U.S. patent application number 10/797315 was filed with the patent office on 2005-09-15 for multi-function slurry delivery system.
Invention is credited to Chang, Chao-Jung, Chen, Ping-Hsu, Chuang, Ping, Lin, Yu-Liang, Lo, Jui-Cheng, Tsai, Shang-Ting.
Application Number | 20050202763 10/797315 |
Document ID | / |
Family ID | 34920027 |
Filed Date | 2005-09-15 |
United States Patent
Application |
20050202763 |
Kind Code |
A1 |
Chen, Ping-Hsu ; et
al. |
September 15, 2005 |
Multi-function slurry delivery system
Abstract
A method and system for delivering a mixed slurry for use
chemical mechanical polishing operation. A first slurry may be
mixed with a second slurry to provide a mixed slurry thereof. A
flow rate and a mixing ratio associated with the mixed slurry can
be controlled to provide an accurate flow rate control and
adjustable mixing ratio thereof. The first slurry and the second
slurry may be mixed in-line utilizing an in-line mixing mechanism
to provide a mixed slurry thereof. Alternatively, the first and
second slurries may be pre-mixed utilizing a pre-mixing mechanism
to provide a mixed slurry there.
Inventors: |
Chen, Ping-Hsu; (Hsin-Chu,
TW) ; Chang, Chao-Jung; (Hsin-Chu, TW) ; Lo,
Jui-Cheng; (Hsin-Chu, TW) ; Lin, Yu-Liang;
(Hsin-Chu, TW) ; Tsai, Shang-Ting; (Hsin-Chu,
TW) ; Chuang, Ping; (Hsin-Chu, TW) |
Correspondence
Address: |
TUNG & ASSOCIATES
Suite 120
838 W. Long Lake Road
Bloomfield Hills
MI
48302
US
|
Family ID: |
34920027 |
Appl. No.: |
10/797315 |
Filed: |
March 9, 2004 |
Current U.S.
Class: |
451/60 |
Current CPC
Class: |
B24B 37/044 20130101;
B24B 57/02 20130101 |
Class at
Publication: |
451/060 |
International
Class: |
B24B 001/00 |
Claims
What is claimed is:
1. A method for delivering a mixed slurry for use in a chemical
mechanical polishing operation, said method comprising the steps
of: delivering a first slurry for use in a chemical mechanical
polishing operation; mixing said first slurry with a second slurry
to provide a mixed slurry thereof; and controlling a flow rate and
a mixing ratio associated with said mixed slurry, thereby providing
an accurate control of said flow rate and adjustable mixing ratios
thereof for use in enhancing chemical mechanical polishing
operations utilized in the fabrication of semiconductor
devices.
2. The method of claim 1 wherein the step of mixing said first
slurry with said second slurry to provide a mixed slurry, further
comprises the step of: mixing said first slurry with said second
slurry in-line to provide a mixed slurry thereof.
3. The method of claim 2 further comprising the step of adjusting
said mixing ratio by controlling said flow rate.
4. The method of claim 1 wherein the step of mixing said slurry
with said second slurry, further comprises the step of: pre-mixing
said first slurry with said second slurry to provide a mixed slurry
thereof.
5. The method of claim 4 further comprising the step of: adjusting
said mixing ratio by measuring a weight of said first slurry.
6. The method of claim 4 further comprising the step of: adjusting
said mixing ratio by adjusting a weight of said second slurry.
7. The method of claim 4 further comprising the steps of: adjusting
said mixing ratio by adjusting a weight of said first slurry and a
weight of said second slurry.
8. The method of claim 4 further comprising the steps of:
pre-mixing said first slurry and said second slurry in a pre-mixing
tank to provide said mixed slurry, wherein said pre-mixing tank is
associated with at least one load cell to control said mixing
ratio; controlling said flow rate of said mixed slurry delivered
from said pre-mixing tank to a chemical mechanical polishing device
utilizing a slurry pump associated with said-pre-mixing tank; and
thereafter delivering said mixed slurry to said chemical mechanical
polishing device.
9. The method of claim 1 wherein the step of mixing said slurry
with said second slurry, further comprises the step of: mixing said
first slurry with said second slurry in-line to provide a mixed
slurry thereof; and pre-mixing said first slurry with said second
slurry to provide a mixed slurry thereof.
10. The method of claim 1 further comprising the step of:
delivering said first slurry from a first supply tank linked to at
least one circulation pump, wherein said circulation pump is
operable in association with at least one slurry pump; and
delivering said second slurry from a second supply tank connected
to at least one circulation pump, wherein said second supply tank
is operable in association with at least one slurry pump; and
wherein said first and second supply tanks are operable in
association with at least one valve.
11. A system for delivering a slurry for use in a chemical
mechanical polishing operation, said system comprising: a first
slurry for use in a chemical mechanical polishing operation; a
mixing mechanism for mixing said first slurry with a second slurry
to provide a mixed slurry thereof; and a control mechanism for
controlling a flow rate and a mixing ratio associated with said
mixed slurry, thereby providing an accurate control of said flow
rate and adjustable mixing ratios thereof for use in enhancing
chemical mechanical polishing operations utilized in the
fabrication of semiconductor devices.
12. The system of claim 11 wherein said mixing mechanism further
comprises: in-line mixing mechanism for mixing said first slurry
with said second slurry in-line to provide a mixed slurry
thereof.
13. The system of claim 12 wherein said control mechanism permits
said mixing ratio to be adjusted by controlling said flow rate.
14. The system of claim 11 wherein said mixing mechanism further
comprises: a pre-mixing mechanism for pre-mixing said first slurry
with said second slurry to provide a mixed slurry thereof.
15. The system of claim 14 wherein said mixing ratio is adjustable
by measuring a weight of said first slurry.
16. The system of claim 14 wherein said mixing ratio is adjustable
by measuring a weight of said second slurry.
17. The system of claim 14 wherein said mixing ratio is adjustable
by adjusting a weight of said first slurry and a weight of said
second slurry.
18. The system of claim 14 wherein: said pre-mixing mechanism
further comprises a pre-mixing tank for pre-mixing said first
slurry and said second slurry to provide said mixed slurry, such
that said pre-mixing tank is associated with at least one load cell
to control said mixing ratio; and said flow rate of said mixed
slurry delivered from said pre-mixing tank to a chemical mechanical
polishing device is controllable utilizing a slurry pump associated
with said-pre-mixing tank.
19. The system of claim 11 wherein said mixing mechanism further
comprises: in-line mixing mechanism for mixing said first slurry
with said second slurry in-line to provide a mixed slurry thereof;
and pre-mixing mechanism for pre-mixing said first slurry with said
second slurry to provide a mixed slurry thereof.
20. The system of claim 11 wherein said delivery mechanism further
comprises: a first supply tank for delivering said first slurry,
wherein said first supply tank is linked to at least one
circulation pump, such that said circulation pump is operable in
association with at least one slurry pump; a second supply tank for
delivering said second slurry, wherein said second supply tank is
connected to at least one circulation pump, such that said second
supply tank is operable in association with at least one slurry
pump; and wherein said first and second supply tanks are operable
in association with at least one valve.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to semiconductor
fabrication methods and systems. The present invention also
generally relates to chemical mechanical polishing (CMP) devices
and techniques thereof. The present invention additionally relates
to slurry delivery methods and systems.
BACKGROUND OF THE INVENTION
[0002] Integrated circuits are typically formed on substrates,
particularly silicon wafers, by the sequential deposition of
conductive, semiconductive or insulative layers. After each layer
is deposited, the layer is etched to create circuitry features. As
a series of layers are sequentially deposited and etched, the outer
or uppermost surface of the substrate, i.e., the exposed surface of
the substrate, becomes successively more non-planar. This occurs
because the distance between the outer surface and the underlying
substrate is greatest in regions of the substrate where the least
etching has occurred, and least in regions where the greatest
etching has occurred. With a single patterned underlying layer,
this non-planar surface comprises a series of peaks and valleys
wherein the distance between the highest peak and the lowest valley
may be the order of 7000 to 10,000 Angstroms. With multiple
patterned underlying layers, the height difference between the
peaks and valleys becomes even more severe, and can reach several
microns.
[0003] This non-planar outer surface presents a problem for the
integrated circuit manufacturer. If the outer surface is
non-planar, then photo lithographic techniques used to pattern
photoresist layers might not be suitable, as a non-planar surface
can prevent proper focusing of the photolithography apparatus.
Therefore, there is a need to periodically planarize this substrate
surface to provide a planar layer surface. Planarization, in
effect, polishes away a non-planar, outer surface, whether
conductive, semiconductive, or insulative, to form a relatively
flat, smooth surface. Following planarization, additional layers
may be deposited on the outer surface to form interconnect lines
between features, or the outer surface may be etched to form vias
to lower features.
[0004] Chemical mechanical polishing is one accepted method of
planarization. This planarization method typically requires that
the substrate be mounted on a carrier or polishing head, with the
surface of the substrate to be polished exposed. The substrate is
then placed against a rotating polishing pad. In addition, the
carrier head may rotate to provide additional motion between the
substrate and polishing surface. Further, a polishing slurry,
including an abrasive and at least one chemically-reactive agent,
may be spread on the polishing pad to provide an abrasive chemical
solution at the interface between the pad and substrate.
[0005] Important factors in the chemical mechanical polishing
process are: the finish (roughness) and flatness (lack of large
scale topography) of the substrate surface, and the polishing rate.
Inadequate flatness and finish can produce substrate defects. The
polishing rate sets the time needed to polish a layer. Thus, it
sets the maximum throughput of the polishing apparatus.
[0006] Each polishing pad provides a surface, which, in combination
with the specific slurry mixture, can provide specific polishing
characteristics. Thus, for any material being polished, the pad and
slurry combination is theoretically capable of providing a
specified finish and flatness on the polished surface. The pad and
slurry combination can provide this finish and flatness in a
specified polishing time. Additional factors, such as the relative
speed between the substrate and pad, and the force pressing the
substrate against the pad, affect the polishing rate, finish and
flatness.
[0007] For the development of chemical mechanical polishing
technology in the 0.13 um range and beyond, a number of challenges
must be overcome, particularly in light of slurry delivery systems.
In order evaluate new types of slurries, it is necessary to control
the flow rate of such slurries and the mixing ratios of newly mixed
slurries. To date, an effective method and system for controlling
slurry flow rate and mixing ratios has not been achieved. In
addition, an effective slurry flow rate control and mixing ratio
method and system is necessary to mass production applications. The
present inventors have concluded, based on the foregoing, that a
need exists for a new method and system for controlling slurry flow
rate and mixing ratios thereof.
BRIEF SUMMARY OF THE INVENTION
[0008] The following summary of the invention is provided to
facilitate an understanding of some of the innovative features
unique to the present invention, and is not intended to be a full
description. A full appreciation of the various aspects of the
invention can be gained by taking the entire specification, claims,
drawings, and abstract as a whole.
[0009] It is therefore one aspect of the present invention to
provide an improved semiconductor fabrication method and
system.
[0010] It is therefore another aspect of the present invention
provide an improved method and system for delivering a slurry
utilized in a chemical mechanical polishing operation.
[0011] It is still another aspect of the present invention to
provide in-line mixing for and accurate control of flow rates of
slurries utilized in chemical mechanical polishing operations.
[0012] It is yet another aspect of the present invention to provide
pre-mixing functions, including accurately controlled rates
thereof, for slurries utilized in chemical mechanical polishing
operations.
[0013] The above and other aspects of the present invention can
thus be achieved as is now described. A method and system for
delivering a mixed slurry for use in a chemical mechanical
polishing operation is disclosed herein. According to the present
invention described herein, a first slurry may be delivered for use
in a chemical mechanical polishing operation. The first slurry may
be mixed with a second slurry to provide a mixed slurry thereof. A
flow rate and a mixing ratio associated with the mixed slurry can
be controlled to provide an accurate control of the flow rate and
adjustable mixing ratios for use in enhanced chemical mechanical
polishing operations utilized in the fabrication of semiconductor
devices.
[0014] The first slurry and the second slurry may be mixed in-line
utilizing an in-line mixing mechanism to provide a mixed slurry
thereof. In an in-line mixing scenario, the mixing ratio may be
adjusted by controlling the flow rate of the mixed slurry and/or
the first slurry and/or second slurry. Alternatively, the first and
second slurries may be pre-mixed utilizing a pre-mixing mechanism
to provide a mixed slurry there. In a pre-mixing scenario, the
mixing ratio may be adjusted by measuring the weight of the first
slurry and/or the second slurry. The pre-mixing mechanism may
comprise a pre-mixing tank, such that the pre-mixing tank is
associated with at least one load cell to control the mixing
ratio.
[0015] The flow rate of the mixed slurry delivered from the
pre-mixing tank to a chemical mechanical polishing device can be
controlled utilizing a slurry pump associated with the pre-mixing
tank. The mixed slurry can thereafter be delivered to the chemical
mechanical polishing device and/or systems thereof. The pre-mixing
mechanism and the in-line mixing mechanism may be integrated into a
multi-function slurry delivery system and/or device. The first
slurry can be delivered from a first supply tank linked to at least
one circulation pump, wherein the circulation pump is operable in
association with at least one slurry pump. The second slurry can be
delivered from a second supply tank connected to at least one
circulation pump, wherein the second supply tank is operable in
association with at least one slurry pump. The first and second
supply tanks are operable in association with at least one
valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The accompanying figures, in which like reference numerals
refer to identical or functionally-similar elements throughout the
separate views and which are incorporated in and form part of the
specification, further illustrate the present invention and,
together with the detailed description of the invention, serve to
explain the principles of the present invention.
[0017] FIG. 1 depicts a block diagram illustrating a multi-function
slurry delivery system, in accordance with a preferred embodiment
of the present invention; and
[0018] FIG. 2 illustrates a high-level block diagram illustration a
multi-function slurry delivery system, in accordance with a
preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The particular values and configurations discussed in these
non-limiting examples can be varied and are cited merely to
illustrate embodiments of the present invention and are not
intended to limit the scope of the invention.
[0020] FIG. 1 depicts a block diagram illustrating a multi-function
slurry delivery system 10, in accordance with a preferred
embodiment of the present invention. System 10 generally includes a
first supply tank 12 and a second supply tank 14. Supply tank 12
can contain a slurry A, while supply tank B can contain a slurry B.
Supply tank 12 is connected to a circulation pump 16. Supply tank
14 is generally connected to a circulation pump 18. Circulation
pump 16 is connected to supply tank 12 by lines 17 and 13 through
which a slurry may flow.
[0021] A slurry may thus enter supply tank 12 though line 12 and
exit through line 17. A valve 32 is situated between circulation
pump 16 and a delivery pump 20 on line 33. Line 33 is connected to
line 13. A line 37 connects delivery pump 20 to an in-line mixing
mechanism 30, which can be utilized to control the flow rate and
mixing ratio of a slurry being mixed via in-line mixing mechanism
30. In-line mixing mechanism 30 in turn can deliver a slurry (e.g.,
a mixed slurry) to a chemical mechanical polishing device 38 or
system thereof through line 29. In-line mixing mechanism is
additionally connected to a delivery pump 22 by a line 23 through
which a slurry may flow.
[0022] Delivery pump 22 is connected to a line 41 which is
connected to a valve 36, which in turn is connected to a line 15
that is connected to a line 19. Line 19 connects circulation pump
18 to supply tank 14 (i.e., second supply tank). Slurry can be
delivered to supply tank 14 through line 19 and can exit supply
tank 14 through a line 21, which in turn is connected to
circulation pump 18. A line 46 is connected to line 19. Line 46 is
connected to a valve 38, which in turn is connected to a line 48.
Line 48 is connected to a pre-mixing mechanism 24, which can be
configured as a pre-mixing tank.
[0023] Pre-mixing mechanism 24 is associated with one or more load
cells 40, 42, and 44. Pre-mixing mechanism 24 is additionally
connected to a line 49 which can deliver slurry (i.e., pre-mixed
slurry) to a delivery pump 26 which in turn can deliver the slurry
via a line 47 to chemical polishing device 28. Delivery pump 26 can
be utilized to control the flow rate of a slurry being mixed in
pre-mixing mechanism 24. The mixing ratio of the slurry delivered
via pre-mixing tank 24 can be adjusted by measuring the slurry's
weight.
[0024] One or more load cells 40, 42 and 44 can be utilized to
control the mixing ratio of the slurry being mixed in pre-mixing
mechanism 24. Slurry can enter pre-mixing mechanism 24 through line
48 or a line 43. Line 43 is connected to a valve 34 which in turn
is connected to a line 35 that is connected to line 13. A slurry
can thus be delivered directly to chemical mechanical polishing
device 28 from first supply tank 12 or second supply tank 14.
[0025] FIG. 2 illustrates a high-level block diagram illustration a
multi-function slurry delivery system 50, in accordance with a
preferred embodiment of the present invention. Note that system 50
of FIG. 2 is analogous to system 10 of FIG. 1. System 50 generally
includes an in-line mixing mechanism 52 and a pre-mixing mechanism
54. In-line mixing mechanism 52, as indicated at block 56, permits
a slurry mixing ratio to be adjusted by controlling the flow rate
of the slurry. Pre-mixing system 54, as indicated at block 58,
permits a mixing ratio of the slurry to be adjusted by measuring
the weight of the slurry. In-line mixing mechanism 52 of FIG. 2 is
generally analogous to in-line mixing mechanism 30 of FIG. 1.
Pre-mixing mechanism 54 of FIG. 2 is generally analogous to
pre-mixing mechanism 24 of FIG. 1.
[0026] Pre-mixing mechanism 52 can thus be implemented separately
or together with pre-mixing tank 54 to form system 50. System 50
provides an innovative process capability with in-line and
pre-mixing functions in one recipe. System 50 can supply slurry to
a varying CMP tools and is compatible with a variety of CMP
processes (e.g., W, STI, ILD, Cu, etc). System 52 can be easily
applied to mass production scenarios and operations, and can solve
the slurry contamination problem caused by the use of central
supply systems. System 52 can also provide a local supply system
for every CMP machine or device currently in use in industry.
[0027] Based on the foregoing, it can thus be appreciated that FIG.
1 and FIG. 2 generally describe a method and system for delivering
a mixed slurry for use in a chemical mechanical polishing operation
is disclosed herein. According to the present invention described
herein, a first slurry may be delivered for use in a chemical
mechanical polishing operation. The first slurry may be mixed with
a second slurry to provide a mixed slurry thereof. A flow rate and
a mixing ratio associated with the mixed slurry can be controlled
to provide an accurate control of the flow rate and adjustable
mixing ratios for use in enhanced chemical mechanical polishing
operations utilized in the fabrication of semiconductor
devices.
[0028] The first slurry and the second slurry may be mixed in-line
utilizing an in-line mixing mechanism (e.g., in-line mixing
mechanism 42) to provide a mixed slurry thereof. In an in-line
mixing scenario, the mixing ratio may be adjusted by controlling
the flow rate of the mixed slurry and/or the first slurry and/or
second slurry. Alternatively, the first and second slurries may be
pre-mixed utilizing a pre-mixing mechanism (e.g., pre-mixing
mechanism 24) to provide a mixed slurry there. In a pre-mixing
scenario, the mixing ratio may be adjusted by measuring the weight
of the first slurry and/or the second slurry. The pre-mixing
mechanism may comprise a pre-mixing tank, such that the pre-mixing
tank is associated with at least one load cell to control the
mixing ratio. The pre-mixing tank may also be connected to at least
one delivery pump via a slurry line (e.g., line 49). Such a
delivery pump (e.g., delivery pump 26) can permit a slurry to be
pumped to a chemical mechanical polishing devices.
[0029] The flow rate of the mixed slurry delivered from the
pre-mixing tank to a chemical mechanical polishing device can be
controlled utilizing a slurry pump associated with the-pre-mixing
tank. The mixed slurry can thereafter be delivered to the chemical
mechanical polishing device and/or systems thereof. The pre-mixing
mechanism and the in-line mixing mechanism may be integrated into a
multi-function slurry delivery system and/or device. The first
slurry can be delivered from a first supply tank (e.g., supply tank
12) linked to at least one circulation pump, wherein the
circulation pump is operable in association with at least one
slurry pump. The second slurry can be delivered from a second
supply tank (e.g., supply tank 14) connected to at least one
circulation pump, wherein the second supply tank is operable in
association with at least one slurry pump. The first and second
supply tanks are operable in association with at least one
valve.
[0030] The embodiments and examples set forth herein are presented
to best explain the present invention and its practical application
and to thereby enable those skilled in the art to make and utilize
the invention. Those skilled in the art, however, will recognize
that the foregoing description and examples have been presented for
the purpose of illustration and example only. Other variations and
modifications of the present invention will be apparent to those of
skill in the art, and it is the intent of the appended claims that
such variations and modifications be covered. The description as
set forth is thus not intended to be exhaustive or to limit the
scope of the invention. Many modifications and variations are
possible in light of the above teaching without departing from
scope of the following claims. It is contemplated that the use of
the present invention can involve components having different
characteristics. It is intended that the scope of the present
invention be defined by the claims appended hereto, giving full
cognizance to equivalents in all respects.
* * * * *