U.S. patent application number 09/908132 was filed with the patent office on 2002-03-07 for method and apparatus for removing processing liquid from a processing liquid delivery line.
Invention is credited to Jackson, Michael, Mandrekar, Tushar, Tolia, Anish.
Application Number | 20020026951 09/908132 |
Document ID | / |
Family ID | 22957224 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020026951 |
Kind Code |
A1 |
Tolia, Anish ; et
al. |
March 7, 2002 |
Method and apparatus for removing processing liquid from a
processing liquid delivery line
Abstract
A method and apparatus for desorbing processing liquid from a
processing liquid delivery line is provided. Non-thermal energy,
such as ultrasonic energy or electromagnetic energy, is applied to
a processing liquid delivery line. The non-thermal energy may be
applied directly to the processing liquid delivery line, or may be
applied indirectly via a conducting medium which distributes the
energy along the length of the processing liquid delivery line.
When non-thermal energy in the form of electromagnetic energy is
employed, the frequency of the electromagnetic energy is adjusted
to match the vibrational frequency of the absorbed molecules of
processing liquid.
Inventors: |
Tolia, Anish; (San Jose,
CA) ; Mandrekar, Tushar; (Santa Clara, CA) ;
Jackson, Michael; (Sunnyvale, CA) |
Correspondence
Address: |
PATENT COUNSEL
APPLIED MATERIALS, INC.
Legal Affairs Department
P.O. BOX 450A
Santa Clara
CA
95052
US
|
Family ID: |
22957224 |
Appl. No.: |
09/908132 |
Filed: |
July 18, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09908132 |
Jul 18, 2001 |
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09252717 |
Feb 19, 1999 |
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6305392 |
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Current U.S.
Class: |
134/1 ; 134/169R;
134/22.12; 137/242 |
Current CPC
Class: |
B01J 2219/0877 20130101;
C23C 16/4408 20130101; B08B 2209/005 20130101; B65G 53/521
20130101; Y10T 137/4273 20150401; Y10T 137/4259 20150401; B01J
4/008 20130101; Y10T 137/4245 20150401; B01J 19/10 20130101; B01J
19/12 20130101; B08B 9/032 20130101; C23C 16/4407 20130101 |
Class at
Publication: |
134/1 ; 137/242;
134/22.12; 134/169.00R |
International
Class: |
B08B 009/027 |
Claims
The invention claimed is:
1. A method of removing processing liquid from a processing liquid
delivery line comprising: pumping a bulk amount of processing
liquid from the processing liquid delivery line; and applying
non-thermal energy to the processing liquid delivery line and
thereby desorbing processing liquid from the processing liquid
delivery line.
2. The method of claim 1 wherein applying non-thermal energy to the
processing liquid delivery line comprises supplying ultrasonic
energy to the processing liquid delivery line.
3. The method of claim 1 wherein applying non-thermal energy to the
processing liquid delivery line comprises distributing non-thermal
energy along the processing liquid delivery line by applying
non-thermal energy to a conducting medium which surrounds the
processing liquid delivery line.
4. The method of claim 3 wherein applying non-thermal energy to the
processing liquid delivery line comprises supplying ultrasonic
energy to the conducting medium.
5. The method of claim 3 wherein distributing non-thermal energy
along the processing liquid delivery line comprises: providing a
sheath which surrounds the exterior surface of the processing
liquid delivery line; and providing a conducting medium which fills
the region between the sheath and the exterior surface of the
processing liquid delivery line so as to couple non-thermal energy
to the exterior surface of the processing liquid delivery line.
6. The method of claim 1 wherein applying non-thermal energy to the
processing liquid delivery line comprises supplying electromagnetic
energy to the processing liquid delivery line.
7. The method of claim 6 further comprising adjusting the frequency
of the electromagnetic energy to match the vibrational frequency of
the absorbed processing liquid.
8. The method of claim 7 wherein supplying electromagnetic energy
to the processing liquid delivery line comprises distributing
non-thermal energy along the processing liquid delivery line by
applying non-thermal energy to a conducting medium which surrounds
the processing liquid delivery line.
9. A method comprising: providing a processing liquid delivery line
adapted to deliver processing liquid to a processing chamber while
a semiconductor process is performed within the processing chamber;
pumping a bulk amount of processing liquid from the processing
liquid delivery line; and applying non-thermal energy to the
processing liquid delivery line and thereby desorbing processing
liquid from the processing liquid delivery line.
10. A method comprising: providing a system having: a processing
liquid delivery line configured to deliver processing liquid to a
processing chamber while a semiconductor process is performed
within the processing chamber; a pump coupled to the processing
liquid delivery line; and a source of non-thermal energy
operatively coupled to the processing liquid delivery line and
configured to transmit non-thermal energy from the source to the
processing liquid delivery line, the non-thermal energy being
configured so as to affect desorption of processing liquid from the
processing liquid delivery line; pumping a bulk amount of
processing liquid from the processing liquid delivery line; and
applying non-thermal energy to the processing liquid delivery line
and thereby desorbing processing liquid from the processing liquid
delivery line.
11. The method of claim 10 wherein applying non-thermal energy
comprises applying ultrasonic energy.
12. The method of claim 10 wherein applying non-thermal energy
comprises applying electromagnetic energy.
13. The method of claim 12 wherein applying electromagnetic energy
comprises adjusting the frequency of the electromagnetic energy
applied to the processing liquid delivery line to the vibrational
frequency of processing liquid absorbed by the processing liquid
delivery line.
14. The method of claim 10 further comprising coupling a conducting
medium between the processing liquid delivery line and the source
of non-thermal energy.
15. The method of claim 14 wherein the conducting medium extends
around the exterior surface of the processing liquid delivery
line.
16. The method of claim 1 further comprising: providing a sheath
which surrounds the exterior surface of the processing liquid
delivery line; and providing a conducting medium which fills the
region between the sheath and the exterior surface of the
processing liquid delivery line so as to couple non-thermal energy
to the exterior surface of the processing liquid delivery line.
17. A method comprising: providing a processing system having: a
processing chamber; a processing liquid delivery line configured to
deliver processing liquid to the processing chamber while a
semiconductor process is performed within the processing chamber; a
pump coupled to the processing liquid delivery line; and a source
of non-thermal energy operatively coupled to the processing liquid
delivery line and configured to transmit non-thermal energy from
the source to the processing liquid delivery line, the non-thermal
energy being configured so as to affect desorption of processing
liquid from the processing liquid delivery line; pumping a bulk
amount of processing liquid from the processing liquid delivery
line; and applying non-thermal energy to the processing liquid
delivery line and thereby desorbing processing liquid from the
processing liquid delivery line.
18. A method comprising: providing a processing system having: a
processing chamber; a processing liquid delivery line configured to
deliver processing liquid to the processing chamber while a
semiconductor process is performed within the processing chamber; a
pump coupled to the processing liquid delivery line; a sheath which
surrounds an exterior surface of the processing liquid delivery
line; a conducting medium which fills a region between the sheath
and the exterior surface of the processing liquid delivery line;
and a source of non-thermal energy coupled to the sheath so as to
couple non-thermal energy to the exterior surface of the processing
liquid delivery line, the non-thermal energy being configured so as
to affect desorption of processing liquid from the processing
liquid delivery line; pumping a bulk amount of processing liquid
from the processing liquid delivery line; and applying non-thermal
energy to the processing liquid delivery line and thereby desorbing
processing liquid from the processing liquid delivery line.
19. A method comprising: providing a system having: a processing
liquid delivery line configured to deliver processing liquid to a
processing chamber while a semiconductor process is performed
within the processing chamber; a source of non-thermal energy
operatively coupled to the processing liquid delivery line and
configured to transmit non-thermal energy from the source to the
processing liquid delivery line, the non-thermal energy being
configured so as to affect desorption of processing liquid from the
processing liquid delivery line; and a frequency adjuster coupled
to the source of non-thermal energy and configured to adjust the
frequency of the non-thermal energy transmitted from the source of
non-thermal energy to a vibrational frequency of processing liquid
absorbed by the processing liquid delivery line; pumping a bulk
amount of processing liquid from the processing liquid delivery
line; and applying non-thermal energy to the processing liquid
delivery line and thereby desorbing processing liquid from the
processing liquid delivery line.
Description
[0001] This application is a division of U.S. patent application
Ser. No. 09/252,717, filed Feb. 19, 1999, which is hereby
incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to processing liquid delivery
systems for processing chambers, and more specifically to the
removal of processing liquid from a processing liquid delivery line
of a processing liquid delivery system.
BACKGROUND OF THE INVENTION
[0003] Many semiconductor processes such as chemical vapor
deposition (CVD) employ vaporized processing liquids. These
vaporized processing liquids are generated and supplied to a
processing chamber via a processing liquid delivery system
comprising an interconnection of pipes, valves, flow regulators and
vaporizing mechanisms. Typically a separate vaporizing mechanism is
provided for vaporizing each processing liquid, and is coupled to a
source of processing liquid and a source of carrier gas. Although a
number of vaporizing mechanisms exist (e.g., bubblers, injection
valves, etc.), most conventional processing liquid delivery systems
employ a plurality of injection valves for vaporizing processing
liquids to be delivered to a processing chamber.
[0004] A typical injection valve comprises a processing liquid
inlet for receiving a pressurized processing liquid, a carrier gas
inlet for receiving a pressurized inert carrier gas, and an outlet
for delivering a vaporized processing liquid/carrier gas mixture.
The injection valve is heated such that when the processing liquid
is injected into the carrier gas, the heat and the pressure
difference between the two sides of the injection valve cause the
processing liquid to vaporize.
[0005] Over time injection valves may clog or fail (e.g., due to
deposit formation within the injection valve from the interaction
of processing liquid with other processing chemicals or with the
injection valve itself) and must be replaced. However, the process
of injection valve replacement is complicated when the processing
liquid vaporized by the injection valve reacts deleteriously with
air (e.g., with moisture, oxygen, etc.) to form by-products (e.g.,
solid films such as oxides) that can damage the processing liquid
delivery system or the processing chamber, contaminate subsequently
processed semiconductor wafers or harm humans or the environment
(e.g., are toxic).
[0006] To prevent deleterious processing liquid formation during
injection valve replacement, if possible, processing liquid is
purged from all processing liquid delivery lines that will be
exposed to atmosphere when the clogged injection valve is removed.
However, as described with reference to FIG. 1, within conventional
processing liquid delivery systems the purging process is
difficult, particularly when processing liquids with strong
adhesive properties such as metal-organics (e.g.,
tetrakis(dimethylamino)titanium (TDMAT)) must be purged from
processing liquid delivery lines.
[0007] FIG. 1 is schematic view of a conventional processing liquid
delivery system 11 ("conventional system 11") for delivering
vaporized processing liquid to a processing chamber 12. The
conventional system 11 comprises a source of processing liquid 13
operatively coupled (i.e., coupled either directly or indirectly so
as to operate) to an injection valve 15 via a processing liquid
delivery line 17. Note that the processing liquid delivery line 17
is shown broken to indicate that the source of processing liquid 13
may be a substantial distance (e.g., about 10-15 feet) from the
injection valve 15.
[0008] Disposed along and forming a part of the processing liquid
delivery line 17 are a first isolation valve 19, a second isolation
valve 21, a liquid flow meter 23 and a third isolation valve 25.
The first isolation valve 19 is positioned near the source of
processing liquid 13, the third isolation valve 25 is positioned
near the injection valve 15, the liquid flow meter 23 is positioned
near the third isolation valve 25, and the second isolation valve
21 is positioned near the liquid flow meter 23, as shown. A large
number of other isolation valves typically are present along the
processing liquid delivery line 17 but are omitted for clarity.
[0009] The conventional system 11 also comprises a source of
purging gas 27 (e.g., nitrogen, argon, or some other gas which does
not react with the processing liquid) operatively coupled to the
processing liquid delivery line 17 via a purging gas line 29, and a
pump 31 (e.g., a mechanical pump) operatively coupled to the
processing liquid delivery line 17 via a pump line 33. Disposed
along and forming a part of the purging gas line 29 is a purge
valve 35, and disposed along and forming a part of the pump line 33
is a pump valve 37.
[0010] During normal operation of the conventional system 11, the
first isolation valve 19, the second isolation valve 21 and the
third isolation valve 25 are open to allow processing liquid to
flow from the source of processing liquid 13 to the injection valve
15 at a rate controlled by the liquid flow meter 23. The purge
valve 35 and the pump valve 37 are closed to prevent processing
liquid from being purged by the source of purging gas 27 and from
being pumped by the pump 31.
[0011] If the injection valve 15 subsequently becomes clogged and
must be replaced, the injection valve 15 is isolated from the
source of processing liquid 13 by closing the first isolation valve
19. Assuming the processing liquid is a metal-organic substance
such as TDMAT, the injection valve 15 cannot be directly
disconnected from the conventional system 11 without posing a
substantial health risk to the technician removing the injection
valve 15 and without posing a substantial damage risk to the
conventional system 11. TDMAT, for instance, reacts with moisture
in the air to form by-products that are harmful to humans (e.g.,
amines) and solid films (e.g., oxides) that will contaminate the
entire conventional system 11. Processing liquid, therefore, must
be purged from the processing liquid delivery line 17 prior to
removing the injection valve 15.
[0012] To purge processing liquid from the processing liquid
delivery line 17, while the first isolation valve 19 is closed and
the second isolation valve 21 and the third isolation valve 25 are
open, the purge valve 35 and the pump valve 37 are opened. Purging
gas thereby flows from the source of purging gas 27, through the
purging gas line 29, through the processing liquid delivery line 17
and through the pump line 33 to the pump 31. The purging gas
dislodges processing liquid particles from the surfaces of the
processing liquid delivery line 17, and the dislodged particles are
pumped from the processing liquid delivery line 17 via the pump 31.
Pump/purge cycles (wherein the purge valve 35 is closed for a time
period while the pump 31 continues to pump processing liquid and
purging gas from the processing liquid delivery line 17, followed
by a time period wherein the purge valve 35 is opened so as to
introduce more purging gas to the processing liquid delivery line
17) may be performed to aid in processing liquid removal from the
processing liquid delivery line 17.
[0013] For processing liquids having strong adhesive properties
(e.g., metal-organics), the pump/purge process described above does
not effectively removing processing liquid from the processing
liquid delivery line 17 to a level sufficient to prevent
deleterious by-product formation when the injection valve 15 is
disconnected from the conventional system 11. This is particularly
true for TDMAT.
[0014] One approach to improving the purging effectiveness of the
conventional system 11 is to employ thermal methods which heat the
relevant processing liquid path to desorb processing liquid
therefrom. Thermal methods, however, can damage rubber parts (e.g.,
valve seats), and can lead to decomposition of the processing
liquid, generating particles and the problems associated therewith.
Rubber parts, with added expense, can be designed to withstand
thermal desorption temperatures. Decomposition, on the other hand,
is unavoidable because processing liquid desorption and processing
liquid decomposition may occur in the same temperature range. Many
semiconductor processing liquids such as (TDMAT, dimethyl aluminum
hydride (DMAH), (Trimethylvinylsilyl)hexafluoro- acetylacetonato
Copper 1 (CupraSelect.RTM.), etc.) deposit metal constituents as
they decompose. The deposited metal may clog the processing liquid
delivery line or clog downstream valves, and thus may further
increase downtime costs. Even if clogging does not result, metals
deposited in the processing liquid delivery line can flake
therefrom, contaminating the processing chamber and potentially
destroying any wafers being processed therein.
[0015] Accordingly, a need exists for a processing liquid purging
method and apparatus that more effectively purges a processing
liquid from a processing liquid delivery system without causing
processing liquid decomposition and its attendant problems.
SUMMARY OF THE INVENTION
[0016] The present invention operatively couples a source of
non-thermal energy (e.g., ultrasonic energy, electromagnetic
energy, etc.) to a processing liquid delivery line from which
processing liquid must be desorbed. The non-thermal energy source
provides the energy required to desorb liquid molecules from the
processing liquid delivery line. This non-thermal energy is
transmitted from the source to the processing liquid delivery line
where the non-thermal energy affects processing liquid desorption
without decomposing the processing liquid, and without harming
rubber components.
[0017] The non-thermal energy may be coupled directly to the
processing liquid delivery line, or may be coupled to a conducting
medium which surrounds the processing liquid delivery line and
distributes the non-thermal energy along the processing liquid
delivery line to facilitate uniform/non-localized desorption. In a
preferred embodiment, when ultrasonic energy is employed, a sheath
surrounds the processing liquid delivery line, and the conducting
medium (e.g., a liquid or a gel) fills a space between the
processing liquid delivery line and the sheath.
[0018] When electromagnetic energy is employed as the non-thermal
energy, the electromagnetic energy source preferably is supplied
with a frequency adjuster, and the frequency of the electromagnetic
energy is adjusted to match the vibrational frequency of the
absorbed processing liquid molecules.
[0019] The present invention thus provides an effective and
inexpensive method and apparatus for desorbing processing liquid
from a processing liquid delivery line. Because non-thermal energy
is employed, heating of processing liquids is minimized so that
processing liquids do not decompose, and rubber components need not
be specially designed for high temperature exposures. Further, it
is believed that the present invention will reduce processing
liquid desorption times as compared to prior art methods.
[0020] Other objects, features and advantages of the present
invention will become more fully apparent from the following
detailed description of the preferred embodiments, the appended
claims and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a diagrammatic side elevational view of a
conventional processing liquid delivery system, as previously
described;
[0022] FIG. 2 is a front cross sectional view of an inventive
processing liquid delivery line; and
[0023] FIG. 3 is a diagrammatic side elevational view of a
processing liquid delivery system similar to that of FIG. 1, but
employing the inventive processing liquid delivery line of FIG.
2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] FIG. 2 is a front cross sectional view of an inventive
processing liquid delivery system 41. The processing liquid
delivery system 41 comprises a processing liquid delivery line 43
and a source of non-thermal energy 45 operatively coupled to the
processing liquid delivery line 43. The source of non-thermal
energy 45 may generate any type of non-thermal energy which affects
desorption of processing liquid from the walls of the processing
liquid delivery line 43, such as ultrasonic energy or
electromagnetic energy.
[0025] A frequency adjuster 47 optionally may be coupled to the
source of non-thermal energy 45 to adjust the frequency thereof
(e.g., when the source of non-thermal energy is an electromagnetic
energy source). Specifically, the optional frequency adjuster 47
enables the electromagnetic frequency output by the source of
non-thermal energy 45 to be adjusted to match the frequency at
which the absorbed molecules of processing liquid vibrate. Due to
resonance effects, electromagnetic energy thereby is very
efficiently transferred to the processing liquid.
[0026] The source of non-thermal energy 45 is operatively coupled
to the processing liquid delivery line 43 (e.g., one or more leads
49) either directly, or indirectly via a conducting medium 51.
Preferably, if the non-thermal energy source 45 is an ultrasonic
energy source, the processing liquid delivery line 43 further
comprises a sheath 53 which surrounds the outer surface of the
processing liquid delivery line 43, in a spaced relationship
therewith. The conducting medium 51 fills the space between the
processing liquid delivery line 43 and the sheath 53, and comprises
a material (e.g., a gel or liquid) which readily transmits the
non-thermal energy so as to distribute the non-thermal energy along
the length of the conducting medium 51. Thus non-thermal energy
also is distributed along the length of the processing liquid
delivery line 43, preventing localized desorption.
[0027] When the source of non-thermal energy 45 is an ultrasound
generator, the conducting medium 51 is a sound conducting medium.
When the source of non-thermal energy 45 is an electromagnetic
energy source (e.g., an RF source, a microwave source, etc.), the
electromagnetic energy source may be coupled directly to the
processing liquid delivery line 43 if desired, with the processing
liquid delivery line 43 itself serving as the conducting medium
(e.g., because the line 43 typically is a metal). The operation of
the inventive processing liquid delivery line 43 is described below
with reference to FIG. 3.
[0028] FIG. 3 is a diagrammatic side elevational view of a
processing liquid delivery system 49 similar to that of FIG. 1, but
employing the processing liquid delivery line 43 of FIG. 2. Only
those aspects which differ from the conventional processing liquid
delivery system 11 of FIG. 1 are described. Specifically, as shown
in FIG. 3, that portion of the processing line which is exposed
(i.e., not sealed from the external environment) during replacement
of a malfunctioning liquid flow meter 23, or during replacement of
a malfunctioning injection valve 15 comprises the inventive
processing liquid delivery line 43 of FIG. 2.
[0029] In operation, in order to repair or replace the liquid flow
meter 23 or the injection valve 15, the first isolation valve 19 is
closed and, while the second isolation valve 21 and the third
isolation valve 25 remain open, the purge valve 35 and the pump
valve 37 are opened. Purging gas thereby flows from the source of
purging gas 27, through the purging gas line 29, through the
processing liquid delivery line 17 and through the pump line 33 to
the pump 31. The purging gas dislodges processing liquid particles
from the surfaces of the processing liquid delivery line 17, and
the dislodged particles and that portion of the processing liquid
which is not absorbed by the walls of the processing liquid
delivery line 43, are pumped from both the conventional portion 17
of the processing liquid delivery line, and the inventive portion
43 of the processing liquid delivery line. Thereafter, the source
of non-thermal energy 45 is engaged and non-thermal energy (e.g.,
ultrasound waves, electromagnetic waves, etc.) is transmitted from
the source of non-thermal energy 45 to the processing liquid
delivery line 43.
[0030] If ultrasonic energy is employed, the non-thermal energy
preferably is transmitted from the source 45 to the sheath 53 via
the lead 49. The conducting medium 51 distributes the non-thermal
energy along the entire outer surface of the processing liquid
delivery line 43. The non-thermal energy vibrates the walls of the
processing liquid delivery line 43, and processing liquid absorbed
by the walls of the processing liquid delivery line 43 is energized
by the non-thermal energy and is desorbed from the processing
liquid delivery line 43. If electromagnetic energy is employed, the
non-thermal energy preferably is directly transmitted from the
source 45 to the processing liquid delivery line 43. The processing
liquid delivery line 43 itself may serve as the conducting medium
51 and distribute the non-thermal, electromagnetic energy along the
entire outer surface of the processing liquid delivery line 43. The
frequency of the electromagnetic energy is tuned to the vibrational
frequency of the processing liquid, and processing liquid absorbed
by the walls of the processing liquid delivery line 43 is energized
by the electromagnetic energy and is desorbed from the processing
liquid delivery line 43.
[0031] Preferably, while the source of non-thermal energy 45 is
engaged, the pumping and purging process described with reference
to FIG. 1 is performed to remove processing liquid which desorbs
from the walls of the processing liquid delivery line 17. The
number and length of pump/purge cycles depends on the distance to
the pump and the length of the processing liquid delivery line 43
from which processing liquid must be desorbed.
[0032] The foregoing description discloses only the preferred
embodiments of the invention, modifications of the above disclosed
apparatus and method which fall within the scope of the invention
will be readily apparent to those of ordinary skill in the art. For
instance, the configuration of the processing liquid delivery
system of FIG. 3 is merely exemplary. The inventive processing
liquid delivery line may be used in any processing liquid delivery
system. Similarly, the purging process described with reference to
FIG. 3 is merely exemplary. The non-thermal energy may be employed
during or between pumping and purging cycles. Further, other
sources of non-thermal energy may be employed (e.g.,
megasonic).
[0033] Accordingly, while the present invention has been disclosed
in connection with the preferred embodiments thereof, it should be
understood that other embodiments may fall within the spirit and
scope of the invention, as defined by the following claims.
* * * * *