U.S. patent application number 13/223555 was filed with the patent office on 2012-03-22 for apparatus and method of processing substrate.
Invention is credited to Hideaki Hirabayashi, Naoaki Sakurai.
Application Number | 20120067847 13/223555 |
Document ID | / |
Family ID | 45816795 |
Filed Date | 2012-03-22 |
United States Patent
Application |
20120067847 |
Kind Code |
A1 |
Sakurai; Naoaki ; et
al. |
March 22, 2012 |
APPARATUS AND METHOD OF PROCESSING SUBSTRATE
Abstract
According to one embodiment, an apparatus of processing a
substrate includes a treatment chamber, a holder, a feed device,
and a temperature control device. The holder is provided in the
treatment chamber and is configured to rotatably hold the
substrate. The feed device includes a nozzle configured to eject an
etching solution to a surface of the substrate held by the holder.
The temperature control device includes first and second devices,
and a controller. The first device is configured to heat and/or
cool an atmosphere inside the treatment chamber. The second device
is configured to heat and/or cool the etching solution. The
controller is configured to control operation of the first and
second devices such that a temperature of the atmosphere is higher
than that of the etching solution in the nozzle and that difference
between the temperature of the atmosphere and that of the etching
solution is maintained constant.
Inventors: |
Sakurai; Naoaki;
(Yokohama-shi, JP) ; Hirabayashi; Hideaki;
(Yokohama-shi, JP) |
Family ID: |
45816795 |
Appl. No.: |
13/223555 |
Filed: |
September 1, 2011 |
Current U.S.
Class: |
216/83 ;
156/345.15 |
Current CPC
Class: |
H01L 21/6708 20130101;
H01L 21/67109 20130101; H01L 21/67248 20130101; H01L 21/31111
20130101 |
Class at
Publication: |
216/83 ;
156/345.15 |
International
Class: |
C23F 1/00 20060101
C23F001/00; C23F 1/08 20060101 C23F001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 22, 2010 |
JP |
2010-212632 |
Claims
1. An apparatus of processing a substrate comprising first and
second surfaces, comprising: a treatment chamber; a holder provided
in the treatment chamber, the holder being configured to rotatably
hold the substrate; a first feed device comprising a first nozzle
configured to eject an etching solution to the first surface of the
substrate held by the holder; and a temperature control device
comprising a first device configured to heat and/or cool an
atmosphere inside the treatment chamber, a second device configured
to heat and/or cool the etching solution, and a controller
configured to control operation of the first and second devices
such that a temperature of the atmosphere is higher than a
temperature of the etching solution in the first nozzle and that
difference between the temperature of the atmosphere and the
temperature of the etching solution is maintained constant.
2. The apparatus according to claim 1, further comprising a
humidifier configured to humidify the atmosphere.
3. The apparatus according to claim 1, further comprising a second
feed device comprising a second nozzle configured to eject a rinse
solution to the first surface of the substrate held by the holder,
wherein the temperature control device further comprises a third
device configured to heat and/or cool the rinse solution, and the
controller is further configured to control operation of the third
device such that the temperature of the rinse solution in the
second nozzle is equal to or higher than the temperature of the
etching solution in the first nozzle.
4. The apparatus according to claim 1, further comprising a blower
configured to blow dry gas to the substrate held by the holder.
5. The apparatus according to claim 1, wherein the first feed
device further comprises a third nozzle configured to eject the
etching solution to the second surface of the substrate held by the
holder, and the controller is further configured to control
operation of the first and second devices such that the temperature
of the atmosphere is higher than the temperature of the etching
solution in the third nozzle and that difference between the
temperature of the atmosphere and the temperature of the etching
solution is maintained constant.
6. The apparatus according to claim 5, further comprising a second
feed device comprising a fourth nozzle configured to eject a rinse
solution to the second surface of the substrate held by the holder,
wherein the temperature control device further comprises a third
device configured to heat and/or cool the rinse solution, and the
controller is further configured to control operation of the third
device such that a temperature of the rinse solution in the fourth
nozzle is equal to or higher than the temperature of the etching
solution in the third nozzle.
7. The apparatus according to claim 1, wherein the first feed
device further comprises a tank configured to contain the etching
solution, and a conduit configured to guide the etching solution
inside the tank to the first nozzle, wherein the second device is
configured to heat and/or cool the etching solution inside the
tank.
8. An apparatus of processing a substrate comprising first and
second surfaces, comprising: a treatment chamber; a holder provided
in the treatment chamber, the holder being configured to rotatably
hold the substrate; a first feed device comprising a first nozzle
configured to eject an etching solution to the first surface of the
substrate held by the holder; and a temperature control device
comprising a shielding member placed such that the shielding member
is opposed to the first surface of the substrate and forms a space
having a layer shape between the first surface and the shielding
member, the shielding member comprising a first device configured
to heat and/or cool gas in the space, a second device configured to
heat and/or cool the etching solution, and a controller configured
to control operation of the first and second devices such that a
temperature of the gas is equal to or higher than a temperature of
the etching solution in the nozzle.
9. A method of processing a substrate comprising first and second
surfaces in a treatment chamber, comprising: at least partially
etching the first surface by supplying an etching solution to the
first surface with rotating the substrate; and controlling a
temperature of the etching solution and a temperature of an
atmosphere inside the treatment chamber such that the temperature
of the atmosphere is higher than the temperature of the etching
solution and that difference between the temperature of the etching
solution and the temperature of the atmosphere is maintained
constant.
10. The method according to claim 9, further comprising humidifying
the atmosphere during the etching.
11. The method according to claim 9, further comprising rinsing the
first surface of the substrate with a rinse solution after the
etching, wherein the rinsing is performed under condition that a
temperature of the rinse solution is equal to or higher than the
temperature of the etching solution.
12. The method according to claim 11, further comprising blowing
dry gas to the substrate after the rinsing.
13. The method according to claim 9, further comprising: supplying
the etching solution to the second surface during the etching; and
controlling the temperature of the etching solution and the
temperature of the atmosphere such that the temperature of the
atmosphere is higher than the temperature of the etching solution
supplied to the second surface and that difference between the
temperature of the atmosphere and the temperature of the etching
solution is maintained constant.
14. The method according to claim 13, further comprising rinsing
the second surface of the substrate with the rinse solution after
the etching, wherein the rinsing is performed under condition that
a temperature of the rinse solution is equal to or higher than the
temperature of the etching solution supplied to the second surface.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from prior Japanese Patent Application No. 2010-212632,
filed Sep. 22, 2010, the entire contents of which are incorporated
herein by reference.
FIELD
[0002] Embodiments described herein relate generally to an
apparatus and a method of processing a substrate such as a
semiconductor wafer or a glass substrate.
BACKGROUND
[0003] In an apparatus which performs wet etching on a substrate
such as a semiconductor wafer or a glass substrate, oxide films on
the substrate are removed by supplying the substrate with an
etching solution while rotating the substrate. After an etching
treatment, a rinsing treatment with pure water and drying are
performed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a schematic view showing an apparatus of
processing a substrate, according to the first embodiment;
[0005] FIG. 2 is a schematic view showing an apparatus of
processing a substrate, according to the second embodiment; and
[0006] FIG. 3 shows temperature distributions in radial directions
of a wafer where an atmospheric temperature inside a chamber is
maintained constant while a temperature of an etching solution is
changed.
DETAILED DESCRIPTION
[0007] In general, according to one embodiment, an apparatus of
processing a substrate including first and second surfaces includes
a treatment chamber, a holder, a first feed device, and a
temperature control device. The holder is provided in the treatment
chamber and is configured to rotatably hold the substrate. The
first feed device includes a first nozzle configured to eject an
etching solution to the first surface of the substrate held by the
holder. The temperature control device includes a first device, a
second device, and a controller. The first device is configured to
heat and/or cool an atmosphere inside the treatment chamber. The
second device is configured to heat and/or cool the etching
solution. The controller is configured to control operation of the
first and second devices such that a temperature of the atmosphere
is higher than a temperature of the etching solution in the first
nozzle and that difference between the temperature of the
atmosphere and the temperature of the etching solution is
maintained constant.
[0008] According to another embodiment, an apparatus of processing
a substrate including first and second surfaces includes a
treatment chamber, a holder, a first feed device, and a temperature
control device. The holder is provided in the treatment chamber and
is configured to rotatably hold the substrate. The first feed
device includes a first nozzle configured to eject an etching
solution to the first surface of the substrate held by the holder.
The temperature control device includes a shielding member, a
second device, and a controller. The shielding member is placed
such that the shielding member is opposed to the first surface of
the substrate and forms a space having a layer shape between the
first surface and the shielding member, and the shielding member
includes a first device configured to heat and/or cool gas in the
space. The second device is configured to heat and/or cool the
etching solution. The controller is configured to control operation
of the first and second devices such that a temperature of the gas
is equal to or higher than a temperature of the etching solution in
the nozzle.
[0009] According to further another embodiment, a method of
processing a substrate comprising first and second surfaces in a
treatment chamber includes at least partially etching the first
surface by supplying an etching solution to the first surface with
rotating the substrate; and controlling a temperature of the
etching solution and a temperature of an atmosphere inside the
treatment chamber such that the temperature of the atmosphere is
higher than the temperature of the etching solution and that
difference between the temperature of the etching solution and the
temperature of the atmosphere is maintained constant.
[0010] Various embodiments will be described hereinafter with
reference to the accompanying drawings.
First Embodiment
[0011] FIG. 1 is a schematic view showing an apparatus of
processing a substrate, according to the first embodiment.
[0012] The apparatus of processing shown in FIG. 1 includes a
treatment chamber 1. A cross section of the treatment chamber 1
which is perpendicular to a vertical direction has, for example, an
approximate rectangular shape.
[0013] At a bottom part inside the treatment chamber 1, for
example, a columnar block 2 is provided to be vertically movable.
The columnar block 2 is, for example, rotatable about an axis in
parallel with a height direction thereof by a motor not shown.
[0014] A cylindrical rotary shaft 3 is attached to the block 2.
Here, the rotary shaft 3 has a cylindrical shape and penetrates to
the columnar block 2 along the height direction thereof. The rotary
shaft 3 is used as a third nozzle and a fourth nozzle which are
explained below.
[0015] A vacuum chuck 4 is provided on a top face of the block 2.
The vacuum chuck 4 holds a substrate, for example, a semiconductor
wafer 36 by suction. Here, the top surface and a bottom surface of
the wafer 36 held by the vacuum chuck 4 are a first surface and a
second surface, respectively.
[0016] An inner cup 5 and an outer cup 6 each have a cylindrical
shape, an upper part of which is bent toward inside of the cup, and
they are provided and nested to stand on the bottom part of the
chamber 1 such that they encircle the block 2. A top end of the
outer cup 6 is positioned at a higher position than a top end of
the inner cup 5.
[0017] An annular space between the columnar block 2 and the inner
cup 5 functions as an area for collecting an etching solution
scattered from the wafer 36 rotating during etching. The etching
solution scattered to the annular space is recovered through a
recovery line 7 connected to the bottom part of the chamber 1. An
annular space between the inner cup 5 and the outer cup 6 functions
as a liquid receiver portion which receives a rinse solution
scattered from the wafer 36 rotating during a rinsing treatment.
The rinse solution scattered to the annular space is discharged
through a drain line 8 connected to the bottom part of the chamber
1.
[0018] To the chamber 1, a first device 9 is connected through a
High Efficiency Particulate Air (HEPA) filter 10 and a feed line
11. The chamber 1 and the first device 9 are connected to each
other through a return line 12.
[0019] The first device 9 includes a heater and/or a cooler and
heats and/or cools an atmosphere inside the chamber 1. The first
device 9 may further include a humidification function. The first
device 9 takes in a gas from the inside of the treatment chamber 1
through the return line 12, heats and/or cools the gas, and
arbitrarily humidifies the gas. Thereafter, the first device 9
returns the gas to the treatment chamber 1 through the feed line 11
and the filter 10. As the first device 9, an air conditioner, for
example, a water-cooling air conditioner capable of precisely
controlling a temperature can be used. The following explanation
will be made assuming that the first device 9 has a function which
heats and humidifies the gas.
[0020] A first temperature sensor 13 and a humidity sensor 14 are
provided inside the chamber 1. The first temperature sensor 13 and
the humidity sensor 14 are each connected to a controller 38. To
the controller 38, the first device 9 is further connected.
[0021] The first device 9, the first temperature sensor 13, and the
controller 38 perform temperature adjustment of the atmosphere
inside the chamber 1. Specifically, the sensor 13 detects an
atmospheric temperature inside the chamber 1, and outputs a
detection signal to the controller 38. The controller 38 controls
operation of the first device 9 based on output from the sensor 13.
For example, the controller 38 performs a feedback control, using
the output from the sensor. According to an example, the controller
38 controls operation of the first device 9 so as to minimize an
absolute value of difference between an actually measured
temperature obtained from the output of the sensor 13 and a preset
temperature.
[0022] The first device 9, the humidity sensor 14, and the
controller 38 perform humidity adjustment inside the chamber 1.
Specifically, the sensor 14 detects the humidity inside the chamber
1 and outputs a detection signal to the controller 38. The
controller 38 controls operation of the first device 9 based on
output from the sensor 14. For example, the controller 38 performs
a feedback control, using the output from the sensor 14. According
to an example, the controller 38 controls operation of the first
device 9 so as to minimize an absolute value of difference between
the actually measured humidity and preset humidity.
[0023] The apparatus of processing further include a first feed
device.
[0024] The first feed device includes a tank 16, a first nozzle 15,
a first conduit, and a pump 39.
[0025] The tank 16 contains an etching solution. For example, a
fluorinated acid- or hydrofluoric acid-based solution may be used
as the etching solution.
[0026] The first nozzle 15 is provided to be positioned above the
center of the wafer 36 held by the vacuum chuck 4. The first nozzle
15 ejects the etching solution to the first surface of the wafer
36. For example, the first nozzle 15 is movable along a radial
direction of the wafer 36.
[0027] The first conduit functions to connect liquid between the
tank and the first nozzle 15. Here, the first conduit is a first
feed line 17 which is provided between the tank 16 and the first
nozzle 15.
[0028] A pump 39 is provided on the first conduit. The pump 39
pumps the etching solution from the tank 16 and supplies the
solution to the nozzle 15 through the line 17.
[0029] The first feed device further includes a third nozzle 3, a
second conduit, and a pump 40.
[0030] The third nozzle is the rotary shaft 3, as is described
above. The third nozzle 3 ejects the etching solution to the second
surface of the wafer 36.
[0031] The second conduit functions to connect liquid between the
tank 16 and the nozzle 3. Here, the second conduit includes a
second feed line 18, a valve 20, and a main line 19. One end of the
second feed line 18 is connected to the tank 16, and the other end
is connected to one end of the main line 19 through the valve 20.
The other end of the main line 19 is connected to the bottom end of
the nozzle 3.
[0032] The pump 40 is provided on the second conduit. The pump 40
pumps the etching solution from the tank 16 and supplies the
solution to the nozzle 3 through the second feed line 18, the valve
20, and the main line 19.
[0033] The third nozzle, the second conduit and the pump 40 may be
omitted.
[0034] For example, under control by the controller 38, the first
feed device guides the etching solution from the tank 16 to the
first nozzle 15 through the line 17 by the pump 39 while moving the
first nozzle 15 along the radial direction of the wafer 36, and the
etching solution is ejected to the first surface of the wafer 36
from the nozzle 15. At this time, the first feed device guides the
etching solution from the tank 16 to the nozzle 3 through the line
18, the valve 20, and the line 19 by the pump 40, and the etching
solution is ejected to the second surface of the wafer 36 from the
nozzle 3.
[0035] To the tank 16 of the first feed device, a second device 21
is connected through circulation lines 22 and 23. The second device
21 includes a pump, and it takes in the etching solution from the
tank 16 through the line 22 and returns the solution to the tank 16
through the line 23.
[0036] The second device 21 further includes a heater and/or a
cooler, and heats and/or cools the etching solution which has been
taken in. As the heater and/or the cooler, for example, an
air-cooling and water-cooling temperature regulator using a peltier
element and circulation fluid can be used. The second device 21 may
not heat or cool the etching solution inside the tank 16. For
example, the second device 21 may be configured to heat and/or cool
the etching solution inside the line 18 or 19, or the nozzle 3.
[0037] In the tank 16, a second temperature sensor 24 is provided.
The second temperature sensor 24 is connected to the controller 38.
To the controller 38, the second device 21 is further
connected.
[0038] The second device 21, the second temperature sensor 24, and
the controller 38 perform temperature adjustment of the etching
solution in the tank 16. Specifically, the sensor 24 detects a
temperature of the etching solution in the tank 16 and outputs a
detection signal to the controller 38. The controller 38 controls
operation of the second device 21 based on output from the sensor
24. For example, the controller 38 performs a feedback control,
using output from the sensor 24. According to one example, the
controller 38 controls operation of the second device 21 so as to
minimize an absolute value of difference between an actually
measured temperature obtained from the output of the sensor 24 and
a preset temperature.
[0039] The apparatus of processing further includes a second feed
device.
[0040] The second feed device includes a tank 26, a second nozzle
25, a third conduit, and a pump 41.
[0041] The tank 26 contains the rinse solution. For example, the
rinse solution is pure water.
[0042] The second nozzle 25 is provided to be positioned above the
center of the wafer held by the vacuum chuck 4 inside the treatment
chamber 1. The second nozzle 25 ejects the rinse solution to the
first surface of the wafer 36. The second nozzle 25 is movable
along a radial direction of the wafer 36.
[0043] The third conduit functions to connect liquid between the
tank 26 and the second nozzle 25. Here, the third conduit is a
third feed line 27 which is provided between the tank 26 and the
second nozzle 25.
[0044] The pump 41 is provided on the third conduit. The pump 41
pumps the rinse solution from the tank 26 and supplies the solution
to the nozzle 25 through the line 27.
[0045] The second feed device further includes a fourth nozzle, a
fourth conduit, and a pump 42.
[0046] The fourth nozzle is the rotary shaft 3, as is described
above. The fourth nozzle 4 ejects the rinse solution to the second
surface of the wafer 36.
[0047] The fourth conduit functions to connect liquid between the
tank 26 and the nozzle 3. The fourth conduit includes a fourth feed
line 28, a valve 29, and the main line 19. One end of the fourth
feed line 28 is connected to the tank 26, and the other end is
connected to one end of the main line 19 through the valve 29. The
other end of the main line 19 is connected to the bottom end of the
nozzle 3.
[0048] A pump 42 is provided on the fourth conduit. The pump 42
pumps the etching solution from the tank 26 and supplies the
solution to the nozzle 3 through the fourth feed line 28, the valve
29, and the main line 19.
[0049] The fourth nozzle, the fourth conduit, and the pump 42 may
be omitted.
[0050] For example, under control by the controller 38, the second
feed device guides the rinse solution from the tank 26 to the
nozzle 25 through the line 27 by the pump 41 while moving the
second nozzle 25 along the radial direction of the wafer 36, and
the rinse solution is ejected to the first surface of the wafer 36
from the nozzle 25. At this time, the second feed device guides the
rinse solution from the tank 26 to the nozzle 3 through the line
28, the valve 29, and the line 19 by the pump 42, and the etching
solution is ejected to the second surface of the wafer 36 from the
nozzle 3.
[0051] To the tank 26 of the second feed device, a third device 30
is connected through circulation lines 31 and 32. The third device
30 includes a pump, and it takes in the rinse solution from the
tank 26 through the line 32 and returns the solution to the tank 26
through the line 31.
[0052] The third device 30 further includes a heater and/or a
cooler, and heats and/or cools the rinse solution which has been
taken in. As the heater and/or the cooler, for example, an
air-cooling and water-cooling temperature regulator using a peltier
element and circulation fluid can be used. The third device 30 may
not heat or cool the rinse solution inside the tank 26. For
example, the third device 30 may be configured to heat and/or cool
the rinse solution inside the line 28 or 19, or the nozzle 3.
[0053] Inside the tank 26, a third temperature sensor 33 is
provided. The third temperature sensor 33 is connected to the
controller 38. To the controller 38, the third device 30 is further
connected.
[0054] The third device 30, the third temperature sensor 33, and
the controller 38 perform temperature adjustment of the rinse
solution in the tank 26. Specifically, the sensor 33 detects a
temperature of the rinse solution in the tank 26 and outputs a
detection signal to the controller 38. The controller 38 controls
operation of the third device 30 based on output from the sensor
33. For example, the controller 38 performs a feedback control,
using output from the sensor 33. According to an example, the
controller 38 controls operation of the third device 30 so as to
minimize an absolute value of difference between an actually
measured temperature obtained from the output of the sensor 33 and
a preset temperature.
[0055] The apparatus of processing further includes a blower 44.
The blower 44 includes a nozzle 34, a line 35, and a blower main
body 43. The nozzle 34 is positioned above the wafer 36 held by the
vacuum chuck 4 inside the treatment chamber 1 such that it blows
dry gas such as dry nitrogen to the wafer 36 from an upper tilted
direction. The line 35 is provided between the nozzle 34 and the
blower main body 43 provided outside the chamber 1 and connects
them, and it guides the dry gas from the blower main body 43 to the
nozzle 34.
[0056] Next, a method of processing a substrate, for example a
semiconductor wafer 36, according to the first embodiment, will be
described referring to the processing apparatus as described
above.
[0057] At first, a substrate such as a semiconductor wafer 36 is
held by the vacuum chuck 4. Typically, the atmosphere of the
chamber is substituted by inert gas such as nitrogen gas in
advance.
[0058] Subsequently, under control by the controller 38 the first
device 9 and the second device 21 are operated to adjust a
temperature of the gas inside the treatment chamber 1 and a
temperature of the etching solution. Specifically, the temperatures
are controlled such that the atmospheric temperature inside the
treatment chamber 1 is higher than the temperature of the etching
solution and difference between these temperatures is maintained
constant. For example, when the temperature of the etching solution
is set within the range of 22 to 24.degree. C., the target
temperature of the atmosphere inside the chamber 1 is set to be 1.5
to 8.degree. C. higher than the temperature of the etching
solution. When the temperature of the etching solution is set to be
higher, for example, at 25.degree. C. or more, preferably within a
range of 27 to 35.degree. C., the target temperature of the
atmosphere inside the chamber 1 is set to be 1 to 15.degree. C.
higher than that of the etching solution. If difference between the
atmospheric temperature inside the chamber 1 and the temperature of
the etching solution is small, it is difficult to improve the
in-plane uniformity of etching of the wafer.
[0059] Preferably, in addition to the temperature adjustment
described above, the humidity of the atmosphere inside the chamber
1 is controlled by the controller 38 and the first device 9. For
example, control is performed such that the relative humidity of
the atmosphere inside the chamber 1 so as to be within a range of
90 to 100%.
[0060] Next, the vacuum chuck 4 holding the wafer 36 is rotated,
and then the etching solution is ejected from the first nozzle 15
to the wafer 36 with moving the first nozzle 15 along the radial
direction of the wafer 36 to treat the surface of the wafer 36. For
example, oxide film is removed from the surface of the wafer
36.
[0061] The etching solution on the wafer 36 is outwardly
transferred from the center of the wafer 36 due to centrifugal
force, and then scatters along the radial direction of the wafer
36. At this time, if the height of the block 2 is controlled such
that the top surface of the wafer 36 is lower than the height of
the top end of the inner cup 5, the scattered etching solution is
collected in the annular space between the columnar block 2 and the
inner cup 5 and is recovered through a recovery line 7 which is
connected to the bottom part of the chamber 1.
[0062] In this method, temperature reduction of the wafer 36 or the
etching solution thereon caused by vaporization of the etching
solution is small, since the atmospheric temperature inside the
chamber 1 is controlled to be higher than the temperature of the
etching solution. Therefore, breadth of temperature distribution
occurring due to the evaporation of the etching solution on the
surface of the wafer 36, that is, temperature difference between
the center of the wafer 36 and the periphery thereof is minimized,
and thereby the in-plane uniformity of the etching of the wafer 36
can be improved.
[0063] In particular, when an etching speed is increased by using a
heated etching solution, the breadth of temperature distribution
caused by the vaporization of the etching solution on the surface
of the wafer 36 becomes broad compared to a case of using the
etching solution at a room temperature. According to the
above-mentioned method, even in the case of using the heated
etching solution, the breadth of temperature distribution can be
sufficiently diminished, and the in-plane uniformity of the wafer
36 can be improved.
[0064] According to this method, as is described above, the
atmosphere inside the chamber 1 is preferably humidified. When the
atmospheric temperature inside the chamber 1 is increased,
vaporization of the etching solution on the surface of the wafer 36
is accelerated. When the humidity inside the chamber 1 is
increased, the vaporization of the etching solution can be
restrained, and thus the breadth of the temperature distribution
caused by the vaporization of the etching solution on the surface
of the wafer 36 can be diminished.
[0065] When a solvent contained in the etching solution, for
example, water is vaporized on the surface of the wafer 36, a
concentration of the etching solution is increased. If the breadth
of concentration distribution is broad, ununiformity of etching
occurs due to the breadth. Excess increase of the concentration of
the etching solution can be prevented by humidifying the atmosphere
inside the chamber 1.
[0066] Therefore, if the atmosphere inside the chamber 1 is
humidified, etching can be achieved with better uniformity compared
to a case where the atmosphere is not humidified.
[0067] While the first surface of the wafer 36 is subjected to
etching, the etching solution can be supplied to the second surface
of the wafer 36 as well. Namely, the pump 40 may be operated in
condition that a valve 29 is closed and a valve 20 is open.
Thereby, the etching solution is pumped from the tank 16 and is
supplied to the nozzle 3 through the line 18, the valve 20, and the
line 19, and is ejected to the second surface of the wafer from the
nozzle 3.
[0068] If the etching solution is not supplied to the second
surface of the wafer 36, the etching solution supplied to the first
surface of the wafer flows to a periphery portion of the second
surface of the wafer 36, and etching may occur in the periphery
portion. In this case, the periphery portion of the wafer 36
becomes thinner than the central portion of the wafer.
[0069] If the etching solution is supplied to the second surface of
the wafer 36 while the first surface of the wafer 36 is subjected
to etching, occurrence of the thickness ununiformity of the wafer
36 can be avoided. Here, difference between the atmospheric
temperature inside the chamber 1 and the temperature of the etching
solution supplied to the second surface of the wafer 36 is within
the range described above and is maintained constant, since the
temperature of the etching solution in the tank 16 is controlled as
is described above. Therefore, the ununiformity of thickness due to
the supply of the etching solution to the second surface cannot
occur.
[0070] Subsequently, supply of the etching solution to the wafer 36
is stopped. The top surface of the wafer 36 held by the vacuum
chuck 4 is then positioned to be higher than the top end of the
inner cup 5 and lower than the top end of the outer cup 6 by moving
the block 2 upwardly. While the wafer 36 is kept rotated, the pump
41 is operated to supply the etching solution, for example, pure
water from the tank 26 to the second nozzle 25 through the first
feed line 27 and eject it to the wafer 36 from the nozzle 25.
Thereby, the etching solution on the wafer 36 is rinsed out.
[0071] The rinse solution on the wafer 36 is outwardly transferred
from the center of the wafer 36 due to centrifugal force, and then
scatters along the radial direction of the wafer 36. The scattered
rinse solution is collected in the annular space between the inner
cup 5 and the outer cup 6, and can be recovered through the drain
line 8 which is connected to the bottom part of the chamber 1.
[0072] In this rinsing treatment, the temperature of the rinse
solution inside the tank 26 is controlled, for example, to be equal
to or higher than the temperature of the etching solution. In the
rinsing treatment performed subsequent to the etching treatment,
residual etching solution may etch the surface of the wafer 36.
[0073] If the rinse solution having a lower temperature than that
of the etching solution is supplied to the wafer, the etching
solution is cooled by the rinse solution. However, the cooling of
the etching solution does not occur uniformly within the surface of
the wafer 36. The etching speed is varied in accordance with the
temperature of the etching solution. Therefore, the wafer 36 cannot
be etched uniformly, and the thickness of the wafer 36 may become
ununiform. As is described above, in this method, the temperature
of the rinse solution is controlled to be equal to or higher than
that of the etching solution. Therefore, the ununiform cooling of
the residual etching solution on the wafer 36 and ununiformity of
the etching speed caused thereby can be avoided, and thus
occurrence of the thickness ununiformity of the wafer 36 can be
also avoided.
[0074] When the etching solution is supplied to the second surface
of the wafer 36 as well, the rinse solution may be also supplied to
the second surface of the wafer 36 in the rinsing treatment of the
wafer 36. Namely, in condition that a valve 20 is closed and a
valve 29 is open, the pump 42 may be operated to pump the rinse
solution, for example, pure water from the tank 26 and supply to
the nozzle 3 through the line 28, the valve 29, and the line 19, to
eject it to the second surface of the wafer from the nozzle 3.
Thereby, the etching solution on the second surface of the wafer 36
is rinsed out.
[0075] Difference between the temperature of the etching solution
supplied to the second surface of the wafer 36 and that of the
rinse solution is, for example, within the range described above
and is maintained constant. In this case, occurrence of etching
ununiformity due to the residual etching solution can be avoided,
and thus thickness ununiformity of the wafer 36 cannot occur.
[0076] Subsequently, supply of the rinse solution is stopped. Then,
while the wafer 36 is maintained, dry gas is supplied to the nozzle
34 from the blower main body 43 through the line 35 and is blown to
the wafer 36 from the nozzle 34. Thereby the wafer 36 is dried.
Here, the dry gas is, for example, dry nitrogen.
[0077] By thus blowing dry gas to the wafer 36, the humidity near
the wafer 36 can be decreased, and the drying time can be
shortened.
[0078] According to the first embodiment as described above, in the
etching of the substrate, the etching speed can be accelerated and
simultaneously in-plane uniformity occurring between the center of
the substrate and the periphery thereof can be avoided.
Second Embodiment
[0079] FIG. 2 is a schematic view showing an apparatus of
processing a substrate, according to the second embodiment. Members
shown in FIG. 2, which are common to FIG. 1, will be respectively
denoted by common reference symbols, and descriptions thereof will
be omitted herefrom.
[0080] In the apparatus of processing a substrate shown in FIG. 2,
a shielding member 37 is provided to be opposed to the wafer 36 and
to be vertically movable. The shielding member 37 forms a space
having a layer shape between the shielding member 37 and the first
surface of the wafer 36. The shielding member 37 prevents a
temperature of the gas filling up the space from decreasing and/or
increasing due to an atmospheric temperature of other space inside
the chamber 1.
[0081] The shielding member 37 includes a plate 45 and a first
device 9.
[0082] For example, the plate 45 has an approximate same size as
that of the wafer 36. According to an example, the plate 45 has,
for example, a disc shape with a thickness of 5 to 10 mm, and is
made of polytetrafluoroethylene.
[0083] The first device 9 heats and/or cools the gas in the space
between the shielding member 37 and the wafer 36. The first device
9 is, for example, a heater. The first device 9 may be, for
example, provided to be adjacent to the plate 45, or may be built
in the plate 45. Here, the first device 9 is assumed to be a heater
Which is built in the plat body 45.
[0084] The shielding member 37 is provided with two through holes.
The inner walls of the through holes each are provided with an
insulating material having a ring form. The nozzle 15 and 25
penetrate the shielding member 37 through the through holes.
[0085] The first temperature sensor not shown is connected to the
controller 38. In this embodiment, the first temperature sensor is,
for example, held by the shielding member 37, and it detects a
temperature of the space formed between the shielding member 37 and
the wafer 36 and having a layer shape and outputs a detection
signal to the controller 38. For example, the first temperature
sensor may be provided on a surface of the shielding member opposed
to the wafer 36, on a back surface of the aforementioned surface,
or the like, to detect a temperature of the shielding member 37
itself and output the detection signal to the controller 38.
[0086] The heater 9, the first temperature sensor, and the
controller 38 perform temperature adjustment of the gas in the
space formed between the shielding member 37 and the wafer 36 and
having a layer shape. Specifically, the temperature sensor detects
the temperature of the space formed between the shielding member 37
and the wafer 36 and outputs a detection signal to the controller
38. The controller 38 controls the operation of the heater 9 based
on the outputs from the temperature sensor. For example, the
controller 38 performs feedback control using the outputs from the
first temperature sensor. According to an example, the controller
38 controls operation of the heater 9 so as to minimize an absolute
value of difference between an actually measured temperature
obtained from the output of the first temperature sensor and a
preset temperature of the heater 9.
[0087] The nozzle 34 can be moved vertically and horizontally in
the treatment chamber 1. Thus, when the wafer 36 is dried, dry gas
can be blown to the substrate by moving the shielding member 37
upwardly and then positioning the nozzle 34 between the wafer 36
and the shielding member 37.
[0088] Described next is a method of processing a substrate by
using the processing apparatus as described above, according to the
second embodiment.
[0089] The method according to the second embodiment is the same as
the method according to the first embodiment, except that the
breadth of the temperature of the etching solution on the wafer 36,
that is, the temperature difference between the center of the wafer
36 and the periphery thereof is minimized with use of the shielding
member 37. The temperature of the space formed between the
shielding member 37 and the wafer 36 and having a layer shape is
controlled to be equal to or higher than that of the etching
solution. The reason why the temperature of the space may be equal
to that of the etching solution is that more precise temperature
adjustment is achieved since the first device 9 adjusts a
temperature of a smaller space compared to the first
embodiment.
[0090] The temperature adjustment is performed as described above,
and thus temperature reduction of the wafer 36 or the etching
solution thereon due to the vaporization of the etching solution is
smaller. Therefore, the breadth of the temperature distribution
caused by the vaporization of the etching solution on the surface
of the wafer 36, that is, temperature difference between the center
of the substrate and the periphery thereof is minimized. Thus, the
in-plane uniformity in the surface of the wafer 36 can be
improved.
[0091] According to the second embodiment as described above, the
etching speed can be accelerated in the etching of the substrate,
and simultaneously the thickness ununiformity occurring between the
center of the substrate and the periphery thereof can be
avoided.
[0092] Although a semiconductor wafer is used as a substrate in
each of the first and second embodiments, other substrates such as
a glass substrate may be used.
[0093] Hereinafter, more concrete examples will now be described
referring to the processing apparatuses described above.
Examples 1 to 3
[0094] In the processing apparatus as shown in FIG. 1, breadth of
temperature distribution caused by supplying a liquid to the
substrate was studied.
[0095] The wafer 36 having a radius of 150 nm was held by the
vacuum chuck 4. As the wafer 36, a wafer with temperature detection
chips buried along the radial direction was used. Then, while
rotating the wafer 36, pure water was ejected from the first nozzle
15 to the wafer 36, and temperature was measured by the temperature
detection chips from the center of the wafer 36 to the periphery
thereof. Conditions for measurement are indicted below.
[0096] Rotation speed of wafer 36: 500 rpm
[0097] Ejection amount of pure water: 1.5 to 2.0 L/min
[0098] Atmospheric temperature inside chamber 1: 24.1.degree.
C.
[0099] Temperature of pure water: 22.5.degree. C., 24.5.degree. C.,
and 26.5.degree. C.
[0100] Ejection period of pure water per wafer: 20 seconds
[0101] Results are shown in FIG. 3. In FIG. 3, curves of Example 1,
2, and 3 show temperature distribution when a temperature of pure
water was controlled at 22.5.degree. C., 24.5.degree. C., and
26.5.degree. C., respectively. As is apparent from FIG. 3, in
Example 1 in which the atmospheric temperature in the chamber 1 was
set to be higher than the temperature of pure water, in-plane
temperature uniformity of the wafer was improved compared to
Examples 2 and 3 in which the atmospheric temperature inside the
chamber 1 is lower than that of pure water.
[0102] Next, uniformity of etching was studied. The same treatment
described above was performed except that an etching solution and a
wafer having thermally oxidized film were used in place of pure
water and the wafer with the buried temperature detection chips.
The etching solution used herein is an aqueous solution containing
3 wt % of ammonium hydrogen fluoride, 34 wt % of aluminum fluoride
solution, and maximum 1 wt % of a surfactant, and pure water.
[0103] The uniformity of etching was obtained by carrying out the
measurement described below before and after the aforementioned
treatment.
[0104] First, thickness of the thermally oxidized film of a wafer
not being subjected to etching was measured with respect to four
diameter directions with use of an optical interferotype
spectroscopic ellipsometer. Next, relationship between distance
from the center of the wafer and thickness of the thermally
oxidized film was obtained by averaging the data obtained thereby.
Subsequently, the wafer was subjected to etching treatment and,
after 20 seconds from beginning of the etching, the same
measurement as described above was carried out. Then, for each
distance from the center of the wafer, difference between thickness
of the thermally oxidized film before etching and that of the film
after etching was calculated as an etching amount. The procedure
mentioned above was repeated four times, and the average of the
data obtained thereby was calculated. From the data, a maximum
etching amount, a minimum etching amount, and an average etching
amount were obtained, and difference between the maximum etching
amount and the minimum etching amount was divided by the average
etching amount. The value obtained thereby was etching uniformity.
The results are shown in Table 1.
TABLE-US-00001 TABLE 1 Atmospheric Temperature temperature of
etching Etching In-plane inside solution amount etching chamber
(.degree. C.) (.degree. C.) (nm) uniformity (%) Example 1 24.1 22.5
4.37 1.27 Example 2 24.1 24.5 4.97 1.63 Example 3 24.1 26.5 5.61
2.37
[0105] As is apparent from Table 1, in Example 1 in which the
atmospheric temperature inside the chamber 1 was higher than the
temperature of the etching solution, in-plane etching uniformity of
the wafer was improved compared with Examples 2 and 3 in which the
atmospheric temperature inside the chamber 1 was lower than the
temperature of the etching solution.
[0106] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. Indeed, the novel
embodiments described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
* * * * *