U.S. patent application number 13/551133 was filed with the patent office on 2012-11-08 for annealing apparatus.
This patent application is currently assigned to TOKYO ELECTRON LIMITED. Invention is credited to Shigeru KASAI, Hiroyuki MIYASHITA, Masamichi NOMURA, Miwa SHIMIZU, Tomohiro SUZUKI, Sumi TANAKA, Masatake YONEDA.
Application Number | 20120279944 13/551133 |
Document ID | / |
Family ID | 39845645 |
Filed Date | 2012-11-08 |
United States Patent
Application |
20120279944 |
Kind Code |
A1 |
KASAI; Shigeru ; et
al. |
November 8, 2012 |
ANNEALING APPARATUS
Abstract
Provided is an annealing apparatus, which is free from a problem
of reduced light energy efficiency resulted by the reduction of
light emission amount due to a heat generation and capable of
maintaining stable performance. The apparatus includes: a
processing chamber 1 for accommodating a wafer W; heating sources
17a and 17b including LEDs 33 and facing the surface of the wafer W
to irradiate light on the wafer W; light-transmitting members 18a
and 18b arranged in alignment with the heating sources 17a and 17b
to transmit the light emitted from the LEDs 33; cooling members 4a
and 4b supporting the light-transmitting members 18a and 18b at
opposite side to the processing chamber 1 to make direct contact
with the heating sources 17a and 17b and made of a material of high
thermal conductivity; and a cooling mechanism for cooling the
cooling members 4a and 4b with a coolant.
Inventors: |
KASAI; Shigeru; (Nirasaki
shi, JP) ; MIYASHITA; Hiroyuki; (Nirasaki-shi,
JP) ; YONEDA; Masatake; (Nirasaki-shi, JP) ;
SUZUKI; Tomohiro; (Nirasaki-shi, JP) ; TANAKA;
Sumi; (Nirasaki-shi, JP) ; NOMURA; Masamichi;
(Nirasaki-shi, JP) ; SHIMIZU; Miwa; (Nirasaki-shi,
JP) |
Assignee: |
TOKYO ELECTRON LIMITED
Minato-ku
JP
|
Family ID: |
39845645 |
Appl. No.: |
13/551133 |
Filed: |
July 17, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12440034 |
Mar 5, 2009 |
8246900 |
|
|
PCT/JP07/67053 |
Aug 31, 2007 |
|
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13551133 |
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Current U.S.
Class: |
219/50 |
Current CPC
Class: |
Y02P 70/521 20151101;
H01L 21/67109 20130101; H01L 21/67115 20130101; Y02E 10/50
20130101; Y02P 70/50 20151101; H01L 31/1864 20130101 |
Class at
Publication: |
219/50 |
International
Class: |
H05B 1/00 20060101
H05B001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2006 |
JP |
2006-240420 |
Feb 15, 2007 |
JP |
2007-034417 |
Mar 27, 2007 |
JP |
2007-081609 |
Claims
1. An annealing apparatus comprising: a processing chamber for
accommodating an object to be processed; a heating source including
a plurality of light emitting devices and provided to face at least
one surface of the object to irradiate light on the object; a
light-transmitting member arranged in alignment with the heating
source to transmit the light emitted from the light emitting
devices; a support member for supporting the heating source; a
power supply mechanism provided at a rear surface side of the
support member for supplying a power to the light emitting devices
via the support member; a gas exhaust mechanism for exhausting an
inside of the processing chamber; and a processing gas supply
mechanism for supplying a processing gas into the processing
chamber.
2. The annealing apparatus of claim 1, wherein the heating source
comprises a plurality of light emitting device arrays each
including: a support body provided at the support member; a
plurality of electrodes formed on the support body; a plurality of
light emitting devices formed on the electrodes; and a power supply
electrode for supplying a power to the light emitting devices, and
wherein the power supply mechanism has a plurality of electrode
rods connected to the power supply electrode of each of the light
emitting device arrays and extending through the support member and
a plurality of power supply members through which to supply a power
to the electrode rods.
3. The annealing apparatus of claim 2, wherein the electrode rods
and the power supply members are brought into contact with each
other by spring-biased pins.
4. The annealing apparatus of claim 2, wherein the light emitting
devices are divided to be arranged in each of power supply areas,
wherein the power supply area includes a plurality of the power
supply electrodes in a corresponding relationship therewith, and
wherein the power supply electrodes are arranged along a straight
line.
5. The annealing apparatus of claim 4, wherein the power supply
electrodes include a plurality of negative electrodes and a common
positive electrode.
6. The annealing apparatus of claim 4, wherein the light emitting
devices are provided in the power supply areas in a form of a
parallel connection of a plurality of sets of serially connected
light emitting devices.
7. The annealing apparatus of claim 1, wherein the light emitting
devices are light-emitting diodes.
8. The annealing apparatus of claim 2, wherein the light emitting
devices are light-emitting diodes.
9. The annealing apparatus of claim 3, wherein the light emitting
devices are light-emitting diodes.
10. The annealing apparatus of claim 4, wherein the light emitting
devices are light-emitting diodes.
11. The annealing apparatus of claim 5, wherein the light emitting
devices are light-emitting diodes.
12. The annealing apparatus of claim 6, wherein the light emitting
devices are light-emitting diodes.
Description
CROSS-REFERENCE(S) TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 12/440,034, filed on Mar. 5, 2009, the entire content of which
is incorporated herein by reference. U.S. application Ser. No.
12/440,034 is a National Stage Entry of PCT/JP2007/067053, filed on
Aug. 31, 2007, and claims priority to Japanese Patent Application
No. 2006-240420, filed on Sep. 5, 2006; Japanese Patent Application
No. 2007-034417, filed on Feb. 15, 2007; and Japanese Patent
Application No. 2007-081609, filed on Mar. 27, 2007.
FIELD OF THE INVENTION
[0002] The present invention relates to an annealing apparatus for
annealing a semiconductor wafer and the like by irradiating thereto
lights emitted from light emitting devices such as LEDs or the
like.
BACKGROUND OF THE INVENTION
[0003] In a manufacturing process of a semiconductor device, a
semiconductor wafer (hereinafter simply referred to as "wafer") as
a substrate to be processed is subjected to film formation,
oxidative diffusion, modification and various kinds of heat
treatments such as annealing and the like. To meet high-speed and
high-integration requirements in the semiconductor devices, the
annealing performed after ion implantation requires high-speed
heating and cooling for the purpose of minimizing diffusion. As an
annealing apparatus capable of performing the high-speed heating
and cooling, there has been proposed an annealing apparatus that
employs LEDs (Light-Emitting Diodes) as a heating source (see,
e.g., Patent Document 1).
[0004] In case the LEDs are used as a heating source of the
annealing apparatus, there is a need to generate a great light
energy in keeping with the rapid heating. This makes it necessary
to mount the LEDs in high density.
[0005] However, it is known that heat (heat generation) reduces the
light emission amount of the LEDs. Therefore, if the influence of
the heat generated in the LEDs (i.e., the influence of the input
energy not converted to light) grows heavier by the high-density
mounting of the LEDs, it is difficult to obtain an enough light
emission amount from the LEDs. Thus far, no way is known to
effectively cool the LEDs and to allow them to make a stable
performance.
[0006] In addition, the annealing apparatus described above employs
a multiplicity of LEDs and therefore has a complicated power supply
mechanism. Thus, there is a need for a simple and easy-to-use power
supply mechanism.
SUMMARY OF THE INVENTION
[0007] In view of the above, it is an object of the present
invention to provide an annealing apparatus using light emitting
devices such as LEDs or the like as a heating source, which is free
from a problem of reduced light energy efficiency resulted by the
reduction of light emission amount due to a heat generation and
which is capable of maintaining stable performance.
[0008] Another object of the present invention is to provide an
annealing apparatus capable of supplying a power to light emitting
devices in a simple and easy manner.
[0009] In accordance with a first aspect of the present invention,
there is provided an annealing apparatus including: a processing
chamber for accommodating an object to be processed; a heating
source including a plurality of light emitting devices and provided
to face at least one surface of the object to irradiate light on
the object; a light-transmitting member arranged in alignment with
the heating source to transmit the light emitted from the light
emitting devices; a cooling member supporting the
light-transmitting member at opposite side to the processing
chamber to make direct contact with the heating source and made of
a material of high thermal conductivity; a cooling mechanism for
cooling the cooling member with a coolant; a gas exhaust mechanism
for exhausting an inside of the processing chamber; and a
processing gas supply mechanism for supplying a processing gas into
the processing chamber.
[0010] In accordance with the first aspect, the heating source may
have a plurality of light emitting device arrays each including a
support body provided with a rear surface making surface-to-surface
contact with the cooling member and made of a material of high
thermal conductivity, a plurality of electrodes arranged to make
surface-to-surface contact with the support body and a plurality of
light emitting devices arranged to make surface-to-surface contact
with the electrodes. In this case, the cooling member is preferably
made of copper and the support body is made of AlN.
[0011] Further, a space may be defined between the cooling member
and the light-transmitting member, the heating source being
provided in the space. Furthermore, transparent resin may be filled
in the space. The transparent resin may includes a relatively hard
resin provided in a portion including the light emitting devices at
the side of the cooling member and a relatively soft resin provided
at the side of the light-transmitting member.
[0012] Further, an inert gas may be filled in the space. Besides,
the annealing apparatus may further includes an exhaust mechanism
for exhausting the space to vacuum and an inert gas supply
mechanism for supplying the insert gas into the space.
[0013] Further, in the configuration having the light emitting
device arrays, a space may be defined between the cooling member
and the light-transmitting member, wherein a liquid, which has a
refractive index falling between refractive indices of the light
emitting devices and the light-transmitting member, is filled in
the space and wherein the support body is screw-fixed to the
cooling member through a heat transfer layer. In this case, the
support body may include an external frame arranged to make contact
with the cooling member, the external frame having an inner
reflection surface and a liquid through hole.
[0014] Further, in accordance with the first aspect, the heating
source includes a plurality of light emitting device arrays. Each
of the light emitting device array is formed of a unit having: a
support body provided to support a plurality of light emitting
devices and made of a material of high thermal conductivity; a
thermal diffusion member soldered or brazed to a rear surface of
the support body and made of a material of high thermal
conductivity; a resin layer provided to cover the light emitting
devices supported by the support body and made of transparent
resin; and a power supply electrode passing through the thermal
diffusion member and the support body to supply a power to the
light emitting devices, the light emitting device arrays being
screw-fixed to the cooling member via paste of high thermal
conductivity. In this case, the cooling member and the thermal
diffusion member preferably made of copper and the support body is
made of AlN.
[0015] Further, a space may be defined between the resin layer and
the light-transmitting member, and the apparatus may further
include an exhaust mechanism for exhausting the space to vacuum.
The exhaust mechanism may include an exhaust path communicating
with the space, a buffer member provided in the exhaust path and a
pump for exhausting the space to vacuum via the exhaust path and
the buffer member.
[0016] The cooling member may include a plurality of attachment
members to which the light emitting device arrays are attached,
each of the attachment members having a frame member as a spacer
provided to surround the light emitting device arrays and to make
contact with the cooling member.
[0017] The annealing apparatus may further include a power supply
member connected to the power supply electrode via the cooling
member for supplying a power to the power supply electrode.
[0018] In accordance with a second aspect there is provided an
annealing apparatus including: a processing chamber for
accommodating an object to be processed; a heating source including
a plurality of light emitting devices and provided to face at least
one surface of the object to irradiate light on the object; a
light-transmitting member arranged in alignment with the heating
source to transmit the light emitted from the light emitting
devices; a support member for supporting the heating source; and a
power supply mechanism provided at a rear surface side of the
support member for supplying a power to the light emitting devices
via the support member.
[0019] The apparatus further includes a gas exhaust mechanism for
exhausting an inside of the processing chamber and a processing gas
supply mechanism for supplying a processing gas into the processing
chamber.
[0020] In accordance with the second aspect, the heating source may
include a plurality of light emitting device arrays each having: a
support body provided at the support member; a plurality of
electrodes formed on the support body; a plurality of light
emitting devices formed on the electrodes; and a power supply
electrode for supplying a power to the light emitting devices, and
wherein the power supply mechanism has a plurality of electrode
rods connected to the power supply electrode of each of the light
emitting device arrays and extending through the support member and
a plurality of power supply members through which to supply a power
to the electrode rods. The electrode rods and the power supply
members may be brought into contact with each other by
spring-biased pins.
[0021] The light emitting devices are preferably divided to be
arranged in each of power supply areas, wherein the power supply
area includes a plurality of the power supply electrodes in a
corresponding relationship therewith, and wherein the power supply
electrodes are arranged along a straight line. In this case, the
power supply electrodes may include a plurality of negative
electrodes and a common positive electrode. Further, the light
emitting devices may be provided in the power supply areas in a
form of a parallel connection of a plurality of sets of serially
connected light emitting devices.
[0022] The light emitting devices may be light-emitting diodes.
[0023] In accordance with the first aspect of the present
invention, the cooling member made of a material of high thermal
conductivity is provided to make direct contact with the heating
source and is cooled with a coolant in the cooling mechanism. This
makes it possible to effectively cool the light emitting devices by
using the cooling member having a heat capacity greater than that
of the light emitting devices. Thus the annealing apparatus is free
from the problem of reduced light energy efficiency attributable to
the reduction in light emission amount caused by the influence of
heat and is capable of maintaining stable performance.
[0024] The applicant of the prevent invention has filed Japanese
Patent Application No. 2006-184457 disclosing a technique for
solving the problem of reduced light energy efficiency by directly
cooling the LEDs as light emitting devices with a coolant. In the
technique, LEDs are cooled with high efficiency by bringing a
liquid coolant into direct contact with the LEDs. In order to
efficiently cool the LEDs, however, there is a need to bring the
coolant into contact with the light-emitting surfaces of the LEDs.
This may generate bubbles on the light-emitting surfaces, thereby
reducing the light-irradiating efficiency. Further, the cooling
efficiency may be insufficient without circulating a
low-temperature coolant across the light-emitting surfaces at all
times. This makes it necessary to circulate a large quantity of
coolant.
[0025] In accordance with the first aspect of the present
invention, the cooling member made of a material of high thermal
conductivity such as copper or the like are cooled by a coolant so
that cold heat can be accumulated in the cooling member. The light
emitting devices are cooled with the accumulated cold heat.
Therefore, the light emitting devices can be sufficiently cooled by
the accumulated cold energy without having to circulate a large
quantity of coolant during the annealing operation. In addition,
there is no need to bring the coolant into contact with the
light-emitting surfaces of the light emitting devices, thus
excluding the bubble generation problem.
[0026] In accordance with the second aspect of the present
invention, a power is supplied to the light emitting devices via
the support member at the rear surface side of the latter. This
makes it possible to supply the power to a multiplicity of light
emitting devices in an easy and simple manner.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a view showing a schematic configuration of an
annealing apparatus in accordance with an embodiment of the present
invention.
[0028] FIG. 2 is an enlarged cross sectional view illustrating a
heating source of the annealing apparatus shown in FIG. 1.
[0029] FIG. 3 is an enlarged cross sectional view illustrating the
portion through which to supply a power to LEDs of the annealing
apparatus shown in FIG. 1.
[0030] FIGS. 4A and 4B are views showing a control board of the
annealing apparatus shown in FIG. 1.
[0031] FIG. 5 is a view showing the arrangement of LEDs in an LED
array of the annealing apparatus shown in FIG. 1 and illustrating a
power supplying method.
[0032] FIG. 6 is a view showing a connection form of LEDs.
[0033] FIG. 7 is a bottom view illustrating the heating source of
the annealing apparatus shown in FIG. 1.
[0034] FIG. 8 is a view showing major parts of one modified example
of the annealing apparatus shown in FIG. 1.
[0035] FIG. 9 is a view showing major parts of another modified
example of the annealing apparatus shown in FIG. 1.
[0036] FIG. 10 is a view showing major parts of still another
modified example of the annealing apparatus shown in FIG. 1.
[0037] FIG. 11 is a view showing major parts of a still another
modified example of the annealing apparatus shown in FIG. 1.
[0038] FIG. 12 is a view showing major parts of a still another
modified example of the annealing apparatus shown in FIG. 1.
[0039] FIG. 13 is a view illustrating an exhaust mechanism for
exhausting the space to vacuum, the space being defined between a
cooling member and a light-transmitting member of the annealing
apparatus shown in FIG. 12 after the LED array is mounted in
place.
[0040] FIGS. 14A to 14I are views illustrating the steps of
assembling the LED array and the cooling member together and the
steps of mounting the LED array in place.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] Hereinafter, embodiments of the invention will be described
with reference to the accompanying drawings. An annealing apparatus
for annealing a wafer of which surface is implanted with impurities
will be described herein by way of example.
[0042] FIG. 1 is a sectional view showing a schematic configuration
of an annealing apparatus in accordance with the embodiment of the
present invention. FIG. 2 is an enlarged sectional view
illustrating a heating source of the annealing apparatus shown in
FIG. 1. FIG. 3 is an enlarged sectional view illustrating the
portion through which to supply a power to LEDs of the annealing
apparatus shown in FIG. 1. The annealing apparatus 100 includes an
airtightly sealed processing chamber 1 into which a wafer W is
loaded.
[0043] The processing chamber 1 has a cylindrical annealing portion
la in which the wafer W is positioned and a gas diffusing portion
1b formed in a doughnut shape outside the annealing portion 1a. The
gas diffusing portion 1b is greater in height than the annealing
portion la so that the processing chamber 1 has a H-shaped cross
section as a whole. The gas diffusing portion 1b of the processing
chamber 1 is defined by a chamber 2. Circular holes 3a and 3b are
formed in the top wall 2a and the bottom wall 2b of the chamber 2
in alignment with the annealing portion 1a. Cooling members 4a and
4b made of a highly conductive material such as copper or the like
are fitted into these holes 3a and 3b, respectively. The cooling
members 4a and 4b are provided with flange portions 5a and 5b that
make contact with the top wall 2a and the bottom wall 2b of the
chamber 2 via seal members 6a and 6b, respectively. The cooling
members 4a and 4b define the annealing portion 1a.
[0044] A support member 7 for horizontally mounting the wafer W
within the annealing portion la is provided in the processing
chamber 1. When replacing the wafer W, the support member 7 can be
moved up and down by a lifting mechanism (not shown). In the top
wall 2a of the chamber 2, there is formed a processing gas inlet
opening 8 through which a predetermined processing gas is
introduced from a processing gas supply mechanism (not shown). A
processing gas line 9 for supplying the processing gas is connected
to the processing gas inlet opening 8. A gas exhaust port 10 is
formed in the bottom wall 2b of the chamber 2. A gas exhaust line
11 leading to a gas exhaust unit (not shown) is connected to the
gas exhaust port 10.
[0045] In the side wall of the chamber 2, there is formed a
loading/unloading port 12 for loading/unloading the wafer W into
and out of the chamber 2. The loading/unloading port 12 can be
opened and closed by a gate valve 13. A temperature sensor 14 for
measuring the temperature of the wafer W mounted on the support
member 7 is provided in the processing chamber 1. The temperature
sensor 14 is connected to a measurement unit 15 disposed outside
the chamber 2. A temperature detection signal is output from the
measurement unit 15 to a process controller 60 which will be
described later.
[0046] On the surfaces of the cooling members 4a and 4b facing the
wafer W mounted on the support member 7, there are formed circular
recess portions 16a and 16b in alignment with the wafer W. Within
the recess portions 16a and 16b, heating sources 17a and 17b
including light-emitting diodes (LEDs) are provided to make direct
contact with the cooling members 4a and 4b.
[0047] Light-transmitting members 18a and 18b, through which the
lights emitted from the LEDs in the heating sources 17a and 17b are
transmitted to the wafer W, are screw-fixed to the surfaces of the
cooling members 4a and 4b facing the wafer W to cover the recess
portions 16a and 16b. The light-transmitting members 18a and 18b
are formed with a material that can effectively transmit the lights
emitted from the LEDs, e.g., quartz. A transparent resin 20 (see
FIGS. 1 and 3) is filled in a space defined by the recess portion
16a and the light-transmitting member 18a and that defined by the
recess portion 16b and the light-transmitting member 18b. As the
transparent resin 20, a silicone resin and an epoxy resin can be
used. In the resin filling process, it is desirable to fill the
transparent resin 20 while evacuating the spaces so that no bubble
should remain in the transparent resin 20.
[0048] Considering maintenance and repair, it is desirable to use,
as the transparent resin 20, a hard resin layer disposed at the
side of the LEDs and a soft resin layer disposed at the side of the
light-transmitting members 18a and 18b. That is, in a case where
some of the LEDs are replaced with new ones, it becomes difficult
to detach the light-transmitting members 18a and 18b if the
transparent resin 20 is formed of only a hard resin. In contrast,
if the transparent resin 20 is formed of only a soft resin, the
LEDs are pulled and detached together with the transparent resin 20
while detaching the light-transmitting members 18a and 18b, which
makes it difficult to reuse the LEDs. Use of the transparent resin
20 having two-layer structure makes it easy to detach the
light-transmitting members 18a and 18b and makes it possible to
protect the LEDs when detaching the light-transmitting members 18a
and 18b.
[0049] The cooling members 4a and 4b are provided with coolant flow
paths 21a and 21b through which a liquid phase coolant capable of
cooling the cooling members 4a and 4b to 0.degree. C. or less,
e.g., about -50.degree. C., flows. As the coolant a fluorine-based
inert liquid (a product name of Fluorinert, Galden or the like) can
be used. Coolant supply lines 22a and 22b and coolant discharge
lines 23a and 23b are connected to the coolant flow paths 21a and
21b. This makes it possible to circulate a coolant through the
coolant flow paths 21a and 21b, thereby cooling the cooling members
4a and 4b.
[0050] Cooling water flow lines 25, through which cooling water
kept at the room temperature flows, are formed in the top wall 2a
and the bottom wall 2b of the chamber 2. Accordingly, the
temperature of the chamber 2 is prevented from increasing
excessively.
[0051] As illustrated in FIG. 2 on an enlarged scale, each of the
heating sources 17a and 17b includes a plurality of LED arrays 34
each having a support body 32 made of an insulating material with
high thermal conductivity, typically an AlN-based ceramic material,
and a multiplicity of LEDs 33 mounted on the support body 32. The
rear surfaces of the LED arrays 34 are brought into
surface-to-surface contact with the bottom surface of the cooling
member 4a of the heating source 17a and with the top surface of the
cooling member 4b of the heating source 17b by, e.g.,
soldering.
[0052] Highly conductive electrodes 35, copper plated with gold,
are provided between the support body 32 and the LEDs of each of
the LED arrays 34 in a surface-to-surface contact state. Electrodes
35 and adjacent LEDs 33 are connected by a wire 36. Thus, cold heat
is efficiently transferred from the coolant to the cooling members
4a and 4b of high thermal conductivity and then reaches the LEDs 33
via the support body 32 and the electrodes 35 that have high
thermal conductivity and make surface-to-surface contact (total
contact) with each other. Consequently, the LEDs 33 are cooled in a
high efficient manner.
[0053] Control boxes 37a and 37b for controlling the supply of
electric power to the LEDs 33 are provided above the cooling member
4a and below the cooling member 4b, respectively. Wiring lines
extending from a power source (not shown) are connected to the
control boxes 37a and 37b. Thus, the supply of the electric power
to the LEDs 33 is controlled by the control boxes 37a and 37b.
[0054] As illustrated in FIG. 3 on an enlarged scale, electrode
rods 38 (not shown in FIG. 2) extending through the cooling members
4a and 4b are connected to the electrodes 35. A plurality of, e.g.,
eight, electrode rods are provided in each of the LED arrays 34
(only two electrode rods 38 are shown in FIGS. 1 and 3). Each of
the electrode rods 38 is covered with a protection cover 38a made
of an insulating material. Each of the electrode rods 38 extends
from the vicinity of the electrodes 35 to the upper end portion of
the cooling member 4a or the lower end portion of the cooling
member 4b and is screw coupled with an accommodating member 39. An
insulating ring 40 is interposed between the accommodating member
39 and each of the cooling members 4a and 4b. The tip end portion
of each of the electrode rods 38 is soldered to one of the
electrodes 35. In this regard, solder is filled in gaps between the
protection cover 38a and each of the cooling members 4a and 4b and
in gaps between the protection cover 38a and each of the electrode
rods 38, thereby forming a so-called feed-through.
[0055] A plurality of control boards 42 is provided in each of the
control boxes 37a and 37b. As shown in FIGS. 4A and 4B, each of the
control boards 42 includes a connecting member 42a to which a power
supply member 41 corresponding to each electrode rod 38 is
connected and a power supply connector 43 to which a wiring line
extending from a power supply is connected. Each of the power
supply members 41 extends downwards to be connected with the
accommodating member 39 coupled with each of the electrode rods
38.
[0056] Each of the power supply members 41 is covered with a
protection cover 44 made of an insulating material. Each of the
power supply members 41 is provided at its tip end with a pogo pin
(spring pin) 41a that makes contact with the corresponding
accommodating member 39. This ensures that a power is supplied from
the control boxes 37a and 37b to the LEDs 33 via the power supply
members 41, the electrode rods 38 and the electrodes 35 of the
heating sources 17a and 17b. Responsive to the supply of a power,
the LEDs 33 emit light to heat the surface of the wafer W,
consequently subjecting the wafer W to annealing. The pogo pin 41a
is spring-biased toward the accommodating member 39. This makes
sure that the power supply members 41 and the electrode rods 38 are
kept in contact with each other even when the control boards 42 are
installed out of alignment. Although three power supply members 41
are shown in FIGS. 4A and 4B, this is for the sake of
illustration.
[0057] Each of the LED arrays 34 has a hexagonal shape as
illustrated in FIG. 5 which shows the arrangement of the LEDs 33 in
each of the LED arrays 34 and a power supplying method. In each of
the LED arrays 34, those are important that a sufficiently high
power is supplied to the LEDs 33 and further that a large number of
the LEDs 33 is provided while reducing the area loss of a power
supplying area. In order to supply a sufficiently high power, each
of the LED arrays 34 is divided into six power supply areas. More
specifically, two areas 341 and 342 are defined by bisecting each
of the LED arrays 34 of hexagonal shape along a line joining the
midpoints of two opposing sides. The area 341 is divided into three
power supply areas 341a, 341b and 341c and the area 342 is divided
into three power supply areas 342a, 342b and 342c.
[0058] At this time, each of the areas 341 and 342 is divided in
the following manner. Taking the area 341 as an example, the power
supply area 341a is a generally triangular area defined by two
non-bisected adjoining sides of a hexagon and a rectilinear line
joining the distal ends of these adjoining sides. The power supply
areas 341b and the 341c are the generally rectangular areas formed
by bisecting the remaining area of the area 341 along a rectilinear
line parallel to the bisected opposing sides of the hexagon. This
holds true in case of the area 342. Specifically, the power supply
area 342a is formed of a generally triangular area and the power
supply areas 342b and 342c are formed of generally rectangular
areas formed by bisecting the remaining area of the area 342.
[0059] As the electrodes through which a power is supplied to these
power supply areas, three negative electrodes 51a, 51b and 51c and
a single common positive electrode 52 are disposed along a straight
line in the area 341. Similarly, three negative electrodes 53a, 53b
and 53c and a single common positive electrode 54 are arranged
along a straight line in the area 342. The reason for arranging
these electrodes along a straight line is that there is a need to
provide the electrode rods 38 in a region between the coolant flow
paths 21a and 21b of the cooling members 4a and 4b.
[0060] The common positive electrode 52 supplies a power to the
power supply areas 341a, 341b and 342c therethrough, whereas the
common positive electrode 54 supplies a power to the power supply
areas 342a, 342b and 341c therethrough.
[0061] Four hundreds of LEDs 33 are arranged in each of the power
supply areas. As can be seen in FIG. 6, the LEDs 33 of each of the
power supply areas are of a parallel connection of two sets of
serially connected LEDs. This makes it possible to reduce the
variation between the LEDs and the variation in voltage.
[0062] The LED arrays 34 having the structure set forth above are
provided as illustrated in FIG. 7, for example. 2000/5000 LEDs 33
(2400 LEDs 33 in the afore-mentioned example) are mounted in each
of the LED arrays 34. The LEDs 33 used herein may emit light whose
wavelength is in a range between an ultraviolet ray wavelength and
an infrared ray wavelength, preferably in a range of from 0.36 to
1.0 .mu.m. Examples of such LEDs 33 include compound semiconductors
based on GaN, GaAs or the like.
[0063] Since the cooling members 4a and 4b are cooled, the regions
in which the power supply members 41 are provided are maintained at
a low temperature by a cold heat of the cooling members 4a and 4b.
Therefore, the power supply members 41 can suffer from electric
trouble due to dew condensation if an air of high humidity exists
near the power supply members 41. For that reason, a dry gas is
introduced into the space between the control boxes 37a and 37b and
the cooling members 4a and 4b through gas lines 45a and 45b (see
FIG. 1).
[0064] Referring again to FIG. 1, the respective component parts of
the annealing apparatus 100 are connected to and controlled by a
process controller 60 provided with a microprocessor (i.e., a
computer). For example, the power control of the control boxes 37a
and 37b, the drive system control and the gas supply control are
performed by the process controller 60. A user interface 61 is
connected to the process controller 60, wherein the user interface
61 includes a key board for a process manager to input commands to
operate the annealing apparatus 100 and a display for showing an
operational status of the annealing apparatus 100.
[0065] A storage unit 62 is connected to the process controller 60.
The storage unit 62 stores a control program for enabling the
process controller 60 to control various kinds of processing
performed in the annealing apparatus 100 and a program, i.e.,
recipes to be used in operating the respective component parts of
the annealing apparatus 100 to carry out processes in accordance
with processing conditions. The recipes can be stored in a hard
disk or a semiconductor memory, or can be set at a certain position
of the storage unit 62 while being recorded on a portable storage
medium such as a CDROM, a DVD or the like.
[0066] Alternatively, the recipes may be suitably transmitted from
other devices to the annealing apparatus 100 through, e.g., a
dedicated communication line. If necessary, arbitrary one of the
recipes is retrieved from the storage unit 62 under the
instructions inputted through the user interface 61 to be executed
by the process controller 60. Thus the annealing apparatus 100
performs desired processing under the control of the process
controller 60.
[0067] Hereinafter, there will be described an annealing operation
performed by the annealing apparatus 100. First, the gate valve 13
is opened. Then, the wafer W is loaded into the processing chamber
1 through the loading/unloading port 12 to be mouned on the support
member 7. Then the gate valve 13 is closed to keep the processing
chamber 1 in an airtightly sealed state. While a specific
processing gas, e.g., an argon gas or a nitrogen gas, is introduced
from a processing gas supply unit (not shown) into the processing
chamber 1 via a processing gas line 9 and a processing gas inlet
opening 8, the processing chamber 1 is evacuated through the gas
exhaust port 11 by a gas exhaust unit (not shown). Accordingly, the
pressure of processing chamber 1 is maintained at a predetermined
value in a range of, e.g., from 100 to 10000 Pa.
[0068] In the cooling members 4a and 4b, a liquid phase coolant,
e.g., a fluorine-based inert liquid (a product name of Fluorinert,
Galden or the like) circulates in the coolant flow paths 21a and
21b, thereby cooling the LEDs 33 to a specific temperature of
0.degree. C. or less, preferably -50.degree. C. or less.
[0069] Then, the LEDs 33 are turned on by supplying a power from a
power supply (not shown) to the LEDs 33 via the control boxes 37a
and 37b, the power supply members 41, the electrode rods 38 and the
electrodes 35.
[0070] If the LEDs 33 are maintained at a room temperature, the
light emission amount of the LEDs 33 is reduced by a self-generated
heat. In the present embodiment, however, a coolant is allowed to
flow through the cooling members 4a and 4b so that the LEDs 33 can
be cooled with a cold heat transferred via the cooling members 4a
and 4b, the support bodies 32 and the electrodes 35 as shown in
FIG. 2. This makes it possible to cool the LEDs 33 with increased
efficiency.
[0071] In a technique disclosed in Japanese Patent Application No.
2006-184457, LEDs are cooled with increased efficiency by bringing
a liquid coolant into direct contact with the LEDs. In order to
efficiently cool the LEDs, however, there is a need to bring the
coolant into contact with the light-emitting surfaces of the LEDs.
This may generate bubbles on the light-emitting surfaces, thereby
reducing the light-irradiating efficiency. Furthermore, the cooling
efficiency may be reduced unless circulating a low-temperature
coolant across the light-emitting surfaces at all times. Therefore,
a large quantity of coolant needs to be circulated.
[0072] Therefore, in the present invention, the cooling members 4a
and 4b made of a material of high thermal conductivity such as
copper or the like are cooled by a coolant so that cold heat can be
accumulated in the cooling members 4a and 4b to cool the LEDs 33 by
the accumulated cold heat. The cooling members 4a and 4b have a
heat capacity far greater than that of the LEDs 33. The LEDs 33 are
cooled by supplying the cold heat of the cooling members 4a and 4b
thereto through the electrodes 35 and the support bodies 32, both
of which exhibit high thermal conductivity and make
surface-to-surface contact with each other.
[0073] Therefore, the LEDs 33 can be sufficiently cooled by the
accumulated cold heat without having to circulate a large quantity
of coolant during the annealing operation. In addition, there is no
need to bring the coolant into contact with the light-emitting
surfaces of the LEDs 33, thus preventing the bubble generation. The
annealing time is approximately one second per sheet of wafer and
the wafer replacing time is about thirty seconds. Thus it is
possible to design the annealing apparatus 100 so that the cooling
members 4a and 4b can be cooled for the wafer replacing time, i.e.,
thirty seconds, and the LEDs 33 can be maintained at 100.degree. C.
or less during the annealing operation.
[0074] In the conventional LED-type annealing apparatus, the
differential pressure between a processing chamber kept in a vacuum
and an LED accommodating space kept at an atmospheric pressure is
withstood by a light-transmitting member made of quartz or the
like. Therefore, there is a need to increase the thickness of the
light-transmitting member. In the present embodiment, the
differential pressure between the processing chamber 1 and the
atmosphere is withstood by the metal-made cooling members 4a and
4b, which makes it possible to reduce the thickness of the
light-transmitting members 18a and 18b. This restrains accumulation
of heat in the light-transmitting members 18a and 18b, thereby
making it possible to fully assure thermal insulation between the
portions cooled by the cooling members 4a and 4b and the heating
portions in the processing chamber 1.
[0075] With a view to further enhance the thermal insulation, clamp
screws of the light-transmitting members 18a and 18b may preferably
be made of a resin or a ceramic of low thermal conductivity.
Reduction in thickness of the light-transmitting members 18a and
18b ensures that heat is efficiently radiated from the wafer W
toward the cooling members 4a and 4b, thereby improving cooling
characteristics of the wafer.
[0076] Use of AlN as the support bodies 32 of the LED arrays allows
the support bodies 32 not only to reflect the light emitted from
the LEDs 33 but also to absorb the radiant heat from the wafer W
heated to about 1000.degree. C. This also improves the heating and
cooling characteristics.
[0077] Since a power is supplied to the LEDs 33 of the LED arrays
34 via the power supply members 41 and the electrode rods 38 at the
rear surface side of the cooling members 4a and 4b, it is possible
to supply a power to a multiplicity of LEDs 33 in a relatively easy
and simple manner. Further, since the pogo pins 41a is used in
bringing the power supply members 41 and the accommodating members
39 into contact with each other, it is possible to simply and
reliably provide the contact between the power supply members 41
and the electrode rods 38 with the biasing force of a spring even
when the control boards 42 are installed out of alignment.
[0078] Next, description will be made on certain modified examples
of the annealing apparatus of in accordance with the
above-described embodiment.
[0079] In a modified example shown in FIG. 8, the spaces between
the cooling members 4a and 4b and the light-transmitting members
18a and 18b are filled with an argon gas 46 in place of a resin. In
this case, a small amount of ambient air may possibly be introduced
through the feed-through. Therefore, it is preferable that the LED
arrays 34 are subjected to dampproof coating.
[0080] In a modified example shown in FIG. 9, there are provided a
vacuum pump 48 for evacuating the spaces between the cooling
members 4a and 4b and the light-transmitting members 18a and 18b
and a gas introduction mechanism 49 for introducing an argon gas or
the like into the spaces. Therefore, the spaces are kept in a
vacuum atmosphere.
[0081] In a modified example shown in FIG. 10, transparent
electrodes 50 made of ITO (Indium Tin Oxide), IZO (Indium Zinc
Oxide) or the like are formed on the light-emitting surfaces of the
LEDs 33 and are bonded to the light-transmitting members 18a and
18b, instead of interconnecting the electrodes 35 and the LEDs 33
with the wire 36.
[0082] Boiling heat transfer may occur by controlling the coolant
temperature during the cooling operation depending on the boiling
point of the coolant. The boiling heat transfer allows the coolant
to have a temperature higher than the boiling point thereof.
Therefore, the cooling operation can be performed by the
evaporative latent heat as well as the cold heat of the coolant,
which makes it possible to realize a highly efficient cooling
operation.
[0083] A modified example illustrated in FIG. 11 is made by taking
into account the efficient release of light and the ease of
maintenance and repair.
[0084] In order to efficiently release the light, it is preferable
that the transition from the refractive index of a solid
light-emitting material to the refractive index of a
light-irradiated space occurs gradually. This is the reason why the
resin such as silicone or the like is filled around the LEDs 33 and
the light-transmitting members 18a and 18b are made of quartz in
the embodiment shown in FIG. 1.
[0085] In this case, however, the ease of maintenance and repair
becomes deteriorated due to the possibility that, when detaching
the light-transmitting members 18a and 18b for maintenance
purposes, the gel-like resin is peeled off together with the
light-transmitting members 18a and 18b, eventually destroying the
normal LEDs as well as the defective ones. For realization of the
annealing apparatus as shown in FIG. 1, there is a need to use
several hundreds of thousands of LEDs. Since it is impossible for
all of the LEDs to normally operate for a long period of time, it
is preferable that the annealing apparatus is designed to replace
the LEDs on a unit-by-unit basis.
[0086] If only the ease of maintenance and repair is taken into
account, it would be desirable to fill the gas as in the modified
example illustrated in FIG. 8. However, this is undesirable in that
the transition of the refractive indices does not occur gradually,
which leads to reduction in the light efficiency.
[0087] In a modified example illustrated in FIG. 11, therefore, a
liquid 71, e.g., such as Fluorinert, Galden or Novec is deaerated
in advance and then filled in the space where the LEDs exist. The
liquid 71 is a liquid in which a gas is insoluble or hardly solved.
The liquid 71 has a refractive index, which is equivalent to the
midpoint value between the refractive indices of the LEDs and the
quartz forming the light-transmitting members, and a low vapor
pressure. Since the liquid 71 is deaerated and used merely as a
filler with no cooling function, it seldom generates bubbles which
may reduce the light irradiation efficiency.
[0088] In this modified example, a thermally conductive layer 72
with high thermal conductivity such as a silver paste layer or a
silicon grease layer is formed on the rear surfaces of the LED
arrays 34. The LED arrays 34 are mounted on the cooling members 4a
and 4b by screws 73. When performing maintenance and repair or
replacement of the LEDs, the LED arrays 34 can be easily detached
by detaching the light-transmitting members 18a and 18b, draining
the liquid 71 and loosening the screws 73. In this case, the screws
73 may be used independently, but it is preferable that the screws
73 are used in combination with washers or leaf springs made of a
material of high Young's modulus, e.g., Si.sub.3N.sub.4.
[0089] In this modified example, each of the LED arrays 34 is
provided with an external frame 74 leading to each of the
light-transmitting members 18a and 18b. The external frame serves
as a reflector plate and a support member for supporting each of
the light-transmitting members 18a and 18b. This makes it possible
to further increase the light irradiation efficiency and to further
reduce the thickness of the light-transmitting members 18a and 18b.
The external frame 74 has liquid through holes 75 through which the
liquid 71 is dispersed over the space where the LEDs 33 exists. The
operation of filling the liquid 71 is performed by a suitable
method after the light-transmitting members 18a and 18b are mounted
in place.
[0090] FIG. 12 illustrates a modified example by which the ease of
maintenance and repair, particularly the ease of replacement of the
LEDs, is increased without reducing the cooling efficiency.
[0091] It is important to cool the LEDs 33 when they emit light
with high power. For that reason, there is a need to strongly bond
the LEDs 33 to the cooling surfaces by soldering or other bonding
methods. In case of an apparatus that performs rapid heating of a
wafer by using LEDs, the repair and replacement of LEDs is very
important and therefore the ease of replacement needs to be higher
than that offered by the configuration illustrated in FIG. 11.
[0092] In a modified example illustrated in FIG. 12, a heating
source 17a or 17b includes a plurality of LED arrays 34', each of
which is formed of a unit including: a support body 32 disposed to
support a multiplicity of LEDs 33 and made of a material with high
thermal conductivity, e.g., AlN; a thermal diffusion member 81
soldered or brazed to the rear surface of the support body 32 and
made of a material of high thermal conductivity, e.g., Cu; a resin
layer 82 provided to cover the LEDs 33 supported by the support
body 32 and made of, e.g., a silicon-based transparent resin (a
resin lens or a resin mold); and a power supply electrode 83 for
supplying a power to the LEDs 33, the power supply electrode 83
being inserted into and penetrated through a through-hole 81a of
the thermal diffusion member 81 and a through-hole 32a of the
support body 32. The LED arrays 34' are fixed by screws 84 to the
cooling member 4a or 4b via paste such as silicon grease, silver
paste or the like of high thermal conductivity. A seal ring 89 is
interposed between the cooling member 4a or 4b and the thermal
diffusion member 81.
[0093] The power supply electrode 83 is provided with ports
disposed at a corresponding position at a rear side of the thermal
diffusion member 81. Therefore, each of the power supply members
41' passing through the cooling members 4a and 4b (only 4a shown in
FIG. 12) is connected to the power supply electrode 83 via each of
the ports 85.
[0094] Each of the cooling members 4a and 4b includes a plurality
of attachment portions 86 to which the LED arrays 34' are attached.
Each of the attachment portions 86 has a frame member 87 that
functions as a spacer making contact with the light-transmitting
member 18a or 18b. The frame member 87 is attached to surround the
attachment region of each of the LED arrays 34'. A space 88 kept in
vacuum exist between the resin layer 82 of each of the LED arrays
34' attached to the attachment portions 86 and the
light-transmitting member 18a or 18b.
[0095] As shown in FIG. 13, the cooling member 4a has a gas passage
93 communicating with a space 92 defined by a recess 16a when the
light-transmitting member 18a is mounted to the cooling member 4a.
A gas exhaust line 94 is connected to the gas passage 93 of the
cooling member 4a. The gas passage 93 and the gas exhaust line 94
form a gas exhaust path. A buffer member 95 having a buffer space
greater in diameter than the gas exhaust line 94 is provided during
the gas exhaust line 94. The space 88 is evacuated by a gas exhaust
unit 96 via the gas passage 93, the gas exhaust line 94 and the
buffer member 95 to be kept in a vacuum state. This is also applied
to the cooling member 4b. The space 88 is small and therefore would
be hardly depressurized by a typical evacuation operation.
Provision of the buffer space makes it possible to easily evacuate
the space 88.
[0096] A gas exhaust hole 91 is formed in the frame member 87 so
that all of the spaces 88 can be evacuated via the gas exhaust hole
91.
[0097] In case of the embodiment shown in FIG. 1, a resin is filled
between the cooling members 4a and 4b and the light-transmitting
members 18a and 18b. Due to the increase in the filling quantity of
the resin, a difficulty may be encountered in filling the resin and
the efficiency of the LEDs may be reduced due to bubbles or the
like. In the modified example illustrated in FIGS. 12 and 13,
however, the resin layer 82 is formed in a small thickness to
merely cover the LEDs 33. The remaining space is evacuated as
mentioned above. This makes it possible to avoid the drawbacks
inherent in the embodiment shown in FIG. 1.
[0098] Next, the steps of assembling the LED arrays 34' and the
cooling members 4a and 4b together and the steps of mounting the
LED arrays 34' in place will be described with reference to FIGS.
14A to 14I.
[0099] First, the support body 32 having a hexagonal shape is cut
from an AlN-made plate material and the through-holes 32a through
which the power supply electrodes and the screws are inserted are
formed in the support body 32 (see FIG. 14A). Then, the front
surface of the copper-made thermal diffusion member 81 having the
same shape as the support body 32 and having the through-holes 81a
formed in alignment with the through-holes 32a is bonded to the
rear surface of the support body 32 by the soldering that makes use
of solder paste (see FIG. 14B). The power supply electrodes 83 are
inserted into the through-holes 32a and 81a to pass through the
support body 32 and the thermal diffusion member 81 and are
soldered to the support body 32 (see FIG. 14C).
[0100] Thereafter, solder paste is put on the front surface of the
support body 32 and the LEDs 33 are placed on the solder paste. In
this state, the support body 32 and the LEDs 33 are heat-treated
and soldered in a batch furnace (see FIG. 14D). A bonding operation
is performed by using the wire 36 (see FIG. 14E). In order to
protect the LEDs 33 and to adjust the refractive index, the LEDs 33
are covered with a transparent resin (a resin lens or a resin mold)
to thereby form the resin layer 82. An epoxy-based resin is filled
in the space between the power supply electrodes 83 and the
through-holes 81a to provide a hermetic seal, thereby producing the
LED array 34' (see FIG. 14F). Concurrently with the above
operation, the cooling member 4a or 4b is fabricated (see FIG.
14G).
[0101] Thereafter, the LED array 34' is mounted to the cooling
member 4a or 4b (see FIG. 14H). The power supply members 41' are
connected to the power supply electrodes 83 and the LED array 34'
is fixed to the cooling member 4a or 4b by screws 84 (see FIG.
14I).
[0102] The operation of mounting the LED array 34' is completed
through the steps described above. Subsequently, the
light-transmitting member 18a or 18b is mounted in place to
establish the state shown in FIG. 12.
[0103] As described above, the LED array 34' is formed into a unit
and attached to the cooling member 4a or 4b by the screws 84 in the
annealing apparatus shown in FIG. 12. Therefore, the LED array 34'
can be attached and detached with ease. Since the LED array 34' can
be easily replaced on a unit-by-unit basis when there is a need to
replace the LEDs 33, it is possible to greatly increase the ease of
maintenance and repair. Further, the AlN-made support body and the
copper-made thermal diffusion member 81 are brought into
surface-to-surface contact with each other by soldering (with cream
solder). The thermal diffusion member 81 and the cooling member 4a
or 4b are also brought into surface-to-surface contact with each
other by using paste such as silicon grease, silver paste or the
like of high thermal conductivity. Therefore, the LEDs 33 can be
cooled with a reduced thermal resistance.
[0104] In the space defined between the cooling member 4a or 4b and
the light-transmitting member 18a or 18b, only the portion where
the LEDs 33 is installed is covered with the resin layer 82. The
remaining space 82 is evacuated. This makes it possible to avoid
the difficulty which can be encountered when the whole space is
filled with a resin as mentioned earlier. It is also possible to
mitigate the reduction in light irradiation efficiency which can be
caused by the difference in refractive index between the LEDs 33
and the vacuum space when the whole space is evacuated without
forming the resin layer 82.
[0105] In other words, use of the resin layer 82 provides a
structure in which the LEDs 33, the resin layer 82 and the space 88
have gradually decreasing refractive indices. The total reflection
of light which can arise from the big difference between the
refractive indices is hard to occur, thereby preventing the
reduction in light irradiation efficiency.
[0106] The present invention is not limited to the embodiment and
the modified examples described above but may be changed or
modified in many different forms. For example, although the
afore-mentioned embodiment is directed to an example in which the
heating sources with LEDs are provided at the opposite sides of the
wafer as an object to be processed, it may be possible to provide a
single heating source at only one side of the wafer. Although LEDs
are used as the light emitting devices in the afore-mentioned
embodiment, it may be possible to use other light emitting devices
such as a semiconductor laser and the like. The object to be
processed is not limited to the semiconductor wafer but may be
other objects such as a glass substrate for flat panel displays and
the like.
INDUSTRIAL APPLICABILITY
[0107] The present invention can be appropriately used to perform
rapid heating, e.g., in annealing a semiconductor wafer after
impurities are implanted into the same.
* * * * *