U.S. patent application number 11/272037 was filed with the patent office on 2006-07-27 for substrate processing method and substrate processing apparatus.
Invention is credited to Hiroyuki Mori, Mitsunori Nakamori, Takayuki Niuya, Takehiko Orii, Hiroshi Yano.
Application Number | 20060163205 11/272037 |
Document ID | / |
Family ID | 19162619 |
Filed Date | 2006-07-27 |
United States Patent
Application |
20060163205 |
Kind Code |
A1 |
Niuya; Takayuki ; et
al. |
July 27, 2006 |
Substrate processing method and substrate processing apparatus
Abstract
A resist film and a polymer layer adhered on a semiconductor
substrate can be removed by the method according to the present
invention. A first processing liquid, typically including a
oxidizing agent, such as hydrogen peroxide solution, is fed to the
substrate, thereby the condition of the resist film and the polymer
layer is changed. Next, a second processing liquid, typically
including a dimethyl sulfoxide and an amine solvent, is fed to the
substrate, thereby the resist film and the polymer layer is
dissolved and lifted off from the substrate. A sputtered copper
particles included in the polymer layer can also be removed.
Inventors: |
Niuya; Takayuki; (Tokyo-To,
JP) ; Orii; Takehiko; (Nirasaki-Shi, JP) ;
Mori; Hiroyuki; (Nirasaki-Shi, JP) ; Yano;
Hiroshi; (Nirasaki-Shi, JP) ; Nakamori;
Mitsunori; (Nirasaki-Shi, JP) |
Correspondence
Address: |
Smith, Gambrell & Russell
Suite 800
1850 M Street, N.W.
Washington
DC
20036
US
|
Family ID: |
19162619 |
Appl. No.: |
11/272037 |
Filed: |
November 14, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10295041 |
Nov 15, 2002 |
6979655 |
|
|
11272037 |
Nov 14, 2005 |
|
|
|
Current U.S.
Class: |
216/83 ;
156/345.11; 216/100; 257/E21.228; 257/E21.255; 257/E21.256;
438/745; 438/749 |
Current CPC
Class: |
H01L 21/02063 20130101;
H01L 21/67017 20130101; H01L 21/67028 20130101; G03F 7/422
20130101; H01L 21/31138 20130101; H01L 21/31133 20130101; H01L
21/76814 20130101 |
Class at
Publication: |
216/083 ;
438/745; 438/749; 156/345.11; 216/100 |
International
Class: |
B44C 1/22 20060101
B44C001/22; H01L 21/306 20060101 H01L021/306; C23F 1/00 20060101
C23F001/00; H01L 21/302 20060101 H01L021/302; C25F 3/00 20060101
C25F003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 15, 2001 |
JP |
2001-350035 |
Claims
1-22. (canceled)
23. A substrate processing apparatus comprising: an enclosure
defining a processing space in which a substrate is processed; a
substrate holder adapted to hold the substrate in the processing
space; a first chemical liquid supply source that holds a first
chemical liquid for altering a condition of a resist film to
produce an altered resist film; a second chemical liquid supply
source that holds a second chemical liquid for dissolving the
altered resist film; a first chemical liquid line connecting the
first chemical liquid supply source to the processing space through
a first valve; a second chemical liquid line connecting the second
chemical liquid supply source to the processing space through a
second valve; and a controller that controls the first valve and
the second valve such that the first chemical liquid is supplied to
the processing space through the first valve, and thereafter the
second chemical liquid is supplied to the processing space through
the second valve.
24. The apparatus according to claim 23, wherein the first
processing liquid further has an ability of oxidizing a sputtered
metal, and the second processing liquid further has an ability of
dissolving the sputtered metal oxidized by the first processing
liquid.
25. The apparatus according to claim 23, further comprising an
inert gas feeder that supplies an inert gas to establish a
non-oxidizing atmosphere in the processing space.
26. The apparatus according to claim 23, wherein the substrate
holder comprises a rotor adapted to rotate the substrate while
holding the same.
27. The apparatus according to claim 26, further comprising a
controller for controlling a rotational speed of the rotor.
28. The apparatus according to claim 23, wherein: the enclosure
includes an outer enclosing element defining a first processing
space therein and an inner enclosing element defining a second
processing space therein, the inner enclosing element being adapted
to move into and out of a space inside the outer enclosing element,
said apparatus further comprising a first nozzle that sprays the
first chemical liquid into one of the first and second processing
spaces, and a second nozzle that sprays the second chemical liquid
into the other of the first and second processing spaces.
29. The apparatus according to claim 23, wherein the first chemical
liquid supply source comprises a tank that stores the first
chemical liquid, said apparatus further comprising: a first
chemical liquid recovering line through which the first chemical
liquid supplied to the processing space is returned to the tank;
and a concentration sensor, provided in the tank or the first
chemical liquid recovering line, that determines a concentration of
an active component of the first chemical liquid.
30. The apparatus according to claim 23, wherein the second
chemical liquid supply source comprises a tank that stores the
second chemical liquid, said apparatus further comprising: a second
chemical liquid recovering line through which the second chemical
liquid supplied to the processing space is returned to the tank;
and a concentration sensor, provided in the tank or the second
chemical liquid recovering line, that determines a concentration of
an active component of the second chemical liquid.
31. The apparatus according to claim 23, wherein the first chemical
liquid supply source comprises a tank that stores the first
chemical liquid, said apparatus further comprising: a first
chemical liquid recovering line through which the first chemical
liquid supplied to the processing space is returned to the tank;
and a new liquid feed line through which a new first chemical
liquid is supplied to the tank, the controller adjusting an amount
of the first chemical liquid to be returned to the tank and an
amount of the new first chemical liquid to be supplied to the tank
so that an ability of the first processing liquid, existing in the
tank, to alter the resist film is maintained.
32. The apparatus according to claim 23, wherein the second
chemical liquid supply source comprises a tank that stores the
second chemical liquid, said apparatus further comprising: a second
chemical liquid recovering line through which the second chemical
liquid supplied to the processing space is returned to the tank;
and a new liquid feed line through which a new second chemical
liquid is supplied to the tank, the controller adjusting an amount
of the second chemical liquid to be returned to the tank and an
amount of the new second chemical liquid to be supplied to the tank
so that an ability of the second processing liquid, existing in the
tank, to alter the resist film is maintained.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a substrate processing apparatus
and substrate processing method for removing, utilizing a
processing liquid, adhesives such as resist, polymers, etc., which
adhere to the substrate during the process of the substrate, such
as semiconductor device manufacturing process.
[0003] 2. Description of the Related Art
[0004] Recently, in the process of manufacturing semiconductor
devices, the miniaturization of design rules has rapidly
progressed. Along with this has come the use of a
low-dielectric-constant organic film as an interlayer insulating
film called low-k film, and the use of Cu having low electrical
resistance as a wiring-layer material instead of Al, in view of the
high speed operation of the semiconductor devices.
[0005] Dual damascene process has been utilized to form Cu wiring
layers with the interlayer insulating film being arranged between
the adjacent Cu wiring layers. The dual damascene process, for
example, is carried out in the following order. A stop layer is
formed on the already-formed Cu wiring layer in the damascene
structure of the under level, and on the stop layer a low-k
interlayer insulating film is formed. On the interlayer insulating
film, a resist film is formed according to a predetermined pattern.
Via-etching is carried out by using the resist film as a mask.
Then, after the resist film and the polymers in the hole are
removed, a sacrifice layer is formed. Once again, a resist film
with a specific pattern is formed on the interlayer insulating
film, and trench etch is carried out by using the resist film as a
mask. Then the resist and polymers in the hole are removed. Then,
after the sacrifice layer and the stopper layer are removed by
etching, a top Cu wiring or a plug is formed.
[0006] The removal of the aforementioned resist and polymers is
conducted by performing wet cleaning after dry ashing. This is
because, it is not possible, until now, to completely remove the
resist and the polymer only through the application of wet
cleaning, utilizing a processing liquid.
[0007] However, when dry ashing is conducted at the step of
removing resist after the manner of pattern processing, damage is
done to the low-k film that is the interlayer insulating film,
causing a variety of problems with integration with the Cu
wiring.
SUMMARY OF THE INVENTION
[0008] The objective of the present invention, developed in
consideration of the aforementioned problems, is to provide a
method and apparatus for removing a resist and a polymer layer
without damaging the underlying layer.
[0009] To attain the above objective, the present invention
provides a substrate processing method, which includes: a step of
preparing a substrate on which objects to be removed are adhered,
the objects including a resist film and a polymer layer; a step of
supplying a first processing liquid onto a substrate in such a
manner that the first processing liquid flows on a surface of the
substrate, thereby altering the condition of the objects; and a
step of supplying a second processing liquid onto a substrate in
such a manner that the second processing liquid flows on a surface
of the substrate, thereby dissolving the objects thus altered by
the first processing liquid and lifting them off from the
substrate.
[0010] The objects to be removed from the substrate may include a
sputtered metal. In this case, the metal is oxidized by the first
processing liquid in the step of supplying the first processing
liquid, and the step of supplying the second processing liquid is
carried out while avoiding oxidation of the substrate.
[0011] According to the second aspect of the present invention, a
substrate processing apparatus is provided, which includes: a rotor
adapted to hold the substrate; an enclosure defining a processing
space configured to accommodate the rotor; means for supplying a
first processing liquid to the substrate, the first processing
liquid having an ability of altering a condition of objects to be
removed that are adhered on the substrate, the objects including a
resist film and a polymer layer; means for supplying a second
processing liquid to the substrate, the second processing liquid
having an ability of dissolving the objects and lifting off the
objects.
[0012] The objects to be removed from the substrate may further
include a sputtered metal. In this case, the first processing
liquid further has an ability of oxidizing the metal, and the
second processing liquid further has an ability of dissolving the
sputtered metal oxidized by the first processing liquid.
[0013] Preferably, the apparatus further include an inert gas
feeder that supplies an inert gas to establish a non-oxidizing
atmosphere in the processing space.
[0014] The above and other objectives, features, and advantages of
the present invention will be apparent from the following detailed
description of the preferred embodiments of the invention in
conjunction with the accompanying drawings.
BREIF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a cross-sectional view of the wafer processing
apparatus, in which the inner cylinder is imposed on the outer
pipe;
[0016] FIG. 2 is a cross-sectional view of the processing apparatus
displaying the status in which the inner cylinder is in the
position of being removed to the exterior of the outer
cylinder;
[0017] FIG. 3 is a cross-sectional view of the processing apparatus
taken along the line A-A shown in FIG. 1;
[0018] FIG. 4 is an enlarged cross-sectional view of the switching
mechanism of the processing apparatus of FIG. 1, and parts disposed
adjacent to the switching mechanism;
[0019] FIG. 5 is an enlarged cross-sectional view of the seal
mechanism of the processing apparatus of FIG. 1, and parts disposed
adjacent to the switching mechanism;
[0020] FIG. 6 is an illustration schematically showing the
structure of the first processing liquid supply mechanism of the
processing apparatus;
[0021] FIGS. 7(a) to 7(c) are illustrations of filter devices that
are attached to the recycle pipe of the first processing liquid
supply mechanism of the processing apparatus shown in FIG. 6;
[0022] FIG. 8 is a cross-sectional view of another embodiment of a
processing liquid tank of the first processing liquid supply
mechanism of the processing apparatus of FIG. 1;
[0023] FIGS. 9(a) to 9(d) are cross-sectional views showing an
example of the manufacturing process of a semiconductor device, to
which the processing method according to the present invention is
applied; and
[0024] FIG. 10 is a cross-sectional view of another example of the
semiconductor device, to which the processing method according to
the present invention is applied.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] The processing apparatus 1 according to the present
invention is used for the removal of resist layers, polymer layers
that are residual of the etching process, and metallic sputter,
after the semiconductor wafer (hereinafter referred to as simply
"wafer") W has been subjected to the etching process. As shown in
FIGS. 1 thru 3, A motor 3 is affixed to a vertical support wall 2
of the processing apparatus 1 via a support member 2a in such a
manner that the revolving shaft 4 of the motor 3 faces a horizontal
direction. A rotor 5 is attached to the shaft 4 of the motor 3. A
tubular casing 6 extends in a horizontal direction from the support
wall 2, and surrounds the motor 3 and the shaft 4. The casing 6
support first enclosure forming members 7 and second enclosure
forming members 8 adapted to enclose the rotor 5.
[0026] The rotor 5 is configured to hold a plurality of wafers W
(for example 26 pieces) that are stood vertically and aligned in a
horizontal direction. The motor 3 rotates the rotor 5, along with
the held plurality of wafers W.
[0027] The first enclosure forming members 7 include a vertical
wall 7a located near the motor 3, a vertical wall 7b located
further from the motor 3 and an outer cylinder 7c that is provided
around the rotor 5, ensuring a clearance between the rotor 5 and
the outer cylinder 7c. In the central portion of the vertical wall
7b, the revolving shaft 4 which penetrates the vertical wall 7b,
and a sealing mechanism 90 (explained in detail later) which seals
the space between the vertical wall 7b and the revolving shaft 4,
are provided. The outer cylinder 7c can retract on the casing 6
side when mounting the wafers W onto the rotor 5.
[0028] The second enclosure forming members 8 include an inner
cylinder 8a, the diameter of which is smaller that that of the
outer cylinder 7c. The inner cylinder 8a can transit between the
liquid processing position depicted in FIG. 1 and the retracted
position depicted in FIG. 2. When the inner cylinder 8a is in the
liquid processing position within the outer cylinder 7c as shown in
FIG. 1, a processing space 30 is defined by the inner cylinder 8a
and the vertical walls 7a and 7b (in other words the second
enclosure forming members 8). When the inner cylinder 8a is in the
retracted position and the outer cylinder 7c is in the liquid
processing position as shown in FIG. 2, a processing space 20 is
defined by the first enclosure forming members 7. The processing
space 20 and the processing space 30 are made airtight by a sealing
mechanism, not shown.
[0029] Two spray nozzles 22 (see FIG. 3), which have a number of
spray outlets 21, are attached horizontally to the upper end
portion of the outer cylinder 7c defining the processing space 20.
Connected to the spray nozzle 22 is a pipe 23, to which a first
processing liquid supply mechanism 25, which supplies a first
processing liquid, is connected via a valve 24. The first
processing liquid, which flows through the pipe 23 from the first
processing liquid supply mechanism 25, is sprayed from the spray
outlets (nozzle openings) 21 of the spray nozzle 22. The first
processing liquid has an ability of altering the condition of the
resist film and the polymer layers, and further serves to oxidize
sputtered metals such as Cu particles. The first processing liquid
is primarily made up of an inorganic chemical liquid that contains
an oxidizing agent such as hydrogen peroxide solution. The first
processing liquid functions to alter the surface layers of the
resist film and the polymer layers from a hydrophobic state to a
hydrophilic state.
[0030] Two spray nozzles 32 (refer to FIG. 3), which have a number
of spray outlets 31, are attached horizontally to the upper end
portion of the inner cylinder 8a that defines the processing space
30. Connected to the spray nozzle 22 is a pipe 33, to which a
second processing liquid supply mechanism 35, which supplies a
second processing liquid, is connected via a valve 34. The second
processing liquid, which flows through the pipe 33 from the second
processing liquid supply mechanism 35 is sprayed from the spray
outlets 31 of the spray nozzle 32. The second processing liquid
comprises an organic chemical liquid that serves to dissolve and
lift off the resist film, the polymer layers, and the metals that
were oxidized by the first processing liquid. The second processing
liquid contains, for example, dimethyl sulfoxide (DMSO) and amine
solvent.
[0031] Pure water and isopropyl alcohol (IPA) can be sprayed from
the spray nozzles 22 and 32, via the pipes 23 and 33, respectively.
A pipe 41 extends from a pure water supply mechanism 42, and from
the pipe 41 diverge pipes 41a and 41b, which are connected to the
pipes 23 and 33, respectively. A pipe 45 extends from an isopropyl
alcohol (IPA) supply mechanism 46, and from the pipe 45 diverge
pipes 45a and 45b, which are connected to pipes 23 and 33,
respectively. Thus, pure water flows from the pure water supply
mechanism 42 through the pipe 41 to the pipe 41a and the pipe 41b,
and is supplied by both the pipes 23 and 33, respectively. IPA
flows from the IPA supply mechanism 46 through the pipe 45 to the
pipe 45a and the pipe 45b, and is supplied by both the pipe 23 and
the pipe 33, respectively. Valves 43, 44, 47 and 48 are provided on
the pipes 41a, 41b, 45a and 45b, respectively. In addition, a valve
controller 49 controls the opening and closing of valves 24, 34,
43, 44, 47 and 48. The valve controller 49 is controlled by a
process controller 100, which controls the entire processing of the
wafers W.
[0032] Protruding from an exterior side of a central portion of the
vertical wall 7b is a protruding part 50, to which two exhaust
ports 51 and 52 are connected. These exhaust ports 51 and 52 are
used to exhaust the processing space 20 and the processing space
30, respectively. Closing mechanisms for both ports 51 and 52 are
provided inside the protruding part 50.
[0033] At the vertical wall 7b, on the exterior side of protruding
part 50, two N.sub.2 gas introduction ports 53a and 53b are
provided to introduce N.sub.2' gas (inert gas) to at least the
processing space 30 that is formed inside the inner cylinder 8a.
Gas supply pipes 54a and 54b are connected to the N.sub.2 gas
introduction ports 53a and 53b, respectively. N.sub.2 gas is
supplied from an N.sub.2 gas supply source 55 to the processing
space 30 through the gas supply pipes 54a and 54b and the N.sub.2
gas introduction ports 53a and 53b, respectively. Of course, with
the inner cylinder 8a in the retracted position, the N.sub.2 gas
may also be provided via the N.sub.2 gas introduction ports 53a and
53b to the processing space 20 that is formed inside the outer
cylinder 7c. A heater 55a for heating the N.sub.2 gas is attached
to the N.sub.2 gas supply source 55.
[0034] By elevating the temperature inside the processing space 30
by supplying heated N.sub.2 gas thereto, it is possible to enhance
the dissolving action of the processing liquid. To each of the gas
supply pipes 54a and 54b, mass-flow controllers 56a and 56b and
valves 57a and 57b are provided. Gas supply pipes 58a and 58b are
connected to the N.sub.2 gas supply source 55. The gas supply pipe
58a is connected to a switching mechanism 90, to be explained
later, that is provided at a central area of the vertical wall 7a.
The gas supply pipe 58b is connected to a sealing mechanism 90, to
be explained later, that is provided at a central area of the
vertical wall 7a. To each of the gas supply pipes 58a and 58b,
mass-flow controller 59a and 59b and valves 60a and 60b are
provided. The inert gas is not limited to N.sub.2 gas, but may be
Ar gas or any other kind of inert gas.
[0035] A ring 61 is provided around the exterior of the vertical
wall 7b. Provided at the bottom of the ring 61 is a first drain
port 62, which discharges processing liquid, pure water or IPA used
in the processing space 20 defined by the outer cylinder 7c in the
processing position depicted in FIG. 2. Drainpipe 63 is connected
to the first drain port 62. The bottom of the inner cylinder 8a is
inclined toward the motor 3. Provided at the bottom of the inner
cylinder 8a is a second drain port 64, which is located at the
vertical wall 7a side end of the inner cylinder 8a when it is
positioned at the processing position as shown in FIG. 1. The
second drain port 64 discharges used processing liquid, pure water
or IPA from the processing space 30. A drainpipe 65 is connected to
the second drain port 64. It is possible to recycle liquids
discharged through these drainpipes 63 and 65.
[0036] The rotor 5 is equipped with: a pair of discs 70a and 70b,
positioned with a space therebetween; a pair of first fixed bars
71a and 71b and a pair of second fixed bars 72a and 72b, the ends
of which are securely fixed to the discs 70a and 70b; and a pair of
support mechanisms 73a and 73b, which support, from the bottom, the
wafers W engaged by fixed bars 71a, 71b, 72a, and 72b. Each of the
fixed bars 71a, 71b, 72a, and 72b have a plurality of grooves (not
shown), into which the edges of wafers Ware inserted. Pressure
sensors are attached to one of the fixed bars 71a, 71b, 72a, and
72b.
[0037] Support mechanism 73a has an arm 74a positioned at the
inside of disc 70a, an arm 75a positioned at the inside of disc
70b, and a mobile support bar 76a, which is linked to arm 74a and
arm 75a and supports the wafers W. Balance weights 77a (disc 70b
side shown only) are provided to arms 74a and 75a, respectively, in
such a manner that each disk is located between the balance weight
and the corresponding arm. Support mechanism 73b is constructed in
the same fashion, having a mobile support bar 76b that supports the
wafers W.
[0038] Switching mechanisms 80 are provided on the support
mechanism 73a side and the support mechanism 73b side,
respectively. The latter has a switching part 81a as shown in FIG.
4. By rotating the switching part 81a, the balance weight 77a can
be turned, which causes the arm 75a to turn the support bar 76a.
The former, namely the switching mechanism on the support mechanism
73b side, is constructed in the same fashion, and the support bar
76b is turned the same way. Accordingly, switching between having
the wafers W in a supported state and the support being released in
a released state can be done via the two switching mechanisms
80.
[0039] As can be seen in FIG. 4, the switching part 81a is received
by an opening 82a, which is provided in the vertical wall 7a.
Arranged on the motor 3 side of the opening 82a is a boss 83, in
which a through hole following the opening 82a is formed. The
switching part 81a is inserted into the through hole of the boss 83
so as to have only a slight clearance 84. A space 85 exists between
the tip of the switching part 81a and the opening 82a. A revolving
cylinder 86 is provided on the motor 3 side of the boss 83. The
switching part 81a is linked to the revolving cylinder 86, and can
be rotated by the movement of the revolving cylinder 86. A
ring-shaped passage 87 is formed in the boss 83, and the previously
described gas supply pipe 58a is connected to a part of this
passage 87. Provided in the boss 83 is a narrow ring-shaped passage
88, which is connected to the passage 87 and extends toward the
processing space 20 and the processing space 30. This passage 88 is
connected to the space 85 between the switching part 81a and the
vertical wall 7a. By feeding N.sub.2 gas through the gas supply
pipe 58a, the N.sub.2 gas passes through the passage 88 from the
passage 87 and flows into either processing space 20 or 30 from the
space 85. In this manner, supply of N.sub.2 gas allows for
supplementary adjustments to be made to the atmosphere of the
processing space 30, or if needed, processing space 20.
[0040] It is also possible to prevent the processing liquid from
remaining in the space 85 between the switching part 81a and the
vertical wall 7a. If the liquid remains and dries to from
particles, it could cause the wafer to become polluted, but by
preventing the liquid from remaining in the space 85, this type of
problem disappears.
[0041] Next, the seal mechanism 90 provided at the central area of
vertical wall 7a will be explained. FIG. 5 is an enlarged
cross-sectional view showing the detailed arrangement of the seal
mechanism 90 and surrounding area, which is simplified in FIG.
1.
[0042] As shown in FIG. 5, provided at the central area of vertical
wall 7a is a hollow, cylindrical body 91, which encloses the
revolving shaft 4. Between the tip of the cylindrical body 91a and
the revolving shaft 4, a slight clearance 92 is provided. Between
the cylindrical body 91 and the revolving shaft 4, a bearing 93
that allows the shaft 4 to rotate thereon, and a liquid sealing
member 9 that seals a space between the cylindrical body 91 and the
shaft 4, are provided. A ring-shaped passage 94 is arranged between
the cylindrical body 91 and the bearing 93. Connected to the
passage 94 are the gas supply pipe 58b for supplying N.sub.2 gas
into the passage 94 and a gas exhaust pipe 58c for discharging the
gas from the passage 94.
[0043] The passage 94 is connected to the processing spaces 20 and
30 via the clearance 92. With such a construction, by feeding
N.sub.2 gas through gas supply pipe 58b, the N.sub.2 gas passes
through the clearance 92 from the passage 94 and flows into either
processing space 20 or 30. By doing so, supply of the N.sub.2 gas
not only allows for supplementary adjustments to be made to the
atmosphere of the processing space 30, or if needed, processing
space 20, but also serves to prevent the processing liquid from
remaining in the clearance 92 surrounding the revolving shaft
4.
[0044] The motor 3, which rotates the rotor 5, is controlled by
motor controller 66, and can adjust the rotation speed of the rotor
5 to a desired rotation speed. Also, during processing, the
rotation speed of rotor 5 can be changed at will, for example, the
rotation speed of rotor 5, in other words that of the wafers W, can
be sped up or slowed down repeatedly. The motor controller 66 is
controlled by the process controller 100, described above.
[0045] Next, first processing liquid supply mechanism 25 will be
explained. FIG. 6 is a diagram schematically showing the structure
of the first processing liquid supply mechanism 25. The first
processing liquid supply mechanism 25 has a processing liquid tank
101, which holds the first processing liquid. The processing liquid
tank 101 is a dual formation of a new liquid tank 102 on the
inside, which holds new processing liquid, and a recycle tank 103
on the outside, which holds used processing liquid. The end portion
of the pipe 23 is inserted into the new liquid tank 102 of the
processing liquid tank 101. From a processing liquid supply pump
104 that is provided on the pipe 23, new liquid in the new liquid
tank 102 is supplied to processing space 20 in the outer cylinder
7c via the pipe 23 and the spray nozzle 22. Provided at the
downstream side of the processing liquid supply pump 104 is a
switch valve 105, which is connected to a pipe 106. The pipe 106 is
inserted into the recycle tank 103 of the processing liquid tank
101. Upon switching the switch valve 105 from the pipe 23 side to
the pipe 106 side, used liquid in the recycle tank 103 is supplied
to the processing space 20 in the outer cylinder 8a a via the pipe
106, the pipe 23 and the spray nozzle 22.
[0046] Inserted into the new liquid tank 102 of the processing
liquid tank 101 is a new liquid supply pipe 107, to which a new
liquid supply source 108 is connected. A new liquid supply pump 109
is provided on the new liquid supply pipe 107. A sensor (not shown)
detects the level of the processing liquid in the new liquid tank
102. Based on detection by the sensor, new liquid can be supplied
to the new liquid tank 102 from the new liquid supply source 108
via the new liquid supply pump 109, so as to keep the liquid level
within a desired range.
[0047] Arranged on the pipe 107 are an open/close valve 110 and a
switch-valve 111, the latter 111 being located the downstream side
of the former 110. Connected to the switch valve 111 is a pipe 112,
which is inserted into the recycle tank 103. By switching this
switch valve 111, it is possible to supply new processing liquid to
the recycle tank 103 as well. A connecting passage (not shown) runs
from the upper parts of the new liquid tank 102 to the recycle tank
103, so that any overflow of the processing liquid supplied to new
liquid tank 102 flows into recycle tank 103.
[0048] The drainpipe 63, which is connected to the aforementioned
first drain port 62, is connected to a switch valve 113. The switch
valve 113 is connected to a pipe 114, which is inserted into the
recycle tank 103 of the processing liquid tank 101. Upon switching
the switch valve 113, it is possible for used first processing
liquid that flows though the drainpipe 63 to be collected or
recovered in the recycle tank 103 via the pipe 114. In the case
that the liquid is not to be collected, by switching switch valve
133 to the drainpipe 63 side, the liquid can be discharged. In
addition, used pure water, IPA etc., or uncollected first
processing liquid that flows through drainpipe 63 can be disposed
of separately due to the provision of a series of switch valves
(not shown) at the downstream side of the switch valve 113.
[0049] Provided at the upstream side of the switch valve 113 on the
drainpipe 63 are a concentration sensor 115 and a filter device
116, the latter 116 being located the upstream side of the former
115. The ability of the first processing liquid to process the
wafer W is dependent on the concentration of the active components
in the processing liquid. Thus, when the first processing liquid is
collected, said concentration of the used first processing liquid
is measured by the concentration sensor 115 as it flows through
drainpipe 63. If said concentration is lower than an allowable
level, adjustment of said concentration is carried out by the
provision of new first processing liquid to the recycle tank 103
through pipe 112.
[0050] In the event that the concentration of the active components
of the used first processing liquid becomes even lower to the point
that it cannot be used, it is disposed of without being collected,
by switching the switch valve 113. For a time after the initiation
of processing in the processing space 20 in the outer cylinder 7c,
waste liquid with a high degree of pollutant is discharged, and so
is not collected and disposed of regardless of said concentration
level. Instead of providing the concentration sensor 115, the
timing for adjusting said concentration or disposing the used first
processing liquid without collection may also be determined by
calculation of the relationship between the number of times
recycled and the concentration level. All of these controls are
carried out by the process controller 100. The controller 100 also
functions to control the amount of the new first processing liquid
provided and the amount of the used first processing liquid
recycled, so as to maintain the processing effectiveness of the
first processing liquid in the recycle tank 103. In such an
instance, when the processing effectiveness of the liquid in the
recycle tank 103 falls below a determined level, the controller 100
sets the collection amount to zero, in other words does not attempt
the recovery of the used first processing liquid.
[0051] The filter device 116 functions mainly to remove particles
or other solids that mix with the discharge liquid as a result of
the process to remove the resist film or the polymer layers. The
filter device 116 may be comprised of a simple filter element.
However, since the lifting-off of the resist film or the polymer
layers may generate relatively large solids (particles), it is
preferable to position a coarse filter element 117 on the upstream
side and a fine filter element 118 on the downstream side, as shown
in FIG. 7(a). Also, as shown in FIG. 7 (b), it is also preferable
to place identically-designed filter elements 119a and 119b in
parallel. This makes it possible to conduct maintenance on one
filter element, such as replacement, etc., while the other filter
element is in use. Reference numerals 120 and 121 designate switch
valves. As indicated in FIG. 7 (c), it is also preferable to
arrange a combination of the course filter element 117a and the
fine filter element 118a and a similarly constructed combination of
the course filter element 117b and the fine filter element 118b, in
parallel. In this case, it is possible to achieve the same benefits
as the constructions shown in the aforementioned FIGS. 7(a) and
7(b).
[0052] A second processing liquid supply mechanism 35, which
supplies a second processing liquid, is constructed exactly the
same as the above-described first processing liquid supply
mechanism 25, and is similarly controlled by process controller
100. Accordingly, a repetitive explanation has been omitted.
[0053] The processing liquid tank may be configured so that it has
dual recycle tanks. FIG. 8 shows such a processing liquid tank
101'. This process tank 101' has a new liquid tank 102 on the
innermost side, outside of this a first recycle tank 103a, and
further to the outside is provided a second recycle tank 103b. In
such a case, the pipe 114, which extends from switch valve 113 on
the recycle pipe 63, joins with a pipe 114a inserted into the first
recycle tank 103a, and a pipe 114b that is inserted into the second
recycle tank 103b. Used processing liquid can be supplied to either
the first or the second recycle tanks 103a and 103b by switching
switch valve 122. In order to allow the processing liquid in the
first or the second recycle tanks 103a and 103b to be supplied to
the processing space 20 in the outer cylinder 7c, pipes 106a and
106b are inserted into the tanks 103a and 103b, respectively. With
this type of construction like liquid tank 101', the processing
liquid may be recycled from the first recycle tank 103a for the
first half of the processing period, and for the latter half
recycled from the second recycle tank 103b. Thereby, pollution of
the liquid of the second recycle tank 103b is reduced, and the
total amount of new liquid used can be reduced as well.
[0054] Next, the processing of substrates by using the
above-described processing apparatus 1 will be described. As a
first example, the liquid processing to be carried out after a via
hole, which reaches to an underside Cu wiring layer, is formed in a
low-k film made from an organic material with a low dielectric
constant by using a patterned resist film, i.e., a resist mask.
[0055] Before explaining the liquid processing, the process steps
of via-etching will be described with reference to FIG. 9. Firstly,
as shown in FIG. 9 (a), on the Cu wiring layer 171 inside the
damascene structure 170, a stopper layer 172 and a low-k film 173
serving as an insulating layer are formed. Next, on top of the
low-k film 173, a resist film 174 is formed. A wiring pattern is
transferred onto the resist film 174 utilizing photolithography
technology.
[0056] Next, as shown in FIG. 9 (b), using a plasma of etching gas,
a via-hole 175 is formed by utilizing the resist film 174 as a
mask. At this time, due to the components of the etching gas, a
polymer layer 176 is formed on the inner walls of the via-hole 175.
Then, at the time of etching, the polymer layer 176 functions as a
protective layer and thus etching with a high degree of anisotropy
can be achieved.
[0057] As etching progresses and reaches the Cu wiring layer 171 as
shown in FIG. 9 (c), Cu is sputtered, resulting in Cu particles 177
adhereing to the outer side of polymer layer 176. After the etching
has reached the Cu wiring layer 171 over-etching is conducted, and
a polymer layer 176 is again formed on the outside of Cu particle
177, as shown in FIG. 9 (d). In other words, the Cu particles 177
are trapped inside the polymer layers 176.
[0058] In the state depicted in FIG. 9 (d), the wafer W will be
processed by the processing apparatus 1. As will be explained
hereafter, due to this processing, the resist film 174, the polymer
layers 176 and the Cu particles 177 will all be removed.
[0059] During this processing, firstly, with outer cylinder 7c and
inner cylinder 8a retracted above the casing 6, by a conveying
means not shown, a plurality of wafers W are placed on the rotor 5
from below, and are supported by the support arms 73a and 73b. At
this time, the previously mentioned pressure sensor measures the
pressure exerted on the wafers W as they are places on rotor 5,
thereby avoiding damage to wafers W. Then, outer cylinder 7c is
arranged outside the rotor 5, forming the airtight processing space
20, as shown in FIG. 2.
[0060] Next, as the wafers W are rotated due to the rotation of the
rotor 5 by the motor 3, a first processing liquid, for example,
made up of an inorganic chemical whose primary component is an
oxidizing agent such as hydrogen peroxide solution, etc, is sprayed
from the nozzle 22. As a result, the first processing liquid is
supplied to the wafers W. Subsequently, the condition of the resist
film 174 and the polymer layers 176 is altered, forming cracks
which makes it easy for the processing liquid to penetrate, also
oxidizing the sputtered Cu particles 177. In addition, the surface
layers of the resist film 174 and the polymer layers are altered
from a hydrophobic state to a hydrophilic state. At this time,
since the sputtered Cu particles 177 react highly due to the
influence of impurities contained therein, only the sputtered Cu
particles are selectively oxidized, while the underlying Cu wiring
layer 171 is not oxidized.
[0061] During the processing with the first processing liquid,
while spraying the first processing liquid, by rotating the rotor 5
at a low speed in the range of 1 to 500 rpm for the first several
tens of seconds. Thereby, the first processing liquid is spread
over the surfaces of the wafers W. In this case, the speed of
revolution of the rotor 5 can be used to control how evenly the
first processing liquid is spread, based on its viscosity. After
the first processing liquid spreads, the revolution speed of the
rotor 5 is increased to a high speed in the range of 100 to 3000
rpm, thereby heightening the reactivity. From the standpoint of
heightened reactivity, it is preferable to repeatedly alternate
between low-speed and high-speed revolutions.
[0062] The atmosphere in the first process space 20 may be an air
atmosphere. However, in order to completely avoid the oxidization
of the Cu wiring layer 171, it is preferable that N.sub.2 gas be
fed to the first process space 20 from the supply source 55 to
establish an inert gas atmosphere in the first process space
20.
[0063] The first processing liquid used in the processing is
discharged though the first drain port 62 to the drainpipe 63, and
collected in the recycle tank 103 of the processing liquid tank
101. As needed, in the time between the completion of processing
with the first processing liquid and the start of processing with
the second processing liquid, a new first processing liquid is
supplied to the new liquid tank 102 from the new liquid source 108.
Then, any overflow from the new liquid tank 102 is supplied to the
recycle tank 103.
[0064] Next, inner cylinder 8a that was retracted above the casing
6 is moved to the inside of the outer cylinder 7c, as shown in FIG.
1, thereby forming the second process space 30 inside the inner
cylinder 8a, and preparation for processing with a second
processing liquid is thus carried out.
[0065] In this state, as needed, it is possible to conduct a rinse
process by applying pure water or IPA to the wafers W as a rinse
liquid while the wafers W are rotated on the rotor 5. Also, after
the pure water or the IPA has been applied to the wafers W, a
drying process may be conducted by spinning off the rinse liquid
through high-speed rotation of the rotor 5.
[0066] After this type of rinse process is carried out, a second
processing liquid is fed to the wafers W in the second process
space 30. Immediately after supply of a second processing liquid
has begun, the rinse liquid remaining in the second process space
30 is mixed with the second processing liquid, and the mixture is
discharged from the second process space 30. As the second
processing liquid is diluted by the rinse liquid, in the event that
the mixture is collected in the processing liquid tank (hereinafter
referred to as "second processing liquid tank") of the second
processing liquid supply mechanism 35, it is likely that the
concentration of the active component of the second processing
liquid in the second processing liquid tank will be reduced.
Accordingly, in such a case, a new second processing liquid is
supplied to the second processing liquid containing in the second
processing liquid tank. However, when doing so, it is preferable to
control the amount of discharged liquid (i.e., the mixture of the
second processing liquid and the rinse liquid) collected into the
tank and the amount of the new second processing liquid added into
the second processing liquid tank, in order to maintain the process
effectiveness by the second processing liquid.
[0067] Specifically, based on the amount of the new second
processing liquid supplied to the recycle tank of the second liquid
process tank, collection of the discharge liquid should be
controlled so that the concentration of the active component of the
second processing liquid in the recycle tank of the second
processing liquid tank becomes higher than prescribed. In this
case, is the collection of discharge liquid would cause the
processing ability of the processing liquid in the recycle tank to
fall below a desired level, control should be set to have
collection amount be zero, in other words, the mixture of the
second processing liquid and the rinse liquid should not be
collected.
[0068] During processing with the second processing liquid, from
the standpoint of preventing oxidation of the Cu wiring layer 171,
a non-oxidizing atmosphere, typically an inert atmosphere, is
needed. Accordingly, prior to the supply of the second processing
liquid, inert gas N.sub.s gas is supplied to the process space 30
from the N.sub.s gas supply source 55, thereby establishing an
inert gas atmosphere in the second process space 30. In the case
where N.sub.s gas was supplied to the first process space 20 during
the processing with the first processing liquid, the supply of the
N.sub.s gas is continued to maintain the inert gas atmosphere.
[0069] In this state, as the rotor 5 is rotated by the motor 3, in
turn rotating the wafers W, and a second processing liquid, for
example, an organic chemical comprised of dimethyl sulfoxide (DMSO)
and amine solvent, is released from the spray nozzle 32, and thus
applied to the wafers W. Due to the provision of the second
processing liquid, the resist film 174, the polymer layers 176 and
the oxidized Cu particles 177 are dissolved and lifted off.
[0070] Simply applying the second processing liquid without using
the first processing liquid would not be successful, as the second
processing liquid will hardly penetrate the resist film 174 and the
polymer layers 176, and thus be ineffective. However, with this
embodiment, since the first processing liquid alters the condition
of the surface layers of the resist film 174 and the polymer layers
176 and cracks are formed therein prior to the supply of the second
processing liquid, the second processing liquid can easily
penetrate into these, this leading to effective utilization.
[0071] In addition, non-oxidized Cu particles are difficult to
dissolve and remove with the second processing liquid. However, as
the Cu particles 177 are oxidized by the first processing liquid,
they can be easily removed with the second processing liquid.
[0072] During the processing with the second processing liquid,
firstly, the second processing liquid is sprayed from the spray
nozzle 32 for several tens of seconds. At this time, by rotating
the rotor 5 at a low speed in the range of 1 to 500 rpm for the
first several tens of seconds, the second processing liquid is
spread over the surface of wafers W. In this case, the speed of
revolution of the rotor 5 can be used to control how evenly the
second processing liquid is spread, based on its viscosity, and the
resist film 174, the polymer layers 176 and the oxidized Cu
particles 177 can be uniformly dissolved. Uniform diffusion of the
second processing liquid becomes possible by, in the case that the
viscosity of the second processing liquid is high, having the rotor
5 spin at a higher speed within the aforementioned range, and if
viscosity is low, to have the rotor 5 spin at a lower speed within
the aforementioned range.
[0073] When the resist film 174, the polymer layers 176 and the Cu
particles 177 are dissolved, there exists a reacted second
processing liquid on the surfaces of the wafers W. As the
concentration of the active component in the processing liquid is
reduced, the reactivity of the processing liquid is lowered. In
such a case, the supply of the second processing liquid should be
stopped, and while heated N.sub.2 gas is sprayed from the spray
nozzle 32 for several seconds, the rotation speed of the rotor 5
should be increased to a high speed in the range of 100 to 3000
rpm, a higher rotation speed than the rotation speed at the time of
provision of the second process liquid. As a result of the pressure
provided by the inert gas and centrifugal force caused by the
revolution of the rotor 5, the reacted second process liquid can be
removed from the surfaces of wafers W. At this time, it is
preferable to control the rotation speed of the rotor 5 according
to the viscosity of the reacted second process liquid adhered on
the surfaces of the wafers W.
[0074] After the reacted processing liquid is removed from the
surfaces of the wafers W in the above fashion, the speed of the
rotor 5 is again reduced to a low speed in the range of 1 to 500
rpm, and the second processing liquid is sprayed from spray nozzle
32. By repeating the step of providing the second processing liquid
and low-speed rotation of wafers W, and the step of high-speed
rotation of the wafers W in order to remove the reacted second
processing liquid therefrom, for several times to several thousand
times, it is possible to provide a highly reactive new second
processing liquid to the surfaces of wafers W at all times, and
thus remove the resist film, the polymer layers and the Cu
particles efficiently.
[0075] After the removal process of the resist layer, the polymer
layers, and Cu adhesive particles is completed, IPA or pure water
is sprayed from the spray nozzle 32, rinsing from wafers W any
remaining reaction products.
[0076] The second processing liquid used in the processing is
discharged though the second drain port 64 to the drainpipe 65, and
collected in the recycle tank of the second processing liquid tank.
As needed, in the time between the completion of processing with a
second processing liquid and the start of processing with a first
processing liquid, a new second processing liquid is supplied to
the new liquid tank of the second processing liquid tank. Then, any
overflow from the new liquid tank is supplied to the recycle tank
of the second processing liquid tank.
[0077] While it is acceptable to complete the removal processes
after carrying out the aforementioned process with the first
processing liquid and the second processing liquid, it is
preferable to repeat the processes using the first and second
processing liquid several times. In other words, in some cases
conducting the processes with the first processing liquid and the
second processing liquid only one time each may be insufficient,
but repeating the processes leads to more effectiveness, and it is
possible to completely remove resist film, polymer layers and Cu
particles.
[0078] In this case, a rinse process may be carried out after the
process with the first processing liquid and before the process
with the second processing liquid. Such a rinse process may be
carried out by rotating the wafers W, as needed, and by feeding
pure water or IPA as a rinse solution to the wafers W while
positioning the inner cylinder 8a in the retracted position. After
pure water or IPA is supplied to the wafers W, a drying process may
be conducted by rotating rotor 5 at a high speed, thereby spinning
off the rinse liquid from the wafers W.
[0079] After this type of rinse process is carried out, a first
processing liquid is fed to the wafers W in the first process space
20. Immediately after supply of the first processing liquid has
begun, the rinse liquid remaining in the first process space 20 is
mixed with the first processing liquid, and the mixture is
discharged from the first process space 20. As the first processing
liquid is diluted by the rinse liquid, in the event that the
mixture is collected in the first processing liquid tank 101, it is
likely that the concentration of the active component of the first
processing liquid in the first processing liquid tank will be
reduced. Accordingly, in such a case, a new first processing liquid
is supplied to the first processing liquid in the first processing
liquid tank 101. However, when doing so, it is preferable to
control the amount of the discharged liquid (i.e., the mixture of
the first processing liquid and the rinse liquid) collected into
the tank and the amount of the new processing liquid added into the
tank, in order to maintain the process effectiveness by the first
processing liquid. Specifically, based on the amount of the new
processing liquid supplied to the recycle tank 103 of the first
liquid process tank 101, collection of the discharge liquid should
be controlled so that the concentration of the active component of
the first processing liquid in the recycle tank 103 becomes higher
than prescribed. In this case, is the collection of discharge
liquid would cause the processing ability of the first processing
liquid in the recycle tank 103 to fall below a desired level,
control should be set to have collection amount be zero, in other
words, the mixture of the first processing liquid and the rinse
liquid should not be collected.
[0080] After the processes with the first and second processing
liquids are completed, the inner cylinder 8a is moved from inner
side of the outer cylinder 7c to the outer side of the casing 6,
thereby positioning the wafers W in the process space 20 formed in
the outer cylinder 7c. In this state, the wafers W are rinsed by
pure water being sprayed from the spray nozzle 22, and lastly the
rotor 5 is rotated at a high speed, and spin-drying of the wafers W
is performed.
[0081] As mentioned above, through the utilization of differing
processing liquids, it is possible to completely remove the resist
film, the polymer layers and the Cu particles via wet cleaning,
with no dry ashing, and without causing any damage to underlying
low-k films.
[0082] With the example shown in FIG. 9, the via-hole is formed to
go through to the Cu wiring layer 171 of the underlying damascene
structure. However, in some cases, a via-hole 175 only penetrates
to stopper layer 172, as shown in FIG. 10. In this case, as the
via-etching does not reach the Cu wiring layer 171, Cu sputter is
not generated, and the only objects of removal by processing liquid
are the resist film 174 and the polymer layer 176. Of course, in
this instance as well, the resist film 174 and the polymer layer
176 can be dissolved and removed in the same manner as in the use
of aforementioned processing apparatus 1. Specifically, after the
first processing liquid alters the condition of the resist film 174
and the polymer layer 176, making it easy for liquid to permeate,
thus enhancing the dissolving and lift-off effect of the second
processing liquid, which removes them. During this process, as the
Cu wiring layer is not exposed, there is no need for processing
with either of the liquids to be done in an inert gas atmosphere,
thus it is possible for the process to be carried out in an
atmosphere of air.
[0083] The present invention is not limited to the embodiment
mentioned above, and various other varieties are possible.
[0084] For example, the first processing liquid and/or second
processing liquid need not be limited to the examples, if
displaying the above characteristics or effects.
[0085] Also, in the above embodiment, processes with the first
processing liquid and the second processing liquid are carried out
in two different process spaces 20 and 30, to avoid mixture of the
two liquids. However, an apparatus having only a single process
space is sufficient.
[0086] A processing apparatus having only a single process space,
for example, can be constructed by removing the inner cylinder 8a
shown in FIGS. 1 and 2. With such an apparatus having only a single
process space, since both processes with a first processing liquid
and second processing liquid take place in the same process space,
it would be necessary to implement a rinse process in the interval
between the two processes, and drain the mixture of the processing
liquid and the rinse liquid. However, the method of draining and
recycling of discharged liquids, the control of the concentration
of the active component of the processing liquid, the rinse
process, etc., can all be carried out in the same manner as
mentioned above with the apparatus as shown in FIGS. 1 and 2.
[0087] In the above embodiment, the supply mechanisms for first
processing liquid and the second processing liquid are constructed
so as to make recycling of both possible. However, a construction
making recycling of either liquid is also applicable.
[0088] At the time of supplying processing liquid, as long as the
flow of processing liquid is formed on the surface of the wafer,
the substrate to be processed, it is not absolutely necessary for
the wafer to be rotated as indicated in the above embodiment. In
addition, this process need not be limited to batch processing, as
described above, but may also take the form of single-wafer
processing. Further, metallic adhesive particles are not limited to
Cu, and foundation of the resist film or the polymer layer is not
limited to low-k film.
[0089] The object to be processed is not limited to semi-conductor
wafers, and the process may be applied to liquid crystal display
(LCD) substrates, or other substrates.
[0090] According to the present invention, as the first processing
liquid alters the surfaces of the resist film and the polymer layer
so as to allow the second processing liquid provided thereafter to
permeate, this greatly enhances the effectiveness of the second
processing liquid's ability to dissolve and lift off the resist
film, the polymer layer, thus these can all be completely
removed.
[0091] Further, even in the case where sputtered metals are adhered
to the substrate, only these sputtered metals are oxidized by the
first processing liquid. In addition, as the second processing
liquid is provided in a non-oxidizing atmosphere, necessary
metallic layers, such as Cu wiring layers are not oxidized.
Accordingly, only the sputtered metals are dissolved and lifted
off. Thus it is possible for the sputtered metals to be completely
removed along with the resist film and the polymer layers without
causing any damage to the metal layers.
* * * * *