U.S. patent application number 11/119218 was filed with the patent office on 2006-11-02 for termoelectric heating and cooling apparatus for semiconductor processing.
This patent application is currently assigned to Taiwan Semiconductor Manufacturing Co., Ltd.. Invention is credited to Jerry Hwang, Chin-Hsien Lin, Yu-Liang Lin.
Application Number | 20060242967 11/119218 |
Document ID | / |
Family ID | 37195422 |
Filed Date | 2006-11-02 |
United States Patent
Application |
20060242967 |
Kind Code |
A1 |
Lin; Yu-Liang ; et
al. |
November 2, 2006 |
Termoelectric heating and cooling apparatus for semiconductor
processing
Abstract
A thermoelectric wafer chuck is disclosed. The thermoelectric
wafer chuck includes a wafer support surface for supporting a
wafer; and a thermoelectric module provided in thermal contact with
the wafer support surface for heating and/or cooling the wafer
support surface and wafer.
Inventors: |
Lin; Yu-Liang; (Hsin-Chu,
TW) ; Lin; Chin-Hsien; (Hsin-Chu, TW) ; Hwang;
Jerry; (Hsin-Chu, TW) |
Correspondence
Address: |
TUNG & ASSOCIATES
Suite 120
838 W. Long Lake Road
Bloomfield Hills
MI
48302
US
|
Assignee: |
Taiwan Semiconductor Manufacturing
Co., Ltd.
|
Family ID: |
37195422 |
Appl. No.: |
11/119218 |
Filed: |
April 28, 2005 |
Current U.S.
Class: |
62/3.3 |
Current CPC
Class: |
H01L 35/32 20130101;
H01L 35/325 20130101; H01L 21/67109 20130101 |
Class at
Publication: |
062/003.3 |
International
Class: |
F25B 21/02 20060101
F25B021/02 |
Claims
1. A thermoelectric wafer chuck comprising: a wafer support surface
for supporting a wafer; and a thermoelectric module provided in
thermal contact with said wafer support surface.
2. The thermoelectric wafer chuck of claim 1 wherein said
thermoelectric module comprises a single-layer thermoelectric
module.
3. The thermoelectric wafer chuck of claim 2 wherein said
thermoelectric module defines a plurality of heating zones on said
wafer support surface.
4. The thermoelectric wafer chuck of claim 1 wherein said
thermoelectric module comprises a stacked thermoelectric
module.
5. The thermoelectric wafer chuck of claim 4 wherein said
thermoelectric module defines a plurality of heating zones on said
wafer support surface.
6. The thermoelectric wafer chuck of claim 1 further comprising a
chuck base and wherein said wafer support surface is carried by
said chuck base.
7. The thermoelectric wafer chuck of claim 6 further comprising at
least one fluid channel extending through said chuck base.
8. The thermoelectric wafer chuck of claim 7 wherein said at least
one fluid channel extends through said chuck base in a single-loop
configuration.
9. The thermoelectric wafer chuck of claim 7 wherein said at least
one fluid channel extends through said chuck base in a multi-loop
configuration.
10. A thermoelectric wafer chuck comprising: a chuck base; at least
one coil-free fluid channel extending through said chuck base; and
a wafer support surface carried by said chuck base.
11. The thermoelectric wafer chuck of claim 10 wherein said at
least one coil-free fluid channel extends through said chuck base
in a single-loop configuration.
12. The coil-free thermoelectric wafer chuck of claim 10 wherein
said at least one coil-free fluid channel extends through said
chuck base in a multi-loop configuration.
13. The coil-free thermoelectric wafer chuck of claim 10 further
comprising a thermoelectric module provided in said chuck base in
thermal contact with said wafer support surface.
14. The coil-free thermoelectric wafer chuck of claim 13 wherein
said thermoelectric module comprises a single-layer thermoelectric
module.
15. The thermoelectric wafer chuck of claim 14 wherein said
thermoelectric module defines a plurality of heating zones on said
wafer support surface.
16. The thermoelectric wafer chuck of claim 13 wherein said
thermoelectric module comprises a stacked thermoelectric
module.
17. The thermoelectric wafer chuck of claim 16 wherein said
thermoelectric module defines a plurality of heating zones on said
wafer support surface.
18. A thermoelectric wafer chuck comprising: a chuck base; a wafer
support plate having a wafer support surface for supporting a wafer
carried by said chuck base; a chuck interior defined between said
chuck base and said wafer support plate; and a thermoelectric
module provided in said chuck interior in thermal contact with said
wafer support surface.
19. The thermoelectric wafer chuck of claim 18 further comprising
at least one fluid channel provided in said chuck base.
20. The thermoelectric wafer chuck of claim 19 wherein said at
least one coolant channel extends through said chuck base in a
single-loop configuration.
21. The thermoelectric wafer chuck of claim 19 wherein said at
least one coolant channel extends through said chuck base in a
multi-loop configuration.
22. The thermoelectric wafer chuck of claim 18 wherein said
thermoelectric module comprises a single-layer thermoelectric
module.
23. The thermoelectric wafer chuck of claim 22 wherein said
thermoelectric module defines a plurality of heating zones on said
wafer support surface.
24. The thermoelectric wafer chuck of claim 18 wherein said
thermoelectric module comprises a stacked thermoelectric
module.
25. The thermoelectric wafer chuck of claim 24 wherein said
thermoelectric module defines a plurality of heating zones on said
wafer support surface.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to devices for heating wafers
in semiconductor processing. More particularly, the present
invention relates to a thermoelectric heating and cooling apparatus
which is suitable for selectively heating or cooling a wafer during
semiconductor processing and is characterized by fast and dynamic
temperature control capability and multi-zone implementation.
BACKGROUND OF THE INVENTION
[0002] In the fabrication of semiconductor integrated circuits,
metal conductor lines are used to interconnect the multiple
components in device circuits on a semiconductor wafer. A general
process used in the deposition of metal conductor line patterns on
semiconductor wafers includes deposition of a conducting layer on
the silicon wafer substrate; formation of a photoresist or other
mask such as titanium oxide or silicon oxide, in the form of the
desired metal conductor line pattern, using standard lithographic
techniques; subjecting the wafer substrate to a dry etching process
to remove the conducting layer from the areas not covered by the
mask, thereby leaving the metal layer in the form of the masked
conductor line pattern; and removing the mask layer typically using
reactive plasma and chlorine gas, thereby exposing the top surface
of the metal conductor lines. Typically, multiple alternating
layers of electrically conductive and insulative materials are
sequentially deposited on the wafer substrate, and conductive
layers at different levels on the wafer may be electrically
connected to each other by etching vias, or openings, in the
insulative layers and filling the vias using aluminum, tungsten or
other metal to establish electrical connection between the
conductive layers.
[0003] Deposition of conductive layers on the wafer substrate and
etching of the layers frequently requires heating and/or chilling
of the wafer, depending on the process. Conventional wafer chucks
in semiconductor processing chambers which require wafer heating
and/or cooling are typically provided with an interior coil through
which a heating or cooling liquid or gas is distributed to heat or
cool the wafer resting on the chuck through conduction. However,
the conventional wafer chucks suffer from various disadvantages,
including low wafer-heating response and control, little or no
cool-down function, and low wafer temperature control accuracy.
Therefore, a new and improved apparatus is needed to facilitate
selective heating and/or cooling of wafers during semiconductor
processing.
SUMMARY OF THE INVENTION
[0004] The present invention is generally directed to a
thermoelectric wafer chuck for semiconductor processing. The
thermoelectric wafer chuck includes a chuck base and a wafer
support surface. Fluid channels extend through the chuck base for
distribution of a heating or cooling liquid. A thermoelectric
module is provided in thermal contact with the wafer support
surface. In use, the thermoelectric wafer chuck is capable of
heating a wafer resting on the wafer support surface as the
thermoelectric module converts electrical energy into thermal
energy according to the Peltier effect. A heating fluid may
alternatively or additionally be distributed through the fluid
channels in the chuck base to heat the wafer. The wafer is cooled
typically by reverse flow of current through the thermoelectric
module, by distribution of a cooling fluid through the fluid
channels, or both. The thermoelectric wafer chuck facilitates
rapid, dynamic and multi-zone temperature control capability of a
wafer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The invention will now be described, by way of example, with
reference to the accompanying drawings, in which:
[0006] FIG. 1 is a perspective view of a section of a
thermoelectric module suitable for the thermoelectric wafer chuck
of the present invention;
[0007] FIG. 2 is a front view of the thermoelectric module of FIG.
1;
[0008] FIG. 2A is a top view of the thermoelectric module, with a
portion of the top isolation plate removed therefrom;
[0009] FIG. 3 is a perspective view of a multi-stack thermoelectric
module;
[0010] FIG. 4 is a perspective view of a section of a
thermoelectric wafer chuck of the present invention;
[0011] FIG. 5 is a top perspective view, partially in section, of a
processing chamber in which the thermoelectric wafer chuck of the
present invention is installed, more particularly illustrating flow
of a processing gas into the chamber; and
[0012] FIG. 6 is a bottom perspective view, partially in section,
of the processing chamber of FIG. 5, illustrating multiple heat
cells in the thermoelectric module of the thermoelectric chuck.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The present invention is generally directed to a
thermoelectric wafer chuck for the heating and/or cooling of wafers
during semiconductor processing. The thermoelectric wafer chuck
includes a chuck base and a wafer support surface. Fluid channels
extend through the chuck base in a single-loop or multi-loop
configuration for distribution of a cooling or heating liquid
through the chuck base. A thermoelectric module is provided in the
wafer chuck, in thermal contact with the wafer support surface. The
thermoelectric module includes multiple p-type semiconductor
connectors and n-type semiconductor connectors adjacent ones of
which are alternately connected to each other through top conductor
plates and bottom conductor plates. Using the Peltier effect, the
thermoelectric module converts electrical energy into thermal
energy and is capable of heating a wafer resting on the wafer
support surface. Alternatively or additionally, the wafer may be
heated by the distribution of a heating fluid through the fluid
channels of the chuck base. The wafer may be cooled by reverse flow
of electrical current through the thermoelectric module, by
distribution of a coolant fluid through the coolant channels in the
chuck base, or both. The thermoelectric module imparts rapid,
dynamic and multi-zone temperature control capability to the
thermoelectric wafer chuck.
[0014] The Peltier effect involves the creation of a heat
differential from an electric voltage differential. When an
electrical current is passed through connectors made of p-type and
n-type semiconductors which are connected to each other at two
junctions, the current drives a transfer of heat from one junction
to the other. Accordingly, one junction of each connector cools
while the other heats. P-type silicon typically has a positive
Peltier coefficient (though not above .about.550 K), whereas the
Peltier coefficient of n-type silicon is typically negative.
[0015] As current flows through the connector, the semiconductor
material of the connector tends to return to the electron
equilibrium which existed prior to application of the current. This
is facilitated by the absorption of energy at one junction and the
dissipation of energy from the other junction. The coupled pairs of
connectors can be connected in series to amplify the thermoelectric
effect. The direction of heat transfer is determined by the
polarity of the current; therefore, reversing the electrical
polarity of the current will reverse the thermal polarity of the
junctions.
[0016] Referring initially to FIG. 4, a section of an illustrative
embodiment of the thermoelectric wafer chuck of the present
invention is generally indicated by reference numeral 10. The
thermoelectric wafer chuck 10 includes a chuck base 12 which is
typically circular. Multiple fluid channels 14 extend through the
chuck base 12. Preferably, the fluid channels 14 extend directly
through the chuck base 12 without the use of coils, and the
thermoelectric wafer chuck 12 is therefore "coil-free". The fluid
channels 14 may extend through the chuck base 12 in a single loop
or multi-loop configuration to define one or multiple cooling
and/or heating zones 17a on the chuck 10. A supply (not shown) of a
heating or cooling fluid is provided in fluid communication with
the fluid channels 14 to distribute a heating or cooling gas or
liquid (not shown) through the coolant channels 14 in use of the
thermoelectric wafer chuck 10, as will be hereinafter
described.
[0017] An annular chuck wall 13 extends upwardly from the edge of
the chuck base 12. A wafer support plate 16 having a wafer support
surface 17 is supported by the chuck wall 13, in spaced-apart
relationship to the chuck base 12. A chuck interior 18, the purpose
of which will be hereinafter described, is defined between the
upper surface of the chuck base 12 and the lower surface of the
wafer support plate 16. At least one thermoelectric module 22 is
provided in the chuck interior 18. Preferably, a stacked
thermoelectric module 22a, which includes two or more single
thermoelectric modules 22, is provided in the chuck interior 18 as
will be hereinafter described.
[0018] Referring next to FIGS. 1-3, a portion of a single
thermoelectric module 22 is shown. Each thermoelectric module 22
typically includes a bottom isolation plate 24 and a top isolation
plate 28, each of which is typically ceramic. Multiple bottom
conductor plates 26 are provided on the upper surface of the bottom
isolation plate 24, and multiple top conductor plates 30 are
provided on the lower surface of the top isolation plate 28. The
bottom conductor plates 26 and top conductor plates 30 are an
electrically-conductive material, typically copper. As further
illustrated in FIG. 2, each of the bottom conductor plates 26
overlaps a pair of adjacent top conductor plates 30. On respective
sides of the thermoelectric module 22, the bottom conductor plates
26 are shown as terminal plates 26a and 26b, respectively, on the
upper surface of the bottom isolation plate 24.
[0019] Multiple n-type connectors 32 and p-type connectors 34 are
connected to each other in series through the bottom conductor
plates 26 and top conductor plates 30. Each n-type connector 32 of
each series spans a bottom conductor plate 26 and a top conductor
plate 30, and the adjacent p-type connector 34 of the series spans
the same top conductor plate 30 and the adjacent bottom conductor
plate 26. The next n-type connector 32 in the series contacts the
same bottom conductor plate 26 as is contacted by the previous
p-type connector 34 and a different top conductor plate 30.
Accordingly, proceeding from left to right in FIG. 2, each adjacent
pair of bottom conductor plates 26 is connected through an n-type
connector 32 and a p-type connector 34, respectively, whereas each
adjacent pair of top conductor plates 30 is connected through a
p-type connector 34 and an n-type connector 32, respectively. In
the foregoing manner, all of the n-type connectors 32 and the
p-type connectors 34 in the thermoelectric module 22 are
interconnected in series through the bottom conductor plates 26 and
the top conductor plates 30. A negative electrical lead 36 (which
may serve as either a negative or positive electrical lead
depending on the desired thermal polarity of the thermoelectric
module 22) is electrically connected to the terminal plate 26a, and
a positive electrical lead 38 (which may be positive or negative)
is electrically connected to the terminal plate 26b.
[0020] As shown in FIG. 3, in the thermoelectric chuck 10 (FIG. 4),
at least two single thermoelectric modules 22 are preferably
stacked and electrically connected to each other in series to form
a stacked thermoelectric module 22a. In FIG. 3, the negative lead
36 is connected to the lower thermoelectric module 22, whereas the
positive lead 38 is connected to the upper thermoelectric module
22, of the stacked thermoelectric module 22a. The upper and lower
thermoelectric modules 22 are electrically connected in series to
each other in the stacked thermoelectric module 22a through an
electrical connector 40.
[0021] Referring again to FIG. 4, the stacked thermoelectric module
22a is provided in the chuck interior 18 of the thermoelectric
wafer chuck 10. Alternatively, a single thermoelectric module 22
may be provided in the chuck interior 18. In the former case, the
bottom isolation plate 24 (FIG. 3) of the bottom thermoelectric
module 22 in the stacked thermoelectric module 22a rests on the
upper surface of the chuck base 12, whereas the top isolation plate
28 of the top thermoelectric module 22 in the stacked
thermoelectric module 22a thermally contacts the lower surface of
the wafer support plate 16. In the thermoelectric chuck 10,
multiple, independently-controlled single thermoelectric modules 22
or stacked thermoelectric modules 22a may be provided in the chuck
interior 18 in adjacent or concentric relationship to each other or
may be otherwise positioned with respect to each other to form
multiple, independently-controlled heating zones 17a on the wafer
support surface 17 during operation of the thermoelectric wafer
chuck 10. While the heating zones 17a shown in FIG. 4 are
concentric, it is understood that the heating zones 17a may be
arranged in any desired configuration on the wafer support surface
17.
[0022] Referring next to FIGS. 5 and 6, the thermoelectric wafer
chuck 10 is mounted in a processing chamber 44, which may be a
lithography scanner and track, an etching chamber, a CVD (chemical
vapor deposition) chamber, a PVD (physical vapor deposition)
chamber or other processing chamber in which heating and/or cooling
of a wafer are needed. The processing chamber 44 typically includes
a chamber wall 46 which defines a chamber interior 48 and includes
a gas inlet 50 in the top thereof for the introduction of
processing gases 54 into the chamber interior 48. As shown in FIG.
6, multiple gas outlets 52 are provided typically in the bottom of
the processing chamber 44. In the bottom view of FIG. 6, in which
the thermoelectric wafer chuck 10 is shown in section, the n-type
connectors 32 and p-type connectors 34 are shown as heat cells
which facilitate heating and/or cooling of a wafer (not shown)
resting on the wafer support surface 17 of the thermoelectric wafer
chuck 10 during fabrication of semiconductors on the wafer, as will
be hereinafter described.
[0023] In operation of the thermoelectric wafer chuck 10, a wafer
(not shown) is initially placed on the wafer support surface 17 of
the chuck 10 in the chamber interior 48 of the processing chamber
44. Depending on the type of processing to be carried out on the
wafer, processing gases 54 (FIG. 5) may be introduced into the
chamber interior 48 through the gas inlet 50. Simultaneously, the
wafer may be heated by operation of the thermoelectric wafer chuck
10. Accordingly, electrical current is distributed through the
stacked module 22a by facilitating flow of current through the
negative lead 36, the stacked module 22a and the positive lead 38,
respectively. In the stacked module 22a, the electrical current
flows in series through the bottom conductor plates 26, the n-type
connectors 32, the p-type connectors 34 and the top conductor
plates 30. As it flows through the n-type connectors 32 and the
p-type connectors 34, the electrical current, via the Peltier
effect, drives a transfer of heat from the bottom conductor plates
26 to the top conductor plates 30. This results in the production
of a cold side at the bottom isolation plate 24 and a heat sink (or
hot side) at the top isolation plate 28 of the stacked
thermoelectric module 22a. Consequently, the top isolation plate 28
heats the wafer support plate 16 and wafer support surface 17 of
the wafer chuck 10 to a desired set point temperature. At that
point, flow of current through the stacked module 22a may be
terminated or intermittently distributed through the stacked module
22a as needed to maintain the wafer support surface 17 as close as
possible to the set point temperature. Alternatively or
additionally, a heating fluid (not shown) may be distributed
through the fluid channels 14 of the chuck base 12 to heat the
wafer by conduction through the stacked thermoelectric module 22a
and wafer support plate 16.
[0024] When subsequent cooling of the wafer is necessary, flow of
electrical current through the stacked module 22a is terminated
and/or flow of the heating fluid through the fluid channels 14 is
stopped. Accordingly, electrical current is distributed in the
reverse direction through the positive lead 38, the stacked module
22a and the negative lead 36, respectively. In the n-type
connectors 32 and the p-type connectors 34, this drives a transfer
of heat from the top conductor plates 30 to the bottom conductor
plates 26, resulting in the production of a cold side at the top
isolation plate 28 and a heat sink (or hot side) at the bottom
isolation plate 24. Consequently, the top isolation plate 28
absorbs heat from the wafer through the wafer support plate 16 and
wafer support surface 17 until the wafer reaches the desired set
point temperature. At that point, flow of current through the
stacked module 22a may be terminated or intermittently distributed
through the stacked module 22a as needed to maintain the wafer
support surface 17 at the set point temperature. Alternatively or
additionally, a coolant fluid (not shown) may be distributed
through the coolant channels 14 of the chuck base 12 to absorb heat
from the wafer through the wafer support plate 16 and stacked
module 22a, respectively, until the desired set point temperature
of the wafer is achieved.
[0025] It will be appreciated by those skilled in the art that the
thermoelectric wafer chuck 10 of the present invention facilitates
rapid, dynamic and uniform wafer heating and cooling capability of
wafers, as well as zonal heating and/or cooling of wafers during
processing, as needed. Furthermore, the thermoelectric wafer chuck
10 is adaptable for heating and/or cooling wafers in any of a
variety of processing chambers or processes including but not
limited to lithography, etching, CVD (chemical vapor deposition),
PVD (physical vapor deposition) or any other processes in which
heating and/or cooling of wafers is needed during fabrication of
semiconductors.
[0026] While the preferred embodiments of the invention have been
described above, it will be recognized and understood that various
modifications can be made in the invention and the appended claims
are intended to cover all such modifications which may fall within
the spirit and scope of the invention.
* * * * *