processing method according to the present
invention comprises a substrate rotating step for rotating a
substrate (W) with the substrate held almost horizontally within a
chamber (21); a peripheral edge processing step for discharging a
processing liquid (L) to a lower surface of the substrate rotated
in the substrate rotating step and causing the processing liquid to
flow around to an upper surface of the substrate at a peripheral
edge thereof from the lower surface of the substrate to process the
substrate in the chamber; and a both-surface processing step for
discharging a processing liquid (D, D0, D1) to both the surfaces of
the substrate rotated in the substrate rotating step to process
both the surfaces of the substrate in the chamber.
[0024] Although alphanumeric characters in parentheses indicate
corresponding constituent elements and the like in embodiments,
described later, it is not intended that the present invention
should be interpreted by being limited to the embodiments (the same
is true in the following).
[0025] According to the present invention, peripheral edge
processing for supplying the processing liquid to the lower surface
of the substrate to process the peripheral edge of the substrate
and both-surface processing for supplying the processing liquid to
both the surfaces of the substrate to process both the surfaces of
the substrate can be performed within the same chamber, that is, by
one apparatus. Consequently, the two types of processing can be
performed simply and in a short time period.
[0026] The processing liquid used in the peripheral edge processing
step may be a chemical such as an etchant, for example. When the
etchant is used as the processing liquid, so-called bevel etching
for etching a peripheral edge of the other surface of the substrate
can be carried out. The processing liquid used in the both-surface
processing step may be a cleaning liquid, for example. In this
case, the substrate can be cleaned. The substrate may be a circular
substrate such as a semiconductor wafer.
[0027] The both-surface processing step may comprise a
post-cleaning step for discharging a cleaning liquid (D, D0, D1) to
both the surfaces of the substrate rotated in the substrate
rotating step to clean the substrate after the peripheral edge
processing step.
[0028] According to this configuration, the cleaning liquid is
supplied to both the surfaces of the substrate. Accordingly,
contaminants (when the processing liquid is the etchant, for
example, an etching residue or a crystallized product obtained by
crystallizing a component of the etchant) produced as the
peripheral edge processing is performed are removed in a short time
period by the cleaning liquid even when they exist in any part of
the substrate.
[0029] In a case where the peripheral edge processing step is a
bevel etching step, for example, when the supply of the etchant is
stopped, a part of the etchant remains at the peripheral edge of
the substrate, the end of the thin film formed on the surface of
the substrate, or the like. The etchant is instantaneously removed
by the cleaning liquid supplied to both surfaces of the substrate
in the post-cleaning step subsequently carried out. Consequently,
the cleaning liquid containing the etchant at a high concentration
is not brought into contact with the thin film for a long time,
thereby making it possible to prevent a cross-sectional shape at an
end of a portion, which is not etched, of the thin film from being
rounded.
[0030] Furthermore, in the post-cleaning step, the other surface of
the substrate is cleaned by the cleaning liquid. Even when
contaminants such as particles adhere on the other surface of the
substrate (on the thin film formed on the other surface of the
substrate, for example), therefore, the contaminants can be
removed. Cleaning for removing the contaminants such as the
particles and cleaning for removing the contaminants caused by the
peripheral edge processing and the chemical itself may be separate
steps. In this case, a cleaning liquid for removing the
contaminants such as the particles (a particle removing liquid) and
a cleaning liquid for removing the contaminants caused by the
peripheral edge processing and the chemical itself may differ in
type.
[0031] The post-cleaning step may comprise a preliminary cleaning
step for discharging a preliminary cleaning liquid (D1) to the
substrate to clean the substrate, and a deionized water cleaning
step for discharging deionized water (D) to the substrate to clean
the substrate after the preliminary cleaning step.
[0032] According to this configuration, the preliminary cleaning
liquid used in the preliminary cleaning step can be removed in the
deionized water cleaning step after the contaminants caused by the
peripheral edge processing are removed by the preliminary cleaning
liquid in the preliminary cleaning step.
[0033] The preliminary cleaning liquid can be a chemical having a
low concentration (e.g., one of the same type as the chemical used
in the peripheral edge processing step), for example. Consequently,
the contaminants caused by the peripheral edge processing can be
quickly removed.
[0034] The both-surface processing step may comprise a pre-cleaning
step for discharging a cleaning liquid (D0) to both the surfaces of
the substrate rotated in the substrate rotating step to clean the
substrate before the peripheral edge processing step.
[0035] The other surface of the substrate may be cleaned in not the
post-cleaning step but the pre-cleaning step.
[0036] The substrate (W) processed in the peripheral edge
processing step and the both-surface processing step may include a
substrate (W) having a metal thin film (Fm) formed on its one
surface and its end surface.
[0037] In this case, the substrate is held and rotated with a
surface on which the metal thin film is formed directed upward in
the substrate rotating step, and a suitable etchant is discharged
onto the lower surface of the substrate in the peripheral edge
processing step, thereby making it possible to remove the metal
thin film on the end surface (peripheral surface) of the substrate
and at the peripheral edge of the upper surface thereof.
[0038] A substrate processing apparatus (10, 30, 40, 50, 60)
according to the present invention comprises a chamber (21); a
substrate rotating mechanism (1, 5) disposed in the chamber for
rotating a substrate (W) with the substrate held almost
horizontally; a lower surface processing liquid discharge nozzle
(8, 61, 62, 63) disposed in the chamber for discharging a
processing liquid (L, D, D0, D1) toward a lower surface of the
substrate rotated by the substrate rotating mechanism; an upper
surface processing liquid discharge nozzle (18, 34, 41, 42, 43, 51,
52, 53) disposed in the chamber for discharging a processing liquid
(D, D0, D1) toward an upper surface of the substrate rotated by the
substrate rotating mechanism; and a discharge control section (20)
for selectively switching, when the substrate is rotated by the
substrate rotating mechanism, a peripheral edge processed state
where the processing liquid (L) is discharged from the lower
surface processing liquid discharge nozzle to process a peripheral
edge of the substrate and a both-surface processed state where the
processing liquids (D, D0, D1) are simultaneously discharged from
the lower surface processing liquid discharge nozzle and the upper
surface processing liquid discharge nozzle to process both the
surfaces of the substrate, to control the discharge.
[0039] The substrate rotating mechanism (1) may comprise a spin
base (58a) arranged almost horizontally in a disk shape, and a
plurality of chuck pins (3) provided in a standing condition at a
peripheral edge of an upper surface of the spin base for holding
the substrate.
[0040] The lower surface processing liquid discharge nozzle may
include a nozzle (8, 61, 62, 63) for discharging the processing
liquid toward the center of the lower surface of the substrate held
in the substrate rotating mechanism. Further, the upper surface
processing liquid discharge nozzle may include a nozzle (18, 41,
42, 43, 51, 52, 53) for discharging the processing liquid toward
the center of the upper surface of the substrate held in the
substrate rotating mechanism.
[0041] When the substrate is rotated by the substrate rotating
mechanism, the processing liquid supplied to the center of the
lower surface of the substrate or the center of the upper surface
thereof expands toward the peripheral edge of the lower surface of
the substrate or the peripheral edge of the upper surface of the
substrate by a centrifugal force, thereby making it possible to
process the whole of the lower surface or the upper surface of the
substrate by the processing liquid.
[0042] There may be provided a plurality of lower processing liquid
discharge nozzles and/or a plurality of upper processing liquid
discharge nozzles. When the plurality of upper surface (lower
surface) processing liquid discharge nozzles are provided, the same
type of processing liquid may be simultaneously dischargeable from
the upper surface (lower surface) processing liquid discharge
nozzles. In this case, the upper surface (lower surface) processing
liquid discharge nozzles may be respectively directed toward
different regions with respect to the radial direction of the
substrate held in the substrate rotating mechanism. In this case,
it can be assumed that at least one of the upper surface (lower
surface) processing liquid discharge nozzles is directed toward the
vicinity of the center of the substrate held in the substrate
rotating mechanism.
[0043] The upper surface processing liquid discharge nozzle may
further include an auxiliary nozzle (34) for discharging the
processing liquid toward the peripheral edge of the upper surface
of the substrate held in the substrate rotating mechanism in
addition to the nozzle for discharging the processing liquid toward
the center of the upper surface of the substrate held in the
substrate rotating mechanism.
[0044] The auxiliary nozzle can be opposable to the vicinity of the
region to which the processing liquid discharged from the lower
surface processing liquid discharge nozzle flows around in the
vicinity of the peripheral edge of the upper surface of the
substrate. In this case, the contaminants produced as the
peripheral edge processing is performed can be removed quickly and
reliably.
[0045] Furthermore, the plurality of upper surface (lower surface)
processing liquid discharge nozzles may be provided, and different
types of processing liquids may be respectively dischargeable for
the upper surface (lower surface) processing liquid discharge
nozzles. In this case, it can be assumed that the upper surface
(lower surface) processing liquid discharge nozzles are
respectively connected to processing liquid supply sources
containing different types of processing liquids, and the
processing liquids contained in the processing liquid supply
sources are respectively supplied to the upper surface (lower
surface) processing liquid discharge nozzles along dedicated flow
paths. That is, the upper surface (lower surface) processing liquid
discharge nozzles can be configured such that there exist no flow
paths used in common by the different types of processing liquids.
In this case, each of the upper surface (lower surface) processing
liquid discharge nozzles shall be directed toward the vicinity of
the center of the substrate held in the substrate rotating
mechanism.
[0046] When there are two lower surface processing liquid discharge
nozzles, one of the lower surface processing liquid discharge
nozzles may be one capable of discharging a chemical, and the other
lower surface processing liquid discharge nozzle may be one capable
of discharging a cleaning liquid, for example.
[0047] The foregoing and other objects, features, aspects and
advantages of the present invention will become more apparent from
the following detailed description of the present invention when
taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0048] FIG. 1 (a) is a schematic cross-sectional view showing the
configuration of a substrate processing apparatus according to a
first embodiment of the present invention, which illustrates a
state where a shielding plate is at a distant position;
[0049] FIG. 1 (b) is a schematic cross-sectional view showing the
configuration of the substrate processing apparatus according to
the first embodiment of the present invention, which illustrates a
state where the shielding plate is at a proximal position;
[0050] FIG. 2 (a) is a schematic cross-sectional view for
explaining a wafer processing method according to a first
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0051] FIG. 2 (b) is a schematic cross-sectional view for
explaining the wafer processing method according to the first
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0052] FIG. 2 (c) is a schematic cross-sectional view for
explaining the wafer processing method according to the first
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0053] FIG. 3 (a) is a schematic cross-sectional view for
explaining a wafer processing method according to a second
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0054] FIG. 3 (b) is a schematic cross-sectional view for
explaining the wafer processing method according to the second
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0055] FIG. 3 (c) is a schematic cross-sectional view for
explaining the wafer processing method according to the second
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0056] FIG. 4 (a) is a schematic cross-sectional view for
explaining a wafer processing method according to a third
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0057] FIG. 4 (b) is a schematic cross-sectional view for
explaining the wafer processing method according to the third
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0058] FIG. 4 (c) is a schematic cross-sectional view for
explaining the wafer processing method according to the third
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0059] FIG. 5 (a) is a schematic cross-sectional view for
explaining a wafer processing method according to a fourth
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0060] FIG. 5 (b) is a schematic cross-sectional view for
explaining the wafer processing method according to the fourth
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0061] FIG. 5 (c) is a schematic cross-sectional view for
explaining the wafer processing method according to the fourth
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b);
[0062] FIG. 6 is a schematic cross-sectional view showing the
configuration of a substrate processing apparatus according to a
second embodiment of the present invention;
[0063] FIG. 7 (a) is a schematic cross-sectional view for
explaining an embodiment of a wafer processing method using the
substrate processing apparatus shown in FIG. 6;
[0064] FIG. 7 (b) is a schematic cross-sectional view for
explaining the embodiment of the wafer processing method using the
substrate processing apparatus shown in FIG. 6;
[0065] FIG. 7 (c) is a schematic cross-sectional view for
explaining the embodiment of the wafer processing method using the
substrate processing apparatus shown in FIG. 6;
[0066] FIG. 8 is a schematic cross-sectional view showing the
configuration of a substrate processing apparatus according to a
third embodiment of the present invention;
[0067] FIG. 9 is a schematic cross-sectional view showing the
configuration of a substrate processing apparatus according to a
fourth embodiment of the present invention;
[0068] FIG. 10 is a schematic cross-sectional view showing the
configuration of a substrate processing apparatus according to a
fifth embodiment of the present invention;
[0069] FIG. 11 (a) is a schematic cross-sectional view for
explaining a conventional method of bevel etching;
[0070] FIG. 11 (b) is a schematic cross-sectional view for
explaining the conventional method of bevel etching; and
[0071] FIG. 11 (c) is a schematic cross-sectional view for
explaining the conventional method of bevel etching.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0072] FIGS. 1 (a) and 1 (b) are schematic cross-sectional views
showing the configuration of a substrate processing apparatus 10
according to an embodiment of the present invention.
[0073] The substrate processing apparatus 10 comprises a chamber
21, a spin chuck 1 disposed in the chamber 21 comprising a
disk-shaped spin base rotated with a semiconductor wafer
(hereinafter merely referred to as a "wafer") W, which is an
example of a substrate, held almost horizontally, and a shielding
plate 2 disposed in the chamber 1 and disposed above the spin chuck
1. A plurality of chuck pins 3 are provided in a standing condition
at a peripheral edge of an upper surface of the spin base in the
spin chuck 1. The chuck pin 3 has a supporting section 3a for
supporting a peripheral edge of a lower surface of the wafer W and
a holding section 3b for holding an end surface (peripheral
surface) of the wafer W. The wafer W can be held by supporting
section 3a in the spin chuck 1 with the lower surface of the wafer
W opened.
[0074] The spin chuck 1 has a rotating shaft 4 disposed along a
vertical direction, and a rotation driving force is applied to the
rotating shaft 4 from a rotation driving mechanism 5. The wafer W
held in the spin chuck 1 can be rotated by the rotation driving
mechanism 5. A protecting member 9 is disposed around the rotating
shaft 4 so that the rotating shaft 4 and the rotation driving
mechanism 5 can be protected from a chemical or the like.
[0075] The rotating shaft 4 is in a tubular shape, and a lower
processing liquid pipe 6 is inserted into the rotating shaft 4. A
processing liquid supply path 7 is provided inside the lower
processing liquid pipe 6. An upper part of the processing liquid
supply path 7 is a lower nozzle 8 opened in the vicinity of the
center of an upper surface of the spin chuck 1.
[0076] A lower end of the lower processing liquid pipe 6 is
branched into a chemical pipe 11, a cleaning liquid pipe 12, and a
deionized water pipe 13. The chemical pipe 11 is connected to a
chemical supply source containing a chemical, the cleaning liquid
pipe 12 is connected to a cleaning liquid supply source containing
a cleaning liquid, and the deionized water pipe 13 is connected to
a deionized water supply source containing deionized water. A valve
11A is interposed in the chemical pipe 11, a valve 12A is
interposed in the cleaning liquid pipe 12, and a valve 13A is
interposed in the deionized water pipe 13. The chemical, the
cleaning liquid, and the deionized water can be switched,
introduced into the processing liquid supply path 7, and discharged
from the lower nozzle 8 by opening or closing the valves 11A, 12A,
and 13A.
[0077] The shielding plate 2 is a disk-shaped member having
approximately the same diameter as that of the spin chuck 1, and is
arranged almost horizontally. The shielding plate 2 has a rotating
shaft 14 arranged along a vertical direction, and a rotation
driving force is applied to the rotating shaft 14 from a rotation
driving mechanism 15. The shielding plate 2 can be rotated in the
same rotation direction and at the same revolutions as those of the
spin chuck 1 rotated by the rotation driving mechanism 5.
[0078] The rotating shaft 14 is in a tubular shape, and an upper
processing liquid pipe 16 is inserted into the rotating shaft 14. A
processing liquid supply path 17 is provided inside the upper
processing liquid pipe 16. A lower part of the processing liquid
supply path 17 is an upper nozzle 18 opened in the vicinity of the
center of a lower surface of the shielding plate 2.
[0079] An upper end of the upper processing liquid pipe 16 is
branched into a cleaning liquid pipe 22 and a deionized water pipe
23. The cleaning liquid pipe 22 is connected to a cleaning liquid
supply source containing a cleaning liquid, and the deionized water
pipe 23 is connected to a deionized water supply source containing
deionized water. A valve 22A is interposed in the cleaning liquid
pipe 22, and a valve 23A is interposed in the deionized water pipe
23. The cleaning liquid and the deionized water can be switched,
introduced into the processing liquid supply path 17, and
discharged from the upper nozzle 18 by opening or closing the
valves 22A and 23A.
[0080] The cleaning liquid supply source connected to the cleaning
liquid pipe 12 and the cleaning liquid supply source connected to
the cleaning liquid pipe 22 can be the same when the cleaning
liquids respectively contained therein are the same. The deionized
water supply source connected to the deionized water pipe 13 and
the deionized water supply source connected to the deionized water
pipe 23 may be the same.
[0081] A space between the upper processing liquid pipe 16 and an
inner wall of the rotating shaft 14 is a nitrogen gas supply path
26, and a lower end of the nitrogen gas supply path 26 is a
nitrogen gas discharge port 27 opened in the vicinity of the center
of a lower surface of the shielding plate 2. A nitrogen gas pipe 28
connected to a nitrogen gas supply source is communicated to the
nitrogen gas supply path 26 in an upper part of the rotating shaft
14. A valve 28A is interposed in the nitrogen gas pipe 28. It is
possible to introduce nitrogen gas into the nitrogen gas supply
path 26 by opening the valve 28A and to discharge the nitrogen gas
from the nitrogen gas discharge port 27.
[0082] The shielding plate 2 is raised or lowered by an up-and-down
mechanism 25, and can be moved between a distant position (see FIG.
1 (a)) where it is distant from the wafer W held in the spin chuck
1 and a proximal position (see FIG. 1 (b)) where it is in close
proximity to the wafer W held in the spin chuck 1.
[0083] The opening or closing of the valves 11A to 13A, 22A, 23A,
and 28A, the operations of the rotation driving mechanisms 5 and
15, and the operation of the up-and-down mechanism 25 are
controlled by a control section 20.
[0084] By the above-mentioned configuration, the substrate
processing apparatus 10 can perform peripheral edge processing for
supplying the chemical from the lower surface of the wafer W
rotated with the wafer W held in the spin chuck 1 to process the
peripheral edge of the wafer W and cleaning of the upper surface
and the lower surface of the wafer W by the cleaning liquid or the
deionized water within the same chamber 21, that is, by one
apparatus. Consequently, the two types of processing can be simply
performed.
[0085] FIGS. 2 (a) to 2 (c) are schematic cross-sectional views for
explaining a wafer processing method according to a first
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b). In the wafer processing method, it is possible to
remove, in a wafer having a thin film formed on both its surfaces,
the thin film on the one surface of the wafer and at a peripheral
edge of the other surface thereof by bevel etching.
[0086] A thin film Fs composed of silicon oxide (SiO.sub.2) or
silicon nitride (SiN) is formed on both surfaces and an end surface
(peripheral surface) of a wafer W. The chemical supply source
contains a hydrofluoric acid solution having a high concentration
as an etchant, and both the cleaning liquid supply sources
respectively connected to the cleaning liquid pipes 12 and 22
contain a hydrofluoric acid solution having a low concentration as
a preliminary cleaning liquid.
[0087] First, all the valves 11A to 13A, 22A, 23A, and 28A are
brought into a closed state under control of the control section
20, and the up-and-down mechanism 25 is controlled by the control
section 20 so that the shielding plate 2 is moved to the distant
position. The wafer W is delivered to the spin chuck 1 by a robot
hand (not shown), and is held almost horizontally on the spin chuck
1. By the control section 20, the up-and-down mechanism 25 is
controlled so that the shielding plate 2 is moved to the proximal
position, and the rotation driving mechanisms 5 and 15 are
controlled so that the wafer W held in the spin chuck 1 and the
shielding plate 2 are rotated around a central axis C of the wafer
W.
[0088] Subsequently, the valve 28A is opened under control of the
control section 20, so that nitrogen gas is discharged from the
nitrogen gas discharge port 27. Accordingly, oxygen partial
pressure in a space between the spin chuck 1 and the shielding
plate 2 is reduced.
[0089] In this state, the valve 11A is opened under control of the
control section 20, so that an etchant L is discharged toward the
vicinity of the center of the lower surface of the wafer W from the
lower nozzle 8. The etchant L expands along the lower surface of
the wafer W by a centrifugal force caused by the rotation of the
wafer W, to be spun off sideward at the peripheral edge of the
wafer W. The surface of the thin film Fs has a wettability with the
etchant L. Accordingly, a part of the etchant L flows around to the
upper surface of the wafer W at the peripheral edge thereof (see
FIG. 2 (a)). Consequently, the thin film Fs on the lower surface
and the end surface (peripheral surface) of the wafer W and at the
peripheral edge of the upper surface thereof is etched away.
[0090] The wettability of a portion, which is exposed because the
thin film Fs is removed, of the wafer W with the etchant L is lower
than the wettability of the thin film Fs with the etchant L. When
the thin film Fs at the peripheral edge of the upper surface of the
wafer W is removed, therefore, a width along which the etchant L
flows around to the upper surface of the wafer W is reduced. In a
region (hereinafter referred to as a "retreat region") B where the
width along which the etchant L flows around to the upper surface
of the wafer W is reduced, an etching residue R is produced (see
FIG. 2 (b)).
[0091] The valves 11A and 28A are then closed under control of the
control section 20, so that the supply of the etchant L and the
nitrogen gas is stopped. In this state, the etchant L remains at
the peripheral edge of the wafer W and in the vicinity of an end of
the thin film Fs. Thereafter, by the control section 20, the
up-and-down mechanism 25 is controlled so that the shielding plate
2 is moved to the distant position, and the rotation driving
mechanism 15 is controlled so that the rotation of the shielding
plate 2 is stopped.
[0092] Subsequently, the valves 12A and 22A are opened under
control of the control section 20, so that a preliminary cleaning
liquid D1 is discharged toward the lower surface and the upper
surface of the wafer W, respectively, from the lower nozzle 8 and
the upper nozzle 18. The preliminary cleaning liquid D1 expands
along the lower surface and the upper surface of the wafer W, to be
spun off sideward at the peripheral edge of the wafer W. In this
case, by the preliminary cleaning liquid D1, the etchant L
remaining at the peripheral edge of the wafer W and in the vicinity
of the end of the thin film Fs is instantaneously removed, and the
etching residue R produced in the retreat region B is easily
removed (see FIG. 2 (c)).
[0093] Then, under control of the control section 20, the valves
12A and 22A are closed, and the valves 13A and 23A are opened, so
that deionized water is discharged toward the lower surface and the
upper surface of the wafer W, respectively, from the lower nozzle 8
and the upper nozzle 18. Consequently, the preliminary cleaning
liquid D1 on the wafer W is removed. After the deionized water is
discharged for a predetermined time period, the valves 13A and 23A
are closed under control of the control section 20.
[0094] Thereafter, the rotation driving mechanism 5 is controlled
by the control section 20, so that the wafer W held in the spin
chuck 1 is rotated at high speed, to be spun off and dried. The
processing of one wafer W is thus terminated.
[0095] In the foregoing method of processing the wafer W, the
etching residue R produced as the etching processing is performed
is simply removed by the preliminary cleaning liquid D1. Therefore,
the wafer W can be cleaned in a short time period after the etching
processing.
[0096] After the supply of the etchant L is stopped, the etchant L
remaining on the wafer W is instantaneously removed by the
preliminary cleaning liquid D1 supplied to the lower surface and
the upper surface of the wafer W. Consequently, a hydrofluoric acid
solution having a high concentration is not brought into contact
with the thin film Fs for a long time. Accordingly, the thin film
Fs formed on the surface of the wafer W can be etched such that the
cross-sectional shape of an end K1 after the etching is not
rounded.
[0097] FIGS. 3 (a) to 3 (c) are schematic cross-sectional views for
explaining a wafer processing method according to a second
embodiment using the substrate processing apparatus shown in FIGS.
1 (a) and 1 (b). In the wafer processing method, it is possible to
remove particles adhering to a surface of a thin film formed on one
surface of a wafer and subject the thin film to bevel etching.
[0098] A metal thin film Fm composed of copper (Cu) or the like is
formed on one surface and an end surface (peripheral surface) of a
wafer W. Particles P produced at the time of forming the metal thin
film Fm adhere to a surface of the metal thin film Fm. The chemical
supply source contains an etchant composed of a solution containing
one or more components selected form hydrochloric acid,
hydrofluoric acid, nitric acid, and hydrogen peroxide, and both the
cleaning liquid supply sources respectively connected to the
cleaning liquid pipes 12 and 22 contain a mixed solution of aqueous
ammonia, hydrofluoric acid, and water (hereinafter referred to as a
"particle removing liquid").
[0099] First, all the valves 11A to 13A, 22A, 23A, and 28A are
brought into a closed state under control of the control section
20, and the up-and-down mechanism 25 is controlled by the control
section 20 so that the shielding plate 2 is moved to the distant
position. The wafer W is delivered to the spin chuck 1 by a robot
hand (not shown), and is held almost horizontally on the spin chuck
1 with its surface on which the metal film Fm is formed directed
upward. The up-and-down mechanism 5 is controlled by the control
section 20 so that the wafer W held in the spin chuck 1 is rotated
around its central axis C.
[0100] In this state, the valves 12A and 22A are opened under
control of the control section 20, so that a particle removing
liquid D0 is discharged toward the vicinities of the centers of the
lower surface and the upper surface of the wafer W, respectively,
from the lower nozzle 8 and the upper nozzle 18, thereby carrying
out a pre-cleaning step. The particle removing liquid D0 expands
along the upper surface and the lower surface of the wafer W by a
centrifugal force caused by the rotation of the wafer W, to be spun
off sideward at the peripheral edge of the wafer W (see FIG. 3 (a))
. In this case, the particles P adhering to the surface of the
metal thin film Fm are removed. After the particle removing liquid
D0 is discharged for a predetermined time period, the valves 12A
and 22A are closed under control of the control section 20 so that
the supply of the particle removing liquid D0 is stopped, thereby
terminating the pre-cleaning step.
[0101] Subsequently, the rotation driving mechanism 15 is
controlled by the control section 20, so that the shielding plate 2
is rotated. The up-and-down mechanism 25 is controlled by the
control section 20, so that the shielding plate 2 is moved to the
proximal position. The valve 28A is opened under control of the
control section 20, so that nitrogen gas is discharged from the
nitrogen gas discharge port 27. Accordingly, oxygen partial
pressure in a space between the spin chuck 1 and the shielding
plate 2 is reduced.
[0102] In this state, the valve 11A is opened under control of the
control section 20, so that an etchant L is discharged toward the
vicinity of the center of the lower surface of the wafer W from the
lower nozzle 8. The etchant L expands along the lower surface of
the wafer W by a centrifugal force caused by the rotation of the
wafer W, to be spun off sideward at the peripheral edge of the
wafer W. The respective surfaces of the wafer W and the metal thin
film Fm have a wettability with the etchant L. Accordingly, a part
of the etchant L flows around to the upper surface of the wafer W
at the peripheral edge thereof (see FIG. 3 (b)). Consequently, the
metal thin film Fm on the end surface (peripheral surface) of the
wafer W and at the peripheral edge of the upper surface thereof is
etched away (see FIG. 3 (c)). Therefore, the metal thin film Fm
from which the particles P are removed can be left in a device
formation region of the wafer W.
[0103] The valves 11A and 28A are then closed under control of the
control section 20, so that the supply of the etchant L and the
nitrogen gas is stopped. By the control section 20, the up-and-down
mechanism 25 is controlled so that the shielding plate 2 is moved
to the distant position, and the rotation driving mechanism 15 is
controlled so that the rotation of the shielding plate 2 is
stopped.
[0104] Subsequently, the valves 13A and 23A are opened under
control of the control section 20, so that deionized water is
discharged toward the lower surface and the upper surface of the
wafer W, respectively, from the lower nozzle 8 and the upper nozzle
18. Consequently, the etchant L on the wafer W is removed. After
the deionized water is supplied for a predetermined time period,
the valves 13A and 23A are closed under control of the control
section 20.
[0105] Thereafter, the rotation driving mechanism 5 is controlled
by the control section 20, so that the wafer W held in the spin
chuck 1 is rotated at high speed, to be spun off and dried. The
processing of one wafer W is thus terminated.
[0106] In the foregoing method of processing the wafer W, the
removal of the particles P adhering to the metal thin film Fm, the
etching of the metal thin film Fm, and the subsequent cleaning of
the wafer W using the deionized water can be simply carried out
continuously by one apparatus.
[0107] The second embodiment can be deformed, as follows. That is,
the substrate processing apparatus 10 shown in FIGS. 1 (a) and 1
(b) may be so configured that an etchant having a low concentration
is selected as a preliminary cleaning liquid to be dischargeable
from the lower nozzle 8 and the upper nozzle 18. In this case, when
the retreat region B appears after the metal thin film Fm is
removed so that the etching residue R is produced, preliminary
cleaning can be performed by supplying the preliminary cleaning
liquid to the upper surface and the lower surface of the wafer W
after etching using the etchant L and before cleaning using the
deionized water. Consequently, the etching residue R is easily
removed.
[0108] After the metal thin film Fm is first etched, the particles
P on the metal thin film Fm may be removed using a mixed solution
of aqueous ammonia, hydrogen peroxide, and water (a particle
removing liquid).
[0109] Furthermore, the metal thin film Fm may be composed of
tantalum (Ta) or titanium (Ti) in addition to copper. A thin film
of a nitride such as tantalum nitride (TaN) or titanium nitride
(TiN) or a thin film of an oxide such as tantalum oxide
(Ta.sub.2O.sub.5) may be formed on the surface of the wafer W in
place of the metal thin film Fm.
[0110] In this case, the particle removing liquid D0 may be a mixed
solution of hydrofluoric acid, hydrogen peroxide, and water, or a
hydrofluoric acid solution in addition to a mixed solution of
aqueous ammonia, hydrogen peroxide, and water. In this case, the
etchant L may be a mixed solution of hydrofluoric acid, nitric
acid, and water, a hydrofluoric acid solution, a mixed solution of
hydrofluoric acid, ozone water, and water, or a mixed solution of
hydrochloric acid, hydrogen peroxide, and water. As the respective
types of the particle removing liquid D0 and the etchant L,
suitable ones of the foregoing types can be respectively selected
depending on the types of the thin film formed on the surface of
the wafer W.
[0111] FIGS. 4 (a) to 4 (c) are schematic cross-sectional views for
explaining a wafer processing method according to a third
embodiment using the substrate processing apparatus 10 shown in
FIGS. 1 (a) and 1 (b). In the wafer processing method, a thin film
formed with an approximately uniform thickness on both surfaces of
a wafer can be subjected to bevel etching so that the thin film has
a thickness distribution.
[0112] A thin film Fs composed of silicon oxide (SiO.sub.2) or
silicon nitride (SiN) is formed with an approximately uniform
thickness on both surfaces and an end surface (peripheral surface)
of a wafer W. The chemical supply source contains a fluoric acid
solution having a high concentration as an etchant.
[0113] First, all the valves 11A to 13A, 22A, 23A, and 28A are
brought into a closed state under control of the control section
20, and the up-and-down mechanism 25 is controlled by the control
section 20 so that the shielding plate 2 is moved to the distant
position. The wafer W is delivered to the spin chuck 1 by a robot
hand (not shown), and is held almost horizontally on the spin chuck
1. The up-and-down mechanism 25 is then controlled by the control
section 20 so that the shielding plate 2 is moved to the proximal
position, and the rotation driving mechanisms 5 and 15 are
controlled so that the wafer W held in the spin chuck 1 and the
shielding plate 2 are rotated around a central axis C of the wafer
W.
[0114] Subsequently, the valve 28A is opened under control of the
control section 20, so that nitrogen gas is discharged from the
nitrogen gas discharge port 27. Accordingly, oxygen partial
pressure in a space between the spin chuck 1 and the shielding
plate 2 is reduced.
[0115] In this state, the valve 11A is opened under control of the
control section 20, so that an etchant L is discharged toward the
vicinity of the center of the lower surface of the wafer W from the
lower nozzle 8. The etchant L expands along the lower surface of
the wafer W by a centrifugal force caused by the rotation of the
wafer W, to be spun off sideward at the peripheral edge of the
wafer W. The surface of the thin film Fs has a wettability with the
etchant L. Accordingly, a part of the etchant L flows around to the
upper surface of the wafer W at the peripheral edge thereof (see
FIG. 4 (a)). Consequently, the thin film Fs on the lower surface
and the end surface (peripheral surface) of the wafer W and at the
peripheral edge of the upper surface thereof is etched to be
thinned.
[0116] When the thin film Fs on the lower surface of the wafer W
and at the peripheral edge thereof is thinned to a suitable
thickness, the valve 11A is closed under control of the control
section 20. Consequently, the supply of the etchant L to the wafer
W is stopped. Since the thin film Fs has a wettability with the
etchant L, the etchant L remains at the peripheral edge of the
wafer W (see FIG. 4). Further, the valve 28A is closed under
control of the control section 20, so that the supply of nitrogen
gas is stopped.
[0117] Subsequently, by the control section 20, the up-and-down
mechanism 25 is controlled so that the shielding plate 2 is moved
to the distant position, and the rotation driving mechanism 15 is
controlled so that the rotation of the shielding plate 2 is
stopped. The valves 13A and 23A are opened under control of the
control section 20, so that deionized water D is discharged toward
the lower surface and the upper surface of the wafer W,
respectively, from the lower nozzle 8 and the upper nozzle 18 (see
FIG. 4 (c)). Consequently, the etchant L remaining at the
peripheral edge of the wafer W is instantaneously removed. After
the deionized water D is discharged for a predetermined time
period, the valves 13A and 23A are closed under control of the
control section 20.
[0118] Thereafter, the rotation driving mechanism 5 is controlled
by the control section 20, so that the wafer W held in the spin
chuck 1 is rotated at high speed, to be spun off and dried. The
processing of one wafer W is thus terminated.
[0119] In the foregoing method of processing the wafer W, after the
supply of the etchant L is stopped, the etchant L remaining at the
peripheral edge of the wafer W is instantaneously removed by the
deionized water D supplied to lower surface and the upper surface
of the wafer W. Consequently, a fluoric acid solution having a high
concentration is not brought into contact with an end K2 of a
portion, which is not thinned, of the thin film Fs for a long time.
Accordingly, the cross-sectional shape at the end of the portion,
which is not thinned, of the thin film Fs can be prevented from
being rounded.
[0120] FIGS. 5 (a) to 5 (c) are schematic cross-sectional views for
explaining a wafer processing method according to a fourth
embodiment using the substrate processing apparatus 10 shown in
FIGS. 1 (a) and 1 (b). In the wafer processing method, it is
possible to remove, in a wafer having a thin film formed on both
its surfaces, the thin film on the one surface of the wafer and at
a peripheral edge of the other surface thereof by bevel
etching.
[0121] A thin film Fs composed of silicon oxide (SiO.sub.2) or
silicon nitride (SiN) is formed on both surfaces and an end surface
(peripheral surface) of a wafer W. The chemical supply source
contains a buffered hydrofluoric acid solution (a mixed solution of
fluoric acid, ammonium fluoride, and water) as an etchant, and both
the cleaning liquid supply sources respectively connected to the
cleaning liquid pipes 12 and 22 contain a fluoric acid solution
having a low concentration as a preliminary cleaning liquid.
[0122] First, all the valves 11A to 13A, 22A, 23A, and 28A are
brought into a closed state under control of the control section
20, and the up-and-down mechanism 25 is controlled by the control
section 20 so that the shielding plate 2 is moved to the distant
position. The wafer W is delivered to the spin chuck 1 by a robot
hand (not shown), and is held almost horizontally on the spin chuck
1. By the control section 20, the up-and-down mechanism 25 is
controlled so that the shielding plate 2 is moved to the proximal
position, and the rotation driving mechanisms 5 and 15 are
controlled so that the wafer W held in the spin chuck 1 and the
shielding plate 2 are rotated around a central axis C of the wafer
W.
[0123] Subsequently, the valve 28A is opened under control of the
control section 20, so that nitrogen gas is discharged from the
nitrogen gas discharge port 27. Accordingly, oxygen partial
pressure in a space between the spin chuck 1 and the shielding
plate 2 is reduced.
[0124] In this state, the valve 11A is opened under control of the
control section 20, so that an etchant L is discharged toward the
vicinity of the center of the lower surface of the wafer W from the
lower nozzle 8. The etchant L expands along the lower surface of
the wafer W by a centrifugal force caused by the rotation of the
wafer W, to be spun off sideward at the peripheral edge of the
wafer W. The surface of the thin film Fs has a wettability with the
etchant L. Accordingly, a part of the etchant L flows around to the
upper surface of the wafer W (see FIG. 5 (a)). Consequently, the
thin film Fs on the lower surface and the end surface (peripheral
surface) of the wafer W and at the peripheral edge of the upper
surface thereof is etched away.
[0125] The wettability of a portion, which is exposed because the
thin film Fs is removed, of the wafer W with the etchant L is lower
than the wettability of the thin film Fs with the etchant L. When
the thin film Fs at the peripheral edge of the upper surface of the
wafer W is removed, therefore, a width along which the etchant L
flows around to the upper surface of the wafer W is reduced, so
that a retreat region B appears. When water evaporates, a
constituent component of a buffered hydrofluoric acid solution is
crystallized. Therefore, a crystallized product S is produced in
the retreat region B (see FIG. 5 (b)).
[0126] The valves 11A and 28A are then closed under control of the
control section 20, so that the supply of the etchant L and the
nitrogen gas is stopped. By the control section 20, the up-and-down
mechanism 25 is controlled so that the shielding plate 2 is moved
to the distant position, and the rotation driving mechanism 15 is
controlled so that the rotation of the shielding plate 2 is
stopped.
[0127] Subsequently, the valves 12A and 22A are opened under
control of the control section 20, so that a preliminary cleaning
liquid D1 is discharged toward the lower surface and the upper
surface of the wafer W, respectively, from the lower nozzle 8 and
the upper nozzle 18. The preliminary cleaning liquid D1 expands
along the lower surface and the upper surface of the wafer W, to be
spun off sideward at the peripheral edge of the wafer W. In this
case, the crystallized product S produced in the retreat region B
is easily removed by the preliminary cleaning liquid D1 (see FIG. 5
(c)).
[0128] Then, under control of the control section 20, the valves
12A and 22A are closed, and the valves 13A and 23A are opened, so
that deionized water is discharged toward the lower surface and the
upper surface of the wafer W, respectively, from the lower nozzle 8
and the upper nozzle 18, thereby cleaning the wafer W.
Consequently, the preliminary cleaning liquid D1 on the wafer W is
removed. After the deionized water is discharged for a
predetermined time period, the valves 13A and 23A are closed under
control of the control section 20.
[0129] Thereafter, the rotation driving mechanism 5 is controlled
by the control section 20, so that the wafer W held in the spin
chuck 1 is rotated at high speed, to be spun off and dried. The
processing of one wafer W is thus terminated.
[0130] In the foregoing method of processing the wafer W, the
crystallized product S produced as the etching processing is
performed is simply removed by the preliminary cleaning liquid D1.
Therefore, the wafer W can be cleaned in a short time period after
the etching processing.
[0131] The fourth embodiment can be deformed, as follows. That is,
an etchant L (a chemical) is not limited to the buffered
hydrofluoric acid solution. When the etchant L is one which
produces a crystallized product S by the evaporation of a solvent,
the crystallized product S can be easily removed by the same
method. In this case, selected as the preliminary cleaning liquid
D1 is one more suitable for the type of the etchant L.
[0132] FIG. 6 is a schematic cross-sectional view showing the
configuration of a substrate processing apparatus 30 according to a
second embodiment of the present invention. In FIG. 6, constituent
elements corresponding to the constituent elements of the substrate
processing apparatus 10 shown in FIGS. 1 (a) and 1 (b) are assigned
the same reference alphanumeric characters and hence, the
description thereof is not repeated.
[0133] The substrate processing apparatus 30 comprises an auxiliary
processing mechanism 31 for supplying a processing liquid to a
peripheral edge of an upper surface of a wafer W held in a spin
chuck 1 in addition to the constituent elements of the substrate
processing apparatus 10 shown in FIGS. 1 (a) and 1 (b). The
auxiliary processing mechanism 31 comprises a processing liquid
pipe 32 disposed along a vertical direction beside the spin chuck
1, an extending pipe 33 extending along an approximately horizontal
direction from an upper end of the processing liquid pipe 32, and
an auxiliary nozzle 34 connected to a front end of the extending
pipe 33. The extending pipe 33 is disposed at a position higher
than the wafer W held in the spin chuck 1. The auxiliary nozzle 34
is directed downward and is opened at a height position
corresponding to a position just above the wafer W held in the spin
chuck 1.
[0134] A lower end of the processing liquid pipe 32 is branched
into a cleaning liquid pipe 35 and a deionized water pipe 36. The
cleaning liquid pipe 35 is connected to a cleaning liquid supply
source containing a cleaning liquid, and the deionized water pipe
36 is connected to a deionized water supply source containing
deionized water. A valve 35A is interposed in the cleaning liquid
pipe 35, and a valve 36A is interposed in the deionized water pipe
36. The cleaning liquid and the deionized water can be switched and
discharged from the auxiliary nozzle 34 by respectively opening or
closing the valves 35A and 36A. The opening or closing of the
valves 35A and 36A is controlled by a control section 20.
[0135] A rotating mechanism 37 is coupled to the cleaning liquid
pipe 35, and the cleaning liquid pipe 32 can be rotated around its
axis. Consequently, the auxiliary nozzle 34 can be moved between an
opposed position where it is opposed to a peripheral edge of an
upper surface of the wafer W held in the spin chuck 1 and a
stand-by position where it retreats from an upper part of the wafer
W.
[0136] By the above-mentioned configuration, the cleaning liquid
and the deionized water can be switched and discharged to the
peripheral edge of the wafer W held in the spin chuck 1 using the
auxiliary processing mechanism 31.
[0137] The cleaning liquid supply source connected to the cleaning
liquid pipe 35 may be the same as or different from the cleaning
liquid supply source connected to the cleaning liquid pipe 12 or
the cleaning liquid supply source connected to the cleaning liquid
pipe 22. Similarly, the deionized water supply source connected to
the deionized water pipe 36 may be the same as or different from
the deionized water supply source connected to the deionized water
pipe 13 or the deionized water supply source connected to the
deionized water pipe 23.
[0138] FIGS. 7 (a) to 7 (c) are schematic cross-sectional views for
explaining an embodiment of a wafer processing method using the
substrate processing apparatus 30 shown in FIG. 6. In FIGS. 7 (a)
to 7 (c), constituent elements and the like corresponding to the
constituent elements shown in FIGS. 2 (a) to 2 (c) and FIG. 6 are
assigned the same reference alphanumeric characters and hence, the
description thereof is not repeated. In the wafer processing
method, it is possible to remove, in a wafer having a thin film
formed on both its surfaces, the thin film on the one surface of
the wafer and at a peripheral edge of the other surface thereof by
bevel etching.
[0139] A thin film Fs composed of silicon oxide or silicon nitride
is formed on both surfaces and an end surface (peripheral surface)
of a wafer W. The chemical supply source contains a hydrofluoric
acid solution having a high concentration as an etchant, and the
cleaning liquid supply sources respectively connected to the
cleaning liquid pipes 12, 22 and 35 contain a hydrofluoric acid
solution having a low concentration as a preliminary cleaning
liquid.
[0140] First, all the valves 11A to 13A, 22A, 23A, 28A, 35A and 36A
are brought into a closed state under control of the control
section 20. By the control section 20, the up-and-down mechanism 25
is controlled so that the shielding plate 2 is moved to the distant
position, and the rotating mechanism 37 is controlled so that the
auxiliary nozzle 34 is moved to the stand-by position. In this
state, the wafer W is delivered to the spin chuck 1 by a robot hand
(not shown), and is held almost horizontally on the spin chuck
1.
[0141] By the control section 20, the up-and-down mechanism 25 is
then controlled so that the shielding plate 2 is moved to the
proximal position, and the rotation driving mechanisms 5 and 15 are
controlled so that the wafer W held in the spin chuck 1 and the
shielding plate 2 are rotated around a central axis C of the wafer
W. Subsequently, the valve 28A is opened under control of the
control section 20, so that nitrogen gas is discharged from the
nitrogen gas discharge port 27. Accordingly, oxygen partial
pressure in a space between the spin chuck 1 and the shielding
plate 2 is reduced.
[0142] In this state, the valve 11A is opened under control of the
control section 20, so that an etchant L is discharged toward the
vicinity of the center of the lower surface of the wafer W from the
lower nozzle 8 (see FIG. 7 (a)) . Consequently, the thin film Fs on
the lower surface and the end surface (peripheral surface) of the
wafer W and at the peripheral edge of the upper surface thereof is
etched away. Correspondingly, a retreat region B appears, so that
an etching residue R is produced in the retreat region B (see FIG.
7 (b)).
[0143] The valve 11A is then closed under control of the control
section 20, so that the supply of the etchant L is stopped. In this
state, the etchant L remains at the peripheral edge of the wafer W
and in the vicinity of an end of the thin film Fs. Thereafter, the
rotation driving mechanism 15 is controlled by the control section
20 so that the rotation of the shielding plate 2 is stopped.
[0144] The up-and-down mechanism 25 is then controlled by the
control section 20, so that the shielding plate 2 is slightly
raised from the proximal position, and is brought into a state
where the auxiliary nozzle 34 and the extending pipe 33 are
insertable between the wafer W held in the spin chuck 1 and the
shielding plate 2. Thereafter, the rotation driving mechanism 15 is
controlled by the control section 20, so that the shielding plate 2
is rotated again.
[0145] Subsequently, the rotating mechanism 37 is controlled by the
control section 20, so that the auxiliary nozzle 34 is moved to the
opposite position. Consequently, the auxiliary nozzle 34 is opposed
to the vicinity of the retreat region B. Further, the valves 12A,
22A, and 35A are opened under control of the control section 20, so
that a preliminary cleaning liquid D1 is discharged toward the
center of the lower surface of the wafer W, the center of the upper
surface of the wafer W, and the peripheral edge of the upper
surface of the wafer W, respectively, from the lower nozzle 8, the
upper nozzle 18, and the auxiliary nozzle 34. The discharge of the
nitrogen gas from the nitrogen gas discharge port 27 is
continued.
[0146] The preliminary cleaning liquid D1 discharged from the lower
nozzle 8 and the upper nozzle 18 expands along the lower surface
and the upper surface of the wafer W, to be spun off sideward at
the peripheral edge of the wafer W. The preliminary cleaning liquid
D1 is directly supplied to the vicinity of the retreat region B
from the auxiliary nozzle 34 (see FIG. 7 (c)). Consequently, the
etchant L and the etching residue R which remain at the peripheral
edge of the wafer W and in the vicinity of the end of the thin film
Fs are instantaneously removed.
[0147] After the preliminary cleaning liquid D1 is discharged for a
predetermined time period, the valves 12A, 22A, and 35A are closed
under control of the control section 20, so that the discharge of
the preliminary cleaning liquid D1 from the lower nozzle 8, the
upper nozzle 18, and the auxiliary nozzle 34 is terminated. The
valves 13A, 23A, and 36A are opened under control of the control
section 20, so that deionized water is discharged toward the center
of the lower surface of the wafer W, the center of the upper
surface of the wafer W, and the peripheral edge of the upper
surface of the wafer W, respectively, from the lower nozzle 8, the
upper nozzle 18, and the auxiliary nozzle 34. The discharge of the
nitrogen gas from the nitrogen gas discharge port 27 is
continued.
[0148] The deionized water discharged from the lower nozzle 8 and
the upper nozzle 18 expands along the lower surface and the upper
surface of the wafer W, to be spun off sideward at the peripheral
edge of the wafer W. The deionized water is directly supplied to
the vicinity of the retreat region B from the auxiliary nozzle 34.
Consequently, the preliminary cleaning liquid D1 on the wafer W is
instantaneously removed.
[0149] After the deionized water is discharged for a predetermined
time period, the valves 13A, 23A, and 36A are closed under control
of the control section 20. Subsequently, the rotation driving
mechanism 5 is controlled by the control section 20, so that the
wafer W held in the spin chuck 1 is rotated at high speed, to be
spun off and dried. Thereafter, the valve 28A is closed under
control of the control section 20, so that the discharge of the
nitrogen gas from the nitrogen gas discharge port 27 is terminated.
The processing of one wafer W is thus terminated.
[0150] In the foregoing method of processing the wafer W, the steps
from the bevel etching processing to the processing for spinning
off and drying the wafer W are all carried out under an atmosphere
of low oxygen partial pressure, whereby the wafer W can hardly be
oxidized. Further, the preliminary cleaning liquid D1 and the
deionized water are directly supplied to the vicinity of the
retreat region B from the auxiliary nozzle 34, whereby the etching
residue R, the etchant, and the preliminary cleaning liquid which
exist in the vicinity of the retreat region B are removed quickly
and reliably.
[0151] FIG. 8 is a schematic cross-sectional view showing the
configuration of a substrate processing apparatus 40 according to a
third embodiment of the present invention. In FIG. 8, constituent
elements corresponding to the constituent elements of the substrate
processing apparatus 10 shown in FIGS. 1 (a) and 1 (b) are assigned
the same reference alphanumeric characters and hence, the
description thereof is not repeated.
[0152] Although the substrate processing apparatus 40 has the same
configuration as that of the substrate processing apparatus shown
in FIGS. 1 (a) and 1 (b), the shielding plate 2 is not provided.
Further, a particle removing liquid discharge nozzle 41, a
preliminary cleaning liquid discharge nozzle 42, and a deionized
water discharge nozzle 43 are provided at positions shifted from a
central axis C of a wafer W held in a spin chuck 1 above the spin
chuck 1. The particle removing liquid discharge nozzle 41, the
preliminary cleaning liquid discharge nozzle 42, and the deionized
water discharge nozzle 43 are respectively arranged at different
height positions. The deionized water discharge nozzle 43 is at the
lowest position, and the particle removing liquid discharge nozzle
41 is at the highest position. All the particle removing liquid
discharge nozzle 41, the preliminary cleaning liquid discharge
nozzle 42, and the deionized water discharge nozzle 43 are directed
toward the center of the wafer W held in the spin chuck 1.
[0153] The particle removing liquid discharge nozzle 41 is
connected to a particle removing liquid supply source through a
particle removing liquid pipe 44. The preliminary cleaning liquid
discharge nozzle 42 is connected to a preliminary cleaning liquid
supply source through a preliminary cleaning liquid pipe 45. The
deionized water discharge nozzle 43 is connected to a deionized
water supply source through a deionized water pipe 46. A valve 44A
is interposed in the particle removing liquid pipe 44, a valve 45A
is interposed in the preliminary cleaning liquid pipe 45, and a
valve 46A is interposed in the deionized water pipe 46.
[0154] A particle removing liquid, a preliminary cleaning liquid,
and deionized water can be respectively discharged toward the
vicinity of the center of an upper surface of the wafer W held in
the spin chuck 1 from the particle removing liquid discharge nozzle
41, the preliminary cleaning liquid discharge nozzle 42, and the
deionized water discharge nozzle 43 by opening or closing the
valves 44A, 45A, and 46A.
[0155] Consequently, it is possible to remove particles by the
particle removing liquid, remove an etching residue R and an
etchant by the preliminary cleaning liquid, and remove the
preliminary cleaning liquid or the particle removing liquid by the
deionized water.
[0156] The substrate processing apparatus 40 does not have a flow
path employed in common by two or more types of processing liquids
out of the particle removing liquid, the preliminary cleaning
liquid, and the deionized water which are supplied to the upper
surface of the wafer W. Consequently, a liquid obtained by mixing
two or more types of processing liquids out of the particle
removing liquid, the preliminary cleaning liquid, and the deionized
water can be prevented from being supplied to the upper surface of
the wafer W.
[0157] FIG. 9 is a schematic cross-sectional view showing the
configuration of a substrate processing apparatus 50 according to a
fourth embodiment of the present invention. In FIG. 9, constituent
elements corresponding to the constituent elements of the substrate
processing apparatus 10 shown in FIGS. 1 (a) and 1 (b) are assigned
the same reference alphanumeric characters and hence, the
description thereof is not repeated.
[0158] Although the substrate processing apparatus 50 has the same
configuration as that of the substrate processing apparatus shown
in FIGS. 1 (a) and 1 (b), the shielding plate 2 is not provided,
similarly to the substrate processing apparatus 40 shown in FIG. 8.
Further, first to third upper nozzles 51 to 53 are provided above a
spin chuck 1 in place of the upper nozzle 18. The first upper
nozzle 51 is arranged nearly on a central axis C of a wafer W held
in the spin chuck 1, and the third upper nozzle 53 is arranged
above a peripheral edge of the wafer W. The second upper nozzle 52
is arranged between the first upper nozzle 51 and the third upper
nozzle 53 with respect to the radial direction of the wafer W. All
the first to third upper nozzles 51 to 53 are directed downward in
a vertical direction.
[0159] All the first to third upper nozzles 51 to 53 are connected
to one end of an upper processing liquid pipe 54. The other end of
the upper processing liquid pipe 54 is branched into a particle
removing liquid pipe 55, a preliminary cleaning liquid pipe 56, and
a deionized water pipe 57. The particle removing liquid pipe 55,
the preliminary cleaning liquid pipe 56, and the deionized water
pipe 57 are respectively connected to a particle removing liquid
supply source, a preliminary cleaning liquid supply source, and a
deionized water supply source.
[0160] Valves 55A, 56A, and 57A are respectively interposed in the
particle removing liquid pipe 55, the preliminary cleaning liquid
pipe 56, and the deionized water pipe 57. A particle removing
liquid, a preliminary cleaning liquid, and deionized water can be
switched to be respectively discharged from the first to third
upper nozzles 51 to 53 by opening or closing the valves 55A, 56A,
and 57A, and can be supplied to an upper surface of the wafer W
held in the spin chuck 1. The opening or closing of the valves 55A,
56A, and 57A is controlled by a control section 20.
[0161] The same type of processing liquid (any one of the particle
removing liquid, the preliminary cleaning liquid, and the deionized
water) is discharged from the first to third upper nozzles 51 to
53. The processing liquid discharged from the first upper nozzle 51
is supplied to the vicinity of the center of the wafer W, the
processing liquid discharged from the second upper nozzle 52 is
supplied to a portion between the center of the wafer W and a
peripheral edge thereof with respect to the radial direction of the
wafer W, and the processing liquid discharged from the third upper
nozzle 53 is supplied to the peripheral edge of the wafer W.
[0162] When the processing liquid is supplied to only the center of
the upper surface of the wafer W, as in the substrate processing
apparatus 10 shown in FIGS. 1 (a) and 1 (b) and the substrate
processing apparatus 40 shown in FIG. 8, the processing liquid
expands to flow from the center of the wafer W to the peripheral
edge thereof. Accordingly, the amount of the processing liquid
supplied per unit area of the upper surface of the wafer W is large
at the center of the wafer W, while being small at the peripheral
edge of the wafer W. When the first to third upper nozzles 51 to 53
are arranged at different positions with respect to the radial
direction of the wafer W, as in the substrate processing apparatus
50 shown in FIG. 9, a sufficiently large amount of processing
liquid per unit area can be also supplied to a region departing
from the center of the wafer W.
[0163] For example, the processing liquid discharged from the
second upper nozzle 52 is supplied, in addition to the processing
liquid discharged from the first upper nozzle 51 and flowing along
the upper surface of the wafer W, to the portion between the center
of the wafer W and the peripheral edge thereof with respect to the
radial direction of the wafer W. The processing liquid discharged
from the third upper nozzle 53 is supplied, in addition to the
processing liquid discharged from the first and second upper
nozzles 51 and 52 and flowing along the upper surface of the wafer
W, to the peripheral edge of the wafer W. Further, the first upper
nozzle 51 is arranged nearly on the central axis C of the wafer W
held in the spin chuck 1. Therefore, a sufficient amount of
processing liquid can be also supplied to the center of the upper
surface of the wafer W.
[0164] FIG. 10 is a schematic cross-sectional view showing the
configuration of a substrate processing apparatus 60 according to a
fifth embodiment of the present invention. In FIG. 10, constituent
elements corresponding to the constituent elements of the substrate
processing apparatuses 10 and 50 shown in FIGS. 1 (a) and 1 (b) and
FIG. 9 are assigned the same reference alphanumeric characters and
hence, the description thereof is not repeated.
[0165] The substrate processing apparatus 60 can respectively
supply a processing liquid to an upper surface and a lower surface
of a wafer W held in a spin chuck 1 by a plurality of nozzles.
Although the substrate processing apparatus 60 has the same
configuration as that of the substrate processing apparatus 50
shown in FIG. 9, a spin chuck 58 having a cylindrical portion 58b
provided in a standing condition from an edge of a disk-shaped spin
base 58a in place of the spin chuck 1. Chuck pins 3 are provided at
an upper end of the cylindrical portion 58b so that the wafer W can
be held at a position more distant from the spin base 58a, as
compared with the substrate processing apparatus 50 shown in FIG.
9.
[0166] First to third lower nozzles 61 to 63 are accommodated
inside the cylindrical portion 58b.
[0167] The first lower nozzle 61 is arranged nearly on a central
axis C of the wafer W held in the spin chuck 1, and the third lower
nozzle 63 is arranged below a peripheral edge of the wafer W. The
second lower nozzle 62 is arranged between the first lower nozzle
61 and the third lower nozzle 63 with respect to the radial
direction of the wafer W. All the first to third lower nozzles 61
to 63 are directed upward in a vertical direction.
[0168] A lower processing liquid pipe 64 is inserted through a
rotating shaft 4, and an upper end of the lower processing liquid
pipe 64 is branched to be connected to the first to third lower
nozzles 61 to 63. A lower end of the lower processing liquid pipe
64 is branched into an etchant pipe 65, a particle removing liquid
pipe 66, a preliminary cleaning liquid pipe 67, and a deionized
water pipe 68. The etchant pipe 65, the particle removing liquid
pipe 66, the preliminary cleaning liquid pipe 67, and the deionized
water pipe 68 are respectively connected to an etchant supply
source, a particle removing liquid supply source, a preliminary
cleaning liquid supply source, and a deionized water supply
source.
[0169] Valves 65A, 66A, 67A, and 68A are respectively interposed in
the etching liquid pipe 65, the particle removing liquid pipe 66,
the preliminary cleaning liquid pipe 67, and the deionized water
pipe 68. An etchant, a particle removing liquid, a preliminary
cleaning liquid, and deionized water can be switched to be
respectively discharged from the first to third lower nozzles 61 to
63 by opening or closing the valves 65A to 68A, and can be supplied
to a lower surface of the wafer W held in the spin chuck 1. The
opening or closing of the valves 65A to 68A is controlled by a
control section 20.
[0170] The same type of processing liquid (any one of the etchant,
the particle removing liquid, the preliminary cleaning liquid, and
the deionized water) is discharged from the first to third lower
nozzles 61 to 63. The processing liquid discharged from the first
lower nozzle 61 is supplied to the center of the wafer W, the
processing liquid discharged from the second lower nozzle 62 is
supplied to a portion between the center of the wafer W and a
peripheral edge thereof with respect to the radial direction of the
wafer W, and the processing liquid discharged from the third lower
nozzle 53 is supplied to the peripheral edge of the wafer W.
[0171] When the first to third lower nozzles 61 to 63 are arranged
at different positions with respect to the radial direction of the
wafer W, as in the substrate processing apparatus 60, a
sufficiently large amount of processing liquid per unit area of the
peripheral edge of the lower surface of the wafer W can be also
supplied. Further, the first lower nozzle 61 is arranged nearly on
a central axis C of the wafer W held in the spin chuck 1.
Therefore, a sufficient amount of processing liquid can be also
supplied to the center of the lower surface of the wafer W.
[0172] In the substrate processing apparatuses 50 and 60 shown in
FIGS. 9 and 10, flow rate adjustment valves may be respectively
interposed between the first to third upper nozzles 51 to 53 and
the upper processing liquid pipe 54 and between the first to third
lower nozzles 61 to 63 and the lower processing liquid pipe 64. In
this case, the flow rates of the processing liquids discharged from
the first to third upper nozzles 51 to 53 and the first to third
lower nozzles 61 to 63 can be individually adjusted.
[0173] Although the present invention has been described and
illustrated in detail, it is clearly understood that the same is by
way of illustration and example only and is not to be taken by way
of limitation, the spirit and scope of the present invention being
limited only by the terms of the appended claims.
[0174] This application correspond to Japanese Patent Application
Serial No. 2002-118129 filed with the Japanese Patent Office on
Apr. 19, 2002 and Serial No. 2003-47855 filed with the Japanese
Patent Office on Feb. 25, 2003, the disclosures of which are
incorporated hereinto by reference.
* * * * *